STATE" OF CAlrFORNIA-THE f:IESOURCES AGENCY -e-· -- ··- O!;PARTMENT OF CONSERVATION DIVISION OF MINES AND GEOLOGY SAN FRANCISCO DISTRICT OFFICE FERRY BUILDING SAN FRANCISCO, CA 9.4111 (Phone 415-557-0633) County Engineer-Facilities Engineering Geology Section 550 South Vermont Avenue Room 403 A Los Angeles, California 90020 Attention: Art Keene Dear Art, •. .. George Deukmejian Gov•rrior We are placing on open file the following report, presumably reviewed and approved by the County of Los Angeles in compliance with the Alquist- !riolo Special Studies Zones Act: Geology report, Tax Parcel 3052-20-15, Lot 80, R,S. 64-32/35, Palmdale, CA; by lluena Engineers; June 2, l 981. report was received With out a cover letter or review documenting that it was reviewed. If it has, please send of this ·for our file. EWH:rys cc: A-P file Sincerely yours, EARL W. HART Office of the State Geologist CEG 935
18
Embed
DIVISION OF MINES AND GEOLOGY€¦ · 02/06/1981 · DIVISION OF MINES AND GEOLOGY SAN FRANCISCO DISTRICT OFFICE FERRY BUILDING SAN FRANCISCO, CA 9.4111 (Phone 415-557-0633) County
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
STATE" OF CAlrFORNIA-THE f:IESOURCES AGENCY -e-· -- ·-·~- ~ ··-
O!;PARTMENT OF CONSERVATION
DIVISION OF MINES AND GEOLOGY SAN FRANCISCO DISTRICT OFFICE FERRY BUILDING
SAN FRANCISCO, CA 9.4111 (Phone 415-557-0633)
County Engineer-Facilities Engineering Geology Section 550 South Vermont Avenue Room 403 A Los Angeles, California 90020
Attention: Art Keene
Dear Art,
•. .. George Deukmejian IN>XU1NIX.U::B.~X1t, Gov•rrior
We are placing on open file the following report, presumably reviewed and approved by the County of Los Angeles in compliance with the Alquist!riolo Special Studies Zones Act:
Geology report, Tax Parcel 3052-20-15, E~ Lot 80, R,S. 64-32/35, Palmdale, CA; by lluena Engineers; June 2, l 981.
report was received With out a cover letter or review documenting that it was reviewed. If it has, please send of this ·for our file.
EWH:rys
cc: A-P file
Sincerely yours,
EARL W. HART Office of the State Geologist CEG 935
IH1>1an approved geologically subject to conditions below
()iloSec. 309 Code requiromonts mot (o'"""'1rt) .............. 0 Sec. 308(bl 3c & e code requirements met (not met)
D Plan is not approved for reasons below
DSubmit plans for recheck
Remarks: i. DA consulting Oen.gincr.ring geology, L.Jsoils engineerir1g1 Oreportls) is required
_________ ,, __ ··-"'
2. ,,3A11 recommendatior~s of tha consulting design or shown as notes on the plans.
~eologist,
·-····-·· _, ... __ ... _,, ___________ _ Dsoils engineer rnus.t be incorporated in the
3_ DThe plan must b~ s.pccifically approved by the Dconsultant geologist, Dconsultant soils engineer by Dletter-report and/or Dmanual signature(s) with datc(sl prior to approval by the Geology Section.
4. O In-grading Inspections must be made by the consulting Ogeologist, D soils engineer. Dlnspection reports must br- submitted to the Geology Section for review monthly.
5. DRough grading must be approved by a approval by the Geology Section.
Ofinal geology report, L.Jfinal soils engineering report prior to DAn As-Built Geologic Map must be included in the final geology report.
6. ~oundation and/or wall e-xcavations must be inspected and approved by the consulting engineer, prior to the placing of $tcel or concrete.
~·geologist,
7. l..JThe County Engineer Soils Erigirieet·ing Section's Dapproval is required Orr-quirements attached
Dconditions of approval are attached Dapproval attached (dated--------······-·-.. -~ )
8. OShow all proposed tentativP. c,;orrcctive devices (e.g. buttress. stability fills, subdrains, etc) on the plan.
9. 0Add items .. -.,,-------- and ··~---------- , above-, as notes to the plan.
42326 ·10th STREET WEST • P.O. BOX 2866 • LANCASTER, CALIFORNIA 93534 • PHONE (805) 948-7538
June 2, 1981
Mr. Leo DeMonte 19449 Wells Drive Tarzana, CA 91356
Mr. DeMonte:
Subject: Geology Report Tax Parcel 3052-20-15 E~, Lot 80, R.S. 64-32/35 Palmdale, California
B-1860-LOl
Presented herewith is our Geology Report performed as authorized for Tax Parcel 3052-20-15, Palmdale, Los Angeles County, California.
Recommendations for general site development with respect to observed site geologic conditions are included. The conclusions and recommendations contained herein were based upon the applicable standards of our profession at the time this report was prepared. Copies are furnished only to provide the data which were gathered and which are summarized in the report,
Please contact the undersigned if there are any questions concerning this report or the recommendations in~luded herein.
Respectfully submitted,
BUENA ENGINEERS, INC.
~J!. Mark S. Spykerman Staff Geologist
Rw~~ ~hae1 v. 'mith
MSS/MVS/smn
cc: 6 - DeMonte 1 - file
ENGINEERING OFACES:
FIELO OFFICES:
VENTURA (805) 64U727
THOUSAN 0 OAKS (8051 49f>.8484
SANTA BARBARA 18051968-9912
R. G, #3273, E.G. #956
PALM SPRINGS (7141328-9131
LANCASTER (805) ..... 7538
SAN LUIS OBISPO (805) 5441-6187
I I I I I I I I I I I I I I I I I I I I I I
June 2, 1981 - 1 - B-1860-LOl
INTRODUCTION
In this report we present the results of a geology report for the
subject parcel in accordance with Section 308-311 of the Los
Angeles County Building Code, The study was conducted in accord
ance with authorization by Mr. Leo DeMonte on May 4, 1981, The
purpose of the study was to review fault and related geologic
hazards pertaining to proposed site development. Recommendations
are provided relative to the proposed construction of one single
family residence. Minimal site grading is anticipated.
The site geologic conditions were investigated in the field and
through selected technical publications. Conclusions regarding
the site are based on the data collected and form the basis for
the recommendations presented.
FIELD EXPLORATION
The site reconnaissance and field exploration for this project
was conducted on May 19, 1981. Field work consisted of the
excavation of one exploration trench approximately 300 feet in
length and extending from approximately five to six feet below
the existing ground surface. The approximate location of the
trench is shown on the Site Plan, Plate I. The trench was
excavated with a tractor mounted backhoe and was oriented
approximately perpendicular to the general trend of faulting
in the area. Portions of the walls and bottom of the trench
were cleaned of loose or smeared soil and graphic log compiled
illustrating the approximate locations and orientations of
pertinent features observed. The log is included as Plate II
of this report. Previous geologic mapping prepared by Barrows,
et. all (1976) was also utilized to aid in interpretation of
the site geology.
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
. June 2, 1981 - 2 - B-1860-LOl
The Site Plan, Plate I of this report was prepared utilizing
pace and compass measurements from existing street and topo
graphic features. The location of details shown on the Site
Plan, including the trench, contours, and drainage courses
should be considered accurate only to the degree implied by
the method used, The Site Plan is not a detailed site survey.
SITE DESCRIPTION
The + 1.2 acre parcel is located immediately south of Avenue
T-8 approximately 600 feet west of 37th Street East, Palmdale,
California. Access is from Avenue T-8 which is a graded dirt
road.
Topographically, the site slopes gently to the north except in
the northeast portion of the lot where the topography rises to
form a southerly trending ridge. Maximum relief is approximately
20 to 25 feet. Several intermittant drainage courses cross the
site approximately as shown on the Site Plan.
At the time of our field investigation, the site was vacant with
no improvements. Vegetation consisted of native weeds and
grasses with occasional junipers and joshua trees.
GEOLOGIC SETTING
The project site is located at the base of the San Gabriel Moun
tains in Southern California. The San Gabriels are a part of
the Transverse Ranges which
across Southern California.
extend in an east-west direction
Rocks
Ranges consist of extremely complex
composing the Transverse
folded and faulted rocks
varying from Pre-Cambrian gneisses to modern alluvial deposits.
North of the San Gabriel Mountains is a vast area of deserts
and mountain ranges comprising the Mojave Desert. Pre-Cambrian,
Paleozoic, and Mesozoic rocks overlain by extensive Cenozoic
lake and fluvial deposits are encountered in this area. Dividing
BUENA. ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
June 2, 1981 - 3 - B-1860-LOl
the Transverse Ranges from the Mojave Desert is the San Andreas • rift zone.
The San Andreas rift zone, which is up to 6,000 feet wide, domin
ates the landscape in the Palmdale area with classic fault features
and geologic structure. Right lateral offset of many streams and
gullies averaging 10 to 13 feet apparently records the most recent
fault movement along this portion of the main trace of the San
Andreas fault, which occured in 1857. Abundant smaller but· potent
ially active faults within the San Andreas rift zone lie north of
the main trace of the San Andreas fault. These include the Little
rock fault, Cemetery fault, and abundant subsidiary faults. Qllater
nary movement is locally evident along these faults.
SITE GEOLOGY
The site is located at the southern edge of the Mojave Desert at
the foot of the San Gabriel Mountains. The major geologic features
in this area is the San Andreas fault zone which is the result of
crustal plate interaction between the North American and Pacific
crustal plates. Movement within this zone is responsible for the
irregular topography and the deformation and faulting of lith
ologic units within the fault zone. Rock units encountered on
the site consist of Quaternary sediments, and Tertiary sedimentary
rocks. These include from oldest to youngest, the Anaverde Forma
tion, Nadeau Gravel, older alluvium, and Holocene alluvial deposits.
A description of the units encountered is as follows:
Anaverde Formation (Pliocene)
The Anaverde Formation consists of continental sediments
derived· from source areas located to the north. Due to
movements within the San Andreas fault zone, members of
the Anaverde Formation are typically folded and faulted
and contain abundant internal shears. Only the red arkose
member (Tar) is exposed in this parcel. This member con-
sists of tan to reddish tan, fine to medium grained arkose
which is poorly to moderately bedded, and severely weathered.
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
· June 2, 1981 - 4 - B-1860-LOl
On this parcel the red arkose member is in fault contact with
younger Quaternary sediments,
Nadeau Gravel (Pleistocene)
The Nadeau Gravel (Qn} is a continental deposit commonly less
than 25 feet thick, composed of poorly stratified reddish brown
to brown sand, sandy gravel, and cobbles. The unit at this
location is typically composed of unconsolidated to poorly
consolidated interbedded lenses of clayey fine to coarse sand
and gravelly sand, The predominate clast type is Pelona Schist
with minor quantities of quartz, gneiss, and granitic clasts.
Older Alluvium (Pleistocene)
The older alluvium (Qoa) consists of reddish brown to tan fine
to medium sand with minor gravel. The deposits appear to be
fine to medium sand with minor gravel. The deposits appear
to be less than ten feet thick and overlie the Anaverde red
arkose.
Holocene Alluvium
Holocene alluvium on the site consists of slope wash and coll
uvium (Qsw) and recent alluvium (Qal). Slopewash and colluvium
consist of unconsolidated sand and gravel transported downslope
by mass wasting and runoff. Recent alluvium consists of fluv
ial sand and gravel deposited in present day drainage channels,
FAULTS
The project is located within the San Andreas rift zone which includes
the San Andreas, Littlerock, Nadeau, and Cemetery fault zones. The
subject parcel is within the Littlerock fault zone, which in this
area is up to 1,000 feet wide. Additional faults within the general
vicinity of the site include, the San Andreas fault 1,300 feet south
of the site, the Nadeau fault 3,600 feet south of the site, and the
Cemetery fault 3,000 feet north of the site. All referenced distances
are approximate.
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
June 2, 1981 - 5 - B-1860-LOl
Results of the on-site trenching indicated that at least three
significant faults within the Littlerock fault zone cross the
site. Offset and disruption of Quaternary alluvial units
indicates that the faults are active or at least potentially
active.
Historically, the Palmdale area has experienced ground rupture
and severe ground shaking from moderate to great earthquakes
which have occured in the general vicinity. lntensity maps for
the past major earthquakes indicate the area experienced intens
ities as great as Vll to VIII based on the modified Mercalli
Scale. This assumption is in line with estimated intensities
felt during the 1857 Fort Te:jon Earthquake. Based on a hypothe
tical great earthquake centered near Littlerock, California (Gates,
1972), the Palmdale area could experience Modified Mercalli inten
sities as great as XI. A description of the damage which can be
anticipated based on the Modified Mercalli Scale is presented on
Table l of this report. It should be noted that the level of
damage predicted by the Modified Mercalli Scale is based on past
experience of a given earthquake on buildings not designed to
present building standards. Damage to structures designed to
current standards is expected to be less. However, possible
structural damage should be anticipated to structures constructed
within this area due to the potential for severe ground shaking.
other potential hazards include minor flooding and erosion within
the on-site intermittant drainage courses during peak periods of
rainfall. Potential damage due to flooding and erosion can be
mitigated by appropriate site grading during construction. Due
to the site location, generally moderate topography, and lith..,
ologic units encountered on-site, other geologic hazards including
landslides, settlement, and slippage are not expected to adversly
affect the site or the proposed improvements.
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
June 2, 1981 - 6 - B-1860-LOl
CONCLUSIONS
Based on the field reconnaissance, tr.enching, and literature
review, it is our professional opinion that the primary geologic
hazards relative to site development for residential purposes
are fault rupture, ground shaking, flooding, and erosion. No
obvious ground rupture or other evidence of recent ground move
ment was observed across the delineated "Building Area". Traces
of the Littlerock fault project through the property approximately
as shown on the Site Plan. In our opinion, construction within
the area designated as the "Buildable Area" should meet the mini
mum requirements of Section 311 of the Los Angeles County Building
Code. If construction for human habitation is intende:'!outside
the area designated, additional exploration should be required
to verify the absence of faulting at the additional building
location.
The site is located ~ithin the San Andreas rift zone. Therefore,
there is a potential for structural damage to any building in this
area due to severe ground shaking. It is our opinion that a sign
ificant seismic event and related effects resulting from move
ment within the San Andreas fault zone will occur in this area in
the lifetime of the proposed structure. Ground rupture would
most likely occur along previously established zoned of weaknessi
however, them is no guarantee that ground rupture will not occur
at other locations. Earthquake intensities as great as XI based
on the Modified Mercalli Intensity Scale should be anticipated
during severe seismic activity.
Possible flooding and erosion may occure in the vicinity of the
on-site drainage courses. Proper site management should mitigate
this potential hazard. As the .delineated "Buildable Area" is
relatively flat, sewage disposal by leachfield should not adversly
impact the slope stability of the site.
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
June 2, 1981 - 7 - B-1860-LOl
Based on the findings summarized in this report, it is our opinion
that the delineated "Buildable 11,rea" is not subject to a geologic
hazard from landslides, settlement, or slippage as defined in
Section 309 of the Los Angeles County Building Code. It is also
our opinion that the proposed building and anticipated site
grading will not affect the geologic stability of the site or
adjacent properties per Section 309, provided the recommendations
in this report are followed.
RECOMMENDATIONS
It is recommended that any on-site construction for human occup
ancy be confined to the area designated as the proposed building
location. Additional trenching should be required for construction
outside of this area. A 25 foot offset from projections of the
identfied faults is recommended.
Construction design should allow for all plumbing and utility
services to be connected with flexible connections and provided
with convenient shut-offs. It is recommended that residential
structures be designed to at least minimum code standards for
Seismic Zone 4 as designated by the latest edition of the Uniform
Building Code. Structural design should be reviewed for compli
ance with applicable seismic codes.
Grading Plans, if required, should be reviewed by the project
Engineering Geologist. All site grading should be in accord
ance with applicable building codes. Positive measures should
be taken to divert runoff away from the building site and other
future improvements.
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
June 2, 1981 - 8 - B-1860-LOl
LIMITATIONS AND UNIFORMITY OF CONDITIONS
The analysis and recommendations submitted in this report are based
in part upon the data obtained from one (1) exploration trench and
site reconnaissance. The nature and extent of variations beyond
the trench may not become evident until construction. If variations
then appear evident, it will be necessary to reevaluate the recom
mendations of this report.
In the event that any changes in the nature or location of the
building are planned, the conclusions and recommendations contained
in this report shall not be considered valid unless the changes
are reviewed and conclusions of this report modified or verified
in writing.
This report is issued with the understanding that it is the respon
sibility of the owner, or .of his representative to insure that the
information and recommendations contained herein are called to the
attention of the architect and engineers for the project and incorp
orated into the plan and that the necessary steps are taken to see
that the contractor and subcontractors carry out such recommendations
in the field.
The Engineering Geologist has prepared this report for the exclusive
use of the client and authorized agents. This report has been pre
pared in accordance with generally accepted engineering geology
practices. No other warranties either expressed or implied are
made as to the professional advice provided under the terms of
this agreement, and included in the report.
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
.. . .. ' . June 2, 1981 - 9 - B-1860-LOl
It is recommended that the engineering geologist be provided the
opportunity for a general review of site grading plans if required,
and site development during the site grading phase. (lf the eng
ineering geologist is not accorded the privilege of making bhis
recommended review, he can assume no responsibility for misinter
pretation of his recommendations.)
END o F T E X T
Appendixes
BUEMA EMGIMEERS, IMC.
I I I I I I I I I I I I I I I I I I I I I I
TABLE I
MODJFJEO MERCALU INTENSITY SCALE Of 1931' (1956 vcrsion>J
Mnonry A. B, C. 0. To avoid .ambiguily of language. the qu:dity uf masonry, brick ur ull1crwise, 15 specified by the following lcllcring.
Masonry A. Good workmanship, mortar, ;ind dnign; rc:inforced, especially laterally. and lmond lui;cll1cr by u>ing •led, cuncu:l1>, de.; designed lo rcsi~I lateral forces. ·
Mosonry B. Goud workmanship and morlar; reinforced, bul nol dc•igncd jq
delail lo resist falcral forc;es. · i1u)unry C. Ordiniilry '"ork1nans.hip and rnurl.ar; nu e.)l;lrc;rnc wcakncs.se:s like
failing lo lie in al comers, but ncilher rcinforo:cd nor desii:ncd ai:ainsl huri%onlal for· c:es.
Musonry D. Weak materials, such as adobe; pour mortar; low slandards of work· m"nd1ip; weak l1ori%unlally.
I. Noi hill. tw':iil.rgin.al and 1ong~po1iod clfcc.li or l4111go 1C.ilr'U1q""''-es.
II. feh b.)' per~ns at re,:t. on upper fktors. at f;mwt.abJy p~ced.
UL Fe-n indoor.sr H11nging <Jbjrcls. swing, Vibril1il):!'fl Uke p.a:.i.'!.og Of tight huck.$. Dur-11lion e51ima1o4. May not bo •acogni.ie-d aS. an t=arthquak• ..
- Vil. Difficule to slaltd'. NoUced by dtlYers or rnolor c•ff.. Hanging objeCl.S quiver. f\;rnilur• brok•n. Doam~ge lo n-i.a:i.onfJ D, lncluding ci•c~s. Wll!liD\ chimneys brok~n •t 1001 lin•+ f'all of pla51er. lo0:1ot9 ;,,ricli;s. stoOol!.$ 0 lilo.s. cotniceJ a•so :.:~.~ .. aced P•'~pols. and .-1chileclutal oui.:i.m•nts. Sorn• CfACks in "'""~nty C. Waves on pot'lids; w•1•r ti.Jrbid wilh ~ud:. SmaD slidtS1" And c•vi.ng In along sand or gr•'Hll banl5. Large bells fKra~ Conc1~1• lltiQ.aljaB dih:hes d ... maged.
VIII. Stporing or molor c.•~ .aUacted. 041.m•o• lo ~il.SORty C; P•nial eou:~p .... SQ.Me. dam.ge lo m•sonty 8; none lo ma1'0nN' A.. FaU of s•uc<:o •nd 1iOm• masonry w•Hs.. Twis.Ung. faU or chimnoys. l•cfott ~.ckst monumonts. ~cwcus. elevated lanka. fr ... m• hOl.i5ie.• moved on loundalions If "OI bollod do""": loon panel ••1ls lhrown out. Decayed pUing bl-ok•n orf. Bt ... nches broken from 11ees. Ch.ang•Ji lft f\Qw or tempat;;t.tLlt• of 5ptings and w•Us. Ct•Ckli in •e'l gtound •tad on 51.e•p slopes.
IX.. G•ner.-1 p•nic. Ma:1o1;1NJ' D de5tro,-.d: "'•50AIJ' C h••Yllt d•m•o..S. 50metimes wllh comp .... con.apse; rn•~ B li~rious1.y d•m•ged. G•n81.aJ dam•O• to loundalion... Fram. !Jtruc:lur•• .. If ftOI bOh.•d. s11iifled otf lou.,.d.•tion&.,. F'•me• t•ckedT Sefious d•m•g• lo ••MllrYQita. Undergn)Uf'ld pipa9. tcok•n.. Cons.picuoua c:t•t=k• in prouttd. Jn •Ptni••d .a19•s _..air.Cl arid mud ejected, iear1hquak• lovft-. tain•. Nnd cralera..
x.. MO$l m:11ti0nl)" and h•me 51JU"dU:••• de1.troy•d 'With lhcllr lound111ions+ Som• weH~~lrt woodon s;:ltUC-1u1e1 a"d bridge• dt11s.llV}'•d.. Seriou .. damag• 10 darns. dila;•s. •rnbank"'9nt•. Large landslides.. W•••r thtown on b.nks or ca11.1lt. riv.rs. l•k•s. el..e. Sand ar"d mud s.hltl•d horizontally o" be•che• and flat land. A•Hs a>.nl aligh11J'.
XI. fl•lb llient o•••t'1. Underground pipeline-a compla1ely out .,, sef'Vic:•.
XII. Da.mao• noarJ;r l(Jl•l Lll•g• rock rna~s displ ... ced. Une• al sipht and lev91 di•lot1"'1. Ot>jecto th1owt1 Jnlo •hi• •1'.
•O.ig""aJ 1911 "'•rsi6tt .,_Wood. H. 0,. Ahd H11n11ft.,,,n. f' .. 1f31. Mo.difi•d MP~fk lnt•~•llr uat. ol l~.lt; S•J~n.OloJikM ~r.•1 o1 ...,,..,~ .. ,...,,,.,M. .... !.l... •- L ._. •n.111.
~19.56 ••si.:in p;itrpar.cf bJ" Ch&l'J.n f. R.idt.,et., 1111 CNtrt~a.ty S•i .. "'°lo'lll'· 19.s.I. pT 13J ... t3',, W .. H.,. F1e9tniflll A C::-..
Source: California Division of Mines ~nd Geology, 1975, Special Report 107.
I I I I I I I I I I I I I I I I I I I I I I
June 2, 1981 B-1860-LOl
"
REFERENCES
1) Barrows, A.G., Kahle, J,E., and Beeby, D,J., 1976, Geology and Fault Activity of the Palmdale Segment of the San Andreas Fault Zone, Los Angeles County, California, CDMG Open File Report 76-6 LA.
2) California Division of Mines and Geology, 1969 1 Geologic Map of California, Los Angeles Sheet.
3) , 1975, California Geologic Data Map Series, Map No. 1, Faults, Volcanoes, Thermal Springs and wells.
4) , 1977, Fault Hazard Zones In California, S.P. 42, Revised January 1977.
5) , 1977, Active Fault Mapping and Evaluation Program, S.P. 47.
6) , 1979, State of California Special Studies Zone, Palmdale Quadrangle.
7) Dibblee, Thomas w., Jr., 1967 A.real Geology of the Western Mojave Desert, California, U.S. Geological Survey Professional Paper 522.
8) Gates, G.E., 1972, The San Fernando Earthquake of February 9, 1971 and Public policy, Special Subcommittee of the Joint Committee on Seismic Safety, California Legislature, July 1972.
9) Kahle, J.E·., Smith, D.P., and Beeby, D.J., 1975, Geology of the Leona Valley Segment of the San Andreas Fault Zone, Los Angeles County, California, CDMG Open File Report 77-1 LA.
10) Noble, Levi F., 1953, Geology of the Pearland Quadrangle, California, U.S., Geological Survey, Geologic Quadrangle Map of the United States.
11) Sieh, Kerry E., 1978, Earthquake Intervals, San Andreas Fault, Palmdale, California, California Geology, June 1978.
•
BUENA ENGINEERS, INC.
I I I I I I I I I I I I I I I I I I I I I I
---------..-----------------------------------------------------------------------------------.... North
W 1 - Bru.n silty sand with C)ravel and =bbles. V=rriably cerrented.
Qll-2 - Greenish brown fine to coarse sand with gravels and =!::bles, poorly bedded. J:oose to rredium dense.
Qsw - South of rrain drainage: liqllt reddish brown to brown silty fine to mediun sand. Itxlse to rredium dense North of rrain drainage: ~clayey fine to !'Edi.um sand.
Qoa - BrcMrl to light reddish tan silty fine to !Tedium sand with minor gra~l. Poorly b:>dded. MediU!l dense to dense.
lt!.deau Gravel
W - Dark reddish brown fine to rredium sand with clay. Abundant quartz float.
Ob! - Reddish brown clayey fine to rredi un sand with gravels and col::fil.es. cerented, very dense. Zone of illuviaticn.
()1-3 - Dark brown silty to slightly silty fine to coarse sand with gravel and =bbles. 't::derately bedded. I.oose to dense.