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Physical! 
Sci .Lib. 

TN 
24 
C3 
A3 
NO. 201 


PHYSICAL  S«K 

AN  EXPLANATORY  TEXT      SI 
TO  ACCOMPANY 
THE    1:750,000   SCALE 
FAULT  AND   GEOLOGIC   MAPS 
OF  CALIFORNIA 


PURPOSE  AND  USE 

EVOLUTION  OF  FAULT  AND  GEOLOGIC  MAPS 

FAULTS  AND  EARTHQUAKES 

MAJOR  STRUCTURAL  BLOCKS  OF  CALIFORNIA 

FAULT  PATTERNS 

VOLCANOES 

THERMAL  SPRINGS  AND  WELLS 

INDEXES  TO:     Faults 

Hot  Springs 

Formations 

Source  Data 


1  s^l 

STATE  OF  CALIFORNIA     ' 

GEORGE  DEUKMEJiAN 
GOVERNOR 

H^^m 

\  \ '  ¥  ^'WS<^)  ■ 

Pi^lNES  AND  GEOLOGY  y^J 

THE  RESOURCES  AGENCY 

GORDON  K   VAN  VLECK 
SECRETARY  FOR  RESOURCES 

BULLETIN  201 

DEPARTMENT  OF  CONSERVATION 

RANDALL  M   WARD 
DIRECTOR 

-J 


BULLETIN  201 


AN  EXPLANATORY  TEXT 

TO  ACCOMPANY 

THE  1:750,000  SCALE 

FAULT  AND  GEOLOGIC  MAPS 

OF  CALIFORNIA 


By 
Charles  W.  Jennings 

Geologist 


1985 


L^   CALIFORNIA  DEPARTMENT  OF  CONSERVATION 
^^'"'M^ DIVISION  OF  MINES  AND  GEOLOGY 
1416  NINTH  STREET,  ROOM  1341 
SACRAMENTO,  CA  95814 


CONTENTS 


Page 


Preface vii 

Abstract ix 

Introduction  1 

Purpose  and  uses 1 

Value  of  map  compilations  2 

Base  Mop 2 

Source  data  2 

Acknowledgments 3 

Part  I 
Fault  Map  of  California 

Introduction  7 

Recognition  of  faulting  as  cause  of  eartliquakes 7 

Evolution  of  fault  maps  of  California 7 

First  fault  map  of  the  state — 1908 7 

Second  fault  map  of  California — 1922 - 9 

Faults  sfiown  on  Geologic  Map  of  California — 1938 10 

Combined  Wood  and  Jenkins  fault  map  of  tfie  southern  half  of  the  state — 1947 11 

Earthquake  Epicenter  and  Fault  Map  of  California — 1964 12 

Earthquake  Epicenter  Mop  of  California — 1978   12 

Small-scale  fault  maps  of  California 12 

Preliminary  Fault  and  Geologic  Map  of  California — 1973  14 

Fault  Map  of  California — 1975  edition  14 

Depiction  of  faults 15 

Fault  classification 15 

Fault  definitions 15 

Historic  faults,  earthquakes,  and  creep 16 

Earthquakes  with  surface  rupture 16 

Recorded  fault  creep  18 

Displaced  survey  lines  23 

Seismicity 23 

Quaternary  faults 24 

Identification 24 

Problems 24 

Plio-Pleistocene  boundary  controversy 26 

Major  Quaternary  faults   26 

Philosophy  of  conservatism    26 

Pre-Quoternory  faults  27 

Accuracy  of  fault  locations  27 

Offshore  structure  28 

Coast  Range  thrust  28 

Circular  fault  structures  28 

Future  changes  in  fault  depiction  29 

Fault  patterns  30 

Structural  provinces  30 

Predominant  fault  trends  defining  structural  provinces 31 

Major  structural  blocks  with  predominantly  northwest  faults 31 

Coast  Ranges  block 31 

Peninsular  Ranges  block 31 

Major  structural  block  having  predominantly  east-trending  faults 31 

Transverse  Ranges  block    31 

Santa  Ynez  and  Son  Gabriel  sub-blocks 31 

Banning  sub-block 31 

San  Bernardino  sub-block 31 

Pinto  Mountains  sub-block  31 

Major  structural  blocks  charocterized  by  northeast-trending  fault  boundaries  32 

Mojove  block  32 

Tehachapi  block  32 

iii 


Page 

Major  structural  blockj  charocterized  by  north-trending  faults  32 

Kern  Canyon  block 32 

Ponomint  and  Death  Valley  blocks  32 

Worner  block  33 

East  Sierra  block 33 

Cascade  block  33 

Gordo  block 33 

Major  structural  blocks  characterized  by  other  types  of  faults  33 

Sonoran  Desert  block 33 

Sierra  Nevada  block  33 

Klamath  block 33 

Modoc  block 33 

Coast  Ranges   sub-blocks 33 

Santo  Lucia  and  Gobilan  sub-blocks 33 

Son  Francisco  ond  Berkeley  sub-blocks 34 

Diablo  and  Great  Valley  sub-blocks  34 

Stonyford  sub-block  34 

Peninsular  Ranges    sub-blocks 34 

San  Clemente  and  Cotalina  sub-blocks  34 

Polos  Verdes  and  Inglewood-Son  Diego  sub-blocks 34 

Santa  Ana,  Riverside,  and  Son  Jacinto  sub-blocks   34 

Sub-blocks  within  the  Modoc  block 34 

Summary 34 

Fault  couples 35 

En  echelon  faults 35 

Regularity  of  fault  spacing 35 

Summary  on  fault  geometry 39 

Faulting  and  patterns  of  seismicity 39 

Relationship  of  epicenters  to  faults 39 

Relationship  of  surface  rupture  to  earthquake  magnitude 41 

Faults  with  recurring  earthquake  activity  41 

Patterns  of  seismicity 42 

Cautions  in  use  of  Fault  Map  of  California  for  land-use  planning 42 

Depiction  of  volcanoes 43 

Distribution  and  age  43 

Relation  of  volcanoes  to  faults 44 

Volcanic  hazards  44 

Depiction  of  thermal  springs  and  wells  45 

Temperoture 45 

Mode  of  occurrence  of  hot  springs 45 

Distribution  of  hot  springs 45 

Part  II 
Geologic  Map  of  California 

Introduction  51 

History  of  geologic  mops  of  California  51 

The  first  attempts 51 

Preliminary  Minerological  and  Geological  Map  of  the  State  of  California — 1891 51 

Geological  Mop  of  the  State  of  Colifornia — 1916  51 

Geological  Mop  of  California — 1938 52 

Geologic  Atlos  of  California— 1958-1969  52 

Two  smoll-scole  geologic  maps  of  California   (1966  and  1968)  54 

Geologic  Map  of  California — 1977 54 

History  of  the  project   54 

Uses  of  the  geologic  map 55 

Objectives  and  contents  56 

Representation  of  faults 56 

Representation  of  contacts  56 

Compilation  method 56 

Classification  of  rock  units  and  special  problems 58 

Colors,  patterns,  symbols  of  rock  units,  ond  mop  appearance  61 

Geologic  time  scale 66 

Volcanoes 66 

Botholiths  ond  plutons 66 

Offshore  geology 68 

References  cited  in  Parts  I  ond  II 69 

iv 


Part  III 
Appendices 

Page 
APPENDIX  A:      INDEX  TO  FAULT  NAMES  SHOWN  ON  THE  FAULT  MAP  OF  CALIFORNIA,  1975  EDITION 

Named  faults  shown 77 

Procedure  for  naming  faults 77 

Index  to  fault  names 78 

Supplemental  index  to  fault  names  80 

APPENDIX  B:     TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 

Data  used  and  acknowledgments 81 

Locating  thermal  springs  and  wells 81 

Tabulated  list  of  thermal  springs  and  wells 81 

References  cited  in  Appendix  B  1 17 

APPENDIX  C:      INDEX  TO  THE  GEOLOGIC  FORMATIONS  GROUPED  WITHIN  EACH  UNIT  PORTRAYED  ON 
THE  GEOLOGIC  MAP  OF    CALIFORNIA,  1977  EDITION 

Explanation 1 19 

Index 120 

APPENDIX  D:     SOURCE  DATA  INDEX 

How  to  use  this  index 125 

Other  references 125 

Indexes  to  published  geologic  maps 125 

Indexes  to  theses 125 

Explanation  of  maps 127 

Bibliography   (by  atlas  sheet)    128 


LIST  OF  ILLUSTRATIONS 
Figures 

Figure  1.      Increase  of  published  geologic  map  data  for  California 2 

Figure  2.     Theses  on  California  geology  1892-1976   (exclusive  of  topical  and  brood  regional  studies)  3 

Figure  3.      Bruce  Clark's  1930  map  of  California  showing  "principal  known  primary  faults" 13 

Figure  4.      Mop  of  California  and  adjacent  terrone  showing  major  Quaternary  faults  and  identifying  historic  fault  breaks,  occurrences 

of  fault  creep,  and  triggered  creep 19 

Figure  5.      Mop  showing  small-magnitude  earthquake  epicenters  reported  during  1975 25 

Figure  6.      Generalized  mop  of  the  Long  Volley-Mono  Craters  area  showing  location  of  faults 29 

Figure  7.      Numerous  short  NW  and  NE  conjugate  faults  characteristic  of  the  Panomint  and  Death  Valley  blocks 32 

Figure  8.      Diagonal  faults  formed  between  two  major  strike-slip  faults,  the  Son  Andreas  and  the  Rodgers  Creek-Heoldsburg  faults  ...  36 

Figure  9.      Diagonal  faults  formed  between  the  strike-slip  Son  Andreas  and  Son  Gabriel  faults 37 

Figure  10.  Diagonal  folds  formed  between  the  San  Andreas  and  Rinconada  faults  in  thin  sedimentary  cover  overlying  granitic 

basement  rocks  38 

Figure  11.   Fracture  zones  illustrated  by  Menard   (1955)  40 

Figure  12.   Part  of  a  tectonic  mop  of  the  world   (Condie,  1976)   including  the  same  area  illustrated  by  Menard 40 

Figure  13.   Alignment  of  Tertiary  volcanic  plugs  near  San  Luis  Obispo  along  a  line  of  weakness  presumed  to  be  on  ancient  fault 44 

Figure  14.    Relief  Mop  of  California  showing  geomorphic  provinces  48 

Figure  15.   Geologic  Legend   (generalized  description  of  rock  types)  62-63 

Figure  16.   State  index  map  showing  the  boundaries  of  the  individual  Geologic  Atlas  sheets  and  the  source  data  index  mops  in 

Appendix  D  126 


Page 

Tables 

Table  1.      Summory  of  published  foull  mops  of  Colifornia 14 

Table  2.      Comporison  of  various  commonly  used  fault  definitions 17 

Table  3.      Evidence  used  for  determining  fault  history  17 

Table  4.      Port  A.     Historic  surface  faulting  associated  v/ith  earthquakes  in  California  20 

Port  B.     Historic  surface  faulting  associated  with  earthquakes  in  Nevado  ond  Bajo  California 22 

Port  C.     California  faults  displaying  fault-creep  slippage  not  associated  with  earthquakes  22 

Part  D.     Triggered  creep  along  faults  associated  with  earthquakes  in  California  23 

Table  5.      California  seismic  record  for  75  years 41 

Table  6.     Observed  volcanic  events  in  California 44 

Table  7.      Springs  neor  boiling  point  temperature 46 

Table  8.      State  geologic  mops  of  California  52 

Table  9.     Geologic  otlos  of  California   (1 -.250,000  scale)  53 

Table  10.   Derived  legend  for  1:750,000  scale  Geologic  Mop  of  California 59-60 

Table  11.  Comparison  of  "American"  and  "International"  mop  colors  for  sedimentary  rocks 64 

Table  12.  Comparison  of  "American"  and  "International"  map  colors  for  plutonic  and  volcanic  rocks  64 

Table  13.   Patterns  used  on  Geologic  Mop  of  Colifornio 65 

Table  14.   Geologic  time  scale 67 

Table  15.   Botholifh,  plutons,  and  stocks  identified  on  the  1977  Geologic  Mop  of  California 68 


Plates  (in  pocket) 

Plate  lA.  Faults  shown  on  the  first  fault  mop  of  California.  From  Mop  No.  1  of  the  State  Earthquake  Investigation  Commission  report  on  the 
California  earthquake  of  April  18,1906  (Lowson  and  others,  1908) .  Fault  names  shown  in  quotation  marks  ore  from  the  text  of  1908 
report;  other  fault  names  were  added  from  current  usage. 

Plate  1 B.  H.  O.  Wood's  abridged  version  of  Lawson's  1908  fault  map  of  California,  showing  faults  and  "lines"  tentative!/  considered  by  Wood 
to  be  generatrices  of  earthquakes. 

Plate  IC.  Faults  shown  on  the  Fault  Map  of  California  compiled  by  B.  Willis  ond  H.  O.  Wood  and  published  by  the  Seismologlcal  Society 
of  America  in  1922  at  o  scale  of  1:506,880. 

Plate  ID.  Faults  shown  on  the  Geologic  Mop  of  California  published  in  1938  at  1:500,000  scole.  This  reduced  version,  showing  faults  only, 
includes  all  those  faults  shown  on  the  larger  scale  mop.  Faults  were  not  shown  by  name  on  the  original  mop,  but  have  been  identified 
on  this  plate. 

Plate  IE.  Foult  mop  of  southern  California  (here  slightly  generalized)  compiled  by  H.  O.  Wood.  Faults  were  taken  largely  from  the  1922 
Fault  Mop  of  Californio  and  the  1938  Geologic  Mop  of  California. 

Plate  2A.  Structural  provinces  of  California  determined  by  the  prominent  fault  patterns  and  characteristics  of  the  faults  they  contain  or 
bound. 

Plate  2B.    Parallelism  between  major  Quaternary  faults  and  regularity  of  fault  spacing. 

Plate  2C.  Relationship  of  earthquake  epicenters  to  faults  in  California.  Note  the  close  relationship  of  earthquakes  of  magnitude  6  and  greater 
to  the  major  Quaternary  faults. 

Plate  2D.  Eorthquoke  epicenters  of  mognitude  4  to  4.9,  showing  more  scatter  than  for  the  larger  earthquakes,  but  also  suggesting  certain 
areas  of  low  historic  seismicity. 


VI 


PREFACE 

This  bulletin  was  prepared  after  the  GEOLOGIC  MAP  OF  CALIFORNIA  was  published  in  1977.  The 
parts  dealing  with  hot  springs  and  wells,  and  with  source  data,  now  included  in  the  appendices  to 
this  bulletin,  were  prepared  in  draft  form  in  conjunction  with  the  FAULT  MAP  OF  CALIFORNIA 
published  in  1975.  Most  of  the  text  was  written  in  1978  and  a  first  draft  was  reviewed  at  that  time. 
After  several  delays  the  manuscript  was  approved  for  publication  in  1981. 

The  data  in  Appendix  B,  Tabulated  List  of  Thermal  Springs  and  Wells  have  been  incorporated  in  the 
U.S.  Geological  Survey  GEOTHERM  data  bank  and  later  the  California  Division  of  Mines  and 
Geology,  Geologic  Data  Mop  No.  4,  GEOTHERMAL  RESOURCES  OF  CALIFORNIA.  It  is  included  in 
this  bulletin  as  documentation  for  the  locations  of  thermal  springs  and  wells  shown  on  the  FAULT  MAP 
OF  CALIFORNIA,  WITH  LOCATIONS  OF  VOLCANOES,  THERMAL  SPRINGS  AND  THERMAL  WELLS, 
Geologic  Data  Map  No.   1. 

The  Source  Data  Index  (Appendix  D) ,  although  somewhat  outdated,  is  still  the  best  guide  to  the  most 
useful  and  available  areal  geologic  mapping  in  California  to  approximately  1972,  and  its  annotations 
indicate  the  sources  used  to  classify  the  recency  of  activity  of  faults  in  California.  The  Source  Data 
Index  also  contains  some  data  to  1975. 

This  bulletin  reviews  the  history  and  development  of  geologic  and  fault  maps  of  California.  The  author 
has  taken  this  opportunity  to  articulate  various  ideas  and  speculations  pertaining  to  the  geology  and 
structure  of  California  that  have  occurred  to  him  over  the  years  he  has  spent  compiling  maps  published 
by  the  California  Division  of  Mines  and  Geology. 


VII 


ABSTRACT 

The  latest  in  a  series  of  State  Geologic  Maps  of  California  was  published  in  1977,  and  a  Fault 
Map  of  California  was  published  in  1975.  Bulletin  201  attempts  to  put  these  maps  in  historical 
perspective  by  describing  in  chronological  order  the  earlier  state  maps  of  both  these  types.  The 
bulletin  explains  various  uses  for  these  maps  and  also  discusses  precautions  against  their  misuse. 

This  volume  is  divided  into  three  parts.  The  first  deals  with  the  Fault  Map  of  California.  The 
evolution  of  fault  maps  of  California  is  described  beginning  with  the  first  fault  map  of  the  state 
(published  in  1908),  and  ending  with  a  detailed  description  of  the  1975  Fault  Map  of  California. 
Emphasis  is  placed  on  historic  and  Quaternary  faults  and  the  criteria  used  to  classify  them.  Fault 
patterns  recognized  in  California  are  discussed,  and  structural  provinces  of  the  state,  as  defined 
by  predominant  fault  trends,  are  proposed.  The  hmitations  in  the  use  of  the  Fault  Map  of 
California  for  land-use  planning  are  reviewed.  Finally,  a  discussion  of  the  volcanoes  and  thermal 
springs  and  wells  that  are  plotted  on  the  Fault  Map  concludes  the  first  part  of  Bulletin  201. 

The  second  part  of  the  bulletin,  pertains  to  State  geologic  maps  of  California.  A  brief  historical 
account  of  early  geologic  maps  of  the  state  is  followed  by  a  discussion  of  the  1977  edition.  The 
objectives  and  contents  of  the  map  are  described,  and  considerable  explanation  is  given  to  the 
compilation  method  and  the  physical  apjjearance  of  the  map,  including  a  discussion  of  the  choice 
of  colors,  patterns,  and  symbols.  A  brief  explanation  of  batholiths  and  other  plutons,  as  well  as 
the  offshore  geology,  follows. 

The  third  part  of  the  bulletin  consists  of  reference  data  organized  in  four  appendices.  Appendix 
A  is  an  index  to  the  272  fault  names  shown  on  the  Fault  Map  of  Cahfomia.  In  addition,  a 
procedure  for  the  naming  of  faults  that  would  avoid  repetition  and  confusion  is  suggested. 

Appendix  B  consists  of  a  tabulated  hst  of  584  thermal  springs  and  wells,  organized  by  1°  x 
2°  State  Map  Sheet  units.  This  list  contains  location  and  temperature  data,  and  pertinent  refer- 
ences. For  the  thermal  wells,  total  depth  and  year  drilled  are  also  given.  The  location  of  each 
thermal  spring  and  well  is  shown  on  the  index  maps  to  the  source  data  in  Appendix  D. 

Appendix  C  is  an  index  to  the  over  1,000  geologic  formations  grouped  within  the  units 
portrayed  on  the  1977  Geologic  Map  of  California. 

Lastly,  Appendix  D  is  an  extensive  index  to  the  source  data  used  to  compile  the  Geologic  Map 
and  for  classifying  the  faults  on  the  Fault  Map.  This  index  is  keyed  to  28  maps  showing  in  detail 
the  area  covered  by  the  references  listed  in  the  bibliographies. 

Bulletin  201  consists  of  197  pages,  including  16  figures,  15  tables,  and  two  plates.  The  Bulletin 
was  designed  to  accompany  the  Fault  Map  of  California  (1975)  and  Geologic  Map  of  California 
(1977),  and  hopefully  will  enhance  the  usefulness  of  these  maps  by  providing  additional  explana- 
tion and  background  data. 


AN   EXPLANATORY  TEXT 

TO  ACCOMPANY  THE    1:750,000    SCALE 

FAULT  AND  GEOLOGIC   MAPS  OF  CALIFORNIA 


BY  CHARLES  W.  JENNINGS 


INTRODUCTION 

The  Fault  Map  of  California  (1975),  the  Geologic  Map  of 
California  (1977),  and  this  bulletin  culminate  nearly  ten  years 
of  extensive  research.  To  a  degree  these  maps  represent  the 
"state-of-the-art"  in  California  regional  geology.  They  supersede 
the  Prehminary  Fault  and  Geologic  Map  of  California  on  the 
same  1:750,000  scale,  published  by  the  California  Division  of 
Mines  and  Geology  in  1973. 

The  Geologic  Map  of  California  presents  an  overview  of  the 
geology  and  structure  of  the  state  with  sufficient  detail  to  be 
useful  for  many  purposes.  It  should  fill  the  need  for  a  modem 
geologic  wall  map  showing  the  distribution  of  the  major  rock 
types  and  the  major  structural  elements  of  the  state.  The  Fault 
Map  of  California,  on  the  other  hand,  emphasizes  fault  activity 
in  the  state  and  differentiates  faults  according  to  time  of  activity. 
The  fault  map  also  shows  the  locations  of  the  numerous  recent 
volcanoes  in  California  and  the  locations  of  all  known  thermal 
springs  and  wells. 

This  bulletin  was  prepared  to  accompany  the  Fault  Map  and 
the  Geologic  Map  and  is  intended  to  enhance  their  usefulness  by 
providing  additional  explanation.  This  report  also  describes  the 
historical  antecedents  of  these  two  maps,  the  latest  in  a  sequence 
of  state  geologic  maps  that  was  started  in  1891.  No  attempt  has 
been  made  to  write  a  comprehensive  "Geology  of  California" — 
so  much  is  now  known  and  the  problems  are  so  complex  that 
California  geology,  for  most  intents  and  purposes,  has  become 
the  field  of  specialists.  Nor  has  the  writer  attempted  to  summa- 
rize or  generalize  the  basic  facts  of  Cahfomia's  geologic  history 
because  at  least  two  effective  overviews  have  been  published  in 
recent  years;  G.B.  Oakeshott's  "California's  Changing  Land- 
scapes" (1971  and  1978),  and  Norris  and  Webb's  "Geology  of 
California"  (1976).  Readers  are  referred  to  these  texts,  as  start- 
ers, if  they  are  unfamiliar  with  the  geologic  setting  in  California. 
For  more  advanced  considerations  of  California  geology,  the 
recent  literature  abounds  with  outstanding  papers.  Some  of  the 
most  instructive  are  the  outgrowth  of  symposia  on  various  top- 
ics, or  field  trip  guides  to  specific  areas  within  the  state.  To  list 
these  would  require  much  space;  however,  the  reader  is  referred 
to  the  "References  Cited  in  Parts  I  and  11"  on  pages  69-74 
wherem  many  useful  papers  are  included. 

Bulletin  201  consists  of  two  main  parts  and  four  extensive 
appendices.  Part  I  is  a  detailed  explanation  of  the  Fault  Map  of 
California  and  Part  II  is  a  discussion  of  the  Geologic  Map  of 
California.  Part  III  contains  four  appendices:  ( 1 )  an  index  to  the 
faults  shown  on  the  1975  edition  of  the  Fault  Map,  (2)  a  tabulat- 
ed listing  of  data  for  the  thermal  springs  and  wells  depicted  on 
the  Fault  Map,  (3)  an  index  to  the  geologic  formations  grouped 
within  each  of  the  units  shown  on  the  Geologic  Map  of  Califor- 
nia, and  (4)  a  detailed  bibliography  keyed  to  27  index  maps 
identifying  all  of  the  source  data  used  to  compile  the  Geologic 
Map  and  Fault  Map. 


The  Geologic  Map  of  California  and  the  Fault  Map  of  Califor- 
nia are  syntheses  of  the  available  information  on  the  geology  and 
structure  of  California.  An  attempt  was  made  to  summarize  and 
incorporate  some  of  the  currently  accepted  conclusions  regard- 
ing the  geologic  evolution  of  California,  for  example,  depiction 
of  the  Coast  Range  thrust  fault  as  the  upper  boundary  of  a  late 
Mesozoic  subduction  zone;  however,  little  attempt  was  made  to 
devise  a  uniform  structural  interpretation  of  the  entire  state. 
Uniformity  is  certainly  desirable;  however,  it  was  believed  that 
to  achieve  it  on  a  map  of  a  state  as  large  and  complex  as  Califor- 
nia would  be  a  difficult  and  time-consuming  task  and  might  even 
prove  to  be  of  dubious  value.  It  was  decided,  therefore,  to  con- 
centrate more  intently  on  the  basic  data,  namely  the  distribution 
of  the  various  rock  units,  and  generally  to  use  the  structural 
interpretations  shown  by  the  authors  of  the  source  data. 

In  synthesizing  data  from  individual  maps,  an  attempt  was 
made  to  follow  the  field  geologist's  interpretation  as  closely  as 
possible,  but  in  order  to  harmonize  one  map  with  another,  it  was 
often  necessary  to  be  arbitrary  in  the  selection  of  what  is  most 
significant.  No  two  compilers  will  make  identical  decisions; 
however,  at  the  onset  of  this  project,  guidelines  were  established 
and  followed  by  all  those  who  assisted  in  the  compilation.  In  the 
final  map-synthesis,  the  writer  tried  to  view  the  state  as  a  whole 
and  tried  to  give  the  compilation  a  certain  balanced  judgment. 
Thus,  in  the  resulting  maps,  the  depiction  of  faults,  especially 
recent  faults,  was  considered  more  important  than  the  portrayal 
of  rock  types.  In  congested  areas,  faults  may  have  sometimes 
been  exaggerated  by  connecting  several  segments,  or  by  general- 
izing the  local  geology. 

Purpose  and  Uses 

The  primary  purpose  in  preparing  the  Geologic  Map  of  Cali- 
fornia was  to  show  clearly  the  regional  relationships  of  rock  and 
time-rock  units  in  California,  and  of  the  Fault  map  of  California, 
to  depict  the  faults  as  to  their  recency  of  movement.  The  maps 
summarize  up-to-date  geologic  information  on  California  for  use 
in  applied  and  theoretical  geology. 

These  are  multipurpose  maps.  The  Geologic  Map  portrays  the 
geologic  setting  of  mineral  deposits  of  California  and  can  be  used 
in  planning  mineral  resources  investigations.  It  is  helpful  in  mak- 
ing regional  land-use  plans,  soil  surveys,  and  in  locating  and 
planning  large-scale  civil  engineering  projects  such  as  roads, 
dams,  tunnels,  and  canals.  The  Fault  Map  is  an  inventory  of 
faults  in  the  state  and  can  be  useful  in  preliminary  earthquake 
hazard  evaluations.  A  preliminary  version  of  this  map  was  pub- 
lished to  aid  local  governments  in  preparation  of  seismic  safety 
elements  required  by  California  law  as  part  of  the  general  plans 
(or  master  plan)  for  cities  and  counties.  The  Fault  Map  is  also 
useful  as  a  guide  to  Quaternary  and  recent  volcanism  and  thus 
is  useful  in  consideration  of  possible  volcanic  hazards.  Lastly,  the 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


locations  of  thermal  springs  and  wells  shown  on  the  Fault  Map 
are  indications  of  abnormally  high  temperature  gradients  and 
are  useful  in  the  exploration  and  development  of  geothernial 
power.  The  Geologic  Map  of  California  and  the  Fault  Map  of 
California  are  also  useful  in  classrooms  for  those  teaching  and 
studying  geology,  seismology,  and  geophysics,  a.s  well  as  related 
fields  such  as  geography,  oceanography,  ecology,  and  soils. 

Value  of  Map  Compilations 

A  compilation  is  no  better  than  the  data  sources  from  which 
it  is  compiled,  which  usually  vary  from  detailed  to  general  maps. 
A  compilation,  however,  can  go  beyond  the  sco[)e  of  the  source 
maps  and  reveal  broader  relationships,  by  virtue  of  the  capability 
of  synthesizing  individual  areas  and  thereby  revealing  important 
regional  trends.  A  careful  synthesis  thus  reveals  new  concepts, 
which  because  of  their  magnitude,  may  be  more  important  than 
the  details. 

Base  Map 

The  base  map  used  on  the  Fault  Map  of  California  and  the 
Geologic  Map  of  California  is  a  reduction  of  the  two-sheet 
1:500,000  scale  Map  of  California  published  in  1970  by  the  U.S. 
Geological  Survey.  These  two  sheets  were  reduced  to  1:750,000 
scale  and  joined  to  make  a  single  map  4  '/:  by  5  feet.  The  use  of 
a  single  large-size  sheet  instead  of  two  separate  sheets  eliminated 
problems  in  registration  and  matching  of  colors  from  sheet  to 
sheet  and,  most  important  of  all,  allowed  the  faults,  geologic 
formations,  and  structures  to  be  displayed  with  uninterrupted 
continuity. 

The  base  map  indicates  county  boundaries  in  green;  cities  and 
towns,  highways  and  roads,  railroads,  and  the  township-and- 
range  boundaries  in  black;  and  rivers,  streams,  and  other  water 
features,  including  ocean  depth  curves  at  100  fathom  intervals, 
in  blue.  Contours,  at  500-foot  intervals  with  100-foot  supplemen- 
tary intervals,  are  shown  in  brown  on  the  Fault  Map  and  are 
available  on  the  Geologic  Map  (part  of  the  first  printing  of  the 
Geologic  Map  was  without  contours).  The  base  map  is  a  Lam- 
bert conformal  conic  projection,  based  on  standard  parallels  33° 
and  45°.  The  highways  shown  are  correct  to  1969. 

Source  Data 

In  a  state  as  large  and  geologically  complex  as  California,  the 
quality  and  accuracy  of  the  geologic  mapping  varies.  In  general, 
the  latest  information  available  was  used.  The  1:250,000  scale 
Geologic  Atlas  of  California  was  the  principal  source,  but  exten- 
sive revisions  were  made  and  nearly  900  new  references  were 
added,  approximately  30  percent  of  which  were  from  unpub- 
lished sources. 

The  continual  progress  and  rate  of  growth  in  preparation  of 
published  and  unpublished  geologic  maps  in  California  are 
shown  in  Figures  1  and  2. 

Among  the  unpublished  data,  besides  geologic  theses  and  dis- 
sertations, some  company  and  consultant  reports  arc  included 
and  unpublished  maps  by  geologists  of  the  California  Division 
of  Mines  and  Geology  and  other  Stale  and  Federal  agencies, 
especially  the  California  Department  of  Water  Resources,  and 
the  U.S.  Geological  Survey.  Extensive  reconnaissance  maps  of 
parts  of  the  northern  Coast  Ranges,  which  were  made  by  the 
Department  of  Water  Resources  in  connection  with  proposed 
dams  and  tunnel  routes,  were  very  useful  in  revising  the  Ukiah 
Sheet  area,  and  the  extensive  work  by  the  U.S.  Geological  Survey 


in  the  San  Francisco  Bay  Region  Environment  and  Resources 
I'lannmg  Study  was  invaluable  in  the  revision  of  several  Bay  area 
sheets. 

Unlike  the  extensive  mapping  done  by  the  staff  of  the  Division 
of  Mines  and  Geology  for  the  preparation  of  the  State  Geologic 
Atlas,  most  of  the  Division  maps  used  in  the  1:750,000  scale 
compilation  were  taken  from  projects  such  as  the  urban  mapping 
cooperative  projects  with  cities  and  counties  and  from  the  com- 
pletion of  15-minute  or  7 '/;-niinute  quadrangle  projects.  The 
preparation  of  a  totally  revised  1:250,000  scale  Death  Valley 
sheet  (Streitz  and  Stinson,  1977)  was  especially  useful,  and  in- 
deed, was  done  in  part  to  aid  the  1:750,000  scale  compilation. 
Work  done  by  the  Division  specifically  for  the  1:750,000  compi- 
lation included  extensive  photo-interpretation  of  Quaternary 
faults  in  northeastern  California  and  field  evaluations  of  selected 
faults  to  determine  their  extent  or  recency  of  movement. 

Preparation  of  the  1:750,000  scale  map  began  in  1969,  and 
revisions  were  added  to  keep  the  work  sheets  current  until  about 
1972.  An  extensive  review  of  the  product  was  then  undertaken 
with  the  help  of  many  geologists  both  inside  and  outside  the 
Division  of  Mines  and  Geology.  As  a  result,  numerous  changes 
and  additions  were  made  to  the  compilation.  After  1974,  while 
the  maps  were  being  drafted  for  publication,  no  attempt  was 
made  to  keep  the  compilation  current,  because  of  lack  of  time 
and  the  difficulties  of  making  piecemeal  revisions  of  areas  which 
had  already  been  drafted.  However,  some  later  data,  especially 
newly  recognized  faults,  or  data  affecting  the  fault  classification, 
were  incorporated.  The  offshore  area  was  the  largest  single  area 
thus  affected,  because  of  the  vast  amount  of  new  data  released 
by  the  U.S.  Geological  Survey.  All  reference  data  used  in  the 
compilation  are  indexed  by  atlas  sheets,  and  shown  m  Appendix 
D. 


278  GEOLOGIC   MAPS 


37     27      56     45     105   217    383  670 


■^-1270  — 

GEOLOGIC 

MAPS 


1850    60 


70      80      90     1900     10      20      30      40     50     I960   1970 
PUBLICATION   YEAR 


Figure  1.      Increase  of  published  geologic  mop  doto  for  Colifornio. 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


60 


55 


50 


45 


V) 
UJ 

X 
H-   35 

li. 
O 

ir  30 

CD 

i25H 


20 


10 


p. 


niil 


XL 


Jl 


in 


£1 


1892    95 


1900 


05 


10 


20 


25 


30  35 

YEAR 


40 


45 


50 


55 


60 


65 


70 


1975 


Figure  2.     Theses  on  California  geology  1892-1976   (exclusive  of  topical  and  broad  regional  studies). 


Acknowledgments 

The  Fault  Map  of  California  and  the  Geologic  Map  of  Califor- 
nia are  based  on  the  work  over  many  years  by  a  vast  array  of 
geologists  and  institutions.  In  a  way,  these  two  maps  represent 
about  150  years  of  geologic  exploration  and  mapping  since  Lieu- 
tenant Edward  Belcher  first  surveyed  the  "Port  of  San  Fran- 
cisco," which  became  in  1839  the  first  published  geologic  map 
of  any  part  of  California.  Acknowledgment  therefore  goes  to  all 
the  geologists  down  the  years  who  have  mapped  in  California, 
for  only  by  drawing  on  this  collective  body  of  knowledge  have 
we  arrived  at  our  present  level  of  understanding  of  the  state's 
rocks  and  structure. 

Within  the  Division  of  Mines  and  Geology,  the  writer  is  espe- 
cially grateful  to  R.G.  Strand  and  T.H.  Rogers  for  their  assist- 
ance in  compiling  and  revising  the  1:250,000  scale  work  sheets 
during  the  first  stages  in  the  preparation  of  the  compilation. 
M.C.  Stinson  in  the  later  stages  helped  revise  the  depiction  of 
selected  Quaternary  and  historic  faults,  and  J.L.  Burnett  pre- 
pared a  photogeologic  interpretation  of  Quaternary  faults  for  the 
northeastern  part  of  the  state.  J.E.  Kahle  provided  valuable  as- 


sistance in  the  location  of  historically  active  faults,  and  his  un- 
published catalog  of  "Earthquakes  with  Surface  Faulting  or 
Ground  Breaks  and  Creep  Events"  was  particularly  valuable.  R. 
Streitz  and  M.C.  Stinson  substantially  improved  the  representa- 
tion of  the  geology  in  the  Death  Valley  Sheet  area  by  the  prepara- 
tion of  a  new  compilation  of  this  sheet  (Streitz  and  Stinson, 
1977).  Robert  Switzer  assisted  in  the  interpretation  of  some  of 
the  latest  geologic  data  used  in  updating  the  compilations  and 
also  in  making  numerous  corrections  immediately  prior  to  sub- 
mittal of  the  maps  to  the  printer.  The  painstaking  task  of  color- 
ing the  preliminary  compilation,  photographic  prints  of  which 
were  used  in  the  reviewing  process,  was  done  by  my  daughter, 
Marcia  Jennings. 

The  compilations  benefited  greatly  by  the  comments  and  new 
data  generously  provided  during  careful  review  of  this  map  by 
members  of  numerous  federal  and  state  agencies,  as  well  as 
independent  geologists  familiar  with  California  geology.  At  the 
risk  of  appearing  partial,  I  would  like  to  mention  the  following 
geologists  who  made  particularly  constructive  suggestions  or 
contributed  new  data  covering  large  areas  of  the  state;  E.H. 
Bailey,  E.E.  Brabb,  T.W.  Dibblee,  Jr.,  P.E.  Hotz.  W  P.  Irwin, 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


R.D.  Nason.  H.C.  Wagner,  CM  Wentwonh,  and  J.I  Ziony,  all 
of  the  U.S.  Geological  Survey;  Professors  C.R.  Allen,  California 
Institute  of  Technology;  J.C.  Crowell,  University  of  California, 
Santa  Barbara;  C.A.  Hall.  University  of  California,  Los  Angeles; 
B.M.  Page,  Stanford  University;  C.  Wahrhaftig,  University  of 
California,  Berkeley;  and  ML.  Hill  and  A.O.  Woodford,  Po- 
mona College,  Claremont,  California.  To  all  these  geologists  and 
many  other  unnamed  contributors,  the  State  is  especially  grate- 
ful. 

Of  all  the  individual  contributors  to  the  geologic  mapping  of 
California,  surely  Thomas  W.  Dibblee,  Jr.  warrants  special  rec- 
ognition and  appreciation.  A  vertiable  one-man  geological  sur- 
vey, he  mapped  and  published  more  than  eighty-four  15-minute 
and  thirty-five  7  '  .-minute  quadrangles.  In  addition,  Mr.  Dibblee 
has  numerous  geologic  quadrangles  that  he  has  mapped  but  not 
published. 

The  immense  task  of  scribing  and  preparing  the  plates  for 
publication  was  e.xpertly  done  by  R.R.  Moar,  R.T.  Boylan,  and 
R.A.  Switzer  of  the  Division.  The  Fault  Map  of  California  and 
The  Geologic  Map  of  California  could  not  have  become  a  reality 
without  the  ready  help  of  Merl  Smith,  Publications  Supervisor 
of  the  California  Division  of  Mines  and  Geology.  His  sage  advice 
in  lithographic  matters  and  his  assistance  in  obtaining  the  type 
of  map  we  desired  are  especially  recognized. 


The  maps  were  printed  by  the  Williams  and  Heintz  Map 
Corporation  of  Washington  D.C.,  under  the  masterful  supervi- 
sion of  William  Heintz.  Mr.  Heintz's  keen  interest,  cooperation, 
and  patience  were  demonstrated  time  after  time  while  we  experi- 
mented with  difTerent  colors,  shades,  patterns,  and  formats. 

In  the  preparation  of  this  manuscnpt,  two  of  the  four  appen- 
dices— the  Tabulated  List  of  Thermal  Springs  and  Thermal 
Wells  and  the  Source  Data  Index — could  not  have  been  possible 
without  the  extensive  help  of  John  Sackett,  Duane  McClure, 
Melvin  Stinson,  and  Robert  Switzer,  who  plotted  most  of  the 
thermal  springs  and  wells;  David  Peterson,  who  assisted  in  the 
preparation  of  the  source  data  index;  and  Robert  Switzer,  who 
drafted  most  of  the  plates.  The  initial  manuscript  was  edited  by 
Virginia  McDowell.  Dorothy  Hamilton  carefully  and  cheerfully 
typed  and  proof-read  this  manuscript,  including  all  the  extensive 
listings,  and  all  the  revisions. 

Special  thanks  are  due  B.W.  Troxel,  R.D.  Nason,  J.W.  Wil- 
liams, G.B.  Oakeshott,  D.L.  Wagner,  S.J.  Rice,  R.G.  Strand,  and 
C.R.  Real,  who  read  all  or  parts  of  the  manuscript  and  generous- 
ly aided  with  constructive  criticism. 

To  all  those  mentioned  above,  and  all  the  unnamed  individuals 
who  over  the  years  contributed  or  encouraged  the  preparation  of 
these  two  maps  and  this  bulletin,  I  wish  to  express  deepest  thanks 
and  appreciation. 


PART  I 
FAULT  MAP  OF  CALIFORNIA 


He  looketh  on  the  earth,  and  it  trembleth: 
He  toucheth  the  hills,  and  they  smoke. 


-Psalm  104 
Verse  32 


FAULT  MAP  OF  CALIFORNIA 


INTRODUCTION 

The  1975  Fault  Map  of  California  depicts  the  most  recent 
knowledge  on  the  distribution  and  nature  of  faults  in  California. 
It  also  indicates  as  factually  as  possible  the  activity  of  the  faults. 
Indications  of  the  degree  of  activity  on  faults  that  have  been 
mapped  in  the  state  are  based  on  the  recency  of  the  last  recog- 
nized movement. 

The  following  section  briefly  discusses  when  faulting  was 
recognized  as  the  principal  cause  of  earthquakes  and  how  faults 
were  considered  on  early  California  geologic  maps.  The  evolu- 
tion of  fault  maps  of  the  state  is  then  presented  before  going  into 
a  detailed  discussion  of  the  present  Fault  Map  of  California. 
Regional  fault  patterns  are  discussed,  and  the  writer  then  pre- 
sents his  concept  of  structural  provinces  of  California  based  on 
the  predominant  fault  directions  recognizable  in  the  state.  The 
relationship  of  faults  to  patterns  of  seismicity  is  discussed.  Last- 
ly, other  features  depicted  on  the  fault  map,  such  as  volcanoes 
and  thermal  springs  and  wells,  are  described  and  related  to  faults 
where  appropriate. 


RECOGNITION  OF  FAULTING  AS 
CAUSE  OF  EARTHQUAKES 

The  understanding  of  earthquakes  has  come  a  long  way  since 
Josiah  Whitney,  early  State  Geologist  of  California,  considered 
that  ground  fractures  associated  with  the  great  1872  Owens 
Valley  earthquake  were  of  small  importance.  The  prevailing 
thought  at  that  time  was  that  ground  fractures  were  the  result, 
not  the  cause,  of  earthquakes. 

As  a  matter  of  historical  interest,  it  was  not  until  1819,  in 
connection  with  the  Cutch,  India  earthquake  of  that  year,  that 
surface  faulting  itself  was  first  recognized  and  well  documented 
as  accompanying  an  earthquake.  In  California,  the  first  descrip- 
tions of  ground  displacements  associated  with  major  earth- 
quakes were  in  1836  on  the  Hayward  fault  and  in  1838  and  1857 
on  the  San  Andreas  fault.  However,  descriptions  of  ground  dis- 
placements during  these  earthquake-events  were  in  newspaper 
accounts  and  were  not  made  by  trained  observers.  In  fact,  it  was 
not  until  many  years  later  that  the  connections  between  these 
earthquakes  and  these  specific  faults  were  recognized  (Lawson, 
1908;  Louderback.  1947). 

In  California  it  probably  was  LeConte  who  first  proposed  the 
idea  of  faulting  as  a  cause  of  earthquakes.  In  his  article  "On  the 
Structure  and  Origin  of  Mountains,"  LeConte  (1878,  p.  101) 
considered  readjustment  along  the  fault  at  the  eastern  base  of  the 
Sierra  Nevada  as  the  cause  of  the  Owens  Valley  earthquake. 
Later,  LeConte  (1886,  p.  179)  stated  that  "With  every  readjust- 
ment and  increase  of  fault  [movement]  there  is  probably  an 
earthquake."  Worldwide,  according  to  Davison  (1927),  the  first 
person  to  attribute  an  earthquake  to  the  movement  along  a  fault 
probably  was  Rev.  Fisher  (1856)  in  his  description  of  the  Visp, 
Switzerland  earthquake. 

What  we  now  take  for  granted,  that  movement  along  faults  is 
the  cause  of  most  earthquakes,  did  not  become  generally  accept- 
ed until  after  the  1906  California  earthquake  and  H.F.  Reid's 
(1910)  precise  theoretical  formulation  of  the  elastic  rebound 
theory.  However,  the  English  engineer  Milne,  anticipated  Reid's 


elastic  rebound  theory  by  24  years  (but,  without  of  course,  the 
benefit  of  Reid's  rigorous  analysis  of  accurate  triangulation  sur- 
veys across  the  San  Andreas  fault): 

The  ground  is  broken  and  slips  either  up,  down,  or  side- 
ways, as  we  see  to  have  taken  place  in  the  production  of 
faults.  Here  we  get  distortion  in  the  direction  of  the  move- 
ment, and  waves  are  produced  by  the  elastic  force  of  the 
rock,  causing  it  to  spring  back  from  its  distorted  form 
(Milne,  1886,  p.  47). 

Though  faults  had  long  been  noted  in  older  rocks,  as  in  the 
case  of  displaced  beds,  early  geologic  maps  mostly  ignored  fault 
features  or  only  noted  an  occasional  fault.  Individual  U.S.  Geo- 
logical Survey  folios  for  California  (from  1894  to  1914)  show  no 
faults,  or  at  most  two  or  three  on  a  folio  map  before  1909. 
Fairbank's  San  Luis  Folio  (1904)  shows  several  faults  on  a  cross 
section,  but  the  faults  are  not  shown  on  his  geologic  map. 
However,  it  appears  to  have  been  early  U.S.  Geological  Survey 
policy  not  to  show  faults  on  the  folio  maps  even  if  the  geologists 
had  mapped  them  as  Fairbanks  had  done  (Olaf  P.  Jenkins, 
personal  communication,  1957).  In  1909,  the  Santa  Cruz  foho 
by  Branner,  Newsom,  and  Arnold  was  published,  and  it  dis- 
played many  faults.  Perhaps  the  Geological  Survey  changed  its 
policy  for  this  folio  because  the  area  it  maps  blankets  a  segment 
of  the  San  Andreas  fault  zone,  the  importance  of  which  had  been 
dramatically  demonstrated  by  the  1906  California  earthquake. 
The  San  Francisco  foho  by  A.C.  Lawson,  published  in  1914,  also 
portrayed  many  faults  on  the  maps  and  on  the  cross  sections. 
However,  no  faults  are  shown  on  Lawson's  map  of  the  San 
Francisco  Peninsula,  published  in  the  15th  Annual  Report  of  the 
U.S.  Geological  Survey  (1893-94),  although  in  the  text  the  San 
Andreas  and  other  faults  are  discussed  at  considerable  length. 

A  perusal  of  other  early  geologic  maps  of  areas  in  California 
also  reveals  few  mapped  faults.  The  earliest  volumes  of  the  Uni- 
versity of  California  Publications  in  Geology  show  but  few 
faults,  albeit  more  than  on  the  early  U.S.  Geological  Survey 
folios.  Apparently,  in  early  geologic  mapping  more  attention  was 
given  to  plotting  the  rock  distribution  than  in  trying  to  resolve 
geologic  structure. 


EVOLUTION  OF  FAULT  MAPS 
OF  CALIFORNIA 

First  Fault  Map  of  the  State — 1908 

The  atlas  of  the  State  Earthquake  Investigation  Commission 
report  (Lawson  and  others,  1908)  contains  a  map  of  California 
and  the  adjacent  states,  showing  the  more  important  known 
faults.  This  report  and  atlas  were  the  result  of  the  monumental 
investigation  of  the  1906  California  earthquake  which  did  such 
heavy  damage  in  north  coastal  California.  The  fault  map  in  the 
atlas  is  the  first  attempt  to  depict  faults  in  California  statewide 
(Lawson  and  others,  1908,  p.  346).  The  scale  of  the  map  is 
approximately  1  inch  equal  to  30  miles,  and  the  title  is:  "Geo- 
morphic  Map  of  California  and  Nevada  with  portions  of  Oregon 
and  Idaho  showing  the  diastrophic  character  of  the  relief,  the 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


steep  descent  from  the  sub-continental  shelf  to  the  floor  of  the 
Pacific,  and  the  more  important  faults" — a  cumbersome  but 
accurate  description  of  the  map.  Plate  lA  (pocket, herein)  is  a 
reduced  version  of  this  map  identifying  the  faults  described  in 
the  Lawson  report. 

Lawson's  map  is  very  interesting,  for  some  of  the  faults  shown 
on  it  were  subsequently,  and  mistakenly,  ignored  on  later  maps. 
On  Platel  A,  the  San  Andreas  fault  is  shown  extending  about  as 
far  south  as  San  Gregorio  Pass.  The  prominent  portion  of  the 
San  Andreas  fault  in  the  Mecca  Hills,  on  the  east  side  of  Coa- 
chella  Valley  and  on  the  east  side  of  Salton  Sea,  had  not  been 
discovered.  To  the  north,  however,  the  Shelter  Cove  fault  rup- 
ture of  1906  is  joined  to  the  San  Andreas  where  it  leaves  the 
mainland  at  Point  Arena.  This  speculative  connection,  concealed 
by  the  waters  of  the  ocean  and  requiring  a  broad  curve  in  the 
otherwise  long  straight  stretch  of  the  fault,  was  later  thought  to 
be  unreasonable,  and  the  segments  were  not  joined  together  on 
most  subsequent  maps.  This  lack  of  connection  persisted  until 
1967  when  sonic  profiling  at  sea  showed  that  the  San  Andreas 
fault  does  indeed  swing  back  to  shore  at  Shelter  Cove  (Curray 
and  Nason,  1967). 

The  Sierra  Nevada  fault  is  shown  on  Lawson's  map  as  being 
cut  off  at  its  southern  end  by  the  San  Andreas  fault  at  Gorman. 
Actually  the  Garlock  fault,  as  we  know  it  today,  intersects  the 
San  Andreas  fault  at  Gorman  and  also  intersects  the  Sierra 
Nevada  fault  northeast  of  the  town  of  Mojave.  The  Garlock  fault 
also  extends  far  eastward  into  the  southern  Death  Valley  area. 
The  Mojave  Desert  on  Lawson's  map  is,  as  we  might  expect, 
shown  as  being  devoid  of  faults,  for  little  of  the  desert  land  had 
been  explored  or  even  mapped  topographically  by  1908.  The 
northern  extent  of  the  Sierra  Nevada  fault  is  shown  as  an  almost 
continuous  trace  following  the  eastern  side  of  the  Sierra  Nevada 
crest  past  Lake  Tahoe  and  into  Plumas  County.  Modem  detailed 
mapping  shows  that  this  continuity  is  a  gross  oversimplification. 
Lawson  described  (p.  19)  a  "San  Gabriel  branch  of  the  San 
Andreas  fault"  in  southern  California  heading  westward  to  the 
ocean  at  Carpinteria.  This  fault  line  quite  accurately  connects 
what  are  now  known  as  the  Cucamonga,  Sierra  Madre,  Santa 
Susana,  and  Oakridge  faults.  What  is  mapped  as  the  San  Gabriel 
fault  today  lies  farther  north,  within  the  San  Gabriel  Range,  and 
then  heads  northwestward,  joining  the  San  Andreas  near  Gor- 
man. 

The  San  Jacinto  and  Elsinore  faults  are  crudely  depicted  on 
Lawson's  map,  but  the  Whittier  and  Malibu-Santa  Monica  faults 
are  quite  accurately  drawn. 

The  Kern  Canyon  fault  is  quite  accurately  located,  and  Law- 
son's  map,  unlike  several  succeeding  maps,  shows  its  full  north- 
em  and  southem  limits.  A  prominently  depicted  fault  west  of  the 
Kem  Canyon  fault  is  not  recognized  on  later  geologic  maps. 

Some  other  important  faults  in  the  southem  part  of  the  state 
that  were  mapf>ed  at  that  time  (at  least  in  part)  include  the  San 
Clemente  Island,  Santa  Ynez,  and  Nacimiento  faults. 

In  central  Califomia,  Lawson  (1908,  p.  19)  described  a  "Santa 
Lucia  fault"  as  "one  of  the  dominant  structural  lines  of  the  Coast 
Ranges  at  the  base  of  the  Santa  Lucia  Range  on  the  border  of 
Salinas  Valley."  Today  wc  know  the  northern  part  of  this  struc- 
tural line  as  the  King  City  fault.  Lawson  shows  this  fault  con- 
tinuing southeastward  to  San  Miguel.  This  part  is  incorrect 
according  to  modem  maps,  which  show  the  King  City  fault  as 
a  possible  continuation  of  the  Rinconada  fault  somewhat  farther 
to  the  west. 

In  the  San  Francisco  Bay  area,  the  Hayward  fault  is  correctly 
depicted,  but  its  north-bay  counterpart,  the  Rodgers  Creek- 
Healdsburg  fault,  is  missing.  However,  in  the  text,  Lawson 
(1908,  p.  17-18)  discusses  the  prolongation  of  the  "Haywards" 
fault  on  the  cast  side  of  the  Santa  Rosa  and  Russian  River  Valley 


northward  to  about  Cloverdale.  The  Calaveras  fault  is  not  well 
located,  but  the  shorter  Concord  and  Green  Valley  faults  are 
recognized.  Other  faults  correctly  mapf)ed  in  the  Bay  area  are 
the  San  Gregorio  fault  and  the  San  Bruno  fault.  A  strange  fault 
is  shown  directly  cross-cutting  the  San  Andreas  at  Pajaro  Gap 
and  is  described  by  Lawson  (p.  19)  as:  (1)  lying  approximately 
on  the  axis  of  the  geosyncline  of  Monterey  Bay,  (2)  transverse 
to  the  San  Andreas  and  intersectng  it,  and  (3)  near  the  place 
where  the  1906  surface  mpture  ceased. 

In  the  east  central  part  of  the  state,  the  White  Mountains  fault 
is  recognized  and  extended  as  far  south  as  the  Coso  Mountains. 
In  northem  Califomia,  the  Mother  Lode  faults  are  totally  ab- 
sent, but  probably  this  was  because  of  their  great  antiquity  and 
complexity.  The  Mother  Lode  fault  system  was  also  not  recog- 
nized on  several  subsequent  geologic  maps  of  the  state,  including 
the  1938  Geologic  Map  of  Califomia. 

The  fault  along  the  Chico  monocline  is  correctly  depicted 
from  its  southem  extent  near  Paradise,  but  it  is  drawn  too  far 
north.  By  the  time  the  second  fault  map  of  Califomia  was  pub- 
lished (Willis,  1922),  only  a  small  segment  of  this  fault  (east  of 
Red  BlufO  was  shown  (as  a  probable  fault) .  When  the  next  map 
(Jenkins,  1938)  was  published,  no  faults  were  shown  in  this  area. 
Mapping  for  the  Chico  Sheet  of  the  Geologic  Atlas  rediscovered 
these  faults  (Burnett,  1963).  Admittedly,  the  faults  only  show 
small  displacements,  but  their  continuity  and  abundance  on  the 
crest  of  the  monocline  are  very  striking  on  aenal  photos  and  are 
also  very  interesting  in  that  they  are  aligned  with  the  active 
Foothills  fault  system  to  the  southeast. 

Lawson  correctly  shows  the  Honey  Lake  fault  and  the  Sur- 
prise Valley  fault  in  northeastem  Califomia.  He  also  noted 
other  important  faults  in  this  part  of  the  state,  but  owing  to  lack 
of  adequate  maps  and  only  crude  reconnaissance  studies,  mis- 
connections  were  made.  The  same  is  true  of  the  northwestern 
part  of  the  state.  The  Orleans  fault  was  recognized  at  its 
northemmost  extent  (where  it  crosses  into  Oregon),  but  unhke 
the  simple  curving  line  depicted,  the  Orleans  fault  to  the  south 
is  now  known  to  take  a  much  more  circuitous  route,  befitting  a 
low-angle  thrust  fault,  before  continuing  for  many  miles  to  the 
southeast.  Actually  the  southem  two-thirds  of  this  fault,  about 
145  km  (90miles),  in  extremely  rugged  terrain,  is  quite  correctly 
located  on  Lawson's  map.  Just  west  of  this  fault,  is  O.H.  Her- 
shey's  "Redwood  Mountain"  fault  (Lawson  and  others,  1908,  p. 
17).  This  corresponds  to  the  South  Fork  Mountain  fault  of  the 
Geologic  Atlas. 

It  is  interesting  to  note  that  faults  were  not  depicted  on  any 
of  the  state  geologic  maps  preceding  Lawson's  1908  fault  map 
(see  Section  II,  herein),  nor  were  they  shown  on  the  1916  geo- 
logic map  of  Califomia.  G.A.  Waring  (1915),  in  describing  the 
springs  of  Califomia,  tried  to  show  the  relationship  of  springs  to 
faults  in  the  state,  but  a  note  on  his  map  indicates  that  the  faults 
were  taken  from  the  atlas  accompanying  the  1908  State  Earth- 
quake Investigation  Commission  report. 

In  1916,  Harry  O.  Wood,  in  a  study  of  faults  in  Califomia  as 
generators  of  earthquakes,  published  a  modified  version  of  Law- 
son's  1908  fault  map  (Wood,  1916).  This  map,  (Plate  IB,  here- 
in), confined  itself  to  Califomia,  but  omitted  a  number  of  valid 
faults  shown  on  Lawson's  map.  Wood  added  five  faults  or 
"lines"  which  he  considered  "generatrices  of  earthquakes."  Per- 
haps the  most  interesting  (and  prophetic)  was  his  so-called  "Eu- 
reka-Ukiah-San  Pablo  line."  This  appears  as  a  northwestward 
continuation  of  the  "Haywards"  fault  along  the  Rodgers  Creek, 
Healdsburg,  and  Maacama  faults,  extending  all  the  way  to  Eu- 
reka as  similarly  proposed  by  Herd  ( 1979)  and  Jennings  (here- 
in). Two  other  lines,  lying  offshore,  Wcxxi  referred  to  as  the 
Monterey  and  San  Pedro  submarine  fault  zones,  but  they  do  not 
correspond  to  any  of  the  offshore  faults  recognized  in  recent 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


years  by  acoustical  profiling.  Wood's  "Mare  Island-Nevada-Car- 
son line"  was  delineated  on  the  basis  of  rather  inaccurate  loca- 
tion of  earthquakes,  but  this  northeasterly  trend  does  not 
correspond  to  any  faults  known  in  the  surface  or  subsurface 
today.  It  is,  however,  parallel  in  part  to  the  subsurface  Stockton 
fault  across  the  Great  Valley.  The  fifth  feature  or  "line"  added 
by  Wood  is  the  "Great  Valley  axis"  lying  on  the  east  side  of  the 
Valley  and  approximately  bounding  the  Sierra  Nevada  block. 
"This  line,"  Wood  (1916,  p.  79)  states,  "is  not  considered  to 
delineate,  even  crudely,  any  fault  zone  or  chain  of  faults, — 
simply  to  bring  to  notice  the  tendency  for  certain  meizoseismal 
areas  to  cluster  in  line  along  the  Valley."  An  inspection  of  recent- 
ly published  earthquake  epicenter  maps,  however,  does  not  seem 
to  bear  out  Wood's  statement. 

Second  Fault  Map  of  California — 1922 

Bailey  Willis,  Professor  of  Geology  at  Stanford  University, 
and  H.O.  Wood,  Research  Associate  in  Seismology  of  the  Carne- 
gie Institution  of  Washington,  prepared  a  new  fault  map  of 
California  that  was  published  by  the  Seismological  Society  of 
America  in  1922  as  a  separate  publication.  The  map  was  com- 
piled at  1:506,880  scale  (1  inch  equals  8  miles).  A  reduced 
version  of  this  map  is  portrayed  in  Plate  IC  (in  pocket).  The 
Willis-Wood  map  is  evidence  of  the  growing  concern  about 
earthquakes  in  California;  Willis  (1923a)  reports  that  the  busi- 
nessmen of  San  Francisco  subscribed  $1,600  for  the  pubhcation 
of  the  map.  The  publication  of  the  map  was  followed  by  a  text 
(Willis,  1923b)  which  attempts  to  explain  the  rationale  in  com- 
piling the  faults  and  includes  a  brief  discussion  of  earthquakes 
and  their  relationship  to  faults.  (Wilhs'  strong  feeling  on  the 
importance  of  this  relationship  is  evident  in  the  opening  sentence 
of  his  text,  which  reads:  "Another  title,  and  perhaps  a  more 
obvious  one,  would  be  'Earthquake  Map  of  California.' ")  A 
large  part  of  the  report  is  also  given  to  description  of  various 
fault  features,  which  includes  a  particularly  long  treatment  of  the 
physiography  observed  along  the  San  Andreas  rift. 

Willis  was  responsible  for  compiling  the  northern  part  of  the 
state,  that  is,  the  part  north  of  San  Luis  Obispo,  while  Wood 
prepared  the  southern  part  (Willis,  1923,  p.  4).  An  attempt  was 
made  to  identify  "active  faults,"  "probably  active  faults,"  and 
"dead  faults."  However,  Willis'  criteria  for  classifying  faults 
were  not  the  same  as  Wood's  criteria.  Willis  considered  any  lault 
related  to  "a  growing  mountain"  as  a  reasonable  subject  for  an 
active  fault.  The  method,  as  he  explains,  was  based  on  observa- 
tion of  "mountain  forms"  and  the  interpreted  age  of  topographic 
surfaces  and  old  landscapes.  In  this  way,  he  classified  numerous 
mountains  as  being  bounded  by  active  faults.  Wood,  on  the  other 
hand,  considered  active  faults  as  those  that  are  known  to  have 
had  some  movement  during  historic  time  or  those  for  which 
there  is  evidence  of  recent  surface  dislocation.  The  map  has  two 
different  legends  for  the  three  sectional  sheets  of  the  state  to 
clarify  this  difference  in  interpretation  of  "active  faults."  The 
northwest  sheet  (which  was  entirely  the  work  of  Willis)  and  the 
southwest  sheet  (a  joint  effort)  contain  the  following  note  in  the 
legend: 

North  of  San  Luis  Obispo  faults  are  shown  as  active  if 
there  has  been  an  earthquake  during  historic  time  and  also 
wherever  they  define  valleys,  ridges,  or  ranges  which  are 
now  growing,  even  though  there  is  no  record  of  an  earth- 
quake on  that  particular  fault  during  historic  time. 

Consequently,  that  part  of  the  map  compiled  by  Willis  shows 
many  more  "active"  and  "probably  active"  faults  than  the  area 


compiled  by  Wood.  In  the  central  Coast  Ranges,  for  example, 
more  than  half  of  the  faults  are  shown  in  the  "active"  fault 
category.  The  legend  for  the  southeast  sheet  specifies  that  the 
"active  faults"  have  "earthquakes  recorded  on  lines  so  marked." 
Such  faults  indicated  include  the  Owens  Valley,  San  Andreas, 
Newport-Inglewood,  San  Jacinto,  and  parts  of  the  Elsinore  and 
Chino  faults.  The  "dead  faults"  are  designated  as  "not  known  to 
have  been  active  during  historic  time." 
Plate  IC  is  a  greatly  reduced  and  somewhat  generalized  version 
of  the  Willis  and  Wood  map,  but  it  accurately  represents  most 
of  the  faults  shown  on  the  1922  map.  In  many  ways  the  detail 
of  the  Willis  and  Wood  map  goes  far  beyond  Lawson's  1908 
map,  not  only  by  virtue  of  the  much  larger  scale,  but  more 
importantly  because,  during  the  14  years  following  the  Lawson 
map,  faults  and  the  problem  of  locating  and  understanding  them 
received  much  more  attention  than  before,  not  only  from  seis- 
mologists, but  also  from  geologists  searching  for  petroleum  and 
other  mineral  resources  and  from  geology  professors  and  their 
students  in  the  two  leading  academic  institutions  then  in  the 
state,  the  University  of  California  and  Stanford  University.  Un- 
fortunately, the  map  is  totally  blank  in  the  northernmost  part  of 
the  state  where  the  earlier  map  by  Lawson  showed  a  surprising 
amount  of  information  on  faults  that  has,  in  most  instances, 
withstood  the  test  of  time.  Willis  (1923,  p.  6)  justifies  the  ab- 
sence of  fault  delineation  north  of  the  latitude  of  Santa  Rosa  by 
explaining  that  topographic  maps  showing  sufficient  detail  and 
accuracy  of  the  landscape  did  not  exist  and  that,  therefore,  it  was 
impossible  to  follow  and  plot  the  faults  except  by  an  expenditure 
of  time  and  money  beyond  the  project's  means.  Willis  intention- 
ally disregarded  Lawson's  map.  (Perhaps  his  professional  feud 
with  Lawson  influenced  his  decision — this  is  suggested  by  his 
reference  to  the  map  in  Lawson's  Earthquake  Commission  re- 
port of  the  1906  earthquake  as  "a  map  of  the  principal  earth- 
quake faults  of  California  but  on  a  small  scale  and  not  complete 
enough  to  be  of  practical  use.") 

The  Willis  and  Wood  fault  classification  was  highly  interpre- 
tive and  commonly  went  beyond  the  data  at  hand.  The  attempt 
was  certainly  too  ambitious;  even  today,  distinguishing  between 
"active"  faults  and  "probably  active"  or  "dead"  faults  may  still 
be  beyond  our  means.  Nevertheless,  as  a  map  showing  the  loca- 
tion of  faults  known  in  the  state  at  that  time,  the  1922  map 
contains  a  wealth  of  information,  some  of  which  even  goes 
beyond  maps  published  later. 

The  remarkable  advancement  in  fault  mapping  represented  by 
Willis  and  Wood's  1922  fault  map  (Plate  IC)  becomes  readily 
apparent  when  it  is  compared  to  Lawson's  1908  map  (Plate  lA). 
In  the  Coast  Ranges  province,  for  example,  the  1922  map  shows 
numerous  faults — including  the  Rodgers  Creek-Healdsburg,  the 
Tolay,  the  Burdell  Mountain,  the  Pilarcitos,  the  Butano,  the  Ben 
Lomond,  the  Tesla,  the  Ortigalita,  the  Sur,  the  Tularcitos,  the 
Rinconada,  the  Ozena,  the  Little  Pine,  and  the  Pleito  faults — 
which  are  not  shown  on  the  earlier  map.  Also,  in  this  province, 
such  unnamed  faults  as  those  at  Dunnigan  Hills  and  in  Capay 
Valley  are  correctly  shown  on  the  1922  map  but  not  on  the 
earlier  one. 

Wilhs  and  Wood's  map  remains  an  informative  source  even 
today.  The  map  shows,  for  example,  an  "active  fault,  uncertainly 
located,"  lying  west  of  and  parallel  to  the  San  Andreas  fault  and 
coincident  with  the  straight  coastline  from  Bodega  to  Point 
Arena.  Today  the  existence  of  this  fault  is  a  likely  possibility, 
although  confirmation  of  it  is  still  lacking.  Another  interesting 
feature  shown,  in  a  critical  area,  is  the  Dry  Creek  fault  at  the 
Warm  Springs  dam  site.  According  to  Willis  and  Wood,  this  is 
an  "active,  well  located"  fault  which  connects  (to  the  north  as 
well  as  to  the  south)  with  "probable  faults,  character  and  loca- 
tion uncertain."  Today  part  of  this  fault  is  recognized  and  ap- 


10 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


pears  on  recent  U.S.  Geological  Survey  maps  (Blake  and  others, 
1974),  although  the  connection  between  the  Dry  Creek  fault  and 
the  active  Rodgers  Creek  fault,  which  is  shown  on  the  1922  map, 
has  not  been  verified.  To  the  north,  faults  arc  shown  in  Anderson 
Valley  and  along  the  Navarro  River — areas  which  since  1922 
have  not  been  cntically  evaluated  for  active  faults.  To  the  south, 
the  Quaternary  faults  now  recognized  at  San  Simeon  are  shown 
as  "active."  Interestingly,  an  "active  fault,  well  located"  is 
shown  in  the  San  Luis  Range,  at  Diablo  Canyon;  however,  recent 
investigations  in  this  area  have  not  confirmed  it.  The  Hayward, 
Calaveras,  and  parts  of  the  Nacimiento  fault  zones  are  shown 
much  as  they  have  been  mapped  since  then.  The  major  Quater- 
nary faults  in  the  central  and  southern  Coast  Ranges  as  we  now 
know  them  were  all  recognized  by  Willis  and  Wood,  perhaps 
with  the  exceptions  of  the  San  Juan  fault  and  the  full  extent  of 
the  Rinconada  fault  zone.  Of  course,  they  had  no  idea  of  the 
offshore  continuations  of  the  Seal  Cove-San  Gregorio-Palo  Colo- 
rado faults  or  the  Hosgri  fault  zone  lying  offshore  of  San  Luis 
Obisf>o  County.  Also,  they  did  not  always  recognize  certain 
Coast  Range  faults  as  being  young  faults,  for  some  are  shown  as 
"dead"  faults. 

Of  all  the  areas  shown  on  the  1922  map,  the  Transverse 
Ranges  and  the  Los  Angeles  basin  are  depicted  in  greatest  detail. 
Therefore,  the  1922  map  shows  numerous  faults  in  these  areas 
not  recognized  on  Lawson's  map,  including  the  northern  part  of 
the  San  Gabriel,  the  San  Francisquito  (site  of  the  St.  Francis 
Dam  failure),  the  Arroyo  Parida,  the  Red  Mountain,  the  Simi, 
the  Newport-Inglewood,  the  Palos  Verdes,  the  Cucamonga,  and 
the  Sierra  Madre  faults.  On  Willis  and  Wood's  map  the  Pacifico 
and  Santa  Ynez  faults  are  shown  more  accurately  than  on  Law- 
son's  map  (although  still  somewhat  crudely).  The  Liebre  and 
Clearwater  faults  are  recognized  but  incorrectly  joined  together. 
Willis  and  Wood  classify  the  faults  shown  in  the  Transverse 
Ranges  as  "dead"  with  the  exception  of  the  San  Andreas  fault 
(which  transects  the  Transverse  Ranges)  and  a  concealed  fault 
in  the  Alamo  area  along  San  Antonio  Creek  in  the  Santa  Maria 
basin.  This  latter  fault,  shown  as  an  "active  fault,  uncertainly 
located,"  is  not  recognized  by  later  mapping  in  the  area  (for 
example,  Woodring  and  Bramlelte,  1950)  and  therefore,  is  not 
shown  on  the  1975  Fault  Map  of  California.  The  fault  was 
apparently  based  on  a  doubtful  fault  hypothesized  by  Arnold 
and  Anderson  (1907)  and  was  probably  viewed  by  Willis  and 
Wood  as  the  cause  of  the  rather  severe  1902  and  1915  "Alamo" 
earthquakes.  Willis  and  Wood  likewise  classify  as  "dead"  all  the 
faults  in  the  Los  Angeles  basin,  with  the  exception  of  the  New- 
port-Inglewood and  Chino  faults. 

On  close  inspection,  one  can  make  out  the  San  Fernando  fault, 
on  which  the  disastrous  earthquake  of  1971  occurred.  However, 
Wood  has  identified  this  fault  as  a  "probable  fault,  character  and 
location  uncertain."  Nevertheless,  other  available  geologic  maps 
of  the  San  Fernando  area  prior  to  the  1 97 1  earthquake  show  little 
indication  of  a  San  Fernando  fault. 

In  the  Peninsular  Ranges  a  large  number  of  faults  are  shown. 
Among  these,  the  San  Jacinto,  Elsinore,  and  Whittier  faults  are 
better  defined  than  on  the  1908  fault  map.  The  Chino  fault  is 
depicted  as  a  "probable  active  fault,"  presumably  on  the  basis  of 
earthquake  epicenters.  A  probable  fault  is  correctly  shown  in  the 
upper  part  of  the  San  Diego  River,  but  many  other  "probable 
faults"  m  the  southern  California  batholith  are  today  considered 
to  be  joints  in  granitic  rtKksand  not  faults  (on  the  basis  of  a  close 
examination  showing  that  they  have  no  displacements).  The 
Crislianilos  fault  and  a  fault  m  Palm  Canyon  by  Palm  Springs 
arc  mapped  more  or  less  as  they  would  be  today. 

The  Mojave  Desert  is  shown  largely  devoid  of  faults.  The 
northern  boundary,  the  Garlock  fault,  is  recognized,  but  the  rest 


of  the  area  is  still  largely  unmapped  on  the  1922  map,  as  it  was 
in  Lawson's  time. 

North  of  the  Garlock  fault,  in  the  southern  Sierra  Nevada,  the 
Sierra  Nevada-Owens  Valley  faults  are  quite  accurately  located; 
the  Kern  Canyon  fault,  however,  is  incorrectly  shown  as  being 
shorter  than  depicted  by  Lawson;  and  the  White  Wolf  fault, 
which  ruptured  during  the  1952  Arvin-Tehachapi  earthquake,  is 
shown,  although  only  as  a  "dead,  well-located  fault."  liast  of  the 
Sierra,  only  a  part  of  the  Death  Valley,  Panamint,  and  Furnace 
Creek  faults  are  recognized.  Several  other  probable  faults  are 
shown  bounding  valleys  and  steep  mountain  fronts,  but  few  of 
these  have  been  confirmed  by  later  mapping. 

Like  Lawson's  map,  Willis  and  Wood's  map  shows  no  faults 
in  the  Mother  Lode  of  the  northern  and  central  Sierra  Nevada. 
This  is  interesting  because  a  close  examination  of  the  text  of 
some  of  the  U.S.  Geological  Survey  Mother  Lode  District  folios 
— for  example,  Ransome  (1900) — reveals  that  early  geologists 
were  aware  of  abundant  faults  in  the  area  and  that,  furthermore, 
some  believed  that  such  faults  were  possibly  still  active.  For 
example,  Ransome  (1900,  pp.  7-8)  writes: 

It  appears  highly  probable  that  much  of  the  movement 
which  has  affected  the  Sierra  Nevada  since  the  close  of 
Jurassic  time.. .has  resulted  in  the  linear  fissure  system  of 
the  Mother  Lode. 

The  dislocations  by  which  the  fissures  were  originally 
opened,  were  of  the  kind  known  as  thrust  faults.*  The 
present  structure  of  the  veins  shows  that  the  original  dis- 
placement was  followed  at  intervals  by  further  movement 
of  the  same  kind.  There  has  very  probably  been  subordi- 
nate displacement  of  reverse  character,  i.e.,  downward 
movement  of  the  hanging  wall  relative  to  the  foot  wall, 
producing  local  crushing  of  earlier-formed  veins,  and  re- 
sultmg  m  more  bodies  of  irregular  and  brecciated  charac- 
ter. There  is  evidence  that  this  latter  movement  is  still  in 
progress,  producing  the  gouges  and  slickensided  surfaces 
which  accompany  most  of  the  veins. 

The  fissures  which  the  veins  fill  were  formed  after  the 
post-Jurassic  folding  in  of  the  bed-rock  complex  and  after 
the  granitic  and  dioritic  intrusions.  They  have  probably 
continued  to  be  a  zone  of  movement  and  readjustment  ever 
since  their  first  dislocation,  and  such  movements  are  still 
in  progress. 

Why  the  Mother  Lode  faults  and  "fissures"  were  not  plotted 
on  the  folio  maps — whether  because  of  L'.S.  Geological  Survey 
policy  or  because  of  difficulties  in  mapping  the  structural  com- 
plexities— is  not  known.  In  any  event,  no  attempt  was  made  to 
show  this  important  and  extensive  fault  system,  even  in  a  most 
general  way,  on  any  regional  map  until  very  much  later  (see  p. 
11). 

Faults  Shown  on  Geologic  Map 
of  California— 1938 

A  far  more  accurate  depiction  of  faults  in  California  appears 
on  the  1938  Geologic  Map  of  California,  compiled  by  Olaf  P. 
Jenkins  at  a  scale  of  1:500,000.  This  outstanding  map  of  its  time, 
however,  followed  conventional  compilation  practice,  whereby 
all  faults  arc  treated  alike  and  historic  or  recently  active  faults 
are  not  distinguished  from  any  other  faults  shown  on  the  map. 

*Wc  would  refer  lo  ihese  Taults  today  a&  high-angle  reverse  faults. 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


11 


Plate  ID  is  a  reduced  version  of  the  1938 geologic  map  showing 
just  the  faults. 

Jenkins  did  not  refer  to  either  the  Lawson  fault  map  or  the 
Willis  and  Wood  map,  because  he  had  much  more  recent  data 
to  choose  from  for  most  parts  of  the  state.  In  some  ca.ses  he  could 
have  profited  by  selective  use  of  certain  faults  from  these  earlier 
fault  maps,  but  he  may  have  chosen  not  to  do  so  because  of 
possible  problems  with  harmonizing  the  earlier  mapped  faults 
with  the  geologic  contacts  he  was  depicting.  Jenkins  rightly 
could  not  mix  faults  and  geologic  contacts  without  additional 
field  evaluation,  for  which  he  had  neither  the  time  nor  the  funds. 
In  addition,  the  small  scale  of  the  Lawson  map  and  its  crude 
shaded-relief  base,  would  have  posed  serious  problems  in  some 
places  in  locating  features  on  the  larger  and  much  more  accurate 
1938  base  map. 

A  comparison  of  the  1938  map  with  the  1922  map  shows  that 
in  the  Coast  Ranges,  a  few  faults  that  were  not  shown  on  the 
1922  map  were  added,  but  others  were  omitted.  The  major 
Rodgers  Creek-Healdsburg  fault  is  missing,  but  the  less  pro- 
nounced Tolay  fault  is  shown.  The  Hayward  fault  falls  short  of 
San  Pablo  Bay  at  its  north  end.  The  Concord  fault  is  shown  as 
before,  but  its  counterpart  north  of  Suisun  Bay,  the  Green  Valley 
fault,  is  missing.  The  Palo  Colorado  and  Sur  faults  were  added, 
and  the  controversial  King  City  fault  was  omitted. 

Some  of  the  more  important  faults  in  the  northern  part  of  the 
state  that  the  1938  map  shows,  but  that  the  1922  map  does  not, 
include  the  Surprise  Valley  and  Honey  Lake  faults  and  the  faults 
of  the  Lake  Tahoe  graben.  Absent  from  the  1938  map  are  the 
series  of  faults  now  known  to  be  associated  with  the  Chico 
monocline,  which  are  indicated  on  the  1922  and  1908  maps. 

In  the  Transverse  Ranges,  the  Santa  Ynez  fault  is  better  de- 
fined, as  is  the  Clearwater,  but  the  Big  Pine  fault  still  had  not 
been  discovered.  The  San  Gabriel  fault  is  correctly  shown  at  its 
north  end,  disappearing  under  the  Frazier  Mountain  thrust  fault, 
and  the  south  end  is  correctly  shown  terminating  at  Mt.  Baldy. 
The  Malibu-Santa  Monica  fault  (shown  on  the  1922  map)  is  left 
off,  but  the  Raymond  Hill  fault  is  correctly  shown,  as  well  as  the 
Sierra  Madre-Cucamonga  faults.  A  vast  improvement  is  shown 
where  the  San  Andreas  splits  into  two  branches  and  becomes 
entwined  with  the  Banning  fault.  Also,  the  Pinto  Mountain  fault 
was  recognized  for  the  first  time,  and  the  Santa  Rosa  Island  and 
Santa  Cruz  Island  faults  were  added. 

On  the  1938  map  the  myriad  of  joints  shown  in  the  Peninsular 
Ranges  on  the  1922  map  have  been  omitted  although  the  Temes- 
cal  fault  has  been  preserved.  It  is  difficult  to  see  the  Newport- 
Inglewood  and  the  Palos  Verdes  faults,  which  are  there,  at  least 
in  part.  The  submarine  San  Clemente  Island  fault,  although 
known  at  the  time,  is  not  shown,  probably  because  no  faults  were 
shown  off  the  coast  on  the  1938  map  except  where  they  happened 
to  intersect  islands.  A  more  correct  orientation  of  the  Rose 
Canyon  fault  near  San  Diego  is  shown. 

Some  faults  are  shown  in  the  Mojave  Desert,  signaling  the 
beginning  of  recognition  of  a  strong  northwest  structural  grain, 
but  the  area  at  this  time  was  still  largely  unmapped. 

Very  little  of  the  configuration  of  the  Sierra  Nevada  fault 
shown  on  the  1922  map  is  shown  on  the  1938  map,  and  definition 
of  this  fault's  southern  end  is  almost  nonexistent.  The  faults  in 
Owens  Valley  (except  for  the  1872  break  at  Lone  Pine)  are  not 
as  completely  defined  as  on  the  1922  map.  The  northern  extent 
of  the  Kern  Canyon  fault,  correct  on  Lawson's  map,  falls  far 
short  on  the  1938  map.  Not  until  new  mapping  by  the  Division 
of  Mines  and  Geology  for  the  Fresno  Sheet  of  the  Geologic  Atlas 
was  this  fault  depicted  correctly  again  on  any  published  map 
(Matthews  and  Burnett,  1966). 

As  mentioned  in  a  preceding  section,  faults  in  the  Mother 
Lode  still  were  not  depicted.  By  this  time,  such  prominent  geolo- 


gists as  Knopf  (1929)  and  Ferguson  and  Gannett  (1932)  had 
not  only  recognized  the  abundant  fault  fissures  in  which  the 
gold-quartz  veins  were  emplaced,  but  also  had  talked  about  the 
existence  of  a  major  through-going  reverse  fault  bordering  the 
Mother  Lode  region  on  the  east.  These  faults  are  not  shown  on 
any  of  their  regional  maps  but  the  segments  which  lie  in  the  areas 
that  they  mapped  in  detail  are  shown.  Then,  in  1944,  King  and 
others  defined  a  highly  generalized  fault  trace  identified  as  the 
"Mother  Lode  mineralized  fault"  on  the  Tectonic  Map  of  the 
United  States.  Sixteen  years  later,  Lorin  Clark,  taking  the  find- 
ings of  the  early  gold-belt  workers  and  adding  his  detailed  obser- 
vations, prepared  a  regional  map  defining  the  Foothills  fault 
system  (Clark,  1960).  His  map  shows  the  Foothills  fault  system 
bounded  on  the  east  and  west  by  what  he  named  the  Melones 
fault  zone  and  the  Bear  Mountains  fault  zone,  respectively.  Sev- 
eral years  later  Lorin  Clark's  fault  system  appeared  on  the  Base- 
ment Rock  Map  of  the  United  States,  compiled  by  the  U.S. 
Geological  Survey  and  the  University  of  Texas  (Bayley  and 
Muehlberger,  1968) — although  mislabeled  as  the  "Mother  Love 
Belt"!  The  recency  of  fault  activity  on  faults  within  the  Melones 
fault  zone,  was  recognized  on  the  detailed  maps  by  Eric  and 
others,  (1955,  Plate  I  and  p.  27).  They  note  that  movement  took 
place  following  the  formation  of  the  Table  Mountain  Latite, 
suggesting  late  Pliocene  or  even  Pleistocene  activity.  Much  more 
recent  investigations  involving  trenching  (Alt  and  others,  1977) 
have  shown  that  Holocene  activity,  including  fault-displacement 
of  soils  has  taken  place.  Thus,  Ransome's  intuitive  observations 
77  years  ago  concerning  the  recency  of  fault  movement  men- 
tioned earlier,  have  proved  to  be  correct. 


Combined  Wood  and  Jenkins 

Fault  Map  of  The 

Southern  Half  of  the  State — 1947 

In  1947,  Harry  Wood  published  in  the  Bulletin  of  the  Seismo- 
logical  Society  of  America  a  paper  entitled  "Earthquakes  in 
Southern  California  with  Geologic  Relations."  In  it  he  tried  to 
correlate  earthquake  origins  in  California  with  geologic  faults. 
To  illustrate  his  ideas,  he  took  the  faults  shown  on  the  southern 
half  of  the  1938  Geologic  Map  of  California  and  supplemented 
it  with  faults  he  had  shown  in  the  same  area  on  the  1922  Fault 
Map  of  California.  Wood  also  added  certain  faults  not  known  by 
him  before  and  also  not  shown  on  Jenkins'  1938  map.  Wood, 
being  primarily  a  seismologist,  had  J. P.  Buwalda,  Professor  of 
Geology  at  the  California  Institute  of  Technology  (with  which 
Wood  was  then  associated),  critically  examine  the  resulting  fault 
map. The  published  map, from  which  Plate  IE  is  patterned,  was 
then  used  to  plot  epicenter  locations,  their  relation  to  the  faults 
serving  as  the  basis  for  the  paper.  Choosing  an  approach  to  fault 
classification  more  cautious  than  the  one  used  by  Willis  and 
Wood  on  the  1922  map,  with  its  "active,"  "probably  active,"  and 
"dead"  designations.  Wood  designates  the  faults  on  his  map  as 
"major  faults"  and  "other  faults,"  and  classifies  each  fault  as 
"well  located,"  "approximately  located,"  or  "uncertain." 

A  comparison  of  Wood's  1947  map  with  both  Jenkins'  1938 
map  and  Willis  and  Wood's  1922  map  shows  that  Wood  resur- 
rected possibly  significant  faults  from  the  1922  map  which  do 
not  appear  on  the  1938  map  and  also  that  he  added  some  faults 
that  do  not  appear  on  either  the  1938  or  the  1922  maps. 

Among  the  features  that  Wood  carried  over  from  the  1922 
map  but  that  do  not  appear  on  the  1938  map  are  the  King  City 
fault  and  faults  in  the  vicinity  of  Diablo  Canyon  and  Los 


12 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Alamos.'  The  joints  in  the  southern  California  balholith  east 
and  northeast  of  San  Diego  arc  retained  as  probable  faults,  but 
later  invesligaton;  have  found  no  evidence  for  displacement  on 
most  of  these  features  and  have  concluded  they  are  not  faults. 
The  fault  in  Palm  Canyon,  by  Palm  Springs,  which  the  1*538  map 
docs  not  show,  is  correctly  retained  from  the  l')22  map. 

Among  the  significant  omissions  on  the  1947  map  are  the  Big 
Pine  fault  and  the  San  Juan  fault — both  known  today  as  major 
Quaternary  faults.  The  configuration  of  the  Banning  and  Mis- 
sion Creek  faults  is  much  improved  in  the  manner  of  the  Jenkins' 
compilation,  but  a  significant  departure  exists  with  the  projected 
location  of  the  San  Andreas  fault  in  the  Salton  Sea  area  (which 
still  is  largely  a  matter  of  conjecture).  The  Inglewood  fault  is 
more  continuous  on  the  1947  map,  and  the  Palos  Verdes  fault 
is  shown  as  a  splinter  off  the  Inglewood  fault.  The  Imperial  fault, 
with  offset  along  some  64  km  (40  miles)  of  the  fault  trace  during 
the  May  1940  earthquake,  is  added.  Many  other  differences  in 
detail  occur  between  this  map  and  the  earlier  ones,  and  the  1947 
map  is  without  doubt  the  best  fault  map  of  the  southern  part  of 
the  state  published  up  to  that  time. 

Earthquake  Epicenter  and  Fault  Map 
of    California — 1964 

In  1964,  the  California  Department  of  Water  Resources  com- 
piled a  fault  map  of  California  using  mainly  the  published  and 
unpublished  1:250,000  scale  geologic  atlas  sheets  of  the  Califor- 
nia Division  of  Mines  and  Geology  (Hill  and  others,  1964). 
Although  this  map  depicts  faults,  its  primary  purpose  was  to 
show  epicenters,  and  the  bulk  of  the  report  accompanying  the 
map  consists  of  a  catalog  of  epicenters  (magnitude  4  and  greater, 
from  1934  to  1961 ).  The  faults  shown  were  divided  crudely  into 
"active  faults"  (after  C.F.  Richter's  textbook  "Elementary  Seis- 
mology," 1958),  and  "other  faults,  activity  not  ascertained." 
The  criteria  used  to  distinguish  between  these  two  classes  are  not 
indicated  on  the  map,  nor  are  they  explained  in  the  text.  All  the 
faults  on  this  map  are  shown  in  red  and,  according  to  the  legend, 
the  two  classes  of  faults  are  represented  by  two  different  line- 
widths;  unfortunately,  the  map  shows  a  range  of  line-widths, 
making  it  difficult  to  determine  in  some  cases  whether  the  fault 
was  meant  to  be  designated  as  active  or  not. 

The  map  was  published  on  three  sheets  at  1 :5(X),(X)0  scale  and 
is  included  in  the  pocket  of  the  California  Department  of  Water 
Resources  Bulletin  1 16-2.  The  map  and  report  were  prepared  as 
part  of  a  "crustal  strain  and  fault  movement  investigation,"  for 
use  in  planning  studies  and  tinal  design  stages  of  water  resources 
development  in  the  state.  The  report  recognized  the  usefulness 
of  such  data  in  preparing  estimates  on  the  probability  of  earth- 
quake occurrence  and  the  magnitude  of  the  damaging  earth- 
quake forces  that  should  be  anticipated  at  sites  proposed  for 
construction  of  authorized  State  water  facilities. 


Earthquake  Epicenter  Map 
of  California  — 1978 

The  California  Division  of  Mines  and  Geology  published  an 
earthquake  epicenter  map  of  California,  known  as  Map  Sheet 
39  (Real  and  others,  1978).  This  1:1,000,000  scale  map  shows 
all  epicenters  of  magnitude  4  or  greater  from  1900  through  1974. 
Faults  shown  on  the  map  arc  reduced  from  the  Division's  1975 
Fault  Map  of  California   The  map,  which  represents  all  faults 


with  thin  blue  lines,  does  not  distinguish  among  the  faults  as  far 
as  recency  of  movement  is  concerned.  It  is  a  product  of  the 
Division's  Earthquake  Catalog  Program.  A  short  text  is  included 
on  the  face  of  the  map. 

Small-Scale  Fault  Maps  of  California 

Several  page-size  and  smaller  outline  maps  specifically  show- 
ing the  major  and/or  active  faults  of  the  state  have  been  pub- 
lished over  the  years.  Some  of  the  more  noteworthy  ones  are 
listed  below: 

•  Richter,  C.F.,  1958,  Elementary  seismology,  W.H.  Free- 
man and  Co.,  and  Francisco,  p.  441  (Figure  27-3). 

•  Dickinson,  W.R.,  and  Grantz,  A.,  1968,  Historically  and 
recently  active  faults  of  the  California  region, /n  Proceedings 
of  conference  on  geologic  problems  of  San  Andreas  fault 
system:  Stanford  University  Publications  in  the  Geological 
Sciences,  v.  XI,  (map  and  list  following  p.  374). 

•  U.S.  Geological  Survey,  1970,  Active  faults  of  California, 
(map  and  text,  p.  15),  information  pamphlet  (revised  and 
updated  periodically;  latest  revision,  1974). 


The  scale  of  these  maps  and  the  grossly  simplified  bases  used, 
however,  make  it  almost  impossible  to  locate  the  faults  except  in 
the  most  general  way. 

In  addition  to  the  small-scale  maps  discussed  above  (faults  of 
which  are  almost  all  well  documented),  an  interesting  fault  map 
of  the  state,  particularly  of  the  Coast  Ranges,  was  published  by 
Bruce  Clark  in  the  Bulletin  of  the  Geological  Society  of  America 
(1930).  Clark,  a  Professor  of  Paleontology  at  the  University  of 
California,  Berkeley,  was  intrigued  with  the  tectonics  of  the 
Coast  Ranges,  which  he  interpreted  as  a  complex  series  of  fault- 
ed blocks.  To  illustrate  his  ideas  he  prepared  a  map  of  what  he 
considered  to  be  the  "pnncipai  known  primary  faults"  in  the 
Coast  Ranges  (Figure  3). 

As  was  common  in  those  days,  Clark  mterpreted  the  faults  in 
the  Coast  Ranges,  not  as  large-scale  strike-slip  faults,  as  we  do 
today,  but  as  bounding  a  series  of  raised  and  depressed  blocks. 
Clark  indicates  in  his  text  that  the  data  for  his  map  came  from 
various  published  and  unpublished  maps  and  that  a  large  num- 
ber of  the  fault  lines  were  studied  in  the  field  by  either  himself 
or  his  assistant  James  Fox.  Clark  states  (p.  70)  that  "only  faults 
which  we  considered  definitely  proven,  by  either  direct  or  in- 
direct methods,  have  been  included."  Of  course,  "indirect  meth- 
ods" leaves  much  room  for  interpretations  that  may  not  always 
be  accepted  by  other  geologists.  A  close  look  at  the  map  shows, 
however,  that  solid  lines  represent  "accurate"  faults  and  that 
these  comprise  less  than  half  of  the  faults  shown  on  the  map. 
Dashed  and  dotted  lines  indicate  "approximate"  and  "buried" 
faults,  respectively,  and  most  of  these  must  have  been  deter- 
mined by  Clark's  "indirect"  methods.  Many  of  them,  in  light  of 
later  detailed  field  mapping,  have  been  modified  or  discredited, 
but  some  have  proved  to  be  correct  or  are  still  considered  possi- 
ble. For  example,  his  interpretation  of  a  Salinas  Valley  (his  no. 
10)  and  King  City  (no.  1 1)  faults  as  branches  of  the  San  An- 
dreas ( 1 )  has  not  held  up.  But  his  extension  of  the  unnamed  fault 
known  today  as  the  White  Wolf  fault  across  the  southern  San 
Joaquin  Valley  to  the  San  Emigdio  fault  (23)  was  substantiated 
in  a  dramatic  way  by  the  occasion  of  the  Arvin-Tehachapi  earth- 
quake of  1952  and  the  a.ssociated  ground  rupture.  In  like  man- 
ner, Clark's  northward  extraptilation  of  the  Hayward  fault  (3) 


•The  |j»i  AUntcM  fault  u  alio  najnrd  on  ui  MxompjinyinK  map  by  Wood  (his  map  No.  4> .  here,  although  shown  concealed,  it  is  identified  as  one  of  the  major  faults  of  the  state  Perhaps 
thu  tuipectr<l  fault  svai  given  nich  prominmce  on  the  basil  of  the  significant  earthquakes  reported  in  the  vicinity  of  L^os  Alamos  in  1902  and  1915. 


1P85 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


13 


Figure  3 


Bruce  Clork's  1930  mop  of  Colifornio  showing  "principol  known  primary  foults".   [From  Geological  Society  America  Bulletin,   V.  41,  pi. 


161. 


14 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


into  Marin  and  Sonoma  counties  is  recognized  today,  although 
his  northernmost  arcuate  extension  into  Mendocino  County  may 
not  exist,  or  if  it  does,  at  least  not  as  part  of  the  same  Hayward- 
Rodgers  Creek-Healdsburg-Maacama  fault  trend  we  know  to- 
day. 

As  an  interesting  sidelight  we  might  point  out  that  what  is  now 
known  as  the  South  Branch  Garlock  fault  was  earlier  known  as 
the  Antelope  fault  (57).  Note  also  that  Clark's  Sisquoc  fault 
(34)  extrapolation  to  the  San  Luis  Hills  area  across  the  Santa 
Maria  Valley  resembles  Clarence  Hall's  east-side  bounding  fault 
of  his  proposed  Lompoc-Santa  Maria  pull-apart  basin  (Hall, 
1978).  The  reader  can  make  other  interesting  compansons  with 
earlier  and  later  fault  maps  illustrated  in  this  bulletin. 

Preliminary  Fault  and  Geologic  Map 
of  California — 1973 

As  an  integral  part  of  the  new  1:750,000  scale  Geologic  Map 
of  California,  which  was  planned  in  1965,  the  writer  proposed 
that  faults  be  emphasized  and  that  relatively  recent  faults  (those 
with  known  historical  movement  or  with  known  offset  of  Qua- 
ternary beds)  be  appropriately  indicated.  This  innovation  in 
depicting  faults  was  designed  to  help  satisfy  the  numerous  re- 
quests the  Division  was  receiving  for  a  map  showing  the  "earth- 
quake faults  in  the  state."  Thus  a  three-fold  fault  classification 
system,  based  on  recency  of  movement,  was  devised  and  utilized. 
In  an  attempt  to  be  as  specific  as  possible  and  to  avoid  the 
problems  arising  from  various  definitions  and  understandings  of 
the  term  "active  fault,"  faults  were  subdivided  into  three  catego- 
ries, based  on  the  time-scale  universally  used  by  geologists  and 
seismologists.  It  was  felt  that  this  system  was  commensurate 
with  the  scale  of  the  map  used  and  was  also  realistic  within  the 
time-frame  considered  for  preparing  a  statewide  compilation. 
The  three  categories  of  faults  chosen  for  the  statewide  compila- 
tion were:  ( 1 )  faults  along  which  historic  displacement  has  oc- 
curred (red  color),  (2)  faults  having  Quaternary  displacement, 
but  without  an  historic  record  of  movement  (orange  color),  and 
(3)  faults  that  are  pre-Quatemary  in  age  or  for  which  no  Quater- 
nary movement  has  been  recognized  (black).  This  fault  classifi- 
cation system  made  this  the  first  statewide  map  to  depict  faults 
by  recognized  recency  of  movement. 


In  1971,  a  preliminary  version  of  the  geologic  map  including 
classified  faults  was  completed.  It  appeared  as  two  sheets  in  the 
pocket  of  a  limited  edition  of  a  report  financed  by  the  U.S. 
Department  of  Housing  and  Urban  Development  entitled  "Ur- 
ban Geology  Master  Plan  for  California"  (Bruer,  197f).*  This 
highly  preliminary  map  was  then  revised,  and  review  copies  were 
prepared  in  1972.  After  the  reviewing  process  was  completed  and 
changes  and  additions  were  made  to  the  compilation,  a  prelimi- 
nary version  of  the  map  was  prepared  and  published  rapidly  in 
order  to  satisfy  the  growing  demands  for  fault  information  by  the 
cities  and  counties  that  were  faced  with  the  preparation  of  a  new 
seismic  safety  element  for  their  General  Plans,  as  required  by  the 
State.  As  a  result,  Preliminary  Report  13,  "Preliminary  Fault 
and  Geologic  Map  of  the  State  of  California"  was  published  in 
1973. 

The  map  was  printed  on  two  sheets  at  1 :750,000  scale  ( 1  inch 
=  12  miles).  The  map  showed  faults  offshore  as  well  as  on  land. 
Special  symbols  and  notations  on  the  map  indicated:  (1)  seg- 
ments of  faults  with  observed  historic  surface  displacement,  (2) 
points  of  fault  creep  slippage,  (3)  direction  of  fault  dip,  (4) 
direction  of  relative  lateral  movement  along  faults,  and  (5)  rela- 
tive up  or  down  movement  of  individual  faults.  The  map  proved 
to  be  useful  not  only  to  planners  but  also  to  geologists  and 
seismologists,  engineers,  and  others  involved  in  assessing  the 
possibility  of  future  fault  activity  and  ground  rupture  in  various 
parts  of  the  state. 


FAULT  MAP  OF  CALIFORNIA 
—  1975    EDITION 

The  Preliminary  Fault  and  Geologic  Map  of  California,  1973, 
proved  to  be  in  such  great  demand  that  the  printed  supply  was 
soon  exhausted.  In  the  meantime,  the  fault  information  on  the 
preliminary  map  was  further  edited  for  a  new  edition,  and  new 
data  were  added  in  several  areas,  especially  offshore.  Then  the 
locations  of  some  584  thermal  springs  and  wells  were  added.  The 
resulting  new  edition  measured  about  1.4  by  1.5  meters  (4.5  by 
5  feet)  and  was  printed  in  six  colors.  Each  historic  fault,  shown 
as  a  red  line  on  the  map,  was  emphasized  with  a  narrow  pink 
band.  Among  the  Quaternary  faults,  shown  as  orange  lines,  pale 


*  In  this  lame  report,  a  page-size  provisioiial  fault  map  of  the  state  was  included  as  Figure  A-6  (original  compilation  scale  was  1:1,000,000) .  This  map.  compiled  by  J.E.  Kahle,  attempted 
to  document  the  type  and  kind  of  stirface  faiJting  associated  with  historic  ground  breaks. 

Tab/e  1.     Summary  of  published  fault  maps  of  California. 


TITLE 

SCALE 

TOPOGRAPHY 

COMPILER 

Map  of  faults  accompanying  State  Earthquake 

1  in.  =  30  mi. 

Shaded  relief 

Lawson  (1908) 

Commission  report  (Map  No.  1  in  Atlas) 

Fault  Map  of  California 

1:506.880 

Shaded  relief 

Willis  and  Wood 

(1  in.  =  8  mi.) 

(1922) 

Earthquake  epicenter  and  fault 

1:500.000 

500  foot 

Hill  and  others 

map  of  California 

(1  in.  =  8  mi.) 

contours 

(1964) 

State  of  California,  preliminary 

1:750,000 

No  topography 

Jennings  (1973) 

fault  and  geologic  map 

(1  in.  =  12  mi.) 

Fault  map  of  California 

1:750.000 

500  foot 

Jennings  (1975) 

(1  in.  =  12  mi.) 

contours 

Earthquake  epicenter  map 

1:1.000.000 

No  topography 

Real  and  others 

of  California  (on  fault  base) 

(1  in.  =  16  mi.) 

(1978) 

1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


15 


orange  bands  were  added  to  identify  the  major  Quaternary 
faults.  The  map  was  published  in  1975  in  a  new  series.  It  was 
designated  as  Geologic  Data  Map  No.  1,  and  entitled  "Fault 
Map  of  California,  with  Locations  of  Volcanoes,  Thermal 
Springs,  and  Thermal  Wells." 


Depiction  of  Faults 


Among  the  multitude  of  faults  shown  on  the  State  Fault  Map, 
many  have  lengths  of  tens  or  hundreds  of  kilometers,  and  cumu- 
lative displacements  of  kilometers  or  even  scores  of  kilometers. 
For  example,  there  is  considerable  evidence  to  postulate  hun- 
dreds of  kilometers  of  right-lateral  displacement  on  the  San  An- 
dreas fault  since  its  inception,  and  25  to  64  km  ( 16  to  40  miles) 
of  left-lateral  displacement  on  the  Garlock  fault.  Also,  we  know 
that  the  Sierra  Nevada  block  was  raised  several  thousand  meters 
during  the  late  Cenozoic  era.  In  addition,  it  appears  that,  as  a 
result  of  subduction,  rocks  of  the  Franciscan  Complex  have  been 
dragged  far  below  the  rocks  of  the  Great  Valley  Sequence  along 
the  Coast  Range  thrust. 

On  the  other  hand,  many  other  well-known  faults  have  rela- 
tively small  displacements,  even  though  the  fault  length  is  meas- 
urable in  tens  or  hundreds  of  kilometers.  Furthermore,  many  of 
the  faults  shown  on  the  Fault  Map  are  comparatively  minor. 
Some  geologists  have  questioned  the  advisability  of  showing  mi- 
nor fault  features,  contending  that  they  contribute  little  informa- 
tion and  "clutter"  the  state  fault  map.  These  suggestions  are 
valid  for  certain  map  uses,  but  they  are  not  in  keeping  with  the 
original  map  objective  of  recording  all  fault  features  in  as  much 
detail  as  our  data  allowed  and  within  the  limits  of  legibility.  In 
this  way  the  map  would  serve  as  a  dependable  source  of  back- 
ground fault  data  for  the  state  as  a  whole,  which  could  be  eva- 
luated and  interpreted  in  the  future  by  more  detailed  studies. 

Further,  it  was  felt  that  by  recording  faithfully  all  mapped 
faults,  no  matter  how  short  or  isolated  they  might  appear,  future 
mapping  might  show  possible  fault  extensions  or  reveal  a  fault 
zone.  The  writer  has  been  impressed  ever  since  his  student  days 
that  there  are  many  faults  that  are  plainly  visible  in  underground 
mine  workings  that  cannot  be  detected  on  the  surface  even  after 
close  scrutiny.  Indeed,  the  discovery  of  many  previously  un- 
known faults  during  exploratory  trenching  shows  that  there  are 
many  more  faults  in  California  than  heretofore  expected. 

The  prime  users  of  such  a  statewide  inventory  of  faults  are 
engineering  geologists  and  others  who  have  responsibility  for 
siting  critical  structures  such  as  dams,  nuclear  power  plants,  and 
any  other  large,  potentially  hazardous  engineering  works. 
However,  land-use  planners  and  lay  people  concerned  with  ac- 
tive faults  and  earthquakes  are  also  interested  in  such  data.  The 
numerous  calls  and  inquiries  for  additional  information  about 
the  faults  shown  on  the  map  are  continual  testimony  to  the 
correctness  of  our  decision  to  show  faults  in  such  detail. 

In  addition  to  showing  the  location  and  extent  of  faults  with 
lines  color-coded  to  indicate  recency  of  activity,  the  map  indi- 
cates the  relative  movement  on  faults  (where  this  is  known)  with 
symbols.  Arrows  indicate  the  direction  of  relative  lateral  fault 
slippage;  the  letters  U  and  D  indicate  relative  vertical  (up  and 
down)  fault  slippage;  and  barbs  on  a  fault  indicate  the  upper 
plate  of  low-angle  reverse  or  thrust  fault.  An  arrow  at  right 
angles  to  the  fault  trace  indicates  the  direction  the  fault  surface 
dips.  Dates  placed  alongside  the  historic  faults  indicate  when 
earthquakes  occurred  that  were  accompanied  by  fault  rupturing, 
and  symbols  indicate  the  extent  of  the  earthquake  fault  rupture. 


Lastly,  red  dots  on  faults  indicate  where  fault  creep  has  been  or 
is  being  measured.  All  these  special  notations  are  described  in 
more  detail  below. 


Fault  Classification 

In  1965,  when  plans  were  being  made  for  a  1;750,000  scale 
geologic  map,  it  was  decided  to  show  more  than  the  usual  infor- 
mation about  faults  on  a  state  map  by  indicating  some  informa- 
tion about  each  fault's  history.  A  way  of  doing  this  would  be  to 
classify  faults  according  to  their  recency  of  activity.  At  that  time 
(as  at  present),  there  was  little  agreement  as  to  what  "active 
faults,"  "potentially  active  faults,"  and  "inactive  or  dead  faults" 
were,  so  these  terms  were  deliberately  avoided.*  In  their  place, 
a  fault  classification  system  was  developed  that  permitted  the 
presentation  of  fault  information  that  was  as  factual  as  the  geo- 
logic data  would  permit  and  that  still  included  some  indication 
of  the  relative  degree  of  fault  activity. 

The  three-fold  fault  classification  scheme  devised  distin- 
guishes faults  entirely  on  the  basis  of  recency  of  movement.  The 
first  category  includes  those  faults  on  which  recorded  displace- 
ment of  the  surface  of  the  earth  has  taken  place  in  historic  time 
during  earthquakes  or  by  fault  creep.  In  California,  historic  time 
is  about  two  hundred  years,  a  very  short  interval  indeed,  in  any 
geologic  sense.  The  historically  active  faults  are  shown  in  red 
with  a  pink  border  for  emphasis.  The  second  category  includes 
those  faults  that  have  displaced  Quaternary  deposits  (the  latest 
geologic  epoch,  which  includes  approximately  the  past  two  mil- 
lion years),  but  that  have  no  historic  record  of  surface  displace- 
ment. These  Quaternary  faults  are  shown  in  orange,  with  the 
major  faults  and  fault  zones  emphasized  by  a  pale  orange  band. 
Faults  in  the  third  category,  designated  by  heavy  black  lines  on 
the  map,  are  those  without  reccign/zec/ Quaternary  displacement. 
Probably  most  of  these  are  Pliocene  or  older;  but  many  are  of 
unknown  age,  and  some  of  these  may  have  had  unrecognized 
Quaternary  movement. 

The  pink  and  orange  bands  on  the  historic  and  major  Quater- 
nary faults  are  for  emphasis  only.  The  width  of  the  bands  has  no 
particular  significance.  They  are  not  to  be  confused  with  the 
special  studies  zones  of  the  Alquist-Priolo  Special  Studies  Zones 
Act,  which  requires  the  State  Geologist  to  delineate  zones  en- 
compassing all  potentially  and  recently  active  faults.  (These 
study  zones  maps  are  available  separately  from  the  California 
Division  of  Mines  and  Geology.) 

Fault  Definitions 

Before  proceeding  further,  it  will  be  useful  to  discuss  the 
definition  of  "fault"  and  such  terms  as  "active,"  "potentially 
active,"  and  "capable,"  because  these  terms  are  often  used  with- 
out a  clear  understanding  of  them.  In  recent  years,  especially 
since  the  siting  of  nuclear  power  plants,  consideration  of  poten- 
tially hazardous  faults  are  of  special  concern  (and  the  subject  of 
extensive  investigations,  reports,  and  hearings).  A  definition  of 
terms,  therefore,  is  essential  to  make  common  understanding 
possible,  not  only  among  geologists,  but  also  between  geologist 
and  lawyer  or  geologist  and  lay  people  involved  in  planning 
decisions.  Numerous  reports  contain  fault  definitions,  and  some 
of  the  most  pertinent  definitions  recently  have  been  summarized 
by  Slemmons  and  McKinney  (1977). 


■Miiny  dcniiitions  of  thoM:  lypt'5  uf  faults  have  been  published,  some  of  which  are  widely  andesen  legally  recognized.  Howes  er.  in  most  of  Ihese  cases  j  purpose  has  to  be  slated  first — for 
example,  construction  of  a  nuclear  power  plant,  a  large  dam.  or  a  hospital — Ix'fore  a  specific  fault  definition  can  be  applied.  This  problem  is  discussed  more  fully  in  the  following 
section. 


16 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


In  defining  the  term  "fault,"  geologists  have  no  significant 
disagreement;  the  various  defmilions  differ  only  in  the  elabora- 
tion. All  agree  in  defining  a  fault  as  a  tectonic  fracture*  or  break 
in  the  earth's  crust  along  which  displacement  (horizontal,  verti- 
cal, or  diagonal  movement)  has  taken  place.  In  elaborating, 
some  definitions  further  specify  ( 1 )  that  the  fracture  or  break 
may  be  either  a  discreet  surface  or  a  wide  zone  of  fractures;  (2) 
that  the  fault  may  be  a  result  of  repeated  displacements  which 
took  place  suddenly  or  very  slowly  as  a  result  of  creep  slippage; 
and  (3)  that  the  cumulative  displacement  may  be  measurable  in 
fractions  of  an  inch  (centimeters)  or  in  miles  (kilometers). 

The  use  of  the  designation  "active  fault"  on  a  map  in  this 
country  (and  probably  in  the  world)  began  with  the  publication 
of  the  Willis  and  Wood  "Fault  map  of  California"  (1922).  Un- 
fortunately, two  difTerent  sets  of  criteria  were  used  in  different 
parts  of  the  state  by  the  two  compilers.  Willis  designated  an 
"active  fault"  as  one  on  which  slip  is  likely  to  occur  and  a  "dead 
fault"  as  one  on  which  no  further  movement  may  be  expected. 
His  criteria  for  distinguishing  between  the  two,  however,  were 
quite  vague  and  his  active  faults  were  based  primarily  on  a 
"growing  mountains"  theory.  Wood,  who  compiled  the  southern 
part  of  the  state,  was  more  factual  and  designated  his  "active 
faults"  as  those  which  have  shown  activity  in  historic  time,  or 
which  have  physiographic  evidence  of  recent  surface  dislocation. 
Wood's  definition  of  an  active  fault  is  thus  based  on  observation 
and  has  survived  through  the  years  with  only  slight  modification. 
The  main  changes  to  Wood's  definition  have  been:  ( 1 )  the  addi- 
tion of  other  criteria,  principally  seismic,  for  identifying  active 
faults,  and  (2)  the  addition  of  a  spsecific  time  frame  since  the  last 
fault  movement  for  separating  "active"  from  "inactive"  faults 
(possible  because  of  the  modem  capability  of  deteriming  the 
time  of  movement  on  them). 

All  definitions  of  "active  faults"  in  common  use  imply  future 
movement  commonly  constituting  a  geologic  hazard.  In  recent 
years,  specialized  definitions  vary  according  to  the  type  of  struc- 
ture to  be  built  in  the  vicinity  of  a  fault  and  the  degree  of  risk 
acceptable  for  a  particular  type  of  structure.  The  most  conserva- 
tive definition  is  that  of  the  U.S.  Nuclear  Regulatory  Commis- 
sion (NRC,  formerly  U.S.  Atomic  Energy  Commission).  In 
defining  fault  activity  for  its  special  uses,  the  NRC  sought  to 
avoid  the  misunderstanding  that  might  arise  from  its  use  of  the 
term  "active"  by  using  the  term  "capable"  in  its  place.  A  "capa- 
ble fault"  is  defined  as  a  fault  that  exhibits  one  or  more  of  the 
following  characteristics:  ( 1 )  movement  at  or  near  the  ground 
surface  at  least  once  within  the  past  35,000  years,  or  movement 
of  a  recurring  nature  within  the  past  500,000  years;  (2)  mac- 
roseismicity  instrumentally  determined  with  records  of  sufficient 
precision  to  demonstrate  a  direct  relationship  with  the  fault;  (3) 
a  structural  relation  to  a  fault  deemed  "capable"  such  that  move- 
ment on  one  can  be  reasonably  expected  to  be  accompanied  by 
movement  on  the  other. 

In  California,  special  definitions  for  active  faults  were  devised 
to  implement  the  Alquist-Priolo  Special  Studies  Zones  Act  of 
1972,  which  regulates  development  and  construction  in  order  to 
avoid  the  hazard  of  surface  fault  rupture.  The  State  Mining  and 
Geology  Board  established  Policies  and  Criteria  in  accordance 
with  the  Act.  They  defined  an  "active  fault"  as  one  which  has 
"had  surface  displacement  within  Holocene  time  (about  the  last 
11,000  years)"  (Hart,  1980,  p.  21 ).  The  State  Geologist,  who  has 
the  responsibility  under  the  Alquist-Priolo  Act  to  delineate  spe- 
cial studies  zones  (i.e.,  regulatory  zones)  to  encompass  poten- 
tially hazardous  faults,  has  adopted  additional  definitions  based 
on  wording  in  the  Act.  A  "potentially  active  fault"  was  defined 
a-s  any  fault  that  "showed  evidence  of  surface  displacement  dur- 


ing Quaternary  time  (last  two  to  three  million  years)"  (Hart, 
1980,  p.  5).  On  the  1974  and  1976  editions  of  the  Special  Studies 
Zones  maps,  such  faults,  including  the  San  Andreas,  Calaveras, 
Hayward  and  San  Jacinto  faults  and  their  branches,  were  zoned 
unless  it  could  be  demonstrated  that  specific  fault  strands  were 
inactive  during  all  of  Holocene  time.  Because  of  the  large  num- 
ber of  potentially  active  faults  in  California,  the  State  Geologist 
adopted  additional  definitions  and  criteria  in  an  effort  to  limit 
zoning  to  only  those  faults  with  a  relatively  "high"  potential  for 
surface  rupture.  Thus,  the  term  "sufficiently  active"  was  defined 
as  a  fault  for  which  there  was  evidence  of  Holocene  surface 
displacement.  This  term  was  used  in  conjunction  with  the  term 
"well-defined,"  which  relates  to  the  ability  to  locate  a  Holocene 
fault  as  a  surface  or  near-surface  feature.  All  faults  zoned  since 
1977  have  had  to  meet  the  criteria  of  "sufficiently  active  and 
well-defined"  (Hart,  1980,  p.  5-6). 

Another  special  definition  is  used  by  the  U.S.  Water  and  Pow- 
er Resources  Services  (formerly  the  U.S.  Bureau  of  Reclama- 
tion) in  the  design  of  dams.  To  this  agency,  any  fault  exhibiting 
relative  displacement  within  the  past  100,000  years  is  an  active 
fault  (Slemmons  and  McKinney,  1977,  p.  19.) 

Table  2  is  a  summary  of  the  fault  definitions  in  common  use 
and  the  factors  on  which  they  are  based.  Each  of  these  definitions 
is  concerned  with  future  fault  activity  and  this  is  based  on  the 
recent  history  of  the  fault.  Depending  on  the  type  of  structure 
being  planned  and  the  acceptable  risk  to  be  taken,  the  definition 
of  an  active  fault  may  be  based  on  the  last  1 1,000  to  100,000 
years  or  on  repeated  movements  during  the  past  500,0(X)  years. 
The  recent  history  of  movement  on  a  fault  can  be  determined  by 
use  of  geological  or  historical  criteria.  A  summation  of  these 
criteria  is  presented  in  Table  3. 

Of  recent  concern  is  the  possibility  that  faults,  even  geological- 
ly ancient  ones  (that  is,  pre-Quatemary),  can  be  reactivated  by 
the  influences  of  man.  For  example,  there  are  now  several  au- 
thenticated cases  showing  that  the  filling  of  a  reservoir  can  in- 
duce fault  activity  and  earthquakes  of  significant  size.  In  this 
way,  what  may  have  been  considered  "inactive  faults"  can 
become  "active  faults." 

The  term  "active  fault"  is  best  avoided  altogether  when  seis- 
mic risk  is  not  a  consideration.  For  simply  describing  the  charac- 
teristics of  faults,  such  terms  as  "historic  fault,"  "Holocene 
fault,"  "Quaternary  fault,"  "pre-Quaternary  fault,"  or  "seismi- 
cally  active  fault"  are  preferable.  With  these  designations,  a 
project  geologist,  after  confirming  the  designation  of  a  fault,  can 
then  go  on  and  make  his  own  determination  of  its  activity  rela- 
tive to  the  type  of  structure  to  be  built  and  the  acceptable  risk. 

Historic  Faults,  Earthquakes,  and  Creep 

Faults  along  which  displacement  has  occurred  during  historic 
time  are  shown  in  red  on  the  Fault  Map  of  California.  A  fault 
was  classified  as  historic  if  it  had  ( 1 )  a  recorded  earthquake  with 
surface  rupture.  (2)  recorded  fault  creep,  or  (3)  displaced  sur- 
vey lines.  A  fourth  criterion  was  considered,  namely  seismicity, 
but  this  was  ultimately  rejected  for  the  1975  map  (for  reasons 
explained  in  a  later  section). 

Earthquakes  With  Surface  Rupture 

The  historic  record  of  earthquakes  in  California  goes  back 
slightly  more  than  200  years  to  the  Portola  expedition  of  1769, 
when  violent  earthquakes  were  felt  in  the  Los  Angeles  region  and 
recorded  in  the  diaries  of  these  explorers.  However,  no  record  of 


•A  Irctuuc  (ractuir  it  dulinKuutublr  from  nontpclonic  fraclum  »uch  us  %ul«idcncc  rruclur<■^.  IuiuUIkIc  (riKluro^.  el  cx-lcra,  by  huviiiK  ili  ongin  <l<i-p  iii  Ihf  <Mrlh 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


17 


Table  2.      Comparison  of  various  commonly  used  fault  definitions. 


Design 
structure 

Fault 
term 

Time  of  last  displacement  on  fault 

Other  criteria 

NRC 

(U.S.  Nulcear 

Regulatory 

Comm.)   1975 

Nuclear 

power 

plants 

Capable 

1)  at  least  once  within 
past  35,000  yrs.  or 

2)  two  or  more  times 
within  past  500,000  yrs. 

1)   Macro-seismicity  relatable  to  specific 

fault. 

2)Structural  relationship  to  a  capable 

fault  such  that  movement  on  one  could 

cause  movement  on  another. 

CDMG 
(Calif.  Div. 
Mines  & 
Geol.)  1976 

Structures 
for  human 
occupancy 

Active 

Within  Holocene 
(  11,000  yrs.) 

Potentially 
active 

During  Quaternary  (last 
2-3  million  years). 

USBR" 

U.S.   Bur,   Re- 
clamation) 1976 

Dams 

Active 

Within  past  100.000  yrs. 

New  Zealand 
Geol.  Survey 
1976 

Town 
planning 

Active 

Since  last  glaciation 
(50.000  yrs.)  or  repeated 
movement  in  last  500,000  yrs. 

Grading  Codes 
Board  (Assoc. 
Eng.  Geol.) 
1973 

Not  specified 

Active 

Historic. 

Potentially 
Active 

No  historic  evidence  but 
strong   evidence  of  geologically  re- 
cent activity. 

High 
Potential 

Holocene. 

a)  Ground  water  barrier 

or  anomaly  within  Holocene  deposits. 

b)  Related  earthquake  epicenters. 

Low 
Potential 

Pleistocene  (less  than 
1,000,000  yrs.). 

Louderback 
1950 

Not  specified 

Active 

Historic  or  Recent 
(i.e.  Holocene). 

Related  earthquake 
epicenters. 

Table  3.      Evidence  used  for  determining  fault  history. 


Criteria 

Evidence  For   Recent  Displacement 

Geological 

1)  Geomorphic  evidence  of  fresh  or  youthful  appearance  (e.g  ,  fault  scarps,  triangular  facets,  markedly  linear 
and  steep  mountain  fronts,  and  shutterndges.  i.e.,  ridges  blocking  normal  stream  drainage). 

2)  Alignment  of  horizontal  depressions  that  are  not  the  result  of  differential  erosion  (e.g.,  sag  ponds,  saddles, 
troughs,  valleys). 

3)  Displaced  or  deformed  deposits  of  Holocene  or  Pleistocene  age  (e.g.,  faulted  alluvium,  alluvial  fans,  terraces, 
and  other  recent  geologic  formations). 

4)  Offset  Holocene  or  Pleistocene  ridges  or  stream  courses  (offset  systematically  in  the  same  direction.) 

5)  Ground  water  barriers  in  alluvium   (often  marked  by  contrasts  in  vegetation  or  determined  by  well-log 
records). 

Historical 

Recorded  accounts  of: 

1)  actual  ground  breakage. 

2)  distributed  earthquake  damage  permitting  reasonable  reference  to  a  particular  fault. 

Criteria 

Evidence  For  Current  Displacement 

Geological 

1)  Creep  slippage. 

2)  Surface  features  in  modern  alluvium  or  in  soils  (e.g.,  open  fissures,  mole  tracks,  pressure  ridges). 

Seismological 
or  Geodetic 

1)  Alignment  of  earthquake  epicenters  including  microearthquakes  (  <M3.0) 

2)  Displaced  survey  lines. 

18 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


ground  displacemeni  was  reported  by  ihe  expedition  for  this 
event,  although  the  intensity  of  the  quake  at  their  camp  was 
considerable. 

As  far  as  can  be  ascertained,  the  first  record  of  ground  dis- 
placement in  California  was  associated  with  the  Hayward  fault 
during  the  earthquake  of  1836.  About  30  subsequent  earthquake 
events  have  occurred  in  California  that  have  well-documented 
ground  breakage.  These  events  are  listed  in  Table  4,  Part  A,  and 
are  shown  on  Figure  4  and  the  Fault  Map  of  California. 

During  the  l''52  Arvin-Tehachapi  earthquake,  many  wide- 
spread and  well-defined  surface  breaks  or  cracks  developed 
which  were  noi  part  of  the  causative  White  Wolf  fault.  These 
ground  breaks  were  the  result  of  ground  failures  during  the 
shaking  of  this  event.  Because  of  the  extensive  distribution  and 
possible  significance  of  the  cracks  to  future  land-use  planning, 
some  of  these  breaks  are  shown  on  the  Fault  Map.  Likewise, 
small  breaks  were  associated  with  the  1971  San  Fernando  earth- 
quake that  were  probably  due  to  severe  ground  shaking.  Some 
of  these  breaks  also  have  been  shown  on  the  map. 

It  should  be  noted  that  the  dates  of  the  earthquakes  associated 
with  fault  rupture  are  indicated  on  the  Fault  Map  of  California 
in  red.  Red  triangles  are  placed  along  the  historic  faults  to  indi- 
cate the  terminating  points  of  observed  surface  displacement. 
Most  of  these  points  are  well  established,  but  unfortunately,  the 
records  are  not  always  good  enough  to  know  for  certain  what  the 
extremities  were  in  the  case  of  several  earlier  earthquakes  having 
ground  ruptures.  Today,  when  an  earthquake  occurs,  numerous 
geologists  and  seismologists  swarm  into  the  area  to  study  and 
map  the  effects,  but  before  1906  the  relation  between  faulting 
and  earthquakes  was  not  recognized  and  little  or  no  attempt  was 
made  by  early-day  scientists  to  record  such  data.  For  example, 
Josiah  Whitney,  the  State  Geologist  of  California,  was  the  first 
scientist  on  the  scene  after  the  great  1 872  Owens  Valley  earth- 
quake, but  he  made  no  effort  to  record  the  ground  ruptures. 
Hence  the  full  extent  of  these  ruptures  is  still  imperfectly  known. 
What  is  known  has  been  learned  by  modem  interpretive  tech- 
niques. The  1872  scarps  at  the  few  populated  areas  where  the 
ground  ruptures  are  well  known  (because  of  reports  of  associat- 
ed damage)  were  observed,  and  low  sun  angle  aerial  photo- 
graphs were  scrutinized  closely  to  distinguish  scarps  with 
features  characteristic  of  the  known  1872  scarps  from  older, 
more  eroded  scarps  in  the  area. 

The  extent  of  the  ground  rupture  associated  with  the  1857 
earthquake  on  the  San  Andreas  fault  poses  still  another  problem. 
In  this  case,  the  accounts  of  rupture  were  based  on  newspaper 
reports  made  by  untrained  observers.  Thus  the  southern  end  of 
the  break  is  reported  in  two  different  places,  one  near  San  Ber- 
nardino and  the  other  in  the  Colorado  Desert.  A  study  of  the 
relative  youthfulness  of  fault  features  on  the  San  Andreas,  many 
of  which  are  still  preserved  in  this  semi-arid  climate  of  southern 
California,  suggests  that  the  southern  extent  of  the  1857  event 
was  at  Cajon  Pass  and  that  the  fault  features  traceable  into  the 
Colorado  Desert  should  be  attributed  to  some  earlier  pre-historic 
event.  The  northern  extent  of  the  1857  rupture  is  also  in  doubt 
because  of  vague  reports.  Attempts  to  reinterpret  its  northern 
limit  have  not  been  successful  because  of  subsequent  earthquakes 
and  fault  breaks  in  the  same  region. 

There  is  great  uncertainity  about  the  location  of  the  1852 
earthquake  ruptures  in  southern  California.  Newspaper  ac- 
counts of  this  event  describe  the  occurrence  in  a  sparsely  inhabit- 
ed Lockwood  Valley,  but  because  there  are  two  Lockwood 
Valleys  in  the  state  that  are  astride  major  fault  zones  (the  Big 
Pine  fault  and  the  Rinconada  fault),  there  is  considerable  uncer- 
tainty about  which  remote  area  suffered  the  reported  30  miles  of 
ground  breakage.  Until  recently,  the  Big  Pine  fault  was  believed 


to  be  the  site,  but  closer  scrutiny  suggests  that  the  fault  features 
along  the  Big  Pme  fault  are  probably  not  of  historic  origin. 

Ground  rupture  associated  with  the  1966  Truckee  earthquake 
in  the  Boca  Reservoir  area  north  of  Lake  Tahoe,  is  not  complete- 
ly understood.  The  area  is  dominated  by  northwest-trending 
faults,  but  the  concentration  of  ground  breakage  resulting  from 
this  earthquake  was  along  a  northeasterly  trending  zone  16  kilo- 
meters long.  This  suggests  that  it  may  be  related  to  a  subsurface 
northeast-trending  fault  (Kachadoorian  and  others,  1967). 
Whether  the  surface  earthquake  effects  mapped  on  and  adjacent 
to  this  probable  fault  were  due  to  tectonic  movement  or  to 
ground  shaking  could  not  be  determined  (Carter,  1966). 

The  San  Jacinto  fault  is  one  of  the  most  seismically  active 
faults  in  southern  California.  The  fault  has  a  record  of  historic 
fault  displacement  along  its  southernmost  portion;  for  example, 
breaks  were  associated  with  the  1968  Borrego  Mountain  earth- 
quake and  a  1934  earthquake  in  the  Colorado  River  Delta  area 
of  Baja  California.  However,  no  verified  fault  displacements 
have  occurred  on  its  northern  section  although  numerous  earth- 
quakes have  been  associated  with  it.  Some  reports  of  ground 
breakage  on  the  northern  part  of  the  San  Jacinto  fault  during  an 
1899  earthquake  were  published  by  Danes  (1907),  in  an  Austri- 
an geological  publication,  but  these  reported  ruptures  could  have 
been  caused  by  landsliding  (Allen  and  others,  1965,  p.  767; 
Sharp,  1972). 

Recorded  Fault  Creep 

Fault  creep  is  described  as  slow  ground  displacement  usually 
occurring  without  accompanying  earthquakes.  It  was  first  recog- 
nized on  the  Buena  Vista  fault,  in  an  oilfield  near  Taft,  California 
(Koch,  1932).  It  was  later  recognized  on  the  San  Andreas  fault 
at  a  winery  south  of  Hollister,  (Steinbrugge  and  Zacher,  1960), 
and  since  then  has  been  found  on  several  other  faults  in  Califor- 
nia. It  is  apparently  a  relatively  rare  phenomenon  outside  of 
California.  Creep  may  have  preceded  the  1959  Montana  earth- 
quake (Myers  and  Hamilton,  1964).  Outside  the  United  States 
it  has  only  been  reported  in  Turkey.  On  the  Fault  Map  of  Cali- 
fornia, fault  creep  has  been  used  as  the  sole  criterion  for  classify- 
ing the  six  following  faults  as  having  activity  during  historic 
time:  Concord,  Antioch,  Kern  Front,  Casa  Loma,  Buena  Vista, 
and  Mesa  (see  Table  4,  Part  C). 

Fault  creep  of  tectonic  origin  is  often  difficult  to  distinguish 
from  nontectonic  ground  displacement  resulting  from  ground- 
water or  oil  withdrawal.  In  fact,  creep  on  the  Buena  Vista  fault, 
as  well  as  on  the  Kem  Front  fault,  is  today  generally  attributed 
to  withdrawal  of  oil.  Creep  on  the  Casa  Loma  fault  is  considered 
by  some  to  be  a  result  of  ground-water  withdrawal.  The  creep 
shown  on  the  Mesa  fault  is  questionable,  and  there  are  now 
indications  that  earlier  reports  of  creep  may  have  been  in  error. 
The  places  where  fault  creep  has  been  observed  and  recorded  are 
shown  on  the  map  with  red  dots  on  the  fault.  These  locations 
include  both  tectonic  and  nontectonic  creep. 

Fault  creep  has  been  noted  on  some  faults  in  areas  where  the 
ground  has  been  previously  broken  by  historic  earthquakes  (for 
example,  on  segments  of  the  San  Andreas,  Hayward.  Coyote 
Creek,  and  Imperial  faults).  But  fault  creep  has  also  been  ob- 
served on  other  segments  of  active  faults  that  have  had  no  record 
of  earthquake  ground  ruptures  during  historic  time  (for  exam- 
ple, certain  parts  of  the  San  Andreas  and  Calaveras  faults). 

Since  1975,  when  the  Fault  Map  of  California  was  published, 
fault  creep  in  places  on  the  Imperial  fault  has  been  rcpi>rtcd 
(Gilman  and  others,  1977).  A  segment  of  the  Brawley  fault  (not 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


19 


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20 


DIVISION  OF  MINES  AND  GEOLOGY 


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1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  21 


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22 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Table  4,  Part  B.      Historic  surface  faulting  associated  with  earthquakes  in  Nevada  and  Baja  California. 


Earthquake 

Fault 

Reference-" 

Year 

Locotion 

Magnitude 

Name 

Location 
number 
(See 
Fig.  4) 

Length 
surface 
rupture 
(kilometers) 

Maximum 
displacement 
and    type  of 
slippage' 

[miles] 

1869 

Nevada 

7.0 1 

Olinghouse 

36 

No  data 

No  data 

Slemmons.  1967. 

19031? 

) Nevada 

No  data 

Gold  King 
(Also  see  44) 

37 

19  km  (?) 
[12  m,  (?)] 

No  data 

Bonilla.  1970;  Slemmons  and  others. 
1959;  Toctier  and  others.  1957. 

1915 

Nevada 

7.6 

Pleasant  Valley 

38 

32-64  km 
[2040  mi] 

N  4.6m 

Bonilla.  1970  Jones,  1915. 

1932 

Nevada 

7.3 

Cedar  Mountain 

39 

61.2  km 
[38  mi] 

RL  8.5  m 
V  1.2m 

Bonilla.  1970;  Gianella  and  Callaghan. 
1934. 

1934 

Nevada 

6.5 

Excelsior  Mtn. 

40 

1.5  km 
[0.9  mi] 

LL  slight 
N  1.2cm 

Bonilla.  1970;  Callaghan  and  Gianella 
1935, 

1934 

Mexico 

7.1 

San  Jacinto 

41 

Faulting 
inferred  from 
aerial  pfiotos 

RL  (') 

Bonilla.  1970;  Kovach.  1962. 

1954 
(July) 

Nevada 

6.6 

Rainbow  Mtn. 

42 

17.7  km 
[11  mi] 

N  3.1cm 

Bonilla,  1970;  Tocher.  1956, 

1954 
(Aug. 

Nevada 

6.8 

Rainbow  Mtn. 

43 

30.6  km 
[19  mi] 

N  0.76m 

Bonilla,  1970;  Tocher,  1956. 

1954 

Nevada 

7.1 

Fairview 
Gold  King 

44 

58  km 
[36  mi] 
Part  of 
Fairview  F.Z. 

RL  4.3  m 
N  3.7m 
RL  little  or 
none.V  2  feet 

Bonilla.  1970;  Slemmons.  1957. 
Slemmons  and  others.  1959. 

1954 
1956 

Nevada 
Baja.  Mexico 

68 
6.8 

Dixie  Valley 
San  Miguel 

45 
46 

61.2  km 
[38  mi] 
19+  km 
[12+  mi] 

N  2.1+  m 
(4.6m  scarp) 
N  Im 
RL  08  m 

Bonilla,  1970;  Slemmons.  1957. 
Bonilla.  1970;  Shor  and  Roberts,  1958. 

Table  4,  Part  C.       California  faults  displaying  fault  creep  slippage   not  associated  with  earthquakes. 


Fault 

Location 
number 
(see 
Fig.  4) 

Reference^ 

San  Andreas  " 

- 

Nason  and  ottiers.  1974 

Hayward  " 

- 

Nason  and  others.  1974 

Calaveras 

47 

Nason  and  others.  1974. 

Concord 

48 

Sharp.  1973. 

Anliocti  (?) 

49 

Burke  and  Helley.  1973. 

Kern  Front 

50 

Manning.  1968  (p.  132.  139). 

Casa  Loma  (San  Jacinlo  F  Z  ) 

51 

Felt  and  others.  1967  (p  22.  25.  27.  28). 

Buena  Vista 

52 

Koch.  1933.  Manning,  1968  (p.  133-134);  Nason  and  others, 
(p    100-101), 

1968 

Mesa  |7| 

53 

Wilot.  1972;  Pollard,  1973.  pers  comm. 

Coyote  Cn-  ■ 

b.l 

Clark,  1972  (p.  73) 

Imperial 

55 

Gilman  and  others.  1977. 

Brawley" 

56 

Sharp.  1976  (p   1153). 

Busch 

57 

Rogers.  1967 

'/.LicamB** 

57A 

Smith.  1981 

1984 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


23 


Table  4,  Part  D.      Triggered  creep  along  faults 

with  earthquakes  in  California. 

Eorffiquake  Fault 

Triggered  Fault 

Reference^ 

Year 

Location 

Magnitude 

Name 

Location 
number 

Length 
surface 

Maximum 
displacement 

(See 
Fig.  4) 

rupture 

and    type  of 
slippage' 

1940      Imperial                   6  7'° 

Brawley"                      58 

No  data 

V  25.4  cm 

Sharp.  1976  (p    1152), 

1952       White  Wolf(?)        77 

Garlock  (?)                   59 

122  meters 
[400  feet] 

No  data 

Buwalda  and  St  Amand.  1955  (p.  53); 
Clark.  1973, 

1965      No  data                   4.0  (') 

Superstition  Hills         60 
(San  Jacinto  F.Z. ) 

1  km 
[0.6  mi] 

No  data 

Allen  and  others,  1972  (p,  94), 

1968      Coyote  Creek         6  5 

'Superstition  Hills         61 

(San  Jacinto  F.Z, ) 
i  Imperial                         62 

San  Andreas                63 

7,7  km 
[4,8  mi] 
19,3  km 
[12  mi] 
No  data 

RL  less 
than  2,5  cm 
RL  less 
than  2,5  cm 
RL  less 
than  2,5  cm 

Allen  and  others.  1968 
Allen  and  others,  1968 
Allen  and  others.  1968 

1969      No  data                  No  data 

Superstition  Hills         64 
(San  Jacinto  F.Z.) 

No  data 

No  data 

Allen  and  others,  1972  (p.  94). 

1971       Superstition           5.3 
Hills 

Imperial                          65 
(San  Jacinto  F,Z, ) 

27,4  km 
[17  mi] 

RL  1,5  cm 

Allen  and  others.  1972  (p,  89).  Kahle 
(pars,  comm). 

FOOTNOTES  FOR  TABLE  4   (PARTS  A  THROUGH  D) 

Abbreviations:     RL  —  right  lateral,  LL  =  left  lateral,  V  =  vertical,  N  =  normal,  m  =  meters,  cm    =  centimeters. 

Multiple  fault  ruptures  on  the  same  fault,  but  not  necessarily  at  the  same  place. 

See  references  cited  (at  end  of  Pan  II)  for  complete  bibliographic  description. 

Location  of  1852  earthquake  is  questionable  (see  text  p    IS). 

May  represent  two  (possibly  three)  events  (Nason,  R.D.,  1980.  personal  communication). 

The  1875  earthquake,  until  recently,  was  thought  to  have  occurred  in  Mohawk  Valley  as  shown  on  Fault  Map  of  California  (1975).  Some  22  years  after  the  event. 

Turner  ( 1897).  in  talking  with  local  residents,  thought  he  could  IcKate  ground  ruptures  for  this  event  near  Cho.  New  data  and  isoseismal  maps  (Toppozada  and  others, 

1980)  indicate  the  earthquake  probably  was  centered  in  the  Honey  Lake  area,  probably  on  the  Honey  Lake  fault. 

Two  early  newspaper  accounts  recently  uncovered  (Toppozada  and  others,  1980)  describe  a  fissure  0.5  to  1  mile  long  near  Allendale,  5  miles  west  of  Dixon.  [Not  plotted 

on  Fault  Map  of  California  (1975)  ] 

Questionable  fault  rupture — may  have  been  landshdes  (Allen  and  others.  1965;  Sharp.  1972).  Not  plotted  on  Fault  Map  of  California,  nor  on  Figure  4. 

Questionable  fault  rupture — crackmg  may  have  been  caused  by  shaking  only. 

Widely  hsted  as  magmtude  7.1 — recalculated  by  C.I.T.  to  be  6.7  (Hilman  and  others.  1973). 

Displacement  given  includes  tectonic  creep  that  occurred  within  SO  days  following  main  shock. 

Surface  fault  rupture  not  conclusive. 

Some  uncertainty  regarding  earthquake  associated  with  1968  ground  rupture  near  La  Habra  (Yerkes.  1972). 

Brawley  fault  of  R.V  Sharp  (1976)  is  not  shown  on  the  Fault  Map  of  California  (1975  ed.)  because  it  was  reported  after  the  Fault  Map  was  pubUshed.  Sharp's  "Brawley 

fault"  IS  oriented  somewhat  differently  than  the  fault  by  the  same  name  shown  on  the  Fault  Map  of  California  based  on  Elders  and  others.  1 972. 

Numerous  occurrences  of  creep  along  this  fault;  see  Figure  4. 

Not  plotted  on  Fault  Map  of  California  because  first  reported  in  1977 

Evidence  of  some  surface  ruptures  in  1940  at  the  lime  of  the  Impenal  earihquake  according  to  report  in  R.V.  Sharp  <  1976.  p.  1152)  and  suggestions  of  creep  over  an 

extended  period  of  time  (1976.  p.  1153),  Not  plotted  on  Fault  Map  of  California  because  first  reported  in  1976. 


shown  on  the  Fault  Map  of  Cahfornia)  is  also  undergoing  fault 
creep  (Sharp,  1976). 

Fault  creep  is  not  well  understood.  It  may  signify  a  building 
of  stress  along  a  fault  or  it  may  indicate  a  releasing  of  stress. 
Research  into  fault  mechanics  may  eventually  explain  its  causes. 

Another  type  of  creep,  designated  "triggered  creep,"  has  been 
observed  in  recent  years.  This  type  of  creep  occurs  on  a  fault 
after  it  has  been  triggered  by  a  strong  earthquake  on  some  other 
fault.  The  1968  Borrego  Mountain  earthquake,  for  example, 
which  is  centered  on  the  Coyote  Creek  fault,  triggered  movement 
on  the  Superstition  Hills,  Imperial,  and  San  Andreas  faults. 
Other  triggered  creep  has  been  noted  on  the  Imperial  fault  in 
1971  and  on  the  Superstition  Hills  fault  in  1965  and  1969.  Table 
4,  Part  D  lists  all  the  known  triggered  creep  events  along  faults 
associated  with  earthquakes  in  California.  On  the  Fault  Map  of 
California,  red  squares  are  plotted  where  triggered  fault  creep 
has  occurred,  and  the  date  of  the  causative  earthquake  is  indicat- 
ed. 


Displaced  Survey  Lines 

The  third  criterion  recognized  for  designating  faults  with  his- 
toric ground  displacement  is  measured  displacement  across  sur- 
vey lines.  In  compiling  the  Fault  Map  of  California,  this  criterion 
served  mostly  to  corroborate  other  evidence  for  historic  activity 
(earthquake  ground  rupture  or  fault  creep  slippage).  However, 
one  location  in  the  San  Bernardino  Valley,  on  the  San  Jacinto 
fault,  was  shown  to  have  historic  ground  displacement  based 
solely  on  the  repeated  surveys  of  the  Rialto-Colton  triangulation 
network. 

Seismicity 

A  fourth  criterion,  active  seismicity,  was  considered  in  classi- 
fying faults  with  historic  activity.  This  criterion  was  used  on  a 
preliminary  unpublished  compilation  but  not  on  the  final  map. 
An  attempt  was  made  to  classify  a  fault  as  having  historic  activ- 
ity in  cases  where  there  appeared  to  be  a  close  correlation 


24 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


between  the  epicenter  locations  of  earthquakes  and  a  specific 
fault.  Both  macroseismic  and  microseismic  activity  were  consid- 
ered, and  all  types  of  events  were  evaluated — whether  they  were 
repealed  earthquakes  over  a  period  of  years,  aftershocks  of  a 
larger  event,  or  microcarthquakes  detected  by  extensive  continu- 
ous monitoring  by  close  seismic  survey  networks.  The  guiding 
factor  was  w  hether  or  not  an  alignment  of  epicenters  appeared 
to  be  clearly  related  to  a  specific  fault.  This  criterion  was  used 
most  sparingly  because  of  imprecise  location  of  epicenters  (espe- 
cially with  older  data).  In  this  way  several  faults  thai  otherwise 
had  no  observable  historic  surface  fault  displacement  were  tenta- 
tively classified  with  the  group  of  historic  faults.  These  included 
the  Newport-Inglewood,  Palos  Verdes,  Mendocino,  Sargent, 
Mission  Creek.  Palo  Colorado-San  Gregorio  faults,  the  northern 
part  of  the  San  Jacinto  fault,  and  the  southern  part  of  the  Healds- 
burg  fault.  However,  because  of  disagreement  among  seismolo- 
gists about  the  significance  of  micn>earthquake  alignments,  and 
because  of  the  uncertainties  involved  with  ascertaining  align- 
ments among  the  random  distribution  of  macrocarthquakes,  a 
decision  was  made  not  to  include  seismicity  with  the  other  wide- 
ly recognized  geologic  and  historic  criteria  used  in  making  this 
official  fault  map  of  the  state. 

The  uncertainty  of  relating  individual  macrocarthquakes 
(magnitude  3  or  greater)  to  specific  faults  in  cases  where  there 
is  no  ground  displacement  is  well  known  among  seismologists, 
although  sometimes  overlooked  by  geologists.  The  problem  lies 
with  the  accuracy  of  epicenter  locations.  "Without  a  group  of 
several  good  stations,  velocities  and  crustal  structures  are  uncer- 
tain and  location  of  epicenters  is  unreliable"  (Richter,  1958,  p. 
315). Well-recorded  earthquakes  may  be  located  accurately  within 
5  km.  (3  mi.),  but  most  epicenter  maps  include  locations  with 
far  less  accuracy.  Also,  there  are  instances  in  which  well-located 
earthquakes  do  not  line  up  with  known  faults. 

In  recent  years,  the  sensitivity  of  seismograph  networks  has 
been  greatly  increased.  As  a  result,  a  remarkably  close  relation 
between  microseismicity  (magnitudes  less  than  3)  and  specific 
faults  in  certain  parts  of  the  state  has  been  confirmed.  Figure  5 
shows  how  a  section  of  the  San  Andreas  fault,  and  the  Hay  ward, 
Calaveras  and  Rodgers-Creek  faults  are  clearly  outlined  by  the 
alignment  of  very  small  earthquakes.  However,  historically  ac- 
tive faults  may  for  periods  of  time  show  no  microseismic  activity; 
thus,  a  lack  of  microearthquakes  is  not  conclusive  evidence  that 
a  fault  is  dead.  For  example,  north  of  San  Francisco,  where  a 
long  stretch  of  the  San  Andreas  fault  ruptured  in  1906,  no  recog- 
nizable microseismicity  or  macroseismicity  has  occurred  since 
1906. 


Quaternary  Faults 

A  Quaternary  fault  is  any  fault  that  shows  evidence  of  having 
been  active  during  approximately  the  last  two  million  years.  The 
Quaternary  period  therefore  encompasses  those  historic  faults 
just  described  in  the  previous  section.  The  Fault  Map  of  Califor- 
nia, however,  treats  the  two  terms  as  mutually  exclusive  time 
intervals;  that  is,  a  Quaternary  fault  is  any  fault  not  considered 
an  histonc  fault  \\\d\  shows  evidence  of  having  been  active  during 
approximately  the  last  two  million  years.  Quaternary  faults  are 
indicated  by  orange  lines;  historic  faults,  as  we  have  seen,  are 
indicated  by  red  lines. 

Faults  designated  by  heavy  black  linc-s  are  those  without 
rcfo^«;ir«/ Quaternary  displacement;  faults  in  this  category  are 
discussed  later  in  the  section  entitled  "Pre-Quaternary  faults." 


Identification 

Quaternary  faults  are  recognized  by  various  criteria.  Because 
some  of  the  evidence  becomes  destroyed  with  time  and  is  not 
always  clearly  recognizable,  geologists  try  to  utilize  as  many  bits 
of  evidence  as  they  can  accumulate  in  their  interpretation.  Some 
of  the  most  commonly  used  criteria  include  the  following: 

(1)  Scarps  in  alluvium,  terraces,  or  other  Quaternary 
units; 

(2)  Lateral  offsets  in  Quaternary  units; 

(3)  Stream  courses  offset  in  a  systematic  direction; 

(4)  Alignment  of  fault-caused  depressions,  such  as  sag 
ponds,  fault  troughs,  and  fault  saddles; 

(5)  Markedly  linear  and  steep  mountain  fronts  that  ap- 
pear to  be  associated  with  a  bordering  concealed  fault 
trace; 

(6)  Ground-water  barriers  in  Quaternary  sediments 
caused  by  faults  (such  barriers  may  be  evidenced  by 
vegetation  contrasts,  alignment  of  springs  and  seeps, 
or  by  well  data  showing  comparable  water  tables  at 
different  levels). 

Problems 

Using  the  above  criteria,  numerous  faults  can  be  shown  to 
have  Quaternary  activity;  however,  as  with  any  classification, 
there  are  situations  where  it  is  difficult  to  decide  whether  to 
designate  the  fault  movement  as  being  Quaternary  in  age. 

In  northeastern  California,  for  example,  a  large  group  of  faults 
within  Quaternary  volcanic  rocks  have  been  shown  as  orange 
lines  on  the  Fault  Map.  However,  in  the  same  area  and  on  the 
same  trend,  many  other  faults  that  occur  wholly  within  some- 
what older  volcanic  units  have  been  shown  as  black  lines.  These 
faults  may  have  formed  at  the  same  time  as  those  faults  in  the 
Quaternary  units,  but  without  further  evidence  they  cannot  be 
classified  as  Quaternary.  The  faults  in  this  area  were  largely 
determined  by  photo  interpretation  and  only  a  limited  amount 
of  field  checking.  Further  field  work  may  reveal  evidence  of 
Quaternary  displacement  on  many  of  these  faults  in  the  older 
rocks. 

In  various  parts  of  California  extensive  nonmarine  deposits 
were  laid  down  over  a  long  period  of  time  ranging  from  late 
Pliocene  well  into  the  Pleistocene.  These  Plio-Pleistocene  depos- 
its (such  as  the  Paso  Robles  and  Santa  Clara  Formations  in  the 
central  Coast  Ranges)  generally  lack  fossils,  so  the  Pliocene 
portion  of  the  rocks  can  rarely  be  separated  from  the  Pleistocene 
rocks.  Where  these  beds  are  cut  by  faults,  geologists  cannot 
readily  determine  whether  the  faults  were  active  during  Pliocene 
or  Pleistocene  time.  A  decision  therefore  had  to  he  made  by  the 
compiler  as  to  whether  they  should  be  designated  as  Quaternary. 
In  order  to  avoid  overlooking  possible  Quaternary  faults,  it  was 
decided  to  include  these  faults  within  the  Quaternary  category. 

For  dating  the  faults  shown  on  the  Fault  Map  of  California, 
the  Quaternary  rocks  depicted  on  the  new  State  Geologic  Map 
were  used  as  a  guide.  Although  some  of  these  age  designations 
are  probably  incorrect,  they  were  the  most  useful  guide  we  had 
at  the  time.  Even  if  the  rocks  shown  as  Pleistocene  are  somewhat 
older — that  is.  Pliocene — faults  cutting  such  rocks  could  be  post- 
Pliocene,  nonetheless.  In  fact,  if  the  rocks  cut  by  a  fault  are  /art- 
Pliocene  in  age,  then  the  fault  is  most  likely  Quaternary. 

Some  dotted  faults  are  shown  as  being  Quaternary  in  volcanic 
terrain  such  as  at  Mount  Shasta  and  in  Owens  Valley  where 
there  are  alignments  of  Quaternary  volcanic  cones.  These  con- 
cealed "faults"  may  actually  be  fissures  or  fractures  along  which 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


25 


"T 1 1 T 


40*  0.00' 


SACRAMENTO 


SYMBOL 

MAGNITUDE 

. 

M  <    15 

. 

1  5  <   M  <  2  5 

X 

25  <  M  <  35 

X 

35  <   M  <  4  5 

X 

M  >  45 

0 

1      1      I 

50   KM 
1      1      1 

35*0.00 


Figure  5.  Mop  showing  smoll-mognitude  eorthquoke  epicenters  reported  during  1975.  Eorthquokes  in  the  region  enclosed  by  the  dashed  line  ore  generally 
well  recorded  and  located.  Note  the  alignments  developed  olong  parts  of  the  Son  Andreas,  Hayward,  Coloveros  ond  Rodgers  Creek  faults.  (From  McHugh 
and  Lester,  U.S.  Geological  Survey,  Open  File  Report  78-105 1. 1 


26 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


lava  was  extruded,  and  may  in  themselves  have  little  or  no 
displacement.  But  because  these  volcanic  rocks  are  Quaternary 
in  age  and  occur  in  an  area  where  known  Quaternary  fault 
structures  exist,  these  structures  are  interpreted  to  be  of  early 
Quaternary  age  also. 

Faults  that  were  determined  solely  on  the  basis  of  geophysical 
interpretations  have  been  used,  but  with  caution.  The  same  is 
true  of  Quaternary  faults  located  on  the  basis  of  well-log  data. 
The  quality  of  the  logs  and  the  well  spacing  were  critical  factors 
that  were  considered.  With  geophysical  interpretations  (espe- 
cially those  made  by  geologists),  the  date  of  the  survey  and  the 
experience  of  the  interpreters  were  considered,  and  consultation 
with  Rcxlger  Chapman,  the  Division's  geophysicist,  was  sought 
before  deciding  w  hethcr  to  use  certain  fault  interpretations  based 
on  geophysical  data. 

In  cases  where  a  geologic  map  indicates  a  fault  separating 
bedr(xk  from  alluvium,  especially  along  a  mountain  front,  it  is 
often  difTicult  to  determine  what  age  the  geologist  considered  the 
fault  to  be.  Sometimes  the  map's  scale  is  such  thai  it  cannot  show 
a  fault  or  fault  zone  in  bedrock  close  to  the  alluvium  contact. 
Sometimes,  when  a  mapper  interprets  a  mountain  front  as  an 
eroded  fault-line  scarp,  the  geologist  may  not  be  particularly 
concerned  about  the  age  of  the  fault  he  is  depicting  and  simply 
neglect  to  show  it  as  a  dotted  line  in  the  alluvium  paralleling  the 
mountain  front.  If  such  a  fault  is  not  discussed  in  the  text,  it  is 
impossible  to  know  whether  it  was  considered  to  be  a  young  or 
an  old  feature.  This  problem  most  commonly  occurs  in  the  Basin 
and  Range  and  Mojave  Desert  provinces.  In  compiling  the  Fault 
Map  of  California,  if  a  bedrock-alluvium  fault  relationship  was 
not  clear  from  the  source  data,  the  fault  was  usually  shown  in 
black — not  to  indicate  that  the  fault  movement  was  necessarily 
pre-Quaternary,  but  that  the  age  of  movement  was  undeter- 
mined. 

In  many  cases,  it  is  difficult  to  recognize  Quaternary  displace- 
ment along  a  fault  when  the  fault  lies  wholly  within  rocks  older 
than  Quaternary.  This  is  especially  true  in  areas  of  great  rainfall 
where  subtle  geomorphic  evidence  is  easily  destroyed  or  covered 
by  vegetation.  Also,  some  faults  have  been  designated  by  geolo- 
gists as  Quaternary  solely  on  the  basis  of  photo-interpretation  of 
suspected  geomorphic  features.  Later  field  investigation,  includ- 
ing trenching,  may  disprove  the  Quaternary  designation  or,  in 
some  cases,  the  existence  of  a  fault. 

Some  faults  that  may  actually  have  been  active  in  historic  time 
are  shown  as  Quaternary  because  the  activity  went  unobserved 
or  unrecorded.  It  is  not  surprising  that  such  activity  on  faults 
located  in  sparsely  populated,  remote  areas  such  as  in  the  deserts 
or  in  the  heavily  forested  mountains  would  go  unnoticed  or,  if 
noticed,  never  be  recorded. 

Plio-Pleistocene  Boundary  Controversy 

The  duration  of  the  Quaternary  period  is  not  well  defined,  and 
the  position  of  the  Pliocene-Pleistocene  time  boundary  in  Cali- 
fornia has  been  considered  at  different  places  by  various  experts 
in  recent  years.  The  Pliocene-Pleistocene  boundary  is  generally 
based  on  palcontological  concepts  and  the  first  evolutionary  ap- 
pearance of  certain  species  (Handy  and  Wilcoxon,  1970,  p. 
2939).  The  palcontological  evidence  is  correlated  to  magnetic 
events,  paleo-climatic  cycles,  glacial  events,  and  radiometric  age 
determinations.  Because  of  worldwide  problems  in  correlation 
and  disagreements  among  the  experts,  the  duration  of  the  Qua- 
ternary period  has  been  variously  reported  as  being  from  one 
million  to  three  million  years.  The  longer  lime  interval  has  now 
been  largely  discredited  (Bandy,  1969,  also  Handy  and  Wilcox- 
on, 1970,  p.  2939),  and  an  age  closer  to  two  million  years  is  more 


widely  accepted.  However,  because  three  million  years  was  the 
accepted  age  for  the  Quaternary  period  while  some  of  the  State 
Atlas  sheets  were  being  compiled,  certain  volcanic  rocks  of  that 
age  (determined  radiometrically)  were  classified  as  Quaternary. 
Some  faults  within  these  volcanic  rocks  could  thus  be  older  than 
the  age  implied  on  the  Fault  Map  of  California. 

Major  Quaternary  Faults 

Quaternary  faults  are  abundant  and  widespread  in  California. 
Many  are  short  minor  breaks,  but  others  consist  of  numerous 
small  segments  that  define  major  structural  trends.  Some  Qua- 
ternary faults  are  extensive,  but  are  largely  concealed  under 
alluvium.  In  order  to  emphasize  the  major  Quaternary  faults  or 
fault  zones,  a  pale  orange  band  has  been  superimposed  on  the 
map  portrayal  of  the  fault.  Certain  criteria  were  used  to  decide 
which  Quaternary  faults  should  be  selected  for  such  emphasis. 
To  be  considered  "major,"  a  Quaternary  fault  had  to  be  charac- 
terized by  one  or  more  of  these  factors: 

(1)  The  fault  is  of  considerable  length  (for  example,  usu- 
ally more  than  30  miles  [48  km]). 

(2)  The  fault  is  associated  with  an  alignment  of  numerous 
earthquake  epicenters  (such  as  with  the  Sargent  and 
Newport-Inglewood  faults). 

(3)  The  fault  trace  is  continuous  with  segments  that  have 
historic  displacement  (for  example,  the  Green  Valley 
fault), 

(4)  The  fault  is  associated  with  youthful  major  mountain 
scarps  or  mountain  ranges  (for  example.  Surprise  Val- 
ley, Honey  Lake,  and  Panamint  Valley  faults). 

(5)  The  fault  is  associated  with  strong  geophysical  anomal- 
ies (for  example,  the  Likely,  Surprise  Valley,  San  Cle- 
mente,  and  Mendocino  faults). 

Certain  faults  near  the  California-Nevada  border  that  are 
shown  as  major  Quaternary  faults  appear  to  be  short.  These 
faults,  however,  continue  for  many  miles  into  Nevada  and  are, 
therefore,  major  structural  features. 

As  with  any  classification,  cases  arose  where  the  data  were  not 
clear-cut,  and  it  was  necessary  to  decide  somewhat  arbitrarily 
whether  to  include  a  fault  as  major.  In  general,  the  policy  was 
to  keep  the  number  of  emphasized  faults  to  a  minimum.  If  one 
were  to  extrapolate  segments  of  faults  across  greater  distances, 
many  more  Quaternary  faults  could  be  shown  as  major,  but  the 
writer  preferred  to  await  additional  information  in  such  cases. 


Philisophy  of  Conservatism 

In  general,  a  "philosophy  of  conservatism"  was  followed  in 
depicting  the  c.v/cvj/ of  Quaternary  faulting;  that  is,  where  local 
evidence  indicated  that  a  fault  has  had  displacement  during 
Quaternary  time,  the  entire  length  of  the  fault  was  shown  as 
Quaternary  unless  contrary  evidence  indicated  otherwise.  This 
"philosophy,"  which  has  also  been  expressed  by  the  VS.  Geo- 
logical Survey  (Wentworth,  Ziony,  and  Buchanan,  1970,  p.  4-5), 
takes  into  account  the  desirability  of  calling  possible  geologic 
problems  to  the  attention  of  decision-makers  fK'fore  critical 
structures  are  built.  If  possible  problems  are  known,  they  can  be 
investigated,  and  their  presence  or  absence  be  established,  so  that 
appropriate  modifications  of  plans  can  be  made  in  advance  of 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


27 


siting  or  before  detailed  design  and  construction.  Omission  of  the 
possible  geologic  hazards  might  lead  users  of  the  map  to  an 
erroneous  conclusion  that  none  existed.  The  maps  that  were 
compiled  by  Wentworth,  Ziony,  and  Buchanan  of  several  coastal 
areas  in  southern  California  were  used  in  the  preparation  of  the 
Fault  Map  of  California,  and  in  these  areas  their  philosophy  was 
directly  incorporated.  Elsewhere  in  the  state,  this  conservative 
philosophy  was  followed,  but  perhaps  not  as  rigorously  because 
of  the  vastly  greater  area  covered  and  the  less  specific  character 
of  the  information  available.  The  U.S.  Geological  Survey  prac- 
tice is  to  include  some  questionable  information  as  long  as  it  has 
some  basis  and  is  reasonable  (Wentworth  and  others,  1970; 
Ziony  and  others,  1974).  Hence,  individual  faults  and  connec- 
tions between  faults  were  shown  where  they  were  considered 
reasonable,  even  though  conclusive  evidence  for  their  existence 
may  be  lacking. 

On  the  Fault  Map  of  California,  aligned  faults  were  generally 
not  connected  unless  the  gap  between  was  too  narrow  to  repre- 
sent adequately  at  the  map's  scale;  instead,  an  attempt  was  made 
to  follow  the  source  data  as  closely  as  possible.  However,  because 
of  an  extensive  review  of  the  Fault  Map  by  many  geologists,  both 
the  location  and  the  extent  of  Quaternary  faults  shown  on  the 
Fault  Map  were  carefully  considered  and  many  modifications 
were  made.  As  a  result,  the  1975  Fault  Map  of  California  is  the 
most  complete  and  accurate  portrayal  of  faults  known  in  the 
state  at  the  time  of  publication.  The  data  on  faults  of  California 
are  constantly  being  evaluated  and  re-evaluated  and,  as  time 
passes,  new  information  will  support  or  modify  the  Fault  Map. 
It  is  obvious,  therefore,  that  the  map  should  be  periodically 
revised  and  new  editions  pubUshed. 

Pre-Quaternary  Faults 

Pre-Quatemary  faults  are  shown  by  heavy  black  lines  on  the 
Fault  Map  of  California.  They  are  defined  as  faults  that  are  older 
than  Quaternary  (older  than  two  milhon  years)  or  faults  with- 
out recognized  Quaternary  displacement.  There  may  be  in- 
stances in  which  the  youthfubiess  of  a  fault  is  not  recognized  for 
several  reasons: 

(1)  The  fault  may  not  affect  Quaternary  rocks  because 
none  were  present  or,  if  ever  present,  they  have  since 
been  removed  by  erosion. 

(2)  The  fault  may  not  retain  evidence  of  youthful  displace- 
ment because  such  evidence  has  been  destroyed  by 
erosion  or  covered  by  vegetation.  This  is  especially  true 
in  areas  of  high  rainfall. 

(3)  The  stratigraphic  or  geomorphic  evidence  may  have 
been  removed  or  covered  by  works  of  man,  such  as  in 
urban  areas. 

(4)  The  fault  may  not  have  been  studied  in  sufficient  detail 
to  ascertain  when  displacement  last  took  place. 

Therefore,  many  of  the  faults  shown  as  heavy  black  lines  may 
be  young  and  possibly  may  become  active.  An  example  of  this 
is  the  Cleveland  Hill  fault,  which  ruptured  in  the  August  1975 
Oroville  earthquake.  Subsequent  studies  have  shown  that  the 
fault  lies  within  the  Foothill  fault  system,  which  extends  for  more 
than  240  km  (150  miles),  but  prior  to  the  1975  earthquake,  most 
geologists  viewed  this  system  as  a  very  ancient  and  "seismically 
dead"  fault  zone.  Also,  it  must  be  stressed  again  that  many  faults 
have  been  included  with  the  faults  designated  as  pre-Quatemary 
because  of  a  lack  of  age  data. 


Accuracy  of  Fault  Locations 

Fault  traces  are  indicated  in  the  same  way  on  the  Fault  Map 
of  California  and  the  Geologic  Map  of  California.  The  faults  are 
indicated  by  solid  lines  where  the  location  of  its  trace  is  accurate, 
by  dashed  lines  where  they  are  approximately  located  or  in- 
ferred, and  by  dotted  lines  where  covered  by  younger  rocks  or 
concealed  by  lakes  or  bays.  The  fault  traces  are  queried  where 
their  continuation  or  existence  is  uncertain. 

The  accuracy  of  fault  locations  depends  on  the  area  studied 
and  on  the  confidence  that  the  geologists  have  in  their  work.  A 
geologist  may  show  a  fault  as  solid  or  dashed  depending  on  such 
factors  as  how  well  the  feature  is  exposed,  the  scale  of  the  map, 
the  amount  of  time  spent  in  the  field,  the  extent  of  vegetative 
cover,  and  the  complexity  of  the  geology.  With  such  variables, 
the  degree  of  certainty  in  fault  depiction  varies  greatly  on  a  map 
compilation  such  as  the  Fault  Map  of  California.  However,  even 
though  the  degree  of  certainty  may  not  be  uniform,  the  map 
accurately  reflects  the  source  data  (within  the  limits  of  scale) 
and  gives  the  map-user  an  indication  of  the  degree  of  certainty 
on  the  location  shown  for  the  various  faults  within  the  state. 
Thus,  the  map-user  should  be  able  to  distinguish  those  faults  that 
are  well  located  (shown  by  a  solid  hne)  from  those  that  have 
some  degree  of  uncertainty  in  location  or  existence  (shown  by 
dashed  or  queried  lines) .  Of  course,  to  be  more  precise,  a  map- 
user  should  refer  to  the  larger  scale  maps  from  which  the  compi- 
lation was  prepared  (Appendix  D). 

The  map-user  must  keep  in  mind  three  factors  regarding  the 
accuracy  of  faults  portrayed  on  the  Fault  Map.  First,  a  fault  is 
not  usually  a  simple,  continuous  feature;  more  often  than  not  it 
is  a  zone  or  feature  made  up  of  discontinuous  segments.  Second- 
ly, geologic  features  are  mapped  in  the  field  by  "eye"  as  they 
relate  to  topographic  and  cultural  features.  Where  a  fault  crosses 
a  featureless  or  gently  undulating  region,  or  where  the  land  is 
densely  vegetated,  the  mapped  fault  traces  may  be  off  by  signifi- 
cant distances.  Thirdly,  on  the  1:750,000  scale  map,  the  width 
of  a  scribed  fault  line  (0.012  of  an  inch)  represents  in  itself  about 
232  meters  (760  feet). 

Depiction  of  concealed  faults  poses  a  special  problem,  particu- 
larly for  the  faults  in  the  Great  Valley.  Here  the  fault  evidence 
is  taken  largely  from  oil  company  maps  of  selected  subsurface 
horizons,  and  many  of  the  faults  shown  are  at  great  depth.  If  a 
fault  is  vertical,  its  projected  surface  location  lies  directly  over 
the  fault  at  depth.  However,  if  the  fault  is  inchned,  as  commonly 
happens,  the  vertical  projection  of  the  fault  to  the  surface  is  not 
directly  over  the  fault.  Such  projections  shown  on  the  Fault  Map 
can  only  be  approximate  and  may  indicate  fault  trends  only.  The 
main  purpose  of  showing  the  faults  is  to  indicate  that  the  Great 
Valley  is  not  an  area  devoid  of  faults.  More  subsurface  informa- 
tion would  undoubtedly  show  that  the  Great  Valley  harbors 
many  more  faults  than  the  Fault  Map  of  Cahfomia  now  indi- 
cates. 

Faults  such  as  the  San  Andreas,  Hayward,  San  Jacinto,  White 
Wolf,  and  San  Fernando,  which  have  ruptured  during  historic 
time,  and  the  Garlock  fault,  so  well  exposed  in  the  semi-arid 
desert  of  southern  California,  have  all  been  mapped  in  great 
detail.  These  studies  show  that  the  faults  occur  as  a  series  of 
multiple  breaks,  rather  than  as  a  single  continuous  fracture. 
Large-scale  strip  maps  of  these  faults  were  used  in  our  compila- 
tion as  the  source  data  for  showing  more  meaningfully  the  actual 
nature  of  these  important  California  faults. 

Offshore  faults  that  are  concealed  beneath  the  ocean  (they  are 
discussed  in  the  next  section)  are  shown  as  dashed  lines  on  the 
compiled  map  to  indicate  that  their  location  is  generally  less 
accurate  than  is  the  location  of  faults  mapped  on  land.  Such 


28 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


faults  are  located  by  acoustic-reflection  profiling  from  ship- 
board, and  the  problems  of  ship  position  and  record  interpreta- 
tion naturally  introduce  certain  inaccuracies. 

Offshore  Structure 

A.C.  Lawson  (1893)  was  one  of  the  first  to  point  out  dias- 
trophism  along  the  coast  of  southern  California  based  on  an 
analysis  of  the  topography  of  the  Channel  Islands.  He  noted  that 
the  prominent  marine  terraces  at  San  Pedro  Hill  on  the  mainland 
and  on  San  Clemente  Island  do  not  exist  on  Santa  Catalina 
Island.  He  attributed  this  to  submergence  of  Santa  Catalina 
Island.  Later  he  made  structural  interpretations  of  the  California 
coastal  area  from  bathymetric  charts.  He  concluded  that  "por- 
tions of  the  (continental)  slope  where  the  contours  are  crowded 
together... can  scarcely  be  interpreted  as  other  than  fault  scarps," 
and  he  compared  them  with  the  fault-scarp  of  the  eastern  front 
of  the  Sierra  Nevada  (Lawson  and  others,  1908,  p.  13-15). 

One  of  the  most  detailed  fault  maps  of  the  southern  California 
offshore,  based  chiefly  on  sea  floor  topography,  was  made  by 
K.O.  Emery  (I960,  p.  79).  However,  with  modern  sparker  pro- 
filing, knowledge  of  offshore  structure  has  increased  so  rapidly 
that  faults  and  also  folds  can  be  based  on  much  more  than 
inferences  made  from  the  configuration  of  bathymetry.  Unfortu- 
nately, much  of  this  new  information  is  retained  in  oil  company 
exploration  files  and  is  thus  unavailable,  but  the  broader  aspects 
of  these  data  are  occasionally  released,  as  for  example  in  the 
paper  on  northern  and  central  California  offshore  petroleum 
geology  published  by  the  American  Association  of  Petroleum 
Geologists (Hoskins  and  Griffiths,  1971).  Most  of  the  available 
information,  however,  comes  from  recent  studies  and  pubHca- 
tions  by  the  U.S.  Geological  Survey  and  various  universities  and 
institutions,  especially  the  University  of  Southern  California  and 
the  Scripps  Institute  of  Oceanography. 

Although  the  quality  and  quantity  of  data  are  not  uniform  in 
the  offshore  area,  an  attempt  was  made  to  acquire  all  data  that 
were  available  and  to  show  at  least  some  structural  data  for  the 
entire  California  coastal  area.  Thus,  for  the  first  time,  the  Fault 
Map  of  California  depicts  offshore  faults  (and  on  the  Geologic 
Map  of  California,  offshore  folds  as  well). 

Most  of  the  offshore  structures  record  late  Cenozoic  tectonism 
which  may  in  fact,  be  of  Quaternary  age.  As  incomplete  as  these 
data  are,  one  is  struck  by  the  activity  and  mobility  of  the  conti- 
nental shelf  area.  By  the  depiction  of  offshore  structure,  one  can 
see  the  continuity  of  such  major  faults  as  the  San  Andreas  fault, 
the  Seal  Cove-San  Gregorio-Palo  Colorado-Hosgri  fault  zone, 
and  the  Newport-Inglewood-Rose  Canyon  fault  zone  as  they 
leave  land  and  reenter  at  more  distant  points.  One  can  also 
recognize  the  characteristic  northwest-trending  structural  im- 
print of  the  Coast  Ranges  and  the  Peninsular  Ranges  provinces 
on  the  adjacent  continental  shelf  area  and  the  west-trending 
structural  continuation  of  the  Transverse  Ranges  province  off- 
shore. Also,  a  part  of  the  anomalous  west-trending  Mendocino 
fault  zone  can  be  seen  offshore.  This  feature  actually  extends 
westward  for  more  than  3700  km  (2300  miles)  and  one  can 
ponder  the  character  of  this  structure  as  it  impinges  on  the 
continent  at  Cape  Mendocino.  Menard  (1955)  pointed  out  that 
this  IS  the  only  one  of  the  several  offshore  fracture  zones  that 
offseus  the  continental  slope,  but  the  fault  has  no  clear  topo- 
graphic or  fault  continuation  where  it  comes  ashore  at  Cape 
Mendocino. 

Recognizing  these  offshore  structural  features  is  very  impor- 
tant because  of  their  role  in  the  siting  of  critical  engineering 
facilities  along  the  coast,  and  in  the  evaluation  of  offshore  min- 
eral resources. 


Coast  Range  Thrust 

The  Coast  Range  thrust,  first  described  by  Bailey,  Blake,  and 
Jones  (1970),  is  depicted  by  open  barbs.  This  fault  rnarks  the 
upper  boundary  of  a  long-active,  late  Mesozoic  subduction  zone 
extending  from  Oregon  nearly  to  Santa  Barbara.  In  most  cases, 
the  fault  surface  is  now  very  steep,  but  locally  it  is  flat  or  has  been 
folded  into  prominent  hooks  (Blake  and  Jones,  1977,  p.  6).  It 
is  best  exfKJsed  in  northern  California  and  becomes  more  difficult 
to  follow  in  its  central  and  southern  part  because  of  modification 
by  later  vertical  and  strike-slip  faults  or  because  it  is  concealed 
by  younger  rocks. 

E.H.  Bailey  and  other  geologists  of  the  U.S.  Geological  Survey 
at  Menio  Park  were  most  helpful  in  identifying  this  structure  on 
the  1 :250,000  scale  work  sheets  so  that  it  could  be  more  accurate- 
ly portrayed  on  the  I  ■.750,000  scale  maps  of  the  state. 

The  Coast  Range  thrust  brings  together  the  Mesozoic  rocks 
of  the  Franciscan  Complex  and  the  Mesozoic  rocks  of  the  Great 
Valley  sequence.  The  contact  is  easy  to  recognize  where  the 
ophiolitic  rocks  (a  sequence  of  ultramafic  rocks  with  mafic  rocks 
above)  that  occur  at  the  base  of  the  Great  Valley  sequence  are 
in  contact  with  the  Franciscan  Complex.  However,  if  the  Fran- 
ciscan rocks  are  in  fault  contact  with  strat^i  of  the  Great  Valley 
sequence,  one  cannot  be  sure  whether  the  contact  is  the  Coast 
Range  thrust  or  a  later  vertical  or  strike-slip  fault.  Also,  if  the 
Franciscan  rocks  border  serpentinite,  which  is  itself  not  overlain 
by  other  ophiolitic  rocks  or  strata  of  the  Great  Valley  sequence, 
one  cannot  be  sure  whether  the  contact  is  the  Coast  Range 
thrust.  Such  stratigraphic  problems  made  the  plotting  of  the 
Coast  Range  thrust  very  difficult  in  many  places.  Additionally, 
the  scale  of  the  map  is  such  that  details  of  the  pertinent  stratigra- 
phy do  not  always  show. 

These  newer  concepts  were  not  used  in  the  older  mapping.  In 
fact,  faults  on  old  maps  were  sometimes  shown  or  omitted  on  the 
basis  of  now-outmoded  interpretations.  For  example,  ultramafic 
rocks  that  would  be  interpreted  today  as  klippen  of  Great  Valley 
ophiolite  were  mapped  with  intrusive,  non-faulted  contacts. 

The  Coast  Range  thrust  interpretation  gives  us  an  explanation 
of  the  heretofore  inexplicable  juxtaposition  of  the  two  great  belts 
of  coeval  Mesozoic  strata:  the  largely  chaotic  and  rarely  fossilif- 
erous  Franciscan  Complex;  and  the  orderly  and  abundantly  fos- 
siliferous  Great  Valley  sequence.  The  serpentinite  lying 
immediately  above  the  Coast  Range  thrust,  previously  thought 
to  have  been  intruded  into  a  fault  zone,  is  now  interpreted  as  part 
of  the  Mesozoic  oceanic  crust  on  which  the  Great  Valley  se- 
quence was  deposited.  More  recent  work  in  the  Coast  Ranges  has 
expanded  the  concept  of  subducting  plates  into  a  more  complex 
pattern  [for  example,  see  Blake  and  Jones  (1974)  on  the  origin 
of  Franciscan  melanges  as  imbricate  thrust  sheets],  but  this  work 
was  done  after  the  compilation  of  the  1:750,000  scale  geologic 
and  fault  maps  of  California  and  hence  could  not  be  utihzed  on 
these  maps. 


Circular  Fault  Structures 

Two  very  interesting  circular  and  elhptical  fault  structures  lie 
on  the  east  side  of  the  Sierra  Nevada,  just  south  of  Mono  Lake 
(Figure  6).  The  larger  of  the  two  is  the  Long  Valley  Caldera,  a 
16-  by  31-km  ( 10-  by  19-mile)  elliptical  depression.  This  feature 
has  been  mapped  in  part  by  surface  exposures,  but  the  connec- 
tions and  complete  closure  have  been  determined  from  geophysi- 
cal studies,  especially  gravity  surveys  (Pakiser  and  others, 
1964).  The  caldera  has  been  studied  by  several  geologists  over 
the  years,  and  has  recently  received  many  detailed  geological. 


1985 


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29 


II9°I5' 


20  KM 


i,  -   37°45' 


-   37° 30 


MODIFIED  FROM  BAILEY,  AND  OTnERS,  i976  ii8°45'  il8°30' 

Figure  6.      Generalized  map  of  the  Long  Valley-Mono  Craters  area  showing  location  of  faults. 


,8°I5' 


geophysical,  and  geochemical  investigations  as  a  result  of  a  geo- 
thennal  study  program.  According  to  Bailey  and  others  (1976), 
the  Long  Valley  structure  is  a  volcanic  caldera  left  by  the  erup- 
tion of  the  Bishop  Tuff  some  0.7  million  years  ago.  As  a  result, 
the  Long  Valley  magma  was  partially  emptied,  and  its  roof 
collapsed  along  arcuate  ring  faults. 

The  Mono  Craters,  to  the  north,  between  Long  Valley  and 
Mono  Lake,  are  another  ring-fracture  zone  of  nearly  circular 
configuration.  It  is  even  younger  (Holocene)  than  the  Long 
Valley  caldera.  However,  according  to  Kistler  ( 1966),  the  arcu- 
ate fault  trace  of  the  Mono  Craters  is  probably  the  protoclastic 
border  of  a  quartz  monzonite  pluton. 


Future  Changes  in  Fault  Depiction 

Most  of  the  geologic  maps  that  were  used  in  compiling  the 
Fault  and  Geologic  Maps  of  California  probably  show  only  a 
small  fraction  of  the  faults  that  actually  exist  in  the  area  of  the 
maps.  This  is  illustrated  dramatically  in  mine  mapping  where 
many  more  faults  are  commonly  visible  in  underground  work- 
mgs  than  are  apparent  at  the  surface.  On  older  maps,  faults  of 
small  displacement  have  often  been  ignored  and  dismissed  as 
merely  local  features  of  little  significance  in  the  tectonics  of  the 
area.  While  it  may  be  true  that  such  features  have  had  little  effect 
on  past  geologic  history,  such  faults,  especially  in  young  rocks. 


30 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


might  be  harbingers  of  a  developing  stress  system  and  could 
provide  important  clues  to  future  tectonic  activity.  In  recent 
years,  much  more  attention  is  being  paid  to  subtle  geomorphic 
features  that  may  be  evidence  of  Quaternary  faulting.  Thus, 
inconspicuous  geomorphic  features  in  the  topography  of  valley 
alluvium,  like  those  along  the  pre-earthquake  San  Fernando 
fault,  will  hopefully  be  detected  and  allowed  for  in  planning 
decisions. 

Active  faults  and  earthquakes  are  now  the  subject  of  intensive 
research  which  will  improve  the  interpretations  shown  on  the 
Fault  Map  of  California.  Since  its  publication  in  1975,  many  new 
data  have  been  collected,  and  future  detailed  fault  studies  will 
require  many  changes  on  the  Fault  Map.  Thus,  the  length  or 
location  of  certain  faults  will  be  modified,  and  the  class  of  activ- 
ity for  some  faults  will  be  changed.  Some  faults  that  are  now 
shown  as  pre-Quatemary  (or  age  unknown)  will  be  changed  to 
Quaternary  as  evidence  for  Quaternary  movement  is  discovered. 
It  is  less  likely  that  faults  now  shown  as  having  affected  Quater- 
nary rocks  will  be  changed  by  further  studies  unless  the  age  of 
the  rocks  was  originally  misinterpreted.  It  is  also  expected  that 
additional  mapping  will  reveal  new,  as  yet  unsuspected  faults  of 
both  Quaternary  and  pre-Quatemary  ages.  Mapping  tools  being 
used  widely  today  that  only  a  few  years  ago  were  seldom  utilized 
in  fault  evaluation — for  example,  trenching,  boreholes,  detailed 
geomorphological  studies,  and  radiometric  age  determinations 
— are  continually  providing  new  data. 

Hopefully,  future  work  will  be  able  to  determine  the  age  of 
faults  more  accurately  within  the  Quaternary  period,  so  that 
those  faults  that  have  affected  rocks  of  the  late  Quaternary  or 
Holocene  epoch  can  be  shown  separately.  A  better  knowledge  of 
where  faulting  has  occurred  within  the  most  recent  geologic  past 
should  be  helpful  in  inferring  what  is  likely  to  happen  in  the 
future.  Thus,  succeeding  editions  of  the  Fault  Map  of  California 
should  attempt  to  distinguish  those  faults  with  recognized  Holo- 
cene movement,  as  well  as  Quaternary  and  historic  designations. 

The  Fault  Map  of  California,  1975  edition,  is  a  provisional 
inventory  of  faults  in  the  state,  which  should  be  revised  periodi- 
cally to  keep  abreast  of  the  vast  amount  of  new  data  being 
generated.  Such  information  is  vital  to  geologists,  seismologists, 
engineers,  planners,  and  others  who  use  these  data  in  their  work. 


FAULT  PATTERNS 

The  Fault  Map  of  California  depicts  many  fault  types  and 
many  major  and  minor  faults.  On  close  analysis,  a  characteristic 
orientation  of  fault  traces  over  large  segments  of  the  state  is 
apparent.  Some  faults  stand  out  because  of  their  great  length,  or 
because  they  separate  vastly  different  rock  types  (as  is  apparent 
on  the  companion  Geologic  Map  of  California),  or  bound  or 
terminate  major  mountain  ranges.  The  San  Andreas  fault  is 
considered  the  master  fault  in  California,  and  is  now  recognized 
as  one  of  the  major  faults  in  the  world,  separating  two  of  the 
earth's  major  plates.  Conjugate  to  the  San  Andreas  are  the  Gar- 
lock  fault  and  its  probable  offset  western  counterpart,  the  Big 
Pine  fault.  The  Big  Pine  fault,  together  with  the  prominent  Santa 
Ynez  fault  and  the  Malibu-Santa  Monica-Raymond  Hill  faults, 
form  part  of  the  boundaries  of  the  east-trending  Transverse 
Ranges  province  in  southern  California.  The  Sierra  Nevada-Ow- 
ens Valley  fault  zone  defines  a  north-trending  zone  and,  unlike 
the  earlier  described  strike-slip  faults,  is  the  most  conspicuous 
normal  fault  zone  in  the  state  and  perhaps  in  the  western  Cordill- 
era 


Further  consideration  of  the  Fault  Map  of  California  suggests 
certain  unfaulted  areas,  such  as  the  Great  Valley  and  Sierra 
Nevada  provinces.  This  is  partly  misleading.  Intensive  explora- 
tion in  the  oil  and  gas  fields  of  the  Great  Valley  has  revealed  that 
numerous  faults  lie  within  the  sedimentary  strata  of  the  valley 
at  various  horizons,  indicating  faulting  at  different  times  in  the 
past.  It  is  also  suspected  that  extensive  faults  exist  in  the  base- 
ment rocks  underlying  the  Great  Valley. The  Sierra  Nevada,  prin- 
cipally a  huge  batholith  consisting  largely  of  ancient  multiple 
intrusions,  however,  is  apparently  devoid  of  large  faults  except 
in  two  places.  The  first  place  is  near  its  southern  margin,  where 
the  Kern  Canyon  fault  lies  exposed  in  granitic  rocks  and  is 
prominently  emphasized  in  places  by  Pleistocene  glaciation.  The 
second  place  is  at  the  western  margin  of  the  batholith  where  the 
Foothills  fault  system  lies  in  old,  pre-batholith  rocks.  The  well- 
developed  faults  in  the  pre-batholith  rocks  suggest  that  the  site 
of  the  batholith  was  earlier  extensively  faulted,  perhaps  forming 
a  weak  area  in  the  earth's  crust  that  the  magma  could  easily 
invade  during  Mesozoic  time. 


Structural  Provinces 

An  analysis  of  the  structural  features  of  the  state  reveals  cer- 
tain trends  and  patterns  which  appear  to  define  structuraJ  prov- 
inces* and  specific  blocks.  Each  structural  province  is 
characterized  by  faults  of  a  predominant  trend  or  pattern,  or  in 
some  cases,  by  two  or  more  intersecting  trends.  Folds  within 
these  structural  provinces  are  similarly  related,  and  together, 
faults  and  folds  are  the  result  of  stresses  acting  on  and  within 
each  block  in  each  province.  As  will  be  shown,  an  understanding 
of  the  distribution  and  nature  of  Quaternary  faults  in  California 
should  be  a  clue  in  the  understanding  of  present  stress  fields. 

No  attempt  will  be  made  in  this  paper  to  analyze  these  stress 
fields.  Such  analysis  requires  an  understanding  of  the  structural 
blocks  which  respond  as  units  to  any  applied  stresses  and  the 
effort  here  is  to  recognize  and  describe  the  component  blocks. 

Each  of  the  crustal  blocks  is  of  irregular  shape  and  interacts 
with  neighboring  blocks  in  a  complex  fashion,  much  more  com- 
plicated than  the  model  envisioned  for  the  conventional  stress 
ellipsoid  type  of  analysis.  Furthermore,  the  blocks  are  highly 
fractured  internally  and  thus  are  not  homogeneous.  Nonetheless, 
an  understanding  of  the  stresses  on  each  individual  block  would 
be  helpful  in  predicting  where  and  to  what  extent  future  fault 
ruptures  and  earthquakes  might  take  place.  An  understanding  of 
the  distribution  and  nature  of  Quaternary  faults  in  California  is 
one  clue  in  the  understanding  of  present  day  stress  fields. 

As  a  result  of  some  140  years  of  geologic  mapping  in  Califor- 
nia, we  now  have  much  empirical  data  about  the  geologic  effects 
of  the  stress  in  most  parts  of  the  state  as  recorded  in  the  rocks 
in  the  form  of  faults  and  folds.  Because  California  has  had  a  long 
and  changing  structural  history  since  Precambrian  time,  and 
because  so  many  of  the  structures  revealed  in  the  rocks  are  a 
reflection  of  long-sin;e  departed  or  reoriented  stress  fields,  focus 
is  here  made  on  the  most  recent  sequence  of  events  and  on  the 
patterns  of  faults  within  the  provinces  and  blocks  that  are  de- 
fined largely  by  major  Quaternary  structures.  Some  of  these 
structural  boundaries  are  covered  by  alluvium  or  young  rocks, 
and  so  sometimes  it  will  be  necessary  to  consider  earlier  struc- 
tural patterns  that  may  control  later  patterns.  In  some  parts  of 
the  state,  boundaries  are  not  well  defined  because  of  incomplete 
geologic  mapping;  in  these  isolated  cases,  the  boundaries  sug- 
gested may  need  later  modification. 


"Dwae  itnjctural  province*  ihoujd  not  be  cxmfujed  with  the  geomophic  provinces  by  which  the  state  ij  often  described.  Some  of  the  structural  province  boundaries  coincide  with  the 
Seoniorphic  provinces,  but  others  do  not 


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31 


Interaction  between  and  among  the  blocks  has  caused  second- 
ary stresses  within  individual  blocks.  The  internal  shearing  and 
rupturing  caused  by  these  stresses  have  resulted  in  the  formation 
of  many  sub-blocks.  Thus,  the  crust  of  California  is  comprised 
of  several  structural  provinces  which  form  a  mosaic  of  blocks 
and  sub-blocks  of  varying  sizes  and  shapes  interacting  in  a  com- 
plex fashion. 

Various  geologists  have  noted  fault  patterns  and  structural 
blocks  in  different  parts  of  California.  For  example,  Cummings 
(1976)  and  Garfunkel  (1974)  discussed  the  pattern  of  Cenozoic 
faults  in  the  Mojave  Desert  block,  and  Wright  (1976)  discussed 
the  late  Cenozoic  fault  patterns  and  stress  fields  in  the  Great 
Basin.  In  this  Bulletin,  however,  the  writer  points  out  fault  pat- 
terns and  blocks  throughout  the  state. 

In  this  discussion,  the  state  is  divided  into  eight  structural 
provinces,  containing  16  blocks  and  24  sub-blocks,  which  are 
defined  on  the  basis  either  of  predominant  fault  trends  or  of  the 
characteristics  of  faults  they  contain.  The  reader  is  asked  to  refer 
to  Plate  2  as  the  following  structural  blocks  and  sub-blocks  in 
California  are  defined  and  discussed. 


Predominant  Fault  Trends  Defining 
Structural  Provinces 

The  Quaternary  faults  in  California  can  be  grouped  into  spe- 
cific structural  provinces  according  to  the  predominant  trend  of 
the  faults.  Four  of  these  provinces  seem  to  be  limited  to  specific 
areas  with  rather  definite  boundaries,  while  four  additional 
structural  provinces  are  bounded  by  somewhat  less  definite 
boundaries,  and  contain  within  them  complex  or  multiple  fault 
trends  rather  than  a  single  dominant  fault  trend.  The  first  four 
structural  provinces  are  subdivided  into  a  number  of  blocks  and 
many  of  these  can  be  further  subdivided  by  subpeirallel  bounda- 
ries into  elongate  slices  or  sub-blocks. 


Major  Structural  Blocks  With 
Predominantly  Northwest  Faults 

The  Coast  Ranges  block  (la)  and  the  Peninsular  Ranges 
block  (lb)  (as  well  as  their  component  sub-blocks)  comprise 
Structural  Province  I,  which  is  characterized  by  faults  with  a 
strong  northwest  orientation  exemplified  by  the  trend  of  the  San 
Andreas  fault.  These  faults  interestingly,  all  display  right  lateral 
slip  (usually  with  a  vertical  component).  These  northwest- 
trending  faults  and  blocks,  however,  are  interrupted  in  the  south- 
em  part  of  the  state  by  faults  having  a  strong  eastward  trend  or 
transverse  direction,  which  define  Structural  Province  II. 


Coast  Ranges  Block 

The  eastern  boundary  of  the  Coast  Ranges  block  lies  beneath 
the  alluvium  of  the  Great  Valley,  and  the  western  boundary  is 
concealed  by  the  waters  of  the  Pacific  Ocean.  In  the  northern 
part  of  the  Coast  Ranges  block  where  the  east-trending  Mendo- 
cino fault  aligns  with  the  Eel  River  basin,  the  relationships  ap- 
pear to  be  very  complex  and  may  form  a  small  intervening  block. 
However,  everywhere  else  the  Coast  Ranges  block  is  dominated 
by  a  strong  northwesterly  structural  pattern.  The  southern 
boundary  of  the  Coast  Ranges  block  is  abruptly  terminated  by  the 
Big  Pine  fault  and  by  the  transverse  Structural  Province  II. 


Peninsular  Ranges  Block 

The  caslcrn  boundary  of  the  Peninsular  Ranges  block  is  de- 
fined by  the  Dillon  fault,  which  closely  parallels  the  San  Andreas 
fault  zone,  and  its  .southeast  projection  through  the  Orocopia 
and  Chocolate  Mountains  (fault  1 A  on  Plate  2 A).  This  fault  also 
marks  a  separation  between  the  prominent  northwest  trending 
faults  of  the  Peninsular  Ranges  block  and  either  the  east-trend- 
ing faults  m  the  Pinto  Mountains  sub-block  (II,)  or  the  diverse 
pattern  of  faults  in  the  Sonoran  Desert  block  (V).  The  western 
boundary  continues  offshore,  probably  as  far  as  the  Santa  Rosa- 
Cortes  Ridge.  The  southern  boundary  lies  in  Baja  California. 


Major  Structural  Block  Having 
Predominantly  East-Trending  Faults 

Transverse  Ranges  Block 

A  predominant  east-trend  or  transverse  fault  trend  is  charac- 
teristic of  Structural  Block  II.  This  block  is  composed  of  the 
Santa  Ynez,  the  San  Gabriel,  the  Banning,  the  San  Bernardino, 
and  the  Pinto  Mountains  sub-blocks.  All  the  major  faults  within 
these  sub-blocks  are  left  lateral  and/or  reverse  faults. 

Santa  Ynez  and  San  Gabriel  Sub-Blocks 

The  Santa  Ynez  sub-block  (11,)  is  bounded  sharply  on  the 
south  by  the  Santa  Monica-Raymond  Hill  fault  zone  and  on  the 
north  by  the  Big  Pine  fault  and  its  westward  projection.  The  San 
Gabriel  sub-block  (11,)  is  bounded  by  the  San  Andreas,  the 
Cucamonga,  and  the  San  Gabriel-Sierra  Madre  faults.  The  Santa 
Ynez  and  the  San  Gabriel  sub-blocks  very  abruptly  terminate  the 
northwest-trending  faults  of  the  Peninsular  Ranges  block  and 
those  in  the  southernmost  part  of  the  Coast  Ranges  block. 

Banning  Sub-Block 

The  wedge-shaped  Banning  sub-block  (IL)  is  enclosed  by 
parts  of  the  San  Andreas,  the  San  Jacinto,  and  the  Banning 
faults.  Both  the  east-trending  Cucamonga  and  the  Pinto  Moun- 
tains faults  abruptly  terminate  against  this  sub-block. 

San  Bernardino  Sub-Block 

The  San  Bernardino  sub-block  (IL)  and  the  Pinto  Mountains 
sub-block  (II,)  appear  to  be  offset  right  laterally  from  sub- 
blocks  11;  and  II,  by  the  San  Andreas  fault  zone.  The  San  Bernar- 
dino sub-block  is  bounded  on  the  north  by  an  east-trending 
thrust  fault,  on  the  west  by  the  San  Andreas  fault,  and  on  the 
south  by  the  Pinto  Mountains  fault.  The  eastern  side  of  this 
sub-block  is  not  well  defined  by  any  mapped  fault  but  is  mark- 
ed by  the  termination  of  the  San  Bernardino  Mountains. 
Cummings  (1976)  included  this  sub-block  with  his  Mojave 
Desert  block,  but  its  internal  transverse  structure  could  exclude 
it  from  the  Mojave  Desert  block,  at  least  in  recent  geologic  time. 

Pinto  Mountains  Sub-Block 

The  Pinto  Mountains  sub-block  (II,)  is  bounded  by  the  east- 
trending  left-lateral  Pinto  Mountain  and  Chiriaco  faults.  Mid- 
way between  these  faults  lies  another  left-lateral  fault,  the  Blue 


32 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Cut  fault,  which  may  be  considered  as  further  subdividing  the 
Pinto  Mountains  sub-block  (Plate 2 A). The  Dillon  fault  clearly 
forms  the  western  boundary.  The  southern  boundary  may  extend 
farther  south  toward  the  ChiKolate  Mountains  where  certain 
east-trending  faults  are  known.  However,  this  area  has  not  been 
mapped  in  detail,  so  the  southern  and  soulheastern  boundaries 
arc  not  precisely  defined. 

Major  Structural  Blocks  Characterized  By 
Northeast-Trending  Fault  Boundaries 

The  Oarlock  and  White  Wolf  faults  are  the  two  most  signifi- 
cant northeast-trending  faults  in  the  state  and  define  Structural 
Province  III.  which  consists  of  two  blocks.*  These  faults  are 
characteristically  left-lateral,  but  may  also  have  a  minor  reverse 
slip  component. 

Mojave  Block 

The  Mojave  block  (Ilia)  has  been  recognized  as  a  separate 
entity  for  a  long  time  and  was  discussed  in  some  detail  by  Hewett 
( 1954)  and  several  others  since  then.  The  wedge-shaped  Mojave 
block  is  bounded  by  the  Garlock  and  the  San  Andreas  faults  and 
on  the  south  by  east-trending  faults.  The  eastern  boundary  has 
not  been  mapped  in  detail,  but  appears  to  be  defined  by  the 
junction  of  the  predominantly  northwest-trending  faults  within 
the  Mojave  block  and  the  diversely  oriented  faults  in  the  Sonoran 
Desert  block  to  the  east.  Within  the  Mojave  block,  northwest- 
trending  right-lateral  faults  are  certainly  common  and  conspicu- 
ous, although  the  northeast  portion  of  the  block  is  dominated  by 
east-trep  jing  faults  and  may  be  a  separate  sub-block  as  suggested 
by  Garfunkel  (1974.  p.  1938). 

Tehachapi  Block 

The  Tehachapi  block  (Illb)  is  included  in  this  report  as  part 
of  the  same  structural  province  as  the  Mojave  block  because  it 
is  bounded  on  two  sides  by  northeast-trending  faults — the  Gar- 
lock  and  the  White  Wolf  faults.  It  is  mostly  comprised  of  granitic 
and  metamorphic  rocks  like  the  Sierra  Nevada,  but  is  offset  to 
the  southwest  from  the  main  Sierra  Nevada  block. 

Major  Structural  Blocks  Characterized  by 
North-Trending  Faults 

The  fourth  fault  direction  in  California,  that  gives  rise  to  Struc- 
tural Province  IV,  is  north-trending.  The  most  important  struc- 
ture of  this  trend  is  the  Sierra  Nevada-Owens  Valley  fault  zone. 
Several  subparallel  major  faults  of  this  same  orientation  (actual- 
ly, slightly  west  of  north)  make  up  several  blocks  within  this 
structural  province.  All  these  north-trending  faults  are  normal 
faults,  and  any  lateral  component  of  slippage  is  usually  right 
lateral. 

Kern  Canyon  Block 

One  of  the  blocks  is  the  Kem  Canyon  block  (IVa),  which  lies 
between  the  Kem  Canyon  fault  and  the  Sierra  Nevada-Owens 
Valley  fault  zone  Its  southern  end  is  uncertain  but  is  possibly 
bounded  by  a  northeastern  extension  of  the  White  Wolf  fault 
lrcnd(Plate2A). Faults  within  this  block, especially  in  the  Owens 


Valley-Bishop  area,  are  numerous  and  trend  almost  always 
north.  In  addition,  these  faults  align  with  the  long  north-trend- 
ing zone  of  active  faults  in  Nevada  which  extends  from  Owens 
Valley  into  Nevada  through  Cedar  Valley,  Fairview  Peak,  and 
Dixie  Valley. 

Panamint  and  Death  Valley  Blocks 

Due  east  of  the  Kern  Canyon  block  are  the  Panamint  and 
Death  Valley  blocks  (IVb  and  IVc).  They  are  more  crudely 
defined  than  the  other  blocks  of  the  structural  provinces  but  are 
well  expressed  in  part  by  the  north-trending  Panamint  Valley 
and  Death  Valley  fault  zones.  Within  these  blocks  are  numerous 
short  faults  which  characteristically  trend  northwest  and 
northeast.  These  conjugate  fault  directions  appear  much  more 
numerous  when  we  include  the  faults  designated  as  "pre-Quater- 
nary  or  age  unknown"  (Figure  7);  perhaps  some  or  many  of 
these  "older"  faults  may  also  be  found  on  closer  analysis  to  be 
of  Quaternary  age.  In  any  event,  the  conjugate  faults  within  these 
blocks  bounded  by  north-trending  faults  collectively  make  a 
pattern  with  a  preferred  northwest  and  northeast  orientation, 
with  no  sign  of  an  east-trending  direction.  Interestingly,  this  area 
appears  to  be  the  only  place  in  the  state  where  this  northwest- 
northeast  conjugate  system  is  so  well  developed — a  fact  suggest- 
ing that  it  is  acting  as  a  unit  to  a  specific  stress  system. 


Figure  7.  Numerous  short  NW  ond  NE  conjugate  toults  characteristic  of  the 
PonominI  and  Death  Valley  blocks  .  (thick  lines  =  Quaternary  faults,-  thin 
lines  =    pre-Quaternary  or  undated  faults) 


•An  wiclrnt  norttwait-IrmdinK  fault,  the  Stockton  fault,  lies  in  Ihr  w*»-iurf«cr  beneath  the  Cri-at  Valley,  but  ha-i  no  apparent  relationship  to  the  Quaternary  tectonics  discussed  here 


1985 


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33 


Warner  Block 

Another  prominent  block  with  characteristic  north-trending 
faults  is  the  Warner  Block  (IVd)  in  the  northeastern  comer  of 
the  state.  Most  prominent  is  the  Surprise  Valley  fault  and  the 
block-faulted  Warner  Range. 

East  Sierra  Block 

The  East  Sierra  block  (IVe)  has  a  well-defined  boundary  on 
the  west  side  formed  by  the  main  Sierra  Nevada  block,  but  only 
a  vaguely  defined  boundary  on  the  east  side  at  the  Walker  Lane 
in  Nevada.  This  block  is  characterized  by  block-faulting  with 
strike-slip  shearing. 

Cascade  Block 

The  Cascade  block  (IVQ,  in  the  northern  extremity  of  Cali- 
fornia, is  the  southern  tip  of  an  elongate  north-trending  block 
which  continues  for  many  miles  into  Oregon  and  Washington. 
It  is  principally  defined  by  a  north-trending  series  of  volcanoes 
that  may  be  controlled  by  deep  faults  or  fractures  along  which 
these  volcanoes  and  lavas  have  erupted. 

Corda  Block 

Finally,  offshore  of  northwestern  California  lies  another  block 
with  north-trending  faults.  This  appears  to  be  part  of  the  eastern 
edge  of  the  subducting  Gorda  block  (IVg). 


Major  Structural  Blocks  Characterized  By 
Other  Types  Of  Faults 

The  state  contains  four  other  structural  provinces,  which  are 
in  general  less  well  defined,  especially  by  Quaternary  structures, 
but  which  nevertheless  form  specific  areas  that  have  their  own 
si>ecial  characteristics. 

Sonoran  Desert  Block 

Structural  Province  V  forms  a  rather  large  region  which  is 
fairly  well  defined  on  the  west,  but  extends  eastward  into  Ne- 
vada, Arizona,  and  Mexico,  where  its  boundaries  have  not  been 
studied  in  detail.  Geomorphologically,  this  region  is  considered 
part  of  the  Mojave  and  Basin  Ranges  geomorphic  provinces, 
but  structurally  it  appears  to  form  a  separate  province — here 
called  the  Sonoran  Desert  block.  Its  eastern  boundary  may  be 
defined  by  the  Walker  Lane  in  Nevada  and  Arizona,  wherein  lies 
another  structural  province  with  north-trending  faults.  Thrust 
faults  are  known  in  the  Sonoran  Desert  block,  but  their  extent 
has  not  been  determined.  In  fact,  much  of  this  area  has  only  been 
mapped  by  reconnaissance,  and  so  further  analysis  at  this  time 
is  not  feasible. 

Sierra  Nevada  Block 

Structural  Province  VI  consists  of  the  Sierra  Nevada  block, 
which  has  long  been  recognized  as  a  major  structural  feature. 
Certainly  this  large  batholith  forms  a  resistant  block  and  serves 
in  some  places  as  a  buttress  and  elsewhere  as  a  ram  on  adjacent 
blocks.  Its  western  boundary  lies  beneath  the  Great  Valley.  Its 
eastern  boundary  is  clearly  marked  by  an  immense  scarp  in  some 


places  and  by  the  faulted  tcrrane  of  Structural  Province  IV.  The 
northeastern  boundary  with  the  Modoc  block  was  shown  by 
Durrell  (1965,  1966)  as  a  separation  of  an  area  of  relatively 
young  block  faulting  from  a  more  stable  mass.  The  northwestern 
boundary  is  a  complicated  and  vaguely  defined  junction  of  at 
least  four  blocks.  Further  work  in  this  area  should  help  to  clarify 
the  inter-relationships.  This  northwestern  portion  of  the  Sierra 
Nevada  block  also  contains  a  large  mass  of  the  older,  pre-bath- 
olith  rocks  through  which  trends  the  well-developed  fault  zone 
of  the  Melones  and  Bear  Mountain  faults.  At  the  south  end, 
these  faults  have  a  prominent  northwest  trend;  they  turn  due 
north  in  the  central  region  and  then  swing  northwest  again  at  the 
north  end.  This  fault  zone  widens  northward  and  splits  into 
several  branches.  The  faults  were  formed  in  pre-batholith  times 
but  renewed  activity  has  been  noted  along  parts  of  this  ancient 
zone  of  weakness  (Alt  and  others,  1977).  The  Oroville  earth- 
quake of  August  1975,  with  associated  ground  rupture,  for  ex- 
ample, illustrates  the  effects  of  a  modem  stress  field  acting  on  a 
very  old  zone  of  crustal  weakness. 

Klamath  Block 

Impinging  on  the  northwestern  end  of  the  Sierra  Nevada  block 
is  Structural  Province  VII,  the  Klamath  block.  This  structural 
unit  is  typified  by  numerous  ancient  thrust  faults.  No  Quater- 
nary faults  are  known  within  this  area  of  resistant  granitic  and 
metamorphic  rocks. 

Modoc  Block 

Lastly,  the  Modoc  block  forms  the  irregular,  anomalous 
Structural  Province  VIII.  It  is  characterized  by  numerous  Qua- 
temary  faults,  most  of  which  trend  northwest,  but  with  some 
conjugate  faults  that  trend  northeast,  and,  in  one  part  of  this 
province,  with  some  seemingly  arcuate  faults.  The  faults  are 
largely  in  young  volcanic  rocks,  but  their  relationship  to  this 
outpouring  of  lava  is  not  understood.  Two  long  and  significant 
faults  appear  within  this  unit — the  Likely  and  the  Honey  Lake 
faults.  The  Likely  fault  appears  to  have  a  right-lateral  strike-sUp 
component,  while  the  Honey  Lake  fault  is  mostly  normal  dip- 
slip.  Northwest-trending  fault  segments  line  up  with  the  Honey 
Lake  fault,  and  they  may  be  part  of  the  same  fault  zone  extending 
toward  Oregon.  This  northwest  trend  may  be  a  reflection  of  an 
underlying  stmctural  province  hidden  beneath  the  Modoc  lavas, 
or  it  may  be  the  result  of  a  totally  new  stress  field.  It  should  be 
pointed  out  that  only  reconnaissance  mapping  has  been  accom- 
plished in  most  of  this  area  and  that  most  of  the  faults  were 
largely  unrecognized  as  recently  as  20  years  ago. 

Coast  Ranges  Sub-Blocks 

Within  the  Coast  Ranges  block,  seven  sub-blocks  are  recog- 
nized. Four  of  these  sub-blocks  are  well-defined  and  are  bounded 
by  well-known  faults.  The  faults  are  parallel  for  the  greater  part 
of  their  length,  and  are  abruptly  terminated  at  the  southern  end 
by  the  Transverse  Ranges  block.  In  central  California ,  sev- 
eral adjacent  faults  converge  with  one  amother  forming  blocks 
having  remarkable  mirror-image  symmetry. 

Santa  Lucia  and  Cabilan  Sub-Blocks 

The  King  City-Rinconada  fault  separates  the  Santa  Lucia  and 
the  Gabilan  sub-blocks  ( la,  and  laj).  The  Santa  Lucia  sub-block 
is  bounded  on  the  west  by  the  inter-connection  of  the  Seal  Cove, 


34 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


the  San  Gregorio,  the  Sur.  and  the  Hosgri  faults,  and  the  Gabilan 
sub-block  is  bounded  on  the  east  by  the  San  Andreas  fault.  Note 
that  the  Seal  Cove  fault  converges  with  the  San  Andreas  to  the 
north.  Likewise,  a  short  extrapolation  of  the  northwest-trending 
King  City  fault  coincides  with  similarly  oriented  faults  under 
Monterey  Bay,  which  in  turn  are  aligned  with  a  northwest- 
trending  portion  of  the  Santa  Cruz  County  coastline  that  is 
probably  fault  controlled,  and  thus  converges  with  the  San  Gre- 
gorio fault.  To  the  south,  both  of  these  sub-blocks  terminate 
against  the  transverse  Big  Pine  fault  and  its  westward  extrapola- 
tion. 

San  Francisco  and  Berkeley  Sub-Blocks 

The  San  Francisco  and  Berkeley  sub-blocks  (lai  and  la,)  are 
separated  by  the  Hayward-Rtxigers  Creek-Maacama  fault  zone. 
The  San  Francisco  sub-block  is  bounded  by  the  San  Andreas 
fault  on  the  west;  the  Berkeley  sub-block  is  bounded  by  the 
Calaveras-Green  Valley  fault  zone  on  the  east.  The  Hayward 
fault  appears  to  converge  with  the  Calaveras  fault  to  the  south, 
and  likewise  the  Calaveras  fault  converges  with  the  San  Andreas 
fault  to  the  south.  It  is  interesting  to  note  the  symmetrical  rela- 
tion between  sub-blocks  la,  and  la,,  north  of  the  San  Andreas 
fault,  and  sub-blocks  la,  and  la,  south  of  the  San  Andreas  fault. 


the  continental  borderland  shown  on  the  Fault  Map  of  Califor- 
nia are  determined  to  be  Quaternary  upon  further  investigation; 
in  any  event,  all  these  offshore  faults  shown  are  at  least  of  late 
Tertiary  age. 

San  Clemenfe  and  Catalina  Sub-Blocks 

The  San  Clemente  sub-block  (lb,)  is  well  defined  on  the  east 
by  the  San  Clemente  fault  and  faults  lying  on  the  same  strike  to 
the  north.  The  western  boundary  appears  to  lie  among  the  faults 
along  the  Santa  Rosa-Cortes  Ridge.  The  Catalina  sub-block 
(lb.)  is  bounded  on  the  east  by  the  Thirty  Mile  Bank  and  the 
Catalina  Island  faults  and  on  the  west  by  the  San  Clemente  fault 
(faults  5,  5A,  and  6  on  Plate  2A). 

Pahs  Verdes  and  Inglewood-San  Diego  Sub-Blocks 

The  Palos  Verdes  sub-block  (lb.)  is  bounded  by  the  next 
major  northwest-trending  Quaternary  fault  to  the  east,  the  Palos 
Verdes  fault  and  its  offshore  extensions  on  strike  to  the  south. 
The  Inglewood-San  Diego  sub-block  (lb,)  is  defined  by  the 
Quaternary  Newport-  Inglewood-Rose  Canyon  fault  zone  on  the 
east  and  the  Palos  Verdes  fault  on  the  west. 


Diablo  and  Great  Valley  Sub-Blocks 

The  next  sub-block  to  the  east  is  the  Diablo  (la,),  defined  in 
pan  by  the  Ortigalita  fault  and  its  extrapolation  to  the  north.  Its 
southern  boundary  and  its  boundary  with  the  Great  Valley  sub- 
block  (Ia»)  to  the  east,  are  hypothetical;  they  have  been  drawn 
largely  on  the  basis  of  the  equidistant  fault  spacing  concept 
discussed  later. 

Stonyford  Sub-Block 

Lastly,  the  Stonyford  sub-block  (la,)  is  the  anomalous 
northeast  comer  of  the  Coast  Ranges  block.  Older  faults  have 
made  the  breaks  dividing  this  comer  from  the  main  block.  Al- 
though the  Bartlett  Springs  fault  on  the  west  side  of  this  sub- 
block  has  now  been  recognized  as  a  Quaternary  fault  (Hearn  and 
Donnelly,  personal  communication,  1977),  the  faults  within  the 
Stonyford  sub-block  appear  to  be  characterized  by  ancient  thrust 
faults.  On  the  basis  of  photo  interpretation  and  prominent  linea- 
ments, it  appears  that  the  Bartlett  Springs  fault  connects  with  the 
Grogan  fault  farther  north,  which  may  in  turn  join  with  a  promi- 
nent Quaternary  fault  offshore. 


Peninsular  Ranges  Sub-Blocks 

The  Peninsular  Ranges  block,  in  the  southern  part  of  the  state, 
is  readily  divisible  into  eight  sub-blocks.  These  eight  northwest- 
trending  sub-blocks,  without  exception,  terminate  against  the 
Transverse  Ranges  block  lying  to  the  north.  All  the  Peninsular 
Ranges  sub-blocks  in  California  and  offshore  are  remarkably 
parallel,  and  all  extend  southward  into  Baja,  California. 

Three  of  the  Peninsular  Ranges  sub-blocks  lie  almost  totally 
offshore  of  California,  and  definition  of  their  boundaries  is  large- 
ly dependent  on  the  ofTshore  geophysical  work  that  has  been 
accomplished  in  recent  years.  Although  the  Peninsular  Ranges 
sub-blocks  illustrated  on  Plate  2A  are  defined  by  Quaternary 
faults,  the  boundaries  are  re-enforced  by  the  patterns  of  the  older 
faults.  It  would  not  be  surprising  if  additional  offshore  faults  in 


Santa  Ana,  Riverside,  and  San  Jacinto    Sub  -Blocks 

The  Santa  Ana  (lb,).  Riverside  (IbJ,  and  San  Jacinto  (lb,) 
sub-blocks  have  remarkably  distinct  boundaries  formed  by  the 
Quaternary  Elsinore  fault,  the  San  Jacinto  fault,  and  the  San 
Andreas  fault  on  the  east  side  of  each.  A  possible  eighth,  narrow- 
sub-block  may  lie  east  of  the  San  Andreas,  bounded  by  the 
Dillon  fault  and  other  somewhat  older  faults  along  the  south- 
east-trend of  the  Dillon  fault  (fault  1 A  on  Plate  2A  ) . 


Sub-Blocks  Within  The  Modoc  Block 

The  Modoc  block  (VIII)  in  the  northeast  comer  of  the  state 
is  irregularly  shaped,  and  it  seems  to  be  characterized  by  numer- 
ous Quatemary  faults.  Many  of  these  faults  trend  northwest- 
wardly, but  some  also  strike  in  other  directions.  Mapping  of  this 
area  has  been  mostly  reconnaissance,  but  even  so,  the  fault  pat- 
terns suggest  some  tentative  subdivisions  that  are  shown  on  Plate 
5.  These  are  identified  as  the  Alturas,  Eagle  Lake,  Diamond 
Mountains,  and  Medicine  Lake  sub-blocks. 


Summary 

From  the  preceeding  discussion  and  by  consideration  of  the 
Structure  Map  of  California  (Plate  2  A),  the  basic  concepts  con- 
ceming  predominant  fault  trends  and  the  structural  provinces 
they  define  may  be  summarized  as  follows: 

1.  The  state  is  divisible  into  eight  structural  provinces,  each 
containing  faults  and  folds  of  a  characteristic  trend  or 
pattern,  or,  in  a  few  cases,  two  dominant  conjugate  direc- 
tions. 

2.  The  structural  provinces  are  also  divisible,  so  that  the 
state  appears  to  be  broken  into  a  complicated  mosaic  of 
fault  blocks. 

(a)     Each  block  appears  to  be  acting  as  a  unit,  but  also 
interacting  with  adjacent  blocks. 


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35 


(b)  Stresses  within  each  block  (particularly  the  larger 
blocks)  develop  secondary  faults  which  define 
sub-blocks. 

(c)  The  blocks  and  sub-blocks  appear  to  be  best  de- 
fined in  the  southern  part  of  the  state  where  the 
rocks  are  well  exposed  and  where  the  most  detailed 
mapping  has  been  done.  The  blocks  in  the 
northernmost  part  of  the  state  are  less  well  defined; 
where  the  forest  cover  is  most  dense  and  the  map- 
ping less  detailed,  the  block  boundaries  are  least 
known. 

3.  Most  of  the  blocks  are  bounded  and  characterized  by 
major  Quaternary  faults  of  great  linear  extent.  In  a  few 
cases,  major  pre-Quatemary  structures  define  blocks 
having  common  structural  characteristics. 

4.  With  only  a  few  exceptions,  all  Quaternary  and  older 
faults  and  folds  within  a  block  or  sub-block  are  confined 
to  that  block  and  never  cross  its  boundaries,  even  when 
the  fault  or  fold  may  cross  the  entire  block  or  sub-block. 

5.  The  most  common  fault  trend  in  California  is  northwest 
with  east  being  secondary.  Northeast-trending  faults  are 
relatively  few  but  include  two  major  faults — the  Garlock 
and  the  White  Wolf.  North-trending  faults  are  not  com- 
mon and  usually  form  more  complex,  segmented  fea- 
tures. 


6.  (a) 
(b) 
(c) 
(d) 


All  major  northwest-trending  Quaternary  faults  are 
right  lateral  (usually  with  a  vertical  component).* 

All  major  east-trending  Quaternary  faults  are  left 

lateral  and/or  are  reverse  faults. 

All  major  northeast-trending  Quatenary  faults  are 

left  lateral  and/or  are  re\erse  faults. 

North-trending    Quaternary    faults    are    normal 

faults  (with  mostly  right  lateral  components). 


FAULT  COUPLES 

An  interesting  observation  about  sub-blocks  can  be  noted.  An 
apparent  "couple  effect"  is  generated  in  the  block  between  two 
parallel  strike-slip  faults.  In  this  situation,  diagonal  breaks  occur 
between  the  bounding  faults,  forming  a  family  of  diagonal  faults 
with  a  consistent  orientation.  Good  examples  of  this  can  be  seen 
in  the  northern  Coast  Ranges  between  the  San  Andreas  and  the 
Rodgers  Creek-Healdsburg  faults  or  in  the  Transverse  Ranges 
between  the  San  Andreas  and  San  Gabriel  faults  (Figures  8  and 
9).  Still  other  examples  can  be  seen  in  other  parts  of  the  state, 
especially  in  the  western  part  where  the  major  faults  are  strike- 
slip.  It  appiears  that  most  of  the  diagonal  faults  have  no  Quater- 
nary displacement  and  that  the  bounding  faults  do  have  Quater- 
nary displacement.  Perhaps  this  is  because  the  diagonal  faults  are 
activated  only  after  a  long  period  of  time  when  the  confining 
stress  finally  exceeds  the  strength  of  the  crustal  materials.  If  so, 
the  stress  on  the  diagonal  faults  is  intermittantly  accumulated 
and  relieved,  while  the  confining  parallel  faults  undergo  more 
frequent  strike-slip  movement. Hence,  it  should  not  be  surprising 
if  an  occasional  stress  release  occurs  on  some  of  these  diagonal 


faults — in  fact,  many  of  the  earthquake  epicenters  not  lying  on 
major  faults  could  represent  release  of  stress  on  such  diagonal 
fauhs  (Plate  2D). 

There  are  places  between  major  parallel  strike-slip  faults 
where  no  diagonal  fault  pattern  has  developed — for  example, 
between  the  northern  parts  of  the  Elsinore  and  San  Jacinto  faults 
or  between  the  Elsinore  fault  and  the  Newport-Inglewood-Rose 
Canyon  fault  zone.  However,  an  examination  of  the  Geologic 
Map  of  California  at  these  places  reveals  the  presence  of  exten- 
sive bodies  of  Mesozoic  and  older  granitic  and  metamorphic 
rocks.  These  rocks  probably  would  tend  to  resist  such  diagonal 
shearing  and  focus  the  release  of  stress  along  the  block  bounda- 
ries. Another  place  where  the  absence  of  diagonal  faults  is  espe- 
cially noticeable  is  in  the  Gabilan  block,  which  has  virtually 
no  intra-block  faults  and  which  is  characterized  by  the  granitic 
rocks  of  the  Gabilan  Range  between  the  strike-slip  San  Andreas 
and  King  City-Rinconada  faults  (Figure  10).  Southeast  of  the 
exposed  granitic  rocks  of  the  Gabilan  Range,  there  is  also  a 
virtual  absence  of  faults,  but  the  rocks  here  consist  mostly  of  a 
thin  layer  of  late  Tertiary  sedimentary  rocks  overlying  the  rigid 
granitic  rocks.  Here,  however,  gentle  folds  in  the  overlying  sedi- 
mentary rocks,  exhibit  north  northwest-trending  axes  along  the 
direction  of  the  expected  diagonal  faults. 


EN  ECHELON  FAULTS 

Within  the  northern  Coast  Ranges,  the  major  Quaternary 
strike-slip  faults  which  bound  certain  sub-blocks  commonly  dis- 
play a  remarkably  consistent  right-stepping  en  echelon  pattern. 
For  example,  the  Hayward,  the  Rodgers  Creek,  the  Healdsburg, 
and  the  Maacama  faults  each  appear  to  be  a  successive  right- 
stepping  continuation  of  a  principal  fault  zone  bounding  the 
eastern  edge  of  the  San  Francisco  sub-block.  And  the  Calaveras, 
the  Concord,  the  Green  Valley,  and  the  unnamed  faults  to  the 
north  appear  to  be  a  successive  right-stepping  continuation  of 
another  major  fault  zone  bounding  the  eastern  edge  of  the  Berke- 
ley sub-block.  Both  of  these  sub-blocks  are  characterized  by 
diagonal  shear  faults.  In  a  similar  fashion,  the  Bartlett  Springs 
fault  lines  up  with  right-stepping  lineaments  northward  into 
Trinity  and  Humboldt  counties;  this  alignment  suggests  the  loca- 
tion of  heretofore  unrecognized  faults  bounding  the  Stonyford 
sub-block. 


REGULARITY  OF  FAULT  SPACING 

The  spatial  geometry  of  the  major  Quaternary  faults  reveals 
another  interesting  relationship.  This  concerns  their  remarkable 
parallehsm  and  uniformly  spaced  intervals  over  great  distances. 
This  is  particularly  evident  in  the  sub-blocks  of  the  Coast  Ranges 
and  Peninsular  Ranges  structural  blocks.  In  the  Coast  Ranges 
block,  the  spacing  between  the  major  faults  bounding  the  sub- 
blocks  ranges  from  approximately  33  to  39  km  along  lengths  of 
well  over  240  kilometers  (Plate  2B). Within  the  onshore  portion 
of  the  Peninsular  Ranges  block,  three  sub-blocks  vary  from  37  to 
42  km  in  width  (except  for  the  southern  part  of  the  Santa  Ana 
block,  which  is  as  much  as  72  km  wide;  however,  there  the 
southern  California  batholith  widens  to  its  greatest  extent).  Off- 
shore the  spacing  interval  is  32  to  42  km  with  the  Palos  Verdes 
fault  appearing  to  divide  a  32  km  wide  block  into  two  sub-blocks. 

'  \t  fir^t  cLiiic*',  It  appears  th.tt  thi-  fjiiiiK  of  ^.horl  norlhwrsl-trciuliii).:  Titills  in  iiorthrrii  ( ;.iliforiii.i  known  .i\  Ihi-  I'.iskt-nl.i.  I'lldtT  Ort'fk  .(tut  Oold  l-ork  f.tults.  «hich  diNpl.ict^  I/)\%er 
( .'f c't.ic*-<>ns  .ind  Jnr.isMC  rncks  left  Litcr.ill> .  is  .in  oxcoplion  to  the  b.isic  cnncrpl  prrsnili-d  horr  .ilxiiil  iKirthwcNl  Irrnilin^  f.llilts  Im'iiik  rinht  l.it(T;il  llowrxrr.  if  thru-  f;uilts  are 
mtrrprotod  .!_«.  tear  fallll\  off  the  (".Oiist  Rani^c  thriisl.  where  the  (;oast  Ranjfr  thriiNt  liKips  arolilKl  the  Klani.ith  Monnl.iiiis  Iwfore  hea{lin><  south,  then  these  northwest  faults  are 
a  special  case  and  arc  Ix'hasinK  a.s  tear  faults  of  this  orientation  would  Ix*  e\jx*cted  to.  In  addition,  thes*-  faults  .irc  \erv  oUI  and  h.i\e  no  ri-coKni/ahlc  Qiiaternars  dis|ilacenicnt 
(Jones  and  Insin,  1971). 


36 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


\  •.    V      c 


Figure  8.      Diagonal  faults  formed  between  two  major  strike-slip  faults,  the  Son  Andreas  ond  the  Rodgers  Creeli-Heoldsburg  faults. 


The  major  faults  bounding  the  three  adjacent  north-trending 
structural  blocks — Kern  Canyon,  Panamint,  and  Death  Valley 
— also  display  roughly  equidistant  spacing.  Two  of  these  blocks 
are  about  50  to  53  km  wide,  while  the  third  is  about  42  km  wide 
over  distances  of  over  160  km. 

It  appears  that  regularity  of  spacing  between  major  faults, 
repeated  in  many  parts  of  the  state,  must  be  more  than  a  coinci- 
dence. It  suggests  that  the  rigidity  of  the  earth's  crust  is  behaving 
in  some  consistent  fashion  related  to  the  strength  of  the  crustal 
or  even  sub-crustal  materials  and  to  the  direction  of  deep  stresses 
applied  to  the  structural  blocks.*  If  such  be  the  case,  then  the 
existence  of  faults  in  unmapped  areas  (such  as  some  offshore 
areas)  and  in  incompletely  mapped  areas  (such  a.s  in  northwest- 
em  and  southeastern  California)  might  be  predicted  by  extrapo- 
lation of  known  faults  by  maintaining  equidistant  spacing 
between  them.  For  example,  the  northwestward  continuation  of 
the  San  Francisco  and  Berkeley  sub-blocks  into  Mendocino 
County  would  therefore  be  expected,  by  extension  of  the  Maaca- 
ma  and  Barilctt  Spnngs  faults  (with  right-stepping  en  echelon 
offset).  The  continuation  of  an  accompanying  diagonal  fault 
system  between  these  strike-slip  faults  would  also  be  anticipated; 
and,  in  fact,  topographic  lineaments  and  incompletely  mapp>ed 


faults  (see  Fault  Map  of  CaUfomia)  strongly  suggest  such  a 
continuation  of  both  the  strike-slip  faults  and  the  diagonal  fault 
system. 

To  extend  precisely  the  mapping  of  faults  paralleling  the  San 
Andreas  trend  northward  into  the  terra  incognita  of  the  northern 
Coast  Ranges  block  will  be  difficult  because  of  the  existence  of 
numerous  and  gigantic  landslides.  However,  one  thing  is  certain 
— the  major  faults  coming  up  from  the  south  must  continue  into 
this  landslide  terrane.  Indeed,  many  of  the  landslides  are  in  all 
probability  a  reflection  of  the  weak  rock  crushed  by  the  suspect- 
ed faults.  The  strong  northwest-trending  lineaments,  expresed  by 
the  major  river  drainages,  are  an  indication  of  the  structural 
grain  of  the  country.  Unfortunately,  the  river-undercutting  of 
the  steep  slopes  in  this  high  rainfall  area,  releases  the  landslides 
which  can  easily  mask  fault  traces. 

Twenty-five  years  ago,  H.W.  Menard  (1955,  p.  1172)  noted 
the  regularity  of  fault  spacing  in  the  tx;ean  floor  off  California 
and,  on  the  basis  of  this  regularity,  predicted  the  existence  of 
additional  offshore  fracture  zones.  "Four  fracture  zones  have 
been  discovered,"  writes  Menard,  "and  others  may  be  found  as 
more  echograms  become  available  from  other  regions  in  the 
Pacific."  Figure  1 1  is  Menard's  map  showing  the  location  of 


•Upon  cofnpiplion  of  thu  nianuKnpt.  in  which  the  wnlrr  independently  developed  the  ideas  of  equidiitani  fault  spacing  m  C^ifornia.  he  came  upon  foreign  reports  describing  this 
phmocnenon  in  other  paru  of  the  world  Kspecially  noteworthy  are  papen  by  j.  Kuttna  ( 1966)  and  Radan  Kvet  ( 1974}  In  these  papers  the  authors  describe  examples  of  equidistant 
rupture  lystetiu  In  Czechoalovalda.  Austria,  Scotland,  and  Sardinia. 


IPSS 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


37 


38 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


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1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


39 


these  four  fracture  zones.  Speaking  of  other  likely  fracture  zones, 
Menard  (p.  1172)  writes: 

Possible  locations  are  about  600  miles  north  of  the  Mendo- 
cino fracture  zone,  midway  between  the  Murray  and  Clar- 
ion fracture  zones,  and  about  600  miles  south  of  the 
Clipperton  fracture  zone.  These  positions  are  suggested  by 
the  regular  spacing  of  the  zones. 

The  most  probable  position  for  another  fracture  zone  is 
midway  between  the  Murray  and  Clarion  fracture  zones.  A 
zone  at  this  location  would  give  a  regular  unit  spacing  for 
all  the  zones  from  Mendocino  to  Clipperton  rather  than  a 
unit  spacing  between  the  northern  and  southern  pairs  and 
double  the  unit  spacing  between  the  middle  pair. 


As  a  matter  of  fact,  later  work  has  proved  Menard's  prognostica- 
tion correct.  Figure  1 2  shows  the  configuration  of  the  same  area 
as  Menard's,  but  is  based  on  much  additional  data  collected  at 
a  later  date.  Note  how  the  equally-spaced  faults  have  been  dis- 
covered. Of  course,  the  offshore  crustal  blocks  between  Menard's 
fracture  zones  are  several  orders  of  magnitude  larger  than  the 
sub-blocks  herein  described  for  onshore  parts  of  California.  The 
offshore  blocks  are  merely  presented  here  as  an  example  of  crus- 
tal materials  undergoing  stress,  which  deform  in  a  more  or  less 
uniform,  predictable  fashion. 

Menard  also  saw  some  possible  correlation  between  the  off- 
shore fracture  zones  and  the  geologic  provinces  on  the  conti- 
nents. He  felt  it  weis  particularly  significant  that  the  Great  Valley 
and  the  Sierra  Nevada,  as  well  as  other  geologic  provinces  south 
of  California,  all  appeared  to  be  terminated  at  their  northern  and 
southern  ends  by  the  onshore  continuation  or  projection  of  off- 
shore fracture  zones. 


SUMMARY  ON  FAULT  GEOMETRY 

The  following  facts  can  be  stated  about  the  geometry  and 
distribution  of  sub-blocks,  fault  couples,  and  fault-spacing  regu- 
larity: 

1.  Each  sub-block  has  remarkably  parallel  boundaries  for 
great  distances. 

2.  (a)     Each  sub-block  in  the  southern  Coast  Ranges 

abruptly    terminates    against    the    Transverse 
Ranges  block. 

(b)  Each  sub-block  in  the  northern  Peninsular 
Ranges  likewise  abruptly  terminates  against  the 
Transverse  Ranges  block. 

(c)  The  northern  termination  of  two  Coast  Ranges 
sub-blocks  (I,)  and  la,)  by  convergence  is  sym- 
metrical with  the  southern  termination  by  con- 
vergence of  two  other  contiguous  ccniral  Coast 
Ranges  sub-blocks  (la,  and  Ijl,),  that  is,  the  Seal 
Cove-San  Gregorio  fault  converges  with  the  San 
Andreas  and  with  the  projected  Rinconada-King 
City  fault  zone,  while  the  Green  Valley-Calaveras 
fault  zone  converges  with  the  San  Andreas  and 
with  the  Rodgers  Creek-Hayward  fault  zone. 

3.  (a)     Most  sub-blocks  bounded  by  strike-slip  faults 

contain  diagonal  faults  that  may  be  a  result  of  a 
couple  effect  whereby  diagonal  shears  are  formed 


in  the  block  between  the  bounding  strike-slip 
faults, 
(b)  Where  diagonal  faults  do  not  develop,  or  are  not 
well  developed,  between  parallel  strike-slip  faults, 
the  reason  could  be  that  resistant  granitic  and 
mctamorphic  rocks  lie  at  or  near  the  surface 
between  the  bounding  strike-slip  faults. 

4.  Major  Quaternary  strike-slip  faults  bounding  sub- 
blocks  in  the  central  Coast  Ranges  display  a  consist- 
ent right-stepping  en  echelon  pattern. 

5.  Spacing  between  the  major  parallel  Quaternary  faults 
shows  a  remarkably  uniform  interval. 

(a)  In  the  Coast  Ranges  block  this  equidistant  spacing 
interval  in  five  sub-blocks  ranges  from  33  to  39 
km  over  distances  in  excess  of  240  km. 

(b)  In  the  Peninsular  Ranges  block,  the  equidistant 
spacing  interval  ranges  from  32  to  42  km  in  five 
sub-blocks. 

(c)  Where  spacing  intervals  apjjear  to  vary,  they  oc- 
cur as  a  multiple  of,  or  equal  fractional  parts  of, 
the  regular  interval. 

(d)  Three  adjacent  north-trending  blocks  east  of  the 
Sierra  Nevada  block  approximate  equidistant 
spacing,  two  being  about  52  km  wide  and  the 
third  42  km  wide. 

(e)  Regularity  in  fault  spacing  has  been  noted  before 
in  offshore  California  areas  by  Menard  and 
served  as  a  useful  concept  in  correctly  predicting 
the    existence   of  additional    offshore    fracture 


FAULTING  AND  PATTERNS  OF 
SEISMICITY 

California  is  situated  within  a  mobile  belt  of  rocks  on  the 
boundary  between  the  Pacific  and  North  American  plates.  Here 
the  rocks  are  highly  folded  as  well  as  faulted,  and  in  places  are 
marked  by  numerous  volcanoes,  some  of  which  have  been  active 
in  historic  time.  The  state  is  also  part  of  the  well-known  circum- 
Pacific  earthquake  belt,  now  recognized  as  coinciding  with  inter- 
connecting plate  boundaries  around  the  Pacific  Ocean.  As  such, 
it  should  be  no  surprise  that  California  has  had,  and  will  contin- 
ue to  have,  numerous  earthquakes. 

Relationship  of  Epicenters  To  Faults 

Various  inaccuracies  are  inherent  with  epicenter  maps,  and 
most  epicenter  patterns  appear  more  or  less  randomly  positioned 
in  relation  to  individual  faults.  However,  with  care,  some  rela- 
tionships can  be  observed  between  faults  and  earthquake  epicen- 
ters of  certain  magnitudes.  For  example,  almost  all  of  the 
earthquakes  of  magnitude  6.0  and  greater  in  the  last  75  years 
(see  Plate  2C) have  epicenters  that  are  on  or  near  major  Quater- 
nary faults.  In  a  few  cases  where  this  relationship  does  not  seem 
to  exist,  the  epicenter  locations  could  be  suspect,  for  they  may 
have  been  far  from  the  seismic  networks  existing  at  the  time. 
(These  earlier  locations  are  often  rounded  off  to  the  nearest 
degree,  half-degree,  or  quarter-degree  latitude  and  longitude). 

Two  earthquake  events  in  the  magnitude  6  range  that  may  not 
be  related  to  major  Quaternary  faults  are  the  1947  Manix  and 
the  1966  Truckee  earthquakes.  Although  the  magnitude  6.2 


40 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Figure  U.      Fracture  zones  illustrated  by  Menard   (1955). 


ES 


MS 


Figure  12.      Port  of  a  tectonic  mop  of  the  world  (Condie,  1976)  including  the  some  oreo  illustrated  by  Menard  25  years  previously  (compore  with  Figure  11). 
Note  nearly  equol  spacing  between  Menard's  faults  and  additional  discoveries. 


1985 


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41 


Manix  earthquake  is  associated  with  the  Manix  fault,  along 
which  ground  rupture  occurred  for  a  distance  of  about  1 .6  km 
(one  mile),  the  overall  length  of  this  fault  is  probably  no  greater 
than  14.5  km  (nine  miles) — hardly  a  major  California  fault. 
Indeed,  from  the  aftershock  distribution,  which  was  nearly  at 
right  angles  to  the  Manix  fault,  Richter  (1958,  p.  517-518)  felt 
that  the  ground  breaks  observed  along  the  Manix  fault  were 
actually  the  effect  of  the  earthquake,  and  that  the  earthquake 
was  presumably  caused  by  subsurface  movement  along  a  buried 
fault  as  defined  by  the  aftershock  distribution.  The  magnitude 
6.0  Truckee  earthquake  is  also  not  clearly  associated  with  a 
major  Quaternary  fault,  although  ground  cracking  in  the  area 
was  aligned  for  about  16  km  (ten  miles).  However,  the  area  still 
is  relatively  poorly  mapped,  and  may  contain  unrecognized 
faults  of  significance. 

Earthquakes  of  less  than  magnitude  6,  which  of  course  are  far 
more  numerous,  show  less  close  correspondence  with  major 
Quaternary  faults.  Reasons  for  this  less  frequent  relationship 
include:  (a)  inaccuracies  in  location  of  pre- 1932  epicenters,  (b) 
inaccuracy  of  epicenter  locations  owing  to  the  great  distance 
from  networks  existing  at  the  time,  and  (c)  possibility  that  many 
of  the  smaller  earthquakes  may  simply  be  minor  crustal  adjust- 
ments within  the  various  interacting  crustal  blocks  and  sub- 
blocks  (as  described  in  the  previous  section  on  fault  patterns  p. 
31),  and  hence  are  not  occurring  along  breaks  exposed  at  the 
surface.  We  should  also  keep  in  mind  that  inchned  faults,  such 
as  thrust  faults,  do  not  give  rise  to  epicenters  which  project 
vertically  to  the  fault's  surface  exposure.  For  example,  the  epic- 
enters of  the  main  1971  San  Fernando  earthquake,  and  its  after- 
shocks, plot  well  to  the  north  of  the  trace  of  the  inclined  San 
Fernando  fault. 

A  study  of  the  fault-epicenter  map  (Plate  2D)  also  reveals  a 
certain  number  of  major  Quaternary  faults  without  any  apparent 
relation  to  earthquake  epicenters.  For  example,  in  the  northeast- 
em  part  of  California,  there  are  many  Quaternary  faults  but  very 
few  epicenters.  This  is  perhaps  because  the  setting  is  an  area  of 
extensive  volcanic  outpourings.  The  extensive  faulting  here  may 
have  originated  from  a  shallow,  short-term  cause  such  as  local 
land  collapse  due  to  volcanic  activity.  If  so,  repeated  movements 
on  most  of  these  faults  would  not  be  expected.* 

Many  currently  "quiet"  faults  in  other  parts  of  the  state, 
however,  are  likely  to  be  dormant  or  "locked"  portions  of  active 
faults.  For  example,  long  segments  of  the  San  Andreas  fault  that 
broke  in  1857  or  in  1906  do  not  today  have  associated  epicenters. 
We  also  know  from  other  parts  of  the  world,  such  as  China, 
Japan,  and  the  Mediterranean,  where  the  seismic  record  extends 
over  a  period  of  several  thousand  years  (Allen,  1975),  that  the 
200  years  of  historical  record  and  90  years  of  instrumental 
record  of  California  earthquakes  is  far  from  adequate  for  es- 
timating fault  activity.  Seismic  gaps  of  several  hundreds  of  years 
are  not  uncommon  in  the  long-term  records  from  these  ancient 
cultures,  and  hence  our  brief  California  record  must  be  used  with 
proper  caution  in  evaluating  the  potential  for  recurring  seismici- 
ty  on  seemingly  "dead"  Quaternary  faults. 


Relationship  Of  Surface  Rupture  To 
Earthquake  Magnitude 

In  general,  earthquakes  in  Cahfomia  of  magnitude  6  and 
greater  are  accompanied  by  surface  fault  rupture,  but  there  are 
exceptions.  The  data  in  Table  5  (1900-1974)  show  a  one-to-one 


Table  5.      California  Seismic  Record  for  75  Years. 


Earthquakes 

-   1900-1974 

Surface  Ruptures 

Magnitude 

No.  of  Events 

No.  of  Occurrences 

(Excluding 

(See  Table  4, 

offshore) 

Part  A) 

8-h 

1 

1 

7-7.9 

r 

1 

6^.9 

31 

8 

5-5.9 

238 

5 

<5 

— 

2 

•  The  1940  Imperial  earthquake,  which  for  years  was  reported  as  magnitude  7.1.  has  not 
been  included  because  more  recent  calculations  by  the  California  Institute  of  Technology 
show  this  event  as  magnitude  6,7  (Hileman  and  others.  1973). 


relationship  between  surface  faulting  and  earthquakes  for  magni- 
tudes 7  and  8.  The  earlier  historical  period  before  1900  (Table 
4,  Part  A)  adds  two  more  earthquakes  of  estimated  magnitude 
8  and  three  estimated  magnitude  7  earthquakes  associated  with 
surface  rupturing.  However,  of  3 1  magnitude  6  earthquakes  that 
occurred  during  the  /POO- 7974  interval  in  California  (excluding 
those  offshore),  only  eight  are  clearly  known  to  have  had  as- 
sociated surface  ruptures.  Of  course,  most  of  these  magnitude  6 
tremors  without  known  surface  ruptures  occurred  in  the  first 
part  of  the  century  when  locating  events  was  less  precise.  Also, 
many  of  the  earthquakes  occurred  in  very  sparsely  populated 
parts  of  the  state,  and  could  have  had  surface  ruptures  that  were 
not  observed  or  reported.  In  recent  years,  however,  with  vastly 
improved  and  telemetered  seismic  networks,  any  earthquake  of 
the  size  expected  to  break  ground,  no  matter  in  what  remote  part 
of  the  state,  is  immediately  examined  by  seismologists  and  geolo- 
gists from  the  Division  of  Mines  and  Geology  and  other  organi- 
zations and  institutions. 

Below  magnitude  6,  only  a  few  earthquakes  are  known  to  have 
broken  ground  even  though,  on  occasion,  earthquakes  in  Cali- 
fornia of  magnitudes  as  small  as  4.7  and  even  3.6  have  had 
accompanying  surface  ruptures  (Table  4,  Part  A).  Very  recent- 
ly, earthquakes  of  magnitude  4  to  4.6  that  occurred  in  the  Mount 
Shasta  area  produced  more  than  two  kilometers  ( 1 .2  miles)  of 
discontinuous  surface  cracks. 

Faults  With  Recurring  Earthquake  Activity 

Table  4,  Part  A  shows  that  19  out  of  30  well-documented 
historical  earthquakes  associated  with  surface  rupture  in  Califor- 
nia have  occurred  on  the  San  Andreas  fault  system.  They  include 
nine  on  the  San  Andreas  proper;  two  each  on  the  Hayward,  San 
Jacinto,  and  Calaveras  faults;  three  on  the  Imperial  fault;  and 
one  on  the  Superstition  Hills  fault — all  of  which  are  considered 
part  of  the  right-lateral  San  Andreas  fault  system.  Of  the  faults 
along  which  occurred  the  remaining  1 1  historical  earthquakes 
associated  with  surface  rupture,  none  has  had  a  recurrence. 
Thus,  the  San  Andreas  is  by  far  the  most  active  fault  system  in 
the  state. 

In  recent  years,  it  has  been  recognized  that  California  is  domi- 
nated by  strike-slip  faults  of  which  the  San  Andreas  system  is 
pre-eminant.  However,  as  far  as  seismic  hazards  are  concerned. 


•Certain  faults  in  this  region,  however,  such  as  the  throughgoing  Likely  fault  (which  shows  evidence  of  strike-slip  movement  and  for  which  aeron^agnetic  data  suggest  it  to  be  a  m4)or 
fiiult  feature)  may  behave  difterently  from  the  regional  swarm  of  faults.  Likewise,  the  Surprise  Valley  fault,  which  is  a  major  normal  fault  with  several  htindred  meters  of  vertical 
slip,  must  have  undergone  several  periods  of  movement 


42 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


one  of  the  largest  earthquake  events  observed  in  Cahfomia,  the 
1872  Owens  Valley  earthquake,  was  associated  with  a  fault  hav- 
ing a  dominantly  normal  (vertical)  displacement  history.  In 
addition,  two  very  disastrous  earthquakes  have  occurred  on 
predominantly  thrust  type  faults — the  San  Fernando  earthquake 
of  1971  and  the  Arvin-Tehachapi  earthquake  of  1952. 

Patterns  of  Seismicity 

Although  earthquake  epicenters  occur  in  most  parts  of  Cali- 
fornia, greater  concentrations  do  appear  in  certain  areas  or  along 
certain  fault  zones.  For  example,  the  west -trending  Mendocino 
fault  zone  clearly  marks  a  boundary  between  an  area  of  great 
seismicity  on  the  north  and  a  quiescent  area  to  the  south.  The 
San  Andreas  fault  for  at  least  180  miles  (288  km)  south  of  San 
Francisco,  and  the  Hayward  and  Calaveras  branches  are  all  well 
marked  by  numerous  epicenters;  in  fact,  microseismic  earth- 
quake monitoring  by  the  U.S.  Geological  Survey,  with  its  close- 
order  network  in  the  San  Francisco  Bay  area,  shows  an  even 
closer  relationship  of  seismicity  to  these  faults  (Figure  5).  The 
San  Andreas  system  in  southern  California  also  displays  a  close 
relationship  to  earthquake  epicenters,  especially  the  San  Jacinto 
branch  and,  to  a  lesser  degree,  the  southern  and  northern  parts 
of  the  Elsinore  fault.  The  Newport-Inglewood  fault  zone  is  a 
well-marked  trend  even  though  no  clearly  visible,  continuous, 
historic,  or  even  Quaternary  fault  rupture  is  present  at  the  sur- 
face. The  1952  Arvin-Tehachapi  earthquake  and  its  numerous 
aftershocks  are  clearly  related  to  the  White  Wolf  fault  when 
consideration  is  made  for  the  dip  of  the  fault.  There  is  also  a  very- 
conspicuous  north-trending  concentration  of  epicenters  along 
the  118°  meridian  from  Nevada  extending  south  into  the  Owens 
Valley  of  California,  marking  the  historic  ruptures  on  the  Pleas- 
ant Valley  (1915),  Dixie  Valley  (1954),  Rainbow  Mountain 
(1954),  Fairview  Peak  (1954),  Cedar  Mountain  (1932),  Excel- 
sior Mountain  (1954),  the  Owens  Valley  (1872)  faults  (Table 
4,  Parts  A  and  B).  This  particular  seismic  zone  has  been  noted 
in  previous  studies:  it  was  called  the  "118°  Meridian  Seismic 
Zone"  by  Slemmons  and  others  (1965)  and  the  "Nevada  Seismic 
Zone"  by  Gump>er  and  Scholz  (1971). 

The  epicenter  map  shows  what  appear  to  be  several  aseismic 
areas  within  the  state  (  Plate  2C  and  2D ).  In  the  eastern  Mojave 
Desert  area,  from  the  Ludlow  fault  eastward  to  the  Colorado 
River,  there  is  a  total  absense  of  earthquakes  of  magnitude  4  or 
greater;  in  this  area,  also,  almost  no  faults  having  evidence  of 
Quaternary  movement  have  been  recognized.  It  may,  however, 
be  too  early  to  conclude  that  this  is  truly  an  aseismic  area  be- 
cause: (1)  our  historic  record  is  very  short  in  years;  (2)  owing 
to  its  extremely  sparse  settlement,  the  area  has  until  very  recently 
been  far  from  seismic  networks  capable  of  recording  smaller 
earthquakes;  (3)  the  short  observational  period  may  not  reflect 
the  long-term  seismic  history,  and  the  faults  in  the  area  may 
in  fact  be  temporarily  dormant;  (4)  most  of  the  geologic  map- 
pmg  has  only  been  reconnaissance  and  was  not  performed  with 
any  special  attempt  to  evaluate  recency  of  faulting.  (On  the  other 
hand,  one  would  expect  that  any  truly  significant,  extensive 
Quaternary  faulting  would  have  been  recognized,  especially  in 
this  desert  terrane  where  faults  are  so  well-exposed  and  geo- 
morphic  features  endure  for  a  long  period  of  time.) 

Another  apparent  seismically  quiet  area  encompasses  the 
greater  part  of  the  Sierra  Nevada,  except  for  the  southernmost 
part  at  the  Tehachapi  Mountians,  and  to  a  much  lesser  degree, 
the  northernmost  part  in  theOrovillearea(Plates2Cand2D).Only 
a  very  few  magnitude  4  to  4.9  events  occur  in  the  larger  central 
part  of  the  Sierra  Nevada  block.  To  the  south,  the  White  Wolf- 
Walker  Pass  seismic  lineament  (and  perhaps  the  Kern  Canyon 


fault)  form  confining  boundaries  to  seismic  activity,  with  much 
more  activity  to  the  east  than  to  the  west.  West  of  the  Sierra,  the 
Great  Valley  is  also  quiet  like  the  Sierra. 

Few  seismic  events  have  been  plotted  in  the  northeastern  part 
of  the  state,  but  this  apparent  lack  of  historic  epicenters  may  be 
deceptive  because  this  sparsely  settled  area  is  remote  from  any 
seismic  network.  Three  major  faults  with  large  displacements 
must  have  had  considerable  Quaternary  activity — the  Surprise 
Valley,  Honey  Lake,  and  Likely  faults.  Hence,  it  may  be  delusive 
to  conclude  that  the  recent  history  of  sparse  seismic  activity  is 
an  indication  of  an  aseismic  area. 

The  western  tip  of  the  Mojave  wedge,  bounded  by  the  Garlock 
and  San  Andreas  faults,  is  anomalously  free  of  seismic  events  of 
magnitude  4  and  greater.  Only  a  few  Quaternary  faults  have  been 
mapped  in  this  area.  This  may  be  deceptive  because  faults  could 
easily  be  concealed  beneath  the  vast  blanket  of  alluvium  in  An- 
telope Valley. 

From  the  foregoing,  it  can  be  seen  that  certain  major  bounda- 
ries of  seismic  activity  appear  in  the  state,  such  as  along  the 
Sierran  front,  the  Mendocino  fault  zone,  and  the  White  Wolf- 
Walker  Pass  trend.  These  correspond  to  certain  boundaries  of 
the  structural  provinces  described  in  the  section  on  fault  pat- 
terns. In  addition  to  these  there  are  other  seismic  boundaries. 
For  example,  at  the  boundary  between  the  Transverse  Ranges 
and  the  Peninsular  Ranges — especially  where  the  Newport-In- 
glewood and  the  San  Jacinto  faults  approach  the  transverse 
Santa  Monica  and  Cucamonga  faults — there  appears  to  be  a 
concentration  of  seismic  activity.  Another  example  is  the  appar- 
ent boundary  between  the  area  of  extensive  seismicity  in  the 
Coast  Ranges  province  and  the  area  of  extremely  low  seismi- 
city in  the  Great  Valley  province. 

In  a  similar  fashion,  several  of  the  sub-block  structural  bound- 
aries described  earlier,  are  well  marked  by  seismic  activity.  Espe- 
cially good  examples  are  the  sub-blocks  marked  by  the  San 
Jacinto,  Elsinore,  Palos  Verdes,  Calaveras,  and  Hayward  faults. 

The  coincidence  of  so  many  of  these  seismic  boundaries  and 
trends,  with  the  structural  provinces  circumscribed  by  fault 
trends,  suggests  a  strong  relationship.  This  relationship  supports 
the  idea  of  the  crust  being  divided  into  structural  blocks  and 
sub-blocks  which  interact  along  their  boundaries  giving  rise  to 
the  major  earthquakes.  The  vast  number  of  small,  apparently 
random  earthquakes  in  the  state  may  be  explained  as  events 
occurring  within  these  structural  blocks  and  sub-blocks  as  a 
response  to  minor  crustal  adjustments  within  the  blocks  them- 
selves. 

CAUTIONS  IN  USE  OF  FAULT  MAP  OF 
CALIFORNIA  FOR  LAND-USE  PLANNING 

The  Fault  Map  of  California  is  a  useful  tool  for  considering 
fault  hazards  in  various  parts  of  the  state.  However,  it  cannot  be 
overstressed  that  the  nature  and  scale  of  the  map  pose  severe 
limitations.  First  of  all,  more  faults  exist  than  are  portrayed — the 
limitations  of  the  map  scale  alone  (in  which  .32  cm  [one-eighth 
inch]  on  the  map  represents  about  2.4  km  [1.5  miles]  on  the 
ground)  restricts  what  can  be  shown  at  1:750,(X)0  scale.  Second- 
ly, some  faults  are  hidden  beneath  alluvium  and  other  surficial 
deposits,  or  concealed  by  water;  or  they  simply  have  not  been 
recognized  because  of  insufficient  geologic  investigations.  Also, 
it  is  important  to  remember  that  the  map  is  a  product  of  numer- 
ous sources,  some  of  which  are  more  detailed  than  others,  and 
that  some  observations  were  made  by  geologists  whose  objectives 
and  purposes  may  not  have  included  the  evaluation  of  faults. 
Therefore,  the  degree  of  validity  for  the  faults  shown  on  the 
Fault  Map  varies  from  area  to  area.  This  is  not  only  true  for  the 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


43 


existence  or  extent  of  some  faults,  but  sometimes  in  regard  to  age 
designations  of  fault  displacement  as  well.  Thirdly,  not  all  the 
faults  shown  in  black  should  be  assumed  to  be  of  pre-Quatemary 
age.  Unfortunately  this  assumption  has  been  made  by  some,  even 
though  the  explanation  on  the  map  states  that  faults  shown  in 
black  may  also  signify  a  "fault  without  recognized  Quaternary 
displacement."  The  map  explanation  also  has  this  to  say  about 
faults  shown  in  black: 

Faults  shown  in  this  category  should  not  necessarily  be 
considered  "dead."  Evidence  for  recency  of  movement 
may  not  have  been  observed,  or  it  may  be  lacking  because 
the  fault  may  not  be  in  contact  with  Quaternary  deposits. 
In  many  cases,  the  evidence  may  have  been  destroyed  by 
erosion,  covered  by  vegetation,  or  by  works  of  man. 

Above  all,  the  State  Fault  Map  should  not  be  used  to  replace 
detailed  site  investigations  for  specific  undertakings.  For  engi- 
neering purposes,  faults  at  specific  sites  should  be  individually 
examined  by  detailed  surface  examination.  Trenching,  drill 
holes,  and  geophysical  techniques  may  be  helpful. 

Certain  precautions  must  be  specifically  mentioned  concern- 
ing the  offshore  areas.  The  offshore  submarine  faults  shown  have 
not  been  directly  observed  but  rather  interpreted  from  various 
remote-controlled  devices.  In  addition,  because  of  the  difficulties 
in  ship  positioning,  offshore  faults  may  not  be  as  precisely  locat- 
ed as  those  on  land.  Factors  such  as  the  type  of  geophysical 
equipment  used,  the  depth  to  the  sea  floor,  and  the  character  of 
the  rocks  and  sediments  below  the  sea  floor  afTect  the  quality  of 
the  records  obtained. 

This  map  should  therefore  be  used  only  as  an  initial  guide,  or 
as  a  first  approximation,  or  for  regional  fault  considerations. 
Before  site-specific  decisions  are  made,  more  information  and 
maps  on  a  larger  scale  should  be  consulted.  The  Fault  Map  of 
California,  by  virtue  of  the  area  covered — an  entire  state,  and  a 
very  large  and  geologically  very  complex  one  at  that — must  be 
supplemented  with  additional  data.  Hopefully  this  map  and  this 
Bulletin  (especially  the  Index  to  the  Source  Data,  Appendix  D) 
will  be  useful  as  an  introduction  to  the  pertinent  geologic  litera- 
ture and  information  on  faults  that  were  known  at  the  time  of 
the  compilation.  These  references  should  be  considered  an  inte- 
gral part  in  the  understanding  and  use  of  the  Fault  Map  of 
CaUfomia,  for  by  referring  to  the  documentation  the  reader  can 
evaluate  the  interpretation  given,  and  may  possibly  come  to  a 
different  conclusion,  especially  if  subsequent  data  have  been  gen- 
erated. 

This  Fault  Map  of  California  should  not  be  confused  with  the 
"Special  Studies  Zones  Maps"  developed  as  a  result  of  the  Al- 
quist-Priolo  Special  Studies  Zones  Act  of  1972  amended  (Hart 
1980).  The  Special  Studies  Zones  Maps,  at  a  scale  of  1:24,000, 
were  conceived  at  a  different  time  and  for  a  different  purpose, 
and  may  not  always  agree  in  detail  with  the  Fault  Map  of  Cali- 
fornia. The  Fault  Map  of  California,  together  with  the  Geologic 
Map  of  California  were  developed  over  nearly  a  nine-year  period 
largely  preceding  the  Special  Studies  Zones  Maps.  It  should  be 
clearly  understood  that  no  desire  or  intent  is  implied  in  the  Fault 
Map  of  California  to  either  zone  active  faults  or  to  predict  where 
earthquakes,  with  or  without  ground  rupture,  might  occur. 

No  attempt  is  made  in  this  volume  to  describe  the  methods 
geologists  use  in  evaluating  fault  and/or  earthquake  hazards. 
Publications  on  the  subject  abound  and  their  numbers  continue 
to  increase.  The  following  partial  list  is  submitted  as  an  introduc- 
tory guide: 

Bonilla,  M.G.,  1970,  Surface  faulting  and  related  effects,  in 
R.L.  Wiegel,  editor.  Earthquake  engineering:  Prentice- 
Hall.  N.J..  p.  47-74. 


Borcherdt,  R.D.,  editor.  Studies  for  seismic  zonation  of  the 
San  Francisco  Bay  region:  U.S.  Geological  Survey  Profes- 
sional Paper  941 -A,  102  p. 

Cluff,  L.S.,  Slemmons,  D.B.,  and  Waggoner,  E.B.,  1970, 
Active  fault  zone  hazards  and  related  problems  of  siting 
works  of  man:  Proceedings,  Fourth  Symposium  on  Earth- 
quake Engineering,  University  of  Roorkee,  India,  p.  401- 
410. 

Grading  Codes  Advisory  Board  and  Building  Code  Com- 
mittee, 1973,  Geology  and  earthquake  hazards,  planner's 
guide  to  the  Seismic  Safety  Element:  Association  of  Engi- 
neering Geologists  (Southern  California  Section),  44  p. 

Hart,  E.W.,  1980,  Fault  hazard  zones  in  California:  Califor- 
nia Division  of  Mines  and  Geology  Special  Publication  42 
(Revised),  25  p. 

Lung,  R.,  and  Proctor,  R.,  editors,  1966,  Engineering  geol- 
ogy in  southern  California:  Association  of  Engineering 
Geologists  (Los  Angeles  Section),  389  p. 

Nichols,  D.R.,  and  Buchanan-Banks,  J.M.,  1974,  Seismic 
hazards  and  land-use  planning:  U.S.  Geological  Survey 
Circular  690,  33  p. 

Sherard,  J.L.,  Cluff,  L.S.,  and  Allen,  C.R.,  1974,  Potentially 
active  faults  in  dam  foundations:  Geotechnique  24,  no.  3, 
p.  367-428. 

Slemmons,  D.B.,  1977,  State-of-the-art  for  assessing  earth- 
quake hazards  in  the  United  States,  Report  6,  Faults  and 
earthquake  magnitudes:  U.S.  Army  Engineer  Waterways 
Experiment  Station  Miscellaneous  Paper  S-77-8,  129  p., 
and  Appendix,  37  p. 

Ziony,  J. I.,  Wentworth,  CM.,  Buchanan-Banks,  J.M.,  and 
Wagner,  H.C.,  1974,  Preliminary  map  showing  recency 
of  faulting  in  coastal  southern  California;  U.S.  Geologi  - 
cal  Survey  Map  MF-585,  with  8  p.  text. 


DEPICTION  OF  VOLCANOES 
Distribution  And  Age 

In  addition  to  the  faults,  some  565  volcanoes  are  shown  on  the 
Fault  Map  of  California.  These  consist  mostly  of  cinder  cones, 
although  volcanic  domes  and  plugs,  broad  shield  volcanoes,  and 
a  few  strato- volcanoes  (composite  cones)  are  included.  These 
volcanic  centers  are  associated  with  the  vast  outpourings  of  rela- 
tively young  lava  and  pyroclastic  rocks  depicted  on  the  Geologic 
Map  of  California  (1977).  The  volcanoes  shown  are  almost 
entirely  of  Quaternary  age.  Although  volcanism  has  been  very 
active  throughout  most  of  California's  geologic  history,  no  at- 
tempt has  been  made  to  locate  the  older  volcanoes  because  they 
were  mostly  ephemeral  structures  destroyed  during  the  course  of 
geologic  time  by  erosion. 

Of  the  volcanoes  shown  on  the  map,  five  were  the  centers  of 
eruption  in  recent  years  (Table  6) .  Many  other  volcanic  centers 
are  probably  of  Holocene  age  (less  than  about  11,000  years). 
These  centers  are  located  in  such  areas  as  Medicine  Lake  High- 
lands-Lava Beds  National  Monument  (Siskiyou  and  Modoc 
counties),  Inyo-Mono  Craters  (Mono  County),  Clear  Lake  area 


44 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


(Lake  County),  and  Amboy-Pisgah  Craters  (San  Bernardino 
County).  Most  of  the  volcanoes  shown  on  the  map  are  older  than 
Holocene  but  less  than  two  million  years  old.  A  few  volcanoes 
shown  on  Geologic  Data  Map  No.  1  are  of  Pliocene  age  (two  to 
five  million  years  old). 

Table  6.      Observed  volcanic  events  in  California  (modified 
after  C.W.  Chesterman,   1971). 


1951  Violent  eruption  of  mud-volcanoes  and  hot  water  dis- 

charge at  Lake  City.  Modoc  County. 

1914-17    Eruption  of  Mt.  Lassen,  lava  flows,  ash  falls,  mud  flows, 
and  nu6es  ardentes. 

1890  Eruptions  in  Mono  Lake,  including  emission  of  steam, 

sulfurous  fumes,  boiling  water,  and  hot  mud. 


1857 


Ash  eruption  from  either  Mt.  Lassen  or  Mt.  Shasta. 


1851-62    Eruption  of  Cinder  Cone  and  associated  lava  flows. 
east  of  Lassen  Peak. 

1786  Eruption  of  steam  and  ash  from  either  Mt.  Lassen  or 

Mt.  Shasta  (observation  of  La  Perouse  while  sailing 
along  the  California  coast). 


Relation  of  Volcanoes  to  Faults 

The  relation  of  volcanic  centers  in  California  to  faults  remains 
a  subject  of  controversy,  although  there  are  certainly  several 
places  in  the  state  where  there  is  clear  evidence  or  strong  sugges- 
tion of  such  a  relationship.  For  example,  Howel  Williams  (1934, 
p.  232)  pointed  out  that  the  alignment  of  five  plug  domes,  two 
cinder  cones,  and  one  lava  cone  suggests  a  through-going  frac- 
ture passing  across  the  summit  of  Mount  Shasta  even  though  no 
surface  displacements  are  to  be  seen  along  this  trend.  Similar 
alignments  can  be  seen  on  the  maps  by  Gordon  Macdonald  in 
the  Lassen  Peak  area.  The  close  alignment  of  nine  cinder  cones 
east  of  Crater  Peak  (Manzanita  Lake  quadrangle),  about  19  km 
(12  miles)  north  of  Lassen  Peak,  is  strongly  suggestive  of  fault 
or  fissure  control,  as  is  the  alignment  of  at  least  19  cinder  cones 
in  the  eastern  part  of  Lassen  National  Park,  south-easterly  from 
Poison  Lake,  on  the  Harvey  Mountain  and  Prospect  Peak  quad- 
rangles (Macdonald,  1963,  1964,  1965). 

The  arcuate  alignment  of  more  than  1 5  volcanic  eruptive  cen- 
ters south  of  Mono  Lake,  including  the  rhyolite  domes  of  Mono 
Craters,  is  a  classic  example  of  fault-controlled  volcanoes  (Fig- 
ure 6).  Russell  (1889)  was  probably  the  first  to  conclude  that 
the  Mono  Craters  were  probably  localized  along  faults  (related 
to  the  faults  along  the  east  scarp  of  the  Sierra  Nevada).  Mayo 
and  others  (1936)  described  the  structures  in  the  rhyolite  domes 
south  of  the  Mono  Craters  and  concluded  that  they  are  deter- 
mined by  faults  in  turn  controlled  by  northwest-striking  joint 
sets  in  the  bedrock.  Kistler  (1966)  proposed  that  the  arcuate 
traces  of  faults  are  not  related  to  joint  sets  but  to  a  zone  of 
weakness  thought  to  be  related  to  the  early  cooling  history  along 
the  border  of  a  quartz  monzonitc  pluton.  In  any  event,  the 
existence  of  a  fault  control  beneath  the  line  of  Mono  Craters  was, 
in  fact,  confirmed  dunng  the  construction  of  the  Los  Angeles 
Water  District  tunnel  (Putnam.  1949,  p.  1299). 

Another  clear  example  of  fault-controlled  volcanoes  is  the 
Quaternary  (possibly  1872)  fault  scarp  that  trends  between  the 
volcanic  cones  of  Red  Mountain  and  Crater  Mountain,  in  Owens 
Valley  south  of  Big  Pine  (Allen.  1965.  p.  761;  and  Mayo.  1941. 


p.  1065).  In  fact,  Mayo  described  the  fault  boundary  between  the 
Sierra  Nevada  and  the  bedded  sediments  to  the  east  as  a  deeply 
penetrating  zone  of  weakness  that  opened  many  channels  for  the 
extrusion  of  lava  and  the  location  of  volcanoes  (Mayo,  1941,  p. 
1064-1069). 

According  to  Koenigand  others  (1972,  p.  1,4),  the  extrusions 
in  the  Coso  geothermal  area,  Inyo  County,  consisting  of  a  mix- 
ture of  explosion  breccia  rings,  perlite  domes,  and  obsidian  sills, 
are  fracture-controlled.  Inspection  of  the  geologic  map  of  the 
Haiwee  Reservoir  quadrangle  (Stinson,  1977)  shows  conspicu- 
ous north  and  northwest  alignments  of  volcanic  centers.  These 
may  be  fault  controlled,  perhaps  by  a  buried  north-trending  fault 
zone  and  a  northwest-trending  fault  zone.  More  recent  geologic, 
geophysical,  and  geochemical  studies  in  the  Coso  area  suggest 
that  the  youngest  volcanic  rocks,  the  rhyolitic  dome  field,  and 
the  associated  fumaroles  lie  at  the  center  of  a  ring-fault  structure 
superimposed  on  regional  fault  patterns  and  overlying  a  young 
magma  chamber  (Duffield,  1975;  and  ERDA  77-74,  p.  65). 

Allen  and  others  (1965,  p.  761)  have  shown  that  Cerro  Prieto, 
a  Quaternary  cone,  35  km  south  of  the  Mexican  border,  lies 
squarely  athwart  the  extended  trace  of  the  Quaternary  San  Ja- 
cinto fault. 

In  San  Luis  Obispo  County,  14  intrusive  volcanic  plugs  are 
aligned  over  a  distance  of  approximately  32  km  (20  miles)  (see 
Figure  13)  through  the  town  of  San  Luis  Obispo  to  Morro  Rock 
(and  offshore,  according  to  H.C.  Wagner,  1974).  These  Tertiary 
plugs,  although  much  older  than  the  Quaternary  volcanoes 
shown  on  the  Fault  Map  of  California,  appear  to  be  another 
example  of  emplacement  of  volcanic  centers  along  a  zone  of 
weakness  that  in  all  probability  is  a  fault  even  though  a  fault 
trace  has  not  been  observed  in  the  field. 


EXPLANATION 

[H 

Ouolcrnarir 
dcpoiiti 

m 

T«rl.O(y 
maiinc  rockt 

Crdoctoui 
maont  lockk 

FroncitCOn 
CompUi 

Cr«tae«ou» 
gianilic  rochi 


Tvilisri 
•Cconic  plug 

» 

T«ri>o>y  volconic 
plug  Itubntorint) 


Figure  13.     Alignment  of  Tertiary  volcanic  plugs  near  San  Luis  Obispo  along 
o  line  of  weakness  presumed  to  be  an  ancient  fault. 

Volcanic  Hazards 

Volcanic  eruptions  have  commonly  occurred  throughout  Cali- 
fornia's long  geologic  history,  and  numerous  eruptions  have  oc- 
curred in  relatively  recent  geologic  time,  as  indicated  by  the  large 
number  of  volcanoes  depicted  on  the  Fault  Map  of  California. 
Volcanism  has  occurred  in  California  approximately  65  years  ago 
with  the  violent  eruption  of  Lassen.  It  would  therefore  seem 
reasonable  to  expect  other  eruptions  in  the  state,  although  exact- 
ly when  or  where  is  uncertain.  The  most  probable  centers  of 
future  volcanic  eruptions  are  in  areas  where  past  eruptions  have 
occurred  and  particularly  at  large  central-vent  volcanoes  (Mil- 
hneaux.  1976). 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


45 


The  Urban  Geology  Master  Plan  for  California  (Alfors  and 
others,  1973)  estimates  that  losses  due  to  future  volcanic  erup- 
tions could  amount  to  $50  million  between  1970  and  the  year 
2000.  The  report  concludes  that  major  urban  areas  of  the  state 
are  relatively  safe  from  the  threat  of  volcanic  eruptions. 


DEPICTION  OF  THERMAL  SPRINGS 
AND  WELLS 

Besides  faults  and  volcanoes,  584  thermal  springs  and  wells 
are  also  plotted  on  the  Fault  Map  of  California.  Separately  iden- 
tified are  the  locations  of  high  temperature  mud  volcanoes  and 
mud  pots  at  Wister  (Imperial  County),  Lake  City  (Modoc 
County),  and  the  unusually  prolific  carbon  dioxide  springs  and 
wells  at  Niland  (Imperial  County)  and  Hopland  (Mendocino 
County).  Many  of  the  hot  springs  are  clearly  associated  with 
known  faults  or  volcanic  rocks.  Where  a  hot  spring  is  not  shown 
associated  with  a  fault,  it  may  indicate  that  the  area  has  not  been 
mapped  in  sufficient  detail. 

The  location  of  hot  springs  and  wells  serves  as  an  approximate 
guide  to  areas  of  anomalously  high  temperatures  present  today 
in  the  crustal  rocks  of  California.  This,  of  course,  is  pertinent  in 
the  exploration  of  geothermal  power  sources.  In  volcanic  areas, 
the  location  of  hot  springs  may  indicate  either  a  dying  phase  of 
volcanism  or  a  precursor  of  volcanic  activity. 

Information  concerning  temperatures,  more  specific  location 
data,  well  depths,  date  drilled,  and  pertinent  references  is  con- 
tained in  Appendix  B. 


Temperature 

Following  the  convention  established  by  G.A.  Waring's  re- 
jxjrts  (1915  and  1965),  which  were  the  principal  sources  used 
when  this  present  compilation  was  started,  the  writer  considered 
as  thermal  only  those  springs  that  are  more  than  15°F  (8.3°C) 
above  the  mean  annual  temperature  of  the  air  at  their  localities. 
In  the  case  of  drilled  wells,  a  normal  thermal  gradient  of  about 
VF  increase  for  each  100  feet  of  depth  (2°C  for  each  100  meters) 
was  taken  into  consideration  when  determining  whether  the  well 
should  be  classified  as  thermal. 

The  water  from  thermal  springs  may  be  meteoric — that  is, 
surface  water  that  has  percolated  downward,  been  heated,  and 
then  ascended  to  the  surface.  Or,  thermal  water  may  be  juvenile 
—that  is,  a  product  from  the  magma;  water  which  has  reached 
the  surface  for  the  first  time.  Thermal  spring  waters  also  may  be 
a  mixture  of  meteoric  and  juvenile  water.  Methods  of  distin- 
guishing between  juvenile  and  meteoric  waters  by  major  and 
minor  element  chemistry,  isotope  ratios,  and  other  means  are 
described  by  White  (1969). 

The  abnormally  high  temperature  of  hot  springs  and  wells 
may  fluctuate  or  even  normalize,  and  some  springs  and  wells 
may  "dry  up"  or  cease  to  flow.  One  of  the  factors  commonly 
accounting  for  these  phenomena  in  California  is  the  occurrence 
of  earthquakes.  Another  factor  commonly  affecting  springs  is 
the  precipitation  of  calcium  carbonate,  which  causes  clogging, 
resulting  in  reduction  of  flow  and  ultimately  cessation. 

Springs  close  to  boiling-point  temperatures  are  found  in  many 
localities  in  the  state.  Because  the  boiling  point  decreases  with 
an  increase  in  elevation,  the  boiling  temperature  of  springs  in 
California  ranges  from  212°F  (100°C)  at  sea  level  to  about  185°F 
(85°C)  at  14,250  feet  (4377  m).  Table  7  summanzes  the  loca- 
tions of  springs  near  the  boiling  point  in  California. 


Mode  of  Occurrence  Of  Hot  Springs 

Thermal  springs  in  California  are  probably  associated  with  or 
controlled  by  one  or  more  of  the  following  geologic  conditions: 

(1)  areas  of  volcanoes  of  geologically  recent  activity 

(2)  frictionally  heated  rocks  associated  with  faults 

(3)  intensely  deformed  mountains 

(4)  jointed  or  faulted  batholithic  rocks 

1 .  In  some  areas  of  volcanic  rocks,  especially  in  areas  of  recent- 
ly active  volcanism,  magma  or  solidified  magma,  probably  lies 
below  the  surface  that  has  not  cooled  to  normal  temperatures, 
and  water  coming  near  it  will  be  heated.  In  a  few  places — at  The 
Geysers  area  of  Sonoma  County,  for  example — it  is  believed  that 
heat  from  magma  at  depth  has  been  transmitted  to  the  overlying 
rock.  Meteoric  water  penetrating  near  the  hot  materials  is  thus 
heated.  Faults  and  fractures  may  serve  as  conduits  bringing  the 
hot  water  to  the  surface. 

2.  Rocks  along  fault  zones  are  heated  considerably  by  the  great 
pressure  and  friction  that  are  produced  by  extensive  masses  of 
rock  moving  past  one  another.  This  is  evidenced  by  the  presence 
of  fused  mylonite  or  crushed  rock  along  certain  fault  zones 
(Wallace,  1976).  In  an  analysis  of  faulting,  McKenzie  and 
Brune  (1972)  have  shown  that  a  temperature  of  1000°C  can  be 
obtained  by  frictional  heating  along  a  fault,  with  actual  melting 
taking  place  along  the  fault  plane.  When  water  comes  in  contact 
with  a  fault  zone,  fault  gouge  can  act  as  a  barrier  to  lateral 
migration,  and  the  crushed  zone  adjacent  to  the  fault  gouge  can 
serve  as  a  conduit  for  water  to  reach  the  surface.  Thus,  if  water 
passes  upward  near  recently  active  faults,  the  water  can  take  up 
heat  by  contact  with  the  frictionally  heated  rocks. 

3.  It  can  be  reasonably  assumed  that  accompanying  intense 
deformation  of  crustal  rocks  by  folding  and  faulting,  a  considera- 
ble amount  of  thermal  energy  is  generated.  Furthermore,  a  sig- 
nificant portion  of  the  thermal  energy  is  expected  to  remain 
stored  over  a  certain  interval  of  geologic  time  (Chaterji  and 
Guha,  1968).  For  example,  only  comparatively  recent  (Tertiary 
or  post-Tertiary)  deformation  might  be  expected  to  account  for 
the  heat-flow  of  certain  thermal  springs.  A  good  example  of  this 
may  be  a  comparison  of  the  abundant  warm  springs  in  the  Late 
Tertiary-Quaternary  highly  deformed  Coast  Ranges  with  the 
almost  total  absence  of  thermal  springs  in  the  Klamath  Moun- 
tains— the  intense  deformation  of  the  Klamaths  having  largely 
taken  place  in  pre-Tertiary  time. 

4.  Deep  joints  or  faults  in  batholithic  rocks,  like  those  in  the 
Sierra  Nevada,  occasionally  give  rise  to  moderately  warm 
springs.  Meteoric  waters  collected  in  such  cracks  may  be  heated 
by  the  disintegration  of  radioactive  elements  in  the  granitic  rocks 
(Kiersch,  1964,  p.  43). 


Distribution  Of  Hot  Springs 

Hot  springs  in  California  have  a  wide  geographic  distribution. 
Because  the  state  is  readily  divisible  into  1 1  geomorphic  prov- 
inces, each  reflecting  fundamental  differences  in  geology  (Figure 
14),  Cahfomia's  thermal  springs  will  be  discussed  in  relation  to 
these  provinces.  Although  no  consistent  or  clear  relation  of  the 


46 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Table  7.      Springs  near  boiling  point  temperature. 


STAU   MAP 
SHEET       . 

SPRING 

COUNTY 

ELEV 

TEMP 

CF) 

ROCK  TYPE 

STRUCTURE 

NOTES 

LOCATION  NO 

A.!^r« 

"Mud  volcanoes '  neat 

Lake  C-ty 

Modoc 

4480 

120-207 

In  alluvium  very  dose  to  Late 
Tertiary  volcanic  rocks. 

Surprise  Valley  fault  zone 

A    maior    normal    fault    in    California, 
Fault    probably  serves  as  a  conduit  for 
heat  below,  as  well  as  con  inbutmg 
frictionai  heal. 

\7 

Ho(  Spnngs  near 
Cedarviiie 

Modoc 

4b00 

200 

tn  alluvium  not  far  from  Late 
Tertiary  volcamc  roclcs. 

Surprise  Valley  fault 
trough. 

Ditto 

U 

Benmac  Hot  Spfings  and 
Surpf.se  Valtev 
Hot  Springs 

Modoc 

4500 

4500 

205-207 
209 

In  alluvium  not  far  from  Late 
Tertiary  volcanic  f Celts. 

Surprise  Valley  fault 
trough. 

Ditto 

Kellev  Hot  Springs 

Modoc 

4360 

204 

In  close  proximity  to 
Pleistocene  volcanic  rocks 

On  fault 

Fault  probably  serving  as  heat  conduit 
from  votcan.cs  below 

DMih  Valley 

Devib  Kitchen  Fumaroie 

Inyo 

4290 

180  to 
twiling 

In  Hotocene  volcanic 

rocks 

Fractured  volcamc 
caldera 

Ditto 

7 

a 

COSO  Hoi  Springs 

Inyo 

3600 

140  to 
boiling 

In  alluvium,  not  (ar  (rom 
Ouaternarv  volcamcs 

On  Quaternary  fault 

D.I10 

Los  Angeles 

Sesoe  Hoi  Springs 

Ventura 

2850 

I9M94 

In  Pine  Mm.  fault  zone. 
highly  folded  strata 

7 

Ma'.posa 

Paoha  Is  springs  and 
Steam  vents 

Mono 

6400 

203 

In  lake  sediments  very  dose 
to  Pleistocene  volcanic  rocks 

I 

12 

C«sa  Dtabk)  Hot  Springs 

Mono 

7290 

115-194 

Pleistocene  basalt. 

Volcanic  caldera 

Fault  acting  as  conduit  from  heat  be- 
low 

IB 

HOI  Creek  Geysers 
(springs) 

Mono 

7040 

194-203 

Pliocene  rhyolite  (not  far 
(rom  Pleistocene  basalt) 

D'T!0 

D'tro 

Senofi  Sea 

Mud  pots 

Irnpenal 

.'ij 

100  to 
boi'ing 

Alluviurr>-(ake  beds.  Holocene 
volcamcs  tn  vicinity- 

On  or  near  concealed 
San  Andreas  fault 
extension 

Heat  from  mantle  below  Ihm  crust? 

*«5 

San  Bernardino 

Waterman  Hot  Springs 

San  Bernardino 

wso 

123-210 

Fractured  granitic  and 
gneissic  rocks 

On  branch  of  San 
Andreas  fault 

b 

0 

Arrowhead  Hot  Springs 

San  Bernardino 

2000 

110-202 

Ditto 

On  branch  ol  San  Andreas 

fault 

Santa  Hosa 

The  Geysefs 

Sonoma 

1600  2 

140  to 

botlmg 

Jurassic(?)  Franciscan  rocks 
Quaternary  volcamc  in    v.cr  :> 

On  or  dose  to  faults 

faults  transmitting  heat  from  shsiiow 
magma  to  Overlying  rocks- 

13 

Waike'  Lake 

Faies  Hot  Sprtng^ 

Alpine 

7400 

176 

Pliocence  volcamcs  over- 
lain by  glacial  deposits 

Heat  of  the  water  probable  derived  from 
the  nearby  lava—  Waring  (1915)  p   133 

3 

Weed 

Hoi  Springs  or 
Mount  Shasta 

Siskiyou 

14,000 

184 

Pleistocene  and  Holocene 
volcanic  rocks 

Strato  volcano 

■  Possibly  (resh  magma   withm  the  cone* 
— H   Williams  (1934)    p   228 

' 

Suianville 

''.Vf-.'AO'ydi 

Tophet  Hot  Springs 
(Lassen  area) 

Shasta 

/ooo 

175  to 

boiling 

Pleistocene  volcanic  rocks;  not 
far  from  Holocene  volcamcs. 

Recently  active  volcano 

Part  of  the  water  from  the  springs  iS 
probably   of  juvenile  origin,  derived 
from  an  under  lying  magn^a  or  batholith 

4 

s 

7 

BufTtpas  Hot  Springs 
Growler  Hot  Springs 

Shasta 

Tehama 

8160 
5120 

boiling 
203  + 

Pleistocene  volcamc  rocks. 

not  far  from  Holocene  volcanics 

Pleistocene  volcamc  rocks 

Ditto 

Ditto 
Ditto 

11 

Boiling  Spririg  Tartarus 
Lake 

Plumas 

5920 

170-190 

Pleistocene  volcamc  rocks 

On  small  fault. 

Fault  probably  serving 

as  heat  conduit  from  volcamcs  botow 

12 

Plumas 

5920 

120-205 

Pleistocene  volcanic  rocks 

On  small  fault. 

Ditto 

IB 

Wendel  Hot  Springs 

Lassen 

4038 

206 

Alluvial  deposits;  close  to 
Pdo-Pieistocene  volcamc  rocks 

On  Litchfield  fault. 

Ditto 

Amedee  Hoi  Spnngi 

Lassen 

4000 

178-204 

Alluvial  deposits,  dose  to 
PlioPfoislocene  volcamc  rocks 

On  Amedee  fault 

Ditto 

•S«  imp  ihceu  in  Appendix  D  and  ublualcd  dau  in  Appendix  B 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


47 


hot  springs  to  the  four  previously  mentioned  geologic  modes  of 
occurrence  discussed  is  always  discemable,  where  these  condi- 
tions are  recognized,  they  will  be  briefly  described. 

The  Modoc  Plateau  in  northeastern  California  is  a  region  of 
extensive  Late  Tertiary  and  Quaternary  lava  flows  and  vol- 
canoes. Within  these  volcanic  rocks  are  hot  springs  that  probably 
derive  heat  from  the  same  source  as  the  lava  outpourings.  Al- 
though the  area  is  largely  mapped  only  in  a  reconnaissance  way, 
often  the  thermal  springs  appear  to  be  fault  controlled. 

Immediately  east  of  the  Modoc  Plateau  is  Surprise  Valley  in 
the  Basin  Ranges  province,  a  province  characterized  by  vol- 
canism  and  block  faulting.  Here,  five  boiling  springs  and  four 
thermal  wells  are  aligned  along  the  Surprise  Valley  fault,  a  major 
Quaternary  fault  with  vertical  movement  estimated  in  excess  of 
1650  m  (5500  feet)  (Gay,  1959)  and  associated  with  promi- 
nent gravity  and  magnetic  anomalies.  It  also  has  evidence  of  Late 
Quaternary  activity.  Several  other  springs  in  California's  Basin 
Ranges  province,  some  at  boiling  temperature,  occur  in  the 
Honey  Lake  volcanic  area.  The  springs  are  situated  along  the 
Quaternary  Amedee  and  Litchfield  faults  and,  farther  to  the 
south,  in  the  Coso Mountains,  on  faults  in  an  area  of  Quatenary 
volcanism. 

Two  of  California's  most  famous  volcanoes.  Mount  Shasta 
and  Lassen  Peak,  lie  in  the  southernmost  end  of  the  Cascade 
Range  province.  This  province  consists  of  a  chain  of  volcanoes 
extending  into  Oregon  and  Washington.  Mount  Shasta  and  Las- 
sen Peak,  both  active  in  historic  time,  are  the  sites  of  several  hot 
springs,  steam  vents,  and  fumaroles.  The  associated  hot  springs 
are  clearly  related  to  recent  volcanism  and  probably  to  faults. 

The  Sierra  Nevada  province  is  bounded  by  a  profound  fault 
on  the  east  side,  which  is  the  loci  of  several  hot  springs,  especially 
where  geologically  recent  volcanism  has  occurred,  such  as  at  the 
Mono  Lake,  Casa  Diablo,  and  Owens  Lake  areas.  The  south- 
central  part  of  the  Sierra  Nevada  batholith  is  also  the  site  of 
several  warm  springs.  Here  hot  water  issues  from  granitic  and 
metamorphic  rocks  far  removed  from  young,  volcanic  rocks. 
The  springs  appear  to  be  related  to  the  Kem  Canyon  fault  along 
which  they  lie.  As  suggested  earlier,  the  heat  may  be  derived 
from  the  disintegration  of  radioactive  elements  in  the  granitic 
rock.  The  Kem  Canyon  fault,  although  a  major  tectonic  feature, 
is  probably  not  active,  inasmuch  as  undisturbed  Pliocene  vol- 
canic rocks  are  known  to  lie  athwart  the  trace  of  the  fault. 

Hot  springs  in  the  northern  part  of  the  Coast  Ranges  province 
in  California  are  both  numerous  and  among  the  hottest  in  the 
state.  Most  of  them  are  associated  with  the  Clear  Lake  and 
Sonoma  volcanic  areas,  or  lie  in  the  intensely  faulted  and  de- 
formed Mayacmas  Mountains.  The  Clear  Lake  Volcanics  are 
late  Pliocene  to  Holocene  in  age  (Heam  and  others,  1975)  and 
the  older  Sonoma  Volcanics  are  Pliocene.  The  Mayacmas  Moun- 
tains lie  between  the  Clear  Lake  and  Sonoma  volcanic  areas. 
Here,  in  the  world-famous  area  of  The  Geysers,  is  the  first  (and 
at  present,  the  only)  commercially  developed  geothermal  power 
source  in  the  United  States.  The  Geysers  are  situated  in  meta- 
morphosed, sedimentary,  and  volcanic  Mesozoic  rocks  of  the 
Franciscan  Complex,  and  although  no  geologically  recent  vol- 
canic rocks  are  exposed,  the  area  is  marked  by  numerous  fuma- 
roles, steam  vents,  and  other  signs  of  active  volcanism.  The  area 


is  highly  faulted,  and  the  source  of  heat  is  probably  a  magma 
chamber  at  shallow  depth  (Chapman,  1957). 

Moderately  warm  springs  are  scattered  in  the  central  and 
southern  parts  of  the  Coast  Ranges  province  in  highly  folded  and 
faulted  Mesozoic  and  Tertiary  strata.  Likewise,  the  Transverse 
Ranges  is  a  highly  folded  and  faulted  province  marked  by  a 
number  of  thermal  springs,  including  the  near-boiling  Sespe  Hot 
Springs  in  the  Santa  Ynez  Mountains.  The  Sesi>e  Hot  Springs  are 
situated  within  the  Pine  Mountain  fault  zone.  In  the  eastern  part 
of  the  Transverse  Ranges,  in  the  San  Bernardino  Mountains,  are 
the  Arrowhead  Springs.  This  group  of  boiling  springs  is  also  on 
a  fault,  probably  a  splay  of  the  San  Andreas  fault. 

The  Peninsular  Ranges  province,  in  the  southwestern  part  of 
the  state,  has  a  number  of  warm  springs.  These  springs  he  close 
to  the  Elsinore  and  San  Jacinto  fault  zones.  The  thermal  springs 
in  the  Peninsular  Ranges  province,  the  central  and  southern 
Coast  Ranges,  and  the  Transverse  Ranges  are  all  outside  areas 
of  geologically  recent  volcanism  (although  containing  volcanic 
rocks  of  earlier  geologic  time).  These  provinces,  however,  are 
among  the  most  active  tectonically,  and  are  traversed  by  numer- 
ous major  faults.  These  provinces  are  also  intensely  folded  and, 
in  places,  as  for  example  the  western  Transverse  Ranges,  are  still 
undergoing  active  deformation  by  folding,  uplift,  and  faulting. 

The  Salton  Trough  is  essentially  a  graben  or  down-faulted 
block.  Numerous  mud  volcanoes  and  hot  springs  are  situated 
principally  along  or  near  the  active  San  Andreas  fault  zone  on 
the  east  side  of  the  graben.  For  example,  shallow  hot  water  wells 
occur  at  Desert  Hot  Springs,  a  hot  spring  is  found  at  Dos  Pal- 
mas,  and  numerous  mud  volcanoes  occur  at  the  southeastern  end 
of  the  Salton  Sea.  Also  in  this  fault  trough,  numerous  explora- 
tory wells  have  tapped  high  temperature  steam  and  brine  on 
some  of  the  largest  known  geothermal  anomalies  of  the  state. 
One  of  these  geothermal  anomalies,  at  Niland,  is  associated  with 
relatively  young  volcanic  rocks  which  are  dated  at  16,000  years 
(Muffler  and  White,  1969). Positive  gravity  and  magnetic  anom- 
alies suggest  the  presence  of  intrusive  bodies  at  shallow  depth. 

The  Mojave  Desert  province,  although  containing  both  exten- 
sive volcanic  rocks  of  recent  geologic  age  and  numerous  exten- 
sive Quaternary  faults,  is  nearly  devoid  of  thermal  springs.  This 
is  probably  attributable  to  the  dearth  of  water  rather  than  to  the 
lack  of  a  subterranean  heat  source. 

The  Klamath  Mountains  province  in  northwestern  California, 
with  abundant  water,  and  lying  in  an  intensely  deformed  terrain, 
has  only  one  known  abnormally  high  temperature  spring.  This 
may  be  due  to  the  lack  of  geologically  recent  volcanism  or  to  the 
great  geologic  antiquity  of  the  deformation,  in  which  case  any 
thermal  energy  generated  from  these  movements  would  proba- 
bly have  dissipated  during  the  long  period  of  conduction  and 
radiation.  Another  possibility  might  be  related  to  the  huge  abun- 
dance of  ground  water  (one  of  the  highest  rainfall  areas  of  the 
state)  that  is  available  to  mix  with  and  cool  to  normal  tempera- 
tures any  hot  water  that  rises  from  the  underlying  rocks. 

The  remaining  natural  province  of  the  state,  known  as  the 
Great  Valley,  is  essentially  a  gigantic  alluvial  plain  containing  a 
tremendous  thickness  of  sediments.  It  is  not  surprising  that  no 
thermal  springs  (or  thermal  wells)  occur  in  this  province,  for  it 
lacks  a  known  subterranean  heat  source. 


48 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


iO 


®\  ■: 


••••  • 


■*a 


\K 


©N®\  ® 


1.  BASIN  RANGES 

2.  MODOC  PLATEAU 
3. CASCADE  RANGE 

4.  KLAMATH  MOUNTAINS 

5.  COAST  RANGES 

6.  GREAT  VALLEY 

7.  SIERRA  NEVADA 

8.  TRANSVERSE  RANGES 

9.  MOJAVE  DESERT 

10.  PENINSULAR  RANGES 

11.  SALTON  TROUGH 


.....*^ 


\ 


V 


©  V 


© 


8^  ^8 
^ 


..•••.  *. 


.:r  ® 


Figur«  14      Relief  Map  of  Californio  ihowing  geomorphic  provinces. 


PART  II 
GEOLOGIC  MAP  OF  CALIFORNIA 


The  Man  with  the  Hammer 

A  wanderer — with  downcast  eyes  he  looks 
For  truth  'mid  ruins  and  the  dust  of  Time. 
The  strata  of  the  mountains  are  his  books 
Wherein  he  reads,  as  he  does  slowly  climb. 


— -A.C.  Lawson 

University  of  California  Chronicle 

October  1925 


GEOLOGIC  MAP  OF  CALIFORNIA 


INTRODUCTION 


More  than  90  years  have  passed  since  the  preparation  in  1891 
of  the  1:750,000  scale  Preliminary  Mineralogical  and  Geological 
Map  of  the  State  of  California.  The  1977  edition  of  the  Geologi- 
cal Map  of  California  is  the  latest  in  the  series  of  statewide 
geologic  maps  published  by  the  State,  and  represents  a  great  step 
forward  in  the  mapping  and  understanding  of  California's  geol- 
ogy. (See  Table  8  for  list  of  State  geologic  maps  of  California.). 


HISTORY  OF 
GEOLOGIC  MAPS  OF  CALIFORNIA 


fornia  State  Mining  Bureau.  Beginning  with  this  map,  the  re- 
sponsibility for  preparing  and  publishing  succeeding  editions  of 
relatively  large-scale  geologic  maps  of  California  has  remained 
with  the  State.  Only  eight  geologic  units  were  depicted  on  the 
1891  map;  however,  their  general  relations  are  better  shown  than 
on  all  the  previous  geologic  maps.  Special  emphasis  was  given  to 
mineral  resources.  Such  units  as  auriferous  gravel,  auriferous 
slate,  and  limestone  are  portrayed,  and  the  locations  of  known 
mineral  deposits  are  shown.  The  map  was  issued  by  the  State 
Mineralogist,  William  Ireland,  but  the  map  compiler  is  not  cred- 
ited on  the  map.  However,  the  10th  Annual  Report  of  the  State 
Mineralogist  (Ireland,  1890,  p.  21)  states  that  the  topographical 
and  other  work  on  the  Preliminary  Geological  and  Mineralogi- 
cal Map  was  "being  executed  by  Mr.  Julius  Henkenius,  who 
received  aid  in  the  geological  and  mineralogical  locatings  from 
the  Field  Assistants." 


The  First  Attempts 


Geologic  mapping  in  California  began  about  160  years  ago. 
The  first  geologic  mapping  in  the  state,  done  by  Lieutenant 
Edward  Belcher,  a  British  naval  officer,  was  a  remarkably  accu- 
rate geologic  map  of  the  Port  of  San  Francisco.  Although  Belch- 
er did  the  surveying  for  the  map  in  1826.  it  was  not  published 
until  1839.  This  map  and  other  early  geologic  maps  of  California 
are  described  and  illustrated  in  "State  Geologic  Maps  of  Califor- 
nia— a  Brief  History"  (Jennings,  1966). 

Landmarks  in  the  publication  of  early  geologic  maps  of  the 
entire  state  begin  with  the  hand-tinted  geologic  map  of  Califor- 
nia made  by  W.P.  Blake  in  1853  and  published  in  Volume  V  of 
the  War  Department's  "Report  of  Explorations  in  California  for 
Railroad  Routes"  (Blake,  1857).  Utilizing  nine  geologic  units, 
this  41  X  56  cm  (16  x  22  inch)  map  was  the  first  published 
geologic  map  that  specifically  and  exclusively  pertained  to  Cah- 
fomia.  This  map  was  followed  by  the  first  color-lithographed 
map  of  the  state,  made  in  1 867  and  published  four  years  later  in 
Paris  as  part  of  a  report  of  a  French  scientific  mission  to  Mexico 
and  the  "ancient  Mexican  possessions  of  the  north"  (Guillemin- 
Tarayre,  1871).  The  geology  is  portrayed  in  a  most  impressive 
manner  by  ten  geologic  units,  and  the  geologic  interpretation  is 
much  improved  over  Blake's  map. 

The  second  color-lithographed  geologic  map  of  California  was 
prepared  by  another  Frenchman,  Jules  Marcou  (1883),  and 
published  in  the  "Bulletin  of  the  Geological  Society  of  France." 
The  nine  geologic  units  shown  were  largely  based  on  Marcou's 
observations  while  working  with  the  Pacific  Railroad  Survey  in 
1854  and  the  Wheeler  Survey  West  of  the  100th  Meridian  in 
1875,  both  Federal  surveys.  The  map  was  accompanied  by  a 
report  on  the  geology  of  California. 

These  early,  page-size  geologic  maps  of  the  state  were  su- 
perseded in  1 89 1  by  the  first  relatively  large-sc£tle  statewide  geo- 
logic map. 

Preliminary  Mineralogical  and  Geological 
Map  of  the  State  of  California — 1891 

The  Prelimmary  Mineralogical  and  Geological  Map  of  the 
State  of  California,  at  a  scale  of  1:750,000  (12  miles  equals  one 
inch),  was  prepared  and  published  in  four  sections  by  the  Cali- 


Geological  Map  of  the 
State  of  California — 1916 

Twenty-five  years  after  the  1891  Preliminary  Mineralogical 
and  Geological  Map  of  the  State  of  California,  another  1:750,000 
scale  state  geologic  map  was  published  by  the  California  State 
Mining  Bureau.  This  map  was  prepared  by  J. P.  Smith,  Professor 
of  Paleontology  at  Stanford  University,  and  was  accompanied  by 
a  brief  bulletin  describing  the  geology  (Smith,  1916). 

The  map  legend  lists  21  geologic  units.  Although  Professor 
Smith's  bulletin  clearly  explains  that  certain  areas  of  California 
were  still  unmapped,  his  map,  unlike  the  earlier  1891  edition, 
shows  the  entire  area  of  the  state  covered  by  colors  representing 
geologic  units  with  delineated  contacts.  This,  unfortunately, 
leaves  the  map-user  without  any  clue  as  to  what  is  known  and 
what  has  merely  been  projected.  The  absence  of  geologic  faults 
on  this  map  is  also  somewhat  puzzling.  Although  faults  were  by 
this  time  widely  recognized  and  mapped — as,  for  example,  in  the 
atlas  accompanying  the  "State  Earthquake  Investigation  Com- 
mission" report  on  the  disasterous  1906  San  Francisco  earth- 
quake— not  even  the  San  Andreas  fault  is  shown  on  the  1916 
geologic  map  of  California. 

By  1916,  there  was  much  outstanding  geologic  mapping  to 
draw  upon.  U.S.  Geological  Survey  geologists  H.W.  Turner, 
Waldemar  Lindgren,  J.S.  Diller,  F.L.  Ransome,  G.H.  Eldridge, 
Ralph  Arnold,  Robert  Anderson,  R.W.  Pack,  and  H.W.  Fair- 
banks had  completed  a  number  of  geologic  folios  and  bulletins 
on  the  Sierra  Nevada  gold  belt  area,  the  Coast  Ranges,  and  the 
oil  regions  of  the  state.  In  addition,  many  significant  contribu- 
tions had  been  made  by  Professor  A.C.  Lawson  and  graduate 
students  at  the  University  of  California  and  by  Professor  J.C. 
Branner  and  his  students  at  Stanford  University. 

The  41-page  bulletin,  "The  Geologic  Formations  of  Califor- 
nia," which  accompanies  the  1916  Geological  Map  of  California, 
consists  of  the  following:  an  expanded  legend  for  the  reconnais- 
sance geologic  map;  a  description  of  the  geologic  record  of  Cali- 
fornia as  related  to  the  fluctuations  of  the  "Great  Basin  Sea"  and 
the  Pacific  Ocean;  a  description  of  the  "rock-forming  agencies 
of  California"  wherein  the  formation  of  igneous  rocks,  organic 
and  inorganic  sediments,  and  chemical  deposits  are  briefly  dis- 
cussed; a  listing  of  the  sources  of  data  for  the  geologic  map;  and, 
lastly,  a  listing  of  the  formations  included  in  each  geologic  unit 
shown  on  the  map. 


51 


52 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Table  8.      State  geologic  maps  of  California. 


DATE 
OF  MAP 

TITLE 

SCALE 

GEOLOGIC 
UNITS 

CONTOUR 
INTERVAL 

COMPILER 
(PUBLISHER) 

1857 

Geological  map  of  a  part  of  the 
State  of  California 

1  in.=38  mi 

9 

No  contours 

W.P   Blake 
(U.S.  Senate  Document) 

1867 

Carte  gfeologique  de  la  Haute 
California  et  de  la  Nevada 

1  in.  =  64  mi. 

10 

No  contours 

Guillemin-Tarayre 
(Pans.  France) 

1854- 
75 

Carte  g^ologique  de  la 
California 

1  in.  =  95  mi 

9 

No  contours 

J.  Marcou 

(Soc   Geol.  France 

Bull  ) 

1891 

Preliminary  mineralogical  and 

geological  map  of  tfie  State  of 

California. 

1  in.  =  12  mi. 
(1:750.(X)0) 

8 

No  contours 
(Shaded  relief) 

J.  Henkenius 
(State  fVlining  Bur  ) 

1916 

Geological  map  of  the  State  of 
California 

1  in.  =  12  mi. 
(1  750.000) 

21 

No  contours 

J  P   Smith 
(State  Mining  Bur  ) 

1938 

Geological  map  of  California 

1  in.  =  8  mi. 
(1:500,000) 

81 

No  contours 

OP  Jenkins 
(Calif.  Div.  Mines) 

1958- 
69 

Geological  atlas  of  California 
(27  sheets) 

1  in.  — 4  mi. 
(1:250.000) 

124 

200  feet 

Jennings.  Strand. 

Rogers  et  al. 

(Calif.  Div   Mines  & 

Geol.) 

1973 

State  of  California,  prelimi- 
nary fault  and  geologic  map 

1  in.  =  12  mi 
(1:750.000) 

52 

No  contours 

C.W.  Jennings 

(Calif  Div.  Mines  & 

Geol.) 

1977 

Geologic  map  of  California 

1  in.  =  12  mi. 
(1:750.000) 

52 

500  feet 

C  W   Jennings 

(Calif   Div.  Mines  & 

Geol.) 

Geologic  Mop  of  California — 1938 

Twenty-two  years  later,  another  milestone  in  California  geo- 
logic maps  appeared  in  the  form  of  a  1:500,CXX)  scale  map  pub- 
lished in  six  sections  by  the  California  Division  of  Mines.  This 
map  was  prepared  by  Olaf  P.  Jenkins,  Chief  Geologist  of  the 
Division  of  Mines,  and  represented  nine  years  of  careful  geologi- 
cal research. 

Much  larger  in  scale  than  any  preceding  geologic  maps  of  the 
state,  the  1938  map  shows  much  more  detail  than  the  earlier 
maps.  The  geologic  boundaries  of  the  81  units  depicted  were 
drawn  with  greater  precision  than  before.  Care  was  taken  to 
follow  the  source  data  faithfully,  and  in  areas  where  no  geologic 
maps  were  available,  or  where  previous  maps  were  too  general 
in  nature  or  at  a  scale  much  smaller  than  the  base  map,  the  area 
was  purposely  left  blank.  This  portrayal  of  the  geology  of  the 
state  showed  that  about  25  percent  of  the  state  was  unmapped. 
The  largest  unmapped  areas  at  that  time  were  in  the  Klamath 
Mountains,  the  northern  Coast  Ranges,  the  southern  Sierra  Ne- 
vada, and  the  desert  areas  of  southeastern  California.  For  the 
first  time,  faults  were  shown  on  an  official  geologic  map  of 
California. 

A  brief  report  heralding  the  new  map  was  published  by  Jen- 
kins (1937).  It  contained  a  history  of  previous  state  geologic 
maps  and  a  description  of  the  new  state  map.  It  also  presented 
a  detailed  listing  of  the  source  data  used  in  the  compilation.  The 
1938  Geologic  Map  of  California  was  prepared  during  the  Great 
Depression  when  funds  were  in  short  supply.  Fortunately,  Dr. 
Jenkins  had  the  services  of  a  number  of  fine  geologists  who  were 
paid  by  the  Federal  government  under  a  Public  Works  Adminis- 
tration (PWA)  program.  Two  PWA  geologists  in  particular, 
Wayne  Galliher  and  Bert  Beverly,  did  the  bulk  of  the  drafting 
and  compilation  (Jenkins,  1976,  p.  31-32).  In  addition,  the  Geol- 
ogy Department  at  Stanford  University  provided  work  space 
near  the  Branner  Memorial  Geological  Library. 


Geologic  Atlas  of  California — 1958-1969 

The  ground  work  for  the  Geologic  Atlas  of  California  began 
in  1951,  after  the  popular  1938  edition  went  out  of  print.  Great 
demand  prompted  Olaf  P.  Jenkins  to  set  up  a  program  for  prepar- 
ing a  new  edition  of  the  state  map  that  would  incorporate  the 
large  amount  of  new  geologic  data  collected  since  the  earlier  map 
was  compiled  (Jahns,  1961). 

Under  Dr.  Jenkins'  direction,  eight  preliminary  sheets  com- 
piled by  Charles  J.  Kundert  were  issued  in  1955.  They  were 
printed  in  black  and  white,  on  a  new  1:250,000  scale  series  of 
Army  Map  Service  base  maps.  These  sheets  covered  much  of  the 
coastal  and  interior  desert  regions  of  southern  California.  The 
base  maps,  however,  were  very  inaccurate,  and  a  few  years  later, 
after  the  Army  Map  Service  had  tremendously  upgraded  the 
quality  of  the  topographic  maps,  these  eight  preliminary  geologic 
map  sheets  became  obsolete. 

Work  on  a  new,  full-color  edition,  utilizing  the  vastly  im- 
proved Army  base  maps,  was  begun  in  1956  by  Charles  W. 
Jennings.  The  first  map  to  be  completed,  the  Death  Valley  Sheet, 
was  published  in  1958.  The  new  edition  was  designated  the  "Olaf 
P.  Jenkins  Edition"  in  recognition  of  the  stimulus  Dr.  Jenkins 
provided  to  geologic  mapping  in  California  during  the  29  years 
he  served  as  Chief  Geologist  and  later  as  Chief  of  the  Division 
of  Mines,  and  in  recognition  of  his  personal  direction  of  the 
program  at  its  inception. 

The  new  State  Geologic  Map  sheets  were  lithographed  and 
published  individually  in  the  same  order  that  the  new  topograph- 
ic base  maps  became  available.  The  standard  map  sheet  covers 
two  degrees  of  longitude  by  one  degree  of  latitude,  but  certain 
sheets  bordering  the  coast  or  containing  irregular  areas  along  the 
Nevada,  Arizona,  and  Mexican  borders  were  combined  to  form 
single  oversize  sheets.  The  topography  of  the  land  surface  is 
expressed  by  a  200-foot  contour  interval,  and  the  Division  added 
the  bathymetry  from  other  sources  for  the  offshore  area  and 


I<585 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


53 


Lake  Tahoe  using  300-foot  contours,  and  for  Salton  Sea  using 
10-foot  contours. 

Shortly  before  the  retirement  of  Dr.  Jenkins,  Charles  Jennings 
was  put  in  charge  of  the  map  compilation  and  Rudolph  Strand 
and  James  Koenig  were  added  as  assistants.  One  of  the  greatest 
problems  facing  the  compilation  project  at  the  onset  was  deter- 
mining the  existence  of  all  the  new  source  data.  The  U.S.  Geolog- 
ical Survey's  excellent  index  to  published  geologic  maps  of 
California  (Boardman,  l'^52)  was  several  years  out-of-date,  and 
no  map  index  to  doctoral  dissertations  and  master's  theses  spe- 
cifically on  California  geology  existed  at  that  time. 

Largely  through  the  efforts  of  Rudolph  Strand,  an  index  to 
published  geologic  maps  was  prepared.  This  index  updates  the 
Boardman  index  through  1956.  Approximately  256  entries  were 
added,  and  the  boundaries  of  all  the  entries  were  plotted  on  a 
new  format  using  the  Army  Map  Service  one  degree  by  two 
degree  quadrangle  units.  The  index  proved  to  be  so  valuable  in 
other  areas  of  the  Division's  work  and  to  geologists  and  others 
outside  the  Division  that  it  was  made  available  by  publication 
(Strand  and  others,  1958). 

Similarly,  an  index  to  graduate  theses  on  California  geology 
was  prepared  in  order  to  identify  and  tap  the  enormous  wealth 
of  geologic  mapping  available  from  this  source.  For  many  areas 
of  the  state,  unpublished  doctoral  dissertations  and  master's 
theses  were  the  only  source  of  geologic  information;  hence  these 
were  essential  to  the  preparation  of  the  State  Geologic  Map.  The 
first  such  index  covered  the  span  of  time  from  1892  (the  earliest 
recorded  thesis  on  a  California  area)  through  1961,  and  also  was 
published  by  the  Division  (Jennings  and  Strand,  1963). 

From  time  to  time  various  staff  members  were  assigned  to  the 
"State  Map  Project."  These  geologists  worked  either  on  a  full- 
time  basis  to  compile  one  or  more  sheets  (Table  9),  or  part-time 
principally  for  field  mapping  to  fill  in  "blank  areas"  or  to  prepare 
additional  source  data  indexes  (see  "Indexes  to  published  geo- 
logic maps"  and  "Indexes  to  theses"  listed  under  "Other  Refer- 
ences" in  Appendix  D). 

Compiling  the  Geologic  Atlas  turned  out  to  be  more  difficult 
than  anticipated.  At  the  outset  of  the  project,  the  difficulties 
associated  with  compiling  a  geologic  map  of  the  entire  state,  with 
all  of  its  geologic  diversity  and  complexity,  were  for  the  most 
part  recognized,  but  it  was  hoped  that  the  abundance  of  new  data 
on  hand  would  make  overcoming  these  difficulties  fairly  simple. 
Actually,  the  inconsistent  nature  of  these  new  data  made  the  task 
more  difficult.  The  source  maps  for  some  areas  of  the  state  were 
excellent;  in  other  areas  they  were  very  poor,  incomplete,  or 
simply  nonexistent.  Frequently,  well-described  areas  were  adja- 
cent to  poorly  understood,  incompletely  mapped,  or  totally  un- 
mapped areas.  Often,  too,  there  was  no  continuity  between  maps 
for  adjacent  areas  because  of  differences  in  geologic  interpreta- 
tion. Thus,  the  compilation  could  easily  have  resulted  in  a  patch- 
work of  data.  Fortunately,  perhaps,  the  scale  of  the  atlas  made 
it  possible  to  ignore  a  multitude  of  discrepancies.  Numerous 
problems,  however,  had  to  be  resolved  in  the  field,  and  almost 
all  blank  areas  in  the  state  were  filled  in  by  a  series  of  reconnais- 
sance mapping  programs  undertaken  by  various  Division  per- 
sonnel. Nevertheless,  in  a  few  areas  of  complex  geology,  or  where 
particularly  detailed  work  was  surrounded  by  less  detailed  map- 
ping, white  areas  were  left  around  the  more  detailed  area  to 
preserve  as  much  information  as  possible. 

Blank  areas  marked  on  the  atlas  sheets  as  "unmapped"  or 
"incomplete"  actually  amount  to  a  very  small  percentage  of 
some  map  sheets  and  are  absent  entirely  from  others.  To  provide 
geologic  data  for  the  large  areas  of  the  state  for  which  there  were 
no  published  or  unpublished  maps  or  theses  available,  the  Divi- 
sion's reconnaissance  geologic  mapping  program  was  initiated  in 
1957.  The  first  mapping  by  the  Division  for  this  purpose  was 


Table  9.      Geologic  Atlas  of  California  (I -.250,000  scale). 


MAP  SHEET 
(by  order  of 
publication] 

YEAR 

COMPILER  (S) 

Death  Vallev 

1968 

C.W-  Jennings 

Alturas 

t958 

I.E.  Gay.  Jr..  and  0  A,  Aune 

San  Luis  Obispo 

1968 

C.W.  Jennings 

Santa  Maria 

1969 

C.W.  Jennings 

Santa  Cruz 

1959 

C  W.  Jennings  and  R.G.  Strand 

Ul<iah 

1960 

C.W.  Jennings  and  R.G.  Strand 

Westwood 

1960 

PA    Lydon.  T.E,  Gay.  Jr..  and  C.W 
Jennings 

Kingman 

1961 

C  W  Jennings 

San  Francisco 

1961 

C.W.  Jennings  and  J,L.  Burnett 

San  Diego-El  Centro 

1%2 

R.G.  Strand 

Long  Beach 

1962 

C.W  Jennings 

Redding 

1962 

R.G.  Strand 

Chico 

1962 

J.L.  Burnett  and  C.W   Jennings 

Trona 

1962 

C.W.    Jennings.    J.L     Burnett    and    8W 
Troxel 

Wallter  Lalie 

1963 

J  B    Koenig 

Santa  Rosa 

1963 

J.B.  Koenig 

Weed 

1964 

R  G    Strand 

Needles 

1964 

C  C.  Bishop 

Baltersfield 

1966 

A.R.  Smith 

Fresno 

1966 

R.A,  Matthews  and  J.L  Burnett 

Santa  Ana 

1966 

T  H,  Rogers 

Sacramento 

1966 

R  G.  Strand  and  J.B.  Koenig 

San  Jose 

1966 

T.H.  Rogers 

Salton  Sea 

1967 

C.W.  Jennings 

Mariposa 

1967 

R.G.  Strand 

San  Bernardino 

1967 

T  H.  Rogers 

Los  Angeles 

1969 

C  W  Jennings  and  R.G.  Strand 

Geologic  Legend  and 
Formation  Index 

1969 

C  W   Jennings  and  R.G.  Strand 

Death  Valley  (revised 

1974 

R.  Streitz  and  M  C.  Stmson 

done  by  T.E.  Gay  and  Q.A.  Aune.  They  mapped  5,400  square 
miles  of  the  Alturas  sheet.  Later  an  additional  5,000  square  miles 
were  mapped  by  T.E.  Gay  and  P. A.  Lydon  for  the  adjacent 
Westwood  sheet.  The  mapping  of  six  15-minute  quadrangles  for 
the  Chico  Sheet  by  M.C.  Stinson  and  J.L.  Burnett  completed  the 
coverage  for  northeastern  California. 

In  the  southern  part  of  the  state,  an  area  equivalent  to  about 
nine  15-minute  quadrangles  was  mapped  in  the  Death  Valley- 
Mojave  Desert  region  largely  by  B.W.  Troxel,  C.H.  Gray,  and 
L.A.  Wright  for  the  Trona  Sheet.  More  than  half  of  the  Salton 
Sea  Sheet  was  previously  unmapped  when  compiling  began  for 
this  area.  However,  as  the  result  of  a  mapping  effort  continued 
through  several  winter  seasons  in  this  desert-mountain  terrain  by 
C.W.  Jennings,  P.K.  Morton,  T.H.  Rogers,  R.B.  Saul,  B.W. 
Troxel,  F.H.  Weber,  and  C.H.  Gray,  this  huge  "blank"  area  was 
covered.  Through  the  efforts  of  F.H.  Weber  and  P.K.  Morton, 
several  15-minute  quadrangle-size  areas  were  mapped  in  San 
Diego  and  Imperial  counties.  The  mapping  of  these  areas  com- 
pleted the  map  down  to  the  Mexican  border.  In  addition,  many 
smaller  areas  in  the  state  were  studied  and  mapped  by  various 
Division  geologists. 


54 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Perhaps  the  most  widespread  and  inaccessible  area  mapped  by 
the  Division  lay  in  the  high  Sierra,  extending  from  near  Lake 
Tahoe  at  the  north  to  the  Tehachapi  Mountains  at  the  south. 
This  mapping  provided  data  for  about  half  of  the  Fresno  Sheet 
and  parts  of  the  Walker  Lake,  Mariposa,  and  Bakersfield  Sheets. 
The  main  objective  of  this  reconnaissance  work  was  to  block  out 
the  major  roof  pendants  in  the  Sierran  batholith  that  heretofore 
had  not  been  mapped,  and  to  delineate  the  remnants  of  volcanic 
deposits  and  extensive  glacial  deposits.  Much  of  this  area  was 
only  accessible  by  backpack  or  horse  and,  because  of  the  high 
elevation  and  snow,  could  only  be  mapped  during  the  summer. 
Fourteen  Division  geologists  contributed  to  this  concerted  effort 
before  the  job  was  completed,  with  the  major  part  done  by  J.L. 
Burnett,  R.A.  Matthews,  and  C.W.  Jennings. 

The  final  sheet  was  completed  in  1968  and  published  in  1969. 
Collectively,  these  works  make  up  the  Geologic  Atlas  of  Califor- 
nia, which  consists  of  27  sheets,  1 10  pages  of  explanatory  data, 
a  master  legend,  and  a  formation  index. 

The  geologic  legend  for  this  atlas  consists  of  124  cartographic 
units.  In  a  state  as  geologically  complex  as  California,  with 
formations  representing  every  geologic  period  known  in  the 
world,  the  choice  of  units  to  show  statewide  such  variety  and 
diversity  in  a  meaningful  way  required  some  special  innovation. 
Olaf  P.  Jenkins  worked  out  an  admirable  legend  for  the  1938 
map,  and  this  with  only  a  few  modifications,  was  also  used  for 
the  atlas  series.  At  first  glance,  the  legend  appears  to  be  based 
principally  on  age,  with  the  exception  of  two  formations,  the 
Franciscan  and  Knoxville  (which  are  very  widespread  in  the 
California  Coast  Ranges).  In  actuality,  the  geologic  contacts 
shown  are  drawn  on  the  basis  of  rock-stratigraphic  units  (forma- 
tions) and  not  time-stratigraphic  units.  The  procedure  followed 
was  to  group  the  numerous  formations  into  "State  Map  Units" 
according  to  (a)  their  relative  stratigraphic  position  (usually 
expressed  by  age);  (b)  their  fundamental  rock  type  (sedimen- 
tary, metasedimentary,  igneous,  and  meta-igneous);  (c)  their 
environment  of  sedimentation  (marine  or  non-marine);  and  (d) 
their  broad  modal  composition  (in  dividing  volcanic  and  pluton- 
ic  rocks  such  as  rhyolite,  andesite,  and  basalt,  or  granite, 
granodiorite,  and  tonalite) .  Genesis  was  the  basis  for  subdividing 
the  various  Quaternary  units  (for  example,  dune  sand,  salt 
deposits,  lake  deposits,  glacial  deposits,  and  terrace  deposits, 
with  the  alluvium  of  the  Great  Valley  province  subdivided  into 
stream  channel  deposits,  fan  deposits,  and  basin  deposits — inter- 
preted largely  from  federal  and  state  soil  survey  maps). 

The  more  prominent  or  well-known  faults  are  identified  by 
name;  however,  no  attempt  was  made  to  distinguish  faults  by  age 
of  latest  movement. 

Accompanying  each  map  sheet  is  an  explanatory  data  sheet 
that  includes  an  index  to  the  geologic  mapping  used  in  the  com- 
pilation, a  table  of  stratigraphic  nomenclature  for  the  units  com- 
piled on  that  sheet,  and  an  index  map  indicating  the  U.S. 
Geological  Survey  topographic  quadrangles  within  the  map 
sheet  area.  Aerial  oblique  photographs  of  salient  geologic  fea- 
tures in  the  map  sheet  area  illustrate  most  data  sheets. 

The  map  is  not  specifically  designed  as  a  wall  map  of  Califor- 
nia, but  rather  as  an  atlas,  suitable  for  use  in  the  field  as  well  as 
in  the  office.  Should  the  entire  map  be  assembled,  however,  (as 
has  been  done  in  several  universities  and  in  the  former  Division 
Headquaters  office  in  San  Francisco),  it  covers  an  area  about  4.6 
X  4.3  meters  (15  x  14  feet).  Although  the  sheets  were  published 
individually  over  a  period  of  1 1  years,  all  the  colors  and  patterns 
of  the  geologic  units  were  integrated  as  closely  as  possible  so  that 
adjacent  sheets  match  in  continuity  of  units  and  color.  Thus, 
adjacent  sheets  can  be  trimmed  and  joined  in  any  size  block,  if 
desired. 


Two  Small-Scale  Geologic  Mops  of 
California   (1966  and  1968) 

Two  relatively  recent  lithographed  maps  of  the  state,  although 
of  much  smaller  scale  than  the  previously  described  maps, 
should  be  mentioned.  The  first  of  these  was  compiled  jointly  by 
the  U.S.  Geological  Survey  and  the  Cahfomia  Division  of  Mines 
and  Geology  at  a  scale  of  l;2,50O,(X)O.  It  was  published  by  the 
U.S.  Geological  Survey  (1966)  as  "Miscellaneous  Geological 
Investigations  Map  1-512"  and  has  been  reprinted  or  copied  in 
several  different  formats  in  various  other  publications.  This 
highly  diagrammatic  map  vividly  portrays  the  major  rock  units 
by  1 1  subdivisions — three  Cenozoic  (marine,  nonmarine,  vol- 
canic), three  Mesozoic  (principally  sedimentary),  one  Paleozoic 
(sedimentary  and  volcanic),  one  Precambrian  (all  rock  types), 
a  Pre-Cenozoic  metamorphic  rock  unit,  Mesozoic  granitic  rocks, 
and  lastly,  ultramafic  rocks.  Faults  are  shown  with  heavy  black 
lines,  and  direction  of  apparent  movement  is  indicated  by  ar- 
rows. The  base  is  without  roads,  and  only  a  few  major  cities  and 
geographic  features  are  identified.  This  map  effectively  displays 
the  most  prominent  geologic  features  of  the  state,  and  has  en- 
joyed considerable  popularity. 

The  second  map  was  prepared  and  published  by  the  American 
Association  of  Petroleum  Geologists  (1968)  as  part  of  their 
Geologic  Highway  Map  Series.  It  includes  Nevada  as  well  as 
California  and  is  at  a  scale  of  1  inch  equals  approximately  30 
miles.  Twenty-nine  geologic  units  are  depicted,  but  because  their 
identification  is  obscure  and  their  description  is  scattered  among 
five  separate  legends,  five  columnar  sections,  and  lengthy  explan- 
atory notes,  using  the  map  is  cumbersome.  The  back  of  the  map 
is  filled  with  cross  sections,  a  geologic  history,  a  physiological 
map,  and  a  tectonic  map. 


GEOLOGIC  MAP  OF  CALIFORNIA— 
1977 

History  of  the  Project 

Even  before  the  1:250,000  scale  Geologic  Atlas  of  California 
was  completed,  it  was  recognized  that  a  smaller-scale  map  of  the 
state,  one  that  would  present  an  overview  of  the  geology  of  the 
entire  state,  was  highly  desirable.  It  had  become  apparent  that 
the  individual  atlas  sheets,  as  useful  as  they  were  for  field  and 
office  purposes,  were  not  satisfactory  for  evaluation  of  statewide 
geologic  and  structural  trends.  Therefore,  late  in  1965,  plans 
were  made  for  a  1:750,000  scale  map  of  California  (Jennings, 
1965). 

After  consideration  of  various  scales,  1:750,000  was  chosen 
because  the  resulting  size,  about  1.4  x  1.5  meters  (4.5  x  5  feet) 
is  convenient  for  fitting  on  an  average  office  or  classroom  wall. 
In  addition,  this  scale  is  consistent  with  the  first  two  official 
geologic  maps  of  Cahfornia  published  by  the  State  in  1891  and 
1916,  and  the  scale  is  also  sufficiently  large  to  show  a  significant 
amount  of  geologic  information. 

Almt)st  two  years  passed,  however,  before  work  on  compiling 
this  new  map  could  begin.  A  pilot  compilation  of  the  Chico  Sheet 
area,  using  a  newly  devised  legend,  incorporating  such  new  data 
necessary  for  classifying  the  faults,  and  adding  fold  axes  and 
other  structural  data,  was  then  started  by  C.W.  Jennings.  It  soon 
became  apparent  that  considerable  updating  of  the  geologic  data 
for  most  of  the  map  sheets  would  be  necessary  because  many  of 
the  published  atlas  sheets  were  already  several  years  old  and  a 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


55 


large  quantity  of  new  geologic  map  data  was  available  for  a  good 
part  of  the  state. 

At  the  beginning  of  the  project,  it  was  decided  that  a  multipur- 
f)Ose  map  of  the  state  would  be  most  desirable.  In  addition  to  the 
geology,  the  map  would  emphasize  recently  active  faults,  recent 
volcanic  rocks  and  volcanoes,  thermal  springs,  offshore  struc- 
tures, and  major  fold  axes.  Therefore,  all  these  data  were  plotted 
on  the  work  sheets;  but  it  became  evident  that,  for  publication 
purposes,  it  would  be  much  more  effective  to  separate  some  of 
this  information  and  make  two  maps  rather  than  one.  Pursuing 
this  concept,  it  was  planned  to  present  a  series  of  maps  at  the 
same  1:750,000  scale  illustrating  various  geologic  and  geophysi- 
cal parameters  that  can  conveniently  be  studied  individually  or 
in  relation  to  one  another.  Thus,  the  first  map  in  this  series  is  the 
Fault  Map  of  California  With  Locations  of  Volcanoes,  Thermal 
Springs  and  Thermal  Wells.  The  Geologic  Map  of  California  is 
Geologic  Data  Map  No.  2.  The  third  in  the  series  will  be  a 
Gravity  Map  of  California,  which  is  nearing  completion.*  Other 
maps  in  the  series,  such  as  an  epicenter  map  and  aeromagnetic 
map,  are  in  the  planning  stage.  In  addition,  consideration  is 
being  given  to  periodically  update  and  revise  the  Fault  Map  of 
California,  because  of  the  rapid  rate  at  which  new  information 
is  being  generated  and  because  of  the  growing  demand  for  such 
data  in  city  and  county  seismic  safety  planning,  and  in  the  loca- 
tion of  schools,  hospitals,  nuclear  power  plants,  and  other  engi- 
neering works. 

A  preliminary  draft  of  the  1:750,000  geologic  map  was  com- 
plete in  197 1,  and  it  accompanied  a  report  entitled  "Urban  Geol- 
ogy Master  Plan  for  California"  (Bruer,  1971),  which  was 
financed  by  the  Federal  Department  of  Housing  and  Urban 
Development.  Many  areas  on  the  map,  however,  were  still  shown 
in  a  tentative  state  and  the  map  needed  additional  work  pending 
receipt  of  new  information.  The  map  also  required  more  editing 
and  generalization  in  complex  areas.  This  work  was  accom- 
plished and  the  compilation  was  complete  in  1972. 

Because  of  the  complexity  of  the  map,  a  hand-tinted  copy  of 
the  map  was  carefully  prepared  and  then  photographed  and 
full-scale  color  prints  were  made.  These  colored  prints  proved 
very  helpful  in  the  extensive  reviewing  process  that  the  map  then 
underwent  by  more  than  forty-five  geologists  conversant  with 
California  geology.  Reviewers  from  outside  the  Division  includ- 
ed personnel  from  the  U.S.  Geological  Survey,  universities,  other 
federal  and  state  agencies,  and  a  number  of  consulting  geologic 
firms.  The  review  was  completed  in  about  six  months,  and  exten- 
sive revisions  and  additions  were  then  made  to  the  master  compi- 
lation. Because  of  the  demand  for  the  information  on  this  map, 
an  uncolored  version  of  the  original  hand-drafted  compilation 
was  published  (see  "Preliminary  fault  and  geologic  map  of  Cali- 
fornia— 1973"  in  Part  I  of  this  report).  Work  also  began  in 
scribing  and  preparing  the  plates  for  the  fault  map  portion  of  the 
compilation.  Scribing  of  the  geologic  contacts  for  the  "Geologic 
Map  of  California"  did  not  begin  until  January  1975,  when 
drafting  help  became  available.  During  the  final  stages  of  scrib- 
ing and  preparing  of  the  printing  plates,  some  additional  correc- 
tions of  the  geology  were  made,  and  new  data  for  a  few  selected 
areas  were  added.  The  bulk  of  the  data  shown,  however,  is 
only  complete  to  1973. 

•Editor's  nole:  Geologic  Data  Map  No.  3,  Gravity  Map  of  California  and  its 
Continental  Margin,  and  Geologic  Data  Map  No  4.  Geotherma!  Resources  Map 
of  California,  ha\c  been  published  since  this  was  writtcn. 

Uses  Of  The  Geologic  Map 

The  usefulness  of  the  Fault  Map  of  California,  whose  intimate 
relationship  to  earthquakes  is  easy  to  explain,  is  generally  appar- 


ent. This  is  not  the  case,  however,  with  a  geologic  map  of  the 
state,  the  use  of  which  is  difficult  to  explain  to  the  nongeologist. 
Dr.  P.B.  King  and  H.M.  Beikman  of  the  U.S.  Geological  Survey 
discussed  this  difficulty  in  their  explanatory  text  for  the  Geologic 
Map  of  the  United  States  (King  and  Beikman,  1974).  Their 
explanation  is  succinctly  expressed,  and  because  it  applies  as  well 
to  the  Geologic  Map  of  California  as  it  does  to  the  Geologic  Map 
of  the  United  States,  we  quote  at  length  from  it  here: 

Sometimes,  when  we  explain  to  nongeologists  our  project 
for  a  Geologic  Map  of  the  United  States,  we  are  dismayed 
when  asked,  "What  good  is  it?"  We  compilers,  enmeshed 
in  our  many  problems  of  assembling,  collating,  and  gener- 
alizing the  source  data  for  the  map,  find  it  difficult  to 
produce  a  ready  answer  to  this  question.  Nevertheless,  the 
values  and  uses  of  an  accurate  geologic  map  are  manifold, 
not  only  to  geologists,  but  to  the  public  at  large. 

First  of  all,  of  course,  the  map  displays  the  rocky  founda- 
tions on  which  our  country  is  built  and  is  a  summation  of 
the  nearly  two  centuries  of  investigation  of  this  foundation 
by  a  succession  of  geologists.  It  is  thus  a  reference  work 
that  present  and  future  geologists  of  the  country  can  con- 
sult and  is  of  prime  importance  in  the  education  of  earth 
scientists  in  schools  and  colleges.  Further,  it  can  be  con- 
sulted by  geologists  in  other  countries  and  continents  who 
wish  to  learn  about  the  geology  of  the  United  States;  they 
will  compare  the  map  with  similar  national  or  continental 
maps  of  their  own  countries. 

In  terms  of  resources  useful  to  man,  the  Geologic  Map  lays 
out  accurately  the  major  regions  of  bedrock  in  the  United 
States  upon  which  many  facets  of  our  economy  depend.  It 
illustrates  the  areas  of  stratified  rocks  that  are  the  sources 
of  most  of  our  fuels,  and  the  areas  of  crystalline,  plutonic, 
and  volcanic  rocks  that  contain  important  parts  of  our 
mineral  wealth.  The  map  shows  areas  of  complex  folding 
and  faulting,  parts  of  which  are  still  tectonically  unstable 
and  subject  to  earthquake  hazards.  To  some  extent  the 
bedrock  represented  on  the  map  also  influences  the  surface 
soils,  which  are  of  interest  in  agriculture  and  engineering 
works. 

Beyond  this,  the  practical  value  of  the  map  is  less  tangible, 
although  it  can  be  an  important  tool  for  the  discerning 
user.  Clearly,  the  map  will  not  pinpoint  the  location  of  the 
next  producing  oil  well  or  the  next  bonanza  mine,  nor  will 
it  give  specific  advice  for  the  location  of  a  dam  or  a  reactor 
site;  these  needs  can  only  be  satisfied  on  maps  on  much 
larger  scales,  designed  for  specific  purposes.  Nevertheless, 
the  sapient  exploration  geologist  can  find  upon  it  signifi- 
cant regional  features  not  apparent  to  the  untrained  user. 
Important  mineral  deposits  cluster  along  regional  tec- 
tonic trends  or  chains  of  plutons  of  specific  ages.  Final- 
ly, the  Geologic  Map  will  be  used  in  national  planning 
activities  in  conjunction  with  other  national  maps  showing 
environmental  features  such  as  climate,  vegetation,  and 
land  use — for  the  location  of  power  transmission  corri- 
dors, highways.  National  Parks,  wilderness  areas,  recla- 
mation projects,  and  the  like. 

In  essence,  the  Geologic  Map  of  California  is  simply  a  repre- 
sentation of  a  part  of  the  earth's  surface.  It  shows  the  distribution 
of  the  rock  units  that  occur  at  the  surface,  and  tells  us  something 
of  their  composition  and  origin,  as  well  as  their  relative  degree 
of  hardness — a  clue  to  their  resistance  to  erosion.  In  addition,  the 
map  shows  by  appropriate  symbols  where  and  how  the  rocks  are 
folded  and  faulted. 


56 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Objectives  and  Contents 

Ideally,  the  geologic  map  represents  the  various  features  that 
one  would  find  on  a  visit  to  any  locality  on  the  map.  Of  course, 
the  amount  of  detail  that  can  be  depicted  is  limited  by  the  scale, 
but  the  most  important  geologic  features  are  portrayed.  During 
the  compilation  this  factor  was  continually  kept  in  mind;  where 
necessary,  particularly  significant  geologic  features,  even  if 
small,  were  exaggerated  in  order  to  portray  them.  Likewise,  in 
some  places  the  geology  is  generalized  in  order  that  the  most 
important  features  are  not  lost  in  a  maze  of  detail.  The  geologic 
map  of  the  state  is  first  and  foremost  a  factual  documentation  of 
the  distribution  of  rocks  in  the  state;  it  is  secondarily  an  indicator 
of  the  presence  of  major  folds  and  faults  where  known.  As  such, 
the  Geologic  Map  of  California  should  be  the  kind  of  data  source 
that  can  be  used  to  build  theory  as  closely  grounded  in  reality 
as  possible. 

Although  the  Geologic  Map  of  California  confines  itself  with- 
in the  political  boundaries  of  the  state,  during  its  construction 
attention  was  given  to  the  geologic  data  for  adjacent  areas  pro- 
vided by  maps  of  Arizona,  Oregon,  Nevada,  and  Baja  California. 
In  the  Pacific  Ocean  area,  the  map  does  not  attempt  to  show 
geologic  units  (largely  because  of  the  unavailability  of  data). 
However,  the  major  offshore  structural  features  are  shown.  Data 
on  offshore  faults  and  folds  are  rapidly  accruing,  due  largely  to 
the  increasing  efforts  by  the  U.S.  Geological  Survey  and  certain 
universities  and  other  institutions.  Unfortunately,  the  wealth  of 
offshore  knowledge  possessed  by  the  petroleum  exploration  com- 
panies is  largely  unavailable. 

Representation  of  Faults 

The  location  of  faults  shown  on  the  Geologic  Map  of  Califor- 
nia are  the  same  as  those  shown  on  the  Fault  Map  of  California, 
but  the  faults  are  not  color-coded  according  to  recency  of  move- 
ment. Thus,  all  faults  on  the  Geologic  Map  are  shown  as  black 
hnes,  and  no  distinction  is  made  between  historic.  Quaternary, 
or  pre-Quatemary  faults.  The  symbology  showing  sense  of 
movement  on  faults  is  the  same  for  both  maps:  pairs  of  half- 
arrows  for  direction  of  lateral  displacement  along  a  fault,  arrows 
showing  direction  of  dip  of  a  fault  plane  or  fault  surface,  and 
letters  U  and  D  for  relative  up  and  down  movement  along  a  fault. 

Representation  of  Contacts 

All  contacts  between  map  units  are  shown  on  the  Geologic 
Map  of  California  as  solid  fine  lines  except  where  the  map  units 
are  bounded  by  faults  (depicted  by  a  thicker  line),  regardless  of 
the  rehability  of  the  contact  on  the  original  data  source.  The 
reader  is  referred  to  the  1  ;250,0OO  scale  Geologic  Atlas  or  to  the 
original  source  data  (indexed  in  Appendix  D)  for  details  as  to 
the  nature  of  the  various  contacts. 

In  several  places  in  the  Coast  Ranges  where  "Franciscan  me- 
lange" is  depicted,  there  may  be  no  contact  between  it  and  the 
"undifferentiated"  Franciscan  Complex  because  of  incomplete 
knowledge  of  the  area.  In  such  places  the  pattern  alone  separates 
"melange"  from  undifferentiated  Franciscan. 

In  a  few  places  where  mapping  or  paleontological  control  is 
inadequate  to  distinguish  between  map  units  of  similar  rock 
types,  a  combination  map  symbol  has  been  used.  For  example, 
there  is  shown  on  the  map  in  the  northern  Coast  Ranges,  E-Ep 
(Eocene-Paleocene  marine  undifferentiated);  in  the  southern 
Coast  Ranges,  Ku-Ep  (Upper  Cretaceous-Paleocene  marine  un- 
differentiated) ;  and  on  Santa  Catalina  Island,  M  -|-  KJf  (Miocene 


marine  together  with  Franciscan  rocks).  In  each  case,  the  color 
used  for  the  unit  is  the  color  of  the  first  indicated  symbol,  which 
suggests  the  more  likely  or  more  predominant  unit  of  the  combi- 
nation. 

In  editing  the  final  map,  the  writer  tried  to  keep  in  mind  not 
only  the  large-scale  features  that  illustrate  the  geologic  frame- 
work of  the  state  and  that  should  be  apparent  even  when  viewing 
the  map  from  a  distance,  but  also  to  retain  important  details  for 
which  the  state  is  noted,  and  which  can  be  seen  on  close  in- 
spection of  the  map. 

Compilation  Method 

For  those  who  may  be  embarking  on  their  own  statewide 
geologic  map  compilation,  and  for  those  who  are  interested,  the 
method  used  in  compiling  and  pubhshing  the  Geologic  Map  of 
California  will  be  described.  There  are  probably  as  many  meth- 
ods of  compiling  as  there  are  compilers,  each  method  having  its 
own  advantages  and  disadvantages.  The  method  described  here, 
devised  through  trial  and  error,  was  found  suitable  for  our  pur- 
poses. The  method  essentially  consists  of  six  steps  in  compiling 
followed  by  two  steps  for  publication  outlined  as  follows; 

1.  Search  and  collection  of  source  data. 

2.  Evaluation  and  generalization  of  data. 

3.  Reduction  to  the  compilation  scale. 

4.  Plotting  on  the  master  base. 

5.  Further  generalization  and  editing. 

6.  Review  and  correction. 

7.  Preparation  of  printing  plates. 

8.  Final  proof  and  publication. 

1.  Search  and  collection  of  source  data:  No  compilation  is 
better  than  the  sources  upon  which  it  is  based.  For  this  reason, 
a  large  amount  of  the  effort  involved  in  a  good  compilation  is 
spent  searching  out  the  best  available  data.  We  in  California  are 
fortunate  to  have  a  data  bank  of  map  sources  going  back  many 
years.  This  data  bank  was  started  in  the  1930s  by  Dr.  Olaf  P. 
Jenkins,  Chief  Geologist  of  the  Division  of  Mines,  who  came  to 
the  Division  in  1929  to  prepare  a  new  geologic  map  of  California. 
Much  of  the  data  contained  in  Dr.  Jenkins'  collection  of  maps 
has  been  superseded  by  more  detailed  work,  but  certain  data, 
especially  unpublished  data  covering  remote  areas  of  the  state, 
are  still  useful  or  valuable  for  their  historical  content. 

When  the  preparation  of  the  1:250,0(X)  scale  Geologic  Atlas 
of  California  was  undertaken,  the  files  of  Dr.  Jenkins  were  reor- 
ganized into  r  X  2°  units,  corresponding  to  the  atlas  sheets,  and 
each  piece  of  information  was  evaluated  and  either  saved  or 
rejected.  As  new  data  were  acquired,  they  were  systematically 
added  into  the  collection.  By  1973  the  data  bank  had  expanded 
from  less  than  a  single  five-drawer  file  cabinet  to  six  such  cabi- 
nets and  a  number  of  roll-map  files — and  it  is  still  growing.  Then, 
as  now,  the  amount  of  new  data  generated  every  year  was  so 
great  (and  becoming  greater  each  year — see  Figures  1  and  2) 
that  even  a  brief  suspension  of  data  gathering  would  seriously 
compromise  the  usefulness  of  the  data  collection. 

In  order  to  ensure  completeness  in  gathering  published  data, 
one  can  refer  to  source  indexes  such  as  that  published  by  the  U.S. 
Geological  Survey  (Boardman,  1952).  However,  we  found  that 
the  published  indexes  lagged  far  behind  publication  of  new  data. 
Thus,  we  had  to  develop  our  own  indexes,  and  considerable  time 
and  effort  were  expended  in  this  direction  (see  Strand  and  oth- 
ers, 1958;  Koenig  and  Kiessling,  1968;  Kiessling,  1972;  and 
Kiessling  and  Peterson,  1977). 

We  found  the  largest  source  of  unpublished  geologic  map 
information  on  California  in  universities  and  colleges,  in  the 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


57 


form  of  theses  and  dissertations  for  advanced  degrees — especial- 
ly in  the  fields  of  geology,  seismology,  paleontology,  oceanogra- 
phy, geophysics,  and  geochemistry.  Here  too,  no  complete  or 
up-to-date  indexes  existed,  and  much  time  was  spent  in  prepar- 
ing our  own  indexes  and  gathering  the  data  (see  Jennings  and 
Strand,  1963;  Taylor,  1974;  Peterson  and  Saucedo,  1978). 

Other  unpublished  sources  of  information  include  oil  com- 
pany and  mining  company  maps.  However,  little  surface  map- 
ping is  done  in  oil  exploration  today — the  bulk  of  the  effort  going 
into  subsurface  interpretations.  The  numerous  surface  maps  ex- 
isting in  the  older  files  of  oil  companies  were  occasionally  used, 
but  all  too  often  gaining  access  to  them  was  difficult  or  impossi- 
ble. Moreover,  there  was  no  way  to  know  whether  data  for 
certain  areas  even  existed  in  company  files . 

Maps  by  mining  companies  consist  mostly  of  underground 
workings.  Often  their  areal  coverage  is  so  narrow  as  to  be  of 
limited  usefulness  for  regional  compilations.  However,  regional 
mining  exploration  maps  have  been  made  for  remote  areas  where 
mineral  deposits  occur,  and  these  maps  can  be  very  useful.  When 
such  maps  were  known  to  exist  and  to  be  available,  they  were 
used. 

One  other  source  of  valuable  unpublished  data  is  work  under 
way,  especially  work  that  is  nearly  complete.  Numerous  maps  of 
this  kind  were  made  available  by  the  U.S.  Geological  Survey,  the 
Division  of  Mines  and  Geology,  other  state  or  federal  agencies, 
and  universities. 

2.  Evaluation  and  generalization  of  data:  Oftentimes  more 
than  one  interpretation  of  the  geology  of  a  given  area  exists,  and 
the  compiler  must  choose  which  to  use.  Usually,  the  most  recent 
map  is  chosen  on  the  premise  that  the  geologist  has  made  use  of 
pre-existing  data  and  has  correspondingly  improved  on  that 
body  of  information.  This  is  usually  the  case,  but  not  always.  The 
area  of  geologic  interest  or  the  objectives  of  later  mappers  may 
have  been  different  from  the  earlier  workers,  and  deliberate 
omissions  in  their  maps  may  have  been  made.  The  compiler  must 
always  be  on  the  lookout  for  such  possibilities. 

After  the  data  have  been  evaluated,  a  tracing  of  the  mapped 
area  is  made  for  inclusion  into  the  compilation.  The  tracing  is 
done  on  an  overlay  of  either  good-quality  tracing  vellum  or 
polyester  drafting  film.  The  advantage  of  using  drafting  film  is 
that,  with  its  superior  transparency,  it  can  be  seen  through  with- 
out the  use  of  a  light  table.  Drafting  film,  of  course,  is  also 
scale-stable.  The  original  mapped  units  are  combined  according 
to  a  predetermined  legend,  and  the  contacts  are  then  generalized 
in  accordance  with  the  amount  of  reduction  that  will  be  required. 

3.  Reduction  to  the  compilation  scale:  The  tracings  of  the 
combined  and  generalized  units  are  marked  with  a  bar-scale 
showing  the  amount  of  reduction  required  to  fit  the  master  base 
map.  A  few  major  roads,  or  intersecting  latitude  and  longitude 
lines,  are  drawn  on  the  tracing  in  order  to  verify  the  amount  of 
reduction  or  to  provide  control  for  adjusting  any  distortion  that 
might  exist  in  the  source  map.  The  tracings  are  then  photograph- 
ically reduced  to  accurately  fit  the  compilation  base  map.  For  the 
Geologic  Atlas,  reduction  was  made  to  the  final  publication 
scale,  that  is,  1 :250,000.  In  prepanng  the  1 :750.000  scale  Geolog- 
ic Map  of  California,  intermediate  -  scale  work  sheets  at  1 :250,- 
000  scale  were  prepared  and  later  reduced  to  the  1:750,000 
publication  scale. 

The  photographic  reduction  technique  used  most  successfully 
and  efficiently  by  the  Division  was  performed  by  high-quality 
engineering  reproduction  firms  equipped  with  large  cameras, 
vacuum  frames,  and  photographic  processing  labs.  The  proce- 
dure for  this  technique  consists,  first,  of  making  a  105-mm  nega- 
tive of  the  tracing,  utilizing  a  vacuum  frame  to  ensure  a  fiat 


surface  of  the  tracing.  The  negative  is  then  used  to  photograph- 
ically print  a  positive  image  on  sensitized  drafting  film.  At  the 
same  time  the  image  is  enlarged  to  the  precise  size  indicated  by 
the  bar-scale  shown  on  the  tracing. 

4.  Plotting  on  the  master  base:  The  master  compilation  base 
map  must  be  scale-stable  material.  This  is  absolutely  essential  in 
the  publication  process  following  the  completion  of  the  compila- 
tion. The  base  map  shows  at  a  minimum  the  roads,  railroads, 
streams,  lakes,  and  topographic  contours.  These  features  are 
printed  on  the  reverse  side  of  the  base  so  that  any  erasures  or 
changes  in  the  geologic  compilation  will  not  destroy  the  base 
map  features.  Showing  the  culture  and  topography  in  one  color 
and  the  streams  and  lakes  in  another  makes  it  easy  to  distinguish 
between  the  two  while  plotting  the  geology.  The  geologic  con- 
tacts are  then  drawn  onto  the  master  base  utilizing  black  draw- 
ing ink  and  technical  pens.  A  fine  point  is  used  for  normal 
contacts  and  a  broader  point  for  fault  contacts. 

Invariably  additional  generalization  and  simplification  are  re- 
quired at  this  stage.  Now  that  these  data  have  been  reduced  to 
the  actual  publication  scale,  it  is  possible  to  visualize  the  final 
product  and  to  begin  generalizing  the  data.  The  compiler's  objec- 
tive is,  of  course,  to  present  a  picture  that  is  as  definitive  as 
possible  and  that  has  both  clarity  and  intelligent  emphasis.  To 
reach  this  goal,  the  compiler  usually  must  make  compromises 
dictated  by  the  limits  of  space  and  legibility.  Often  the  compiler 
finds  that  he  has  more  geologically  significant  features  to  portray 
than  space  on  the  map  to  portray  them,  and  he  will  have  to 
choose  what  to  show  and  what  to  leave  out,  relying  on  his 
interpretation  of  the  relative  importance  of  the  available  data. 

5.  Further  generalization  and  editing:  After  each  of  the  indi- 
vidual reduced  segments  have  been  plotted  and  such  inevitable 
problems  as  "dangling  contacts"  and  mismatches  have  been  re- 
solved (perhaps  by  consultation  with  the  individual  geologist,  by 
compromises,  or  by  field  examination),  the  map  is  ready  for  an 
overview  evaluation.  At  this  point,  attention  is  given  to  such 
factors  as  balance  (areas  where  too  much  detail  is  shown),  clari- 
ty (taking  a  more  detached  look  at  the  overall  map),  and  empha- 
sis ("can't  see  the  forest  for  the  trees").  A  most  useful  aid  at  this 
step  is  the  preparation  of  a  hand-colored  copy  of  the  map.  This 
may  be  a  long  and  exacting  task,  but  its  value  cannot  be  overesti- 
mated. With  a  hand-colored  map,  consideration  of  the  above 
mentioned  factors  is  greatly  facilitated  and  many  problems 
become  glaringly  apparent. 

6.  Review  and  correction:  Before  the  compilation  is  submitted 
for  publication,  it  is  advisable  to  have  the  map  reviewed  by 
experts  conversant  with  wide  areas  of  regional  and  detailed  geol- 
ogy of  the  area.  During  preparation  of  the  Geologic  Map  of 
Cahfomia,  we  were  fortunate  to  have  the  benefit  of  extensive 
reviews  by  a  wide  range  of  professionals  affiliated  with  the  U.S. 
Geological  Survey,  and  universities,  other  State  of  California  and 
Federal  agencies,  as  well  as  a  number  of  consulting  geologists 
and  firms.  Each  reviewed  our  maps  with  great  interest  and  dedi- 
cation. 

Following  the  review  process,  the  various  comments,  correc- 
tions, and  suggested  additions  are  evaluated  and  the  necessary 
changes  incorporated  in  the  master  compilation. 

7.  Preparation  of  printing  plates:  After  the  map  compilation 
is  submitted  for  publication,  it  becomes  a  job  for  the  drafting 
staff  and  lithographer.  However,  the  responsibility  for  checking 
the  work  submitted  to  the  lithographer  still  falls  on  the  compiler. 
Inevitably,  no  matter  how  carefully  the  compilation  has  been 
prepared,  problems  will  be  encountered  which  only  the  geolo- 
gist-compiler can  resolve. 


58 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


It  is  usually  beyond  the  knowledge  and  experience  of  the 
geologist-compiler  to  tell  the  drafting  staff  how  to  make  the  map 
ready  for  the  printer.  However,  the  compiler  should  understand 
something  of  the  printing  procedure  in  order  to  recognize  some 
of  the  problems  in  preparing  the  printing  plates.  A  summary  of 
the  steps  involved  in  this  procedure  is  as  follows;  First,  the 
compilation  must  be  photographically  transferred  to  a  sensitized 
drafting  film  in  order  that  the  contacts  and  faults  can  be  scribed 
(engraved).  These  are  first  scribed  solid  so  that  the  necessary 
"peelcoats"  for  each  of  the  formation  colors  and  patterns  can  be 
made  by  the  lithographer.  Then  the  contacts  and  faults,  which 
were  scribed  as  solid  lines,  are  "dashed"  where  required  by 
opaqueing,  usually  utilizing  a  "visitype"  pattern  on  a  transparent 
overlay  sheet.  Similarly,  overlays  are  prepared  using  "visitype" 
for  dotted  faults,  queried  faults  and  queried  contacts,  thrust  fault 
"barbs,"  fault  attitudes,  formation  symbols,  volcano  symbols, 
fault  names,  hot  springs  and  well  locations,  and  any  other  special 
symbols.  Some  of  these  symbols  can  be  combined  on  the  same 
overlay,  but  usually  certain  ones  are  kept  separate  if  the  map  is 
to  be  printed  in  various  forms  for  other  purposes  where  simplica- 
tion  may  be  required  or  different  colors  are  to  be  used — for 
example,  color-coded  faults  for  a  fault  map  and  uncolored 
(black)  faults  for  a  geologic  map.  Lastly,  an  overlay  for  the 
explanation,  titles,  and  other  peripheral  data  is  prepared. 

The  plates  and  overlays  of  the  contacts,  faults,  and  the  forma- 
tion symbols  are  then  photographically  combined,  and  a  film 
positive  is  made  of  the  combination.  Ozalid  prints  of  this  com- 
posite plate  are  made,  and  these  are  hand-colored  for  use  as  color 
guides  by  the  lithographer  when  the  peelcoats  are  made. 

8.  Final  proof  and  publication:  After  all  the  necessary  scribed 
plates  and  overlays  are  prepared,  the  hand-colored  guides  made, 
and  a  color  and  pattern  scheme  selected,  the  "map"  is  ready  to 
send  to  the  lithographer.  In  addition  to  the  above,  a  dummy 
layout  is  included,  together  with  instructions  concerning  the 
various  plates  for  the  base  map  (previously  acquired  from  the 
U.S.  Geological  Survey).  After  these  materials  are  sent  to  the 
lithographer,  the  job  for  the  compiler  and  drafting  staff  does  not 
end,  because  the  extremely  important  task  of  proofing  is  yet  to 
come. 

After  the  lithographer  prepares  the  printing  plates,  the  first 
color  proof  will  arrive.  The  compiler  will  be  especially  interested 
in  seeing  how  the  selected  color  scheme  appears.  Do  the  colors 
show  up  properly?  Can  units  be  adequately  distinguished?  Are 
the  color  shades  aesthetically  pleasing?  Changes  in  colors  or 
patterns  may  be  required  before  the  second  proof  is  prepared. 
The  drafting  staff,  in  the  meantime,  will  make  a  careful,  sys- 
tematic search  for  printer's  errors  in  the  placement  of  colors 
and/or  patterns.  Everyone,  of  course,  will  be  interested  in  how 
the  layout  appears,  the  titles,  explanations,  and  legend.  After  all 
the  discovered  errors  have  been  noted,  and  instructions  to  the 
lithographer  for  any  changes  in  color  and  layout  have  been 
made,  the  lithographer  will  correct  and  change  the  printing 
plates  accordingly  and  a  second  proof  will  be  prepared.  This 
procedure  will  be  repeated  until  satisfaction  by  all  concerned  is 
attained.  The  map  is  then  ready  for  printing. 


Classification  of  Rock  Units  and 
Special  Problems 

The  rock  units  selected  for  the  new  Geologic  Map  were  largely 
derived  from  the  legend  for  the  1:250,000  scale  atlas  sheets.  The 
124  units  shown  on  the  1:250,(XX)  scale  series  have  been  com- 
bined into  52  units.  Fewer  units  are  used  as  a  result  of  fewer 


subdivisions  within  epochs  or  periods;  for  example,  Miocene 
marine  sedimentary  rocks  are  shown  rather  than  uppei,  middle, 
and  lower  Miocene  marine  sedimentary  rocks.  Table  10  illus- 
trates how  the  units  of  the  1:250,000  scale  Geologic  Atlas  of 
California  have  been  grouped  into  the  new  1:750,000  scale  Geo- 
logic Map  of  California. 

From  Table  10,  it  might  appear  that  the  units  shown  on  the 
map  are  defined  by  time  lines,  but  they  are  in  fact  drawn  on 
formation  boundaries.  For  convenience,  formations  of  approxi- 
mately the  same  age  and  origin  are  grouped  under  the  same 
symbol.  Thus,  all  the  marine  formations  of  Miocene  or  predomi- 
nantly Miocene  age  are  shown  as  "M,"  and  all  the  volcanic  rocks 
of  Miocene  or  predominantly  Miocene  age  are  shown  as  "Mv." 
Although  the  boundaries  shown  on  the  map  are  drawn  on  the 
basis  of  mapped  formations,  only  the  Franciscan  Complex  is 
separately  identified.  This  exception  is  warranted  because  of  the 
Franciscan's  widespread  extent,  its  time  span  of  deposition  (Ju- 
rassic through  Cretaceous),  and  its  importance  in  the  under- 
standing of  California  geologic  history. 

For  reference  purposes,  a  complete  listing  of  all  formations 
grouped  within  each  of  the  units  shown  on  the  Geologic  Map  of 
California  is  included  in  Appendix  C.  The  Geologic  Legend  of 
the  map  contains  brief  descriptions  of  the  units  indicating  the 
predominant  lithologic  types.  Among  the  Cenozoic  rocks,  a 
statement  is  also  included  to  indicate  the  degree  of  consolidation. 
This  could  be  useful  in  estimating  relative  slope  stability,  ground 
shaking  during  earthquakes,  erosion  resistance,  and  liquifaction 
potential. 

The  plan  for  classification  of  the  rock  units  in  the  Geologic 
Legend,  which  is  reproduced  in  Figure  15,  follows  a  systematic 
scheme.  The  rock  units  have  been  broadly  classified  into  sedi- 
mentary, volcanic,  metamorphic,  and  plutonic  lithologic  groups, 
and  are  arranged  in  normal  stratified  sequence  with  the  oldest 
rocks  at  the  bottom  of  the  chart.  Thus,  the  relative  and  compara- 
ble ages  among  the  lithologic  groups  are  indicated  as  closely  as 
possible — rocks  of  approximately  the  same  age  being  shown  on 
the  same  horizontal  level  in  the  legend.  The  marine  and  nonma- 
rine  (continental)  facies  of  the  Cenozoic  sedimentary  rocks  have 
also  been  distinguished. 

The  Cenozoic  rocks,  ranging  in  age  from  Holocene  through 
Paleocene,  have  been  grouped  into:  ( I )  marine  sedimentary 
rocks,  (2)  nonmarine  (continental)  sedimentary  rocks,  (3)  vol- 
canic rocks,  and  (4)  plutonic  rocks.  The  nonmarine  sedimentary 
rocks  are  distinguished  from  the  marine  rocks  by  the  letter  "c" — 
for  example,  "Pc"  for  Pliocene  "continental"  rocks.  The  Ceno- 
zoic volcanic  rocks  have  been  further  subdivided  into  fiow  rocks 
and  pyroclastic  rocks,  the  pyroclastic  rocks  being  distinguished 
by  the  superscript  "p." 

The  lower  half  of  the  Geologic  Legend,  representing  the  pre- 
Cenozoic  rocks,  is  more  complex  and  includes  rocks  of  Precam- 
brian  through  Mesozoic  age.  These  are  grouped  into:  ( 1 )  marine 
sedimentary  and  metasedimentary  rocks,  (2)  mixed  rocks  (of 
uncertain  age,  consisting  of  undivided  granitic  and  metamorphic 
rocks  or  undivided  metasedimentry  and  metavolcanic  rocks), 
(3)  metavolcanic  rocks,  and  (4)  plutonic  rocks. 

The  plutonic  rocks  are  classified  by  age  and  by  broad  litholog- 
ic types.  For  example,  the  granitic  types  are  the  most  common 
in  California  and  are  the  most  amenable  to  classification  by  age 
(mainly  on  the  basis  of  radiometric  data).  Among  the  granitic 
rocks,  the  Mesozoic  ones  have  the  greatest  extent,  but  Precam- 
brian.  Paleozoic,  and  Cenozoic  granitic  rocks  are  also  distin- 
guished. These  are  all  identified  by  the  symbol  "gr"  indicating 
their  basic  composition,  and  the  superscripts  Mz,  pG,  Pz,  and  Cz 
are  used  to  indicate  their  age.  Other  major  plutonic  types  are 
separately  identified  but  not  subdivided  in  detail.  For  example, 
the  ultramafic  rocks  (mostly  serpentine)  are  shown  as  "um"  and 


1<)85 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


59 


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DIVISION  OF  MINES  AND  GEOLOGY 


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TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


61 


gabbroic  rocks  as  "gb."  The  ultramafic  rocks  in  large  part  are 
fragments  of  mantle  material  of  various  ages  and  rest  in  their 
present  position  by  tectonic  rather  than  by  magmatic  processes. 

Rocks  of  the  Franciscan  Complex  have  been  separated  into 
three  subdivisions.  "KJf"  is  the  most  widespread,  and  consists 
of  Cretaceous  and  Jurassic  sandstones  with  smaller  amounts  of 
shale,  chert,  limestone,  and  conglomerate.  "KJf„"  indicates 
Franciscan  rocks  that  have  been  intensely  fragmented  and 
sheared  into  a  melange .  "KJf,"  is  the  designation  for  the  meta- 
morphosed part  of  the  Franciscan  Complex,  consisting  largely  of 
blueschist  and  semi-schist. 

A  hybrid  symbol  "SO"  is  used  for  Silurian  and  Ordovician 
rocks.  These  rocks  are  found  in  California  in  limited  extent  and 
could  not  be  readily  portrayed  on  the  present  map  if  shown 
separately.  The  rocks  occur  in  narrow  bands  in  the  Klamath 
Mountains,  Sierra  Nevada,  and  Basin  Ranges  geologic  prov- 
inces. 

Because  in  many  places  in  California  the  older  rocks  are  de- 
void of  fossils  (or  the  forms  found  may  not  be  complete  enough 
or  diagnostic  of  age),  several  broad  rock  groups  have  been  desig- 
nated for  some  of  the  pre-Cenozoic  rocks.  For  example,  the 
symbols  "m,"  "mv,"  "gr-m,"  "sch,"  and  "Is"  have  been  used  for 
rocks  whose  ages  are  very  uncertain.  The  symbol  "m"  is  used  for 
undivided  pre-Cenozoic  metasedimentary  and  metavolcanic 
rocks;  "mv"  for  undivided  pre-Cenozoic  metavolcanic  rocks; 
"gr-m"  for  a  mixture  of  granitic  and  metamorphic  rocks  ranging 
in  age  from  Mesozoic  to  Precambrian;  "sch"  for  schist  that  is 
believed  to  be  mostly  Paleozoic  or  Mesozoic  (although  some 
may  be  Precambrian);  and  "Is"  for  hmestone,  dolomite,  and 
marble  of  various  pre-Tertiary  periods  or  of  uncertain  age. 

A  similar  broad  rock  unit  group  has  also  been  used  in  one 
instance  in  the  Cenozoic  section.  This  is  the  symbol  "Tc,"  which 
is  used  to  represent  nonmarine  sedimentary  rocks  whose  relative 
age  cannot  be  determined  any  closer  than  Tertiary. 

Special  problems  exist  in  the  Cenozoic  rocks  where  it  is  impor- 
tant to  separate  the  nonmarine  from  the  marine  sedimentary 
rocks.  The  marine  Tertiary  rocks  lie  principally  along  the  west- 
em  part  of  the  state  (coastal  ranges).  However,  in  many  places 
within  sections  of  shallow-water  marine  rocks,  there  are  nonma- 
rine strata — for  example,  rocks  containing  coal  or  hgnite,  red 
beds,  and  sand  dunes.  These  are  not  shown  as  nonmarine  units 
if  they  appear  to  be  very  local  or  limited  in  area.  Likewise,  many 
elevated  marine  terraces  are  covered  wholly  or  in  part  by  a  thin 
cover  of  nonmarine  talus  debris.  These  areas  also  are  generally 
shown  as  marine  to  emphasize  the  geomorphic  origin  of  the  unit. 
Similarly,  a  unit  like  the  Sespe  Formation,  which  consists 
predominantly  of  red  beds  and  other  nonmarine  deposits,  does 
have  marine  facies — particularly  as  the  unit  is  traced  westward 
toward  the  sea.  The  Sespe,  in  addition,  poses  a  problem  because 
its  age  ranges  from  late  Eocene  to  early  Miocene.  In  portraying 
this  unit,  a  compromise  has  been  chosen,  and  the  unit  is  shown 
on  the  map  by  its  predominant  characteristics — nonmarine 
Oligocene. 

Among  the  older  (pre-Cenozoic)  rocks,  the  nonmarine  facies 
are  usually  almost  impossible  to  recognize  as  mappable  units  and 
have  only  been  done  so  in  a  few  places  in  California.  For  exam- 
ple, the  Cretaceous  Trabuco  Formation  and  the  Carboniferous 
Supai  Formation  have  been  recognized  as  being  wholly  or  in  part 
of  nonmanne  origin.  However,  these  rocks  are  exposed  only  in 
limited  areas  in  California,  and  are  hence  grouped  on  the  1:750,- 
000  scale  map  with  the  marine  units. 

Metamorphic  rocks  were  the  most  diPTicult  to  denote  on  the 
Geologic  Map  of  California.  In  general,  the  older  rocks  show 
increased  evidence  of  metamorphism,  although  this  might  be  of 
a  very  low  grade.  Where  the  age  of  metasedimentary  rocks  is 
known,  for  example,  by  their  fossil  content  or  by  well-defined 


stratigraphic  position,  the  unit  is  depicted  on  the  map  by  the 
symbol  representing  the  geologic  period  when  it  was  deposited. 
If  the  age  of  a  metamorphic  rock  unit  is  uncertain  or  unknown, 
we  tried  to  show  the  rocks  by  their  characteristic  field  appear- 
ance, for  example,  "sch"  (schist  of  various  types)  or  "Is"  (mar- 
bleized  limestone  or  dolomite).  Where  undivided  pre-Cenozoic 
metamorphic  rocks  have  not  been  mapped  by  their  metamorphic 
characteristics,  they  are  shown  on  the  compilation  simply  as 
"m"  (undivided  metasedimentary  and  metavolcanic  rocks),  or 
"mv"  (metavolcanic  rocks).  Where  the  general  age  of  some 
metasedimentary  and  metavolcanic  rocks  is  known,  the  symbols 
"Pz,"  "Mzv,"  and  "Pzv"  are  used  to  indicate  Paleozoic 
metasedimentary  rocks  and  Mesozoic  and  Paleozoic  metavol- 
canic rocks. 

The  map  legend  also  shows  that  the  Geologic  Map  of  Califor- 
nia tends  to  emphasize  bedrock  rather  than  surficial  geologic 
units.  It  can  be  seen,  however,  that  various  surficial  deposits  of 
Quaternary  age  are  lumped  into  the  unit  "Q."  The  largest  area 
of  such  surficial  deposits  in  the  state  is  the  Great  Valley  of 
California.  Smaller  deposits  occur  elsewhere,  but  they  are  usu- 
ally shown  only  where  the  area  covered  is  significant.  Stream 
alluvium,  fan  deposits,  salt  deposits.  Quaternary  lake  deposits, 
and  Quaternary  marine  or  stream  terrace  deposits  are  all  includ- 
ed in  the  unit  "Q."  Such  deposits,  however,  are  not  shown  if  they 
greatly  interfere  in  the  depiction  of  the  bedrock  units.  An  excep- 
tion to  this  general  rule  is  the  case  where  a  fault  intersects  or 
offsets  Quaternary  surficial  units.  In  such  cases,  the  young  surfi- 
cial unit  might  even  be  exaggerated  to  illustrate  this  important 
evidence  for  recency  of  faulting. 

Certain  other  Quaternary  surficial  deposits  are  shown  where 
significantly  large.  For  example,  glacial  deposits  are  shown  be- 
cause of  their  importance  to  Quaternary  chronology,  and  exten- 
sive dune  sand  deposits  are  depicted,  especially  where  they  occur 
as  rather  large  areas  of  possible  economic  or  geomorphological 
importance.  Lastly,  some  Quaternary  landslide  deposits  are  in- 
dicated where  they  are  particularly  large  (for  example,  Black- 
hawk  and  Martinez  Mountain  rock  slides  in  southern 
California),  or  where  they  drastically  obscure  the  geologic  rela- 
tionships of  the  bedrock  units  (for  example.  Table  Mountain 
serpentine  landslides  in  the  central  Coast  Ranges).  Unfortunate- 
ly, the  decision  to  show  landslide  deposits  was  not  made  until  the 
compilation  was  well  underway;  as  a  result,  some  truly  huge 
landslides  have  not  been  depicted.  This  is  not  altogether  a  short- 
coming of  the  map,  however,  because  if  too  many  large  land- 
slides were  shown,  the  bedrock  geology  would  be 
correspondingly  obscured. 


Colors,  Patterns,  Symbols  of  Rock  Units, 
and  Map  Appearance 

A  combination  of  colors,  patterns,  and  symbols  has  been  used 
to  distinguish  the  rock  units  shown  on  the  Geologic  Map  of 
California.  Each  device  was  chosen  to  adhere  as  closely  as  possi- 
ble to  national  or  international  convention  and  to  best  illustrate 
the  complex  geology  of  California. 

I .  Colors:  Worldwide  efforts  to  achieve  a  systematic  scheme 
of  colors  for  geologic  maps  began  nearly  a  century  ago.  The  2nd 
and  3rd  International  Geological  Congresses  made  recommen- 
dations for  international  standards  in  1881  and  1885,  and  the 
World  Map  Commission  made  certain  modifications  in  1958.  In 
this  country,  attempts  to  set  a  national  standard  of  colors  for 
portraying  rocks  of  each  geologic  age  began  in  1881  with  J.W. 


62 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


GEOLOGIC 


MARINE  SEDIMENTARY  ROCKS 


NONMARINE  (CONTINENTAL)  SEDIMENTARY  ROCKS 


• 

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Earentivs  mariiM  ond  nonmorin*  tond  depoiiM.  ^n»iaiiy 
neor  Hm  cooil  or  d«t«r1  ployot. 


Selected  large  londtlidet,  iwch  oi  Blockhawk  Slide  on 
rtortti  tide  of  Son  Gabriel  Mountaini;  eoHy  lo  loie  Quoter- 
fKjry. 


m 


Alluvium,  lake,  playa,  ond  lerroce  depotili;  unconiolidot- 
ed  ond  iemi-conu>lidated  MatHy  nonmanne.  but  includei 
morine  depOfili  neor  fhe  cooil 


Glocial  till  and  morainei.  Found  af  high  elevations  moitly 
in  the  Sierra  N*vodo  ortd  Klomoth  Mowntaint. 


Sondilone,  lilhtone,  thole,   and  conglomerote;  moilly  moderately  con- 
solidated. 


Sandilorte,  thole,  liltitone,  conglomefote,  and  breccia;  moderately  to  well 
consolidated. 

Sandstone,  shole.  conglomerate;  mostly  well  consolidated 


Shale,  sandstone,  cortgtomerate,  minor  limeslorte;  moitly  well  consolidoted. 


Sandstone,  shole,  and  conglomerate;  motlty  well  consolidated. 


Pliocerte  ond/or  Pleislocene  sandstone,  shole.  and  grovel  depos- 
its; moitly  loosely  consolidated. 


Sor^storte,  shale,  conglomerate,  and  fonglomerote;  moderately 
lo  well  consolidated. 


Undivided  Tertiary  sarsdslone.  shole,  conglomerote.  brec- 
cia, ortd  artcient  lake  deposits. 


Sortdslone,  shole.  and  conglomerate;  mostly  well  consolidoted. 


Sandstone,  shale,  conglomerote;  moderately  to  well  consolidat- 


MARINE  SEDIMENTARY  AND  METASEDIMENTARY  ROCKS 


ia    s 


5      i 


Sor>dstone,  shole.  ar»d  mirsor  conglomerate  in  coastal  belt  of  nortSweilem 
California;  included  by  sottm  in  FrorKiscan  Complei.  Previously  considered 
Cretoceows,  but  rvow  krtown  to  contoin  eorly  Tertiory  microfossils  in  ploces. 


Upper  Cretoceout  landitone,  shale,  artd  conglomerate. 


Lower  Cretoceou*  Mindifone,  ihale,  and  conglomerate. 


Shale,  sandilo«>e.  minor  conglomerate,  chert,  slate,  limeslorte;  minor  pyro- 
cloitk  rock*. 


Shole.  cor>glomerote,  limestone  and  dolomite,  sandstone,  slate,  homfels, 
quorttite;  minor  pyroclostic  rocks. 


r:^ 


Shale,  cor>glomerole.  limestone  and  dolomite,  sandstone,  ilote,  homfels, 
quortiite;  minor  pyroclostic  rocks. 


Shole.  sartdslone,  conglomerate,  limestone,  dolomite,  chert,  homfels,  mar- 
ble, quartiile;  m  part  pyroclostic  rocks. 


Limestone  or>d  dolomite,  sandstone  and  shole;  in  port  tuffoceous 


Sondstor>e.  shale,  conglomerore,  chert,  slate,  quortiite,  homfels,  marble, 
dolomite,  phylltte;  some  greenstorte. 


SortditoTM,     shale,     limestone,     dolomite,     chert,    quortiite.  ond  phyllite; 
includes  some  rocks  thot  ore  possibly  Precambrian. 


Conglomerote.  shole,  sandstone.  limestor>e.  dolomite,  marble,  gneiss,  hom- 
fels. ond  qworttite;  moy  be  Poleoioic  in  port 


Undivided  Cretoceovt  iar»dstor>e,  shale,  and  cor»- 
glomerate;  miiKM  nonmarirre  rocks  in  Peninsular 
Ranges. 


Kjr:  FrarKiKon  Complex:  Cretaceous  and  Jurassic  sandstorte  with 
smolter  amounts  of  shale,  chert.  timestof\e,  orvd  cor>glomerote 
Includes  FrarKiscon  melange,  except  where  seporated-see  KJf,. 

Kji«:  Mdongeof  frog  men  ted  and  sheared  FroncisconComplex  rocks. 

Kji,  :  BIweschisi  and  semi-schist  of  FrorKiscan  Complex. 


Schists  of  various  types;  mostly  Poleoioic  or  Meso- 
loic  oge;  some  Precombrian. 


Limeitorte.  dolomite.  ar»d  morble  whose  oge  ii  un- 
certoin  but  probobly  Poleoioic  or  Mesotoic 


Undivided  Poleoioic  metosedimentory  rocks  In- 
cludes slote.  sar>dstone.  shale,  chert,  conglomerate, 
limestone,  dolomite,  morble,  phylltte,  schist,  hom- 
lels.  and  quortiite. 


Figure  15.      Geologic  Legend   (generalized  description  of  rock  types) 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


63 


LEGEND 


\  OLCANIC  ROCKS 


PLUTONIC  ROCKS 


0..  a 


0>:    R«c«At  (Holocan*)  ■dconk  flow  tocki;  nMwr 

pyrodoftk  dapoiiti 
(>■*:  t«c««l    (Holocana)    pyrodoitk   and    loiconk 

mudflow   6*poun. 


a,' 


dcpotiH. 
Ov* :     Q\iat**norf  pyrodoiHc  and  vokonk  mvdflow 
dvpoftv 


Tv :      Tsrtiofy  volcomc  flow  rockt;  minor  pyrodaiHc 

<l*pOtitl. 
r.»i     T«ft»ory  pyroclaihc  of>d  vokontc  mudflow 
dvpoiitt. 


Tvftiory    mtrvvv*    rocki;  moitty    ihoNow     (hypobytiol) 
plugi  and  dikvi. 


OH^ 


C«nozo*C  (Tertiary)  Qronilic  rock* — quartz  monxo- 
nile,  qwortz  lotit*,  ond  minor  monzonlte,  orar>odior- 
it«,  ar>d  gronitv;  found  m  ttte  Kingilon,  Ponomint. 
AmorgoMi.  and  G'e*nwot»r  Ror>oet  in  K>urt>«Oit- 
em  Cal'pfomta 


MIXED  ROCKS 


META\OLCANlC  ROCKS 


PLUTONIC  ROCKS 


GroniHc  and  NMtamorpluc  rocks,  mosriy  gn«iu  and 
oftwr  rwtamorphk  rockl  iniected  by  gronitic  rockv 
MeioioK  h)  pTtcomhnan, 


Undnnd*d  pre-Csrtozoic  mctascdi  men  lory  ond 
m«tovolcan>c  rocki  o4  grval  vonety  Moitty  Uote. 
qwartiii*.  Komfeli.  chert,  phyllite.  myionil*.  icKiit, 
gr>*<ii,  ond  minor  morbU. 


oO: 


CompU*  of  Precombrion  igneout  ortd  mclomorphK 
rockL  Mottly  gn*>u  and  Khiil  intruded  by  igrkeoMt 
rockij  noy  be  Mvtoxok  in  port. 


Uf 


Urtdivided  Metoioic  volconic  or»d  metovokonic 
rockt  Andeiile  and  r+iyoJit«  Bow  rocki.  greenilone, 
TolconK  breccia  ond  other  pyrockjltic  rocki;  in  port 
itrongfy  melomorphoied  Includei  vokonic  rocki  of 
Fronc'Kon  Complei-  boMiltic  pillow  lovo,  diaboie, 
greenitorte.  artd  mir>or  pyrocloitic  rocki. 


Undnrided  pre-Cenozok  metovolconic  rocki.  ln< 
cli>dei  latite,  docite.  twtf.  and  greenstone;  common- 
ly   KhiltOM 


Ufxlivided  Paleozoic  metovokonic  rockt  Moitly 
fkiwi.  breccia,  and  tuM.  irKluding  greenstone,  dio- 
boM  ond  pilow  lovQi;  minor  mterbedded  ledimert- 


Mesozok  granite,  quortz  monzonite,  granodiorite, 

ond  quart!  dionte 


Ultromofk  rockl.  mottty  Mrpentirte.  Mirtor  pendo- 
tite.  gobbro,  ond  diobai*    Otieffy  Metotok 


Gabbro  artd  dork  (fioritk  rocki;  chiefly  Mewzok. 


Undated  gronitk  rocki. 


Paleozok  ond  Permo-Trioiiic  gronitk  rockt  in  the 
Son  Gabriel  ond  Klamath  Mountomt. 


Precombnon  gronde.  tyer^ite.  orvorthotile.  artd 
gobbroK  rockt  m  Itte  Son  Gobnel  Mountomt.  atio 
vorioui  Precombnon  pKttonk  rockt  eliewhere  tn 
towtheottem  CoTifomio. 


64 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Table  11.      Comparison  of  "American"  and  "International"  map  colors  for  sedimentary  rocks. 


SYSTEM 

AMERICAN  COLOR  SYSTEM 

INTERNATIONAL  COLOR  SYSTEM 

U.S.  GEOL.  SURVEY 
2nd  ANN.  REPT. 
1881' 

GEOLOGIC  MAP  OF 
UNITED  STATES 
1974^ 

GEOLOGIC  MAP 
OF   CALIFORNIA 
1977  ' 

2nd  and  3rd 

INTERNAT.  GEOL.  CONG. 
BOLOGNA  AND  BERLIN 
1881,  1885' 

WORLD   MAP 

COMMISSION 

1959' 

QUATERNARY 

Gray 

Gray 
Pole  yellow 

Pah  yalhw 
Gray 

Undecided 

Pate  yellow  brown 

TERTIARY 

Yello. 

Yellow 

Pole  brown 

Pole  flesh 

Dorit  yellow 

Greenish  yellow 

Oronge 

DeHcyeOow 

f/eth 

Ton 

Greenith  yellow 

Yellow  green 

Yellow 

Shodes  of  yellow 

CRETACEOUS 

Green 

Olive  green 
Yellow  green 
Cool  green 

Ofive  green 
Coal  green 
Gray  green 

Green 

Light  greeni 

JURASSIC 

Blue  green 

She  green 

Blue 

Shades  of  blue 

TRIASSIC 

Peacock  blue 

Peacock  blue 

Violer 

Ughl  purple 

PERMIAN 

Blue 

Cool  bloe 

Cool  blue 

Gray 

Warm  brown 

PENNSYIVANIAN 

Gray 

Warm  blue 

Dork  groy 

MISSISSIPPIAN 

Worm  blue 

DEVONIAN 

Purple 

Blue 

Dofi  blue 

Brown 

Brown 

SILURIAN 

Purple 

Lavender 

Greeniih  gray 

Grayish  green 

ORDOVICIAN 

Rose  and  pink 

Medium  green 

CAMBRIAN 

Red  and  coral 

Dark  lavender 

Brownish  green 

PRECAMBRIAN 

Bro.n 

Yellow  brown 

Brown 

Bluish  gray 

Brick  red 

Worm  brown 

Rose 

Groyish  green 

ro 

Orange  pink 

and  Rose 

'    Powell.  1882.  p.  xi-iv 
*   Jennings.  1977 


'    King  and  Beikman.  1974 

*     King  and  Beikman.  1974.  p.  27;  also  see  Fraser,  1888.  p.  90 


*   Commission  for  the  Geologic  Map  of  ihe  World.  1959 


Table  12.       Comparison  of  "American"  and  "International"  map  colors  for  plutonic  and  volcanic  rocks. 


AMERICAN  COLOR  SYSTEM 

INTERNATIONAL  COLOR  SYSTEM 

ROCK  TYPE 

U.S.    GEOL.  SURVEY 
2nd  ANN.  REPORT 
1881' 

GEOLOGIC  MAP  OF 
THE  UNITED  STATES 
1974^ 

GEOiOClC  MAP  OF 

CALIFORNIA 

1977^ 

2nd  and  3rd 

INTERNAT.  GEOL.  CONG. 
BOLOGNA  AND  BERLIN 
1881,  1885' 

WORLD  MAP 

COMMISSION 

1959' 

u 
z 
O 

t- 

3 

Q. 

"Granitic" 

-o 

« 

o 

s 

-D 
O 

Rondom  dash-portern 
on  color  ossigned  to 
sedimentory  rocks  of 
same  age 

Shades  of  red 

■D 

V 

O 

c 

c 
« 

Shades  of  bright 
red  to  bright  red 
oronge 

Mofic 

Double  dosh-pattern 
on  shades  of  green 
[Jurassic  and  Paleozoic) - 
Solid  pale  red    (Triassrc)  . 

0 

Light  purple 

Shades  of  purple 

Ultramafic 

Dork  blue 

III 

Dark  purple 

U 

z 
< 

Cenozoic 
Volconic 
Rocks 

Shades  of  pink  and 
orange   Ifelsic  rocks 
with  v-pottern  ] 

6  «, 

Orange 

Shades  of  strong 
oronge   (acid)   to 
purplish  reds  (basic) 

1 

Pink 

1 

Salmon 

Pre-Cenozoic 

Volconic 

Rocks 

v-pottern  on  color 
assigned  to  sedimentary 
rocks  of  same  age- 

v-pattern  on  color 
oisigned  to  iedimentary 
rocks  of  iome  age 

Pattern  of  short 
lines  on  color 
osjigned  to  sedimentary 
rocks  of  some  age. 

'  Powell.  1882.  p   Xi'lv 
'  King  and  Beikman.  1974 


'  Jennings.  1977 
"  Fraser.  1888.  p  95 


*  Commission  for  the  Geologic  Map  of  the  World.  1959 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


65 


Powell,  Director  of  the  U.S.  Geological  Survey.  For  an  interest- 
ing history  of  the  development  of  schemes  for  geologic  map 
colors,  the  reader  is  referred  to  King  and  Beikman  (1974,  p. 
25-28). 

Both  schemes  proposed  that  the  orderly  sequence  of  sedimen- 
tary rock  units  be  portrayed  on  geologic  maps  by  a  prismatic 
sequence  of  colors.  For  example,  with  the  use  of  yellow,  green, 
blue,  and  violet,  yellow  would  be  younger  than  green,  green 
younger  than  blue,  and  so  forth — the  darker  shades  representing 
progressively  older  rocks  (Table  11).  In  this  way,  the  map  would 
show  at  a  glance  which  sedimentary  rocks  were  younger  and 
which  were  older,  and  oftentimes,  the  structures  they  form 
would  be  readily  apparent. 

In  actual  practice,  most  geologic  maps  follow  this  principle 
but  with  departures  because  of  limitations  in  contrasting  shades 
of  color  for  areas  with  numerous  units  of  comparable  ages.  The 
"International  color  system"  works  well  for  maps  of  Europe 
(where  the  system  was  proposed),  but  it  has  important  deficien- 
cies for  geologic  maps  of  the  United  States.  The  international 
scheme,  unfortunately,  is  not  entirely  suitable  for  areas  where 
Paleozoic  and  Precambrian  rocks  predominate  and  where  they 
have  been  subdivided  into  numerous  periods.  This  was  not  a 
problem  in  Europe  where  neither  the  Precambrian  nor  the  Paleo- 
zoic is  extensive  or  subdivided  as  much  as  in  some  other  parts 
of  the  world. 

Therefore  the  map  colors  proposed  by  Powell,  with  subse- 
quent elaborations,  have  become  the  "American  color  system," 
which  is  the  general  model  used  by  the  U.S.  Geological  Survey. 
The  principal  differences  between  the  "American"  and  "Interna- 
tional" color  systems  are  shown  in  Table  1 1  for  the  sedimentary 
rocks  and  Table  12  for  the  igneous  rocks.  Note  that  in  the' Ameri- 
can" system  the  blues  and  shades  of  purple  extend  farther  down 
in  the  Paleozoic  Era,  and  also  note  the  different  treatment  of  the 
intrusive  and  extrusive  rocks. 

The  color  scheme  chosen  for  the  Geologic  Map  of  California 
is  largely  patterned  after  the  "American"  system,  as  exemplified 
by  the  U.S.  Geological  Survey's  Geologic  Map  of  the  United 
States  (King  and  Beikman,  1974)  for  the  sedimentary  rocks,  but 
a  closer  adherence  to  the  "International  color  system"  was  fol- 
lowed for  plutonic  and  volcanic  rocks.  Note  that  bright  reds  and 
purples  have  been  reserved  on  the  California  map  for  plutonic 
rocks.  This  departure  from  the  "American"  system  is  in  keeping 
with  a  long  tradition  of  geologic  maps  of  California.  The  use  of 
bright  colors  for  the  plutonic  rocks  achieves  a  much  better  con- 
trast between  the  vastly  different  sedimentary  and  plutonic  rock 
types.  A  glance  at  the  Geologic  Map  of  California  and  the  bright 
red  color  immediately  conveys  the  location  of  batholithic  rocks, 
and  the  deep  purple  color  shows  the  distribution  of  serpentinite 
and  related  ultramafic  rocks,  which  are  so  important  tectonically 
and  economically  to  California.  Following  the  use  of  intense  red 
for  the  deep-seated  plutonic  rocks,  warm  shades  of  pink  and 
orange  are  used  to  portray  volcanic  rocks. 

Among  the  prismatic  colors  used  to  portray  sedimentary 
rocks,  there  is  not  a  large  contrast  between  the  yellowish-greens 
of  the  Lower  Tertiary  rocks  and  the  light  green  of  the  Upper 
Cretaceous  rocks.  This  was  done  purposely,  because  in  many 
places  in  California  the  distinction  between  rocks  of  these  ages 
is  very  difficult  to  draw.  Lithologically,  the  rocks  of  these  two 
ages  are  commonly  identical,  and  the  lack  or  sparseness  of  fossils 
makes  the  separation  in  many  cases  almost  impossible. 

A  similar  situation  exists  with  the  "coastal  belt"  rocks  of 
northwestern  California,  shown  as  "TK."  These  rocks  of  li- 
thologic  similarity*  to  the  Franciscan  Complex  (indeed,  often 

*  Cottstal  belt  rocks,  when  analyzed  carefully,  often  have  a  high  K-feldspar  content, 
unlike  the  typical  Franciscan  rocks. 


shown  as  Franciscan  on  some  maps)  are  now  known  to  contain, 
in  the  sparse  fossil  record,  early  Tertiary  microfossils.  Hence, 
these  rocks,  too,  are  shown  as  a  transitional  green  between  the 
Lower  Tertiary  and  Upper  Cretaceous  colors.  Likewise,  lithol- 
ogy  and  other  characteristics  of  Miocene  and  Oligocene  marine 
sedimentary  rocks  are  often  very  close  and  hence  are  portrayed 
by  similar  colors  on  the  map. 

2.  Patterns:  In  addition  to  colors,  certain  rock  units  are  distin- 
guished by  an  overprint  pattern  (Table  13).  Basically,  all  marine 
sedimentary  or  metasedimentary  units,  whether  Cenozoic, 
Mesozoic,  Paleozoic,  or  Precambrian,  are  represented  by  solid 
colors  without  any  overprint  patterns.  Nonmarine  units  (distin- 
guished on  this  map  in  the  Cenozoic  only)  are  shown  by  the 
same  color  that  is  used  to  show  their  marine  counterparts,  but 
with  a  stipple  pattern  overprint  (either  blue  or  red,  depending 
on  which  shows  up  better). 

Table  13.      Patterns  used  on  Geologic  Map  of  California. 


UNIT 

PATTERN 

Nonmarine  sedimentary 
rocks  (Distinguished 
only  in  Cenozoic) 

Stipple  pattern  on  same  solid 
color  as  marine  counterparts. 

Marine  sedimentary  rocks 
(all  ages) 

No  pattern,  solid  colors  represent  - 
ing  appropriate  geologic  age. 

Pyroclastic  volcanic 
rocks  (Cenozoic  age 
only) 

V-pattern.  on  appropriate  strati  - 
graphic  color. 

Metavolcanic  rocks 
(Pre-Cenozoic  age) 

V-pattern.  on  appropriate  strati  - 
graphic  color. 

Franciscan  melange 
(where  mapped) 

Random  dot  pattern  on  green 
color  of  Franciscan  Complex  rocks. 

Highly  metamorphosed 
rocks  (schist,  gneiss, 
slate,  mylonlte.  etc.) 

Randomly  oriented  short  dashes. 

Granitic  rocks 

Red  color  with  various  patterns  to 
distinguish  various  ages. 

Pyroclastic  volcanic  rocks  of  Cenozoic  age  and  metavolcanic 
rocks  of  pre-Cenozoic  age  are  shown  with  a  v-pattem  overprint 
on  the  appropriate  stratigraphic  color. 

A  random  dot  pattern  overprint  is  used  on  the  green  color  of 
the  Franciscan  Complex  to  indicate  where  areas  of  melange  have 
been  mapped.  Because  melange  in  the  Franciscan  has  been 
recognized  as  mappable  units  only  in  the  past  decade,  this  infor- 
mation is  incomplete.  However,  because  of  its  importance  to 
structural  concepts  and  its  relevance  to  the  stability  of  slopes, 
this  information  is  shown  where  it  is  known  (although  often 
without  contacts  bounding  the  unit  and  with  only  the  pattern  to 
indicate  the  presence  of  mapped  melange). 

Most  of  the  more  highly  metamorphosed  rocks  (for  example, 
schist,  gneiss,  slate,  mylonite,  etc.)  and  the  undivided  mixed 
rocks  are  shown  with  an  overprint  of  randomly  oriented  short 
dashes.  Granitic  rocks  of  different  ages  are  depicted  with  various 
distinguishing  overprint  patterns. 

3.  Symbols:  Besides  colors  and  patterns,  each  geologic  unit  is 
identified  by  a  letter  or  combination  of  letters  in  order  to  aid  in 
matching  the  colors  of  map  units  to  units  with  similar  colors  on 
the  legend.  This  is  particularly  helpful  in  complex  parts  of  the 
map  where  the  unit  may  only  be  a  small  patch  or  a  narrow  band. 


66 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Symbols  become  increasingly  useful  as  the  map  fades  with  time 
and  makes  some  color  contrasts  more  difficult  to  distinguish.  We 
have  also  found  it  particularly  useful  to  label  every  area  bounded 
by  contacts  with  a  symbol  because  it  enables  the  pubhcation  of 
an  uncolored  edition  of  the  geologic  map. 

The  letter  symbols  used  on  the  Geologic  Map  of  California 
were  chosen  to  comply  as  much  as  possible  with  accepted  con- 
ventions, and  also  to  be  simple.  Most  symbols  consist  of  a  single 
capital  letter  indicating  the  geologic  epoch  or  period  when  the 
rock  tormation  was  formed.  In  some  cases,  combinations  of 
capital  letters  were  used  where  the  age  of  the  unit  widely  trans- 
gresses geologic  time,  for  example,  "TK"  for  Tertiary-Cretaceous 
rocks.  Likewise,  "SO"  was  used  for  Silurian  and  Ordovician 
rocks,  which  because  of  their  limited  exposure  in  California, 
would  not  have  shown  up  individually. 

Because  of  the  repetition  of  certain  first-letters  in  the  names 
of  several  periods  and  epochs,  a  number  of  contrived  symbols 
were  utilized.  For  example.  Pliocene,  Paleocene,  Permian,  and 
Paleozoic,  each  begin  with  the  letter  "P";  therefore,  the  follow- 
ing symbols  were  used  for  these  units  respectively;  P,  Ep,  Pm,  and 
Pz.  This  follows  the  convention  used  for  many  years  on  the 
Geologic  Atlas  of  California  and  on  some  U.S.  Geological  Sur- 
vey maps.  Cenozoic,  Cretaceous,  Carboniferous,  and  Cambrian 
also  posed  a  problem  with  the  repetition  of  the  first  letter  "C." 
This  was  resolved  by  using  the  symbols  Cz,  K,  C,  and  €.  This 
has  also  been  common  practice  on  Califomian,  U.S.  Geological 
Survey,  and  a  number  of  foreign  geologic  maps  for  many  years. 

Lower  case  "u"  and  "1"  differentiate  upper  and  lower  parts  of 
certain  periods,  for  example,  Ku  and  Kl.  Lower  case  "c"  identi- 
fies nonmarine  ("continental")  sedimentary  rocks.  A  lower  case 
"v"  is  used  to  denote  volcanic  rocks,  and  a  superscript  "p"  is 
used  to  distinguish  Cenozoic  volcanic  rocks  of  pyroclastic  origin 
from  flow  rocks.  Other  lower  case  modifiers  used  are;  "g"  for 
Quaternary  glacial  deposits  (Qg),  "i"  for  Tertiary  intrusive 
rocks  (Ti),  and  "s"  for  extensive  Quaternary  sand  deposits 
(Qs). 

For  plutonic  and  metamorphic  rocks  that  range  widely  in  age 
or  are  of  uncertain  age,  lower  case  letters  or  combinations  of 
letters  are  used  to  indicate  their  broad  rock  classification.  For 
example,  "m"  is  used  for  undivided  pre-Cenozoic  metamorphic 
rocks  (where  metasedimentary  and  metavolcanic  rocks  have  not 
been  distinguished);  "mv"  for  metavolcanic  rocks;  "sch"  for 
schist;  "Is"  for  hmestone,  dolomite,  and  marble;  "gr"  for  granitic 
rocks;  "gb"  for  gabbro;  and  "urn"  for  ultramafic  rocks  (mostly 
serpentmite  and  related  rocks). 

4.  Map  appearance:  It  is  apparent,  even  from  a  distance,  that 
the  Geologic  Map  of  California  shows  a  major  color  contrast 
among  certain  geologic  units.  This  was  purposely  intended.  For 
example,  the  deep-seated  batholithic-type  rocks  shown  in  bright 
red  hues  are  easily  distinguished  from  the  paler  (pastel)  hues 
depicting  the  sedimentary  and  metasedimentary  rocks  (arranged 
in  a  prismatic  sequence,  yellows  through  lavender  with  the  dark- 
er colors  being  the  oldest).  Between  these  two  principal  color 
and  rock  contrasts  are  depicted  the  Cenozoic  volcanic  rocks, 
shown  in  shades  of  warm  pink  and  orange.  Thus,  at  a  glance,  the 
map  user  is  able  to  see  the  distribution  of  the  granitic  rocks,  the 
widespread  Cenozoic  volcanic  rocks,  the  sedimentary  and 
metasedimentary  rocks,  and  the  vast  basins  of  unconsolidated 
alluvium. 

On  closer  inspection,  with  attention  to  various  patterns  used, 
the  map-user  is  able  to  easily  differentiate  between  marine 
and  nonmarine  rocks  (stipple  pattern  on  the  latter);  most  vol- 
canic rocks  (random  v-pattem)  ;  and  metamorphic  rocks 
(randomly-oriented  dash  pattern). In  addition, stratified  rocks  of 
similar  age  and  lithologic  origin  appear  as  different  shades  of  the 


same  color.  In  this  way,  they  may  appear  as  one  unit  from  a 
distance  and  the  major  sedimentary  groups  are  emphasized; 
however  on  closer  inspection,  the  rock  groups  can  be  separated 
by  the  more  subtle  color  contrasts. 

Geologic  Time  Scale 

In  addition  to  the  conventional  geologic  legend  on  the  Geolog- 
ic Map  of  California,  in  the  lower  left-hand  part  of  the  map  is 
a  chart  portraying  a  generalized  geologic  time  scale.  This  chart 
is  reproduced  as  Table  14  (but  without  color). 

The  purpose  of  this  generalized  time  scale  is  to  assist  those 
who  are  not  familiar  with  the  geologist's  way  of  depicting  rela- 
tive rock  ages.  The  term  "relative  geologic  time"  is  used  on  the 
chart,  for  that  is  how  geologists  began  scores  of  years  ago  to 
depict  rock  sequences,  not  knowing  the  rock's  actual  age  in 
numbers  of  years.  Of  course,  with  the  knowledge  of  radioactive 
decay  rates  and  other  sophisticated  dating  techniques,  geologists 
now  can  determine  the  actual  age  of  many  types  of  rocks. 
However,  the  generalized  geologic  time  scale  was  devised  to  put 
rock  ages  in  some  sort  of  perspective,  especially  as  they  relate  to 
the  evolution  of  life  on  the  planet.  The  same  geologic  time  scale 
is  used  universally  by  all  geologists  and  paleontologists. 

The  generalized  time  scale  shown  on  the  Geologic  Map  of 
Cahfomia  is  shown  in  color  to  match  the  major  time  units  of  the 
stratified  rocks  depicted  on  the  map.  Subdivisions  of  the  various 
periods  are,  of  course,  shown  on  the  Geologic  Map  by  shades  of 
the  colors  shown  on  the  generalized  geologic  time  scale.  For 
example.  Upper  and  Lower  Cretaceous  are  shown  in  shades  of 
green,  and  subdivisions  of  the  Paleozoic  are  shown  in  shades  of 
blue  and  lavender. 

The  colored  time  scale  shows  that  the  colors  are  arranged  as 
a  spectrum  with  yellow  for  the  youngest  rocks,  green  for  Meso- 
zoic.and  blue  and  lavender  for  Paleozoic.  Thus,  the  map-user  can 
quickly  get  an  approximate  idea  of  the  distribution  and  age  of 
stratified  rocks  within  the  state. 

Volcanoes 

The  location  of  numerous  volcanoes  of  all  types  (cinder  cones, 
domes,  composite  or  stratovolcanoes)  are  shown  on  the  Geolog- 
ic Map  of  Cahfomia  with  the  conventional  volcano  symbol,  in 
the  same  way  that  they  are  shown  on  the  Fault  Map  of  Cahfor- 
nia.  Some  565  volcanoes  are  plotted,  most  of  which  are  cinder 
cones.  The  greatest  concentration  of  volcanoes  in  California  are 
in  the  Modoc  Lava  Plateau,  Clear  Lake,  Owens  Valley,  and 
certain  southern  California  desert  areas.  For  more  discussion  of 
volcanoes,  see  pages  43  -  45 . 

Batholiths  and  Plutons 

Numerous  granitic  intrusive  bodies  are  found  in  California, 
and  many  of  these  have  been  given  specific  names  as  they  are 
studied  in  detail.  Table  15  is  a  list  of  all  the  named  granitic 
intrusive  masses  shown  on  the  Geologic  Map  of  California,  1977 
edition.  Additional  plutons  have  been  carefully  studied  and 
named,  but  because  of  their  relatively  small  size  or  the  lack  of 
space  available  on  the  map,  they  are  not  labeled.  Others  have 
been  the  subjects  of  careful  study,  but  the  results  of  the  studies 
had  not  been  published  at  the  time  the  compilation  of  the  map 
was  under  way. 

The  term  hatholith  has  traditionally  been  used  for  large  plu- 
tonic bodies,  usually  of  granitic  composition,  that  generally 
cross-cut  the  structure  of  the  rock  they  intrude  and  have  steep 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


67 


Table  14.     Geologic  time  scale. 


RELATIVE  GEOLOGIC  TIME 


Epoch 


TIME 

in  millions  of 

years  before  present 


TIME  OF  APPEARANCE  0(^  DIFFERENT  FORMS  OF  LIFE 


Quaternary 


Tertiory 


Oligocene 


Cretaceou! 


Carboniferous 
Systems 


Siluric 


Precombrian 


225  - 
280  • 
320 
345  ■ 


4,500 


1  Historic  record  in  California,  200  years 
Post-glacial  period 


Ice  oge,  evolution  of  man. 


Age  of  mammotfts. 


Spreod  of  onlfiropoid  apes. 


Origin  of  more  modern  families  of  mammals,  grazing  animals. 


Origin  of  many  modern  families  of  mammals,  giont  mammals. 


Origin  of  most  orders  of  mammals,  early  fiorses. 


Appeoronce  of  flowering  plonts;  extinction  of  dinosaurs  at  end;  appearance  of  a  few  modern  orders  and 
fomilies  of  mammals. 


Appeoronce  of  some   modern  genera  of  conifers;   origin  of   mommols   and   birds;  fieigf>t  of  dinosaur 
evolution. 


Dominance  of  mommol-liko  reptiles. 


Appeoronce  of  modern  insect  orders. 


Dominance  of  omphiblans  and  of  primitive  tropical  forests  wfiich  formed  coal;  earliest  reptiles. 


Earliest  ompftibions. 


Earliest  seed  plonts;  rise  of  bony  fisfies. 


Earliest  land  plants. 


Earliest  known  vertebrates. 


Appeoronce  of  most  phyla  of  invertebrates. 


Origin  of  life;  olgae,  worm  burrows. 


Estimoted  age  of  earth. 


Modified  from  U  S.  G«olo9icol  Survey.  Geologic  r>Jamei  Commitlee,  1972,  and  G.  ledyord  Slebbins,  ProceHes  ol  organic  evolution,  1966,  Prenfice.Holt,  Inc.,  Englewood  CliKs.  New  Jersey 
•  11.000  yeofi,  Zlony  el  ol..  1974,  US  Geological  Survey  Mop  MF  585, 


walls  dipping  outward  so  that  the  body  enlarges  downward  and 
has  no  visible  or  inferred  floor.  Often  a  batholith  is  a  regionally 
extensive  complex  body,  consisting  of  many  individual  intrusive 
masses  of  various  compositions.  The  term  pJuton  is  a  noncom- 
mittal term  for  an  intrusive  igneous  body  of  any  shape  or  size. 
Also,  it  is  commonly  applied  to  the  various  separate  intrusive 
masses  that  make  up  a  batholith.  Stock  is  a  much  more  restric- 
tive term  for  an  intrusive  igneous  body  having  the  features  of  a 
batholith,  but  covering  less  than  40  square  miles  (100  km^). 

The  largest  of  the  batholilths  in  the  state  is  the  Sierra  Nevada 
batholith,  which  is  at  least  644  km  (400  miles)  long  and  as  much 
as  80-97  km  (50-60  miles)  wide.  Strictly  speaking,  the  Sierra 
Nevada  batholith  is  confined  to  the  granitic  terrane  of  the  Sierra 
Nevada  (Bateman  and  others,  1963),  and  it  is  labeled  this  way 
on  the  Geologic  Map  of  California.  However,  in  a  broader  sense 
the  term  has  been  applied  by  many  geologists  to  include  the  Inyo 
batholith  and  other  similar  granitic  rocks  to  the  east  and  north, 
far  into  Nevada  (Crowder  and  others,  1973,  p,  285  and  287), 


The  terrane  shown  on  the  State  Geologic  Map  as  the  Sierra 
Nevada  batholith  is  composed  of  granitic  rocks  of  various  com- 
positions and  is  made  up  of  a  number  of  separate  intrusive 
masses,  the  limits  of  which  have  often  not  been  delineated. 
Hence,  with  the  exception  of  a  number  of  satellitic  intrusive 
bodies  in  the  northwestern  part  of  the  Sierra,  the  main  Sierra 
Nevada  batholith  has  not  been  separated  into  its  component 
plutons  on  the  1977  Geologic  Map  of  California,  The  batholith 
has  been  studied  most  intensely  in  the  central  and  northern  parts 
by  the  U,S,  Geological  Survey  (for  example,  Bateman  and  oth- 
ers, 1963;  Hietanen,  1973).  In  general,  the  major  plutons  in  the 
western  part  of  the  batholith  are  older  and  more  mafic  than  those 
in  the  eastern  part.  Isotopic  ages  in  the  Sierra  Nevada  batholith 
range  from  Late  Triassic  to  Late  Cretaceous. 

The  granitic  rocks  of  the  southern  California  batholith  occupy 
an  area  about  97  km  (60  miles)  wide  and  more  than  1610  km 
(1,(X)0  miles)  long  extending  from  Riverside  to  the  southern  tip 
of  Baja  California.  Although  this  batholith  consists  of  many 


68 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


Table  15.      Batholiths,  plutons,  and  stocks  identified  on  the 
1977  Geologic  Map  of  California. 


NAME 

LOCATION 

Bath 

oliths 

English  Peak 

Klamath  Mountains 

Hunter  Mountain 

Inyo  Mountains 

Inyo 

Inyo-White  Mountains 

Ironside  Mountain 

Klamath  Mountains 

Shasta  Bally 

Klamath  Mountains 

Sierra  Nevada 

Sierra  Nevada 

Southern  California 

Peninsular  Ranges 

Wooley  Creek 

Klamath  Mountains 

Plutons 

Ashland 

Klamath  Mountains 

Bald  Rock 

Sierra  Nevada 

Bucks  Lake 

Sierra  Nevada 

Canyon  Creek 

Klamath  Mountains 

Caribou  Mountain 

Klamath  Mountains 

Cascade 

Sierra  Nevada 

Castle  Craggs 

Klamath  Mountains 

Craggy  Peak 

Klamath  Mountains 

Deadman   Peak 

Klamath  Mountains 

Forks  of  Salmon 

Klamath  Mountains 

Granite  Peak 

Klamath  Mountains 

Grizzly 

Sierra  Nevada 

Heather  Lake 

Klamath  Mountains 

Merrimac 

Sierra  Nevada 

Paiute  Mountain 

Inyo  Mountains 

Papoose  Flat 

Inyo  Mountains 

Pat  Keyes 

Inyo  Mountains 

Russian  Peak 

Klamath  Mountains 

Sage  Hen  Flat 

Inyo  Mountains 

Santa  Rita  Flat 

Inyo  Mountains 

Shelly  Lake 

Klamath  Mountains 

Slinkard 

Klamath  Mountains 

Swedes  Flat 

Sierra  Nevada 

Wildwood 

Klamath  Mountains 

Stc 

cks 

Mule  Mountain 

Klamath  Mountains 

Pit  River 

Klamath  Mountains 

separate  intrusive  masses  of  various  lithologic  composition 
(Larsen,  1951),  in  general,  individual  plutons  have  not  been 
identified.  No  individual  pluton  names  are  therefore  shown  on 
the  1977  Geologic  Map  of  California.  The  southern  Cahfomia 
batholith  is  known  to  be  overlain  by  fossiliferous  Upper  Creta- 
ceous sedimentary  rocks,  and  the  batholith  is  considered  to  have 
been  emplaced  in  early  Late  Cretaceous  time. 

Granitic  intrusive  masses  are  common  in  parts  of  the  Coast 
Ranges  west  of  the  San  Andreas  fault,  and  although  studied  in 
some  detail  (for  example,  Compton,  1966),  few  of  the  individual 
plutons  have  been  given  formal  names.  An  all-encompassing 
name  of  "Coast  Range  batholith"  has  been  applied  in  a  general 
sense  (Spotts,  1962),  but  more  commonly  the  granitic  terrane  is 
referred  to  as  "granitic  rocks  of  the  Salinian  Block,"  or  simply 
by  petrographic  descriptions  at  various  localities.  Determining 
the  age  of  these  granitic  rocks  is  not  without  problems,  but  they 
are  generally  interpreted  to  have  been  emplaced  during  Creta- 


ceous time  (Compton,  1966,  p.  277  and  287).  Because  of  the 
scattered  nature  of  the  intrusive  masses  (they  extend  from  Bode- 
ga Head  at  the  north  to  the  La  Panza  Range  at  the  south,  and 
include  the  Farallon  Islands,  Montara  Mountain,  Ben  Lomond 
Mountain,  parts  of  the  Santa  Lucia  Range,  and  the  Gabilan 
Mesa),  the  Coast  Range  batholith  could  not  meaningfully  be 
identified  on  the  Geologic  Map  of  California  by  that  name. 

Most  of  the  granitic  masses  found  in  the  Klamath  Mountains 
have  been  studied  and  named.  Some  of  the  larger  intrusive  bodies 
are  referred  to  as  batholiths;  the  others  are  described  as  plutons 
and  stocks  (Irwin,  1966;  Davis,  1966).  With  one  exception,  all 
are  of  Mesozoic  age  and  are  generally  thought  to  have  been 
emplaced  during  the  Nevadan  (Late  Jurassic)  orogeny  (Irwin, 
1966).  The  only  evidence  for  an  earlier  intrusion  comes  from  the 
small  Pit  River  stock,  whose  age  has  been  determined  as  Per- 
mian, 246  million  years  (Lanphere  and  others,  1968),  and 
is  shown  on  the  map  as  Paleozoic  granitic  rocks . 

The  granitic  rocks  of  the  Transverse  Ranges  are  of  various 
compositions  and  ages,  and  the  geologic  relations  among  the 
various  granitic  rocks  are  very  complex  and  not  completely  un- 
derstood. No  bathohths  as  such  have  been  named,  but  various 
areas  have  been  studied  in  detail.  The  oldest  of  the  plutonic 
rocks,  in  the  San  Gabriel  Mountains,  consisting  of  anorthosite 
and  related  rocks,  are  Precambrian.  Also  in  the  San  Gabriel 
Mountains  are  granitic  rocks  of  Permian-Triassic  age,  common- 
ly referred  to  as  the  Lowe  Granodiorite.  These  represent  one  of 
only  two  occurrences  of  recognized  Paleozoic  granitic  rocks  in 
the  state — the  other  lying  far  to  the  north  in  the  Klamath  Moun- 
tains, as  described  previously.  Mesozoic  granitic  rocks  are  also 
widespread  throughout  the  Transverse  Ranges,  extending  from 
the  Santa  Monica  Mountains  on  the  west  to  the  Eagle  Mountains 
on  the  east. 

The  numerous  scattered  granitic  plutons  in  the  Mojave  geo- 
logic province,  in  general,  have  not  been  studied  in  detail  and, 
as  far  as  the  writer  knows,  none  of  the  plutons  have  been  named. 
They  are  mostly  Mesozoic  in  age,  although  some  Precambrian 
bodies  are  known.  The  age  of  many  of  the  granitic  bodies  have 
now  been  radiometrically  determined  (Armstrong  and  Suppe, 
1973). 


Offshore  Geology 


Until  recently,  knowledge  of  the  geology  of  offshore  California 
has  been  largely  based  on  the  geologic  mapping  of  the  offshore 
islands  plus  crude  extrapolations  between  the  mainland  and  the 
islands.  There  has  also  been  speculation  as  to  the  location  of 
offshore  faults  based  on  the  configuration  of  sea-floor  bathyme- 
try. This  is  explained  on  page  28  ,  where  a  discussion  of 
ofTshore  structural  features,  as  determined  by  modem  geophysi- 
cal methods,  is  also  included. 

The  Geologic  Map  of  California  shows  the  same  offshore  fault 
locations  shown  on  the  Fault  Map  of  the  state,  but  in  addition, 
fold  axes  are  plotted.  A  separate  map  of  the  state  showing  the 
offshore  surFicial  geology  has  been  compiled  and  published  by 
the  California  Division  of  Mines  and  Geology  at  1:500,000  scale 
(Welday  and  Williams,  1975).  This  offshore  surficial  geologic 
map  provides  an  excellent  overview  of  the  distribution  of  rock 
and  various  types  of  sediments  on  the  ocean  bottom. 


1985 


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69 


REFERENCES  CITED 
IN  PARTS  I  AND  II 


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Curray,  J.R.,  and  Nason,  R.D.,  1967,  San  Andreas  fault  north  of  Point  Arena, 
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1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


71 


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Gionella,  V.P.,  1957,  Eorthquoke  and  faulting.  Fort  Soge  Mountains,  Califor- 
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Gionella,  V.P.,  and  Calloghan,  E.,  1934,  The  Cedor  Mountain,  Nevodo, 
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western  California,  in  Silver,  E.A.,  ond  Normark,  W.R.,  editors,  Son 
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Hart,  E.W.,  1980,  Fault-rupture  hozord  zones  in  California — Alquist-Priolo 
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74 


DIVISION  OF  MINES  AND  GEOLOGY 


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383  p. 

Welday,  E.E.,  and  Williams,  J.W.,  1975,  Offshore  surficiol  geology  of  Cali- 
fornia: California  Division  of  Mines  and  Geology  Mop  Sheet  26. 

Wentworth,  CM.,  Ziony,  J. I.,  and  Buchanan,  J.M.,  1970,  Preliminary  geolog- 
ic environmental  mop  of  the  greater  Los  Angeles  oreo,  California:  U.S. 
Geological  Survey  TID-25363,  41  p. 

White,  D.E.,  1968,  Thermal  and  minerol  waters  of  the  United  States — brief 
review  of  possible  origins,  in  Molkovsky,  M.,  editor.  Proceedings  of 
symposium  11,  mineral  and  thermal  waters  of  the  world:  Report  of  the  23rd 
Session,  International  Geological  Congress,  Czechoslovakia,  v.  19,  p. 
269-286. 

Williams,  Howel,  1934,  Mount  Shasta,  California:  Zeitschrtft  Fiir  Vulcanolo- 
gie,  Berlin,  Band  xv,  p.  225-253. 

Willis,  B.,  1923o,  A  fault  mop  of  California:  Bulletin  of  the  Seismological 
Society  of  America,  v.   13,  no.   1,  p.  1-12. 

Willis,  B.,  1923b,  Cooperation — to  members  of  the  Seismological  Society: 
Bulletin  of  the  Seismological  Society  of  Americo,  v.  13.,  no.  4,  p.  120-123. 

Willis,  B.,  and  Wood,  H.O.,  1922,  Fault  Mop  of  the  State  of  Colifornia: 
Seismological  Society  of  America,  scale  1:506,880. 

Wilot,  J. A.,  1972,  Anolysis  of  modern  vertical  deformation  in  the  western 
Transverse  Ranges,  unpublished  Master's  thesis,  University  of  Californio, 
Sonto  Barbara. 

Wood,  H.O.,  1916,  California  earthquakes,  o  synthetic  study  of  recorded 
shocks:  Bulletin  of  the  Seismological  Society  of  America,  v.  6,  nos.  2-3, 
p.  55-180. 

Wood,  H.O.,  1947,  Earthquakes  in  southern  California  with  geologic  rela- 
tions: Bulletin  of  the  Seismological  Society  of  America,  Part  1  in  v.  37, 
no.  2,  p.  107-157,  ond  Part  2  in  v.  37,  no.  3,  p.  217-268. 

Wood,  H.O.,  1955,  The  1857  eorthquoke  in  California:  Bulletin  of  the  Seis- 
mological Society  of  America,  v.  45,  no.   1,  p.  47-67. 

Woodring,  W.P.,  and  Bromlette,  M.N.,  1950,  Geology  and  paleontology  of 
the  Sonto  Mario  district,  California:  U.S.  Geological  Survey  Professional 
Paper  222,  185  p. 

Wright,  L.A.,  1975,  Late  Cenozoic  fault  patterns  and  stress  fields  in  the  Great 
Basin  and  westward  displocement  of  the  Sierra  Nevada  block:  Geology, 
V.  4,  p.  489-494. 

Yerkes,  R.F.,  1972,  Geology  and  oil  resources  of  the  western  Puente  Hills 
area,  southern  California:  U.S.  Geological  Survey  Professional  Paper 
420-C,  62  p. 

Ziony,  J.I.,  and  others,  1974,  Preliminary  mop  showing  recency  of  foulting 
in  coastal  southern  Californio:  U.S.  Geological  Survey  Mop  MF-585. 


PART  III 
APPENDICES 


False  facts  are  highly  injurious  to  the  progress  of  science,  for 
they  often  endure  long;  but  false  views,  if  supported  by  some 
evidence  do  little  harm,  for  everyone  takes  a  salutary  pleasure 
in  proving  their  falseness. 


-Charles  Darwin 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


77 


APPENDIX  A 

INDEX  TO  FAULT  NAMES 

SHOWN  ON  THE 

FAULT  MAP  OF  CALIFORNIA,  1975  EDITION 


NAMED  FAULTS  SHOWN 

A  list  of  all  the  faults  plotted  and  named  on  the  1975  edition 
of  the  Fault  Map  of  California  follows.  Because  of  space  prob- 
lems, not  all  these  faults  are  named  on  the  Geologic  Map  of 
California,  1977  edition,  although  an  attempt  was  made  to  iden- 
tify the  major  faults  on  that  map. 

The  faults  are  listed  alphabetically,  followed  by  the  name  of 
the  State  Atlas  sheet  on  which  the  fault  occurs.  Many  additional 
named  faults  occur  in  the  state,  and  a  good  number  of  these  are 
indicated  on  the  sheets  of  the  larger-scale  Geologic  Atlas  of 
California  (see  supplemental  index  to  fault  names,  p.  8  0  ). 

Many  other  named  faults  occur  in  California,  but  most  of 
these  could  not  be  identified,  even  on  the  Atlas  sheets,  because 
of  the  lack  of  space,  or  because  they  had  not  been  formally 
recognized  in  a  geologic  publication. 


PROCEDURE  FOR 
NAMING  FAULTS 


Of  course,  as  time  goes  on,  more  and  more  faults  will  be 
mapped  and  described  in  pubhshed  geologic  reports.  Although 
no  systematic  procedure  exists  for  naming  faults  (such  as  the 
"Code  of  Stratigraphic  Nomenclature"  devised  and  periodically 
expanded  by  the  American  Commission  on  Stratigraphic  No- 
menclature as  a  guide  for  naming  formations  and  other  strati- 
graphic units) ,  it  is  important  for  geologists  to  exercise  judgment 
in  devising  new  fault  names.  For  example,  most  faults  are  named 
after  nearby  prominent  geographic  features;  this  convenient 
practice  should  be  continued.  A  notable  exception  to  this  prac- 
tice is  the  recently  named  Hosgri  fault,  located  offshore  near  San 
Luis  Obispo  County.  The  need  to  name  this  fault  arose  when  it 
became  a  subject  of  concern  during  the  evaluation  of  the  seismic 
safety  of  the  adjacent  Diablo  Canyon  nuclear  power  plant.  There 
was  no  prominent  geographic  feature  noted  on  bathemetric 
charts  of  the  faulted  area  to  name  the  fault  after.  In  this  instance, 
it  was  decided  that  the  two  geologists  who  first  published  a  map 
showing  the  fault  should  be  recognized  in  the  name.  Thus,  the 
fault  became  known  as  the  "Hosgri"  fault — a  contraction  of  the 
first  parts  of  the  geologists'  names,  Hoskins  and  Griffiths. 

Although  naming  faults  does  not  require  the  kind  of  care  and 
consideration  to  detail  specified  for  naming  geologic  formations 
by  the  "Code  of  Stratigraphic  Nomenclature,"  a  cavalier  ap- 
proach can  easily  result  in  subsequent  confusion.  In  order  to 
avoid  confusion,  careful  consideration  should  be  given  to  the 
following  principles  when  naming  surface  faults. 

1.  A  fault  should  be  given  a  name  only  if  it  has  considerable 
length  or  offset,  or  is  situated  in  hazardous  proximity  to 
man-made  structures,  or  is  of  recent  origin,  no  matter  the 
length.  For  example,  any  future  fault  rupture  associated 
with  an  earthquake  (if  not  on  a  previously  recognized  or 


previously  named  fault),  warrants  a  name,  if  only  for  con- 
venience of  reference. 

The  name  of  a  geographic  feature  on  or  near  the  fault  should 
be  used  to  help  in  visualizing  its  location  or  "type  locality." 
This  practice  reduces  the  confusion  in  nomenclature  when 
faults  are  determined  to  be  connected  or  separated  by  fur- 
ther studies.  The  concept  of  a  type  locality  for  faults  was  first 
suggested  by  H.  J.  Buddenhagen,  M.  L.  Hill,  F.  S.  Hudson, 
and  A.  O.  Woodford  in  1930  (Bulletin  of  the  American 
Association  of  Petroleum  Geologists,  v.  14,  no.  6,  p.  797- 
798).  Over  the  years  this  practice  has  not  always  been  fol- 
lowed, but  it  is  strongly  recommended  that  the  type  locality 
be  an  integral  part  of  any  description  of  a  newly  described 
fault.  The  first  public  description  of  a  fault  should  include 
an  accurate  location  of  its  trace,  preferably  by  an  adequate- 
scale  map,  and  a  description  of  its  best  exposure  ("type 
locality"). 

As  much  information  as  can  be  determined  about  the  geom- 
etry of  the  fault  should  be  described,  including  length,  direc- 
tion of  prevalent  strike,  direction  and  magnitude  of  dip,  and 
recency  of  movement  as  can  best  be  determined.  The 
amount  of  displacement  should  be  given  if  it  can  be  reason- 
ably deduced,  with  careful  attention  being  given  to  the  dis- 
tinction between  separation  and  slip,  that  is,  the  distinction 
between  displacement  between  the  traces  of  a  displaced 
plane  on  two  sides  of  a  fault  and  displacement  of  points  that 
were  formerly  adjacent  (see  J.  C.  Crowell,  1959,  Bulletin  of 
the  American  Association  of  Petroleum  Geologists,  v.  43, 
no.  11,  p.  2653-2674).  If  not  enough  of  these  factors  can  be 
determined,  the  naming  of  the  fault  should  perhaps  be 
delayed  until  more  is  known  about  it. 

Previously  used  fault  names  should  not  be  used  for  faults  in 
other  areas  of  the  state  that  might  have  a  similarly  named 
geographic  feature.  To  do  so  creates  confusion.  For  example, 
we  have  already  three  "San  Jose  Faults"  in  the  state,  and 
four  "Hot  Springs  faults,"  two  of  which  are  less  than  25 
miles  apart!  Even  though  the  following  indexes  of  fault 
names  are  incomplete,  they  should  be  consulted,  and  similar 
names  should  be  avoided.  As  the  Division  of  Mines  and 
Geology  publishes  updated  fault  maps  of  the  state,  it  will 
incorporate  new  fault  names.  It  would  be  helpful  and  it 
would  ensure  completeness  if  newly  described  faults  are 
called  to  our  attention  and  a  description  provided  to  this 
Division.  Such  information  should  be  addressed  to  the  atten- 
tion of  the  State  Geologist,  California  Division  of  Mines  and 
Geology,  Resources  Building,  Room  1341,  1416  Ninth 
Street,  Sacramento,  CA  95814. 

In  recent  years,  with  the  advent  of  strong  earthquakes  with 
new  (or  newly  recognized)  faults,  the  intensity  of  investiga- 
tion has  sometimes  resulted  in  different  names  being  applied 


78 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


to  the  same  fault  by  various  investigators.  It  is  important 
that  different  names  for  the  same  fault  not  enter  the  Htera- 
ture  where  future  confusion  is  created.  Here  again,  if  the 
State  Geologist  is  regularly  informed  before  publication,  du- 
plicate fault  names  can  be  avoided  and  suitable  arbitration 
can  be  provided  in  questions  of  priority  of  name,  or  of  nam- 
ing different  traces  of  the  same  fault  zone. 

A  special  problem  arises  when  two  or  more  separately 
mapped  and  named  faults  are  found  to  join,  after  additional 
work  has  been  done.  When  this  occurs,  giving  the  fault  a  new 


name  or  applying  one  of  the  original  fault  names  to  the 
entire  length  of  the  fault  may  be  warranted.  If  such  a  change 
is  proposed,  the  proposal  should  be  accompanied  by  a  de- 
tailed analysis  of  the  situation,  well  documented  by  maps, 
fully  explained  in  a  text,  and  the  proposal  published  in  a 
recognized  geological  journal.  A  good  example  of  this  is  the 
case  of  the  Espinosa,  San  Marcos,  and  Rinconada  faults, 
now  recognized  as  the  same  fault,  for  which  Dibblee  has 
proposed,  in  U.S.  Geological  Survey  Professional  Paper  981, 
that  the  name  Rinconada  be  applied  to  the  entire  length  of 
the  fault. 


INDEX  TO  FAULT  NAMES 

Faults  Usted  are  those  shown  on  the  1975  edition  of  the  Fault  Map  of  California.  To  aid  in  their  location,  the  1°  x  2°  State  Atlas 
sheet  on  which  the  fault  lies  is  indicated  in  parentheses.  Abbreviations  of  sheet  names  are  identified  at  the  end  of  the  list.  An  asterisk 
indicates  a  fault  not  shown,  or  not  named,  on  the  1:250,000  scale  Geologic  Atlas. 


Agua  Cahente  (SA) 

Alamo  Mt.   thrust  (LA) 
♦Algodones  (EC) 

Aliso  (SA) 
*Amedee  (Su) 

Arroyo  Parida  (LA) 

Bald  Mountain  (R,  W) 

Banning  (SA,  SB) 
*Bat  Mountain  (DV) 

Bear  Mountain  (Sac,  SJ) 

Bear  Valley  (SC) 

Ben  Lomond  (SF) 
•Big  Bend  (C) 

Big  Pine  (LA) 

Big  Spring  (SLO,  B) 

Blackwater  (T) 

Blake  Ranch  (SB) 

Bloomfield  (SR) 

Blue  Cut  (SS,  SA) 

Blue  Rock  (SC) 
•Bradley  Canyon  (SM) 
•Brawley  (EC,  SS) 

Breckenridge  (B) 
•Browns  Valley  (SC) 

Buena  Vista  (B) 

Bullion  (SB,  N) 
•Burdcll  Mountain  (SR) 

Butano  (SJ,  SF) 

Cady  (SB) 

Calaveras  (SC,  SJ) 

Calico  (SB) 

Calico,  West  (SB) 
•Calipatria  (EC,  SS) 
•Camel  Peak  (C) 

Camp  Rock  (SB) 

Cantil  Valley  (T) 
•Carmel  Canyon  (SC) 

Casa  Loma  (SA) 

Cedar  Canyon  (K) 

Chabot,  East  (SF) 

Chamock  (LA,  LB) 

Chino  (SA,  SB) 

Church  Creek  (SC) 


Claremont  (SA,  SB) 
•Clark  (SA) 

Clearwater  (LA) 
•Coast  Range  thrust  (LA,  SR, 
R,  W,  U,  SM,  SJ,  SC,  SLO) 

Coast  Ridge  (SLO,  SC) 
•Cold  Fork  (R) 
•Concord  (SR,  SJ,  SF) 

Coyote  Creek  (SA) 

Coyote  Lake  (T) 

Cristianitos  (SA) 

Cucamonga  (SB) 
•Cypress  Point  (SC) 
•Dead  Mountains  (K,  N) 

Death  Valley  (see  Northern 
Death  Valley-) 

Death  Valley  Graben  (DV) 
•Death  Valley,  South  (DV,  T) 
•Del  Norte  (W) 

Dillon  (SA,  SB) 
•Dogwood  Peak  (C) 

Durrwood  (B) 

Earthquake  Valley  (SA) 
•East  Fork  (W,  R) 

Edison  (B) 

Elder  Creek  (R) 
•El  Modeno  (SA) 

El  Paso  (T) 

Elsinore  (SA,  SD) 

Emerson  (SB) 

Falor  (R) 
•Fort  Sage  (Su) 

Franklin  (SF,  SR) 

Freshwater  (R) 

Furnace  Creek  (DV) 

Garhc  Spring  (T) 

Garlock  (B,  LA,  T) 

Garlock,  North  Branch  (LA) 

Garlock,  South  Branch  (LA) 
•Goat  Ranch  (B) 

Green  Valley  (SR) 

Grizzly  Valley  (C) 

Grogan  (W,  R) 


•Grouse  Point  (W) 

Halloran  (K) 

Harper  (SB,  T) 

Harris  (SA) 

Hayward  (SF,  SJ) 

Healdsburg  (SR) 

Helendale  (SB) 
•Hidalgo  (SB) 

Hidden  Springs  (SS) 

Hildreth  (LA) 

Hilton  (M) 

Hitchbrook  (LA) 

Hoadley  (R) 

Holser  (LA) 
•Honey  Lake  (Su,  C) 
•Hosgri  (SLO,  SM) 

Hot  Springs  (C,  SA-2,  SS) 

Huasna,  East  (SLO) 

Imperial  (EC) 

Independence  (F) 

Ivanpah  (K) 

Jawbone  (B) 

Jewett  (B) 

Johnson  Valley  (SB) 

Jolon  (SLO) 

Kern  Canyon  (B,  F) 
•Kern  Front  (B) 
•Kern  Gorge  (B) 
•King  City  (SC) 

Korbel  (R) 
•Laguna  Salada  (EC) 
•La  Honda  (SF) 
•La  Nacion  (SD) 
•La  Panza  (SLO,  B) 

Last  Chance  (C) 

Lenwood  (SB) 

Leuhman  (SB) 

Liebre  (LA) 

Likely  (A,  Su) 
•Litchfield  (Su) 

Little  Pine  (LA,  SM) 

Little  Salmon  (R) 

Livermore  (SJ) 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


79 


Lockhart  (T.  SB) 
•Lockhart,  South  (T) 
*Los  Lobos  (SC,  SLO) 
Los  Pinos  (SA) 
•Lucia  (SC) 
Ludlow  (SB,  N) 
Madrone  Springs  (SJ) 
Malibu  Coast  (LA) 
Mallethead  thrust  (W) 
Manix  (SB) 
•Manly  Pass  (T) 
•McCuUough  (K) 
Melones  (C,  SJ,  Sac,  Su,  M) 
•Mendocino  (R) 
Mesa  (LA) 

•Mesquite  Lake  (SB,  N) 
Midland  (Sac,  SJ) 
Mirage  Valley  (SB) 
Mission  Creek  (SB,  SA) 
•Mohawk  Valley  (C) 
•Monterey  Bay  (SC) 
•Monterey  Canyon  (SC) 
Morales  (B,  LA) 
More  Ranch  (LA) 
Morongo  Valley  (SB) 
Mount  Poso  (B) 
Munson  Creek  (LA) 
Muroc  (T,  B) 
Nacimiento  (SLO) 
Newport-Inglewood  (LB,  LA,  SA) 
Northern  Death  Valley-Furnace  Creek 
(M,  DV) 
•North  Fork  (R,  W) 
Northridge  Hills  (LA) 
Norwalk  (LB,  SA) 
•Oak  Flat  (R) 
Oakridge  (LA) 
Old  Woman  Springs  (SB) 
•Orleans  (W) 
Ortigalita  (SJ,  SC) 
•Owens  VaUey  (M,  F,  DV) 
Owl  Lake  (T) 
Ozena  (LA) 
Pacifico  (SM) 
Paicines  (SC) 
•Palo  Alto  (SF) 
Palo  Colorado  (SC) 
Palo  Colorado-San  Gregorio  (SF,  SC) 
Palos  Verdes  (LB) 


Panamint  Valley  (T,  DV) 

Paskenta  (U,  R) 

Pastoria  (LA) 

Pilarcitos  (SF) 

Pine  Mountain  (LA) 

Pinnacles  (SC) 

Pinto  Mountain  (SB,  N) 

Pinyon  Peak  (B) 

Pipes  Canyon  (SB) 

Pisgah  (SB) 

Pleasanton  (SJ) 

Pleito  (LA,  B) 
•Point  Reyes  (SR,  SF) 
•Pond-Poso  Creek  (B) 

Porcupine  Wash  (SS) 

Punchbowl  (SB) 

Raymond  (Raymond  Hill)  (LA) 

Recruit  Pass  (B) 
•Red  Hill  (SB) 

Red  Mountain  (LA) 

Refugio  (SM) 

Reliz  (SC) 
•Rialto-Colton  (SB) 
•Rich  Bar  (Su,  C) 

Rinconada  (SC,  SLO,  LA,  SM) 

Rodgers  Creek  (SR) 

Rosamond  (LA) 
•Rose  Canyon  (SD,  SA) 

Salton  Creek  (SS) 

San  Andreas  ( SS,SB,  SA,  LA.  B, 
SLO,  SC,  SJ,  SF,  SR,  U,  R) 

San  Andreas,  North  Branch  (SB) 

San  Andreas,  South  Branch  (SB) 

San  Benito  (SC) 

San  Bruno  (SF) 

San  Cayetano  (LA) 
•San  Clemente  (LB) 
•Sand  Hills  (EC,  SS) 

San  Fehpe  (SA) 

San  Fehpe  Hills  (SA) 

San  Francisquito  (SC,  LA) 

San  Gabriel  (LA,  SB) 

San  Gregorio  (SF) 

San  Jacinto  (SA,  SB) 

San  Jose  (LA,  SB,  SJ,  SF) 

San  Juan  (SLO,  B) 

Santa  Cruz  Island  (LA,  LB,  SM) 
•Santa  Maria  (SM) 

Santa  Monica  (LA) 


Santa  Rosa  Island  (SM) 

Santa  Susana  thrust  (LA) 

Santa  Ynez  (LA,  SM) 

Santa  Ynez,  South  Branch  (SM) 

Sargent  (SC,  SJ) 

Sawpit  Canyon  (SB,  LA) 

Seal  Cove  (SF) 
•Shady  Canyon  (SA) 
•Sheephead  (T) 

Sierra  Madre  (LA,  SB) 

Sierra  Nevada  (M,  F,  DV,  T,  B) 

Silver  Creek  (SJ,  SF) 
•Simi  (LA) 

Spring  (SB) 
•Spring  Creek  thrust  (R) 

Springs  (B,  LA) 
•Stanford  (SF) 

State  Line  (K) 

Stockton  (Sac,  SJ) 

Suey  (SM) 
•Sulphur  Spring  (R) 

Superstition  Hills  (SS,  EC) 

Superstition  Mountain  (EC) 

Sur  (SC) 

Sur-Nacimiento  (SC) 

Surprise  Valley  (A) 

Sweitzer  (SR) 

Tejon  Canyon  (B) 
•Temescal  (SA) 

Tesla  (SJ) 

Tolay  (SR) 

Tularcitos  (SC) 

Tule  Creek  (LA) 
•Twin  Sisters  (R,  W) 

Verdugo  (LA) 

Vergales  (SC) 

Verona  (SJ) 

Vincent  thrust  (SB) 

Walnut  Creek  (SB) 
•Waltham  Canyon  (SC,  SLO) 
•White  Mountains  (M) 

Whiterock  (B,  LA) 

White  Wolf  (B) 

Whittier  (SA,  LB) 

Willow  Creek  (SC) 
•Willows  (U,  C) 
•Wilson  Canyon  (T) 

Yager  (R) 

Zayante  (SF,  SJ) 


Abbreviations  of  Mop  Sheets 


A  =  Alturas 

B  =  Bakersfield 

C  =  Chico 

DV  =  Death  Valley 

EC  =  El  Centre 

F  =  Fresno 

K  =  Kingman 

LA  =  Los  Angeles 

LB  =  Long  Beach 


M  =  Mariposa 
N  =  Needles 
R  =  Redding 
SA  =  Santa  Ana 
Sac  =  Sacramento 
SB  =  San  Bernardino 
SC  =  Santa  Cruz 
SD  =  San  Diego 
SF  =  San  Francisco 
SJ  =  San  Jose 


SLO  =  San  Luis  Obispo 

SM  =  Santa  Maria 

SR  =  Santa  Rosa 

SS  =  Salton  Sea 

Su  =  Susanville 

T  =  Trona 

U  =  Ukiah 

W  =  Weed 

WL  =  Walker  Lake 


80 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


SUPPLEMENTAL  INDEX  TO  FAULT  NAMES 

Faults  listed  here  are  not  shown  on  the  1975  edition  of  the  Fault  Map  of  California  because  of  space  problems,  but  they  are  shown 
on  the  individual  sheets  of  the  1:250,000  scale  Geologic  Atlas  of  California,  O.  P.  Jenkins  edition.  The  sheets  on  which  the  faults  occur 
are  indicated  in  parentheses;  abbreviations  used  are  the  same  as  those  used  in  the  previous  index  to  faults. 


Acton  (LA) 

Agua  Blanca  thrust  (LA) 

Agua  Dulce  Canyon  (LA) 

Agua  Tibia  (SA) 

Aguanga  (SA) 

Aliso  Canyon  (SA) 

Amargosa  thrust  (T) 

Americano  Creek  (SR) 

Arnold  Ranch  (SA) 

Arrastre  Spring  (T) 

Ash  Hill  (DV) 

Avalon-Compton  (LB) 

Bee  Canyon  (LA) 

Ben  Trovato  (SJ) 

Berrocal  (SJ) 

Bicycle  Lake  (T) 

Black  Butte  (SJ) 

Black  Mountain  (SR) 

Bolinger  (SF) 

Brown  Mountain  (T) 

Bryant  (SA) 

Buck  Ridge  (SA) 

Butte  Valley  (T) 

Cabrillo  (LB) 

Cajon  Valley  (SB) 

Cameros  (LA) 

Camuesa  (LA) 

Carnegie  (SJ) 

Cameros  (SR) 

Chabot  (SF) 

Chalone  Creek  (SC) 

Cherry  Hill  (LB) 

Childers  Peak  (SR) 

Chimeneas  (SLO) 

Clark  Mountain  (K) 

Cleghom  (SB) 

Clemens  Well  (SS) 

Collayomi  (SR) 

Cook  Peak  (B) 

Cottonwood  (LA) 

Cox  Ranch  (SA) 

Cull  Creek  (SF) 

Curry  Mountain  (SC) 

Cuyama  (SLO) 

Cuyama,  South  (LA) 

Diamond  Bar  (SA) 

Doble  (SB) 

Dos  Pueblos  (LA) 

Dry  Creek  (LA) 

Duarte  (SB) 

Dublin  (SJ) 

Eisner  (SR) 

Espinoza  (SC,  SLO) 

False  Cape  Shear  Zone  (R) 

Fitch  Mountain  (SR) 

Frazier  Mountain,  North  (LA) 

Frazier  Mountain,  South  (LA) 

Gandy  Ranch  (SA) 

Garnet  Hill  (SA) 

Glen  Anne  (LA) 

Glen  Helen  (SB) 


Glen  Ivy  (SA) 

Goose  Lake  (A) 

Gravel  Pit  (SJ) 

Green  Ranch  (LA) 

Greenville  (SJ) 

Handorf  (SB) 

Harper  Lake  (SB) 

Hillside  (SF) 

Holmes  (SB) 

Honda  (SM) 

Huer  Huero  (SLO)  (now  La  Panza) 

Indian  Hill  (SB) 

Indio  Hills  (SA) 

Juncal  Camp  (LA) 

Keene  Wonder  (DV) 

Kennedy  (SR) 

Kern  River  (B)  (now  Kern  Gorge) 

Kramer  Hills  (SB) 

Laguna  Canyon  (SA) 

Lancaster  (SA) 

Las  Tablas  (SLO) 

Las  Trampas  (SF) 

Lavigia  (LA) 

Lawrence  (SA) 

Leach  Lake  (T) 

Limekiln  (SJ) 

Little  Oak  Canyon  (LA) 

Little  Rock  (LA) 

Little  Sulphur  (SR) 

Lockwood  (LA) 

Loma  Aha  (LA) 

Loma  Linda  (SB) 

Lone  Tree  (LA) 

Maacama  (SR) 

Magic  Mountain  (LA) 

Maguire  Peaks  (SJ) 

Mattole  (R) 

McWay  thrust  (SC) 

Mecca  Hills  (SA) 

Mesquite  (SB)  (now  Mesquite  L.) 

Mesquite  thrust  (K) 

Middle  (K) 

Midway  (SJ) 

Mill  Creek  (SB) 

Miller  Creek  (SF,  SC) 

Mint  Canyon  (LA) 

Mission  (SJ) 

Mission  Ridge  (LA) 

Mount  Diablo  (SJ) 

Mount  Jackson  (SR) 

Mule  Spring  (T) 

Nadeau  (LA) 

New  Idria  thrust  (SC) 

North  (K) 

North  Fork  (SC) 

Old  Dad  (K) 

Orocopia  thrust  (SS) 

Overland  Avenue  (LA) 

Palm  Canyon  (SA) 

Park  Hill  (SA) 

Parks  (SJ) 


Patterson  Pass  (SJ) 

Pelican  Hill  (SA) 

Pelona  (LA) 

Pick  Creek  (SC) 

Pine  Rock  (SC) 

Pinecate  (SC) 

Pinole  (SF) 

Pinyon  Hill  (LA) 

Pole  Canyon  (LA) 

Protrero  (LB) 

Red  Hills  (SLO) 

Rincon  (SJ) 

Round  Mountain  (B) 

Russ  (R) 

San  Antonio  (SLO) 

San  Dimas  Canyon  (SB) 

San  Guillermo  (LA) 

San  Juan  (SA) 

San  Marcos  (SLO) 

San  Pablo  (SF,  SR) 

Santa  Rosa  (LA)  (now  Simi) 

Santa  Ynez,  North  Branch  (SM) 

Seal  Beach  (LB) 

Shannon  (SJ) 

Sidewinder  (SB) 

Sierra  Azul  (SJ) 

Soda  Creek  (SR) 

Soda  Spring  (SJ) 

Soledad  (LA) 

South  (K) 

South  Fork  Mountain  (R,  W) 

Southhampton  (SR) 

St.  John  Mountain  (SR) 

Stewart  (SA) 

Stony  Brook  (SJ) 

Stony  Creek  (U) 

Sunol  (SF) 

Sycamore  (LA) 

Temple  Hill  (SA) 

Tenaja  (SA) 

Thomas  Mountain  (SA) 

Towne  (DV) 

Tracy  (Stockton)  (SJ) 

Transmission  Line  (LA) 

Tyler  Horse  (LA) 

Tyler  Valley  (SB) 

Valle  (SJ) 

Vasquez  Canyon  (LA) 

Water  Tank  (SJ) 

Welch  (SJ) 

West  Huasna  (SLO) 

Wildcat  (SF) 

Wildomar  (SA) 

Wilhams  (SJ) 

Willow  Springs  (LA) 

Wilson  (SR) 

Winters  thrust  (K) 

Woods  (SR) 

Workman  Hill  fault  extension  (LA) 

Wragg  Canyon  (SR) 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


81 


APPENDIX  B 

TABULATED  LIST  OF 
THERMAL  SPRINGS  AND  THERMAL  WELLS 


The  following  tabulation  provides  additional  data  for  the  ther- 
mal springs  and  wells  shown  on  the  Fault  Map  of  California. 
These  data  include  information  on  location,  water  temperature, 
references,  some  notes,  and,  in  the  case  of  wells,  the  total  depth 
and  year  drilled. 

DATA  USED  AND 
ACKNOWLEDGMENTS 

Multiple  references  are  often  indicated  on  the  tabulated  Ust 
because  in  many  instances  supplementary  references  can  be  help- 
ful in  locating  the  spring  or  well  more  precisely  on  a  map  or  in 
finding  it  in  the  field.  In  addition,  many  of  these  references 
(especially  the  more  recent  ones)  contain  data  pertaining  to 
chemistry  and  physical  properties  (for  example,  conductivity, 
discharge  rate,  and  isotopic  analysis).  In  addition  to  the  pub- 
Ushed  references  Usted,  unpubUshed  data  were  acquired  from 
Robert  W.  Rex  (Repubhc  Geothermal,  Inc.),  James  B.  Koenig 
(Geothermex),  and  Sanford  L.  Werner  (California  Department 
of  Water  Resources).  To  these,  I  wish  to  express  my  gratitude. 
Help  in  plotting  and  tabulating  these  data  was  ably  provided  by 
John  Sackett,  Melvin  C.  Stinson,  Robert  A.  Switzer,  and  Duane 
A.  McClure. 


LOCATING  THERMAL  SPRINGS 
AND  WELLS 


Locations  of  many  thermal  springs  and  wells,  especially  many 
of  those  listed  in  the  earher  publications,  were  vague  and  difficult 
to  plot.  A  reason  for  this  was  the  lack  of  adequate  base  maps  for 
many  parts  of  the  state  when  these  earUer  reports  on  hot  springs 


and  wells  were  made.  If  later  reports  did  not  clarify  the  locations, 
county  records  were  examined  (old  copies  of  official  county 
maps,  as  well  as  early  Mines  and  Mineral  Resources  Reports  by 
the  California  Division  of  Mines  and  its  predecessor,  the  State 
Mining  Bureau).  Particularly  useful  in  locating  many  early  ther- 
mal springs  and  resorts  was  a  book  entitled  "Mineral  Springs 
and  Health  Resorts  of  California"  (1892),  by  Winslow  Ander- 
son, Professor  of  Medicine  at  the  University  of  California  Medi- 
cal School,  San  Francisco.  Because  the  early  references  often  did 
not  give  the  location  of  the  thermal  springs  and  wells  by  town- 
ship, range,  and  section,  these  data  were  often  determined  by  the 
compilers  where  possible,  from  7'/;-  or  15-minute  quadrangles.  In 
unsurveyed  land,  the  locations  were  described  by  the  compilers 
by  latitude  and  longitude  from  the  published  quadrangles. 

The  thermal  springs  and  wells  are  shown  on  the  Source  Data 
Index  maps  (Appendix  D)  as  circles  for  theimal  springs  and  as 
squares  for  thermal  wells.  These  spring  and  well  locations  are 
numbered,  starting  with  "1"  (one)  for  each  atlas  sheet.  These 
coded  numbers  refer  to  the  tabulated  data  in  the  following  Ap- 
pendix B.  On  the  Fault  Map  of  CaUfomia,  the  thermal  springs 
and  wells  are  shown,  but  are  not  coded  by  number. 

It  should  be  noted  that  a  number  of  the  thermal  springs  are 
actually  shallow  wells  that  were  dug  or  drilled  for  water  but 
came  in  flowing  as  artesian  wells.  Oftentimes  such  artesian  wells 
were  dug  for  convenience  in  areas  where  no  springs  occur,  so 
both  wells  and  springs  are  intimately  associated  and,  in  fact,  on 
the  early  records  often  the  two  are  not  clearly  differentiated. 

Following  the  convention  estabhshed  in  reports  by  G.  A.  War- 
ing (1915  and  1965),  which  were  the  principal  sources  used 
when  this  present  compilation  was  started,  the  writer  considered 
as  thermal  only  those  springs  that  are  more  than  15°F  (8.3°C) 
above  the  mean  annual  temperature  of  the  air  at  their  locaUties. 
In  the  case  of  drilled  wells,  a  normal  thermal  gradient  of  about 
IT  increase  for  each  100  feet  of  depth  (2°C  for  each  100  meters) 
was  taken  into  consideration  when  determining  whether  the  well 
should  be  classified  as  thermal. 


82 

ALTURAS   SHEET 

DIVISION  OF  MINES  AND  GEOLOGY                                                        BULL.  201 

APPENDIX   B   -   TABULATED   LIST  OF  THERMAL   SPRINGS   AND  WELLS 

• 

HAP 

LOC. 
HO. 

NAME 

LOCATIOM 

QUADRANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
<FEET) 

YEAR 

DRILLED 

REFERENCE (S) 
(see    list   of    references    for   abbreviations) 

NOTES 

T 

R 

SEC. 

BW 

PUBLICATION 

YEAR 

PAGE 

UX. 
NO. 

1 

Har«  sprinq 

48N 

9E 

33 

N> 

Steele  Swan^idS') 

Pars,  coma.,  J.B. 
Koenig 

J 

Pothole  Spring 

46N 

9E 

15 

M) 

Steele  SwampClS') 

70 

USGS   P.P.    49? 

1965 

20 

4 

70 

USGS  WSP    338 

1915 

334 

Modoc 

1 

46N 

gc 

15 

M) 

78 

Tea^.   by  Burnett 
ft  Jennings  9/71 

3 

Hot    springs  or 
Bldwll  Creek 

46N 

16E 

e  or 

n 

IC 

Fort  BldwelKlSM 

97-108 

USGS   P.P.    492 

1965 

20 

12 

108 

USGS  WSP    338 

1915 

121-122 

Modoc 

10 

Fort  BWwell   Hot 

Springs 

46N 

16E 

8  «  n 

H) 

109- 
115 

USGS  Geoth.  Modoc  Co. 
(Open   file) 

1974 

ea 

2  springs 

Fort  Bl<i«ell  Res. 
Hot  Springs 

4eN 

leE 

17 

H) 

111 

CDOG  TR    15 

1975 

Table 
4a 

1 

Peterson  Ranch  Well, 
Buchner'B  Well, 
Fort  Bid-ell   Well 

46N 

16E 

e  »n 

H) 

97-108 

CDOG   TR    13 

1975 

47 

1,    2,    3 

4 

Spring,   north  of 
Big  Glass   Mtn. 

44N 

3E 

1 

M) 

Medicine  Lake 
(15'> 

191 

USGS   P.P.    49? 

1965 

20 

3A 

Location  vague 

5 

Spring,    near 
Rattlesnake  Creek 

43N 

12E 

22? 

K) 

Big  Sage  Res. 
(15') 

80 

USGS  P.P.    49? 

1965 

20 

5 

L^ication  vague 

- 

USGS  WSP    338 

1915 

120 

Modoc 

8 

6 

Hagma  Energy   Inc. 
Paman  1 

44N 

15E 

24 

W 

Cedarville   (ISM 

283 

2150 

1959 

USGS  Geoth.   Modoc  Co. 
(Open  file) 

1974 

6a 

Mag&a  Energy  Inc. 
Parman   2 

44N 

15E 

24 

W 

257 

1968 

1959 

USGS  Geoth.   Nadoc  Co. 
(Open  file) 

1974 

6a 

Ha<;pu  Energy  Inc. 
Paraan   3 

44N 

15E 

24 

M) 

- 

92 

1962 

USGS  Geoth.   Modoc  Co. 
(Open  file) 

1974 

6a 

Rig  destroyed  by 
blo-out 

Ha^u  ^ergy   Inc. 
Phipps  1 

44N 

15E 

24 

ICI 

278 

1267 

1962 

USGS  Geoth.   Modoc  Co. 
(Open  file) 

1974 

6a 

rtogaa  Energy  Inc. 
Phipps   2 

44N 

15E 

24 

K) 

Cedarvllle   (15') 

320 

4500 

1972 

USGS  Geoth.  Modoc  Co. 
(Open  file) 

1974 

6a 

Wells 

32C 

max. 

4500 

CDOG  TR   13 

1975 

47 

5 

7 

Several   springs  at 
site  of  Kjd 
"volcanoes" 

120- 
207 

USGS   P.P.    492 

1965 

20 

14 

Hot  springs  north 
of  Lake  City 

- 

USGS  WSP    338 

1915 

122-123 

Msdoc 
11 

Hid  volcano  and 
hot  springs 

44N 

15E 

24 

H) 

Cedarville   (15-) 

118- 
207 

CDOG  TR   13 

1975 

47 

4 

"Lake  City  Bid 
explosion" 

205 

CDOG  TR   15 

1975 

Table 
4a 

2 

B 

Boyd    Spring 

45N 

17E 

31 

M) 

Cedarvllle   (15') 

70 

USGS   P.P.    492 

1965 

20 

13 

Now  only   50"F, 
Marshal  Reed,    CDOG, 
pers.  cos».    7/1/74 

67 

USGS  WSP    338 

1915 

124 

Hxloc 
12 

9 

Hot   springs 

43N 

ISE 

12 

H3 

Cedarville   (15* ) 

140- 
149 

USGS  P.P.    492 

1965 

20 

16 

Waring's    location 
(18E)   corrected 

- 

USGS  WSP    338 

1915 

123 

14 

43N 

16E 

12 

K> 

185 

USGS  Geoth.   Hodoc  Co. 
(Open  file) 

1974 

8a 

Several  springs 

Seyferth  Hot  Springs 

186 

CDOG  TR    15 

1975 

Table 
4a 

3 

Seyferth  Hot   Springs 

IBS 

CDOG  TR   13 

1975 

47 

9 

10 

Leonards  Hot  Springs 

43N 

leE 

13 

H} 

Cedarville  (15') 

106 

USGS  Geoth.   ttidoc  Co. 
(Open  file) 

1974 

ea 

B 

149 

CDOG  TR   13 

1975 

47 

10 

U 

Leonards   Hot    Springs 
(east) 

Cedarvllle    (15M 

150 

USGS   P.P.    49? 

1965 

20 

17 

Waring's   location 
corrected 

S««  Appendix  D  for    location. 


1985 

1 TURAS    SHEET 

TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA                                83 

APPENDIX   B   -    TABULATED   LIST   OF   THERMAL   SPRINGS  AND  WELLS 

ip 

C.                            NAME 

LOCATICW 

QUADRANGLE 

WATER 
TEHP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 
(see   Hat  of  references   for  abbreviations) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATION 

YEAR 

PAGE 

WC. 

NO. 

I      Leonards  Hot  Springs 
(east) 

4  3N 

16£ 

13 

rc 

CedarvlUe    {15-  ) 

- 

uses  WSP   3  38 

191S 

123 

tt>doc 
13 

Hot  springs 

143 

CDOG  TR   15 

1975 

Table 
4a 

4 

150 

USG5  (;eot}l.  Kxloc  Co. 
(Open  file) 

1974 

8a 

A 

144 

CDOC  TR    13 

1975 

47 

11 

A     Hutchens  Well 

4?N 

16E 

20 

H) 

C«]arville   (15') 

lie 

400 

(330G  TR    13 

1975 

47 

6 

B     Well 

43N 

16E 

20 

tc 

Cedarville  (15') 

156 

650 

CDOG  TR   13 

1975 

47 

7 

C     RoM son's  Well 

43N 

16E 

30 

lO 

CedarvUle   (15') 

122 

250 

CDOG  TR    13 

1975 

47 

e 

ll»t  springs 

42N 

16E 

1 

tc 

Cedarville    (15' ) 

130 

USGS   P.P.   492 

1965 

20 

18 

200 

uses  Geoth,   Modoc  Co. 
(Open  file) 

1974 

ea 

D 

" 

USGS  WSP   338 

1915 

123 

Modoc 
15 

Hot  Springs   Motel 
Hell 

42N 

ITE 

e 

H) 

Cedarvllle   (15') 

210 

90 

CDOG  TR    15 

1975 

Table 
4a 

5 

Hot  Springs  Hotel 
Hells 

183- 
20B 

~ 

CDOG  TR   13 

1975 

47 

13 

Magna  Energy,    Inc., 
CedarvUle  (*1 

129 

734 

1962 

USGS  Geoth.   Modoc  Co. 
(Open  file) 

1974 

6a 

BenBSC  Hot   Springs 

42N 

17E 

6 

H) 

Cedarvllle   (15') 

205- 
207 

CDOG  TR   13 

1975 

47 

15 

Surprise  Valley 
mneral  Wells 

Isprinas) 

209 

USGS  Geoth.   MDdoc  Co. 
(Open   file) 

1974 

8a 

C 

Gcoth«nul  Resources 
Int.  Kelly  Hot 
Spring  1 

42N 

lOE 

29 

W> 

Canby   (15' ) 

230 

3206 

1969 

USGS  Geoth.   Modoc  Co. 
(Open  file) 

1974"^ 

6«    ■ 

Well 

42N 

lOE 

29 

M) 

Canby    (15') 

230 

3206 

- 

CDOG   TR    13 

1975 

47 

20 

Kelly  Hot   Springs 

42N 

lOE 

29 

W) 

Canby    (15') 

204 

USGS  P.P.    492 

1965 

20 

8 

199 

USGS  WSP   338 

1915 

118-119 

Madoc 
4 

196 

CDOG  TR   15 

1975 

29 

1 

198 

CDOG  TR   13 

1975 

47 

19 

Warm  Springs  Valley 

42N 

lOE 

13 

ff> 

Canby    (15') 

ei 

USGS   P.P.    492 

1965 

20 

7 

ei 

USGS  WSP   338 

1915 

119 

Modoc 
5 

Essex   Springs 

42N 

HE 

10 

n> 

Alturas    (15') 

80-92 

USGS  P.P.   492 

1965 

20 

6 

92 

USGS  WSP   338 

1915 

119 

Modoc 
6 

Hot  Creek  Ranch 

42N 

HE 

9 

m 

91 

CDOG  TR   13 

1975 

47 

18 

Spring  near  Canyon 
Creek 

40N 

HE 

227 

m 

Alturas   (15') 

80 

USGS   P.P.   492 

1965 

20 

9 

Location  very  vague 

- 

USGS  WSP   338 

1915 

120 

Modoc 

7 

Spring  near   Alturas 

42N 

13E 

30 

(C 

Alturas    (15* ) 

72 

USGS   P.P.   492 

1965 

20 

10 

Ixscation  vague 

72 

USGS  WSP   338 

1915 

323-324 

HDdoc 
9 

Williams   Ranch  Well 

40N 

13E 

31 

M) 

Alturas    (15'  ) 

110 

114. 

CDOG  TR    15 

1975 

29 

2 

Old  Wllllau  Ranch 
Well 

- 

111 

~ 

CDOG  TR   13 

1975 

47 

22 

S  Appendix  D  for  location 

84 

ALTURAS  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX   B    -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND  WELLS 


• 
KW 

LOC. 

NO. 

NAME 

LOCATICM 

OUADRWlGtE 

WATER 
TEMP. 
CD 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE (S) 

NOTES 

T 

R 

SEC. 

BU< 

PUBLICATION 

YEAR 

PAGE 

LOC. 
HO. 

?1A 

New  Williams  Ranch 
Bell 

40N 

13E 

30 

H) 

Alturas  (15') 

84 

200 

CDOG  TR  13 

1975 

47 

21 

2? 

Warm  spring 

40N 

13E 

31 

M) 

Alturas  (15*) 

75 

FerB.  corm. ,  J.B. 
Koenlg 

23 

Henlo  Warm  Springs 

39N 

17E 

7 

M) 

Eagleville  (Tlj-  ) 

117-125 

USGS  P.P.  492 

1965 

20 

20 

- 

uses  DSP  338 

1915 

123 

Modoc 
16 

Location  vagu« 

Henlo  Baths 

39N 

17E 

6  «  7 

H) 

12B, 
139 

USGS  Geoth.  rtodoc  Co. 
(Open  file) 

1974 

8a 

120 

CDOG  TR  13 

1975 

47 

16 

Menlo  Hot  Springs 

39N 

17E 

7 

VD 

135 

CDOG  TR  15 

1975 

Table 
4a 

6 

24 

Kosk  creek  Hot 
Springs 

37N 

IW 

25-26 

to 

Big  Bend  (15') 

100 

USGS  P.P.  492 

1965 

20 

23 

- 

USGS  WSP  336 

1915 

116-117 

Shasta 

7 

Hunt  Hot  Spring 

37N 

IW 

25 

M) 

136 

CDOG  TR  15 

1975 

29 

7 

Hunt  (Kosk  Creek) 
Hot  Spring 

37N 

IW 

26 

H> 

136 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1966 

27 

F.E.  Rayner,  Jr. 

37N 

IW 

26 

K) 

105 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  S  Klamath  Mtns.) 

1968 

27 

25 

Big  Bend  Hot  Springs 

37N 

IW 

36 

MD 

Big  Bend  (15') 

100-180 

USGS  P.P.  492 

1965 

20 

24 

180 

USGS  WSP  338 

1915 

115-116 

Shasta 

8 

ISO 

USGS  Water  Res.  Div.  Open  File 
{No.  Coast  &  Klamath  Mtns.) 

1966 

27 

2$ 

Little  Hot  Spring 
Valley 

39N 

5E 

9 

H> 

Fall  Fiver  mils 
(15') 

127, 
170 

USGS  P.P.  492 

1965 

20 

11 

Little  Hot  Spring 
Valley 

39N 

5E 

9 

VD 

Fall  River  Mills 
(15') 

127, 
170 

USGS  WSP  336 

1915 

lie 

Modoc 
3 

Little  Hot  Springs 

168 

CDOG  TR  15 

1975 

29 

3 

167-171 

CDOG  TR  13 

1975 

47 

26 

27 

Hot  springs 

37N 

6E 

28  or 
27 

K> 

Fall  River  Hills 
(15') 

7 

Pers.  comm.,  J.B. 
Koenlq,  Q.  Aune 

26 

Bassett  Hot  Springs 

3eN 

7E 

12 

rc 

Bieber  (15') 

173 

USGS  P.P.  49? 

1965 

20 

26 

173 

USGS  WSP  338 

1915 

117 

Lassen 

1 

174 

CDOG  TR  15 

1975 

29 

5 

174 

CDOG  TR  13 

1975 

47 

24 

29 

Stonebreaker  Hot 
Springs 

38N 

BE 

14 

W) 

Bieber  (15') 

110-165 

USGS  P.P.  492 

1965 

20 

29 

165 

USGS  WSP  338 

1915 

117-118 

Lassen 
2 

Kelloq  Hot  Spring 

38N 

BE 

15 

vc 

174 

CDOG  TR  15 

1975 

29 

6 

Kellog  Hot  Spring 

3eN 

8E 

14  »  15 

VD 

172 

CDOG  TR  13 

1975 

47 

25 

30 

Warm  spring 

?9N 

13E 

}} 

«J 

Tule  ntn.  (71i') 

Pers.  conw.,  J.B. 
Ko«nlq  6/71 

11 

Wars  spring 

3aN 

14t 

6 

W) 

Tule  Htn.  (7),'  ) 

70t 

Pers.  coitm.,  'j.B. 
Koerlq  6/-'l 

3? 

West  Volley  Rc6., 
Hot  Spring 

39N 

14E 

29 

H) 

Tule  Htn.  (7),') 

171 

CDOG  TR  15 

1975 

29 

4 

165 

CDOG  TR  13 

1975 

47 

23 

•   S««  Appendix  D  for   location. 


1985 

ALTURAS  SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  85 

APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


LOCATICN 

QUADRANGLE 

VnTER 
TEHP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE (S) 

NOTES 

.^  '              -•"- 

T 

R 

SEC. 

8CM 

sc. 

PUB LI CATION 

YEAR 

PACE 

LOC. 
HO. 

33 

Hot  aisrlltg 

39N 

17E 

M 

K> 

Snak<  Lak«  (7>fl 

120 

uses  P.P.   492 

1965 

20 

21 

- 

USGS  WSP    330 

1915 

123-124 

«D<l0C 
17 

Squaw  Baths  Springs 

39N 

17E 

29 

N> 

95-109 

uses  GeoUl.    Hodoc  Co. 
(Open  file) 

1974 

ea 

3  springs 

OXXi  TR   13 

1975 

47 

17 

34 

&ar«  Ranch 

iSN 

17E 

107 

W 

Snak<  Lake   (7>i') 

70 

USGS  P.P.    492 

1965 

20 

22 

Location  vague 

■ 

USGS  WSP   338 

1915 

124 

Hodoc 

18 

BAKERSFIELD  SHEET 


1 

California   (Deer 
Creek)   Hot  Springs 

22S 

3  IE 

31 

W 

California  Hot 
Springs   (15") 

105- 
126 

USGS   P.P.   492 

1965 

23 

137 

120- 
126 

USGS  HSP    336 

1915 

49-50 

Tulare 

18 

2 

Democrat  Springs 

28S 

31E 

4-5 

lO 

Glennville  (15* } 

100- 
115 

USGS   P.P.   492 

1965 

24 

152 

115 

USGS  WSP    338 

1915 

51-52 

Kem  7 

2A 

Hot  spring 

27S 

3  IE 

33 

m 

Desocrat  (A') 

1 

USGS  Democrat  7H'    quad. 

1972 

3 

Delcnegha  Springs 

27S 

31E 

26 

H> 

Glennville   (15*) 

104- 
112 

USGS  P.P.   492 

1965 

24 

151 

USGS  WSP   338 

1915 

51 

Kem  8 

4 

Clear  Cre«k    (Hobo) 
Hot  Sprlr.gs 

27S 

32E 

15 

fC 

Glennville   (15') 

119 

USGS  P.P.   492 

1965 

24 

150 

Clear  Creek  (Hobo) 
Hot  Springs 

27S 

32E 

15 

HI 

Glennville  (15') 

USGS  WSP   338 

1915 

51 

Kem  9 

5 

Miracle  Hot  Springs 

27S 

32E 

15 

M) 

Glennville  (15') 

7 

USGS  Glennville  IS'   quad. 

6 

Nellls  Hot   Spring 

35-37. 2'N 

11S-2S.6'M 

Isabella  (15') 

131 

USGS  P.P.   492 

1965 

24 

149 

Shown  as  Scovem  Hot 

131 

USGS  WSP   336 

1915 

51 

Kem  10 

quad. 

7        Hot   spring 

35*43. 7'N 
118*24. e'K 

Isabella    (15- ) 

96 
113 

USGS   P.P.   492 

1965 

24 

148 

103 

USGS  WSP   338 

1915 

50 

Kem  11 

6 

MllUaK  Hot  Springs 

29S 

33E 

6 

K> 

Emerald  Htn. 
(15') 

60-100 

USGS  P.P.   492 

1965 

24 

153 

Shown  as  Yates  Hot 
Springs  on  1943  topo 
quad. 

97 

USGS  WSP   338 

1915 

52 

Kem  17 

CHICO  SHEET 


1 

2 

Doyle  Hot   Springs 

24N 

12E 

24 

H> 

Blairsden    (15') 

106 

CDOG  TR   13 

1975 

47 

34 

tfcLear  Sulphur  Spring 

22N 

13E 

32 

H) 

Sierra  City 
(15') 

66 

USGS  P.P.   492 

1965 

21 

42 

84-86 

USGS  WSP   338 

1915 

283-284 

Plusias 
15 

McLear's  Warn  Springs 

86 

CDOG  TK   13 

1975 

48 

46 

3 

rterble  Hot  wells 

22« 

14E 

13 

ff> 

Portola   (15'  ) 

125- 
161 

USGS  P.P.   492 

1965 

21 

41A 

125- 
161 

350 

1885- 
1888 

USGS  WSP  338 

1915 

128-129 

Pluauis 
16 

Also  springs— 87" 

S*«  Appendix  D  for  location. 


86 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


CHICO   SHEET 


APPENDIX   B   -    TABULATED   LIST   OF    THERMAL   SPRINGS   AND   WELLS 


7\ 

MAP 

LOC. 
NO. 

NAME 

L.OCATICM 

QUADRANGLE 

WATER 
TEMP. 

CF) 

TOTAL 
DEPTH 
(FEET) 

1 ■ 

YEAR 
DRILLED 

REFERENCE (S) 

, 

NOTES 

T 

R 

SEC. 

But 

PUBLICATIOW 

YEAR 

PACE 

LOC. 
NO. 

' 

Marble  Hot  Springs 
Mils 

22N 

i4e 

13 

M) 

Portola  (15' 1 

1  sa- 
les 

330 

CDOG   TR  15 

1975 

11 

1.  2 

158- 
163 

330 

CDOG  TR  13 

1975 

48 

35,  36 

4 

vlsclB  Well 

22(1 

14E 

25 

K) 

Sierraville  (15- 1 

104 

25 

aiOG  TF.  I  ' 

1975 

48 

37 

5 

Shallow  Well 

22N 

15E 

26 

rc 

Slerraville  (15'  ) 

131 

CDOG  TR  1 3 

1975 

48 

18 

6 

w.  Hagge  Well  (1) 

'J2N 

15E 

Mr. 

Sierraville  (15' ) 

104 

699 

CDOG  TR  15 

1975 

11 

3 

Haqge  Well  1 

104 

CDOG  TR  13 

1975 

48 

39 

\ 

7 

w.  Hagge  well  (?) 

?2N 

ISE 

32 

HD 

Sierraville  Wj''! 

102 

597 

CDOG  TR  15 

1975 

11 

4 

Ha9ge  Well  2 

102 

CDOG  TR  13 

1975 

48 

40 

8 

w.  Haqqe  Well  (3) 

221J 

15E 

32 

HD 

Sierraville  (15') 

111 

699 

CDOG  TR  15 

1975 

11 

6 

Hagge  Well  3 

126 

909 

CDOG   TR  13 

1975 

48 

41 

9 

G.  Fllipinl  Well  111 

2  2N 

15E 

'•■ 

M' 

Sierraville  (15') 

201 

1099 

CDOG  TR  15 

1975 

11 

5 

Filipinl  Well  1 

201 

1080 

CDOG  TR  13 

1975 

48 

42 

10 

G.  Fillpini  Well  (2) 

21N 

15E 

t-lD 

Sierraville  (15-) 

CDOG  TR  15 

1975 

11 

7 

Fillplnl  Well  2 

124 

399 

CDOG  TR  13 

1975 

48 

43 

11 

Fillpini  Well  3 

21N 

15E 

5 

rc 

Sierraville  (15') 

111 

600 

CDOG  TR  13 

1975 

48 

44 

12 

Campbell  Hot  Springs 

20N 

15E 

19 

m 

Sierraville  (15') 

65-111 

USGS  P.P.  492 

1965 

21 

43 

Campbell  Hot  Springs 

20N 

15E 

19 

HD 

Sierraville  (15') 

98-111 

USGS  WSP  338 

1915 

129-130 

Sierra  1 

100 

CDOG  TR  15 

1975 

11 

9 

99-111 

CDOG  TR  13 

1975 

48 

45 

13 

Brockway  Hot  Springs 

16N 

ISE 

30 

MD 

Tahoe  (15' ) 

120-140 

USGS  P.P.  49; 

1965 

21 

44 

137 

USGS  WSP  33B 

1915 

131 

Placer  8 

131 

CDOG  TR  13 

1975 

48 

47 

Near  Kinqs  Beach 

14 

Wentworth  Springs 

14N 

15E 

31 

W3 

Granite  Chief 
(15') 

60-75 

USGS  P.P.  492 

1965 

21 

44A 

USGS  WSP  338 

1915 

235-236 

Eldorado 

7 

Carbonated  springs 

DEATH   VALLEY    SHEET 


1 

Spring  In  Saline 
Valley 

13S 

39E 

le 

PC 

Waucoba  Wash 
(15') 

100 

USGS  P.P.  492 

1965 

23 

139 

warm 

USGS  WSP  338 

1915 

136 

Inyo  12 

Lower  warm  Spring 

110 

USGS  WRI  33-73 

1974 

10 

90 

Also  lenown  as 
Burro  Warm  Springs 

2 

Palm  Springs 

13S 

39E 

le 

W) 

Waucoba  Wash 
(15') 

120 

USGS  WRI  33-73 

1974 

10 

91 

3 

Upper  Warm  Spring 

13S 

39E 

9 

W) 

Dry  Mtn.  (15') 

USGS  Dry  Mtn.  15'  quad. 

1957 

4 

Keenr  wonder  Spring 

15S 

46E 

I 

rt) 

Chloride  Cliff 
(15') 

8- 

USGS  P.P.  44ri 

1963 

54 

1        r.-pn.,ltlr,.l 
travertlnp 

•  Se«  Appendix  D  for  location. 


1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  87 

DEATH  VALLEY    SHEET  APPENDIX   B    -    TABULATED    LIST   OF    THERMAL    SPRINGS   AND  WELLS 


HAP 
LOC. 
HO. 

NAME 

LOCATICW 

QUADRANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 

DRILLED 

REFEra:NCE(S) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATK* 

YEAR 

PAGE 

LOC. 
NO. 

4 
5 

ice«ne  Morder  Spring 

15S 

46E 

1 

PC 

Chloride  Cliff 
(15') 

90-93 

USGS  P.P.   492 

1965 

23 

140A 

Dirty  Socks  -Hot 
Spring- 

les 

37E 

34 

rc 

Ke«ler    (IS-  ) 

7 

600 

1917 

CTHG  ms  vol.    17  no.    U 

Nov. 
1964 

202 

6 

Hot  sprlng-fumarole 

2?S 

38E 

i; 

re 

Halwe*   Rm.    (15') 

150-2C3 

uses  P.P.   492 

1965 

23 

141 

7 

D»vHs  Kltcho. 

(fUMTOle) 

25S 

39E 

7 

ro 

Halwee  Rea.    (IS-  ) 

180   to 
bolllrg 

USGS  P.P.    492 

1965 

23 

141A 

203 

USGS  WSP   338 

1915 

150-151 

Inyo   30 

206 

USGS  WRI    33-73 

1974 

6 

14 

8 

Coso  Hot  Springs 

22S 

39E 

4 

N> 

Halw««  Res.    (IS- ) 

140   to 
boiling 

\JSGS  P.P.    492 

1965 

23 

U? 

USGS  WSP   338 

1915 

149-150 

Inyo  31 

Mil 

207 

106 

USGS  WU   33-73 

1974 

6 

12 

WU 

240 

375 

USGS  WI   33-73 

1974 

6 

13 

9 

war»  sprir.a 

21S 

44E: 

10 

PC 

Telescope  Pk. 
115-I 

80 

USGS  P.P.    492 

1965 

24 

144 

Shown   as  Warm 
Sulphur   Springs  on 
1952   topo.    quad. 

USGS  WSP   338 

1915 

136 

Inyo   29 

EL  CENTRO    SHEET 


1 

C.L.  S«lth  Well 

16S 

lOE 

5 

SB 

Painted  Gorge 

85 

150 

Rex  unpub. 

1972 

4 

-- 

2 

J.   Green   Well 

16S 

lOE 

16 

SB 

Painted   Gorge 
(TiiM 

85 

105 

Rex  unpub. 

1972 

4 

161A 

3 

Dolllnger  Well 

16S 

lOE 

16 

SB 

Painted  Gorge 
(71,') 

86 

300 

Rex  unpub. 

1972 

4 

162 

4 

KaqaM   Er.erc>'   Co. 
Bonanza   1 

15S 

14E 

22 

SB 

El  Centre  (Tlj*) 

5024 

1973 

Werner  unpub. 

1973 

Map 

28 

5 

well 

15S 

15E 

le 

SB 

Holtville  West 

100 

USGS  WRI   33-73 

1974 

8 

57 

6 

N.  rifleld  Well 

14S 

15E 

6 

SB 

Alamorio  <7)j'  ) 

124 

1250 

CDOG  TR   15 

1975 

Table  la 

17 

129 

1290 

Rex  unpub. 

1972 

1 

64 

7 

T.   Shank  well 

13S 

15E 

32 

SB 

AlajTorio   iTH'  ) 

111 

1006 

(DOG  TB    15 

1975 

Table  la 

12 

8 

Maiaer-Shank  well 

14S 

15E 

9 

SB 

Alanorio  (7^5'  ) 

88 

800 

Rex  unpub. 

1972 

3 

144 

9 

J.  Blrger  Well 

145 

15E 

9 

SB 

Alamorlo   (71,') 

89 

385 

Rex  unpub. 

1972 

3 

42 

88 

387 

CDOG  TH   15 

1975 

Table   la 

18 

10 

Ha^wlla  School   Well 

13S 

15E 

33 

SB 

AlMnorlo  (TT) 

124 

1337 

OXIG  TB   15 

1975 

Table  la 

13 

11 

127 

1389 

Rex  unpub. 

1972 

1 

1 

M.    Pheglev  Well 

13S 

ISE 

34 

SB 

Alamorlo  (T",'  ) 

111 

950 

CDOG  TR    15 

1975 

Table  la 

14 

Rutherford  Well 

112 

954 

Rex  unpub. 

1972 

1 

4 

12 

rifleld   Wei! 

135 

15E 

34 

SB 

Alajoorlo   (7»j') 

112 

1045 

Rex   unpub . 

1972 

1 

111 

13 

Orlta   Stage   Station 
Well 

13S 

15E 

34 

SB 

AlsBorlo   (T<j') 

110 

900 

Rex  unpub.                                                1  ^"2 

1 1 

1 

7 

S*«  Appendix  D  for  locAtion. 


88 

EL  CENTRO  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX   B   -    TABULATED   LIST   OF   THERMAL    SPRINGS   AND  WELLS 


• 
MAP 

LOC. 

NO. 

NAKE 

LOCATION 

QUADRANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 

DRILLED 

REFERENCE  (S) 
(see  list  of  references  for  abbreviations) 

NOTES 

T 

R 

SEC. 

BtM 

PUBLICATION 

YEAR 

PAGE 

LOC. 

NO. 

14 

md1o1«  rtta  Lot  well 

(Same  as  No.  51?) 

14S 

15E 

11 

SS 

Alamorlo  (71}') 

107 

654 

CDOG  TR  15 

1975 

Table  la 

19 

15 

A.  Glslf^r  Well 

l.iS 

15E 

15 

SB 

Alamorlo  n^'  ) 

117 

1172 

CDOG  TP  1' 

1975 

Table  la 

21 

Gisler-Bowman  Well 

121 

1165 

Rex  unpub. 

1972 

1 

35 

16 

Hendlburu  Feed  Lot 
Well 

14S 

15E 

12 

SB 

Alamorlo  (75j*) 

125 

1240 

CDOG  TR  15 

1975 

Table  la 

20 

K-F  Feed  Let  Acll 

124 

1260 

Rex  unpub. 

1972 

1 

43 

n 

OKXTTED 

18 

J.  Blrger  Well 

US 

15E 

23 

SB 

Alamorlo  (71i') 

103 

754 

CDOG  TR  15 

1975 

Table  la 

22 

Janes  Blrger  Sr.  Well 

106 

750 

Rex  unpub. 

1972 

I 

34 

19 

J.  Birgec  Well 

14S 

15E 

27 

SB 

Alamorlo  (7H' ) 

90 

402 

CDOG  TR  15 

1975 

Table  la 

23 

James  Blrqer  Jr.  Well 

90 

400 

Rex  unpub. 

1972 

3 

33 

20 

A.  Foster  Well 

14S 

15E 

2B 

SB 

Alamorlo  C75j'  ) 

86 

380 

Rex  unpuh. 

1972 

3 

143 

21 

Jenson  Well 

145 

15E 

34 

SB 

Alamorlo  171)'  ) 

86 

359 

CDOG  TR  15 

1975 

Table  la 

24 

22 

Gaddls  Well 

14S 

15E 

34 

SB 

Alamorlo  (7Ji'  ) 

96 

613 

CDOG  TR  15 

1975 

Table  la 

25 

23 

Gaddls-Hanson  Well 

145 

15E 

34 

SB 

Alamorlo  <7!jM 

97 

610 

Rex  unpub. 

1972 

^ 

31 

24 

Shawner  Well 

155 

15E 

10 

SB 

Holtvllle  West 
(7),M 

90 

463 

CDOG  TR  15 

1975 

Table  la 

32 

Shawner-Harmon  Well 

90 

460 

Rex  unpub. 

1972 

3 

25 

25 

F.  Shaffner  well 

15S 

15E 

9 

SB 

Holtvllle  West 
(71,') 

69 

550 

Rex  unpub. 

1972 

3 

41 

26 

A.  Barnes  Well 

155 

15E 

10 

5B 

Holtvllle  West 
(71,') 

90 

399 

Rex  unpub. 

1972 

3 

30 

21 

C.  Aller,  .^eU 

15S 

15L 

14 

SB 

Holtvllle  West 
(71,') 

104 

864 

Rex  unpub. 

1972 

1 

24 

104 

869 

CDOG  TR  15 

1975 

Table  la 

33 

2S 

K.  Sharp  well 

15S 

15E 

13 

SB 

Holtvllle  West 
(71,') 

97 

800 

Rex  unpub. 

1972 

2 

145 

29 

J.  DePaoll  Well 

15S 

15E 

26 

SB 

Holtvllle  West 

104 

954 

CDOG  TR  15 

1975 

Table  la 

34 

106 

970 

Rex  unpub. 

1972 

1 

11 

30 

Hodem  Grocery  Well 

15S 

15E 

25 

SB 

Holtvllle  West 
(71,') 

96 

850 

Rex  unpub. 

1972 

'- 

14 

31 

Holtvllle  Ice  Co. 
Well 

15S 

15E 

35 

SB 

Holtvllle  West 
(7),') 

113 

1100 

Rex  unpub. 

1972 

1 

8 

CDOG  »t35 

32 

City  of  Holtvllle 
Well 

15S 

15E 

36 

SB 

Holtvllle  West 
(7>,') 

84 

850 

CDOG  TR  15 

1975 

Table  la 

36 

Unnamed  well 

155 

15E 

36 

SB 

109 

14 

USG5  WRt  33-73 

1974 

e 

56 

33 

Haiz  Strar^g  Well 

15S 

15E 

25 

SB 

Holtvllle  East 
(71,') 

112 

673 

Rex  unpub. 

1972 

1 

150 

34 

Spanish  Trails  Mobil 
Home  Park  Well 

15S 

16E 

30 

SB 

Holtvllle  East 
(71,') 

110 

1551 

Rex  unpub. 

ll?.-! 

1 

17.' 

35 

A.  PuBl,  Jr.  Well 

15S 

16E 

30 

SB 

Holtvllle  East 
(71,M 

104 

918 

CVOG   TR  15 

1975 

Table  la 

44 

104 

1000 

Rex  unpub. 

1972 

I 

62 

36 

A.  Fual.  Well 

15S 

16E 

29 

SB 

Holtvllle  East 
(71,') 

87 

580 

CDOG  Tf-  l'. 

1975 

Table  la 

43 

•   S««  Appendix  D  for   location. 


1985 

EL   CENTRO    SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


89 


APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


HAP 
LOC. 
NO. 

name: 

LOCATICW 

QUADRANGLE 

WATER 
TEMP. 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 

NOTES 

T 

R 

SEC. 

BIM 

PUBLICATION 

YEAR 

PAGE 

IOC. 
NO. 

36 

37 

A.  Fusl,  Sr.  Well 

ISS 

leE 

J9 

5B 

HoltvUle  Enst 

88 

616 

Rex  unpub. 

1972 

3 

16 

F.  Strahm  Well 

I5S 

UE 

10 

5B 

Holtvllle  East 

97 

839 

CDOG  TR  15 

1975 

Tabic  In 

40 

38 

98 

834 

Rex  unpuh. 

1972 

2 

21 

Hooke  Well 

15S 

l&E 

7 

5b 

Holtvllle  bast 
US') 

97 

663 

CLOG  TR  15 

1975 

Table  la 

37 

H.  Hoke  Well 

99 

695 

Rex  unpub. 

1972 

2 

28 

39 

G.  Hoyt  Well 

15S 

16E 

8 

SB 

Holtvllle  East 
(A') 

89 

484 

CDOG  TR  15 

1975 

Table  la 

38 

89 

488 

Rex  unpub. 

1972 

3 

27 

40 

F.  Grlnello 

15S 

15E 

12 

SB 

Holtvllle  East 

101 

Rex  unpub. 

1972 

2 

146 

106 

USGS  WRI  33-73 

1974 

10 

59 

41 

J.  Rohret  Well 

15S 

15E 

1 

SB 

Alamorlo  N.E. 
<7liM 

100 

580 

Rex  unpub. 

1972 

2 

147 

47 

A.  Iitmel  Well 

14S 

16E 

19 

SB 

Alamorlo  N.E. 
(7I5M 

124 

1135 

Rex  unpub. 

1972 

1 

157 

43 

F.  Axler  Well 

14S 

16E 

Jl 

SB 

Alamorio  N.E. 

96 

450 

Rex  unpub. 

1972 

2 

154 

44 

5.  Stacey  Well 

14S 

16E 

21 

SB 

Alamorlo  N.E. 

88 

450 

Rex  unpub. 

1972 

3 

38 

90 

440 

CDOG  TR  15 

1975 

Table  la 

30 

4S 

Singh  Well 

145 

16E 

22 

SB 

Alamorio  N.E. 
(7I,M 

96 

709 

Rex  unpub. 

1972 

2 

39 

117 

USGS  WRI  33-73 

1974 

8 

58 

Singh  Well 

14S 

16E 

22 

SB 

Alamorlo  N.E. 
(71,.) 

107 

706 

CDOG  TR  15 

1975 

Table  la 

31 

46 

Chopenlck  well 

145 

16E 

16 

SB 

Alamorlo  N.E. 
(71,') 

90 

450 

Rex  unpub. 

1972 

3 

155 

2  separate  wells 

K.  Axler  well 

78 

402 

CDOG  TR  15 

1975 

Table  la 

29 

47 

F.  Borchard  Well 

14S 

16E 

4 

SB 

Alamorio  N.E. 

102 

456 

Rex  unpub. 

1972 

2 

47 

100 

425 

CDOG  TR  15 

1975 

Table  la 

26 

48 

F.  Borchard  Well 

145 

16E 

4 

SB 

Alamorio  N.E. 
(7!,') 

102 

457 

Rex  unpub. 

1972 

2 

46 

101 

460 

CDOG  TR  15 

1975 

Table  la 

27 

49 

B.  EAaruelU  Well 

135 

16E 

32 

SB 

Alamorio  N.E. 
I7!,M 

106 

Rex  unpub. 

1972 

1 

112 

50 

Q.O.  Cattle  Co.  Well 

135 

16E 

28 

SB 

Alamorio  N.E. 

98 

Rex  unpub. 

1972 

2 

156 

51 

Moiola  Feed  Lot  Well 

145 

16E 

11 

SB 

Alamorio  N.E. 
(71j'l 

108 

650 

Rex  unpub. 

1972 

1 

45 

52 

U.S.G.S.  casts  well 

145 

16E 

11 

SB 

Alamorio  N.E. 
(7>,.) 

96 

287 

Rex  unpub. 

1972 

2 

65 

53 

U.S.-B.L.M.  Well 

145 

16E 

11 

SB 

Alamorio  N.E. 

lA'l 

94 

287 

CDOG  TR  15 

1975 

Table  la 

28 

54 

Coons  Well 

14S 

16E 

27 

SB 

Alamorio  N.E. 
(71,M 

88 

Rex  unpub. 

1972 

3 

148 

5S 

A.  Jechlms  Wells 

145 

16E 

34 

SB 

Alamorio  N.E. 
(71,'> 

92 

Rex  unpub. 

1972 

3 

149 

56 

R.  Garewal  well 

155 

16E 

15 

SB 

Holtvllle  East 
(71jM 

91 

800 

Rex  unpub. 

1972 

3 

23 

90 

804 

CDOG  TR  15 

1975 

Table  la 

39 

See  Appendix  D   (or   location. 


90 

EL  CENTRO  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX   B   -    TABULATED   LIST   OF   THERMAL    SPRINGS   AND   WELLS 


• 
HAP 

LOC. 

HO. 

HAKE 

LOCATICW 

QOADRANGLE 

WATER 
TEMP. 
CFl 

TOTAI. 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFEREMCE(S) 

BOTES 

T 

R 

SEC. 

B£M 

PUBLICATICM 

YEAR 

PAGE 

LOC. 
NO. 

57 

0.  St«rr  Hell 

15S 

16E 

22 

SB 

Holtvllle  East 
<71,M 

98 

750 

Rex  unpub. 

1972 

2 

20 

94 

754 

COOG  TR  15 

1975 

Table  la 

41 

58 

L.  Foster  well 

15S 

16£ 

23 

SB 

Holtvllle  East 
{7l)'  ) 

95 

561 

Rex  unpub. 

1972 

2 

IB 

94 

544 

CBOG  TR  15 

1975 

Table  la 

42 

59 

Neldlf(er  well 

15? 

I6F 

27 

SB 

Holtvllle  East 
(71,') 

89 

600 

Rex  unpub. 

1972 

3 

17 

60 

C.  An«lel  well 

165 

16£ 

4 

SB 

Holtvllle  East 
(73,- ) 

102 

940 

Rex  unpub. 

1972 

2 

61 

94 

944 

CDOG  TR  15 

1975 

Table  la 

45 

61 

Date  City  Store  Well 

16S 

i6e 

3 

SB 

Holtvllle  East 
(7),M 

89 

596 

Rex  unpub. 

1972 

3 

133 

62 

Hagpia  energy  Inc. 
Sharp  *1 

155 

16£ 

35 

SB 

Holtvllle  East 
(7l,M 

6070 

1972 

Werner  unpub. 

1973 

Map 

17 

259 

6072 

USGS  Open  File 
(Imperial  Valley) 

1976 

26 

215 

63 

techuqa  Store  well 

16S 

16E 

17 

SB 

Holtvllle  East 
(7),M 

104 

Rex  unpub. 

1972 

1 

136 

64 

Alano  School  Well 

165 

16£ 

15 

SB 

Holtvllle  East 

99 

lOOO 

Rex  unpub. 

1972 

2 

29 

65 

Hasserinl  well 

165 

16E 

15 

SB 

Holtvllle  East 
(Tl,') 

107 

1060 

Rex  unpub. 

1972 

1 

36 

Alaao  School  (ABD.) 
Well 

100 

881 

CDOG  TR  15 

1975 

Table  la 

47 

Old  Alano  Store  Well 

lis 

1177 

Rex  unpub. 

1972 

1 

26 

66 

watton  Labor  Camp 
Well 

165 

16E 

14 

SB 

Holtvllle  East 
(7>C) 

112 

800 

Rex  unpub. 

1972 

1 

15 

watton  Labor  Camp 
Well 

16S 

16E 

14 

SB 

Holtvllle  East 

109 

1134 

CDOG  TR  15 

1975 

Table  la 

46 

67 

Schnelder-Gothrle 
Well 

165 

16E 

12 

SB 

Holtvllle  East 
(71,M 

106 

825 

Rex  unpub. 

1972 

1 

137 

6e 

Under  Gravel  Well 

165 

16E 

13 

SB 

Holtvllle  East 

120 

810 

Rex  unpub. 

1972 

1 

134 

69 

U.S.B.R.  06-151  Well 

165 

17E 

6 

SB 

Glamls  SW  (7!,M 

91 

150 

Rex  unpub. 

1972 

3 

170 

70 

U.S.B.B.  Mesa  6-1 
well 

165 

17E 

6 

SB 

GlarUs  SW  (7!iM 

6030 

1972 

Werner  unpub. 

1973 

Map 

27 

395 

7960 

U5<a  Open  File 
(Imperial  Valley) 

1976 

30 

336 

70A 

U.S.B.R.  Mesa  6-2 
Well 

165 

17E 

6 

SB 

Glamls  SW  (fljM 

6005 

1973 

Werner  unpub. 

1973 

Hap 

31 

368 

5920 

USGS  Open  File 
(Imperial  Valley) 

1976 

30 

339 

71 

U.C.  Rlverslde-127 
Well 

165 

17E 

17 

SB 

Glamls  5W  i^>,^  ) 

181 

1500 

Rex  unpub. 

1972 

1 

71,  71A 

186 

1363 

USGS  Open  File 
(Imperial  Valley) 

1976 

30 

348 

7J 

U.S.B.K.  Mesa  5-1 
Well 

165 

17E 

5 

SB 

Glamls  SW  ITS' ) 

6000± 

1974 

Werner  unpub. 

1973 

Hap 

34 

73 

S.llh  Bros,  .-n 

135 

16E 

33 

SB 

Clanls  (15*) 

160 

680 

Rex  unpub. 

1972 

1 

171 

74 

U.S.B.R.-U.C.R.  »115 

155 

I9e 

33 

SB 

Glamls  (15') 

212. 

350 

1971 

CDWR-UCR  Dunes  Report 

1973 

3,  8,  9 

DHR  Dimes  «1  Well 

21 2± 

leoot 

1972 

CDWR-UCR  Dunes  Report 

1973 

3,  8,  9 

DWR  Dunes  Kl  Well 

2007 

1972 

Werner  unpub. 

1973 

Hap 

18 

75 

E.rBa  Hire  xcl  1 

ns 

19E 

33 

SB 

Oqlbley  (15* ) 

66 

700 

Rex  unpul  . 

1972 

4 

&••  Appendix  D  for   location . 


1985 

EL   CENTRO    SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  91 

APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


• 
HAP 

UX. 

SO. 

NAME 

LOCATICW 

QUADRANCIZ 

WATtJR 
TEMP. 
CF) 

T^rAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATIOH 

YEAR 

PAGE 

LOC. 
NO. 

■>(, 

Gold   Rock   Ranch  Well 

15S 

20E 

7 

SB 

Oqlbley  (15M 

98 

690 

Rex  unpub. 

1972 

2 

13 

77 

Texaco  1-8  Well, 
Ii^)«rlal  Hwy. 

l&S 

9E 

36 

SB 

Coyote  Wella 
17',M 

91 

547 

Rex   unpub. 

1972 

3 

7S 

85 

312 

Rex  ixipub. 

1972 

4 

" 

78 

w.   Slnpsor^   Well 

ns 

loe 

11 

SB 

Coyote  Wells 
(7l,.> 

85 

302 

Rex  unpub. 

197? 

4 

fi? 

79 

Ns^a  Energy,    Inc. 
Fed-Rlte  wl  Well 

17S 

HE 

8 

SB 

Ht.  Si^al    (71,') 

5380 

1973 

Werner  unpub. 

1973 

Hap 

30 

80 

na^a  Energy,    Inc. 
Holtz  aZ  well 

16S 

HE 

31 

SB 

Heber  (71,') 

5000 

1972 

Werner  unpub. 

1973 

Map 

?0 

318 

4890 

USGS  Open  File 
(Imperial   valley) 

1976 

30 

302 

ei 

Nagaa  Energy,    Inc. 
Molti  #1  Well 

16S 

14C 

32 

SB 

Heber  (7>iM 

5147 

1972 

WerTier  unpub. 

1973 

l«p 

19 

3  34 

5025 

OSGS  Open  File 
llmperlal  Valley) 

1976 

30 

304 

62 

Chev«»i  Oil  Co. 
Nowlln   Fart.    1   Well 

l&S 

14E 

33 

SB 

Heber  (T!,') 

50  30 

1972 

Werner  unpub. 

1973 

Map 

21 

83 

L.   Bomt  well 

ns 

16E 

9 

SB 

Bonds  Comer 

95 

714 

Rex  unpub. 

1972 

2 

63 

100 

714 

oxx:  TB  15 

1975 

Table  la 

48 

B4 

hets  Feed  Lot  Well 

16S 

16E 

33 

SB 

Bonds  Comer 
(71,'l 

87 

soo 

Rex  unpub. 

197? 

4 

135 

85 

rb^u  Energy,    Inc. 
Sharp  «2  Well 

16S 

leE 

34 

SB 

Bonds  Comer 

6465 

1973 

Werner  unpub. 

1973 

Hap 

29 

FRESNO  SHEET 


MAP 
LOC. 
NO. 

NAME 

LOCATICW 

WATER 
TEMP. 

TOTAL 
DEPTH 
(FEET) 

VEAR 
DRILLED 

REFERENCE  (S) 
(see   list   of   references    for   abbreviations) 

NOTES 

T 

R 

SEC. 

B&H 

PUBLICATION 

IfEAR 

PAGE 

LOG. 
NO. 

1 

Kem   (Jordan)   Hot 
Spring 

36* 28.7 -N 
118»24.2'W 

Kem  Peak   (15M 

95-123 

USGS    P.P.    492 

1965 

23 

135 

95-123 

USGS  WSP   338 

1915 

53-54 

Tulare  7 

2 

Cn   S.   Fork  of   M.   Fort 
of   Tule   R. 

36*09. 2'N 

llB"39.e'M 

Caa^  Nelsor.    (15') 

77 

USGS   P.P.    492 

1965 

23 

134 

Water  carbonated 

77 

USGS  WSP   338 

1915 

242-243 

Tulare 
11 

■3 

Kmache   neadows 

20s 

35E 

3 

K> 

Hanache  Htn. 
(15') 

100 

USGS  P.P.   492 

1965 

23 

136 

Water   carbor.ated 

USGS  WSP   338 

1915 

246 

Tulare  8 

KINGMAN  SHEET 


No  thenwl  springs  or  wells  reported. 

1 

LONG  BEACH  SHEET 


1 

Unnaaed  warv  springs, 
Malaga  Cove  area. 

4S 

15W 

36 

SB 

Redondo  Beach 
(A-l 

77 

Torrance  Dally  Breeze 

1970 

9 

Jan.   23,    1970, 
newspaper 

2 

Whites   Point   Hot 
Springs 

5S 

14W 

31 

SB 

San  Pedro  (15*) 

114 

USGS  WRJ    3)-71 

1974 

10 

92 

3 

Segura  Fetrol«»  Co. 
Se^a   SI 

5S 

UW 

34 

SB 

Seal  Beach    (7>,') 

425 

8340 

1920's 

CDOG  Huntington   Beach   Map 
No.    134 

COCG  wrltter.   coaa. 
7/26/74 

4 

HcCasden  Well 

6S 

UW 

10 

SB 

Seal  Beach   (7)j'  ) 

very 
hot 

CDOG  written   coawi. 
7/26/74 

•  See  Appendix  D  for  location. 


92 

LOS  ANGELES  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND  WELLS 


• 
HAP 

UK. 

NO. 

NAME 

LOCATIOM 

QUADRANGLE 

HATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE (S) 

NOTES 

T 

R 

SEC. 

BIM 

PUBLICATION 

YEAR 

PACE 

LOC. 
NO. 

1 

San  Hbtcos  Hot  Springs 

5N 

J9W 

2 

SB 

lalce  Cachuma 
(7>,') 

69-108 

USGS   P.P.  492 

1965 

22 

102 

(Mtn.  Glen,  Hot 
Springs) 

■ 

uses  USP  338 

1915 

67-68 

Sta.  Bar. 
2 

(Cuyama  Hot  Springs) 

110 

USGS   Water  Res.  Div.  Open  Pile 
(So.  Coast,  Transv.  I   Penin. 
Ranges) 

1968 

A-16 

2 

Agua  Callente  (Big 
C«ll«nte)  Spring 

5N 

26V 

1 

SB 

Hlldreth  Pea)< 
(7S') 

133 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A-16 

3 

War*  spring 

5N 

25W 

4 

SB 

Hildreth  Peajc 
(71,') 

90 

USGS  P.P.  492 

1965 

22 

104 

4 

Hax«  spring 

5N 

2iV 

1 

SB 

Old  Han  Mtn. 
(7>,M 

90 

USCiS  P.P.  492 

1965 

22 

105 

5 

Wheelers  Hot  Springs 

34*30. 5'N 
119'17.4'W 

Wheeler  Springs 
(7!,M 

62-102 

USGS  P.P.  492 

1965 

23 

109 

102 

USGS  WSP  338 

1915 

64-66 

Ventura 
2 

94,  102 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A-18 

6 

Wlllett  Hot  Springs 

SN 

20V 

30 

SB 

Topatops  Mtn. 
(7!,-) 

120 

USGS  P.P.  492 

1965 

23 

110 

108 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A-19 

7 

Sesp«  Hot  Springs 

ex 

20W 

21 

SB 

Devils  Heart  Pie. 
(7!,'l 

191 

USGS  P.P.  492 

1965 

23 

111 

194 

US(>S  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Poiin. 
Ranges) 

1968 

A-19 

191 

USGS  WSP  338 

1915 

66 

Ventura 

1 

191 

USGS  WRI  33-73 

1974 

10 

87 

8 

Elizabeth  Lake  Canyon 
wami  Spring 

6N 

16W 

15 

SB 

Warm  Springs  Mtn. 
(71,M 

100 

USGS  P.P.  492 

1965 

23 

112 

Elizabeth  IjUce  Canyon 
Wanri  Spring 

6N 

16W 

15 

SB 

Warm  Springs  Mtn. 
(71,.) 

~ 

USGS  WSP  338 

1915 

66 

Los 
Angeles 

1 

92 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A- 7 

9 

Tecolate  Tvjnnel 

5N 

29W 

26 

SB 

Dos  Pueblos  Can. 
(71,') 

93 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Per.ln. 
Ranges) 

1968 

A-16 

10 

Honteclto  (Santa 
Barbara)  Hot  Springs 

4N 

26W 

5 

SB 

Santa  Barbara 
(71,') 

111-118 

USGS  P.P.  492 

1965 

22 

103 

m-iie 

USGS  WSP  338 

1915 

66-7 

Sta.  Bar. 
7 

lie 

USGS  WRI  33-73 

1974 

10 

86 

Monteclto  Hot  Springs 
and  Arsenic  Springs 

4N 

26W 

5  S  6 

SB 

111. 

112 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A- 15 

Arsenic  Springs  in 
Section  6 

11 

Vlckers  Hot  Springs 

34'30.1-N 
119'?0.75'W 

Wheeler  Springs 
(Tlj'  ) 

118 

USGS  P.P.  492 

1965 

22 

106 

" 

USGS  WSP  338 

1915 

62-63 

Ventura 

3 

12 

Stlngleys  Hot  Springs 

5N 

24W 

24 

SB 

Matlll)o  (71,') 

100 

USGS  P.P.  492 

1965 

22 

107 

100 

USGS  WSP  338 

1915 

63 

Ventura 

5 

G.A.  Rice 

123 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A-19 

13 

Katlll]a  Hot  Springs 

SN 

J3W 

29 

SB 

Matili]a  (7),'  ) 

116 

USGS  P.P.  492 

1965 

23 

108 

116 

USGS  WSP  338 

1915 

63 

Ventura 

7 

109 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  t  Penln. 
Ranges) 

1968 

A-19 

14 

Sewlnole  Hot  Springs 

IS 

lew 

5 

SB 

Point  Dume  (TS") 

114 

3000± 

USGS  Water  Res.  Div.  (5pen  File 
(So.  Coast,  Transv.  ft  Penln. 
Ranges ) 

1968 

A--' 

Oil  teat  well 

•   S««  Appondix  0  for  location. 


1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  93 

LOS   ANGELES    SHEET  APPENDIX   B   -    TABULATED    LIST   OF    THERMAL    SPRINGS   AND  WELLS 


• 
HAF 

LOC. 

NO. 

NAMt- 

LCCATItli 

OUADRANGLE 

WATER 
TEMP. 
{*F) 

TOTAL 
DEPTH 
(FEET) 

VEAB 

DRILLED 

REFEreNCE(S) 

NOTES 

T 

R 

SEC. 

BU4 

PUBLIOJTICW 

YEAR 

PAGE 

ux. 

HO. 

1". 

Enclno  Ranch 
(SeMinolc)   Hot 
Springs 

34*09.1'N 
n8-29.0'W 

Van  Nuys   (Tlj*) 

B5 

USGS  P.P.   492 

1965 

23 

112    A 

85 

USia  MSP   338 

1915 

246-247 

Loa 

Angeles 
8 

16 

RadluB  SuUur   Spring 

IS 

HW 

14 

SB 

Hollywxx)   (Til') 

80 

USGS   P.P.   492 

1965 

23 

11?  S 

(^663   Melros«  Ave.) 
near   Gower  St.) 

1000± 

CA.    1904 

USGS  WSP   338 

1915 

71-7? 

Angeles 
10 

Oil  test  well;    later 
bathing  resort 

n 

BlBlni   Hot   Springs 

IS 

13W 

19 

SB 

HollyiMod   (Tlj'l 

104 

USGS  P.P.   492 

1965 

23 

112  C 

(3rd  8.  Vermont  Ave.) 

104 

1750± 

CA.    1903 

USGS  WSP   338 

1915 

71 

Los 

Angeles 
11 

Oil   test  well;    later 
bathing  resort 

104 

USGS  WRI    33-13 

1974 

10 

7S 

KARIPOSA   SHEET 


1 

Paoha  Island 

1 
2N 

27E 

31 

« 

Mono  Craters 
(15') 

176 

USGS  P.P.   492 

1965 

23 

120 

176 

USGS  WSP   338 

1915 

144-145 

Mono   7 

176 

USGS  WRI    33-73 

1974 

6 

8 

Springs  and  steaa 

vents 

203 

CDOG  TR  13 

1975 

48 

55 

2 

Geothemal   Resources 
InterTiatlonal  "State 
P.R.C.   4397.1"   1 

IN 

27E 

17 

fC 

^tono  Craters 
(15'1 

130 

4110 

1971 

CDOG  Sum,   Op.   V.    57,   no.    2 

1971 

13 

Geotherval  Resources 
Intematiorial    "State 
P.R.C.   4397.1"   1 

129 

4110 

1971 

CDOG  TR   13 

1975 

48 

57 

Also  see  p.    35 

3 

Springs 

m 

2eE 

6 

m 

Cowtrack  Mtn. 
(15') 

? 

1950 

Shown   as   hot    spring 
on  Mt.  Morrison 
30'    quad. 

4 

Benton  Hot  Springs 

2S 

31E 

2 

M) 

Glass  Htn.    (15') 

135 

USGS   P.P.    492 

1965 

23 

127 

135 

US(^  WSP   338 

1915 

136 

Mono   12 

136 

USGS  WRI    33-73 

1974 

6 

10 

5 

Bertrand  Ranch 

IS 

32E 

8 

^G 

Benton    (15' J 

70 

USGS   P.P.   49? 

1965 

23 

127A 

Location  somewhat 
uncertain 

USGS  WSP   338 

1915 

322 

Itono   10 

6 

Reds  Meadows  Hot 
Springs 

37-37 
119-04 

I'N 
7'W 

Devils  Postplle 
(15') 

90-120 

USGS  P.P.   492 

1965 

23 

128 

120 

USGS  WSP   338 

1915 

55-56 

Madera  6 

7 

Two  fu»aroles 

T4S 

27E 

6 

H) 

Devils  Postplle 
(15') 

USGS  GO  437 

1965 

B 

puaarole 

T4S 

27E 

7-8 

H> 

Devils  Postplle 
(15') 

USGS  QQ  437 

9 

Fish  Creek  Hot 
Springs 

5S 

27E 

8 

K) 

Devils  Postpile 
(15') 

110 

USGS  P.P.   492 

1965 

23 

129 

37-32 

119-01 

N 

USGS  WSP   338 

1915 

56 

Fresno  2 

USGS  GO   437 

1965 

10 

Casa  Diablo 
Geotherial  Hell 

3S 

28E 

31 

fD 

Mt.  Morrison 
(15') 

128 

CDWR  Long  Valley  Invest. 

1967 

PI.    2, 

107 

Geothenaal  Hell 

CDWR  long  Valley  Invest. 

1967 

PI.   2, 
107 

Second  well  in 
SecUon   31 

11 

Ritchie  uelU 
1    thru   3 

3S 

28E 

32 

tt> 

Mt.   mrrlson 
(15'1 

CTOG  Map  G  5-1 

1973 

Bathrlcic  Uella  1  >  2 

CDOG  Hap  G  5-1 

1973 

- 

- 

See  Appendix  D  for  location. 


94 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


MARIPOSA   SHEET 


APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND   WELLS 


LOC. 
NO. 

NAHE 

LOCATICW 

QUADRANGLE 

vaTER 

TEMP. 

CD 

TOT  At 
DEPTH 
(FEET) 

YEAR 

DRILLED 

REFERENCE (S) 

, 

NOTES 

T 

R 

SEC. 

B&H 

PUBLICATION 

YEAR 

PAGE 

UX. 

NO. 

11 

Na^M  Power  Co.  i 
Assoc.  Hells 

3S 

28E 

32 

K) 

Mt.   Horrlson 

(15M 

Max. 
352 

Max. 

1000 

1959- 
196? 

CDOG  TR    13 

1975 

48 

60 

Also  see  p.    35 
(20  wells) 

1? 

C«s.  Diablo  Hot 
Springs 

"is 

2ec 

32 

W 

Mt.    rtorrlson 
(15') 

115-194 

uses  P.P.    492 

1965 

23 

123 

115-194 

USGS  HSP   336 

1915 

146-147 

nno  IS 

3S 

28E 

31 

w 

128 

uses  HRI   33-73 

1974 

6 

1 

3S 

28E 

31 

w 

128 

CDWR  Long  Valley  Invest. 

1967 

107 

Cass  Olablo  Hot 
Springs 

3S 

2eE 

32 

M) 

115-194 

CDOG  TR   13 

1975 

48 

58 

n 

Ritchie  Hells 
04,    5,    6 

3S 

28E 

32 

H) 

Mt.   Morrison 
(15'> 

CDOG  Map   G  5-1 

1973 

■ 

14 

htxio  County  Sheriffs 
Substation  Hell 

IS 

2eE 

33 

H) 

Mt.  Itorrlfion 
(15') 

79 

75 

1962 

CDHR  Mam.   Basin  Rept. 

1974 

39 

91 

<3)HR  Long  Valley  Invest. 

1967 

107 

15 

Hagma  Power  Co. 
Chance  #2 

3S 

28E 

35 

M) 

CDOG  Hap  G  5-1 

1973 

" 

~ 

Casa  Diablo  Hot  Pool 
Hell 

275 

80S 

1961 

CDMG  SR   75 

1963 

11 

12 

16 

Casa  Diablo  Hot  Pool 

3S 

2eE 

35 

W) 

Mt.    ttorrison 
(15'l 

180 

USGS   P.P.   492 

1965 

23 

124 

120-180 

USGS  HSP   338 

1915 

147 

nsno  16 

165 

USGS  HRI    33-73 

1974 

6 

« 

165 

CDHR  Long  Valley  Invest. 

1967 

110 

180 

CDOG  TR   13 

1975 

48 

59 

17 

Hot   spring 

3S 

2eE 

13 

w 

Mt.   Morrison 
(15') 

170 

USGS   P.P.    492 

1965 

23 

122 

- 

USGS  HSP   338 

1915 

147 

Mono  14 

180 

USGS  HRI    33-73 

1974 

6 

2 

174 

CDOG  TR   13 

1975 

46 

61 

18 

Hot   springs 

3S 

28E 

25 

H3 

Mt.   Morrison 
(15') 

120-203 

USGS  P.P.    385 

1964 

PI.    1 
80-81 
fig.    39 

5 

200 

CDHR  Long  Valley  Invest. 

1967 

109 

200 

USGS  HRI    33-73 

1974 

6 

3 

Hot  Creek  Geysers 
(Springs) 

194-203 

CDOG  TR   13 

1975 

48 

62 

19 

Harm  spring 

3S 

29E 

7 

H> 

Mt.   Morrison 
(15-  ) 

1007 

USGS   P.P.    385 

1964 

PI.    1 
80-81 
fig.    39 

10 

?0 

Whltjnore  Hani  Springs 

4S 

29E 

e 

hC 

Mt.   Marrlson 
(15') 

90 

USGS   P.P.    492 

1965 

23 

126 

100 

USGS  HSP   338 

1915 

147.148 

Mono   17 

Whltsnre  Hot  Springe 

91 

CDOG  TR   13 

1975 

48 

64 

21 

Harsi  spring 

3S 

29E 

31 

W 

Mt.   Morrison 
(15') 

140 

USGS  P.P.    385 

1964 

80-81 

8 

- 

USGS  HRI    33-73 

1974 

6 

7 

142 

CDWR  Long  Valley  Invest. 

1967 

112 

Hot  springs 

136 

CDOG  Tl>   13 

1975 

48 

63 

•    8*0  Appendix  D   for    loc«tlo 


1985 

MARIPOSA    SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  95 

APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


map" 

LOC. 
NO. 

NAME 

LOCATION 

gUADRANCLE 

HATER 
TEMP. 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 

, 

NCTES 

T 

R 

SEC. 

8&M 

PUBLICATI  :W 

YEAR 

PAGE 

LOC. 
NO. 

22 

Hot  spring 

3S 

29C 

29 

» 

m..  Hwrlson 
(15') 

172 

CDWR  »ta0.  Basin  Rept. 

1973 

40 

?3 

Hot   sprlTiq 

3S 

nt 

17 

Kl 

Mt.   Harrison 
(15M 

131 

CDWR    Mam.    Basin    Rept. 

1973 

40 

24 

"Tt»  Geysers* 

3S 

29E 

30 

IC 

uses   P.P.    492 

1965 

'' 

125 

n 

D^Y  Hot   Spring 

3S 

29E 

21 

W 

Ht.   Itorrlson 
(ISM 

126. 
134 

USGS  WRI    33-73 

1974 

6 

5  t   6 

Hot  springs 

128, 
132 

CDWR  Long  Valley  Invest. 

1967 

111 

27 

omTrec 

omrrer 

26 

Warw  ST>rln<3 

3T24.75'N 
119*08. 35'N 

Kaiser  Peak    (15-) 

95 

Written  contn. 
V.P.   Lockwood 

2S 

Itooo  Hot    Springs 

7S 

27E 

16 

K) 

Kaiser  Peak   CIS') 

112 

USGS  P.P.    492 

196S 

23 

130 

- 

USGS  WSP    338 

1915 

55 

Fresno  4 

30 

Keough  Hot   Springs 

8S 

33E 

17 

Ml 

Bishop   (15' ) 

130 

USGS   P.P.    492 

1965 

23 

138 

130 

USGS  >ISP   338 

1915 

148 

Inyo  1 

138, 

130 

USGS  Va   33-73 

1974 

6 

9  >  11 

Loc.   9   In  error; 
should  be  In  Range 
33 

31 

Blaney  Fieadows  Hot 
Sprljigs 

8S 

2aE 

23 

N) 

Blackcap  Htn 
(15') 

110 

USGS  P.P.    492 

1965 

23 

131 

lie 

USGS  WSP   338 

1915 

54-55 

Fresno  5 

32 

Grapevine  Spring 

lis 

42E 

3 

K) 

Ubehebe  Crater 
<15'  1 

USGS  WRI    33-73 

1974 

10 

93 

NEEDLES  SHEET 


1 

Fla«ingo  Well 

ION 

20E 

13 

SB 

Bannock    (15' ) 

104 

- 

- 

USGS  WRI    33-73 

1973 

8 

30 

2 

Ruricka 

IS 

24E 

9 

SB 

Parker   (15M 

90 

- 

" 

USGS  P.P.   4e6-G 

1973 

3 

Ruzlcka,   Oeahrlng 
and  Fortner 

IS 

24E 

10 

SB 

Parker   115') 

84 

290 

1959 

USGS  P.P.    486-G 

1973 

4 

Rio  Mesa  Ranch  #2 

IS 

24E 

10 

SB 

Parker  <15') 

86 

332 

- 

USGS  P.P.    48&-C 

1973 

Rio   rtesa  Ranch  «1 

86 

- 

- 

USQS   F.F.    486-G 

1973 

5 

V.    Ruzlcka 

IS 

24E 

16 

SB 

Parker    (IS') 

108 

225 

1959 

USGS   P.P.    486-G                                         1973 

REDDING  SHEET 


1 

Tuscan    (Lick)   Springs 

28H 

2W 

32 

W 

Tuscan  Springs 
(7i|') 

86 

USGS   P.P.    492 

1965 

21 

45B 

USGS  WSP    338 

1915 

2B9-291 

Tehaaa  5 

Saline  with  HjS 

2 

Stlnklr.q   Springs 

27N 

8W 

3 

W 

Colyear  Springs 
(15') 

101 

USGS  Water   Res.    Dlv.    Open  File 
Rept.    (No.   Coast   and   Klajnath 
Htns.) 

1968 

33 

SACRAMENTO  SHEE 


1 

Valley  Springs 

5N 

IDE 

24 

m 

Valley  Springs 
(IS') 

75 

USGS  P.P.    492 

1965 

23 

113A 

75 

USGS  WSP   338 

191S 

300-301 

Calaveras 

1 

Saline 

•  S«e  Appendix  D  for  locAtion. 


96 

SALTON  SEA  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND  WELLS 


• 
HAP 
LOC. 
NO. 

NAME 

UXIATION 

QUADRANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 

NOTES 

T 

R 

SEC. 

B6M 

PUBLICATION 

YEAR 

PAGE 

LOC. 
NO. 

1 

Kaiser  North  Well 

3S 

15E 

4 

SB 

Coxcomb  Mtn. 
(15') 

65 

Rex  unpub. 

1972 

4 

186 

? 

IhuriMr  Rsqsdale  Well 

4S 

15E 

17 

SB 

Coxcomb  Ntn. 
<15') 

104 

600 

Rex  unpub. 

1972 

1 

193 

3 

Desert  Center  Airport 
Well 

5S 

16E 

e 

SB 

CoxcoITi)  Mtn. 
(15') 

66 

225 

Rex  unpub. 

1972 

4 

99 

Possibly  in  55-16E- 
Sec.  B 

4 

Dos  PalBss  Spring 

8S 

HE 

3 

SB 

Orocopia  (Tlj') 

60 

U5G5  P.P.  492 

1965 

24 

176 

- 

uses  W5P  336 

1915 

315 

Riverside 

IB 

84 

- 

CDWR  Bull.  143-7 

1970 

PI.  2 

5 

Sunland  Oil  Well 

5S 

15E 

29 

SB 

Chuckwalla  MtJls. 
(15'1 

66 

650 

Rex  unpub . 

1972 

4 

177 

6 

Dlv.  of  Highways, 
Desert  Center  Well 

55 

15E 

27 

SB 

Chuckwalla  Mtns. 
(15') 

89 

585 

Rex  unpub. 

1972 

3 

187 

7 

Stanley  Raqsdale  Well 

5S 

15E 

27 

SB 

Chuckwalla  Mtns. 
(15') 

91 

600 

Rex  unpub. 

1972 

3 

176 

8 

Trailer  Park  East  and 
West  Wells 

5S 

15E 

23 

SB 

Chuckwalla  Mtns. 
(15') 

93,  94 

500 

Rex  unpub. 

1972 

3 

192,  194 

9 

LaTy  C  Trailer  Park 
Well 

5S 

15E 

13 

SB 

Chuckwalla  Mtns. 
I15'> 

86 

Rex  urpub. 

1972 

4 

198 

10 

Howard  Brown  Well 

5S 

16E 

7 

5B 

Chuckwalla  Mtns. 
(15') 

95 

650 

Rex  unpub. 

197? 

? 

185 

n 

Wiley  well  Rest  »re« 

6S 

20E 

33 

SB 

McCoy  Spring 
(15') 

lie 

17O0 

Rex  unpub. 

1972 

1 

197 

1? 

Mesa  Verde  Well 

65 

21E 

36 

SB 

Ripley  (71i'l 

88 

360 

Rex  unpub. 

1972 

3 

191 

n 

Nicholls  Warm  Springs 

6S 

21E 

36 

SB 

Ripley  (Tij') 

91 

638 

1946 

U5GS  P.P.  486-G 

1973 

111 

14 

Riverside  Co.  Airport 
Well 

65 

?2E 

32 

SB 

Ripley  (7H' ) 

68 

Rex  unpub. 

1972 

3 

183 

15 

Ballard's  Tnjdchaven 
Well 

105 

lOE 

IB 

SB 

Truckhaven  (7)j') 

104 

CDWR  Bull.  143-7 

1970 

36 

5 

104 

uses  WRI  33-73 

1974 

8 

29 

le 

Truckhaven  Well 

105 

lOE 

16 

SB 

Truckhaven  (7)j') 

104 

1200 

Rex  unpub. 

1972 

2 

74A 

17 

Truckhaven  Well 

lOS 

lOE 

16 

5B 

Truckhaven  (71(') 

90 

1200 

Rex  unpub. 

1972 

3 

74 

le 

"Hunter's  Spring"  New 
Well 

es 

HE 

12 

SB 

Durmid  (7)(') 

90 

CDWR  Bull.  143-7 

1970 

36 

24 

19 

King,  Spa  Well 

es 

12E 

36 

SB 

Frlnk  NW  (TJj'  ) 

174 

347 

Rex  unpub. 

1972 

1 

127 

?0 

New  Pilger  Hot 
Mineral  Well 

85 

12E 

36 

SB 

Frlnk  NW  (71,') 

160 

CDWR  Bull.  143-7 

1970 

36 

23 

Pilger  Estates  Well 

160 

uses  WRI  33-73 

1974 

8 

25 

21 

Hot  mineral  well 

9S 

12E 

2 

SB 

Frink  NW  (Tij') 

166 

300 

USGS  P.P.  492 

1965 

24 

176A 

Hot  mineral  Spa  well 

190 

U5G5  Water  Res.  Div.  Open  File 
(Colo.  Desert) 

1969 

9 

22 

Bruhfords  Well 

9S 

12E 

2 

SB 

Frlnk  NW  (7I5'  ) 

143 

247 

Rex  unpub. 

1972 

1 

126 

170-174 

325 

USGS  WRI  33-73 

1974 

e 

27 

23 

Youth  Spa  Well 

95 

12E 

2 

SB 

Frlnk  W  (71,'  ) 

136 

611 

Rex  unpub. 

1972 

1 

12 

24 

Unnamed  well 

95 

12E 

2 

5B 

Frlnk  riw  (71)'l 

159-174 

CDWR  Bull.  143-7 

1970 

92 

7S 

Fountain  youth  Hot 
Hineral  Well 

95 

13E 

7 

SB 

Frlnk  NW  (7)5') 

140 

CDWR  Bull.  143-7 

1970 

36 

21 

26 

frlnk  Springs 

95 

13E 

20 

SB 

Frlnk  NW  (7),'  ) 

75 

CDWR  Bull.  141- 

1970 

36 

20 

•   S««  Appendix  D   for    location. 


1985 

SALTON    SEA    SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  97 

APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND  WELLS 


MAP 
LOC. 
SO. 

NAME 

LOCATICW 

QUADRANGLE 

WATER 
TEMP. 

TOTAL 
DEPTH 
(FEET) 

YEAR 

DRILLED 

REFERENCE (S) 

NOTES 

T 

R 

SEC. 

B&H 

PUBLICATION 

YEAR 

PAGE 

LOC. 
NO. 

27 

Hjdle,    Gravel  Co.  Well 

9S 

13E 

21 

SB 

Frlnk   NW   (T^i"  ) 

se 

Rex  unpub. 

1972 

3 

125 

26 

Mid  volcsno(sl 

9S 

HE 

35 

SB 

Wlster    (A'l 

Mln.   survey 

So.    Pac.    Kin.   Sur. 
unpub.   maps   1961 

29 

Mjd   volc«no(st 

9S 

13E 

36 

SB 

Wister   (7>,'l 

Min.   survey 

So.    Pac.    Min.   Sur. 
unpub.   maps   1961 

30 

Hjd   volcano(s) 

lOS 

13E 

2 

SB 

Wlster    (7>-  ) 

Min.    survey 

So.    Pac.    Kin.    Sur. 
unpub.  maps  1961 

31 

Hid  volcanoes] 

lOS 

13E 

1 

SB 

Wlster    171,') 

Min.   survey 

So.    Pac.    Kin.    Sur. 
unpub.   maps   1961 

32 

Hjd   volcano(s) 

lOS 

13E 

10 

SB 

Wlster   (71,') 

Min.    survey 

So.    Pac.    Hln.   Sur. 
unpub.   maps   1961 

33 

Hjd   volcano(s) 

lOS 

13E 

U 

SB 

Wlster   (Tlj') 

mn.  survey 

So.  Pac.  mn.  Sur. 
unpub.  naps  1961 

34 

Hjd  volcano(s) 

lOS 

13E 

23 

SB 

Wlster   ITH') 

Min.   survey 

So.  Pac.   mn.   Sur. 
unpub.   maps    1961 

35 

»*id  volcano! s) 

lOS 

13E 

24 

SB 

Wlster   (7H'  ) 

Hln.   survey 

So.    Pac.    Mln.   Sur. 
unpub.   maps   1961 

36 

Magma  Energy  Inc. 
Dearborn   1 

12S 

13E 

30 

SB 

Calipatria   (7H* ) 

4135 

1972 

Map 

16 

S.L.  Werner,   written 
comm.    10/25/73. 

37 

omrrEr 

36 

Western   GeotherTMl 
Sinclair  4 

12S 

13E 

4 

SB 

Nlland   (75)') 

•212 

5306 

1964 

CDWR  Bull.    143-7 

1970 

45,    87 

Also  see  PI.   2 

328 

4503 

USGS  Open  File 
(Imperial  Valley) 

1976 

20 

70 

39 

Western  Geothemtal 
Sinclair  3 

12S 

13E 

10 

SB 

NUand   (7)iM 

- 

6922 

1962 

CDWR  Bull.    143-7 

1970 

45 

334 

4720 

USGS  WRl    33-73 

1974 

8 

50 

228 

5327 

USGS  Open  File 
(Imperial   Valley) 

1976 

20 

72 

40 

Earth  Dierqy  Inc., 
Elnore  1 

lis 

13E 

27 

SB 

Nlland   (7Ji'  ) 

536 

7117 

- 

USGS  WRI    33-73 

1974 

8 

55 

7117 

1964 

CDWR  Bull.    143-7 

1970 

45 

41 

Imperial  TTiemal 
Prod.   I.I.D.   1 

lis 

13E 

23 

SB 

Nlland    (TSi'l 

430 

5232 

1962 

CnVR  Bull.    143-7 

1970 

45,    87 

450 

4859 

USGS  WRI    33-73 

1974 

8 

54 

334 

5232 

USGS  Open  File 
(Imperial  Valley) 

1976 

18 

39 

42 

laperial  Therwal 
Prod.   I.I.D.    3 

lis 

13E 

23 

SB 

Nlland   (71j') 

221 

1695 

1965 

CDWR  Bull.    143-7 

1970 

45,    87 

43 

Ii^jerial  Thermal 
Prod.   I.I.D.    2 

lis 

13E 

22 

SB 

Nlland   (7^') 

626 

5826 

1963 

CDWR  Bull.    143-7 

1970 

45.    87 

Temp,  from  nxffler 
and  White  (1969) 

44 

45 

660 

56O0 

USGS  Open  File 
(Imperial   Valley) 

1976 

18 

37 

Mud  Pots 

lis 

13E 

14 

SB 

Nlland   (Tlj-  ) 

100 

to 

boiling 

USGS   P.P.    492 

1965 

25 

182A 

Kid  Pot 

lis 

13E 

14 

SB 

Nlland    (71j*) 

100 

to 

boiling 

USGS   P.P.   492 

1965 

25 

182A 

46 

47 

Halsson'B   Spa 

us 

13E 

13 

SB 

Nlland  <7l(M 

106 

Rex  unpub. 

1972 

1 

96 

Halsson's  well 

US 

13E 

13 

SB 

Nlland    (THM 

104 

CDWR  Bull.    143-7 

1970 

36 

19 

48 

Earth   Energy    Inc. 
Hudson   Ranch   1 

US 

13E 

13 

SB 

Nlland    (Tl,-) 

192 

6141 
500 

1964 

CDWR   Bull.    143-7 
USGS    WPI    3^-7? 

1970 
1974 

45 
8 

53 

49 

Joseph  O'Neill. 
Sportsman    1 

US 

13E 

23 

SB 

Nlland    (7>i') 

590 

4729 

1961 

CDWR   Bull.    143-7 

197C 

45 

Temp,    from  Kjffler 
and  White   (1969) 

392 

4729 

1961 

Map 

5 

S.L.  Werner  written 
co™.   10/25/73 

495 

3000 

USGS  Open  File 
(Imperial  Valley) 

1976 

18 

40 

See  Appendix  D  for   location. 


98 

SALTON  SE*  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND   WELLS 


LOC. 
HO. 

NME 

LOCATION 

QUADRANGLE 

lATER 
TEKP. 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 

, 

NOTES 

T 

R 

SEC. 

BU4 

PUBLICATION 

YEAR 

PACE 

LOC. 

NO. 

50 

E«rth  Energy  Inc. 
River  Ranch  1 

lis 

UE 

23 

SB 

Nilsnd  (7S'  ) 

653 

8100 

1963 

CDWR  Bull.  143-7 

1970 

45 

■  ■ 

Tea^.  from  Muffler 
and  White  (1969) 

51 

Hid  Pot 

lis 

UE 

24 

SB 

Niland  (7»i'  ) 

100 

to 

boiling 

USGS  P.P.  49? 

1965 

25 

182A 

(Hid  volcanoes) 

100 

USGS  Water  Rea.  Div.  Open  Pile 
(Colo,  Desert) 

1969 

10 

100 

- 

CDWR  Bull.  143-7 

1970 

94 

52 

Hell 

US 

14E 

15 

SB 

Weatjnorland  (T^'l 

282 

6350 

USGS  WRl  33-73 

1974 

8 

52 

53 

c.  Bowles  Hell 

lis 

14E 

14 

SB 

Iris  (71,M 

106 

920 

Rex  unpub. 

1972 

1 

101 

54 

Cai^)  Dunlop  Well 

lis 

14C 

1 

SB 

Iris  (A'l 

112 

825 

Bex  unpub. 

1972 

1 

1 

55 

J.  Ullliiu.  Well 

ns 

15E 

5 

SB 

Wiest  (TS'l 

102 

666 

Rex  unpub. 

1972 

2 

59 

98 

864 

CDOG  TR  15 

1974 

Table  la 

7 

56 

West  Store  Well 

ns 

15E 

5 

SB 

Wiest  <71j'  ) 

102 

812 

Bex  unpub. 

1972 

? 

60 

100 

797 

CDOG  TR  15 

1974 

Table  la 

8 

57 

Butters-Rivers  Well 

us 

15E 

3 

SB 

Wiest  (71,') 

104 

S80 

Rex  unpub. 

1972 

1 

lib 

58 

Hjlberry  School  Well 

us 

15E 

3 

SB 

Wiest  (Tij-  ) 

106 

890 

Bex  unpub. 

1972 

1 

50 

105 

890 

CDOG  TR  15 

1974 

Table  la 

6 

59 

M.  Lunceford  Well 

us 

15E 

16 

SB 

Wiest  (7H-) 

106 

780 

Rex  unpub. 

1972 

1 

49 

104 

764 

CDOG  TR  15 

1974 

Table  la 

9 

60 

■meodore  Shank  Well 

13S 

15E 

?? 

SB 

wiest  (735' ) 

112 

1000 

Rex  unpub. 

1972 

1 

44 

61 

J.  RatUff  Well 

13S 

15E 

23 

SB 

Wiest  (71iM 

133 

1300 

Rex  unpub. 

1972 

1 

6 

130 

1307 

CDOG  TR  15 

1974 

Table  la 

10 

6J 

Butters-Reese  well 

US 

15E 

24 

SB 

Wiest  n>f) 

112 

700 

Rex  unpub. 

1972 

1 

5 

109 

704 

CDOG  TR  15 

1974 

Table  la 

11 

63 

Dlckenaan-Butters 

US 

15E 

U 

SB 

Atos  (71iM 

126 

Rex  unpub. 

1972 

1 

19 

64 

Heyer-Dlckennan 

US 

15E 

12 

SB 

Ajnos  n^'  ) 

98 

Rex  unpub. 

197? 

2 

114 

65 

Schoenan-Koluyek  Well 

us 

16E 

6 

SB 

AJTOS  (7I5'  ) 

92 

616 

Rex  unpub. 

1972 

3 

53 

F.  Schonemsn  Well 

92 

619 

CDOG  TR  15 

1974 

Table  la 

15 

66 

Ton  Olesh  well 

us 

16E 

6 

SB 

Amos  (7H' ) 

90 

300 

CDOG  TR  15 

1974 

Table  la 

16 

100 

300 

Rex  unpub. 

1972 

2 

5? 

67 

omTTED 

60 

Tsylor  Wei! 

us 

15E 

1 

SB 

Ancs  (7!,M 

U6 

1089 

Rex  unpub. 

1972 

1 

54 

132 

1089 

CDOG  TR  15 

1974 

Table  la 

5 

69 

P.  Rebrlk  Well 

i;s 

16E 

11 

SO 

Anos  (7T,*) 

107 

925 

Bex  unpub. 

lo?? 

1 

55 

102 

931 

CDOG  TR  15 

1974 

Table  la 

4 

•  S««  Appandlx  L   Cur    location. 


1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  99 

SALTON   SEA   SHEET  APPENDIX    B   -    TABULATED    LIST   OF    THERMAL    SPRINGS   AND  WELLS 


UX. 

NO. 

fJAMK 

LlXTATICN 

gUM)  RANCLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REreRENCE  (b) 

, 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATIOW 

YEAR 

PAGE 

LOC. 
NO. 

70 

Richard  Cowll  Mil 

12S 

ISE 

3S 

SB 

AIDS   (7I|'I 

92 

344 

Rex  unpub. 

1972 

3 

56 

91 

346 

axx  TK  15 

1974 

Table   la 

3 

71 

G.  Bro*^ell  well 

ws 

15E 

27 

SB 

Wlest    (TljM 

94 

4  30 

Rex  unpub. 

1972 

^ 

56 

92 

429 

COOG  TR   15 

1974 

Table  la 

2 

7? 

D.   BroM^ell   u«ll 

12S 

15E 

23 

SB 

Wleat  (TH-) 

88 

325 

Rex  unpub. 

19-'? 

^ 

57 

90 

330 

CDOG  TR   15 

1974 

Table   la 

1 

73 

L.C.   winters 

5S 

??E 

33 

SB 

McCoy  Wash   (7lj'l 

88 

380 

1962 

USGS  P.P.    466-0 

1973 

111 

74 

C.   Cheely 

5S 

22t 

35 

SB 

McCoy  Wash   (7H' ) 

88 

450 

1965 

USGS   P.P.   486-G 

1973 

111 

75 

E.   Fortj^cr 

5S 

?2E 

35 

SB 

McCoy   Wash    {7^}') 

88 

405 

1964 

USGS   P.P.   486-G 

1973 

111 

76 

USGS  Well 

es 

J2E 

9 

SB 

McCoy  Wash   (75j') 

90 

276 

1967 

USGS   P.P.    466-G 

1973 

112 

77 

Z.  weeks 

6S 

2JE 

15 

SB 

McCoy  wash  (Tlj') 

91 

585 

1963 

USGS   P.P.   486-0 

1973 

112 

76 

L'S^^S    "ell 

&S 

22E 

20 

SB 

»tCoy  Wash    (7>,M 

88 

276 

1967 

USGS   P.P.   486-G 

1973 

112 

79 

Besha  «1 

6S 

22E 

28 

SB 

McCoy  wash  (7I5') 

88 

- 

1965 

USGS  P.P.   466-0 

1973 

112 

eo 

Bill  Passey 

6S 

?2E 

32 

SB 

RitJley  ITSi'l 

88 

560 

1947 

USGS   P.P.   486-G 

1973 

113 

81 

Bash.  «3 

7S 

21E 

14 

SB 

Ripley    (Tl)') 

113 

1368 

1966 

USGS  P.P.    466-G 

1973 

113 

82 

Southern  Pacific  Co, 

lis 

21E 

5 

SB 

Quartz  Peak   (15* ) 

88 

752 

- 

USGS   P.P.    486-G 

1973 

114 

83 

tVC   Nagmanax  #3 

lis 

13E 

33 

SB 

Nlland   (TH* ) 

568 

3083 

1972 

USGS  Open  File 
(Imperial  Valley) 

1976 

18 

46 

PPC   Magmaiwut   K2 

lis 

13E 

33 

SB 

Obsidian  Butte 
(7>,M 

533 

4360 

1972 

USGS  Open   File 
(Inperial  Valley) 

1976 

16 

48 

84 

WC   Maflma»ax   «1 

lis 

13E 

33 

SB 

Niland   (Tlj*  ) 

509 

2263 

1972 

USGS  Open  File 
(Imperial  Valley) 

1976 

18 

49 

wc  woolsey  wl 

236 

2340 

1972 

USGS  Open  File 
(Imperial  Valley) 

1976 

18 

50 

SAN   BERNARDINO   SHEET 


1 

Ne*iberry  Spring 

9N 

3E 

32 

SB 

Ne«berry  (15') 

77 

USGS   P.P.   492 

1965 

24 

157 

77 

USGS  WSP    338 

1915 

317 

San 
Bern.   20 

2 

Spring  in  Deep  Creek 
Canyon 

3N 

3W 

15 

SB 

Lake  Arrowhead 
(15') 

80-100 

USGS  P.P.    492 

1965 

24 

159 

3 

Spring  in  Deep  Creek 
Canyon 

3N 

3W 

14 

SB 

Lake  Arrowhead 
(15') 

80-100 

USGS   P.P.   492 

1965 

24 

160 

4 

Tylers  Bath  Spring 

2N 

6W 

26 

SB 

San  Bernardino 
(15') 

92 

USGS  P.P.   492 

1965 

24 

158 

90 

USGS  WSP   338 

1915 

35 

San 
Bern.   34 

USGS  WSP   142 

1905 

Plate 
XII 

Location  of  Hot 

Spring  in  Lytle 
Canyon 

5 

water»ar.  Hot   Springs 

IN 

4H 

11 

SB 

San  Bernardino 
(15') 

l.-'l 

USGS  P.P.    492 

1965 

24 

162 

- 

USGS  WSP    338 

1915 

33 

San 
Bern.   35 

210 

USGS  WU    33-73 

1974 

10 

66 



•  S«e   Appendix  D   for    location. 


100 

SAN  BERNARDINO  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


• 
NAP 

UX. 

KO. 

NAME 

LOCATION 

QUADRANGLE 

WVTER 
TENP. 
CD 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILIED 

REFERENCE (S) 

, 

NOTES 

T 

R 

SEC. 

BtM 

POBLI CATION 

YEAR 

PAGE 

LOC. 

NO. 

e 

Arrowhead  Hot  Springs 

IN 

4W 

11 

SB 

San  Bernardino 
US') 

110-181 

USGS  P.P.  492 

1965 

24 

162 

202 

USGS  WSP  338 

1915 

32-33 

Sen 
Bern.  36 

154 

USGS  WRl  33-73 

1974 

10 

65 

7 

Urblta  Hot  Springs 

IS 

4W 

16 

SB 

San  Bernardino 
(15') 

80-106 

USGS  P.P.  49? 

1965 

24 

162A 

106 

USGS  WSP  338 

1915 

36-37 

San 
Bern.  38 

s 

Veil 

IS 

4W 

16 

SB 

Son  Bernardino 
(15') 

106 

175 

USGS  WRI  33-73 

1974 

10 

70 

9 

Well 

IS 

4W 

16 

SB 

San  Bernardino 
(15') 

107 

600 

USGS  WRl  33-73 

1974 

10 

71 

10 

Well 

IS 

4W 

?? 

SB 

San  Bernardino 
(15') 

112 

642 

USGS  WRI  33-73 

1974 

10 

72 

11 

well 

IS 

4W 

22 

SB 

San  Bernardino 
(15M 

124 

852 

USGS  WRI  33-73 

1974 

10 

73 

17 

Wel 

IS 

4W 

22 

SB 

San  Bernardino 
(15') 

110 

975 

USGS  WRl  33-73 

1974 

1(1 

74 

13 

Harlem  Hot  Springs 

IN 

3W 

31 

SB 

Redlands  (?>,■) 

120 

USGS  P.P.  492 

1965 

24 

161 

- 

USGS  WSP  338 

1915 

35 

San 
Bern.  37 

14 

Well 

IS 

3W 

6 

SB 

Redlands  (T!)') 

110 

138 

USGS  WRI  33-7' 

1974 

10 

69 

15 

Well 

IN 

3W 

32 

SB 

Redlands  tA'l 

130 

194 

USGS  WRI  33-71 

1974 

10 

67 

16 

Well 

IN 

3W 

33 

SB 

Redlands  (TJi'l 

124 

500 

USGS  WRI  33-73 

1974 

10 

66 

n 

Hot  Springs  in 
Santa  Ana  Canyon 

IN 

?W 

34 

SB 

Yucaipa  (7^') 

90 

USGS  P.P.  492 

1965 

24 

163 

17A 

Warm  spring  at  Baldwin 
Ijike 

?N 

IE 

12 

SB 

Lucerne  Valley 
(IS'l 

88 

USGS  P.P.  492 

1965 

24 

164 

B8 

USGS  WSP  338 

1915 

35 

San 
Bern.  33 

Pan  Hot  Springs 

2N 

le 

12 

SB 

USGS  Topo  nap 

1949 

18 

Well 

IN 

5E 

12 

SB 

Joshua  Tree  {15') 

lOB 

477 

USGS  WRI  33-73 

1974 

10 

95 

19 

Well 

IN 

8E 

2 

SB 

Twenty  Nine  Palms 
(15M 

128 

- 

USGS  WRI  33-73 

1974 

6 

17 

?0 

Well 

IN 

9E 

14 

SB 

Twenty  Nine  Palms 
(15') 

146 

- 

USGS  WRI  33-73 

1974 

6 

IB 

Jl 

Wel] 

IN 

9E 

29 

SB 

Twenty  Nine  Palms 
(15') 

118 

- 

USGS  WRI  33-73 

1974 

6 

19 

SAN  DIE(;0  SHEET 


1 

Well 

16S 

7W 

16 

SB 

Ij.  Mesa  (71j') 

80 

CDWR  Bull.  106-.' 

1967 

222 

2 

Well 

15S 

IW 

14 

SB 

El  Caloi.  (7S') 

87 

CDWR  Bull.  106-2 

1967 

208 

3 

Agua  Caliente  Springs 

14S 

7E 

lfl-19 

SB 

Agua  Caliente 
Springs  (71(') 

90 

USGS  P.P.  492 

1965 

24 

180 

- 

USGS  WSP  338 

1915 

46 

San 
Diego  9 

14S 

7E 

18 

SB 

101 

USGS  WRI  33-73 

1974 

10 

64 

14S 

7E 

18 

sa 

99 

Rex  unpub. 

1972 

2 

106 

14S 

IE 

18 

S3 

99 

USGS  Water  Res.  Dlv.  Open  File 
ftept.  (So.  Coast,  Transv.  & 
Pwiln,  Hangesl 

1968 

A-13 

•  See  Appendix  D  for  location. 


1985 

SAN   DIEGO    SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


101 


APPENDIX   B   -    TABULATED   LIST    OF    THERMAL   SPRINGS   AND  WELLS 


MAT 
LOC. 

NO. 

N?iMK 

LCX^TIC« 

QUADRANGLE 

WATER 
TEMP. 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REreRENCE  (S) 
(see    list  of   references    for   abb 

ruviationu) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATION 

YEAR 

PAGE 

UX. 
NO. 

4 

Hell 

les 

?w 

26 

SB 

Imperial  Beach 
(7>,M 

80 

CDWR  Bull.    106-r 

1967 

228 

5 

»«11 

18S 

TV 

28 

SB 

Imperial   Beach 

97 

CDWR   Bull.    106-? 

1967 

220 

6 

well 

185 

2« 

21 

SB 

Imperial  Beach 
(Tl,') 

82 

CDWR  Bull.    106-? 

1967 

227 

7 

»»n 

IBS 

IW 

31 

SB 

Imperial  Beach 

91 

CDWR   Bull.    106-? 

1967 

229 

e 

wu 

19S 

IW 

3 

SB 

otay  Mesa   (7ij'  ) 

83 

CDWR  Bull.    106-.^ 

1967 

231 

9 

W«ll 

les 

IW 

34 

SB 

Otay  Mesa    (71j') 

83 

CEWR  Bull.    106-? 

1967 

229 

10 

Kell 

IBS 

2W 

14 

SB 

Otay  Mtn.    ITH') 

60 

CDWR  Bull.    106-2 

1967 

233 

11 

Hell 

17S 

5E 

3 

SB 

CaiMron  Comers 

86 

CDWR  Bull.    106-2 

1967 

234 

12 

Herri'  Lazazc  well 

les 

7E 

8 

SB 

Tierra  Del  Sol 

101 

200 

Rex  ujipub. 

1972 

2 

87 

13 

JacuBt>a  Springs 

18S 

8E 

7  S  8 

SB 

Jacumba   (15') 

94,    96 

USGS  P.P.   492 

1965 

25 

181 

96 

USGS  WSP   338 

1915 

45 

San 
Diego  19 

101 

USGS  WRI   33-73 

1973 

8 

32-3 

14 

Raynond   Rasco  Well 

18S 

BE 

9 

SB 

Jacumba  (15') 

87 

160 

Rex  unpub. 

1972 

4 

141 

15 

Millers   Service 
Station  Well 

les 

9E 

35 

SB 

In-ko-pa  Gorge 
(7!,M 

93 

535 

Rex  unpub. 

1972 

3 

76 

16 

H.D.  Currey  Well 

16S 

9E 

35 

SB 

In-leo-pa  Gorae 

85 

350 

Rex   unpub . 

1972 

4 

159 

SAN 

FRANCISCO   SHEET 

HAP 

VX. 
NO. 

NAME 

LOCATICN 

QUADRANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET> 

YEAR 
DRILLED 

REFERENCE (S) 
{see   list  of   references   for   abfc 

reviations 

) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATION 

YEAR 

PAGE 

WC, 

NO. 

1 

Rocky  Point   Spring 

37-53. 5'N 
122-37.65W 

Bolinas   (7%') 

100 

USGS    P.P.    492 

1965 

22 

84 

- 

USGS  WSP    338 

1915 

80-81 

Marin   3 

Located  on   the 
beach  at  low  tide 

90 

USGS  Water   Res.    Dlv.   Open  File 
Rept.    (Ko.   Coast  &   Klamath 
Mtns.) 

1968 

23 

2 

Sulfur  Springs 

37*55.4'N 

Walnut  Creek 
(TJjM 

75-81 

USGS  P.P.   492 

1965 

22 

85 

1??-^ 

7.9'V 

USGS  WSP   338 

1915 

270 

Contra 
Costa    3 

SAN 

JOSE    SHEET 

1 

Byron  Hot  Springs 

IS 

3E 

15 

W 

Byron  Hot  Springs 
(7>i') 

72-120 

USGS  P.P.    492 

1965 

22 

86 

73-122 

USGS  WSP   338 

1915 

109-112 

Contra 
Costa  7 

83-96 

USGS  Water  Res.   Dlv.  Open  File 
{So.  Coast,   Transv.  &   Renin. 
Ranges) 

1968 

A-4 

2 

Warn  Springs 

5S 

IE 

18 

K) 

Livemore   (15*  ) 

85-90 

USGS  P.P.    492 

1965 

22 

87 

66-90 

USGS  WSP    338 

1915 

80 

Alaneda 

3 

(Alaavda  War*  Springs 
msslcff^   San  Jos*  Hot 
Springs) 

80 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,    Transv.   a    Penln. 
Ranges ) 

1968 

A- 3 

3 

Alum  Roc)c    fark 
Springs 

6S 

2E 

19 

H) 

Calaveras  Res. 
(7!,M 

62-87 

USGS  P.P.    492 

1965 

22 

88 

69-87 

USGS  WSP    338 

• 

1915 

208-217 

Santa 
Clara  3 

white   Sulphur    Spring 

84 

USGS  Water  Res.   Div.  open  File 
(So.    Coast.    Transv.    &    Penln. 
Ranges) 

1968 

A-17 

«  See  Appendix  D  for  location. 


102 

SAN  JOSE  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


• 
NAP 
UX. 
NO. 

NAME 

LOCATION 

eUADRAHGIf 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 

DRILLED 

BZFEREHCE(S) 

, 

NOTES 

T 

R 

SEC. 

BW 

PUBLICATION 

YEAR 

PACE 

UX. 
NO. 

4 

Gllroy  Hot  Springs 

9S 

4t 

36 

H) 

Gllroy  Hot 
Springs  (15') 

110 

USGS  P.P.  492 

1965 

22 

B9 

110 

USGS  WSP  338 

1915 

79-80 

Santa 
Clara  9 

1 

106 

USGS  W«ter  Res.  Dlv.  Oper  File 
(So.  Coast,  Transv.  &  Penin. 
Kanqes) 

1968 

A-ie 

SAN  LUIS  OBISPO  SHEET 


1 

Paso  de  Robles  Kid 
Bath  Springs 

26S 

12E 

20-;i 

ft- 

Fnso  Robles  (IS-) 

55-118 

USGS  P.P.  492 

1965 

22 

95 

122 

USGS  WSP  338 

1915 

73-75 

San  Luis 
Obispo  1 

(H.B.  Jenne) 

2&S 

12E 

20 

ff) 

108, 
110 

* 

" 

USGS  Water  Res.  Dlv,  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A-14 

Roman  type  pool 
in  baths 

2 

Paso  de  Robles  Hot 
Springs 

?6S 

12E 

33 

rc 

105 

c.  19O0 

USGS  P.P.  492 

1965 

2? 

96 

Vague  locations; 
wells  &  springs 

105 

640 

USGS  WSP  338 

1915 

72-73 

San  Luis 
Obispo  2 

(Paso  Robles  city 
Baths) 

101 

400 

US(;S  Water  Res.  Dlv.  Open  File 
(So.  Coast,  Transv.  &   Penin. 
Ranges) 

1968 

A-14 

1 

Santa  Ysabel  Springs 

27S 

12E 

14 

M) 

Paso  Robles  (15') 

94 

USGS  P.P.  492 

1965 

22 

97 

96 

USGS  WSP  338 

1915 

76-77 

San  LuLs 
Obispo  3 

(Sulphur  springs) 

92 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv,  &  Penin. 
Ranges) 

1968 

A-15 

4 

Wans  Well 

26S 

12E 

26 

m 

Paso  Robles  (15') 

Pers.  comn.  J.B. 
Koenlg,  1972 

5 

Pecho  Warm  Springs 

SOS 

IDE 

36 

t€t 

Horro  Bay  South 
(TljM 

72,  95 

USGS  P,P.  492 

1965 

22 

99 

Pecho  Warm  Springs 

30S 

lOE 

36 

H) 

Horro  Bay  South 

95 

USGS  WSP  338 

1915 

69-70 

San  Luis 
Obispo  7 

6 

Caffleta  Warm  Spring 

29S 

17E 

? 

H) 

La  Panza  (15') 

74 

USGS  P.P.  492 

1965 

22 

98 

Very  vague  location 

74 

USGS  WSP  338 

1915 

77-78 

San  Luis 
Obispo  5 

7 

San  LaiIs  (Sycamore) 
Hot  Spring 

31S 

12E 

32 

H) 

Arroyo  Grande 
(15') 

107 

USGS  P.P.  492 

1965 

22 

98A 

107 

937 

1886 

USGS  WSP  338 

1915 

70-71 

San  Luis 
Obispo  8 

Well  drilled  for  oil 

Sycamore  Hot  Springs 

100 

USGS  Water  Res.  Dlv,  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A-15 

e 

Hidden  Valley  Hot 
Springs 

31S 

12E 

32 

H) 

Arroyo  Grande 
(15') 

135 

40-50 

1908 

USGS  Water  Res.  Dlv.  Open  File 
(So.  Coast,  Transv.  S  Penin. 
Ranges) 

1968 

A-15 

9 

Newsom's  Springs 

3?S 

UE 

23 

m 

Arroyo  Grande 
(15') 

98 

USGS  P.P.  492 

1965 

22 

100 

(Arroyo  (Srande) 

100 

USGS  WSP  338 

1915 

ee-69 

San  Luis 
Obispo  9 

99 

USGS  Water  Res.  Dlv.  Open  File 
(So.  Coast,  Transv.  ft  Penin. 
Ranges) 

1968 

A-15 

SANTA  ANA  SHEET 


1 

Alvarado  Hot  Springs 
Well 

2S 

low 

24 

SB 

La  Habra  (7S' ) 

112 

5000± 

1910 

USGS  Water  Res.  Dlv,  Open  File 
(So.  Coast,  Transv.  ft  Penin, 
Ranges) 

1968 

A-7 

2 

I,a  Vlda  Mineral 

Sprlnio  Wrll 

3S 

9W 

2 

SB 

Yorba  Linda  (7))') 

110 

USGS  Water  Res,  Dlv.  open  File 
(So.  Coast,  Transv.  ft  Penin. 
Ranges) 

1968 

A-9 

Well  at  or  near 
former  springs 

3 

Wrl 

3S 

7W 

11 

SB 

Corona  North 
(7S'  ) 

119 

917 

USGS  WRI  33-71 

1974 

10 

89 

Drilled  In  1925  or 
earlier 

4 

Glen  Ivy  (Temescal) 
Hot  Spring 

5E 

6W 

10 

SB 

[v»ke  Mathews 
(T^j*  ) 

102 

US(;S  P.P.  49? 

1965 

^.1 

ll.T 

•  &••  Appandix  0  for  location. 


1985 

SANTA   ANA   SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 

APPENDIX  B  -  TABULATED  LIST  OF  THERMAL 


103 

SPRINGS   AND   WELLS 


• 
MM' 

LOC, 

HO. 

NAME 

lcx:ation 

OUADBANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 

, 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATIOW 

YEAR 

PAGE 

LOC. 
NO. 

4 

Glen  Ivy  (Teneccal) 
Hot  Spring 

ss 

6W 

10 

SB 

Lake   Mathevs 
(TH'l 

102 

USGS  WSP  336 

1915 

42 

Riverside 

3 

5 

102 

uses  WRI  33-73 

1974 

10 

77 

131 

USGS  Water  Res.  Dlv.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

»-ll 

Pilares  Hot  Sprlnqs 

4S 

3W 

12 

SB 

Perrls  (15') 

100 

USGS  P.P.  49? 

1965 

24 

171 

(Shown  as 
"Bemaecone"  o»i 
Perris  15'  quad  and 
"Lakevlew"  on  Ferris 
7)j*  quad.) 

(Bemasconl-Lakevlcw 

USGS  WSP  338 

191S 

40 

Riverside 

7 

6 

7 
S 

No  name 

3S 

2W 

7 

SB 

Sunnymead  (7)iM 

104 

USGS  WRI  33-73 

1974 

10 

84 

Hot  eprlnq 

IS 

2W 

33 

SB 

Lalcevlew  (7»i') 

USGS  Lakevlev  IH'   quad. 

No  other  iCTiown 
reference 

Men  Hot  Spring. 

3S 

?W 

23 

SB 

El  Cosco  (7),') 

90-110 

USGS  P.P.  492 

1965 

24 

172 

110 

USGS  WSP  338 

1915 

37 

Riverside 
8 

109 

USGS  WRI  33-73 

1974 

8 

35 

9 

Highland  Springs 

2S 

iw 

25 

SB 

Banning  (15-  ) 

112 

USGS  P.P.  492 

1965 

24 

172A 

112 

CJMG  V.  41  No.  3 

1945 

178 

10 

Gllnan  (San  Jacinto. 
Relief)  Hot  Springs 

4S 

IW 

9 

SB 

Banning  (15* ) 

83-116 

USGS  P.P.  492 

1965 

24 

173 

- 

USGS  WSP  336 

1915 

36 

Riverside 

9 

117 

USGS  WRI  33-73 

1974 

10 

85 

u 

Soboba  (Rltchey)  Hot 
Sprlnqs 

4S 

IE 

30 

SB 

Banning  (15') 

70-111 

USGS  P.P.  492 

1965 

24 

174 

Soboba  (Rltchey)  Hot 
Springs 

4S 

IE 

30 

SB 

Banning  (15') 

70-111 

USGS  WSP  336 

1915 

39 

Riverside 
10 

111, 
102 

USGS  WHI  33-73 

1974 

10 

80,  83 

2  sites 

llA 

»ell 

35 

4E 

2 

SB 

Palm  Springs 
(15') 

84 

OJMG  SR  94 

1966 

PI.  1 

IIB 

Kell 

3S 

4E 

2 

SB 

Palm  Springs 
(15M 

64 

CDMG  SR  94 

1968 

PI.  1 

1? 

Men 

2S 

5C 

29 

SB 

Thousand  Palms 

(15M 

166 

CDMG  SR  94 

1968 

PI.  1 

13 

Discovery  Well 

2S 

it. 

30 

SB 

Thousand  Palms 

(15M 

146 

154 

1934 

CDMS  SR  94 

1968 

42, 
PI.  1 

U 

Original  Bath  House 
Hell 

2S 

5E 

30 

SB 

Thousand  Palms 
(15') 

118 

170 

pre  1940 

CDMG  SR  94 

1968 

42. 

PI.  1 

15 

Coffee  Bath  House 
(4  MellB) 

2S 

5E 

30 

SB 

Palm  Springs 
(15M 

106-116 

157 

1940- 
1954 

CDMG  SB  94 

1956 

42, 

PI.  1 

16 

Chandler  well 

2S 

5E 

30 

SB 

Palm  Springs 
(15') 

125 

160 

pre  1950 

CXMG  SR  94 

1968 

42, 

PI.  1 

17 

Blue  Haven  Well 

?S 

5E 

30 

SB 

Thousand  Palms 
(15') 

130 

140 

pre  1950 

CDMG  SR  94 

1968 

42, 
PI.  1 

16 

Realty  Co.  of  Am, 
Deoo.  Well 

2S 

5E 

30 

SB 

Thousand  Palms 
(15M 

120 

212 

1952 

CDMG  SR  94 

1968 

42, 

PI.  1 

19 

Dorslc  Well 

2S 

5E 

30 

SB 

Thousand  Palms 
(15M 

120 

149 

1957 

CDMG  SR  94 

1968 

42, 
PI.  1 

20 

Necne  well 

2S 

5E 

30 

SB 

Thousand  Palms 
(15') 

104 

1?7 

1946 

CDM3  SR  94 

1968 

42, 

PI.  1 

}l 

Desert  Hot  Springs  Co. 
water  Dist.  wl 

}S 

5E 

30 

SB 

Thousand  Palms 
(15') 

66 

92 

1941 

CDMG  SR  94 

1968 

42, 
PI.  1 

n 

Desert  Hot  Springs  Co. 
Water  Dlst.  »6 

2S 

SE 

30 

SB 

Thousand  Palms 
(15') 

88 

90 

1955 

CDMG  SR  94 

1966 

42, 
PI.  1 

23 

Well 

?S 

5E 

30 

SB 

Thousand  Palms 
(15'1 

112-116 

300t 

USGS  P.P.  49? 

!"65 

24 

174A 

8  wells 

•  S«ft  Appendix  D   for    location. 


104 

SANTA  ANA  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


LOC. 
NO. 

NN<E 

LOCATICN 

eUUIOHSLE 

HATER 
TEMP. 
CF) 

TCTTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 
(see  list  of  references  for  abb 

, 

NOTES 

T 

R 

SEC. 

BU4 

PireLICATIOW 

YEAR 

PACE 

LOC. 

HO. 

?4 

Well 

2S 

5E 

30 

SB 

Thousand  Palms 
(15M 

116 

USGS  WRI  33-73 

1974 

8 

46 

?5 

NcCuUouqh  Well 

2S 

5E 

31 

SB 

Palm  Springs 
(15') 

S8 

220 

1940 
1954 

CDMG  SR  94 

1966 

42. 
PI.  1 

26 

Desert  Hot  Springs  Co. 
Water  Dist.  »3 

2S 

5E 

31 

SB 

Palm  Springs 
(15') 

us 

46 

1940 

CDMG  SR  94 

1966 

42. 
PI.  1 

^^ 

^sert  Hot  Springs  Co. 
Water  Dlst.  b5 

2S 

SE 

31 

SB 

Falm  Springs 
(15M 

9!:. 

b07 

1948 

CDMG  SR  94 

1968 

42, 
PI.  1 

28 

mr»cle  ".■■ 

25 

5E 

32 

SB 

Palm  Springs 
(15') 

14*:. 

143 

1948 

CDMG  SR  94 

1968 

42, 
PI.  1 

29 

Well  oe 

2S 

SE 

32 

SB 

Palm  Springs 
(15') 

142 

76 

19S2J 

CDfC  SR  94 

1968 

42, 

PI.  1 

30 

Hell  ail 

2S 

5E 

32 

SB 

Palm  Springs 
(15') 

146 

40 

1956 

CDMG  SI-  '1 

1968 

42, 
PI.  1 

31 

Well  «12 

2S 

5E 

32 

SB 

Paljn  Springs 
<15'  1 

134 

150 

19527 

CDH3  SR  94 

1968 

42, 
PI.  1 

32 

Well  «13 

2S 

5E 

32 

SB 

Palm  Springs 
(15') 

153 

165 

19527 

CDMG  SR  94 

1968 

42. 
PI.  1 

33 

Well  HIS  (Yerxa  HI) 

2S 

5E 

32 

SB 

Palm  Springs 
(15') 

12? 

90 

1940 

CDMG  SR  94 

1968 

42, 

PI,  1 

34 

Davis  Well 

2S 

5E 

32 

SB 

Palm  Springs 
(15') 

102 

128 

1949 

CDMG  SR  94 

196e 

42, 
PI.  1 

35 

lemplenan  017 

?S 

5E 

32 

SB 

Palm  Springs 
(15') 

156 

95 

1955 

CDMG  SR  94 

1968 

42, 
PI.  1 

36 

Angel  View  Crippled 
Childrens  Foundation, 
Inc.  aie 

2S 

5E 

32 

SB 

Palm  Springs 
(15') 

136 

138 

1955 

CDMG  SR  94 

1968 

42, 
PI.  1 

37 

Schwartz  «19 

2S 

5E 

32 

SB 

Thousand  Palms 
(15') 

150 

54 

1955 

CDMG  SR  94 

1968 

42, 
PI.  1 

38 

Well  «21  (YeDca  n> 

2S 

5E 

32 

S& 

Thousand  Palms 
(IS-) 

176 

200 

1940 

CDMG  SR  94 

1968 

42, 
PI.  1 

39 

Sullivan  1122 

2S 

5E 

3? 

SB 

Thousand  Palms 
(15') 

166 

161 

1956 

CDMG  SR  94 

1968 

42, 

PI.  1 

40 

Spring 

2S 

5E 

32 

SB 

Thousand  Palms 
(15M 

CDMG  SR  94 

1968 

42, 

footnote 
3 

"only  Surface  water 
in  area" 

41 

Highlands  Desert  Hot 
Springs  W9 

2S 

5E 

33 

SB 

Thousand  Palms 
(15') 

120 

165 

1955 

CDMG  SR  94 

1968 

42, 
PI.  1 

42 

Simone  and  Babin  «10 

2S 

5E 

33 

S», 

Thousand  Palms 
(15'> 

112 

136 

1954 

CDMG  SR  94 

1968 

42, 
PI.  1 

43 

Hubbard  ill 

3S 

5E 

5 

SB 

Thousand  Palms 
(15'1 

108 

16 

1946 

CDMG  SR  94 

1966 

42, 
PI.  1 

44 

Hubbard  n? 
(Bubbling  Wells) 

3S 

5E 

5 

35 

Thousand  Palms 
(15') 

108 

23 

1947 

CDMG  SR  94 

1968 

42, 

PI.  1 

4S 

Reeves  Well 

3S 

SE 

4 

SB 

Thousand  Palms 
(15') 

95 

76 

1949 

CDMG  SR  94 

1968 

42, 

PI.  1 

46 

Bannon  et  al  Well 

3S 

5E 

4 

sn 

TlQousand  Palms 
(15') 

90 

182 

1957 

CDMG  SR  94 

1968 

42, 

PI.  1 

47 

Ervln  and  Assoc  Well 

3S 

5E 

3 

SB 

Ibousand  Palms 
(15') 

98 

225 

1954 

CDMG  SR  94 

1968 

42. 
PI.  1 

46 

Terra  Vista  Corp. 
Well 

3S 

SE 

3 

SB 

Thousand  Palms 
(15'1 

94 

164 

1954 

CDMG  SR  94 

1968 

4?t 
PI.  1 

49 

Johnson  a? 

3S 

5E 

3 

SB 

Thousand  Palms 
(15') 

106 

147 

1955 

CDMG  SR  94 

1968 

42, 

PI.  1 

50 

Holmes  Well 

3S 

5E 

10 

SB 

Thousand  Palms 
<15') 

165 

80 

1951 

CDMG  SR  94 

1968 

42, 
PI.  1 

51 

Lucky  7  Well 

■S 

^E 

I'l 

1!,.  M.rand  Palms 

184 

83 

1950 

CDMG  SR  94 

1966 

42, 
PI.  1 

See  footnot*'  '  . 
p.  42 

188 

157- 
167 

1950 

CDHG  SB  94 

1968 

42, 

PI.  1 

200 

188- 
218 

1950 

CDBG  SR  94 

1968 

42, 
PI.  1 

1 

200 

- 

USGS  P.P.  497 

1965 

24 

174B 

for  location. 


1985 

SANTA    ANA    SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


105 


APPENDIX   B    -    TABULATED    LIST   OF    THERMAL    SPRINGS   AND  WELLS 


MAr 

uv, 

NO. 

NAME 

LOCATICW 

^^LiADBANGI£ 

WATER 
TEMP. 
CF) 

TCTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REreRENCE(S) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATION 

YEAR 

PACE 

LOC. 

NO. 

5? 

young  Well 

3S 

5E 

10 

SB 

Thousand  Palms 
(15M 

lie 

75 

1951 

CDHG  SR  94 

1968 

«2, 
PI.  1 

S? 

GuptlU  well 

3S 

5E 

10 

S3 

Thousand  Palms 
(15M 

106 

117 

1956 

CDMG  SR  94 

1968 

42. 

PI.  1 

56 

uell 

3S 

5E 

10 

S3 

TTiousand  Palms 
(15M 

176- 
208 

5001 

USGS  WRI  33-73 

1974 

8 

39-42 

4  wells 

«en 

IS 

5E 

11 

SB 

Thousand  Halms 
{15M 

190 

USGS  WRI  33-73 

1974 

B 

43 

bell 

3S 

5E 

11 

S3 

Thousand  Palms 
<15') 

178 

USGS  WRI  33-73 

1974 

6 

44 

57 

Lanciols  Well 

3S 

5E 

11 

SB 

Thousand  Palms 
(IS'l 

175 

no 

1953 

CDMG  SR  94 

1968 

42, 
PI.  1 

58 

Johnson  Ml  Well 

3S 

5E 

11 

S3 

Thousand  Palms 
(ISM 

175 

105 

1951 

CDMG  SR  94 

1968 

42, 
PI.  1 

59 

rtody  Wei  1 

3S 

5E 

11 

SB 

Ttiousand  Palms 
<15M 

150 

170 

1956 

CDMG  SR  94 

1968 

42, 
PI.  1 

60 

Tarbutton  well 

3S 

5E 

11 

S3 

Thousand  Palms 
US') 

125 

210 

1955 

CDMG  SR  94 

1968 

42, 
PI.  1 

See  footnote  6, 
p.  42 

61 

Kiel  Well 

3S 

5E 

14 

SB 

Thousand  Palms 
(15'1 

103 

265 

1951 

CDMG  SR  94 

1968 

42, 
PI.  1 

6! 

Simons  and  Bafcln  Well 

3S 

5E 

14 

SE 

Thousand  Palms 
(15') 

130 

146 

1953 

CDMG  SR  94 

1968 

42. 
PI.  1 

63 

Paddo<a(  well 

3S 

5E 

14 

S3 

Thousand  Palms 
(15') 

134 

220 

1956 

CDMG  SR  94 

1968 

42. 
PI.  1 

64 

wen 

3S 

5E 

e 

SB 

Thousand  Palms 
(15M 

B5 

- 

- 

CDMG  SR  94 

1968 

PI.  1 

65 

Well 

3S 

5E 

17 

SB 

Thousand  Palms 
(15M 

64 

CDM5  SR  94 

1968 

PI.  1 

65A 

well 

3E 

5E 

22 

SB 

Thousand  Palms 
(15') 

89 

CDMG  SR  94 

196B 

PI.  1 

66 

Well 

3S 

6E 

17 

SB 

Thousand  Palms 
(15') 

120 

- 

- 

USGS  WPI  33-73 

1974 

e 

45 

67 

Well 

3S 

6E 

21 

SB 

Thousand  Palms 
(15') 

112 

USGS  WRI  33-73 

1973 

e 

47 

67(1 

Palin  Springs 

4S 

4E 

14 

SB 

Palm  Springs 
(15') 

100 

USGS  P.P.  492 

1965 

24 

175 

(Aguas  Callentesl 

100 

USGS  WSP  338 

1915 

40 

Riverside 
11 

Agua  Caliente  Spring 

100 

USGS  WRI  33-73 

1974 

10 

60 

104 

USGS  Water  Res.  Oiv.  Open  File 
Report  (Colo.  Desert) 

1968 

11 

56 

obrlen  "Porter"  2 

6S 

liw 

2 

SB 

Newport  Beach 
IT,') 

"hot 

salt 
water" 

CDOG  written  comm. 

1974 

CDOG  Map  134 
Huntington  Beach 

69 

Beloil  "Davenport" 
Well 

6S 

llw 

2 

SB 

Newport  Beach 
(7),') 

"hot 
water" 

CDOG  written  corrm. 

1974 

70 

Fairview  Hot  Spring 

6S 

low 

10 

SB 

Newport  Beach 
(7!,') 

96 

USGS  P.P.  492 

1965 

24 

165 

TOA 

Well 

7S 

ew 

16 

SB 

San  Juan  Cap. 
(7>i') 

82 

CDWR  Bull.  106-2 

1967 

159 

71 

Well 

7£ 

7W 

34 

SB 

Canada 
Gobemadora  (A'  ) 

95 

CDWR  Bull.  106-2 

1967 

160 

7? 

San  Juar  (Caplstrano 
Hot)  Springs 

75 

ew 

4 

SB 

Canada 
Gobemadora  (Tlj") 

121- 
124 

USGS  P.P.  492 

1965 

24 

166 

San  Juan  Hot  Springs 

7S 

6W 

3 

SB 

123 

USGS  WRI  33-73 

1974 

8 

37 

(Loc.  corrected) 

San  Juan  Hot  Springs 

7S 

6W 

4 

SB 

120 

USGS  water  Res.  Div.  Open  File 
(So.  Coast  Transv.  &  Penln. 
Ranges ) 

1968 

A-10 

7! 

Wrervden  (Bundys 
Elsinorel  Hot  Springs 

es 

4W 

5 

SB 

Elslnore  (7)j'  ) 

lie 

USGS  P.P.  492 

1965 

24 

168 

well  on  site  of 
spring 

112 

USGS  WSP  338 

1915 

43 

Riverside 

4 

74 

Elslnore  Hot  Springs 

6S 

4W 

5 

SB 

Elslnore  (T!,') 

125 

USGS  P.P.  492 

1965 

24 

169 

Wells  on  site  of 
spring 

•  S«e  Appendix  D  for   location. 


106 

SANTA  ANA  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY  BULL.  201 

APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND   WELLS 


LOC. 
HO. 

NAME 

LOCATICK 

QUADRANGLE 

WATER 
TEMP. 
(Tl 

TOTAL 
DEPTH 
(FEET) 

YEAR 

DRILLED 

REFEI«NCE(S) 

, 

NOTES 

T 

R 

SEC. 

8U4 

PIJBLICATICW 

IfEAR 

PAGE 

WC. 

NO. 

74 

EUlnore  Hot  Springe 

6S 

4W 

5 

SB 

ElBlnore  (71)M 

125 

U5G5  WBl  33-73 

1974 

10 

76 

- 

USGS  WSP  336 

1915 

42 

Riverside 

5 

75 

Tenec\jla  Hot  Springs 

7S 

yu 

?3 

SB 

Hjrrleta  (Tie) 

116 

USG5  WRI  31-7' 

1974 

6 

36 

76 

Hirrleta  Hot  Springs 

7S 

3W 

14 

SB 

Itirrleta  ITlj') 

134- 
136 

USGS  P.P.  492 

1965 

24 

170 

136 

USGS  WSP  338 

1915 

44 

Riverside 
6 

132 

USGS  WRI  33-73 

1974 

8 

34 

Kirrlets  (Ramona)  and 
Bethesda  Hot  Spring 

96-117 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin, 
Ranges) 

1968 

A-11 

2  springs 

T7 

Well 

SS 

iw 

16 

SB 

Heinet  (Tl,-) 

in: 

USGS  WRI  33-7' 

76 

«»1I 

65 

iw 

4 

SB 

Hemet  (71,') 

80 

CDWR  Bull.  106-2 

1967 

167 

79 

Hot  Spring 

75 

JE 

23 
or  26 

SB 

IdyllwUd  (ISO 

Pers.  comm.  Bob  sharp,  USGS 

1972 

Near  border  of 
section  23  &    26 

SO 

Hall 

SS 

6E 

24 

SB 

Palm  Desert  (IS- ) 

162 

356 

USGS  WRI  33-73 

1974 

6 

?? 

60* 

Mall 

75 

9E 

16 

SB 

(*cca  (7!]') 

90 

CDWR  Bull  143-7 

1970 

86 

81 

De  Luz  warn  Springs 

8S 

4W 

32 

SB 

Fallbrook  (7%' ) 

64-88 

USGS  P.P.  492 

1965 

24 

177 

84-88 

USGS  WSP  338 

1915 

47-46 

San 
Diego  1 

85 

USGS  Water  Res.  Dlv.  Open  File 
(So.  Coast.  Transv.  &  Penin. 
Ranges) 

1968 

A-12 

61A 

Nell 

6S 

3E 

7 

SB 

Temecula  (73j') 

65 

CDWR  Bull.  106-? 

1967 

165 

62 

Agus  Tibia  Spring 

9S 

IW 

29 

SB 

Pala  (Tij") 

92 

USGS  P.P.  492 

1965 

24 

176 

92 

USGS  WSP  338 

1915 

47 

San 
Diego  2 

63 

well 

lOS 

IW 

23 

SB 

Boucher  Hill 
(71,') 

80 

CDWR  Bull.  106-2 

1967 

166 

83A 

Uamer  (Las  Aguas 
Csllentes)  Hot  Springs 

lOS 

3E 

24 

SB 

Warner  Springs 
(7H') 

131- 
139 

USGS  P.p.  49r 

1965 

24 

179 

139 

USGS  WSP  338 

1915 

45-46 

San 
Diego  4 

84 

Well 

8S 

6E 

13 

SB 

Oasis  (7>i'l 

90 

CDWR  Bull.  143-7 

1970 

PI.  2, 
90 

85 

well 

65 

9E 

19 

SB 

Oasis  (7S') 

109 

387 

USGS  WRI  33-7? 

1974 

6 

23 

e« 

Well 

8S 

9E 

29 

SB 

Oasis  (Tlf-l 

109 

CDWR  Bull.  143-7 

1970 

90 

102 

USGS  WRI  33-73 

1974 

6 

24 

67 

Well 

9S 

9E 

4 

SB 

Oasis  (TliM 

115 

CDWR  Bull.  143-7 

1970 

91 

115 

USGS  WRI  33-73 

1974 

8 

26 

68 

Fish  Sprlras 

95 

9E 

9 

SB 

oasis  (7.J.) 

Ml] 

USGS  l.i  .  4"-" 

1965 

25 

162 

- 

USGS  WSP  338 

1915 

315 

Imperial 
1 

69 

Holly  Hot  Wells 

105 

9E 

3'i 

SB 

Seventeen  Palms 
(71,.) 

136. 
142 

1980 

Rex  unpub. 

1972 

1 

73,  73A 

2  wells 

90 

Well 

lis 

9E 

2 

SB 

Shell  Reef  (TijM 

136 

CDWR  Bull.  14'- ■ 

1970 

PI.  2, 
92 

136 

USGS  WRI  13-73 

1974 

8 

31 

•   S««  Appendix  D   for    location. 


1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  107 

SANTA   ANA   SHEET  APPENDIX   B    -    TABULATED   LIST   OF    THERMAL   SPRINGS   AND  WELLS 


• 
KAF 
UX. 

NO. 

•,■." 

LOCATICN 

QUADRANGLE 

HATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEETl 

YEAR 
DRILLED 

B£raPENCE(S) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATION 

YEAR 

PAGE 

LOC. 
NO. 

91 

Mil 

US 

» 

n 

SB 

Valley  Center 
(71,-) 

81 

anm  Bull.  106-2 

1967 

193 

9? 

J.  Balch,    Ironwood 
Hotel  w«n 

12S 

BE 

e 

SB 

Borreqo  Htn. 

99 

335 

Rex  unpub. 

1972 

124 

93 

The**ate.  Circle  T. 
Trailer  Park.   Well 

12S 

SE 

6 

SB 

Borreqo   Mtn. 

98 

312 

Rex  unpub. 

1972 

123 

94 

H.A.    aaith   Well 

12S 

et 

b 

SB 

Borreqo  Mtn. 
(AM 

88 

300 

Rex  unpub. 

1972 

152 

95 

C.   Peterson  Well 

12S 

SE 

8 

SB 

Borreqo  Mtn. 
(7H') 

89 

285 

Rex  unpub. 

1972 

120 

96 

E.   Robinson   Wells 

12S 

SE 

9 

SB 

Borreqo   Mtn. 
(7H'  ) 

98 

209 

Rex  unpub. 

1972 

85/85A 

2  wells 

97 

A.   Williams  well 

12S 

BE 

15 

SB 

Borreqo  Mtn. 
171,M 

96 

148 

Rex  unpub. 

1972 

119 

99 

De  Anza  Trail   Inn 
Well 

12S 

e£ 

15 

SB 

Harper  Canyon 

lOO 

215 

Rex  unpub. 

1972 

89 

99 

Cornish  well 

12S 

8E 

22 

SB 

Harper  Canyon 

89 

229 

Rex  unpub. 

1972 

118 

lOO 

A.  1>oner  Well 

12S 

BE 

10 

SB 

Shell  Reef    <7!}') 

B9 

200 

Rex  unpub. 

1972 

153 

101 

I.M.   Jacobs   «3  Well 

12S 

9E 

22 

SB 

Borreqo   Mtn.   SE 

102 

1200 

Rex  unpub. 

1972 

90 

102 

T.H.  Jacobs  N2  Well 

12S 

9E 

23 

SB 

Borreqo  Mtn.  SE 
(•7>,M 

86 

670 

Rex  unpub. 

1972 

91 

103 

Landmark  Co. 

13S 

9E 

2 

SB 

Borreqo  Htn,  SE 
(THM 

95 

1185 

Rex  unpub. 

1972 

151 

SANTA   CRUZ   SHEET 


> 

Sarqent   Estate  war™ 
sprlnq 

lis 

4E 

31 

W 

Chittenden    (Tij') 

77 

USGS  Water  Res.  Div.  Open  File 
(So.   Coast,    Transv.   &   Penln. 
Ranges ) 

1968 

A-18 

2 

San  Benito  Mineral 
Well 

13S 

6E 

7 

H) 

Tres  Plnos   (Tij-  ) 

75 

USGS   P.P.    492 

1965 

22 

89A 

286 

early 
1890 -s 

USGS  WSP   336 

1915 

306-307 

San 
Benito   1 

Saline 

3 

Warm  spring 

13S 

lOE 

29 

ID 

Ortlqalita    115') 

81 

USGS  Water  Res.  Dlv.  Open  File 
(So.  Coast,  Transv,  A  Renin. 
Ranges ) 

1968 

A-8 

4 

Sulfxir  hot  sprlnq 

36-37. I'N 
121-50. 65'W 

Seaside   CA') 

100± 

USGS  Map  W-577 

1,74 

Sheet 
2  of    2 

Described  under 
Seaside  fault 

5 

Mercey  Hot  Sprlnqs 

14S 

lOE 

15 

»o 

Panocbe  Valley 
(15M 

79-109 

USGS  P.P.   492 

1965 

23 

132 

water  bradush 

USGS  WSP   338 

1915 

78-79 

Fresno 
8 

119 

USGS  Water  Res,  Dlv.  Open  File 
(So.  Coast,  Transv.  ft  Penln, 
Ranges ) 

1968 

A-4 

6 

War»  spring 

15S 

12E 

8 

H> 

Chounet  Ranch 
I7!,M 

75 

USGS  Water   Res,   Div.   Open   File 
(So.  Coast,   Transv.  4  Penin. 
Ranges) 

1968 

A-5 

7 

Hot  sprlnq 

18S 

IE 

26-27 

W) 

Big  Sur    (71j') 

114 

USGS   P.P.   492 

1965 

22 

90 

114 

USGS  WSP   338 

1915 

57 

Ptenterey 

1 

8 

Paralso  Hot  Sprlnqs 

les 

5E 

25 

M> 

Paralso  Springs 
(7!,M 

65-111 

USGS  P.P.   492 

1965 

22 

92 

118 

USGS  WSP   338 

1915 

60 

Monterey 

2 

98 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast,  Transv.  &  Penin. 
Ranges) 

1968 

A-e 

SA 

Sulphur  sprlnq 

les 

6£ 

30 

H) 

Paralso  Springs 
<71,'l 

87 

USGS  Water   Res.    Div.   Open  File 
(So.   Coast.    Transv.   S.    Penin. 
Ranges) 

1968 

A-e 

9 

Slates   Hot   Sprlnqs 

21S 

3E 

9 

W 

Lopez   Point    (71}') 

100- 
121 

US<;S  P.P.    492 

1965 

2? 

93 

110- 
121 

USGS  WSP   338 

1915 

56-57 

(txilerey 

4 

S««  Appendix  D  for  locatioo. 


108 

SANTA  CRUZ  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


HkF 
UK. 

NO. 

HAHE 

LOCATICH 

QUADRANGLE 

HATER 
TEHP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE (S) 

, 

NWES 

T 

R 

SEC. 

BfcH 

PUBLICATICM 

YEAR 

PAGE 

LOC. 

NO. 

9 

(Big  Sur  Hot  Springs) 

21S 

3E 

9 

K> 

Lopei   Point    nH-i 

116- 
122 

USGS  Water  Res.  Dlv.  Open  File 
(So.  Coast,   Transv.  &  Penin. 
Ranges) 

1968 

A-9 

10 

Dolans  Hot  Springs 

21S 

iE 

24 

W 

Lopez  Point    11^') 

100 

USGS   P.P.   492 

1965 

2! 

94 

USGS  WSP   338 

1915 

57 

Honterey 

5 

9B 

USGS  Water  Res.  Dlv.  Open  File 
{So.   Coast,    Transv.   s    Penln. 
Ranges ) 

1968 

A-9 

11 

Tasaajara  Hot  Springs 

19S 

4E 

32 

m 

Tassajara  Hot 
Springs   (7)5' ) 

100- 
140 

USGS  P.P.   492 

1965 

22 

91 

100- 
140 

USGS  WSP   338 

1915 

57-60 

Hanterey 
3 

119. 
134, 
144 

USGS  Water   Res.   Dlv.   Open  File 
(So.  Coast,   Transv.  &  Penln. 
Ranges) 

1968 

A-8 

3  springs 

12 

Fresno  Hot  Springs 

?os 

UE 

34 

H) 

Criest   Valley 
(15') 

88-97 

USGS  P.P.   492 

1965 

23 

13-1 

- 

USGS  WSP   338 

1915 

78 

Fresno 
9 

(Coallnqa  Mineral 
Springs) 

112 

USGS  Water  Res.   Dlv.  Open  File 
(So.  Coast,   Transv.  &  Penln, 

Ranges) 

1968 

A-5 

SANTA  MARIA  SHEET 


1 

Las  Cruces  Hot 
Springs 

5N 

32W 

22 

SB 

Solvang   (7^' ) 

67-97 

USGS   P.P.    492 

1965 

22 

101 

" 

USGS  WSP    336 

1915 

68 

Sta. 
Barb.   1 

(^viota  or  Sulphur 
Hot  Springs 

99 

USGS  Water  Res.   Dlv.  Open  File 
(So.  Coast,   Transv.   &   Penin, 
Ranges) 

1968 

A-16 

San  Marcos  Hot  Spring 

108 

USGS  WRI    33-73 

1974 

10 

88 

SANTA  ROSA  SHEET 


• 
HAP 

LOC. 

NO. 

NAME 

LOCATICK 

QUADRANGLE 

WATER 
TEHP. 

(T) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE (S) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATION 

YEAR 

PAGE 

LOC. 

NO. 

1 

Point  Arena  Hot 
Springs 

UN 

15W 

27 

m 

Point  Arena   (15') 

110- 
112 

USGS    P.P.    492 

1965 

21 

47 

110- 
112 

USGS  WSP   336 

1915 

82-83 

Mendocino 
33 

- 

CDMG  HIS  V.    21,    no.   4 

Apr. 
1968 

61 

* 

112 

USGS  Water  Res.  Dlv.  Open  File 
(No.   Coast  &   Klamath   Mtns.) 

1966 

24 

2 

Old  Ombaun  Hot 
Springs 

12N 

38' 
123- 

13W 

63'N 

10.4'W 

4 

H) 

Ombaun   (15*  ) 

Corps  of  Engineers 
Ombaun  15'   guad. 
1:62.500   scale 

1944 

cnly  ref,   to  "Hot 
Spring" 

3 

Hoods   (Fairmont)  Hot 
Springs 

UN 

12W 

14 

H) 

Hopland  (15M 

100 

USGS   P.P.    492 

1965 

21 

70 

Location  from  R.G. 
Strand,   pers.  coinn. 
1968 

- 

USGS  WSP   336 

1915 

82 

Sonoma  1 

4 

Highland  Springs 

13H 

9W 

31 

H> 

Highland  Springs 
(7!,M 

52-82 

USGS  P.P.   492 

1965 

21 

52 

max.  84 

USGS  WSP   338 

1915 

183-165 

Lalce  39 

5 

England  (Elliott) 
Springs 

12N 

9W 

8 

ff) 

Highland  Springs 
(7>lM 

76 

USGS  P.P.   492 

1965 

21 

53 

76 

USGS  WSP   338 

1915 

166 

Lalie  40 

Official  Map  of  Lak*  County 

1909 

CDHG  SF  Hap  Rm. 
Hap   file  H-B 

6 

K«ls«Yvllle  wells 

I  IN 

9W 

14 

K> 

Kelseyvllle   (Tlj'  ) 

78 

USGS   P.P.    49.'' 

1965 

21 

54* 

76 

before 
1915 

USGS  WSP   338 

1915 

IBl 

Lake    35 

Carbonated 

6A 

UnnaliVd   Spring 

\vt 

fr-J 

10 

m 

Lower  Lalte  (15') 

100 

USGS   WSP    3  IP 

1915 

191 

Lake    17 

1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  109 

SANTA   ROSA    SHEET  APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND  WELLS 


uv. 

NO. 

NAME 

LOCATION 

QUADRANGIE 

HATER 
TEMP. 

CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE (S) 

1 

NOTES 

T 

R 

SEC. 

B&H 

PUBLICATION 

YEAR 

PACE 

LOC. 
NO. 

6A 

Bear  S-rln,- 

13N 

8W 

10 

^o 

Lok-er  lake  (15') 

Lake  Co.  Map 

1909 

CDMG  SF  Map  Rm. 
Map  file  H-8 

- 

Carlsbad  Spring 

12N 

9W 

1 

^D 

Kelseyvllle  (7H') 

66-76 

USGS  P.P.  492 

1965 

21 

54 

85 

USGS  WSP  338 

1915 

187 

Lake  41 

? 

Sullivan  «1  Well 
E.B.  Tov-ne,  Operator 

12N 

BW 

IS 

fC 

Kelscy\'llle  (T!,') 

180 

6140 

1972 

C0M5  Geotherm.  Hotline 

Dec. 

1972 

9 

Kettenhofer.  nl  Well 

13N 

8W 

26 

H> 

Kelsey%'ille  (7^' ) 

7822 

1973 

CDMG  Geotherm.  Hotline 

Nov. 
197? 

10 

The  Geysers  Geothermal 
Field 

UN 

9W 

1,  11, 

12,  13, 
14 
6,  7 

n-20 
26-30 

MD 

The  Geysers  (7^' ) 
and 

Whispering  Pines 
(7S') 

- 

- 

CDHG  Map  G  6-1 

Aug. 

1974 

- 

- 

UN 

8W 

W 

11 

Rorabaugh  A-2 
Pacific  Energy  Cort'. 

UN 

9W 

14 

H) 

The  Geysers  (7^' ) 

steam 

7150 

1971 

CDMG  Hap  G  6-1 

Auo. 

1974 

" 

" 

One  of  several 
Rorabaugh  wells 

n 

Harry  JacV  Q 

UN 

9W 

12 

M> 

The  Geysers  C7Jj'  ) 

steam 

6091 

1968 

Koenig,  J.B.,  No.  Cal.  Geol. 
Soc.  Geysers  Field  Trip 

1968 

6-7 

The  3eysers 

UN 

9W 

13 

HD 

The  Geysers  (Tlj*) 

140  to 
boiling 

USGS  P.P.  492 

1965 

22 

72 

USGS  WSP  338 

1915 

83-88 

Sonoma  4 

112- 
212 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  i  Klamath  Htns.) 

1968 

32 

4  springs  listed 

14 

Signal  Oil  Co. 
Cobb  Mtn.  «1  Well 

UK 

3W 

!^ 

■■- 

The  Geysers  (Tlj') 

steam 

7500 

1967 

No.  Cal.  Geol.  Soc.  Fieldtrip 
to  The  Geysets-J.B.  Koenig 

1968 

6-7 

15 

Sulphur  Creek 

UN 

3W 

29 

MD 

The  Geysers  (7I3' ) 

120 

USGS  P.P.  492 

1965 

22 

73 

Vague  location 

16 

Little  Geysers 

UN 

SW 

33  or 
28 

m 

The  Geysers  (T';'  ) 

110- 
160 

USGS  P.P.  492 

1965 

22 

74 

Vague  location 

160 

USGS  WSP  338 

1915 

88.89 

Sonoma  5 

n 

Gordon  Hot  Springs 

UN 

8W 

3,  10 
or  11 

MJ 

Whispering  Pines 
(7^4') 

92 

USGS  P.P.  492 

1965 

21 

60 

Vague  location 

92,  100 

USGS  WSP  338 

1915 

93 

Lake  46 

■.= 

Castle  (>'i;is)  !tt 
Springs 

Whispering  Pines 

164 

USGS  P.P.  492 

1965 

21 

62 

164 

USGS  WSP  338 

1915 

91-B 

Lake  54 

Castle  Rock  Springs 

UN 

BW 

35 

MD 

163 

CDOG  TR  13 

1975 

49 

73 

1? 

Anderson  Springs 

UN 

ew 

25 

H3 

Whispering  fines 

145 

USGS  P.P.  492 

1965 

21 

63 

146 

USGS  WSP  338 

1915 

89-91 

Lake  55 

UN 

ew 

26 

W) 

128 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Htns.) 

1968 

19 

UN 

8W 

25 

MD 

126 

CDOG  TR  13 

1975 

49 

72 

JO 

Selgler  Springs 

12N 

ew 

24 

n> 

Clearlake 
Highlands  HH' ) 

126 

USGS  P.P.  492 

1965 

21 

59 

126 

USGS  WSP  338 

1915 

96-97 

Lake  49 

126 
108 

USGS  Hater  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Htns.) 

1968 

20 

2  springs  listed 

104- 
126 

CDOG  TR  13 

1975 

49 

69 

2'j* 

Biker  io^i  irr-.r.g 

12N 

6W 

16 

Lover  L-T.e  (  '  -j '  ) 

76 

USGS  Water  Res.  Uiv.  uperi  File 
(No.  Coast  s  Klanath  Mtns.) 

1968 

2. 

2! 

Howard  Springs 

12N 

7W 

30 

fC 

Whispering  Pines 
(7I,') 

48-110 

USGS  P.P.  492 

1965 

21 

5B 

110 

USGS  WSP  338 

1915 

95-96 

Lake  51 

'  Se*  Appendix  D  for  location. 


no 

SANTA  ROSA  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX   B   -    TABULATED    LIST   OF    THERMAL    SPRINGS   AND  WELLS 


NAP* 

LOC. 
NO. 

NAME 

LOCATICN 

QUADKAHSLE 

MATER 
TEMP. 
CF) 

TCTTAL 
DEPTH 
(FEET) 

YEAR 

DRILLED 

REFERENCE  (SI 

NOTES 

T 

R 

SEC. 

BUI 

PiraLICATION 

YEAR 

PACE 

LOC. 
NO. 

21 

Howard  Springs 

12N 

7W 

30 

m 

Whispering  Pines 

95-113 

CDOG  TB  13 

1975 

49 

7C 

22 

Spiers  (Capsey) 
Springs 

UN 

7W 

5 

M) 

Whispering  Pines 
(7>I') 

78,  84 

USGS  P.p.  49; 

1965 

21 

61 

74,  78 

USGS  WSP  338 

1915 

190-191 

Lake  52 

23 

Harbin  Springs 

UN 

7W 

20 

H> 

Whispering  Pines 
(7I,') 

90-120 

USGS  P.P.  492 

1965 

21 

64 

122 

USGS  WSP  336 

1915 

93-95 

Lake  56 

119 

uses  Water  Res.  D!v.  Open  File 
(No.  Coast  8  Klamath  Ktns. ) 

19S8 

19 

2  springs  listed 

120 

CDOG  TR  13 

1975 

49 

71 

24 

Skoggs  Spr:.-.  r 

ICN 

liw 

2i 

W> 

Skaggs  Springs 

120-135 

USGS  P.P.  49? 

1965 

21 

71 

135 

USGS  WSP  338 

1915 

81-82 

Sonoma  8 

ION 

liw 

25 

H) 

132 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Htns.) 

1968 

32 

?5 

Mark  West  Warm 
Springs 

8N 

8W 

U 

HD 

Hark  West  Springs 

60-62 

USGS  P.P.  492 

1965 

22 

75 

65-85 

USGS  WSP  338 

1915 

115 

Sonoma  1] 

67 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

31 

?6 

CaliEtcqa  rower  Co. 
Wells 

9N 

7W 

26 

HD 

Calistoga  <7^') 

89 

305 

USGS  WPI  n-71 

1973 

Table  4 
Fig.  3 

27 

we:: 

9N 

7W 

26 

n> 

Calistoga  (Tlj'  ) 

279 

max. 

2000 

1960- 
1961 

CDHG  SR  -?t 

1963 

11 

8 

3  wells 

28 

Well 

ew 

7W 

2 

VD 

Calistoga  (7i5' ) 

88 

USGS  WEI  13-73 

1973 

Fig.  3 

29 

Well 

9N 

7W 

26 

«D 

Calistoga  (75s') 

110 

207 

USGS  WRI  13-73 

1973 

Table  4 
Fig.  3 

WelKs) 

333 

2000± 

CDOG  TR  13 

1975 

48 

66 

3  wells 

30 

Well 

9N 

7W 

25 

HD 

Calistoga  (7ij'  ) 

HS 

14-1 

USGS  WRI  13-7- 

1973 

Table  4 
Fig.  3 

31 

Well 

9N 

6W 

31 

MD 

Calistoga  (7!i') 

68 

USGS  WRI  13-71 

1973 

Fig.  3 

32 

Well 

9N 

6W 

31 

«j 

Calistoga  {7J5') 

210 

USGS  WRI  13-71 

1973 

Table  4 
Fig.  3 

Pacheteau's  Calistoga 
Hot  SprlngB  (well) 

210 

152 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

26 

33 

Calistoga  Hot  Springs 

9N 

6W 

31 

M) 

Calistoga  (7>j' ) 

126-173 

USGS  P.P.  492 

1965 

22 

81 

126-173 

USGS  WSP  336 

1915 

108-109 

Nape  4 

126-172 

CDOG  TR  13 

i97r, 

48 

65 

34 

Wei: 

PN 

sw 

7 

HD 

r„ll;,tDg„  (71,') 

77 

245 

USGS  WRI  13-71 

1...71 

Tatlf  4 
Fla .  1 

^■ 

35 

Well 

eN 

6W 

4 

'  g«  (7>5') 

178 

207 

USGS  WRI  13-73 

1973 

Table  4 
Fig.  3 

^ 

36 

A«tno  SprlngB 

9N 

6W 

1 

W 

Aetna  Springs 
(71)') 

63-92 

USGS  P.P.  49.' 

1965 

22 

eo 

6  springs 

92 

USGS  WSP  336 

1915 

156-157 

Napa  2 

2   springs 

Sulphur  Spring, 
G.B.  tV-Il<-l 

91 

USGS  Water  Res.  Div.  Open  File 
(No,  Coast  4  Klamath  Mtns.) 

1968 

26 

Prom  old  nln«  shaft 

37 

Wei 

SN 

6W 

25 

K) 

St.  Helena  (71,') 

10 

USGS  WRI  13-7 

1171 

Fig.  1 

. 

thlllpB  Soda  Springs 

»H 

4W 

25 

m 

Chiles  Valley      • ■  .   t 
(71,' ) 

USGS  P.P.  49. 

9U 

•  S««  Appcnidx  for   location. 


1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  1 1 1 

SANTA    ROSA    SHEET  APPENDIX   B    -    TABULATED   LIST   OF   THERMAL   SPRINGS   AND  WELLS 


vx- 

NO. 

KAME 

LOCATIOW         ] 

gUASRAHSLE 

WATLR 
TEMP. 
(T) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCK(S) 

,         1 

NOTES 

T 

R 

SEC. 

B«M 

PUBLICATION 

YEAR     PAGE 

LOC. 
NO. 

38 

Philips  Soda  Sprlnqs 

8N 

4W 

25 

m 

Chiles  Valley 

- 

USGS  WSP  338 

1915 

161-162 

Napa  8 

)« 

Napa  Rock  (Priests) 
Soda  Springs 

ew 

4W 

?5 

K) 

Chiles  Valley 
(7H') 

79 

USGS  P.P.  492 

1965 

22 

83 

79 

USGS  WSP  338 

1915 

lei 

Napa  9 

79 

USGS  Water  Res.  Dlv.  Open  File 
(No.  Coast  &  Klamath  Mtna.) 

1968 

26 

40 

ptlEwan  Ranch  warn 
Springs 

6N 

6W 

6 

>n 

Kenwood  (71,') 

BO 

USGS  P.P.  49? 

1965 

22 

77 

HcCwan  Ranch  on 
1908  Sonoma  Co.  map, 
CDMG  SF  map  file 

- 

USGS  WSP  338 

1915 

114-115 

Sonoma 
14 

73 

USGS  Water  Res.  Dlv.  Open  File 
(No.  Coast  &  Klamath  Mtns. ) 

1966 

31 

41 

Los  OulUcos  Warsi 
Sprlnqs 

6N 

6W 

5 

m 

Ken»ood  (7!)') 

78,  82 

USGS  P.P.  492 

1965 

22 

76 

78.  82 

USGS  WSP  338 

1915 

114 

Sonoma 
15 

Los  Gutllcos 
(n>rtcn's)  Warn 
Springs 

84,  87 

USGS  Water  Res.  Dlv.  Open  File 
(No.  Coast  4  Klamath  Htns.) 

1968 

31 

3  springs  listed 

42 

"Eldrldg«  State  Hosie" 
Warn  Springs 

6N 

6W 

22 

M) 

Glen  tllen  (Tij-) 

72 

USGS  P.P.  492 

1965 

22 

78 

72 

USGS  WSP  338 

1915 

114 

Sonoma 
16 

Scnoa«  State  Hoiw 

Warn  Spring 

70 

USGS  Water  Res.  Dlv.  Open  File 
(No.  Coast  t.   Klamath  Htns.) 

1966 

31 

45 

St.  Helena  White 
Sulphur  Spring 

711 

ew 

2 

M) 

Rutherford  (7)j'  ) 

69-90 

USGS  P.P.  492 

1965 

22 

62 

max. 
90 

IlSr,'!  WSP  338 

1915 

254-255 

Napa  10 

Spring 

90 

USGS  WRI  13-73 

1973 

51 

White  Sulphur  Springs 

7B 

6W 

? 

M} 

Rutherford  (71jM 

96 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1966 

25 

44 

Agua  Callente  Springs 

eN 

6W 

35 

H) 

Sonoma  <7)jM 

97-115 

USGS  P.P.  492 

1965 

22 

79 

max. 
114 

3001 

USGS  WSP  338 

1915 

113-114 

Sonoma 
16 

Several  wells 

45 

Fetters  Hot  Springs 

6« 

6W 

35 

« 

Sonoma  (T!,') 

100 

USGS  P.P.  492 

1965 

22 

79 

4  wells 

- 

USGS  WSP  338 

1915 

114 

Sonoma 
19 

46 

Boyes  tChms)  Hot 
Springs 

5N 

6W 

1 

M> 

Sonoma  <7»j*) 

114-116 

US(3S  P.P.  492 

1965 

22 

79 

Water  from  4  wells 

114-118 

200± 

USGS  WSP  336 

1915 

112-113 

Sonoma 
20-21 

2  wells 

112 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

31 

47 

Well 

TN 

5W 

3 

If) 

Rutherford  (7)j') 

77 

USGS  WRI  13-73 

1973 

Fig.  3 

4e 

Well 

TN 

5W 

15 

rc 

Rutherford  (7%' ) 

70 

USGS  WPl  13-73 

197) 

Fig.  3 

49 

Well 

7N 

5W 

14 

H> 

Rutherford  (T)}') 

69 

USGS  WRI  U-73 

1973 

Fig.  3 

50 

Well 

7N 

5W 

26 

K) 

Rutherford  (7!,M 

80 

US(a  WRI  13-73 

1973 

Fig.  3 

51 

well 

7)1 

5W 

26 

ICI 

Rutherford  {7)}*) 

85 

USGS   WRI  13-73 

1973 

Table  4 
Fig.  3 

5? 

Well 

6N 

4W 

23 

N) 

Napa  (T),') 

85 

USGS  WRI  13-73 

1973 

Fig.  3 

55 

Well 

6N 

4W 

24 

H) 

Napa  (7ij'  ) 

76 

USGS  WRI  13-73 

1973 

Fig.  3 

54 

Hot  spring 

(th 

4W 

34 

fC 

Napa  ITH'  ) 

83 

Napa  City  water  Dept. 
pers.  com.  5/5/72 

•  S«e  Appendix  D   for    locAt.lon. 


112 


SUSANVILLE  (wESTWOOD)  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY  BULL.  201 

APPENDIX   B   -    TABULATED   LIST   OF    THERMAL    SPRINGS   AND  WELLS 


• 
MAP 

UX. 

NO. 

NANE 

LOCATICN 

OUkSIWNGLE 

HATER 
TEMP. 
CFl 

TOl-AL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  CSl 

NOTES 

T 

R 

SEC. 

BtH 

PireLICATlCN 

YEAR     PAGE 

LOC. 
NO. 

I 

Sel licks  Springs 

31N 

15E 

7 

H> 

Karlo  (ISM 

72 

USGS  WSP  336 

1915 

324 

Lassen  9 

2 

Tlpton(s)  Springs 

31N 

15E 

37 

fD 

Karlo  I15M 

70 

USGS  P.p.  49.'' 

1965 

20 

29A 

Location  not  precise 

- 

USGS  WSP  338 

191S 

324-325 

Lassen 
10 

3 

Upper  mil  creek 
Springs 

JON 

4E 

21-22 

fO 

Lassen  Peak  (IS'} 

120-150 

USGS  P.P.  492 

1965 

20 

25 

Carnegie  Inst.  Wash.  Pub.  360 

192S 

90 

4 

Tophet  Hot  Springs 

30N 

4E 

21 

H) 

Lassen  Peak  (15*) 

175  to 
boiling 

USGS  P.P.  492 

1965 

20 

26 

(Soupan,  Supan) 

USGS  WSP  338 

1915 

141 

Shasta 
15 

5 

Busipas  Hot  Springs 

30N 

4e 

14 

M> 

Lassen  Peak  (15' ) 

boiling 

USGS  P.P.  492 

196S 

20 

27 

(Bunpss  Hell) 

- 

USGS  WSP  338 

1915 

140-141 

Shasta 
16 

6 

Morgan  Hot  Springs 

29N 

4E 

11 

m 

Lassen  Peak  (15' ) 

90-200 

USGS  P.P.  492 

1965 

20 

33 

200* 

USGS  WSP  338 

191S 

138-139 

Tehama  2 

7 

Growler  Hot  Springs 

29N 

4E 

n 

W) 

Lassen  Peak  (15') 

203. 

USGS  P.P.  440-F 

1963 

40-41 

5 

e 

Devils  Kitchen 

30N 

5E 

?i 

rt) 

Mt.  Harkness 
(15') 

150-205 

USGS  P.P.  49? 

1965 

21 

34 

- 

USGS  WSP  338 

1915 

141-142 

Plumas  1 

9 

Hot  Spring  valley 

30N 

5E 

22-27 

H) 

Mt.  Harkness 
(IS') 

83 

USGS  P.P.  492 

1965 

21 

35 

83 

USGS  WSP  336 

1915 

227 

Plumas  2 

Carbonated 

10 

Drake  Hot  Springs 

30N 

5E 

22 

M) 

Mt.  Harkness 
(15') 

123-148 

USGS  P.P.  492 

1965 

21 

36 

(Drakeshad ) 

146 

USGS  WSP  3  38 

1915 

142-143 

Plumas  4 

11 

Boiling  Spring 
Tartarus  Lake 

30N 

5E 

27 

m 

Kt.  Harkness 
(15') 

170-190 

USGS  P.P.  492 

1965 

21 

37 

170 

USGS  WSP  338 

1915 

143 

Plumas  5 

1? 

Terminal  Geyser 

30N 

5E 

36 

fC 

Mt.  Harkness 
(15') 

120-205 

USGS  P.P.  49? 

1965 

21 

38 

The  Geyser 

- 

USGS  WSP  338 

1915 

143-144 

Plumas  6 

13 

Geysers  Steam  Co., 
Terminal  Geyser  Well 

30N 

SE 

36 

M3 

Mt.  Harkness 
(15') 

265 

1270 

1962 

CDMG  SR  75 

1963 

n 

3 

14 

Roosevelt  Swimming 
Pool  Hell 

29N 

IJE 

6 

FC 

Susanville  (IS') 

96 

295(7) 

CDOG  TR  15 

1974 

Table  3a 

1 

97 

CDOG  TR  13 

1975 

47 

27 

15 

Church  of  Latter  Day 
Saints  Well 

J9N 

12E 

67 

M) 

Susanvllle  (15') 

120 

593 

CDOG  TR  15 

1974 

Table  3a 

2 

location  uncertain 

L.D.S.  Church  Well 

29N 

12E 

57 

H> 

120 

593 

CDOG  TR  13 

1975 

47 

26 

Location  uncertain 

16 

Wrl! 

30N 

1?E 

3? 

«> 

Susanville  (15') 

128 

Pers.  comm.  J.B. 

Koenlq 

17 

mller  custon  inrk 
Well 

J9N 

12E 

5 

Ml 

Susanville  (IS'  ) 

lis 

CDOG  TR  13 

1975 

47 

29 

1282 

Pers.  comm.  J.B. 
Koenlo 

18 

Shaffer  (Branbacks) 
Hot  Springs 

?9N 

15E 

23  (  24 

ff> 

Litchfield  (15') 
and  Wendel  (15' 1 

160-204 

USGS  P.P.  49? 

1965 

?0 

30 

Sec.  24  on  Wendel 
quad. 

Litchfield  (15') 
«K)  Wendel  (IS') 

204 

USGS  WSP  338 

1915 

124-126 

Lassen 
16 

Sec.  24  on  Wendel 
guad. 

•    S««  Appendix  D  for    location. 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


113 


sus/ 

NVILLE    (WESTWOOD)    S 

Hbtl 

APPENDIX   B   -    TABULATED   LIST   OF    THERMAL   SPRINGS   AND  WELLS 

LOC 
NO. 

NAME 

LOCATION 

OUAORANGLE 

WATER 
TEMP. 
CD 

TOTAL 
DEPTH 
(FEET) 

IfEAR 

DRILLED 

REFERENCE (S) 
(see    list   of   references    for   abbreviations) 

NC^ES 

T 

R 

SEC. 

BiM 

PUBLICATION 

YEAR 

PACE 

ux:. 

NO. 

18 

Wendel  Hot  Springs 

29N 

15E 

23 

W 

Litchfield  (ISM 

205 

CDOG  TR    13 

1975 

47 

30 

205 

CDOG  TR   15 

1975 

Table  3n 

3 

19 

HeglM   Power  Co. 
Wendel   Well 

29N 

15E 

23 

rf> 

Litchfield    (15') 
and  Wendel    (15' 1 

174 

630 

1962 

COMG  SR    ■" 

1963 

11 

4 

Hell 

147 

623 

CDOG  TR   13 

1975 

47 

31 

ro 

S.P.  Railroad  Well 

29N 

16£ 

30 

ro 

wendel    (15') 

83 

305 

axxs  TR  15 

1974 

Table    3a 

4 

.■■i 

Maqma  Power  Co.  Wells 

JSN 

leE 

e  (  s 

« 

Wendel    (15-) 

220 

116 

1962 

CDMG  SR   75 

196-' 

11 

5 

3  wells 

Wells 

26N 

16E 

4  t  8 

K) 

225 

1102 

CDOG  TR   13 

1975 

47 

33 

'' 

AJnedee  Hot  Springs 

2SN 

16E 

e 

hD 

Wendel    (15' 1 

178-204 

USGS  P.P.   492 

1965 

20 

31 

172-204 

USGS  WSP   338 

1915 

127 

Lassen  17 

204 

aX>G  TR   15 

1974 

Table  3a 

5 

203 

CDOG  TR   13 

1975 

47 

32 

ji 

Warm   springs 

25N 

SE 

13-14 

H) 

Almanor    (15' ) 

80-98 

USGS   P.P.   492 

1965 

21 

40-41 

Vague  locations 

24 

Kryger  Hot  Springs 

26N 

9E 

2 

«) 

Greenville   (15') 

90-106 

US(;S   P.P.   492 

1965 

21 

39 

Shown   as   Indian 
Valley  Hot  Springs 
on   Greenville  quad. 

(Indian  Valley) 

94 

USGS  WSP   338 

1915 

128 

Plumas  11 

25 

HlghrocJc   Spring 

28N 

17E 

25 

«) 

Doyle   (15') 

86 

USGS   P.P.   492 

1965 

20 

32 

86, 

1007 

USGS  WSP   338 

1915 

128 

Lassen  19 

TRONA   SHEET 


• 

NAME 

LOCATICH 

QUADRANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE  (S) 

NOTES 

T 

R 

SEC. 

BiM 

PUBLICATION 

YEAR 

PAGE 

tj3C- 
NO. 

1 

Baintex  Spring 

24S 

4  3E 

18 

Hi 

Trona   (15') 

92 

CDWR  Bull.   91-17 

1969 

67 

2 

Well 

24S 

4  3E 

9 

H) 

Trona   (15') 

136 

CDWR   Bull.   91-17 

1969 

66 

137 

600 

USGS  WRI    33-73 

1974 

6 

16 

3 

Well 

24S 

43E 

22 

H) 

Trona    (15') 

90 

297 

COWR  Bull.   91-17 

1969 

67 

4 

Hell 

25S 

43E 

9 

fC 

Trona   (15') 

86 

CDWR  Bull.   9l-l-r 

1969 

68 

5 

Sprlnq 

22N 

7E 

30 

SB 

Shoshone   (15') 

Very  warm  spring, 
B.w.  Troxel  pers. 
coma. 

6 

Spring 

21N 

7E 

30 

SB 

Shoshone    (15" ) 

Warm  artesion  spring, 
B.w.   Troxel   pers. 

conrn. 

7 

Tecopa  Hot  Springs 

21N 

7E 

33 

SB 

Tecopa   (15') 

109 

USGS  P.P.    492 

1965 

24 

146 

109 

US(S  WSP   338 

1915 

137 

Inyo  35 

108 

USGS  WRI    33-73 

1974 

10 

61 

H»9u  Power  Co.   test 

well 

- 

422 

1962 

CDNG  SK   7S 

1963 

11 

13 

e 

iKell 

21N 

7E 

28 

SB 

Tecopa   (15') 

118 

400 

USGS  WRI    33-73 

1974 

10 

62 

Flowing  well   drilled 
by  Stauffer  Chemical 
Co.,  B.w.  Troxel 

pers.  COMB. 

9 

Yeo«an  Hot   Springs 

21N 

7E 

1 

SB 

Tecopa    (15' > 

80 

uses  P.P.   492 

1965 

24 

145 

10 

Besting   Spring 

21N 

BE 

31 

SB 

Tecopa   (15- ) 

80 

USGS  P.P.    492 

1965 

24 

147 

80 

USGS  WSP   338 

1915 

319-320 

Inyo  34 

i  •  See  Appendix  D  for  location. 


114 

TRONA   SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


HAP 

LOC. 
NO. 

NAME 

LOCATICW 

QUADRANGLE 

WATER 
TEMP. 
CF) 

1 — 

TOTAL 
DEPTH 
(PEETl 

YEAR 
DRILLED 

refeic:hce(s) 
(see  list  of  references  for  abbreviations) 

NOTES 

T 

R 

SEC. 

BKM 

PUBLICATION 

YEAR 

PAGE 

LOC. 

NO. 

11 

Mil 

?6S 

39E 

19 

W> 

Inyokem  ( 15 ' ) 

87 

367 

CDWR  Bull.  91-9 

1963 

148-149 

1."' 

Well 

?6S 

39E 

?4 

H) 

Rldqecrest  (15' 1 

86-93 

825 

CDWR  Bull.  91-9 

1963 

151 

U 

Well 

27S 

40E 

7 

m 

Rldgecrest  (ISM 

86 

410 

CDWR  Bull.  Ol-u 

1963 

185 

14 

Well 

26S 

40E 

?? 

H) 

Ridgecrest  (15*1 

90 

830 

CDWR  Bull.  91-9 

1963 

169 

15 

Sorstoqs  Spring 

ISM 

5E 

? 

SB 

AvawAtz  Pass 
(15M 

82 

USGS  P.P.  492 

1965 

24 

154 

82 

USGS  WSP  338 

1915 

137-138 

San 
Bern.  3 

16 

Magma  Power  Co.  well 

?9S 

41E 

J5 

HJ 

Klinker  Htn. 
(TS'l 

241 

772 

CDMG  SR  75 

1963 

11 

14 

"Steam  Mell" 

205 

415 

1920± 

US(a  P.P.  457 

1964 

56 

Drilled  as  a  prospect 
for  mercuTY 

17 

Parfidlse  Spring 

12N 

JE 

7 

SB 

Lone  Mtn.  (15') 

85-106 

USC^S  P.P.  49? 

1965 

?4 

155 

102 

US(»  WSP  338 

1915 

52-53 

San 
Bern.  9 



102 

US(;S  WRI  33-73 

1974 

10 

63 

UKIAH  SHEET 


1 

Sulphur  Spring  near 
Laytonvllle 

21N 

15W 

1 

hD 

Laytonvllle  (15'  ) 

70 

USGS  P.P.  492 

1965 

21 

45A 

Water  contains  H^S 

- 

USGS  WSP  338 

1915 

259 

Mendocino 
4 

70 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  S  Klamath  Mtns.l 

1968 

25 

1« 

Jackson  valley  md 
Springs 

21N 

ISW 

19 

MD 

Cahto  Pealt  (T^i') 

80 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

25 

2 

Crabtree  Hot  Springs 

17N 

9W 

25/36 

Ml 

Lake  Pillsbury 
(15') 

66-105 

USGS  P.P.  492 

1965 

21 

48 

105 

USGS  WSP  338 

1915 

106-107 

Lake  5 

17N 

9W 

36 

m 

IDS 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  »  Klamath  Mtns.l 

1968 

22 

3 

Fouta  Springs 

17N 

7W 

5 

m 

Stonyford  (15* ) 

60-75 

USGS  P.P.  492 

1965 

21 

48A 

75 

USGS  WSP  338 

1915 

205-207 

Coluaa  3 

Carbonated  springs 

(Red  eye  Springs) 

78 

USGS   Water  Res.  Div.  Open  File 
(No.  Coast  ft  Klamath  Mtns.) 

1968 

16 

4 

Orrs  Hot  Springs 

16N 

14W 

24 

W) 

Boonvllle  (15' > 

63-104 

USGS  P.p.  492 

1965 

21 

45 

2  springs 

104 

USGS  WSP  338 

1915 

83 

Mendocino 
20 

Hot  Springs,  Alfred 
weger 

104 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

?4 

5 

Vichy  Springs 

15N 

12W 

14 

M> 

Ukiali  (15-  ) 

50-90 

USGS  P.P.  49? 

1965 

21 

46 

90 

USGS  WSP  338 

1915 

171-173 

Mendocino 
24 

85 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  1  Klamath  Mtns.) 

1968 

24 

6 

wells  (Cal.  Dri  Ice 
Co.) 

UN 

12W 

1 

n> 

Ukiah  (15') 

- 

350- 
790 

- 

USGS  WSP  1548 

1965 

6? 

7  wells  assoc.  with 
hot  ground  w.iter  ; 
location  vague 

7 

Sods  Bay  Springs 

13» 

ew 

6 

m 

Lucerne  (71j') 

80-87 

USGS  P.P.  49? 

1965 

?1 

55 

90,  124 

USGS  WSP  338 

1915 

191-192 

Lake  36 

S««  Appendix  D  for  location. 


1985 

UKIAH    SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  1 15 

APPENDIX   B   -    TABULATED    LIST   OF    THERMAL    SPRINGS   AND  WELLS 


• 
HAP 
LOC. 
NO. 

NAME 

LOCATICW 

OUADRANGIZ 

WATEK 
TEMP. 
CF) 

TCO-AL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

REFERENCE (S) 

NOTES 

T 

R 

SEC. 

B&H 

P(raHCATION 

YEAR 

PAGE 

LOC. 
NO. 

7 

CBlg  Soda  Spring) 

UN 

8W 

6 

ICl 

Lucerne  (Tlj') 

- 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  ft  Klamath  MthS.) 

1968 

20 

e 

Spring  (unnamwl) 

16N 

SW 

3S 

m 

Cle«rl«ke  Oaks 
US') 

90 

US(^  P.P.  492 

1965 

21 

49 

Location  vague 

9 

Springs 

16N 

8W 

35 

» 

Clearlake  0«k» 
(ISM 

72-92 

uses  p.p.  492 

196S 

21 

50 

92 

USGS  WSP  338 

1915 

202 

Lake  8 

Car1»nate<J  spring 

10 

Sulphur  Bank  Sprlngi 

13N 

7W 

5 

HI 

Cleerlake  Oeks 
<15') 

83-120 

USGS  P.P.  492 

1965 

21 

57 

(Hot  Balata) 

120 

USGS  WSP  338 

1915 

98-99 

Lake  38 

(Borax  Springs) 

157 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  i   Klamath  Mtns. ) 

1968 

20 

Zn  Sulphur  Bank  nine 

86-122 

CDOG  TI!  13 

1975 

49 

67 

u 

Well  (Mfloiflft  Power  Co.) 

13N 

TV* 

5 

rc 

Clearlake  Oaks 
(ISM 

367 

1391 

1961 

CDMG  SR  75 

1963 

11 

6 

367 

5016 

CDOG  Til  13 

1975 

49 

68 

12 

Spring 

14N 

7W 

36 

H) 

Clearlake  Oaks 
(ISM 

BO 

Ciancanelli  unpub.  map 

13 

Spring 

14N 

7W 

14 

le 

Clearlake  Oaks 
(ISM 

66-70 

Ciancanelli  unpub.  map 

14 

Chalk  Mtn. 

14N 

7W 

12 

tv 

Clearlake  Oaks 
(ISM 

67-70 

USGS  P.P.  492 

1965 

21 

51A 

In  altered  lava 

67-70 

US(3S  WSP  33B 

191S 

196-197 

Lake  25 

Carbonated  springs 

15 

CoB^lexlon  Springs 

15N 

ew 

3 

m 

Clearlake  Oaks 
(ISM 

74 

USGS  P. P. 492 

196S 

21 

SI 

- 

USGS  WSP  338 

191S 

297-298 

Lake  14 

Saline  springs 

Complexion  Springs 

15N 

6W 

3 

H) 

Clearlake  Oaks 
(15M 

- 

USGS  Water  Res.  Div,  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

21 

16 

Deadshot  Springs 

14N 

5U 

e 

WD 

Wilbur  Springs 
(ISM 

67-79 

VSGS   P.P.  492 

1965 

21 

65 

78 

USGS  WSP  338 

191S 

195 

Colusa  6 

Carbonated  spring 

60 

US(;s  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

15 

17 

Springs  at  Elgin  Mine 

14N 

ew 

13 

fC 

Wilbur  Springs 
(ISM 

140-1S3 

USGS  P.P.  492 

1965 

21 

69 

140-153 

US(3S  WSP  338 

1915 

104-106 

Colusa  7 

le 

Spring  at  Abbott  Mine 

14N 

5H 

31 

m 

Wlllsur  Springs 
(ISM 

79 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

21 

Mercury  mine 

19 

Blancks  Hot  Springs 

14N 

5W 

29 

K) 

Wilbur  Springs 
(ISM 

120 

USGS  P.P.  492 

1965 

21 

66 

. 

USGS  WSP  338 

1915 

104 

Colusa  12 

?0 

Springs  on  Manaanlta 
Hlning  property 

14N 

SW 

29 

m 

Wilbur  Springs 
(ISM 

110-142 

USGS  P.P.  492 

1965 

21 

67A 

110-142 

USGS  WSP  338 

191S 

104 

Colusa  10 

21 

Wilbur  (Sinmons)  Hot 
Springs 

14N 

5W 

26 

w 

Wilbur  Springs 
(ISM 

65-140 

USGS  P.P.  492 

1965 

21 

68 

140 

USGS  WSP  338 

1915 

99-103 

Colusa  9 

120 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

1968 

15 

3  springs  listed 

22 

Jones  Hot  Springs 

14N 

SW 

28 

H) 

Wilbur  Springs 
(ISM 

125 

USGS  P.P.  492 

196S 

21 

67 

- 

USGS  WSP  338 

1915 

103 

Colusa  11 

•  See  Appendix  D   for    location. 


116 

WALKER  LAKE  SHEET 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


APPENDIX  B  -  TABULATED  LIST  OF  THERMAL  SPRINGS  AND  WELLS 


• 
KM- 

LOC. 

NO. 

NME 

LOCATICH         ] 

CUADRMIGlE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 

DRILLED 

REFERENCE  (S) 
(see  list  of  references  for  abbreviations) 

NOTES 

T 

R 

SEC. 

BtH 

PUBLICATION 

YEAR 

PAGE 

LOC. 

NO. 

1 

Grovers  Hot  Springs 

ION 

19E 

24 

HJ 

Harkleevllle 
US') 

128-146 

USGS  P.P.  492 

1965 

23 

113 

128-146 

USGS  WSP  338 

1915 

131 

Alpine  1 

147 

CDOG  TR  13 

1975 

48 

48 

! 

Fflles  Hot  Sprinqs 

6N 

J  IE 

24 

to 

Fales  Hot  Springs 
(15') 

97-141 

USGS  P.P.  492 

1965 

23 

114 

129-141 

uses  WSP  338 

1915 

132 

Mono  1 

176 

CDOG  TR  13 

1975 

48 

49 

3 

MflcFw)  Power  Co.  Well 

6N 

23E 

24 

WJ 

Fales  Hot  Springs 
(15') 

- 

413 

1962 

CDMG  SR  75 

1963 

11 

9 

4 

Buckeye  Hot  Springs 

4N 

24E 

4 

MD 

Hatterhom  PeaJc 
115M 

140 

USGS  P.P.  492 

1965 

23 

115 

140 

USGS  WSP  338 

1915 

132-133 

Mono  2 

Extensive  lime 
carbonate  deposits 

140 

CDOG  TB  13 

1975 

48 

50 

5 

Travertine  Hot 
Springs 

5N 

25E 

54 

rt> 

Bodle  (15'1 

121-148 

USGS  P.P.  492 

1965 

23 

116 

148 

USGS  WSP  336 

1915 

133-135 

Mono  3 

122-149 

CDOG  TR  13 

1975 

48 

51 

6 

The  Hot  Springs 

AN 

25E 

9 

«) 

Bodie  (15') 

70-105 

USGS  P.P.  492 

1965 

23 

117 

70-105 

USGS  WSP  338 

1915 

133 

Hjno  4 

95-113 

CDOG  TR  13 

1975 

48 

52 

7 

Magma  Power  Co.  Well 

4N 

25E 

9 

H3 

Bodie  (15'  ) 

122 

982 

1962 

CDMG  SB  75 

1963 

11 

10 

7* 

Magma  Power  Co.  Well 

5N 

25E 

32 

Wl 

Bodie  (15') 

122 

924 

1962 

CDOG  TR  1 3 

1975 

4B 

53 

8 

Warm  Sprinqs  Flat 

4N 

26E 

le 

Ki 

Bodle  (15') 

100 

USGS  P.P.  492 

1965 

23 

lie 

- 

USGS  WSP  338 

1915 

135-136 

Mono  5 

9 

Near  Mormon  Creelc 

4N 

26E 

16 

H) 

Bodle  (15' ) 

100 

USGS  P.P.  492 

1965 

23 

119 

USGS  WSP  338 

1915 

135-136 

Mono  5 

10 

Hot  spring 

2N 

26E 

11 

n> 

Bodie  (15') 

? 

USGS  Bodle  15'  quad. 

No  otJier  reference 

11 

Getty  Oil  Co.  "State 
P. B.C.  4572. 1" 

2N 

26E 

23 

MD 

Bodie  115') 

136 

2437 

1971 

CDOG  Sum.  Op.  v.  57  no.  2 

1971 

13 

135 

2440 

1971 

CDOG  TR  13 

1975 

48 

56 

Also  see  p.  35 

12 

Mono  Basin  warm 
Spring 

2N 

2BE 

n 

M) 

Trench  Canyon 
(15') 

90 

USGS  S'.f.  492 

196S 

23 

121 

80-90 

USGS  WSP  338 

1915 

145-146 

Mono  8 

warm  spring 

91 

CDOG  TR  13 

1975 

48 

54 

WEED   SHEET 


1      B09U8   Soda   Spring*  47N        5W 


«J       Copco    (15') 


USGS   P.r.    A9? 


USGS  WSP    338 


E««  Appsndlx  D  for  location. 


Siskiyou 


Carbonated  aprlnqs 


1985 

WEED   SHEET 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


117 


APPENDIX   B   -    TABULATED   LIST   OF    THERMAL   SPRINGS    AND  WELLS 


MAP 
UX". 

NO. 

NAME 

LOCATICW 

QUADRANGLE 

WATER 
TEMP. 
CF) 

TOTAL 
DEPTH 
(FEET) 

YEAR 
DRILLED 

HEVEVLUCKiS) 

NOTES 

T 

R 

SEC. 

B&M 

PUBLICATION 

YEAR 

PACE 

LOC. 
NO. 

1 

Boqus   Soda   Springs 

47N 

5W 

13 

W 

Copco   (15-) 

72-76 

CDMG  Bull.    ISl 

1949 

56 

Klamath   Hot   Springs 

4eN 

3W 

27 

w 

MBcdoel    tlSM 

100-152 

uses   P.P.    492 

1965 

20 

2 

(Shovel  Creek 
Springs) 

112-156 

USGS  WSP   338 

1915 

120-121 

Siskiyou 

7 

(Besvlck  Hot  Sprlnqs) 

152 

OJMG  Bull.    151 

1949 

55 

3 

Sulphur  Springs 

15N 

8E 

29 

re 

Ukonom  US') 

90 

USGS  P.P.   492 

1965 

20 

1 

84 

USGS  Water  Res.   Dlv.   Open   File 
(No.   Coast  «   Klamath   Mtjis. ) 

1968 

28 

4 

Hot   spring  on   Ht. 
Shasta 

4  IN 

3W 

9 

H) 

Shasta   (15-) 

184 

Zeltschrlft  fxlr  Vullcanaloqte 

1934 

228 

" 

USGS  WSP   338 

1915 

144 

Siskiyou 
14 

•  See  Appendix  D  for   location. 


REFERENCES  CITED  IN  APPENDIX  B 


ABBREVIATION 


COMPLETE  REFERENCE 


CDMG  B  151 

CDMG  SR  75 

CDMG  SR  94 

CDMG  MIS  V.  17,  no.  11 

CDMG  MIS  V.  21,  no.  4 

CDOG    Huntington    Beach    Mop 
No.  134 

CDOG  Mop  G  5-1 

CDOG  Mop  G  6-1 

CDOG  Geotherm.  Hotline 

CDOG  Sum.  Op.  v.  57,  no.  2 

CDOG  TR  13 

CDOG  TR  15 

CDOG  written  comm. 
CDWR  Bull.  91-9 

CDWR  Bull.  91  17 

CDWR  Bull.  106-2 


Williams,  Howel,  1949,  Geology  of  the  Macdoel  quadrangle:  California  Division  of  Mines  and  Geology  Bulletin  151,  78 
P- 

McNitt,  J.R.,  1963,  Exploration  and  development  of  geothermol  power  in  California:  California  Division  of  Mines  and 
Geology  Special  Report  75,  45  p. 

Proctor,  R.J.,  1968,  Geology  of  the  Desert  Hot  Springs-upper  Coachella  Valley  area,  California:  California  Division  of  Mines 
and  Geology  Special  Report  94,  50  p. 

California  Division  of  Mines  and  Geology,  1964,  The  history  trail   (Dirty  Socks  spring):  Mineral  Information  Service,  v. 
17,  no.  11,  p.  202. 

California  Division  of  Mines  and  Geology,  1968,  Point  Arena  hot  springs:  Mineral  Information  Service,  v.  21,  no.  4,  p. 
61. 

California  Division  of  Oil  and  Gas,  1971,  Huntington  Beach  Oil  and  Gas  Fields  Mop  No.  134. 

Colifornia  Division  of  Oil  and  Gas,  1967,  Geothermol  Mop  Caso  Diablo  area.  Mop  G  5-1. 

California  Division  of  Oil  and  Gas,  1974,  Mop  of  The  Geysers    geothermol  area:  Map  G  6-1. 

Colifornio  Division  of  Oil  and  Gas  Geothermol  Hotline,  November  1972  and  December  1972  issues. 

California  Division  of  Oil  and  Gos,  1971,  Resume  of  oil,  gas,  and  geothermol  field  operations  in  1971:  California  Division 
of  Oil  and  Gos  Summary  of  Operotions,  v.  57,  no.  2,  p.   13. 

Hannah,  J.L.,  1975,  The  potential  of  low  temperature  geothermol  resources  in  northern  Colifornio:  Colifornio  Division  of 
Oil  ond  Gos,  Report  No.  TR  13,  53  p. 

Reed,  M.J.,  1975,  Chemistry  of  thermol  woter  in  selected  geothermol  oreos  of  Colifornio:  California  Division  of  Oil  and 
Gos,  Report  No.  TR  15,  31  p. 

Reed,  M.J.   (and  Don  Lande),  Colifornio  Division  of  Oil  and  Gos  written  communication  received  7/26/74. 

California  Department  Water  Resources,  1963,  Data  on  water  wells  in  Indian  Wells  Volley  oreo,  Inyo,  Kern,  and  Son 
Bernardino  counties,  California:  Bulletin  No.  91-9,  243  p. 

California  Deportment  Water  Resources,   1969,  Water  wells  and  springs  in  Ponaminf,  Searles,  and  Knob  Valleys,  Son 
Bernardino  and  Inyo  counties,  Colifornio:  Bulletin  No.  91-17,  109  p. 

California  Department  Water  Resources,  1967,  Ground  water  occurrence  and  quality.  Son  Diego  region:  Bulletin  No.  106-2, 
235  p. 


118 


DIVISION  OF  MINES  AND  GEOLOGY 


BULL.  201 


ABBREVIATION 


COMPLETE  REFERENCE 


CDWR  Bull.  143-7 

CDWR  Long  Valley  Invest. 

CDWR  Mom.  Bosin  Rept. 
CDWR-UCR  Dunes  Rept. 

OMG  V.  41,  no.  3 

Comegie  Inst.  Wosh.  Pub.  360 

Koenig,  1968 

Rex,  unpub. 

uses  GO  437 


USGS  Geoth.  Modoc  Co.    [open 
file) 

USGS  MF  577 


USGS  Open  File   (Imperial  Vo.) 

USGS  PP  385 

USGS  PP  440-F 

USGS  PP  457 

USGS  PP  486-G 

USGS  PP  492 


USGS  Woter  Res.  Div.  Open  File 
(Colo.  Desert) 

USGS  Water  Res.  Div.  Open  File 
(No.  Coast  &  Klamath  Mtns.) 

USGS  Water  Res.  Div.  Open  File 
(So.  Coast  -   Penin.  Ranges) 

USGS  WRI  13-73 


USGS  WRI  33-73 

USGS  WSP  142 

USGS  WSP  338 
USGS  WSP  1548 

Werner,  unpub. 

Zeitschrift  fiir  Vulkonologie 


California  Deportment  Water  Resources,  1970,  Geothermcl  wostes  and  the  water  resources  of  the  Salton  Sea  area:  Bulletin 
No.  143-7,  123  p. 

California  Department  Water  Resources,  1967,  Investigation  of  geothermol  v»aters  in  the  Long  Valley  area,  Mono  County, 
141  p. 

California  Department  Water  Resources,  1973,  Mammoth  basin  woter  resources  environmentol  study.  Final  Report,  70  p. 

Coplen,  T.B.,  and  others,  1973,  Preliminary  findings  of  on  investigation  of  the  Dunes  thermal  onomoly.  Imperial  Valley, 
California:  California  Department  of  Water  Resources  ond  University  of  California,  Riverside,  48  p. 

Tucker,  W.B.,  and  Sampson,  R.J.,  1945,  Mineral  Resources  of  Riverside  County:  California  Division  of  Mines,  California 
Journal  of  Mines  and  Geology,  v.  41,  no.  3,   (p.  178,  Highland  Springs). 

Day,  A.L.,  and  Allen,  E.T.,  1925,  The  volcanic  activity  and  hot  springs  of  Lassen  Peak:  The  Carnegie  Institute  of  Washington, 
Publication  360,  190  p. 

Koenig,  J.B.,  1968,  Field  trip  guide  to  The  Geysers,  Sonoma  County,  California:  Northern  California  Geological  Society 
Field  Trip  Guide. 

Rex,  R.W.   (Republic  Geothermmol,  Inc.,  Whittier,  CA) ,  Computer  print-out  list  of  data  on  geothermol  wells  in  Imperial 
and  Coachello  Valleys,  1972. 

Huber,   N.K.,  and  Rinehort,   CD.,   1965,    Geologic  map  of  the  Devils  Postpile  quadrangle.    Sierra  Nevoda,    California: 
U.S.  Geological  Survey  Geologic  Quadrangle  Map  GQ-437. 

Duffield,  W.A.,  and  Fournier,  R.O.,  1974,  Reconniossonce  study  of  the  geothermol  resources  of  Modoc  County,  California, 
U.S.  Geological  Survey  Open-File  Report,  19  p. 

Clark,  J.C,  and  others,  1974,  Preliminary  geologic  map  of  the  Monterey  and  Seaside  7V2'  quadrangles,  Monterey  County, 
California  with  emphasis  on  active  faults;  U.S.  Geological  Survey  Miscellaneous  Field  Studies  Map  MF  577. 

Hordt,  W.F.,  and  French,  J. J.,   1976,  Selected  data  on  water  wells,  geothermol  wells,  and  oil  tests  in  Imperial  Valley, 
California:  U.S.  Geological  Survey  Open-File  Report,  251   p. 

Rinehort,  CD.,  and  Ross,  D.C,  1964,  Geology  and  mineral  deposits  of  the  Mount  Morrison  quadrangle,  Sierra  Nevada, 
California:  U.S.  Geological  Survey  Professional  Paper  385,  106  p. 

White,  D.E.,  Hem,  J.D.,  ond  Waring,  G.A.,  1963,  Chemical  composition  of  subsurfoce  waters.  Chapter  F,  in  Doto  of 
geochemistry:  U.S.  Geological  Survey  Professional  Paper  440-F,  67  p. 

Smith,  G.I.,   1964,  Geology  and  volcanic  petrology  of  the  Lovo  Mountoins,  Son  Bernardino  County,  California:  U.S. 
Geological  Survey  Professional  Paper  457,  97  p. 

Metzger,  D.G.,  Loeltz,  O.J.,  and  Irelan,  B.,  1973,  Geohydrology  of  the  Porker-Blythe-Cibolo  area,  Arizona  and  California: 
U.S.  Geological  Survey  Professional  Paper  486-G,  130  p. 

Waring,  G.A.,  1965,  Thermal  springs  of  the  United  States  and  other  countries  of  the  world — A  summary:  U.S.  Geological 
Survey  Professional  Paper  492,  383  p. 

Berkstresser,  C.F.,  Jr,  1969,  Data  for  springs  in  the  Colorado  Desert  area  of  California:  U.S.  Geological  Survey  Open-File 
Report,  13  p. 

Berkstresser,  C.F.,  Jr.,  1968,  Data  for  springs  in  the  northern  Coast  Ranges  and  Klamath  Mountains  of  California:  U.  S. 
Geological  Survey  Open-File  Report,  49  p. 

Berkstresser,  C.F.,  Jr.,  1968,    Data  for  springs  in  the  southern  Coast,    Transverse,    ond  Peninsular  Ronges  of  California; 
U.S.  Geological  Survey  Open-File  Report,  21  p. 

Foye,  RE.,  1973,  Ground-woter  hydrology  of  northern  Napa  Valley,  California:  U.S.  Geological  Survey  Water-Resources 
Investigations,  13-73,  64  p. 

Moyle,  W.R.,  Jr.,  1974,  Temperature  and  chemical  data  for  selected  thermal  wells  and  springs  in  southeastern  California; 
U.S.  Geological  Survey  Water-Resources  Investigations  33-73,  12  p. 

Mendenhall,  W.C,  1905,  The  hydrology  of  Son  Bernardino  Valley,  California:  U.S.  Geological  Survey  Woter-Supply  and 
Irrigation  Paper  No.   142,  124  p. 

Waring,  G.A.,  1915,  Springs  of  Colifornio:  U.S.  Geologicol  Survey  Woter-Supply  Paper  338,  410  p. 

Cordwell,  G.T.,  1965,  Geology  ond  ground  water  in  Russian  River  Valley  areas  ond  in  Round,  Loytonville,  and  Little  Lake 
Valleys,  Sonoma  and  Mendocino  counties,  California:  U.S.  Geologicol  Survey  Water-Supply  Paper  1548,   154  p. 

Werner,  S.L.   (California  Department  Woter  Resources),  List  of  data  on  geothermol  wells  in  Imperial  Valley  (from  talk, 
1974). 

Willioms,  Howel,  1934,  Mount  Shasta,  California;  Zeitschrift  fur  Vulkonologie,  vol.  15,  pp.  225-253. 


1985 


TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


119 


APPENDIX  C 

INDEX  TO  THE  GEOLOGIC  FORMATIONS  GROUPED 

WITHIN  EACH  UNIT  PORTRAYED  ON  THE  GEOLOGIC 

MAP  OF  CALIFORNIA,  1977  EDITION 


Obviously,  all  the  individual  formations  mapped  in  California, 
of  which  there  are  well  over  1,000,  could  not  be  depicted  on  the 
1 :750,000  scale  Geologic  Map  of  California.  As  explained  in  Part 
II  of  this  bulletin,  the  units  portrayed  on  the  Geologic  Map  are 
drawn  on  the  basis  of  formation  boundaries,  but  there  are  nu- 
merous formations  contained  within  many  of  the  mapped  units. 
These  formations  are  not  portrayed  on  the  map  or  named  in  the 
geologic  legend — only  a  description  of  the  predominant  litholog- 
ic  types  for  each  mapped  unit  is  given  there.  For  a  complete  and 
detailed  listing  of  the  individual  formational  units  in  California, 
along  with  cross  indexes  by  geologic  age  and  by  map  sheet  areas, 
the  reader  is  referred  to  the  "Geologic  Legend  and  Formation 
Indexes"  which  accompany  the  Geologic  Atlas  of  California. 
The  index  of  geologic  formations  presented  in  the  following 
pages  is  much  more  generalized  than  that  of  the  Atlas;  it  was 
designed  not  to  supplant  the  Atlas  index,  but  rather  to  provide 
an  easy-to-use  listing  that  is  referenced  directly  to  the  units 
portrayed  on  the  1:750,000  Geologic  Map  of  California. 

EXPLANATION 

In  preparation  of  the  1 :75O,0OO  scale  Geologic  Map  of  Califor- 
nia, the  mapped  formations  in  the  state  were  grouped  into  52 
units  according  to  lithologic  similarities  and  rock  origins,  and 
were  also  arranged  chronologically,  according  to  relative  age. 
The  contacts  for  the  units  shown  on  the  1977  map  are  therefore 
based  on  actual  formation  contacts — if  not  individual  formations 
—then  grouped  formations.  The  following  list  shows  what  for- 
mations were  grouped  into  each  map  unit  shown  by  the  different 
symbols  on  the  1:750,000  scale  map.  This,  of  course,  is  a  state- 
wide synthesis,  and  in  any  one  location  either  a  single  formation 
is  represented  or  two  or  more  formations  have  been  grouped. 
Because  geologic  formations  commonly  transcend  time  bounda- 
ries, many  formations  listed  on  the  following  table  do  not  strictly 
fit  the  time  interval  indicated.  It  was  not  only  more  practical  but 
also  more  meaningful  in  compiling  the  map  to  conform  to  forma- 
tion boundaries,  which  can  be  more  easily  related  to  the  rocks 
in  the  field,  than  to  try  and  "take  apart"  the  geologist's  forma- 
tion and  draw  "time"  lines. 


Many  formations  in  the  following  list  are  described  in  paren- 
theses as  "(in  part)."  This  was  done  where  a  formation  is  com- 
pKjsed  of  rocks  of  vastly  different  lithologies  or  dissimilar  origin. 
For  example,  a  sedimentary  formational  unit  may  have  volcanic 
members  within  it.  In  such  a  case,  the  volcanic  members  would 
be  grouped  with  the  volcanic  units  (of  comparable  age  as  the 
sedimentary  unit).  Likewise,  a  marine  formational  unit  may 
have  interbedded  nonmarine  members,  and  these  would  in  most 
cases  (if  extensive  enough  to  show)  be  grouped  with  the  nonma- 
rine map  unit  of  appropriate  age. 

Most  of  the  designated  units  on  the  1977  map  contain  the 
formational  units  depicted  on  the  State  Geologic  Atlas  sheets; 
however,  where  subsequent  work  has  shown  that  certain  forma- 
tions were  of  a  significantly  different  age  than  what  was  previ- 
ously considered  (probably  as  a  result  of  the  discovery  of  new 
or  more-diagnostic  fossils,  or  by  reason  of  more  accurate  strati- 
graphic  correlations),  the  results  of  this  new  information  were 
taken  into  consideration,  and  the  formation  was  depicted  in  the 
most  appropriate  way  on  the  new  State  Geologic  Map. 

Several  new  geologic  units  are  shown  on  the  1977  map  that 
were  not  recognized  on  the  State  Geologic  Atlas.  These  include 
several  areas  in  the  southeastern  part  of  the  state  where  Tertiary 
granitic  rocks  have  been  dated  (gr*^  );  an  extensive  belt  of  Terti- 
ary-Cretaceous rocks  in  the  northern  Coast  Ranges,  known  as 
the  Coastal  Belt  rocks  or  "Coastal  Belt  Franciscan"  (TK);  two 
locations  of  newly  recognized  Paleozoic  (or  Permo-Triassic) 
granitic  rocks  (gr*^) ,  one  location  in  northern  California  and  one 
in  the  southern  part  of  the  state;  and  two  subdivisions  within  the 
Franciscan  Complex — a  melange  unit  (KJf„)  and  a  schist  unit 
(KJf.). 

If  the  reader  would  like  a  more  detailed  description  of  the 
individual  formational  units  listed  in  the  following  table,  he  may 
refer  to  the  various  stratigraphic  nomenclature  sheets  that  ac- 
company the  individual  Geologic  Atlas  sheets  or  to  the  source 
data  from  which  the  Geologic  Atlas  was  derived,  as  indicated  on 
the  explanatory  data  accompanying  each  sheet. 

For  a  more  detailed  explanation  of  the  way  in  which  the  rock 
units  were  classified,  and  for  a  discussion  of  special  stratigraphic 
problems  encountered  in  preparing  the  1:750,000  State  Geologic 
Map,  one  should  refer  to  pages  58-  63  in  Section  II. 


120 


DIVISION  OF  MINES  AND  GEOLOGY 


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TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


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TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA 


125 


APPENDIX  D 


I 


SOURCE  DATA  INDEX 


Following  the  format  of  earlier  Division  of  Mines  and  Geol- 
ogy indexes  to  published  geologic  maps  and  indexes  to  theses 
(see  below),  this  index  is  organized  by  State  Geologic  Atlas 
sheets  (generally  1°  x  2°  quadrangles).  In  determining  the  refer- 
ences used  for  any  particular  area  on  the  Geologic  Map  of  Cali- 
fornia, or  the  basis  on  which  a  fault  was  classified  on  the  Fault 
Map  of  California,  the  map-user  must  first  determine  the  State 
Atlas  sheet  on  which  his  area  of  interest  lies.  If  not  particularly 
familiar  with  these  sheets,  the  map-user  should  refer  to  the  State 
Index  Map  (Figure  16),  which  shows  the  boundaries  of  the 
individual  Atlas  sheets.  Once  the  map-user  knows  the  appropri- 
ate Atlas  sheet,  he  can  use  the  index  map  and  bibliography  for 
that  sheet  to  determine  the  source  data  used. 


HOW  TO  USE  THIS  INDEX 

This  index  should  be  used  in  conjunction  with  the  "Index  to 
Geologic  Mapping"  accompanying  each  sheet  of  the  Geologic 
Atlas  of  California,  1:250,000  series.  It  supplements  the  source 
data  given  in  the  Atlas  sheet  indexes;  only  references  that  were 
published  or  acquired  subsequent  to  the  issuance  of  the  corre- 
sponding State  Geologic  Atlas  sheet,  as  well  as  additional  refer- 
ences that  were  used  in  classifying  faults,  are  shown  in  Appendix 
D.  Some  of  these  references  were  received  late,  and  may  not  have 
been  used  (or  were  used  only  in  part)  in  the  compilation  of  the 
Fault  Map  of  California  and  the  Geologic  Map  of  California. 
They  are  included  here  because  of  their  potential  usefulness  to 
persons  seeking  more  recent  references  for  an  area.  * 

Because  the  primary  purpose  of  the  Fault  Map  of  California 
is  to  provide  more  information  on  individual  faults,  especially  for 
active  or  potentially  active  ones,  particular  attention  has  been 
given  to  providing  references  to  the  historic  and  Quaternary 
faults.  For  ease  in  locating  references  on  specific  historic  or 
Quaternary  faults,  the  index  maps  have  selectively  shown  these 
faults,  albeit  in  a  generalized  and  simplified  form  (using  solid 
and  dotted  lines  only).  For  more  accurate  depiction  of  these 
faults,  the  reader  should  refer  to  the  1:750,000  Fault  Map  of 
California.  If  no  source  data  are  given  for  a  specific  fault  shown 
on  the  index  sheets,  then  the  reference (s)  used  were  taken  from 
the  published  1:250,000  State  Geologic  Atlas  sheets,  and  the 
reader  should  consult  the  Atlas  and  its  accompanying  source 
data  indexes. 


OTHER  REFERENCES 


For  more  extensive  references  to  areal  geologic  mapping,  the 
reader  is  referred  to  the  following  publications  of  the  California 
Division  of  Mines  and  Geology: 

Indexes  to  Published  Geologic  Maps 

Special  Report  52,  Index  to  Geologic  Maps  of  California  to 
December  31,  1956,  by  R.  G.  Strand,  J.  B.  Koenig,  and  C.  W. 
Jennings. 

Special  Report  52-A,  Index  to  Geologic  Maps  of  California, 
1957-1960,  by  J.  B.  Koenig. 

Special  Report  52-B,  Index  to  Geologic  Maps  of  California, 
1961-1964,  by  J.  B.  Koenig  and  E.  W.  Kiessling. 

Special  Report  102,  Index  to  Geologic  Maps  of  CaUfomia,  1965- 
1968,  by  E.  W.  Kiessling. 

Special  Report  130,  Index  to  Geologic  Maps  of  California,  1969- 
1975,  by  E.  W.  Kiessling  and  D.  H.  Peterson. 


Indexes  to  Theses 


Special  Report  74,  Index  to  Graduate  Theses  on  California  Geol- 
ogy to  December  31,  1961,  by  C.  W.  Jennings  and  R.  G. 
Strand. 

Special  Report  115,  Index  to  Graduate  Theses  and  Dissertations 
on  California  Geology,  1962  through  1972,  by  G.C.  Taylor. 

California  Geology,  February  1978,  Index  to  Graduate  Theses 
and  Dissertations  on  California  Geology,  1973  and  1974,  by 
D.H.  Peterson  and  G.J.  Saucedo. 

California  Geology,  April  1978,  Index  to  Graduate  Theses  and 
Dissertations  on  California  Geology,  1975  and  1976,  by  D.  H. 
Peterson  and  G.  J.  Saucedo. 


•Becaust  of  the  lale  publication  of  this  Bulletin  (more  than  ten  years  after  the  compilation  of  the  Fault  Map  of  California  and  the  Geologic  Map  of  California),  many  of 
the  references  cited  in  Appendix  D  as  ■"work  in  progress"  have  subsequently  been  published  Because  of  subsequent  changes  that  may  have  occurred  from  the  "work  in 
progress"  stage  to  the  final  published  work,  no  attempt  has  been  made  to  update  this  Source  Data  Index  with  later  references.  Hence  the  references  cited  in  Appendix  D 
are  largely  those  that  were  actually  used  in  the  compilation  of  the  Fault  and  Geologic  Maps  The  source  data  should  be  quite  complete  to  approximately  1972  In  a  few- 
instances  this  Source  Data  Index  contains  some  references  up  to  1975  that  were  added  after  the  Stale  maps  had  been  compiled  and  while  the  text  of  this  bulletin  was  being 
wntten 


126 


DIVISION  OF  MINES  AND  GEOLOGY 


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Figure  16.  Slote  index  mop  showing  the  boundories  of  the  individuol  Geologic  Alias  sheets  ond  the  source  doto  index  mops  in  Appendix  D. 


1985  TEXT  TO  ACCOMPANY  THE  FAULT  AND  GEOLOGIC  MAPS  OF  CALIFORNIA  127 


EXPLANATION  OF  MAPS 

On  the  following  index  maps  of  Appendix  D,  some  of  the 
boundary  lines  are  solid  and  some  are  dashed.  The  dashed 
boundaries  indicate  one  of  the  following: 


(a)  The  extent  to  which  a  source  map  was  used — that  is,  that 
the  source  map  continues  farther,  but  that  other  data 
were  used  beyond  the  dashed  boundary. 

(b)  The  area  enclosed  includes  only  selected  data,  for  exam- 
ple, fault  data  only. 

(c)  The  boundary  of  one  map,  where  two  or  more  maps 
overlap — in  the  interest  of  clarity  in  cases  of  overlapping 
source  data. 


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3  1 


INIVERSITV  OF  CALIFORNIA,  OAVII 


75  02103  8438 


COLLATE: 


PIECES 


STATE  OF  CALIFORNIA- GEC 
THE  RESOURCES  AGENCY  -  GORDON  K. 
DEPARTMENT  OF  CONSERVATIO! 


>v 


DIVISION  OF  MINES  AND  GEOLOGY 
JAMES  F  DAVIS.  STATE  GEOLOGIST 


STATE  OF  CALIFORN 

THE  RESOURCES  AGENCY  -  G( 

DEPARTMENT  OF  CON! 


MAP  A      Structural  Piofincei  of  Colilornlo  daletmined  by  the  prominent  foult  paltemt  and  ehorocteri»fi«  of  Hn  faulti  they 
tonioin  or  bound.  lEncitcled  numberi  in  lower  port  of  mop  identify  certain  foulti  referred  to  in  te»t.) 


RGE  DEUKMEJIAN,  GOVERNOR 

'AN  VLECK,  SECRETARY  FOR  RESOURCES 

I -DON  L  BLUBAUGH,  DIRECTOR 


Faull  ond  Geologic  Data  Mops  of  California 
BULLETIN  201.  PLATE  2 


MAP  B;     Parollelilm  between  major  Quoternory  faults  and  regularity  of  foolt  spacing.  ( Encirc^d  numbers 
in  lower  portion  of  mop  identify  certoin  faults  referred  to  in  the  text.) 


MAP  C:  Relotionship  of  eorthquoke  epicerXers  to  foulls  in  Colifornia,  Note  the  close  relationship  of 
eorthquokes  of  magnitude  6  ond  greoter  to  the  mojor  Quoternory  foults.  (Epicenters  from 
Eorthquoke  Epicenter  Mop  Of  Colifornio,  1900-1974,  by  C.R.  Real,  T.R.  Toppozodo  ond  O.L. 
Pofke,  1978-1 


OD 


n 


MAP  Dl  Earthquake  epicenters  of  magnitude  4  to  4.9  showing  more  scatter  than  for  the  lorger  earth- 
quakes, but  olio  suggesting  certain  oreos  of  low  historic  seismicity.  (Epicenters  from  Earthquake 
Epicenter  Mop  Of  Colifornio,  19001974,  by  C.R.  Real.  T,R,  Toppoiobo,  ond  DL.  Porke.  1978.) 


So 


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