Crustal strain and fault movement investigation; progress report

TC

no. 116:/

;":ARY

THE RESOURCES AGENCY OF CALIFORNIA
partment of Wa ter Resources

BULLETIN No. 116-1

n

CRUSTAL STRAIN

AND FAULT MOVEMENT

INVESTIGATION

Progress Report

MAY 1963

HUGO FISHER

EDMUND G. BROWN

WILLIAM E. WARNE

Administrator

Governor

Director

The Resources Agency of California

State of California

Department of Water Resources

ACTIVE FAULTS

1

2
3

SAN ANDREAS
NACIMIENTO

HAYWARD -
CALAVERAS

II

12
13

MILL CREEK-
MISSION CREEK

IMPERIAL
SAN JACINTO

4

SANTA YNEZ

14

A6UA CALIENTE

5
6

BIG PINE

GARLOCK

15
16

ELSINORE
INGLEWOOD

7

WHITE WOLF

17

SAN CLEMENTE

8

SIERRA

18

MANIX

9

HELENDALE

19

FORT SAGE

NEWBERRY

20

MOHAWK VALLE

Active Earthquake Faults in California

state ot Calitornia
THE RESOURCES AGENCY Of CALIFORNIA

Department of Wa ter Resources

BULLETIN No. 116-1

CRUSTAL STRAIN

AND FAULT MOVEMENT

INVESTIGATION

Progress Report

MAY 1963

HUGO FISHER EDMUND G. BROWN WILLIAM E. WARNE

Administrator Governor Director

The Resources Agency of California State of California Department of Water Resources

LIBRARY
u*i».raii;iTY OF CALlFOHAiA

TABLE OF CONTENTS

Page

LETTER OP TRANSMITTAL v

ORGANIZATION vl

ACKNOWLEDGMENT vil

INTRODUCTION 1

CALIFORNIA EARTHQUAKES — A SPORADIC PROBLEM 3

REVIEW OP EARTHQUAKE INVESTIGATIONS IN CALIFORNIA 9

United States Coast and Geodetic Survey 12

California Institute of Technology 12

University of California at Berkeley 13

Stanford Research Institute 13

Other Universities and Public Agencies 13

Earthquake Engineering Research Institute 14

DEPARTMENT CRUSTAL STRAIN AND FAULT MOVEMENT INVESTIGATION . . 15

Scope and Objectives of Investigation 15

Program Accomplishments to Date l8

Fault and Earthquake Epicenter Map l8

Earthquake Hazard Evaluations 19

Electronic Data Processing 19

Technical Reports 20

Geodlmeter Survey 20

Trlangulatlon Survey 21

Federal-State Cooperative Subsidence Leveling

Program 22

Future Program 22

Applied Seismology Studies 23

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Geodetic Studies 30

Engineering Geology Studies 32

DEPARTMENT EARTHQUAKE ENGINEERING INVESTIGATIONS 35

Illustration No ,

Frontispiece

1

2

ILLUSTRATIONS

Active Earthquake Faults in California
San Andreas Fault, San Bernardino County
San Andreas Fault, San Luis Obispo County

Page

Plate No.

PLATES
(Plates bound at end of bulletin)

1 Crustal Strain and Fault Movement Investigation
Geodetic Program

-iv-

pn GOIDEERG
'jputy Director

lUD C. PRICE
iDireclor Policy

I' GARDNER

EDMUND G BROWN
GOVERNOR Of
CALIFORNIA

HUGO FISHER

ADMINISTRATOR

RESOURCES AGENCY

ADDRESS REPLY TO
P. O. Box 388
Socramenlo 2, Colif.

THE RESOURCES AGENCY OF CALIFORNIA

DEPARTMENT OF WATER RESOURCES

1120 N STREET, SACRAMENTO

February 27, I963

The Honorable Edmund G. Brown, Governor, and
Members of the Legislature of the
State of California

Gentlemen:

I have the honor to transmit herewith Bulletin No. II6-I,
"Crustal Strain and Fault Movement Investigation — Progress Report."
This Investigation was initiated by the department in 1959 under
funds budgeted for the California Water Development Program. Plans
are under way to implement additional Investigations into earthquake
problems and their solution based on recommendations of our Consult-
ing Board for Earthquake Analysis.

The major objectives of the department's earthquake engin-
eering investigations are: (l) to Investigate, evaluate, and report
on all phenomena of earthquakes, faults, and crustal movements which
may affect engineering planning, design, construction, operation, and
safety of hydraulic structures; and (2) to develop earthquake, crus-
tal movement, and aseismic design factors and criteria to improve or
replace the empirical factors in current use for the engineering
design of hydraulic structures in California,

Bulletin No. II6-I has been prepared primarily as a brief
report to the Legislature on the objectives, accomplishments, and
proposed future program of the Crustal Strain and Fault Movement
Investigation -- which may appropriately be referred to as the earth-
quake hazard studies of the department. This report also briefly
refers to the objectives of the programs now being formulated for the
department's other earthquake engineering investigations. This
report will provide background for a series of earthquake data and
earthquake engineering reports which will be issued by the department
as progress is made in these investigations.

Sincerely yours.

Director

i

STATE OP CALIFORNIA

THE RESOURCES AGENCY OP CALIFORNIA

DEPARTMENT OP WATER RESOURCES

EDMUND G. BROWN, Governor
HUGO PISHER, Administrator, The Resources Agency of California
WILLIAM E. WARNE, Director, Department of Water Resources
ALFRED R, GOLZE ' , Chief Engineer

DIVISION OP RESOURCES PLANNING

William L. Berry Division Engineer

Raymond C. Rlchter Geology Staff Specialist

The investigation leading to this
report was conducted under the direction

of

Meyer Kramsky* Chief, Statewide Investigations Branch

and
Carleton E. Plumb Chief, Planning Investigations Section

by

David M. Hill Senior Engineering Geologist

William M, Gibson Associate Engineer, Water Resources

Laurence B, James Chief Geologist and Coordinator of

Department's Seismic Investigations

*Albert J. Dolclnl was Chief of the Statewide Investigations Branch
until July 1, I962.

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ACKNOWLEDGMENT

Valuable assistance^ data, and consultation by federal,
state, and private agencies and Individuals have materially assisted
the department in its studies of seismic problems in California. In
particular, the continued cooperation and assistance of the following
individuals and agencies are acknowledged: Professors Hugo Benioff,
Charles Richter, George Housner, and Clarence Allen, California In-
stitute of Technology] Professors Perry Byerly and Donald Tocher,
University of California at Berkeley; Dr. Pierre St. Amand, China
Lake Naval Ordnance Test Station; the United States Coast and Geo-
detic Surveyj the United States Geological Survey; and the California
State Division of Mines and Geology.

Additional guidance in formulating departmental earthquake
engineering investigations and in developing rational factors for
earthquake-resistant design of hydraulic structures will be provided
by the recently constituted Consulting Board for Earthquake Analysis.
Dr. Hugo Benioff, Seismologist, California Institute of Technology,
specializing in seismic phenomena and instrumentation, is chairman of
the board. Members of the board include: Dr. George W. Housner, a
Structural Engineer, California Institute of Technology, specializing
in engineering seismology and earthquake-resistant design; Dr. Harry B.
Seed, Soils Mechanics, University of California at Berkeley, special-
izing in soil mechanics and model studies in connection with earth
dams; Mr. Nate D. Whitman, Jr., Consulting Engineer, specializing in
design of hydraulic structures; and Dr. James L, Sherard, Consulting
Engineer, specializing in the design of embankment dams.

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f INTRODUCTION

Bulletin No. II6-I has been prepared as a brief report to
the Legislature on the objectives, present accomplishments, and pro-
posed program of the department's Crustal Strain and Fault Movement
Investigation in the Division of Resources Planning. This activity
is a part of the department's overall program of earthquake investi-
gations. Specialized technical model and earthquake design studies,
which are conducted by the Division of Design and Construction and
' the Supervision of Dam Safety Office, are only briefly mentioned
herein. The data collected by the Crustal Strain Unit are utilized
by the Division of Design and Construction in their program for
developing earthquake design criteria for the State Water Facilities.
These data are also of value to the Supervision of Dam Safety Office,
the Division of Operations, and the planning activities of the
department.

This bulletin is the first of a series of reports which
will present the results of the various technical earthquake and
crustal movement studies being conducted in the Division of Resources
Planning. The first basic data report in the series will be Bulletin
No. 116-2, "Earthquake Epicenters and Faults in California,"

The Crustal Strain and Fault Movement Investigation was
Initiated by the department in January 1959. Funds for the Crustal
Strain Program are provided in the I962-63 budget, page 679, line 8.

CALIFORNIA EARTHQUAKES -- A SPORADIC PROBLEM

The California Water Plan envisions a system of reservoirs,
aqueducts, pumping plants, and. other hydraulic facilities throughout
the State. The potential threat to these structures posed by earth-
quakes and crustal movements is an important factor in the location,
design, construction, and operation of the various facilities of such
an extensive project. Inasmuch as precautionary aseismic design
measures entail additional expense, any appraisal of earthquake risk
must also include consideration of the purpose, type, and useful life
of the structure concerned, and the seriousness of the loss or the
danger to life should structural failure occur. The Department of
Water Resources has undertaken the Crustal Strain and Fault Movement
and other earthquake engineering Investigations herein described, to
provide objective evaluations of the potential hazards related to our
sporadic earthquakes, and to provide rational criteria for the design
of hydrauic structures to obviate or minimize any adverse effects
from future earthquakes.

Evaluation of earthquake activity indicates that California
is located in the second most highly seismic area in the United
States, the first being Alaska. The great majority of reported
earthquakes in California are associated with major fault systems
concentrated in the Coast Ranges in Central and Northern California,
in the Transverse and Peninsular Ranges in Southern California, and
in the Sierra Nevada. Locations of some of the known active faults
are shown diagrammatically on the Frontispiece and in Illustrations
1 and 2.

-3-

Illustration 1 shows an aerial view southeastward along
the San Andreas fault north of San Bernardino near the proposed
Devil's Canyon Powerplant No. 2. The earthquake of January 9, I857,
which was comparable In strength to the famous I906 San Francisco
earthquake, accompanied rupture and displacement of the ground along
the fault line In the area shown In the picture. The rupture ex-
tended northwesterly from San Bernardino about I50 miles or more,
following the trace of the fault through Antelope Valley, the moun
tains south of the San Joaquin Valley, and Carrlzo Plain.

Illustration 2 shows an aerial view of the San Andreas
fault near Carrlzo Plain, which Is located about 18 miles west and
northwest of Taft and is about I50 miles northwest of the area shown
in Illustration 1. The abrupt offsets of stream channels at the
fault line provide evidence of recent lateral fault movement. The
photo is typical of an area that will be crossed by the California
Aqueduct,

Effects of earthquakes which may damage hydraulic struc-
tures include: shaking of foundations, surface rupture, earth

lurches, slumps, raudflows, landslides, avalanches, seiches, and
seismic sea waves. Any one or a combination of these effects, if
not properly considered in design, could seriously Impair the use-
fulness of hydraulic structures. Crustal strain in the form of
tilting of the land surface occurs along some faults, and could
alter the hydraulic gradient of a canal or place a critical pumping
plant facility out of alignment without an actual earthquake. Never
theless, experience has shown that with proper evaluation of these

Illustration 1. San Andreas Fault , San Bernardino County (looking
boutheast). The San Andreas fault (indicated by arrows) forms the
boundary between the San Bernardino mountains on the left and the
alluvlum-f llled valley on the right.

-5-

■^^.

*-vN^*c3:-* -> ';

Illustration 2. San Andreas Fault , San Luis Obispo County (looking
east across fault) . The California Aqueduct will cross the San
Andreas fault in areas similar to the road crossing shown in the
center of the photograph. The fault is indicated by arrows.

factors Incorporated In design of hydraulic structures, these poten-
tial problems can be minimized.

Although California Is an area of high seismic activity,
a preliminary review of available data on hydraulic structures In
California Indicates that relatively few structures have been dam-
aged by earthquakes during the past 70 years. During this period,
l4 earthquakes caused some damage to 10 dams, 3 small water supply
reservoirs, 1 sewage treatment plant, 1 pumping plant, and 1 power-
plant. For example. In 19'^0 the All-Amerlcan Canal was displaced
14 feet 10 Inches by movement along the Imperial fault Just prior
to Initial use. Repairs were Immediately Implemented, and the canal
was then placed In operation. During the I906 San Andreas earth-
quake, displacements of 5 to 8 feet were measured In fills and out-
let tunnels of three earthflll dams In the Crystal Springs area
south of San Francisco where they were cut by the San Andreas fault.
It should be noted that these dams did not fall. Shaking of the
foundation and materials In Sheffield Dam (earthflll) in Santa
Barbara County during the 1925 earthquake caused failure of the
structure. The dam was rebuilt during the same year.

Reports of earthquake damage to hydraulic and other engin-
eering structures may be unintentionally misleading as to the extent
of the damage, because emphasis may be placed on the instances of
damage rather than on the number of structures which survive earth-
quakes unscathed. However, the past record of hydraulic structures
damaged by earthquakes is a reminder that damaging earthquakes have
occurred repeatedly in the past and can be expected to recur in the

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future. Therefore, planning, design, construction, and operation oi
the State Water Facilities must take into account all phases and
ramifications of earthquake phenomena to minimize the potential
damage from future earthquakes and to assure the safety of the
facilities.

-8«

REVIEW OP EARTHQUAKE INVESTIGATIONS IN CALIFORNIA

Even though the historical record of California earthquakes
extends back to 1769, It was not until I887 that systematic compila-
tion and publication of earthquake descriptions were Inaugurated.
This valuable program was undertaken by the University of California.
The first seismographs In California were Installed during the late
1880 's and early l890's at the following San Francisco Bay area
locations: Lick Observatory on Mt. Hamilton] University of Califor-
nia (Berkeley) j Chabot Observatory (Oakland); Mills Seminary (Oak-
land); and University of the Pacific (San Jose). Lick Observatory
began Its active work In I888 and was the early leader In collecting
reports of earthquakes on the Pacific Coast.

Following the destructive San Andreas earthquake and fire
which devastated San Francisco In I906, a State Earthquake Investi-
gation Commission was formed to study all aspects of the earthquake
and the resultant damage. Funds for operation of the commission and
publication of Its findings were provided by the Carnegie Institu-
tion of Washington, D, C, Soon after the earthquake, the United
States Coast and Geodetic Survey remeasured Its trlangulatlon net
In the area to determine the width of the zone affected by crustal
movement.

After publication of the report of the Earthquake Investi-
gation Commission, public "earthquake psychology" developed which
opposed discussion or investigation of earthquakes, because it was
"bad for business." In the midst of this opposition, a group of

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San Francisco Bay area geologists and others organized the Selsmo-
loglcal Society of America. Bulletins of that society have been
Issued quarterly since 19II. Funds to support earthquake Investiga-
tions in California came from outside the State during those lean
years -- largely from the Carnegie Institution of Washington. In
1921 the Carnegie Institution of Washington established a program
for earthquake recording and research, with headquarters in Pasadena
The torsion seismometer was developed for this work by J. A. Anderson
and H, 0, Wood, By the summer of 1927, four seismograph stations had
been installed in Southern California,

The damaging offshore submarine earthquake which struck
Santa Barbara in 1925 reawakened public Interest in earthquake inveS'
tlgations. As a result, new equipment was installed at the Universi
of California at Berkeley and at Lick Observatory. New stations wer
established at Stanford University and in San Francisco. In I925,
the United States Coast and Geodetic Survey began publishing descrip
tive notes of earthquakes which had formerly been published by the
United States Weather Bureau and Lick Observatory. Most of the earl
earthquake Investigations followed the lines of "pure science"
because of lack of public interest and funds for applied research.

In 1930, Stanford University and the United States Coast
and Geodetic Survey designed and built a large shaking table for
model studies. Even though the studies were useful in measuring the
effects of earthquakes on structures, the work was hampered by lack
of adequate funds, and subsequently was discontinued. About the
same time, the United States Coast and Geodetic Survey began making

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periodic geodetic measurements along and across the San Andreas fault
at a few critical localities with a view to accurately determining
the rate and direction of earth movements. Surveys across the fault
from Monterey to Pacheco Pass were made In 1930 and continued In 1932
In the area from San Luis Obispo to Lost Hills, and from San Fernando
to Bakersfleld. Other projects followed In subsequent years and are
being repeated at 10-year Intervals, supported by federal funds.

In 1932, the United States Coast and Geodetic Survey de-
signed and put Into operation a program for the Instrumental record-
ing of strong-motion earthquakes. Prior to that time, no appreciable
Instrumental data had been obtainable near earthquake epicenters
because the Initial shock always put sensitive seismographs out of
order. This Important development enabled the recording of earth-
quake data near the epicenters. The strong-motion seismographs have
been placed In strategic locations like "mousetraps" to lie In wait
for a strong shock. Unlike other sensitive Instruments, these strong-
motion Instruments are triggered Into operation by the Initial shock.
There are approximately 80 strong-motion seismographs located In the
State of California, centered largely In the metropolitan areas.

The California Institute of Technology has administered a
selsmologlcal program for Southern California since 1937- The Uni-
versity of California at Berkeley administers a similar selsmologlcal
program for Northern California. The United States Coast and Geo-
detic Survey has a separate statewide program. There Is a free and
Informal exchange of data between the organizations that Includes
copies of all seismograph records. As of 1956, the California

11-

Institute of Technology had l6 stations In operation, the Universits
of California had 11 stations, and the United States Coast and Geo-
detic Survey had one teleselsmlc station and about 80 strong-motion
stations. The universities are currently adding to their networks,

Activities of various organizations engaged in seismologic
investigations may be generally summarized as follows:

United States Coast and Geodetic Survey

1. Collection and publication of descriptive Information
on earthquakes.

2. Compilation of earthquake history.

3. Preparation and distribution of intensity maps of
strong earthquakes.

4. Operation of a network of strong-motion instruments
located primarily in metropolitan areas and at the sites of United
States Bureau of Reclamation dams.

5. Detennlnation of the natural frequency of vibration
of buildings and other structures.

6. Location of epicenters of the larger earthquakes.

7. Precise measurements across earthquake faults by
means of trlangulatlon, traverse, leveling, and astronomic azimuths,

8. Cooperation with universities and other agencies in
earthquake engineering investigations.

California Institute of Technology

1. Operation of a seismological laboratory.

2. Collection and publication of instrumental data on
earthquakes in Southern California.

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3. Compilation and study of earthquake history.

4. Operation of a network of seismographs.

5. Research In all problems related to earthquakes.

University of California at Berkeley

1, Operation of a selsmologlcal laboratory.

2, Collection and publication of Instrumental data on
earthquakes In Northern California.

3, Compilation and study of earthquake history,

4, Operation of a network of seismographs.

5, Research In all problems relating to earthquakes.

Stanford Research Institute

Instrumental recording of small shocks, determination of
epicenters, and other research activities.

Other Universities and Public Agencies

Activities by universities comprise essentially the
operation of a few seismographs and cooperation in epicenter and
intensity determinations. In addition, the California Department
of Public Works, Division of Architecture, in connection with its
administration of the Field Act, has spent approximately $200,000
in research on framed structures, and currently budgets as much as
$50,000 annually for this purpose. Other countries, notably Japan,
have contributed greatly to earthquake engineering research as ap-
plied to framed structures.

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Earthquake Engineering Research Institute

The United States Coast and Geodetic Survey, In 19^7, es-
tablished an Advisory Committee on Engineering Seismology to assist
the survey In Its selsmologlcal program. In 19^9^ the committee was
Incorporated with the title "Earthquake Engineering Research Insti-
tute." Its major purpose Is to function as an Independent Institu-
tion to promote continuing research In engineering seismology that
would lead to greater understanding of destructive earthquakes and
to Improvement In safety, and In the economical design, construction^
and location of structures of all types to resist forces Induced by
earth motion.

Activities of the Institute center largely on sponsoring
and/or promoting research and development by the Institute and
others, mainly In the field of framed structures, to which a consld
erable amount of research and study has been devoted. To date,
little emphasis by 'KERl has been placed on earthquake problems re-
lating to dams, canals, and other hydraulic structures.

.14-

DEPARTMENT CRUST AL STRAIN AND FAULT MOVEMENT INVESTIGATION

To achieve the most economic location and design of the
various proposed State Water Facilities commensurate with safety and
with an uninterrupted water supply, the Department of Water Resources
has undertaken an Investigation Into the nature and extent of the
potential problems which relate to earthquakes and crustal movements
In California, The various technical studies Involved In the depart-
ment's overall program of earthquake engineering Investigations have
been grouped Into two functional categories. The Crustal Strain and
Fault Movement Investigation comprises the first group of studies.
These largely Involve geology, seismology, and geodesy, and are aimed
toward obtaining knowledge of the seismic effects to be expected at
specific sites or within specified areas. The second group of stud-
ies Is more closely associated with structural and soils engineering
and is Intended to develop procedures for aselsmlc design and opera-
tion of hydraulic structures and for the Investigation of safety of
dams. Studies In the second group are within the responsibilities
of the Division of Design and Construction and the Supervision of
Dam Safety Office.

The Crustal Strain and Fault Movement Investigation was
Initiated by the department In January 1959* following Its endorse-
ment by Dr. Hugo Benloff, the department's chief selsmologlcal
consultant.

Scope and Objectives of Investigation

The earthquake data and earthquake hazard studies Included

In the Crustal Strain and Fault Movement Investigation In the Division

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of Resources Planning have the following objectives:

1. To Investigate, evaluate, and report on all phenomen
of earthquakes, faults, and crustal movements which may affect en^
gineering planning, design, construction, safety, and operation of
hydraulic facilities built by the department.

2. To develop rational seismic and crustal movement fac
tors which may be utilized in engineering design, based on frequer
and intensity of earthquakes, foundation conditions, probable crus
displacement, and associated considerations at each site as relate
to structural type and seriousness of loss, should structural dama
occur.

Intrinsic in the overall objectives are the following
specific objectives:

1. To determine the rate, constancy, and magnitude of
ground movements (accumulating crustal strain) near sites proposed
for hydraulic structures.

2. To locate active faults which may produce destructiv
earthquakes or along which the ground surface may rupture as the
result of accumulated crustal strain.

3. To estimate the destructive potential of the probabl
earthquake forces which should be anticipated at the site of each
structure constructed on or near active faults and on foundations
which vary in strength and stability.

4. To estimate the amount and direction of displacement
across active faults which may occur either abruptly or gradually
and which may sever or otherwise damage tunnels, conduits, or othe

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hydraulic structures, or Impede the movement of water by altering
the hydraulic gradient.

5. To locate areas of active tectonic uplift or subsidence
and to estimate the rate at which the resultant crustal tilting will
alter the hydraulic gradient of canals and thus change their capacity.

6. To develop and/or acquire and operate special instru-
ments and equipment of various types, which will implement the fore-
going. Such instruments are necessary in order to: (a) detect and
measure horizontal and vertical movements of the earth's crust j

(b) detect and record the crustal vibrations which may precede earth-
quakes and/or surface rupture j (c) measure and record the effects of
earthquakes on foundation materials at sites proposed for State Water
Facilities; and (d) measure and record the effects of earthquakes on
existing and proposed hydraulic structures.

7. To collect and compile basic data pertaining to earth-
quakes. Including epicentral locations, magnitude, ground vibration
frequencies, and earthquake effects on ground surface and on manmade
structures.

8. To prepare programs for electronic data machine proc-
essing, analysis, and plotting of data which will facilitate the
evaluation of earthquake and crustal movement factors.

9. To develop rational ground motion factors and criteria
which may be utilized in developing earthquake-resistant design of

'hydraulic structures.

10. To investigate the characteristics of, and potential
foi^ earthquake-generated seiches in reservoirs and aqueducts.

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Program Accomplishments to Date

The following are the principal activities and accompllsl:
ments to date of the department's Crustal Strain and Fault Movement
Investigation:

Fault and Earthquake Epicenter Map . A fault and earthqu
epicenter map of the entire State, the first of Its kind, has been
prepared and will be published shortly In Bulletin No. 116-2. Epl
centers of all earthquakes of Rlchter Magnitude 4 and above, which
have occurred In California and adjacent areas since 1932, are plot
ted on the map. The map graphically represents the relative sels-
mlclty of the various regions of the State during the past 30 years
and will greatly assist engineers, particularly those who design hy?
draullc structures and other types of engineering structures. In
appraising the earthquake hazard at various locations. Over 2,000
epicenters are plotted on the map, which shows groupings of eplcen^
ters In certain areas. Indicating potentially dangerous seismic
activity.

The same map shows the most complete delineation ever pub
llshed of faults throughout the State. The location of over 3,000
faults Is shown. The mapped faults represent a compilation of the
latest available geologic mapping, published and unpublished, by th
Department of Water Resources, the California State Division of Min^
and Geology, the United States Geological Survey, by other state an
federal agencies, and by other organizations and Individuals. The
information on fault locations on this map will be invaluable in
planning the location of hydraulic and other structures.

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The combination fault and epicenter map Is expected to
serve as a primary reference for applied seismology throughout the
State.

Earthquake Hazard Evaluations . Preliminary evaluations of
earthquake hazards at many of the sites of proposed hydraulic struc-
tures have been completed or are under way. Such studies include:
compilation of the earthquake history of the area, plotting of earth-
quake epicenters In the vicinity, analysis of the magnitude and In-
tensity of each earthquake, and evaluation of site foundation for
stability and susceptibility to shaking. Earthquake frequency. In-
tensity, and acceleration factors are estimated for each site to
provide design engineers with a basis for aselsmlc design of hydrau-
lic structures. These studies also Include consideration of some of
the side effects of earthquakes which can cause damage, such as sur-
face rupture, slumps, landslides, earth or mud flows, seismic sea
waves, and waves generated within reservoir areas.

Electronic Data Processing , A new method of tabulating
earthquake data has been developed which utilizes electronic data
processing equipment. The latitude and longitude, date, time, ac-
curacy of epicenter plot, and magnitude of earthquakes occurring from
1932 through i960 have been placed on IBM cards. A tabulation of the
earthquake data is Included in Bulletin No. 116-2.

Until now such data were not available for the entire State
in the files of a single agency, but were scattered in the files of
various agencies which have collected and analyzed them for specific
areas and purposes. It is now possible to obtain and reproduce the

•19-

earthquake record of any area accurately and rapidly. Utilization
of the data processing machines will permit machine plotting of epi'
centers on maps and enable the compilation and plotting of accumula^
tive earthquake energy release for any desired area.

Technical Reports . An annotated bibliography on engineer'
ing seismology as applied to hydraulic structures and on earthquake
damage to hydraulic structures is being prepared. Selected technical
reports are summarized in sufficient detail to provide essential dat|
as well as descriptions of instrumentation and procedures. In addi-t
tion to providing the results of the investigations and research coni
ducted by other agencies, such a bibliography will provide a basis
for determining which lines of investigation should be pursued fur-
ther to satisfy the department's requirements in connection with the,
planning, design, and operation of hydraulic structures.

Geodlmeter Survey . Through the use of a geodimeter which
may be generally described as the most precise distance-measuring
device available, 65 lines crossing nine faults between San Prancisc
and Indio have been established. The locations of these lines are
shown on Plate 1, titled "Crustal Strain and Fault Movement Investi
gation Geodetic Program." The purpose of these geodetic studies is
to measure horizontal movements of the earth's crust due to strain
build-up or fault slippage near the location of present and proposed
hydraulic structures, to delimit areas or zones thus affected, and
to detect strain build-up that may be released by large earthquake-
producing fault displacements. The geodimeter lines are remeasured
to determine the rate, direction, and constancy of differential horl
zontal movements of the crust on opposite sides of the fault.

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Emphasis has been on measurements across the San Andreas fault; most
of the other faults crossed are related parallel faults. Most of the
geodlmeter lines have been surveyed three times, representing approxi-
mately 2,600 miles of surveying over a period of three years. It
should be pointed out that the data accumulated during this brief
period are Insufficient to warrant positive conclusions. However, a
preliminary evaluation of measurements across the San Andreas fault
suggests right lateral movement (the west side moving northward rela-
tive to the east side) between Holllster and Slmmler. The few re-
peat measurements available between Slmmler and the Intersection of
the San Andreas and Qarlock faults suggest left lateral movement.
South of the Garlock fault. It has not been possible to establish a
consistent pattern of movement. Repetition of the measurements will,
of course, be continued to confirm or revise these preliminary evalu-
ations, and to establish more definite directions, amounts, and, pos-
sibly, variations of magnitude In the movements.

Trlangulatlon Survey . Through the cooperation of the
United States Coast and Geodetic Survey, an extremely precise trl-
angulatlon network has been established covering the area of the San
Andreas, Garlock, White Wolf, and other faults which converge near
the extreme southern end of the San Joaquin Valley. The trlangula-
tlon network Is shown on Plate 1. Repetition of the trlangulatlon
will be accomplished after the geodlmeter measurements, previously
described. Indicate that sufficient ground movement has taken place
to warrant the re survey.

-21-

Federal-State Cooperative Subsidence Leveling Program !|

The cooperative leveling program for the measurement of

deep subsidence has been sponsored by the department for a number ci

years to obtain precise data on changes In elevation of the land s{\

face In several areas of the State. The current program Is dlrecte;

I
toward obtaining such data In those areas of the San Joaquin Vallejj

and the Sacramento-San Joaquin Delta which are critical to the desj
and operation of the presently authorized State Water Facilities.
The program Is administered by the Crustal Strain Unit In the Dlvls
of Resources Planning, Funds for the cooperative program are pro-
vided In the 1962-63 budget on page 678^ line 40.

The principal cause of deep subsidence In the San Joaquir:
Valley Is attributed to withdrawal of ground water. Vertical tec-
tonic movement also Is thought to be a contributing factor In land j
subsidence In some areas such as at the south end of the San Joaqulj
Valley near the base of Wheeler Ridge. In either case, the potent
adverse effect on aqueduct gradients locally will be the same as t.
discussed under tectonic movement as measured by tlltmeters. It Is
critical for the department to know the varying rates of land sub-
sidence along the aqueduct route so that allowances for this factor
may be made during design and construction of the facilities to mln
mlze the adjustments which may become necessary after the facllltle
are placed In operation.

Future Program

The department's seismic Investigations, as recommended b
the Consulting Board for Earthquake Analysis, Include continuation

-22-

of the foregoing activities of the Crustal Strain and Fault Movement
Program and Implementation of additional studies employing Instru-
mentation and engineering models. The solution to earthquake engin-
eering problems requires an Integrated program of studies in the
following fields: applied seismology, geodesy, engineering geology,
and aselsmic engineering design. These studies comprise the major
phases of the department's future investigational programs.

As mentioned earlier, all of the department's present and
proposed studies have been grouped into two functional categories.
Studies which fall in the first category and which have been assigned
to the Crustal Strain and Fault Movement Investigation in the Division
of Resources Planning are discussed under the following headings:
Applied Seismology Studies, Geodetic Studies, and Engineering Geology
Studies. Studies which have been assigned to the second category and
which are the responsibility of the Division of Design and Construc-
tion and the Supervision of Dam Safety Office, are presented in the
next chapter under the heading. Departmental Earthquake Engineering
Studies.

Applied Seismology Studies . Studies of the phenomena
associated with earthquakes, and the behavior of foundation materials
and hydraulic structures during earthquakes, comprise the keystone in
establishing aselsmic design criteria. The following seismological
studies are part of the future program in the Crustal Strain
Investigation:

1. Seismological field studies involving various types
of seismic instrumentation will be a major effort of the dopartment ' s

-23-

program in securing Information on ground, motion characteristics.
The following field instrumentation program is under way or in the
final planning stages:

a. Installation and operation of a series of
strong-motion seismograph assemblies includ-
ing accelerometers and. displacement meters,
and supporting seismoscopes. These instru-
ments will be established in critical areas
throughout the State and maintained for an
approximate 10-year period or longer. In
the event of a large earthquake, these in-
struments will provide valuable design data
which cannot be secured from the sensitive
instruments. In most major earthquakes ,
sensitive instruments are commonly rendered
inoperative.

b. Installation and operation of portable high-
sensitivity seismographs for use in deter-
mining the ground spectral amplification
factor for critical sites and for determin-
ing the spectral response characteristics

of selected existing dams. Two high-
sensitivity seismographs will be acquired
and used at individual structure sites.
Where such sites are underlain by alluvium
or by slightly to moderately compacted

-24-

sediments, one seismograph will be located
on the proposed site, and a second Instru-
ment will be located on rock in the near
vicinity of the site. Frequency curves
for design use can be compiled by digitiz-
ing records from the two seismographs.
Maintenance of these instruments at a pro-
posed site during several smaller earth-
quakes will provide adequate data for
design, thus allowing seismographs to be
moved to other structure sites.
Installation and operation of a fused-
quartz strain extensometer at the recently
acquired site in Antelope Valley, Los
Angeles County, about l4 miles southeast
of Gorman. This instrument will provide
a record of the accumulation of strain in
bedrock in the wedge-shaped crustal block
between the San Andreas and Garlock faults.
Earthquakes and surface rupture are the
predicted effects which will occur when
the accumulating strain is suddenly re-
leased. It will also record the transient
strains induced in bedrock during the
passage of earthquake waves.
Installation and operation of tripartite
tiltmeters to determine the direction and
-25-

rate of tilt along the alignment of aque-
duct routes and at other critical locations
such as pumping plant sites. Tlltmeters
will be located in tectonlcally active areas,
and measurements repeated at periodic inter-
vals, in order to evaluate the extent and
the magnitude of the problem.
Installation and operation of permanent
seismograph stations associated with State
Water Facilities* A class A seismograph
station is presently under construction at
Oroville Dam, Butte County. This station
will provide a continuous record of earth-
quake activity in the Oroville and adjacent
areas with respect to the dam and appurte-
nant structures. Data from this station ivill
be useful in establishing seismic design
criteria for projects contemplated under the
State Water Resources Development System.
Installation and operation of the recently
acquired variable reluctance transducer seis-
mograph on the San Andreas fault or in an
area of the State, such as the North Coastal
area, where seismograph records are insuf-
ficient or are not available. A sensitive
seismograph station at such a site (l) will

-26-

monitor some of the local "rock noises"
or microtremors generated by nearby active
faults which may be the precursor of a
major earthquake, (2) will assist in deter-
mining epicentral locations of all earth-
quakes in the area, and (3) will furnish
data on ground motion characteristics at
the site.
2. Selsmological office studies will be undertaken as
needed in order to evaluate seismic hazards at proposed structure
sites. Studies undertaken may include, but not necessarily be
limited to, the following:

a. Continuing collection and processing of
basic data on earthquakes. Including their
effects on ground surface and on manmade
structures, and programming the earthquake
data for machine analysis. Coordination
with universities and the Coast and Geo-
detic Survey will be continued to obtain
all available seismological data pertinent
to the program,

b. Development of special types of earthquake
data maps in the future at critical struc-
ture sites or areas. The preparation of
these special maps depicting magnitude,
intensity, and acceleration, and the analy-
sis of their correlation and interrelationship

-27-

with the phenomena and. expression of strain
energy release, are steps in the development
of rational factors for earthquake-resistant
engineering design of State Water Facilities,
Some of the special maps which might be
compiled Include:

(1) Maps depicting eplcentral locations
of earthquakes below Rlchter Magni-
tude 4, These small earthquakes
are the result of minor adjustments
in the earth's crust. Such earth-
quakes release a small, but appre-
ciable, portion of the elastic
strain energy which accumulates
in the earth's crust as the result
of crustal movements. Thses smal^l
earthquakes also reflect adjust-
ments in the crust which are the
consequence of the rapid release
of accumulated strain energy dur-
ing major earthquakes. The pat-
tern which develops by plotting
the epicenters of small earth-
quakes may provide a clue to the
mechanism involved in the strain
build-up which results in major

earthquakes .

-28-

(2) Earthquake intensity maps depleting
areas In which earthquake damage has
been reported or which have been
subjected to moderate to Intense
shaking. Such a map may be useful
In developing rapld^ qualitative
appraisals of the earthquake hazards
at sites of proposed facilities of
the State Water Resources Develop-
ment System.

(3) Maps depleting cumulative earthquake
energy release. The map would show
graphically whether strain energy Is
being released by numerous minor
earthquakes along some faults or
segments of faults or by only a few
major earthquakes along other faults
or fault segments. Thus, the rela-
tive seismic activity of a proposed
site could be compared with adjacent
areas. This map will assist In plan-
ning the location and design of hy-
draulic structures by providing a
numerical basis for appraising the
earthquake hazard In any area In
terms of the rate at which earth-
quake energy Is released.

-29-

3. The Consulting Board for Earthquake Analysis has recc
mended that the department undertake a study of long-period standlr
waves (seiches) which may be generated In reservoirs as a result of
earthquake activity. The department's studies will encompass anal^
sis and evaluation of existing seismograph records and the design.
Installation, and operation of special Instrumentation to measure
seiches In reservoirs throughout the State. Correlation of the rec
ords from the seiche recorders with records from long-period seismc
graphs will enable the department to determine the probability of
seiche development In each reservoir and whether the seiches genera
by a strong earthquake may be In any way destructive. These studle
may be a joint effort of the Divisions of Resources Planning and
Design and Construction.

Geodetic Studies . The measurement of vertical and hori-
zontal movements of the earth's crust, using geodetic instruments a
techniques, is another essential phase of the department's program
for investigating and evaluating the problem of accumulating crusta
strain. The following studies and activities will be continued a^
part of the geodetic phase of the Crustal Strain Investigation:

1. The department's program of geodlmeter measurements
will be repeated along the San Andreas fault. These measurements
are being improved by the adaptation of new techniques for obtalninj
midline atmospheric measurements. It is planned to extend the
department's program of geodlmeter measurements to other areas of
the State where water development facilities are close to other
active faults. These measurements will assist In distinguishing

-30-

active from Inactive faults and will show the various rates at which
parts of the earth's crust are undergoing horizontal movements.

2. Coordination of state and federal earthquake engineer-
ing survey programs will be continued. Inasmuch as the United States
Coast and Geodetic Survey has been given primary responsibility for
long-term earthquake triangulatlon surveys by acu of Congress, coor-
dination is necessary to eliminate overlapping and duplication and to
lend more specific direction to the federally financed geodetic pro-
grams. Federal programs Include fault zone triangulatlon and astro-
nomic azimuths for the measurement of horizontal crustal movements,
and precise leveling to detect vertical movements.

3. The cooperative ultrapreclse triangulatlon project of
the department and the United States Coast and Geodetic Survey for
measurement of horizontal movements in the area of junction and near
approach of the San Andreas, Garlock, and White Wolf faults will be
repeated when the department's geodlmeter measurements indicate suf-
ficient crustal movement to warrant the repetition.

4. The Federal-State Cooperative Leveling Program for
Subsidence, administered by the department. Is another area of coop-
ration with the United States Coast and Geodetic Survey. This pro-
gram provides basic data on subsidence for planning and design
sngineers in the department, and for other Interested agencies. This

ooperative program will be continued.

5. The proposed Federal-State Cooperative Selsmologlc and
leodetic Programs for Earthquake Engineering, with the United States

oast and Geodetic Survey, will provide complete analysis and inter-
pretation of already completed field work of special geodetic repeat

-31-

observations in California fault zones, analyses of existing strong-
motion seismograph records of California earthquakes, and additional
special geodetic repeat observations and analyses in fault zones in
the vicinity of proposed State Water Pacillties, The survey will
continue to operate and maintain the seismograph stations that have
been made part of the cooperative program, and will supply personnel
and services to install, operate, maintain, and interpret records of
several of the seismographic Instruments and stations recommended by
the Consulting Board for Earthquake Analysis. This cooperative pro-
gram does not duplicate the department's Crustal Strain Program, but
is an essential complement thereto.

Engineering Geology Studies . Geologic studies are an es-
sential phase of any thorough study of the hazards of earthquakes an
crustal movements to manmade structures. Engineering geologists hav
a public responsibility to ensure that engineers, architects, proper
owners, and public officials are properly informed with respect to |
earthquake hazards, without being too reassuring or needlessly alarni
Ing. A clear idea must be formed of the long-term nature of earth-
quake risk, as well as its relation to the location of faults and to
the character of the ground or foundation. The following activities
and studies are included in the geologic phase of the Crustal Strain-
Investigation:

1, Detailed seismic microregionalization maps may be
developed for specific sites and/or critical areas. This will
entail compilation of the following types of data:

a. Detailed information on potential activity

of faults with particular emphasis on those ij

-32- 1

faults which may affect existing and proposed
hydraulic structures,
b. Characteristics of foundation rocks and
materials relative to seismic stability.
These data and seismic microregionalization maps are im-
portant in any earthquake engineering study, and will be most useful
in appraising the earthquake and crustal movement hazards at sites
of proposed facilities of the State Water Resources Development
System.

2. Geologic interpretation will be provided for the strain
build-up detected by the geodetic and geophysical measurements being
made in other phases of the investigation.

3. Geologic field studies will Include reconnaissance of
possible sites for future geodlmeter or other geodetic stations, or
for future installations of geophysical instrumentation such as
seismographs, quartz-strain extensometers, recording tlltmeters,
accelerograph, and related types of instrumentation recommended by
the department's Consulting Board for Earthquake Analysis.

4. Sites chosen for water development facilities through-
out the State will be inspected as part of the department's earth-
quake hazard evaluation studies, and a geologic evaluation of the
earthquake and/or crustal movement hazards will be made at such
sites.

•33-

DEPARTMENT EARTHQUAKE ENGINEERING INVESTIGATIONS

The primary function of the earthquake engineering studies
to be conducted by the Division of Design and Construction and the
Supervision of Dam Safety Office will be the development of procedure:
and criteria for aselsmlc design of features of the California Water
Resources Development System and for Investigation of dams under
Jurisdiction of the department's Supervision of Dam Safety Office
from the seismic standpoint. These studies will utilize the afore-
mentioned earthquake hazard studies to obtain an appreciation of the
earthquake hazards which should be anticipated In any given area.
The Division of Design and Construction has completed a
proof test of the Orovllle embankment design. This seismic model
study was one of several essential engineering studies which have
been completed In connection with the design of Orovllle Dam. This

: proof test of the embankment design was conducted on the shaking
table of the Engineering Materials Laboratory on the Berkeley campus

. of the University of California, IJie report on this seismic model

, study will soon be completed

In Its report of November 19, 1962, the Consulting Board

! for Earthquake Analysis recommended that the department undertake

the following earthquake engineering Investigations In addition to

the basic studies previously discussed:

"l. Experimental investigations of the strength and
deformation characteristics of soils under simu-
lated earthquake loading conditions for the purpose
of determining the appropriate soil properties for
use in analyses of earthquake response character-
istics. Studies should include:

-35-

" (a) Investigations of the strength and de-
formation characteristics of soils under
combined static and pulsating loads.

" (b) Investigations of volume changes and
strength characteristics of saturated
granular materials under combined shear
and vibratory loading conditions and
also under high confining pressure con-
ditions associated with large dams with
the object of determining the pore pres-
sures likely to develop in embankments
composed of saturated granular materials
during earthquakes. These studies should
be supplemented by investigations of
volume changes induced in dry granular
materials by typical earthquake ground
motions with the object of throwing some
light on the extent of subsidence of
such soils as a result of earthquakes,

"2. Investigation of methods for predicting the danger of
liquefaction of soils both in the laboratory and in
the field. This investigation is closely related to
that suggested in 1 (b) above.

" 3. Investigation of the stability and deformation of model
dams during simulated earthquake motions induced by a
shaking table. Such studies would serve two purposes.

" (a) As an interim procedure, tests on models
of proposed prototypes would provide a
guide to the probable effect of earth-
quakes on these structures. However,
this would only be possible for certain
types of embankments.

" (b) The results would provide data for de-
termining the applicability of analyses
and measured soil characteristics for
predicting the response of embankments
and dams to known ground motions. With-
out such tests it is difficult to see
how analytical procedures can ever be
checked under controlled conditions.

"4. Investigation of the stability against surface sliding
of banks of granular materials subjected to earthquake
ground motions, for the purpose of checking the appli-
cability of available analyses for computing the ac-
celeration at which sliding is likely to occur and

-36-

for determining the extent of sliding and flattening
of slopes resulting from a given ground motion.

"5= Investigations of the dynamic behavior of dams by the
methods of analytical mechanics. Analyses of the
elastic response of dams and embankments have been
developed, but studies of elastic-plastic response
are required to determine the stresses and displace-
ments resulting from known earthquake ground motions.
It is the inelastic displacements which are of pri-
mary Importance in stability analyses.

"6. Investigations of the dynamic behavior of existing

dams by means of field tests using a shaking machine.
The results of such studies can be Interpreted to
evaluate the dynamic shear modulus of the soil com-
prising the dam and can thus be used to check the
validity of laboratory methods for determining the
dynamic shear modulus of the soils in advance of
construction. "

The Crustal Strain and Fault Movement Investigation and the

Dther earthquake engineering Investigations herein briefly described,

lave been undertaken by the Department of Water Resources to provide

Dbjectlve evaluations of possible hazards at hydraulic structure

sites as related to the potential effects of California's sporadic

arthquakes and to develop rational criteria for aseismic design of

structures at those sites to obviate or minimize the adverse effects

of future earthquakes. Utilization of the data on earthquake hazards

and the criteria for aseismic design will contribute to the competent

design of safe and economical hydraulic structures in all areas of

the State.

-37-

/f ^

CRUSTAL STRAIN AND

FAULT MOVEMENT INVESTIGATION

GEODETIC PROGRAM

1959-1962

THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW

RENEWED BOOKS ARE SUBJECT TO IMMEDIATE
RECALL

RET. tifcB 1 1) 19B5

VIAR

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'1 REC'D

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