Marine magnetic surveys in the northwest Pacific Ocean

TR-168

TECHNICAL REPORT

MARINE MAGNETIC SURVEYS
IN THE NORTHWEST PACIFIC OCEAN

DEWEY R. BRACEY

Geomagnetics Branch
Marine Surveys Division

SEPTEMBER 1963

U. S. NAVAL OCEANOGRAPHIC OFFICE
ft. TR -/UF WASHINGTON, D. C. 20390
Price 25 cents

ABSTRACT

A geomagnetic and bathymetric survey of two adjacent areas
off the east coast of the Kamchatka Peninsula has shown
steep, high amplitude magnetic anomalies occurring on or
near the edge of the continental shelf.

FOREWORD

The geophysical data presented in this report were collected in

an area of complex crustal features. Measurements of this type pro-

vide basic information for further interpretation of the structural

character of oceanic areas.

DENYS W OLL
Rear Admiral, U. S. Navy
Commander

Women TAH

alatat

II.

CONTENTS

ION ORLOWDIOKGAON 5 9 96 0 GO 6 6 0 8 68 8 68 Oo 0 Go 1

SURVEY OPERATIONS

A. Comcnee oF Survey oo 6 5 50 65056 0 5 0 Oo Oo il
1B, IMSEewMMMEELOM 6 o 56 6 00500600560 00 6 2
DAIWA ROGOSSIING 6 5 5 50 0 0000000000000 2
SUAVE IBSUIENS 6 6 56 6 6 5 0 0 00008 OO 8 3

SUMAN OL TIONS 56 56 6 6 60005000 60 6 0 4
FIGURES
North Pacific Survey - 1962 Areas "A" and ''B"

Loeaiilon GMa o 6 6 6 0000 ol Ol 5

North Pacific Survey - 1962 Area "A" Survey Track
Cfolcar CRM sila tere Marsch eD en Lwotyten yo" teri tome sit acoiipiey a tolarte le Neniney bey liey we 6

North Pacific Survey - 1962 Area ''B'' Survey Track
(ies aes Tgehootumecs Oo AtoO lo-stOn Ohio VO Os Cec nO Ono ED mLON DEG 7

North Pacific Survey - 1962 Area "A'' Total Magnetic
ihneemeiliey Comzous Cnewie 56 5656000500000 000 8

North Pacific Survey - 1962 Area ''A" Bathymetric
Comrour Oneree 56 6600 0600005 05019 5 6 6 6 9

North Pacific Survey - 1962 Area '"'B" Total Magnetic
imeeasiliey Gomeoure Goevete 56 56050000000 0000 LW

North Pacific Survey - 1962 Area ''B'" Bathymetric
Gomieouie Gneete 4 50 6 00 0 6 0'6 6 046656 6 0 6 oO Ail

ca slaogeia: "

* # . » ie +
f -

nicvenyeM faxed

eiyeel
he

TN Oe

-

"ts ie ¥ ;

Othe BOR Is at vay Luda) Ta
y " pe" iets

ea tht Sotto

77 f rz +)
Te! AA Ee ae Se ERE:

I. INTRODUCTION

A survey of two adjacent areas east of the Kamchatka Peninsula
was conducted by USS REHOBOTH (AGS-50) between June and September
1962. Location of the survey areas is shown in figure 1.

The survey of these areas was part of NAVOCEANO Project 0-162,
a general investigation of geomagnetic, oceanographic, and bathy-
metric properties in the North Pacific Ocean. The geomagnetics
phase of this survey was conducted as part of an overall geophysi-
cal program to improve accuracy of magnetic data on charts, and
to provide information on underlying oceanic crustal features.

Although this report deals primarily with the results of the
geomagnetic investigations, bathymetric data are included for
correlation with the magnetic data and to aid in geologic

interpretations.

II. SURVEY OPERATIONS

A. Conduct of Survey.

Tracks in survey area "A" (figure 2) were generally run in
an east-west direction normal to the coast of the Kamchatka
Peninsula. Line spacing is approximately 7 miles in the southern
part of the area, and approximately 20 miles in the northern part.
Area coverage is most complete in the center of the area.

In survey area "B" (figure 3), tracks are generally oriented

in a northwest=southeast direction with a line spacing of about

5 miles. Average ship's speed in the two survey areas was 12
knots.

Control in the survey areas was maintained when possible by radar
and visual fixes obtained at one hour time intervals. Fix accuracy
during these periods is estimated as being approximately one mile.
When out of visual and radar range of land, position was maintained by
celestial navigation and dead reckoning. Fix accuracy is reduced
during these periods to an estimated + 5 miles.

B. Instrumentation.

Total magnetic intensity measurements were made with a Varian
marine proton precession magnetometer, model V-4931. The sensor unit
for this magnetometer was contained in a cylinder 24 inches long and
6 inches in diameter. This sensor was towed 5/5 feet astern in order
to reduce the effect of the ship's magnetic field.

Because of equipment design, magnetic data were recorded as
"magnetometer counts,'' a unit of measurement inversely related to the
magnetic field intensity. These units were recorded on a Varian model
G-11A analog recorder and printed out in digital form on a Hewlett-
Packard digital recorder, model 560-A.

Bathymetric data were obtained with a Precision Depth Recorder

(MK-V) and an AN/UQN 1-D sonar sounding set.
ITIL. DATA PROCESSING

The magnetic data from the analog tapes were scaled and converted
from magnetometer counts to absolute values in gammas (1 gamma =
1 x 10-5 oersted) by the use of a template. These data were used to
construct magnetic total intensity contour charts on Mercator Pro-

jections at a contour interval of 50 gammas (figures 4 and 6).

Bathymetric contour charts were constructed on the same projection
using a contour interval of 100 fathoms (figures 5 and 7).

No corrections were made to any of the magnetic data for
temporal variations of the earth's magnetic field.

Because geomagnetic and bathymetric data were collected simul-
taneously in the two survey areas, bathymetric and magnetic charts
may be used for direct comparison of the data. No sound velocity or

other corrections have been made to the bathymetric data.
IV. SURVEY RESULTS

Survey areas "A" and "'B" (figure 1) have a total combined area
of 32,500 square nautical miles. The larger area, "A'', lying east
of the Kamchatka Peninsula, contains 25,900 square nautical miles. The
smaller area, ''B', adjoining the southwest corner of "'A'', contains
6,600 square nautical miles.

The area "A" total magnetic intensity contour chart (figure 4)
shows broad magnetic anomalies associated with the bathymetric
features (figure 5) east of an imaginary diagonal line drawn from
latitute 53°N.; longitude 160°10'E. to latitude 56°N.; longitude
163°30'E. West of this line the anomalies become very steep with
relatively high amplitudes. These anomalies occur on or near the
edge of the continental shelf where the slope drops sharply down to
1500-2000 fathoms. The steep anomalies end abruptly south of Cape

Kroznotzky then reappear to the north of the cape.

7)

azaaaart ds a ds iw he jebtonns abd boTwee

e

sive: vata an). den vat vaxhgeaey mike 10 4anu

va abut ai st : Wy

porte et. 7) oe ha
oa To at

aay sd ail weede SP OnE!

WR ty 2 Video Berd
yan > t
[ 3 if , £ eas 4 ]d.1 4408s § “pe ey has 3 —-
SS
>, ; an r by
meek y lay ab Sanka arto amiele Trike 4
3 , ; ( (AS i aot eee Crea St
d pS 4 iv
‘ Pe 5 = Be i SA 3: =i

fo

*

dae

oa E

ats a" 7 >

be Sa

Tt
La esi
|

The area "B'" total magnetic intensity contour chart (figure 6)
shows another high amplitude magnetic anomaly. This anomaly is also
located at the edge of the continental shelf (figure 7), and west of
the southeastward extension of the line mentioned in area "A." A
magnetic anomaly on the extreme eastern edge of area "'B'' corresponds
very closely to a small bathymetric trough at the same location.

V. SUMMARY OF FINDINGS

This survey has shown the presence of steep, high amplitude
Magnetic anomalies near the edge of the continental shelf off the
east coast of Kamchatka. These high amplitude anomalies end abruptly
south of Cape Kroznotzky then reappear to the north of the Cape.

West of the continental shelf, over the deeper ocean basin, the
magnetic anomalies broaden. These broad anomalies seem to be associ-

ated with the bottom topographic features.

LYVHD NOILVYDO7T ..€,, GNV ..W,, SVAYV Z96I—-AZAUNS DIAIDVd HLYON—'| JYNDIS

1epuas |. o>?
TEEROH uesuom9?
NVdvVf dO Vas
ueusupA

JNM Jiva

bjevepoyeH

“ Ad
oy PO}SOA:! Y
rqeoun§, 7 : jOYSOAIPE ‘
mpsoig Nsjaqwioy, a >
yi ujd-yse-eH o
nddniy Vd :

naryenangs »

inte a ysaoieqeyy.d!..
. X,
weIoyeUIQ7 = YWIHSTHO eee et
anaes § ysueyousenodeig

nha. we YvV; eyiedoy shy

4,

S “pe of 8] jouvarpuy

“I "11 roarey yoyng
} 4

eumray) ; Lo

odtysropuemid
BA0II8Q)

Cowsnane]oyiN

y HMO JO VaS

4
©
el SGU S&S ' M V S| dq V

fo

. “ % 0!
i 2 fi Da0y7a124S, ae

<7 yeayan Ny Sxoupiey ag 7 5 HE ‘ © AGW PT

“ueyyeAen

ueyowAss o

QouaIMey a 7 C9 WwW

ie

oy

[160°

161° 162° 163°

56° -—

55°

aes
ama

POLUOSTROV

KAMCHATKA

cy tad cy
54° }—
\ 20 JUN 62 Va MERCATOR PROJECTION
y ie / ALL TIMES GMT
———— /
400 Soe 4m 82/
————— i7as
53° 4 oon SI |
160° 161° 162° 163° 164°

53°

FIGURE 2.—NORTH PACIFIC SURVEY -1962 AREA ‘A’? SURVEY TRACK CHART

LYVHD WOVAL AZAUNS ..€,, VAUV 296I- AAAUNS DISIDVd HLYON—'€ FYNSIA

ol ST o09T

T ee |

LWS SAWIL 11V
NOILD3fOUd YOLVIYAW

t9 1438 0
OO

J es

—
160° 161° 162° 163° 164°
56° T ise
POLUOSTROV
KAMCHATKA
55° _I 55°
54° = 54°
- MERCATOR PROJECTION
$ CONTOUR INTERVAL SO GAMMAS
53° so) | Z ! | 53°
160° 161° 162° 163° 164°

FIGURE 4.—NORTH PACIFIC SURVEY-1962 AREA ‘‘A’’ TOTAL MAGNETIC INTENSITY CONTOUR CHART

4

ii
et

;

POLUOSTROV

KAMCHATKA

fir)
161°

—

FIGURE 5.—NORTH PACIFIC SURVEY -1962 AREA‘‘A’’ BATHYMETRIC CO

NTOUR CHART

|
LYVHD YNOLNOD ALISNALNI DILANOVW WLOL ..d., VANV 2961l- AZAUNS DIAIDVd HLYON—'9 JFYNDIS

EAS)

SVWWYVS OS TIVAYALNI YNOLNOD
NOILD3fOUd YOLVIYAW

10

,0€

o€S

LYVHD YNOLNOD DIYLAWAHLVE ..d,, VAYV C9G6I-AAZAYUNS DIsIDVd HLYON—'Z AYNDIS

ol 9T o09T

o6ST

ErAc]

| le

SWOHLV4 OO! IVAYNSLNI YNOLNOD

o€S

NOILD3fOUd YOLVDYAW

RAS)

ofS

ses pai nes me eh ha

ca lr ire en aR eg

“ABHA S001 YAVAUS QITIOAG HTAOK—X BauOT

r

89T-aa

Avoeig

*y Aomoq :i0yRny
Nvad00 O1d10vd
LSAMHLYON FHL NI
SAGAYNS OLLYNDVN
GNTAUVN + eTtEL

ws TJouseyW--ues00
DTFPIeG Jsemy AON

ues0Q ITFPOR
}SOMu}ION--TeTIAI
-Solioy ‘ust jousey

le
|

S9OT-aL

Avoeig

*y Aemeq :ioy ny

Nva00 Old1ovd
ISAMALYON HL NI
SATAUNS OLLINOVW

ENTYVA + 913FL

Ws TJ ouse_W--uUesI0
DFFPIOeG Jsemy soy

uvs0Q9 ITFPOeg
JSOMYIION--TeTIF
-Soltoy, ‘ust Jousey

LL

1-

“TEE

“TF

‘e[Nsupueg ey eyouey
eu} FJFJO F[eys [equouyzjuos. s9yQ
AIgeu 10 Uo BUTAAINDIO set [euoue
dFJeusew epnzzT{dwe y3ty ‘deeqs
uMOYs APY IFJPOeG Jsemy.aou

ey} uz shovAINS OF}OUseWOay
°Z «(89T-UL) “Sean3yzz / Buzpnpouy sd TT
"€961 Aequeqdes ‘Av0eI1g *y Aomog
&q ‘NVH90 D1d1D0Vd LSAMHIMON FHL

NI SASAYNS OLLEYNOVN ANTYVN

89T-aL

Aooeig

°y Aemaq :10yuINy

NVH00 ODLALDVd
LSAMHLYON FHL NI
SAYAUNS OILANDSVN

GNTYVW + OTIEL

us FJ oUse_--ues00
DTFPIeG IZsemy json

ues00 IFF}FOe
JSeMyZION--[eTI3

mails 20FFIO WFYderasours|dg TePAeN “Ss ieee ‘us TJousey,

“FFT 89T-aL

Avorig

“TT *y Aemeq :104RNy
“e[Nsupueg eyIeyoMEy

243 JFO FLEYS [eJUSUTIJUOD 9yQ NVa00 OldloVvVa

iegou 10 uo 3UTiindd.0 seT[euoUe ISAHMHLYON AHL NI

DFZeusew spnzy{[dwe ysty ‘dees SAMAMNS DLLENOVW

cay: umoys oAeYy ITFp~oOeg IJSsemyjAou FNIMWA °° EL

ey. uz skoAins df}euseuUoey

Us TJ ouse_--Uesd0

°% (89T-UL) “seansytz /¢ Buzpntout *d T{T ozzToeg AsemyIIoN
“€96T Aequeqdas ‘hooeig *y Aomog

Aq ‘NVH90 O1d10Vd LSAMHINON FHL ues0Q ITF FOR

NI SAGAYNS DILANDVW ANIYVW JSOMYIION--TeFAW

“E 227550 WTYyderasouv|a209 TeAePN *§ “N -saztez ‘wsyTJoUseY

Me

“FFF

“TT

°G

‘e[Nsuyusg eyxIeyoury

243 JFO FLSYS [eRUSUTIJUOD aya

ieeu IO uo 8UTIINI.0 seT[ewoue

DFJeuseu spnzTTdwe ysty ‘deeqs

umoys sAeYy IEJ}ToOeg JsemyjaoU
247 Uz skaAIns dFeusewosy

(89T-UL) “Sean3zz / B3uzpnztout -d TT
“€961 Jequejdsas ‘kooei1g *y Komog
&q ‘NVH90 O1d10Vd LSAMHINON AHL

NI SAHAYOS OLLANOWN FNTUVW
20FFFO WDTYdezSouves9 TeAeN “Ss *Q

—]
7

‘e[Nnsujtueg eyIeyauey

ay. JJO F[SYUS TeJUSUTIUOD 943

Aegau IO UO BUTIINDDO saT[ewoue

dFJouseu opnzt{dwe ysty ‘dseqs

umoys oAeY ITJTIeg JSsemyjioU
oy} uz shvAins dTJaeuseuoey

(89T-UL) *“Seanszz { ZuFpnzpouy *d TT
°€Q96T Aequeqdsg ‘Kkooeig *y Aomeg
&q ‘NVH90 OLdlOVd LSAMHINON AHL

NI SAWAWOS DILANOVW YNIYVW
SIFFIFQ OFYdeABOUPZDO TeARPN °S “f
al

r

89T-UL

Avoeig

*y Aemeq :z204;nNy

NVd0O OLATOVd
LSAMHLYON SHI NI
SAGAUNS OLLYNDVN

GNTYVN + OTFEL

WS TJoUse_--ues0Q
DTFPOeG WsSeMy ION

uvs00 ITFFOeYg
JSOMyIION--TeTIA
-Solioy ‘ustjousey

Hes

S9OT-UL

Avorig

*y Aemeq :ioyqny

NVd90 OLALDVd
LTSAMHLYON FHL NI
SATAUNS DILINDVN

SNTYWN + 9TFFL

Us F}9USe_--uesIQ
OFF FIC JsSomy soy

ue9009 IFFTOeg
soemyqION--TeTI2
-Seijey, ‘ustzousey

ie

“FFF

“TT

>

‘e[Nsupueg eyIeyoury

ey} JJO FJ[eys Tequeutjuos ay q

ieou Jo uo B8uTiindd0 saeT[ewoue

dFJeusew spnzy{dwe ysty ‘dees

umoYys sAeY OFF POCA JSemMy.irou
ey. uz shoAins dTJeuseuoesy

(89T-UL) ‘“sean3zz /¢ Supzpnpouz -d [tT
“€961 tequejdag ‘Av0eI1g *y Aomog
4q ‘NVH90 O1d10Vd LSAMHINON FHL

NI SAGAYOS OLLANOVW ANIYVW
29TFFO WFYdeasSoursd9 TeAeN *S “pn

89T-UL

Aooeig

*y Aemeq :toyqny

NV400 OLALDVd
LSAMHLYON FHL NI
SATAUNS OLLANOVWW

SNTYVN + °TFEL

ws TJ ouseW--uevI0Q
OFJ}Ieg Jsemy.ioy

ue9090 ITFPoeg
ISaMYyIION--[eTI13
-Seitey, ‘ustjousey

a

“e[Nsupueg ey eyouey

243 JJO FLEYS TeJUeUT JUOD aya

desu 10 uo 3UTIAinds0 sot[ewoue

oFJousew epnzT{dwe y8ty ‘dseq4s

uMoYys sAeY ITJTOeg Isemyjaou
e247 uz skeains df eusewosy

(89T-YL) ‘“sean3}z /¢ Buzpntouy -d TT
"€961T Jequeqdeg ‘fka0e1g -y Aamog
&q ‘NVa00 OI1dI0Vd LSAMHINON FHL

NI SAHAYNS DILENOVW ANIUVN
PFIFO WFYdeasouvssg9 TeAeN °s “fp

IT

S9T-aL

Avoeig

*y Aemeq :10y ny

NVH00 DIAIDVd
DLSAMHLYON FHL NI
SAGAYNS OILENDVN

SNTYVN + PTFEL

us TJ oUse_--uers00
dTFPIeg IJsomy soy

ues0Q9 ITF }Foeg
JSOMYIION--TeTAA
-Soltey, ‘ust Jousep,

ML

“FFF

“TE

‘e[Nsupueg ey.eyouey

247 FFO FTSYsS Te UeuT IUOD sayy

ieeu 10 UO 3UTIIND50 soT[emoue

d}Jouzew apnzz{dwe y8ty ‘dseaqs

umoys vAey FJ}Oeg Jsemyjaou
2°47 UF sXkeAIns d]T}oUuseMO0aD

(891-YL) “sean8zz / Buzpnyouy *d TT
“€961 tequieqdag ‘Xkaoeig *y Aameg
4q ‘NVH00 O1dIOVd LSAMHLYON AHI

NI SASAUNS OILENDVN ANIYVW
2°9FFFO ITYderzSouescg TeAeN °s *Q

=)
5

‘e[Nsuyueg ey}eyauey

24} JFO FTEYS Te RUSUTIUOD 943

Iesu IO uo SUTIINDDO set[ewoue

DFJousew opnqtT{dwe y3ty ‘dsaaqs

umoys oAeYy IFJ}FOe™g Jsamy}iaou
ey} ut skaAIns oF ZouseUOaD

(89I-UL) ‘“SeanszzZ / Buzpnpouy *d TT
“€96LE tequierdag ‘ko0e1g *y Aomag
Aq ‘Nva90 OIdIOVd LSIMHLYON AHL

NI SAGAYNS DILENOVW ANIYVN
SdFFIFO OFYderasouesd,9 TeAeN *S ‘pA
=|