l//-sl2 · 3/31/1977 · 27595 sanla fe street hemet, california 92343 (7h) 658-7509 chy of desert...

/l//-Sl2 STATE OF CALIFOlil:NIA-THE RESOURCES AGENCY

DEPARTMENT OF CONSERVATION

DIVISION OF MINES AND GEOLOGY DIVISION HEADQUARTERS RESOURCES BUILDING, ROOM 13'1 1416 NINTH STREET SJICRAMENTO, CA 95814

Dl1trlct Off1iei!11: LOS ANGELES Junip•ro S.rra Bldg., Rm. 1065 107 South lrogdway 9001'

Mr. John D. Conlin

SJICRAMENTO Re1ource1 Bldg., Rm. 118 1416 Ninth StJ"Mt 95814

CI ty of Desert Hot Springs 11711 West Drive Desert Hot Springs, CA 9224o

Dear Hr, Conlin:

SAN FRANCISCO Ferr~ Building 94111

(415) 557-0413

November 10, 1977

l:DMUND G. BROWN JM., GciY•rJJCllr

We are placing on open file the following reports, reviewed and approved by the City of Desert Hot Springs In compliance with the Alquist-Priolo Special Studies Zones Act:

Subsurface engineering geology investigation, San Diego Federal Savings and Loan Branch Office, Desert Hot Springs, California; by G. S. Rasmussen; 4/24/7'{,

Subsurface engineering geology Investigation, Assembly of God Church, Desert Hot Springs, CA; by G.S. Rasmussen; 4/30/75.

Engineering geology investigation, Temple N'Vey Shalom addition, Desert Hot Springs, CA; by G,S. Rasmussen; 12/10/75.

Engineering geology investigation, Retirement Center, NW Corner Second Street and Ocotillo Road, Desert Hot Springs, California; by G.S. Rasmussen; 1/29/76.

Engineering geology investigation, proposed commercial building for Robert W. Dye, Desert Hot Springs, California; by G.S. Rasmussen; 3/31/77. ·

In the future, it would be appreciated If these reports were submitted within 30 days of acceptance as required.

EWH/mkr

cc: A-P fl 1 e.,-' J.D. Fett

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Sincerely yours,

EARL W. HART Office of the State Geologist CEG 935

I

GEOLOGY GrorHYSICS S~tSMOLOGV

Earth Science S Engineering f)P-572 27595 Sanla Fe Street

Hemet, California 92343

(7H) 658-7509

CHy of Desert Hot Springs 11711 West Drive Desert Hot Springs, CA 92240

Attention John D. Conlin

Gentlemen:

September 8, 1977

At your request we have reviewed the roport by G. Rassmussen dated March 31, l !)77 and entitled:

Engineering Geology Investigation, Proposed Commercial Building, Robert W. Dye, Desert Hot Springs, California

The property is located at the northwest corner of Palm Drive and Desert View Avenue.

ENfilNEE.RING OLE.ANOGRAi'HY HYDROl,O(;y

It is our opinion that the investigation and report have been performed according to the present state-of-the-art and complies with the requirements of the Alquist-Prlolo geologic hazards zono act.

Respectfully, Earth Science & Engineering, Inc.

--ef ~ D Y:.£ <~

John D. Fett, President Cert. Engineering Geologist 858

JF:jl Copy: G. Rasmussen

GEOLOGY GEOPHYSICS SEISMOJ,.OGY

Earth Science fi Engineering 27595 Santa Fe StrE!el

Hemet, California 92343

(714) 653·7509

City of Desert Hot Springs 11711 West Drive Desert Hot Springs, CA 92240

Attention John D. Conlin

STATEMENT

September 8, 1977

ENGINEERING

OCfANOGR,\PHV HYDROLOGY

Review Rasmusson & Associates report dated March 31, 1977 entitled Engineering Geology Investigation, Proposed Commercial Building Robert W. Dye.

Located at the Northwest corner of Palm Drive and Desert View Ave.

3/4 Hour @ $40.00 Report reproduction, clerical and postage

$30.00 9.17

$39.17

I I I I I I I I I I I I I I I I I I I

GARY S. RASMUSSEN & ASSOCIATES /ENGINEERING GEOLOGY

POST OFFICE BOX N • IS6!5 NORTI-! WILL.OW AVENUE • RIAL'l'O, CAl...IF'ORNIA 92876 • (714) 87!1-0906

ENGINEERING GEOLOGY INVESTIGATION PROPOSED COMMERCIAL BUILDING

ROBERT W. DYE DESERT HOT SPRINGS, CALIFORNIA

March 31, 1977

Project No. 1186

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Prepared for

Robert W. Dye 1146 Olancha Drive

Los Angeles, California 90065


GARY S. RASMUSSEN & ASSOCIATES / ENGINERlllNG GEOLOGY

POST OFFICE SOX N • 186" NORTH WILLOW AV'°NUE • RIAL.TO. Cl\LIFORNIA 923'71:5 • 1714) ~!,.'l~~O~Oti

March 31, 1977

Robert W. Dye Project No. 1186 1146 Olancha Drive Los Angeles, California 90065

Subject: Engineering Geology Investigation, Proposed Commercial Building, NW Corner of Palm Drive and Desert View Avenue, Desert Hot Springs, California.

A subsurface geologic investigation of the SS' x 140' parcel was con

ducted at your request. The purpose of our investigation was to determine

if any active faults pass through the proposed building location. We

understand a single-story, commercial structure will be built at the

location shown on the enclosed 20-scale map. A single,backhoe trench was

excavated across the proposed building area to determine the presence

or absence of active faulting in the upper 10 feet of sediments. The

area covered by our investigation is limited to the northwest trending zone

shown on the enclosed 20-scale map (the southwest portion of the site

outside of the zone covered by trenching, has not been proven free of

active faulting). The location of the site is shown on the index map

on page 2 and on the 400-scale topographic map enclosed with this report.

The site was free of man-made structures and vegetation at the time of

our investigation. The location of the proposed structure was deter

mined in the field by measuring from existing curbs with a steel tape.

The field location was based on measurements provided by the builder,

Oscar Aiken. A parking area is to be provided west of the proposed

structure.

The site lies within a zone of known active faults as determined by the

Alquist-Priolo Special Studies Zone Act. The approximate limits of the

Special Studies Zone are shown on the index map on page 2. The active,

Mission Creek fault lies approximately 400 feet northeast of the north

east corner of the site, based on an obvious lineation that appears on

older aerial photographs.

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INDEX MAP Robert W. Dye

Desert Hot Springs, California -······ Fault, Dashed where

dotted where approx. buried

Base Map--USGS 1"~2000•

Project No. 1186

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Gacy S." Rasmussen Ii Associates, Inc.

.. ' '


Robert Dye-Commercial Building-Desert Hot Springs March 31, 1977

SITE INVESTIGATION

Project No. 1186

The backhoe trench was excavated at the location shown on the enclosed

20-scale map. The trench was placed so that any active, northwest

trending faults, such as are known to exist in the area, would have to

pass through the trench if the fault exists under the proposed building

site. Our subsurface investigation only includes the area within the

limits shown on the enclosed 20-scale map and does not apply to any

active faults that may exist just beyond those limits.

In addition to the subsurface exploration trench, our investigation

included a geologic field reconnaissance of the site and surrounding

area; review of stereoscopic aerial photographs flown in 1939; review

of infra-red stereoscopic aerial photographs flown in 1971; review of

pertinent geological literature and maps; and review of significant

seismic data. A list of references is enclosed.

SITE GEOLOGY

The proposed structure will be located on Recent alluvium approximately

one mile southwest of the southwest flank of the Little San Bernardino

Mountai,ns. The sediments observed in the trench were probably deposited

by alluvial streams emanating from the mouth of Blind Canyon, approximately

one mile to the north. The coarse-grained sediments observed in the trench

walls are typical alluvial fan deposits commonly found near the base

of mountain ranges in desert areas.

The ground surface slopes downward toward the south at a rate of approxi

mately 3 per cent. The backhoe trench was entered and logged in detail.

The log of the materials observed in the trench walls is enclosed with

this report. The trench was flooded and the backfill material placed in

shallow lifts during the flooding operation. Approximately 10,300

gallons of water were used during flooding and backfilling of the trench.

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Project No. 1186

The full depth of the trench was carefully examined for evidence of Recent

faulting, and none was observed. Nearly horizontal to south sloping bedding

and laminae could be observed throughout the trench. Any disruptions or

offsets due to faulting should have been observable in the bedded

portions of the units. Although the exact age of the sediments at a

depth of 10 feet is not known, they are estimated to be at least

several thousand years old.

SEISMIC SETTING

The location of the Mission Creek fault (a branch of the San Andreas

fault zone) has been plotted at approximately 400 feet northeast of the

proposed northeast building corner by Richard Proctor, 1968. Our

observation of the 1939 aerial photographs, taken prior to development

of the area, indicates the Mission Creek fault lies at the location plotted

by Proctor and as shown on the Special Studies Zone map. No clear evidence

of the fault's location in this area has been documented other than the

vegetational lineation on the older aerial photographs. This lineation

does line up with a possible southwest-facing fault scarp just west of

Northwest Drive and Eighth Street.

The Miracle Hill fault, a branch of the Mission Creek-San Andreas fault

zone, is shown northeast of the Mission Creek fault on the Special

Studies Zone map. Observation of the 1939 photos, suggests that the

Miracle Hill fault trends more westerly than shown on the Special Studies

Zone map and probably merges with the Mission Creek fault due east of the

site.· The Miracle Hill fault does not appear to rupture Recent alluvium,

as does the Mission Creek fault, based on observation of the photos.

The Mission Creek fault is considered to be an active fault in this area

and has had historic earthquakes along it.

Other faults in the area include the northwest-west trending Banning

fault, approximately 4 miles to the southwest, and the north-northwest

-4-0.A.RY S. l't.A.Sl><tUSSl!lN & ASS=:r.AT:WS


Robert Dye-Col!lillercial Building-Desert Hot Springs March 31, 1977

Project No. 1186

trending Blind Canyon fault, approximately one mile to the northeast. The

Banning and Mission Creek faults are considered to be the two main

branches of the San Andreas fault zone in the upper Coachella Valley

area (Desert Hot Springs area).

Additional active faults are located within the general region, such as

the Pinto Mountain fault to the north and northeast, but because of

their much greater distance from the site and lower or equal maximum

probable earthquakes expected, they are not considered significant when

compared to the nearby traces of the San Andreas fault zone (Mission

Creek fault).

SEISMIC HISTORY

Numerous earthquakes up to Richter magnitude 5.8 have occurred along the

San Andreas and Pinto Mountain fault zones in the general region.

Probably the most significant historic earthquake in the area was the

Richter magnitude 6.5, Desert Hot Springs earthquake of December 4, 1948.

The epicenter of this earthquake was located approximately 6 miles south

east of the site. Although the epicenter of this earthquake was located

in the foothills of the Little San Bernardino Mountains, the subsurface

movement or origin of the earthquake is believed to have occurred along

the Mission Creek fault at depth (Richter, et • .!.!_., 1958; Proctor, 1968).

Therefore, the effective point of energy release at the surface may have

been considerably closer to the site.

Earthquakes of magnitude 6,Q and greater commonly result in surface

rupture along faults in California. However, no surface rupture along

the Mission Creek or related faults was reported after the 1948 earth

quake (Proctor, 1968).

The Imperial Valley earthquake of 1940 has been reported with Richter

magnitudes ranging from 6.7 to 7.1. This earthquake also originated

along the San Andreas fault zone. Therefore, at least two earthquakes

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0-.A.:A.Y S. RASMUSSlDN .!I:; .ASSOCIATB:B


Robert Dye~Commercial Building-Desert Hot Springs March 31, 1977

Project No. 1186

of Richter magnitude 6.5 to 7.1 have occurred along the San Andreas fault

zone in this region in the last 35 years.

SEISMIC ANALYSIS

The nearby Mission Creek fault is considered to be an active fault, based

on both surficial evidence and seismic history. The Banning fault is

also considered to be active, as historic earthquakes up to Richter

magnitude 5.5 have occurred along it. Because of the abundant evidence

of activity along these two faults and the two large historic earthquakes

along the San.Andreas fault zone previously mentioned, the probability

of a large earthquake in the area w.ithin the next 100 years seems quite

high.

Recurrence intervals for maximum probable earthquakes cannot yet be

precisely determined from a statistical standpoint, as recorded

information on siesmic activity does not encompass a sufficient span

of time. However, based on information available at this time, it is

our opinion that a Richter magnitude 7.5 earthquake, originating along

one or more branches of the San Andreas fault zone in this area (Mission

Creek, Banning, and related faults) should be expected within the next

100 years (at least SO percent chance of occurence). An earthquake of

this magnitude and distance from the site can be expected to produce

maximum ground accelerations in bedrock under the site of approximately

0.7g. This acceleration should not necessarily be used as a design value

as it is a peak acceleration and is estimated for bedrock (estimated to

be more than 1,000 feet deep under the site).

FLOODING

The older photographs indicate the area has been subject to flooding

during historic times. The large grain size of the subsurface materials

including small boulders, indicate the site has been subject to periods

of flooding in the Recent geologic past. The flood control channel north

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I I I I I I I I I I I I • . , I I I I I I


Project No. 1186

of town and existing man-made improvements should help to mitigate the

flood hazard on the site.

CONCLUSIONS

Ground rupture due to faulting is not expected through the proposed building

site as no evidence of Recent faulting through the area trenched was

found during our investigation.

No active faults pass through the proposed building area that have dis~

rupted the upper 10 feet of alluvium on the site, as determined by

trenching.

Severe seismic shaking of the site should be expected in the next

100 years.

Earthquake induced flooding of the site is not likely as no large bodies

of water exist above the site, other than water in the Colorado River

Aqueduct.

Liquefaction and other shallow ground water hazards are not expected

as the ground water table is at least 100 feet deep .

Earthquake induced landslides or mud flows are not likely due to the

distance to the nearest steep slopes and existing flood control channel.

Cracking of most buildings and parking lots in Desert Hot Springs may

be evidence of subsidence of the area due to ground water withdrawal.

No documentation of this phenom.ena exists for this area but is common

i.n other areas where similar conditions exist.

RECOMMENDATIONS

A maximum probable earthquake of Richter magnitude 7.5 is expected

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I I I I I I I I I I I I •• I I I I I I

Robert Oye-Conunercial Building-Desert Hot Springs March 31, 1977

Project No. 1186

along one or more branches of the San Andreas fault zone in this area,

therefore we reconunend that human occupancy structures be designed

accordingly.

Human occupancy structures should not be placed outside of the limits of

the area trenched, unless additional trenching shows those areas to be

free from fault rupture.

Encl; 400-scale map 20-scale map References Trench log

Dist: Robert W. Dye (6)

GSR/mt

Respectfully submitted,

GARY S. RASMUSSEN & ASSOCIATES, INC.

/;~/~ Gary S. Rasmussen Engineering Geologi.st, EG 925

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GARY 8. RASMUSSEN & .A.SSOC!A'I"ES


Robert W. Dye Proposed Commercial Building Site

Scale 1",.400' Project No. 1186

" .....


Zone covered by trenching, area shown to be free of active faulting

Gary S. Rasmussen & Associa es

Robert W. Dye Desert Hot Springs, California

Project No. 1186

Scale 1""2D'

Proposed Building Location

Property Line

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REFERENCES

Allen, C.R., 1957, San Andreas fault zone in San Gorgonio Pass, southern California: Geol. Soc. America Bull., v68, no. 3, p. 315-350.

Bennet, J.H., & Rodgers, D.A., 1975, Crustal movement investigations along the San Andreas fault in southern California, in Crowell, J.C., ed., 1975, San Andreas fault in southern California,""i" guide to San Andreas fault from Mexico to Carrizo Plain: Calif. Div. Mines & Geol. Special Report 118, p. 53-60.

California Department of Water Resources, 1964, Crustal strain and fault movement investigation, Bulletin 116-2.

Desert Hot Springs County Water District, 1976, Miscellaneous files.

Fairchild Carner~ September 29, 1939, Stereoscopic aerial photos, flight no. C-6060, photos 244, 246-251, 1"=1500'.

Hileman, J.A., Allen, C.R., and Nordquist, J.M., 1973, Seismicity of the southern California region, l Jan. 1932 to 31 Pee. 1972: Seismal. Lab. California Institute of Technology, Pasadena, California.

Jennings. C.W., 1975, Fault Map of California, California Division of Mines and Geology, 1:750,000.

Lamar, D.L., Merifield, P.M. and Proctor, R.J., 1973, Earthquake recurrence intervals on major faults in southern California, in Moran, D.E. and others, eds., 1973, Geology, seismicity and environmental impact: Assoc. Engineering Geologists, Spec. Pub., p. 265-276.

Proctor, R.J., 1968, Geology of the Desert Hot Springs-Upper Coachella Valley area, California: Calif. Div. Mines & Geol. Spec. Rpt. 94.

Richter, C.F., Allen, C.R., and Nordquist, J.M., 1958, The Desert Hot Springs earthquakes and their tectonic environment: Seismal. Soc. America Bulletin, p. 315-337.

Rogers, T.H., 1966, Geologic map of California, Olaf P. Jenkins edition, Santa Ana Sheet: California Division of Mines and Geology.

Schnabel, P.B., and Seed, H.B., 1973, Accelerations in rock for earthquakes in the western United States: Seismal. Soc. Amer. Bull., v63, no. 2, p. 501-516.

Tyley, S. J., 1974, Analog model study of the ground water basin of the Upper Coachella Valley, California: U.S.G.S. Water-supply Paper.;2027.

0.A.RY $. Fl.ASMU$Sl:!::N & ASSOCIA'rES

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Horizontal Scale 1"=10' Vertical Scale

Gary S. Rasmussen & Associates

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l//-sl2 · 3/31/1977 · 27595 sanla fe street hemet, california 92343 (7h) 658-7509 chy of desert...

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