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
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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.
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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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Figure 4. Map of California and adjacent terrane showing major Quaternary foults and identifying historic fault breaks, occurrences of fault creep, and trig-
gered creep.
20
DIVISION OF MINES AND GEOLOGY
BULL. 201
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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
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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.
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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.
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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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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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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.
1985
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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
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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
BULL. 201
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1985
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
•
1
<
Z
K
1-
^
1
o
^
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
TEXT TO ACCOMPANY THE FAULT AND GEOLOGIC MAPS OF CALIFORNIA
69
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74
DIVISION OF MINES AND GEOLOGY
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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
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
BULL. 201
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.
128
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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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