STATE OF CALIFORNIA-Tt-tf RESOURCES AGENCY Jtf I fl 7 ?GEORGE DEUKMEJIAN, ""-'

DEPARTMENT OF COf',ISERVAtlON

DIVISION OF MINES AND GEOLOGY BAY AREA REGIONAL OFFICE 380 CIVIC DRIVE, SUITE 100 PlEA~ANT Hll~ CA 9'523-1997 PHONEo (41'1 671 .. 920

Mr. John c. Bowman, CEG 317 county of San Bernardino Environmental Public Works Agency Land Management Department 385 N. Arrowhead Avenue San Bernardino, CA 92415

Dear Mr. Bowman:

February 19, 1986

We are placing on open file the following 11 reports, reviewed and approved by the County of San Bernardino in compliance with the Alquist-Priolo Special Studies zones Act:

l. Geologic/seismic investigation of portion of 8.97-acre parcel, NE corner of Carson St. and Norton Ave., SW 1/4 of SE 1/4 sec. 20, T. ls., R. lW., Yucaipa, CA; by G.A, Clopine; January 4, 1985,

2. Fault investigation, proposed dormitory facility, Camp Yolijwa, 39136 Harris Road, Oak Glen, CA; by Aragon Geotechnical Consultants; August 9 1 19841 with supplement of August 22, 1985.

J. Geologic/seismic investigation of portion of 3.713-acre parcel on Pine Hench Road, oak Glen, CA; by G.A, Clopine; September 3, 1985,

4. Fault investigation, lot spilt-single familt residence, 35467 Ivy Avenue, Yucaipa, CA; by Pioneer Consultants; March 22, 1985,

5. Engineering geology investigation of 4 Road, portion of NW 1/4 of NW 1/4 sec. 16 1

CA; by Rasmussen & Assoc.1 July 23, 1984. is missing.

acres NE of Torrey Pines T. ls., R lE., Forest Palls, Enclosure 4 (embankment log)

6. Geologic hazards report, portion of Lot 7 1 south Mountain Subdivision, Oak Glen, CA; by Craig Smith; March 21 1 1984; with supplements of May 15 and July 23, 1985.

7. Engineering geology investigation, Palm Terrace Mobil Estates development, Lots 1-111, portion of N 1/2 of SE 1/4 sec. 22 1 T. ls., R. 4E., Morongo Valley, CA; by Rasmussen & Assoc.; May 10, 1979; with addedum of March 25, 1983 and December 4, 1984. Plate l (parcel map) and portion of Enclosure 3 (Trench logs 1 and 2 incomplete) are missing.

8. Fault investigation, single residence, Deercrest Drive and Foothill Street, Devore are, CA; by Leighton and Assoc.; Sept. 24, 1984; with supplement of January 23, 1985. Plate l (site map) and App• A & B (logs to trenches lA, lB, and 2) are missin~.

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Mr. John c. Bowman February 19, 1986 Page -2-Certified Engineering Geologist

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9. Subsurface engineering geology investigation, 1-acre Yucaipa Blvd. & Oak Glen Road, Yucaipa, CA; by Rasmussen June 19, 1985.

lot, & Assoc.:

10. Site investigation, 1144 Deercrest Drive, Devore, CA: by Geological Systems Evaluation Corp.; August 9, 1985; with addendum of November 5, 1985.

11. Geologic/seismic report, minor subdivision 83-0215, 5-acre parcel, SE corner Ivy Avenue at Fremont Street, Yucaipa, CA: by G.A. Clopine; November 25, 1985.

Please note that illustrations essential to reports 5, 7, and B above are missing. These should be submitted to complete our file.

Also, note that the trench log to report 11 shows an abrupt change in topography (scarp?) at 345 feet that coincides whith a sharp warp in the underlying soil and alluvium. This anomalous feature is not discussed, nor was it investigated further. Features such as this are often associated with faulting and should be addressed in the report. Theses comments are not intended to cause additional investigation but are provided only as suggestions for future reviewing.

In response to your letter of February 7, 1986 1 the above reports, which were sent to Sacramento, eventiallY were forwarded to me. Regarding the review of reports, we ask all cities and counties to document their reviews. However, it is not essential that all correspondence be submitted for our files, and the method of documentation is left to your discretion.

Good luck in your new job. tet me know if you have any questions.

EWH:fnm 1480A

cc: A-P file (11)

Sincerely,

Earl w. Hart, CEG 935 senior Geologist &

Program Manager

i>:F.N"'iF.Tll C. TOPPING ~puly AW~1i1li8lHllOr

D~vidup1~1Cill ~ervi~!

ENVIRONMENTAL PUBLIC WORl{S AGENCY

LAND MANAGEMENT DEPARTMENT

JOHN N. JAQUESS Ll.iid Mannsement Dirl'"l:lOI"

385 N. ArrowJic-ad Avenue, San Hcrn!:l.rdino, CA 92415

OF'FlCJ: OF PLANNING Coonly Pl~nnin@: Offo:u

OFFICJ::: OP SURVEYOK Claude n. Tl'.lmli11~011, L.:'\.

County St1rv~yor

January 16., 198G Ofl·'IC:F. or DUILDJN(i AND SAFETY

r .nrry L Schoclkopf. P.E Ct)Unly B11lldlns Offid;:il

State Geologist California Division of Mines and Geology P.O. Box 2980 Sacramento, CA 95812

SUBJECT' Submittal of geologic report for project located within a special studies zone, San Bernardino County, California

1. In compliance with the policies of the State Mining and Geo­logy Board, please fine enclosed one copy of geologic report entitled,

GEOLOGIC/SEISMIC REPORT, MINOR BUEDIVISION, A FIVE ACRE PARCEL SOUTHEAST CORNER IVY AVE. AT FREMONT ST., YUCAPIA, SAN BERNARDINO COUNTY, CA

DlVI'ED: ll-25-8S

2 . This project, identified falls within the special by your office.

0086 by San Bernardino County as LG studies zones as presently identified

Sincerely,

John . Bowman, Jr. Certi ied Engineering Geol gist Department of Building & Safety EPWA/Land Management Department

JCB/jlo

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TELEPHOMC 11141 194-6700

/ '·GORDON A. CLOPINE • RE~ISTERJ?!! GEOLOGIST CLOPINE GEOLOGICAi. SERVICES

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===========~========:=========== ==o:=====--============ f:ERTIFlED PROFESSIONAL GEOLOGICAL SCIENTIST

RESIDENCE AND OFFICE' !3093 llURNS LANE

REDLANDS, CALIFORNIA 92373

m TITLE: GEDUXllC~ REPORl', MnDR SUBDIVISION t!J 6215,

A FIVE .ACRE PAOCEL SU1l'HEAST OOltiER !.VY AVENUE AT FREMNl' SI'REE't, YU::AJPA, 51\N BERNARDINJ CCllNl'Y, CA.

lll\'l'E: N:lllEMBER 25, 1985

PREPARED FOR: CAMILLE llURKllART 35534 B.l\LSA st.KEE'!' YOCAlPA, C1\LIFORNIA 92399

PREPARJ;D BY: ~A. CIDPINE RmlSlERUJ GFDIOOIST l'D. 511 STATE CF CALIFOmttA

CE!kl'IJ!'IED ProFESSIOOl\L GF.OI.OOICAL SCIEl'll'IST m. 6125 N£RICAN INSTrruTE CE PIO'ESS:raw.. rnISl'S

GOr::f'CN A. CL(.1:·:;::-~1;~E

No. 511 *

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November 25, 1985

TABLE

GORDON A.. CLOl'INl: t:i~•Q't.~11> a:11g.111~P Wfg.x.O~in

imDL.6.NDB, O.&.LIJl'ORNU. ll'il:.73

OF CONTENTS

GFDTCG!C/SEISMIC REl-ORr, MIWR SUBDIVISION 83-0215, A FIVE ACRE PAOCEL SUJTltE7IST CORNER W'i AVENUE AT FRDOll' STREET, YOCAIPA, SAN BERNARDIN'.> CXllNl".l, CALIFORNIA

Topic Page Nuniler

I • lN'l'KlXX:Tictl IJ;icaticm and Description of Property 1 Map 11: U>caticm of Subject Property, with Alquist-

Priolo Special Studies Zone Bou!xlaries/Faults 2 Puxp:>se of Report, slopes, vegetaticm, survey 3

II, 'nm INVES'l'IGM'Ictl

le;Jional PsviElw and seisznic setting Map 12: Earthquake Epicent& Map Methais of Study Seisnic ccmsiderations and Analysis

Earthquake RecurrenQe InterVals Ml!xiJlun credihle F.arth:Juake Mi3ldltun Pmbable F.ax'thquake Mi3ldltun (peak) Rock Acoeleration Repeatable High Grourxl 1\coeleraticms Duraticn of Gramd Shakinq Period of Bedrock J\cceleraticn

III. RESULTS CF lmlDY AND srm GEXlTOOY

Rock '.fypes - Discussicn Ulcal structural Setting Geokigic Trenching stu:l:y and Ana1ysis Drainage and GroUl¥iwater

r.v. a::N:WSIONS AND ~

4 6 7 8 8 9 9 9

10 10 10

11 12 13 14

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E!CUlSURE fl: SITE DEVELOPMENT MAP 21 GEXXOOIC MAP 21 '1'leDI ID:ATlW WIP 21

aa.ostlRE 12: TRFN:H IOOS CF THIS INVESTIGA.T!ctl (4 Sheets) 22-25 APPlHllX A: PICMlNEm' FJ\R'nOJ1\I<ES IN~ 26 APPEN:>IX B: MDIFIED MJ;a:ALLI AND RICHTER MAGNl'lWE 27 APPmllX C: FAULT-RUPruRE llAZAflD Z<NES IN CALIFORNIA 28 APPENDIX D: AUJJIST-PRIOID REUJDUH;Nl'S, SAN BERNARDIN'.> COON'l'lr 33

GORDON A. CLOPINE • REGISTERED GEOLOGIST CLOPINE GEOLOGICAL SERVICES

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CERTIFIED PROFESSIONAL GEOLOGICAL SCIENTIST

RESIDENCE AND OFFICE,

13093 BURNS LANE REDtANDS, CAUF()RNIA

~ 25, 1985

Camille Burkhart 35534 Balsa Street YUeaipa., california 92399

Dear Ms. Burkhart:

92373

GEnIJ:GIC/SEIS"IIC REPORT, M!OOR StJBOIVISIOO 83-0215, A FIVE-1\CRE PAOCE:L, scxmtE:AS'l' CDRNER r.rt AvmtlE Nr FREMNl' S'l'REET, YUCAIPA, SAN BERNAROIID O'.XlN'lY, CALIFORNIA.

At your request, I have conducted a geologic/seismic investigation of the above described parcel.

I. INl'lnXx:l'ION

The property described in this report consists of a rectangularly shaped p;u:cel of 4.5 acres +, 330 feet (east--wst) by 660.62 feet (north-south), in the nort:ll'i>'est =rMr of the southeast quarter of Section 19, 'l'OWnship l N::>rth, Range 1 !\est, s.B.B.& M., at the corner of Ivy Avenue and Frerront street, Yucaipa, san Bernardino county, California. The northwest property . ccn:ner is the center of section 19.

The property is shown as Assessor• s pa.reel nimtier 5, on page 21, book 320, Assessor's !Mp, San Bernanli.no County, califomia. Assessor• s parcel nmtier 320-211-05, Latitude of the parcel is 34° 4' 10" ti::lrth, and the longitude is U7° l' 30" ~st.

h::cess to the property is fran Ivy Avenile, an inproved paved road, or fran Frerai.t Street, an unirrproved gravel ro;id, east of Bryant Street, Yucaipa, CA., as shcMn on Map #1, page 2 of this report. ·

All of the subject property is located in an Alquist-Priolo Special Stwies Zone, and provisions of the llct apply. See Map #1, page 2 of this rei:ort, for Alquist-Priolo boundaries and information,

Elevations on the property range fran approximately 3060 feet to 3040 feet, gently sloping to the southwest to Live Qak Canyon-san Tim>t.eo drainage basin. Slopes en the property range fran 5° to 1°, with an average slope of :P.

Page l of 36

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GORDO"! A. OLOPINE f;IOJJBULTDfO llLilQ.J: .. 'nDQj:iJ ~~(l(Hft

REDL.l..NlH.11. OA.LJ:l"ORN'.t.6. 028173

Map lll. I.Dcation of Subject Property, shown in yellCM, at the center of sectiai

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19, T 1 N, R 1 w, S.B.a. & M., san Bernardino County, california. 'Ibis rrap a p:>rticn of the Yucaipa Quadrangle, u.s.G.s., 1967, photorevised 1980. Scale: 1:24,ooo, North t.o top of page. aowidaries of Alquist-Priolo Special Stwies Zone, with faults as indicated on the Official Map also shc:Mn.

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GORPON A.. CLOPINE l;JQJlll".'Q"LTDICll Jl..lli)l!ll~ OBOLOGl.'Z'

mt.l)i..&.Nt>&, C.U.lFORNl• 9:2&'73

Nove'ttJer 25, 1985 Page 3 of 36

It is my W'rlerstanding that the property is planned for minor subdivision to four (4) parcels, as shown on Map 3, a part of this report.

A single-family residence and garage, built in the early l900's, exists on Parcel 1 in the ~st :region, at 35705 Ivy Street. Several outbuildings f= horses, storage, and sheep exist on Parcel 2. Parcels 3 and 4 are .horse pasture with no ~ts or structures.

The purpose of this investigation was to investigate all geologic/seisnic aspects of Parcels 2,3, and 4, as sham on Map 3 of this :repoi:t, according to provisions of the Alquist-Priolo Special Studies Zones Act, and in amfm:mance with policy and geologic procedures identified by the c.ounty of San Bernardino as Land ManagEmi!nt Standard Pti •::elnre and Policy:Geologic Fault Hazard Study Requirerrent, dated lt>Velb!r 8, 1984, This docunent is inclmed in this report as Appendix D for your information.

A ma.in zone of faulting-associated with the south branch of the San Andreas fault zone exists appzoKiJtat.ely 1600 feet north of the north property line of the subject property, A fault identified as the oak Glen fault (see Map fl, this tep:>rt) is adjacent and southeast of the property, Several faults not shown on the Alquist-Priolo map were identified as a part of this study locat.ed appmldmately 380 feet south of the subject parcel.

'lhe regiautl strike of faults north of the subject property is North SS° westi the :regional strike of faults southeast and south of the subject property is North 750 west to approxilllat.ely North 85° 'lo>est. 'lhese :regional fault trends were used \\1hen planning the location of the backhoe excavation oon:1uct.ed as a part of this study,

A faUl.t ~tified as the "Tucker FaultH by Snith and Seff (1984) may 1:rem l'k>rth 40 Eaat following a drainage adjacent to and east of the southeast prnperty corner.

'lhe principal c.nicern addressed during this investigation was to deteJ:mine if splay faults assoc:iat.ed with any or all fault zones of the area were located m the subject property to determine the suitability of the proposed parcels f= devel.op:lient with structures fOt' hunan cx:cupancy. All geologic/sei!Kllic considerations and discussions, including all conclusions and :i:ecu11re11dations of this :i:ep:u: t, hoWever, are inqxlrtant topics for current f)l:ope:t ty owners, future prqierty owners, and all developers and engineers that may be involved with future inprovenents.

survey of the subject property was tied to existing survey lll:lnl.alents on the aubject property: at the northwest property crn:ner (center of Sect::kwl 19) which is the center of the intersection of Ivy Avenue and Fretont Street, identified by R.c.E. 18591 with a survey 1101unent; and 330.00 feet east of this locatim in Ivy Avenue at the northeast Pl"oi:et ty comer. (existing survey

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Burkhart

GORDON A. CLOPINE (lQ:if•111amo Jl:.QIST.DUID OmoLOQUT

rum:t..A.ND8, OAlJ.J'ORNU. 9.11;1"18

November 25, 1985 Pase 4 of 36

nail) • 'niese existing survey l!Dnuments are shown on Map 3 of this xep:n: t. 'lhe precise location of the backhoe trench of this investigatim. was tied to these existing 11tt1uments, and is shown on the Site Oevelopnent Map for this project, Map f3 of this report. Distance was neasured by neans of fiberglass tape and measuring \>heel, and carpass directicns 1o1ere taken by rreans of a tripcxi rrountEd Bruntm caipass.

A 100-scale rnap, pxovided by Ric:haLd P. Si.eg:ruM, Licensed Land SUrveyor, of Sigl.aOO and Asscx::iates, 364 Orange Show Lane, san Bernardino, Califomia 92408 was also utilized during this i.nvestigatiai, No detailed topographic l!Bp of the property is available, and no grading plans have been prepared.

No native vegetatim exists on the subject property, with the possible exceptim of occasia\al -1.s. Landscape shrubs and trees with lawn is present arcuni the existing residenoe m Parcel 1, and saie plantings occur a.round the outbuildings m Parcels 1 and 2 in the northem me-half of the subject property. Five rnature ~ trees are shown ai Map 3 of this report,

All portims of Pan:els 2, 3, and 4, as shoWn en Map 13 of this report are described in this report, with the exceptiai of the exlLe!e eouthwest comer of Parcel 4 and the extn!le northeast comer of Pan:el 2, which were beyaJd the limits of subsurface trench evaluatiai, '!1lese.two small triangular oorners are identified in yell.ow on Map 113.

rn o::mformanoe with policy of san Bemardioo county Land Management Ilepart:mmt guidelines, califomia Divisiai of Mines and Geology Note Nlmtlers 37, 43, 44, 46, 48, and 49 were utilized during this study. (See References, this repoi:t).

II. THE INYESTIQ\Tlrn

A, !legional Review and Seismic Setting

'lhe northeastern Yucaipa valley lies within a very cmplex geological setting at the boondary of the Peninsular Range geamLphic province and the Transverse Range <JeCtlotpJ.c province. 'lbe san Andreas fmllt :i:one is man-el in this area as a north branch, 2.75 miles north of the subject pr:operty1 and a southern branch, 1600 feet north of the subject property. (Dihl.ee, 1982b). Splay faulting ~iated with the san 'Andreas fault is very camai. - exanples would be the Oak Glen fmllt and the "TUcker fault", described above, Further, the Chicken Hill fault is me mile southwest of the subject property. (See rnaptl).

NureLws ground water barriers, such as the SOUth l't:!sa barrier, casa Blanca biurier, and the Yucaipa barrier are present in the Yucaipa Valley. Qot>xel.aOO, 1970)

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Burkhart

GORDON A. CI.OPINE i;Qllr.UL'.l'DfO _.Ql8nntZD QSOLOdfH

REDL.4.NDlt, C.ALll'ORNU 9281f8

Nove'llber 25, 1985 Page 5 of 36

No significant earthquake epicenters are known to have been located along the faults or ground water barriers listed above during historic time (the last 200 years). Map #2, page 6 of this report, locates significant epicenters in southern california during the period 1900-1974 (Real, 'l.q'lpozada and Parke, 1978). Highlighted on Map #2 are the epicenters within a 25 mile radius. Three 6.0 (Richter rragnit.u:1el or greater earth:}uakes are within the 25 mile distance: Cll September 20, 1907, Richter magnit.u:1e 6.0, near Running Springs :in the San Bernardino Mountains; (2) April 21, 1918, Richter magnitWe 6.8, in the san Jacinto-HEll'et area,: and C3l July 23, 1923, Richter magnit.u:le 6.2 in western San Tiln:>t:eo canym, south of Iana Linda. Updates to the map prepared by Real, 'lbppozada and Parke, 1978, have been published in California Geolcm', July 1979 and April 1985 (See Referenoeel l No additional 6.o Ricllter magnitude earthquakes have taken place within the 25 mile radius since 1974.

'Ihirty miles east of the subject~. at Desert Hot Springs, a 6.5 magnitude event occurred in 1948 on Decertier 4. A mmtier of srna~ earttq.iakes have occurred ai the SM J\ndreas near Barming, but na1e larger than 5. 0 Richter magnit.u:1e have taken plaoe si.noo 1932. \'lest of the Sllhject p.coperty, the great Fort Tejc:n earthquake of 1857 (Richter magnitme 8?) caused surface disruption into Cajon Pass and possil>ly into the San Bernardino valley to Waternan canyon (?). Wat:el'nlM eanyai is located 15 miles~ of the subject property •

The San Jacinto fault is located 10 miles soutmest of the subject property ana nmerous ~of Richter magnit.u:le 4.0 to 5.5 have occurred during historic tine in the San Bernardino valley. Damaging earthquakes ~ in 1899, 1918, 1923, and 1968 along the San Jacinto fault. The san Jacinto fault is generally ao::ept:ed as the nr:ist active fault in southern California (Sharp, 1967), the rtDst recent activity at Oct:oher 2, 1985 at the aaJne epicenter aa the July 23, 1923 earth:!Uake listed alxl\re.

A SU!fllarY list of inp:>rtant eart:!xJuakes fran a regional viewp:>int would inclu:le the events of 1857, 1899, 1907, 1918, 1923, 1940, 1952, 1968, and 1971. see AppendiJ( A, this report, for a sumnary list of :inp:lrtant earthquakes. 'lhls AweildiJ<: A alao inclu:les a listing fm: t-biifie3 Mercalli intensity and Richter ln3gllitude, for llDBt significant earthquakes during the tirne period COlle1'91.

~ B, this report, provides a descriptkn of IUU.fied Mercalli intensity designatic:ns, and a carparison with Richter magnitude. Richter magnitude is a ~ of the energy released during an event at its source (the focus). foblified Mercalli intensity, on the other hand, is a subjective neasure mi.ch depends ai the effects of an eart1¥JUake on life and property in a regiai during and inm:ldiately aft& an event :In the vicinity of the regiai directly above the focus (the epicenter). 'lbus, Riehter magnitude and M::ldifi.Erl Mercalli intensity are ~le to relate precisely, but Appendix B does give the awroxiJnated relationship for a populated area Ilea)'. the epicenter •

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\ \ \\ '' \ \ ~~' '~,,, 'r \, '\~ ,\ I .... , .. \

' ' ' \I '~ \. \\ \ \ \ '\ \ \ 1\ \ \ \ \\\, \

GORDON A. OLOP!Nl!: COJll'9~Ci .. GmTIARll~ OJl:l)~(IG ......

JtEDL.&.NJ)ll, 0.ALIFOHHLA.. tt2&1t'B

Richter Ma~t\¥'le ~ ............. D TO 4.9

Q) ............ 5.0 TO 5.9 C) ............ 6.0 TO 6.9 Fault

C) .......... 7.0 TO 7.9 ____ ___...........

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Scale: l : 1000000 l" = 15. 78 Miles

5 Maxinurn Reported Intensity (Prior to 1930'sl

Map t 2. EartJxtuake Epioanter Map of Vicinity of SUbject Property in Southern california. Base Map f:i:an Real, ~zada, and Parke, 1978. Epicenters of earthquakes shcMn fran 1900 to 1974.

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GORllON I>.. CLOPI!a (IQQ~OUO~~

1lBDlilm8. O.A.ld1'0RNU. 811. ,..

Page 7 of 36 Na\rellber 25, 1985

A nuttier of other faults exist within a 5o-ile radius of the subject property (Jenning&, 1973), haweller, the 5an AMreas (and xelated splay faults), the San Jacinto, and the Co:analga-Sie?ra Madre fault zones are the ncst significant faults for seismic ccnsirleratians at the subject site. '!he other, to this date less significant faults near the subject property are the Chicken Hill and Elsinoze faults.

B. M:!thods Of stu.fy

'!he geology of sauthern cal.iforni.a has been the subject of direct and intensive field study and research by the author since 1961. As a part of this investigation, plblished references and persaial field notes and neps describing regialal and local geology ~t to site qeologyl 'Wli!rli! reviewed. 'lhese materials are listed under Neferences, a part of this teporL. In addition, the fol.lcWing took place:

1. Visited the subject property in the carpany Of camille Burkhart a'I October 10, 1985.

2. o::n:luct.ed prelimi.Nu:y smvey of the site and vicinity ai October 11, 1985.

• 3. Written authorizatian to ccniuct this study was received Noventier 6, 1985.

4. Geologic field st:udy was ccniucted Novenber 7, 9, and 11, 1985 of the subject site and vicinity.

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S. ca Nol/Ultier 14, 15, and 16, geologic field stlily was Catducted at the subject property including five hundred and thtee (503) feet of subsurface tw::kme mvatian. T.cench location is shown ai Map fl of this tepotL. Trench excavatia'IB wei:e geologically evaluated and logged perecnall.y accmding to 8taOOaid geologic practice CTayw and Cluff, 1973). Trench logs are incluied as a part of this :reµn:L, ccnsisting of 4 sheets. Backhoe operat.or was Mr. Steve 1't::IntyJ:e of BOb Britten, Inc. Also pI sent:ai-sit.e wete CMd.11.e Burkhart and Jim Burkhart.

6. 'lbis investigatiai Wa/il Catducted in close cooperatian and coordinatian with Mr. Richard P. Siegnun:l of Siql.arxl and AsllOCiates, Surveying and Land Developnent, 384 Orange Sh::Jw Lane, San Bematdino, CA. 92408.

7. Duril'lq the course of this investigatian, aerial ~ of the subject site and vicinity were stiilied and evaluated. ~ are identified as 10-16-59, AXL-17W-131 and 10-16-59 AXL-17W-1321 also san Bemardino O::Junty Flood o:ntrol 10-8-71, nmtiers 30 and 31.

8. Review of all a:wilahle reports, aerial photograpui, peraaial field mtes, maps, and other references, listed as a part of this report, was caipl.eted prior to the preparatioo of this 1epcn:t.

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GORDON .A.. CJ.Ol'INE eo.-.~a, -~ OlllOl.OOl9'2'

HEDL&lrID8 0 o..u.nroBN.I.&. 9111t'I

NcvaliJer 25, 1985 Page 8 of 36

c. Seisnic caisideratims and Analysis

As described in Fault...flazani Zonea in califomia, by Hart (1976, 1980), the Alquist-Priolo Special Stull.es Zonea Act was signed into law ai DecaWer 22, 1972, a.rd has been aJOOl1ded four times. '!he pttpOSe of the Act is to prohibit the loeatiai of llOSt atructures for hunan oocupancy acmss the traoe of an active fault, a.rd to mitigate thereby the hazard of fault-rupture.

Faults aloog 1Jlhich l11J11818lt has occurred during the last 11,000 years are defined as 1CrIVE by policies and criteria of the State Mining and Geology Board. These lt:ilocene a.rd Histoi:ic active faults are cmsidered to be the faults nDSt likely to have :r:eneued l!DllS'l'te!lt during the life of pmpoeed st:r:IEt:ures at a subject site, and llDl!lt likely for surface rupture. Faults are defined as l'Ol'ENl'IAt.LY 1lCTlVE if they sh::Jw evidence of surface displaoenent during the Quaterna:r:y Pe:r:iod (the last 2 to 3 milliai yea:r:s) • 11f¥topr.i.ate infmmatiai fran Hart (1980) ia included in this report as~ c.

I consider it very likely that significant ea:r:tb:J1Wres will occur alaig the ~ J\Mreas or othe:r: faults in southern california during the lifet.iJle of

- pt• , c sed structures at the subject property. It is very :lnpartant that all pe:r:8CNI involved with future developnent at the subject site ba::aue familiar with the described geological ccnditiais at the site, in order that they might pe:r:saially determine if the levels of qeologic :risk at the subject site a:r:e within thei:r: levels of allowable :risk for thei:r: life and property.

1. ~ Recurrence Intervals

The earthquake recurrEnCe intervals for the San .And:r:eas, San Jacinto, and Sierra Madre fault zaies are giVli!fl by Lllrna:r:, Merifeld and P.toclor, in Moran and othe:r:s (1973, p. 267) as;

Nalle of Fault:

southern San Am:r:eas San Jacinto Sierra Madre

Recun:ence Intervals at a point ai the fault Richter l'IBgJli ti.lie:

6 7 8

Recun:'ence r.ntervals O\leJ'.' the length of the fault Richter JMgnitude 6 7 8

10 40 200 .3-1 3-10 40-100 400-1000

800 100 400 2000 4-10 4-100 100 300 800 30-100 100-300

RE:VRREN::E mI'ER'JALS GIVEN IN YEARS

'!he above figures clea:r:ly Wi.ca'te that a Richter magnitude ~·of '6.o or greater is past due on the soothem San _Andreas fault •

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GORDON A.. OLOPINJC COQID.TDl"G .. ~ ~

RBDLA.HD• • O.&Ul'OIDiU. 88&1f8

November 25, 1985 Page 9 of 36

2. MaxiJIU1l Credible Earthquake

'JhellWCinun credible~. as given in this zepotL, is defined as the believable mrudnun ~ capable of OCCULri.ng in the vicinity oi' the subject property, o::wisiderinq the local and zeqimal tectooic frmnework. (calii'ornia Division of Mines and. Geology lbte NlmtJer 43, Februazy, 1975);

Nmne of Fault 1aie

a.5 7.5 6.5 7.5

F.llrthquakes in the abcYe Richter nagnitmes lllDIJld be oonsidered SEITERE.

3. Maxinun l'Lt:i>!lble Earthquake

'lbe muinun probable eartlquake, as given in this zeµat, is define! as the IMXinun earthquake that appean; to be reaaa\able and expectable within any 100 year tine period, It is also refeLred to as the FUnctional-Basis earthquake, as it is a probable event within the tine pi:uµ:;;;ea: structures will be utilized ai the subject property. (Califoznia Divisiai of Mines and Geology lbLe Nlmtler 43, FebLuaJ:y, 1975);

Nmne of Fault ble. Maxinun Probable F.aLthqUake Richter magni'blde:

7.5 7.5 6.5 7.25

Eart:tquakes in the above Richter inagnitldes would be ccnsidered &f.Vfn:.

4. Maxinun (peak) Rock Aooelezatiai

'!!la maxinun (peak) roc:lt llQOt!l eration at the subject prcperty, caused by a Richter magni'blde 7 .5 maxinun pzt:taable eazthquake; l!01ld vary as a functkn of fault distance (GLeensfelder, 1974) as fol.lows:

Fault Distance

2 llliles 5 miles 10 miles 20 mlles 50 miles 70 miles

Maiinun (peak) Rock A<xel eratiai

.73g

.57g

.43g

.27g

.lOg

.079

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Burkhart

GORDON A. CI.OPINE callt!HL~O a:llOI•~ GSOWGlllT

RBD1.A.Nl)9, OA.I.JJ'ORNJ..6. 92.llt'a

November 25, 1985 Page 10 of 36

5. Repeatable High Ground Accelerations

J\ccording to Page and others, as described by Ploessel and Slosson (1974), a~ (peak) rock a=eleratiai !My caitrib.tte less to the cunulative danage potential than several cycles of less intense shaklii9." Therefore, repeated high ground acceleratiai should be of vital ooncem to structural design of any proposed structures on the subject property.

Available data imicate the relationship bet:I ieen maxinun (peak) rock acceleJ:atim and repeatable high groom acx:eleratiais at the subject property as follows:

Maxinun (peak) ltlck Acceleration

.73g .57g .43g .27g .10g .07g

Repeatable High Groun:l Acceleratim

.47g

.37g

.28g

.18g

.07g

.OSg

6. Duratiai of Ground Shaking

The duration of grnm:\ shaking has never been rigorously defined, and is estimated in a subjective manner only (Gl:'eensfelder, 1974) • Relationship bebieen Richter IMgnituie eartl'quak.es and the duratiai of strong i:tiase shaking can be estillated, however (Housner, 1970, p. 79, table 4. 3) , as:

Richter IMgnitme in vicinity of fault and subject ptopet Ly

5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5

Duratiai of strong Phase Shaking at subject property

2 sec::aids 6 seconds

12 seconds 18 seconds 24 seconds 30 seconds 34 seconds 37 seconds

7. Feriod of Bedrock Acceleration

Design criteria for buildings on the subject property should caisider the predaninant period of bedrock acx:eleratioo (Greensfelder, 1974) acccrding to the following table:

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l\ocel eratim Zena (g)

O.Sg 0.4 to 0.5 o.3 to o.4 0.2 to o.3 0.1 to 0.2 0.05 to 0.1

GORDON A. CI.OPINE co••tn.TDro U~•'P1*11%1 GJl.OLOOISW

RWUNDlll+ O.&LI'.PORNl.A. 11&'11

Novelllber 25, 1985 Page 11 of 36

Average Fault Distance Predaninant Perioo (in miles) (in secoods)

6 0.35 11 0.35 17 0.35 28 0.35 47 0.40 66 0.50

III. RE$JLTS CF STUDY - SITE GOOUX;Y

As briefly described above, the property under discussion in this :r:eport is located in a COil>~ area geologically, at the bollOOary bet ieen the Transverse Range yeato:r:phic province and the Peninsular Range gecm:>:r:phi!: province. Sit.e geology is daninated by this st:r:uctural. positim, with tectonic uplift of the San Bema:r:dino f.t>untains of the Transverse Ranges along the San Ardreas fault systen and :r:elated faults resulting in significant relief and active geologic processes during the tllole of the Pleistocene and Pecent ~ of the Q.Jaternary Period •

1. Ftx:k Types

~Sandstone and~l.ate:r:'at.e. In the Yucaipa Ridge area of the San ll£iJritilriS ( on l'i'iP 1, this repx t) , to the oorth of the

subject p:r:operty, the Mill Creek Fo:r:maticn of Gibson (1971) overlies ignscm and metal!DJ:phic rock types Of pre-eerx>~ic age. 'Die Mill Creek fo:r:m!lticn was the principal soorce rock for the clasts found in the ()la.ternary Older Alluvii.n of the subject property and the Yucaipa piemtai.t alluvial plain. Lithology of the Mill creek fo:r:natim coosists of highly indurated light b:r:cMrl a:r:kose and ccxiglanerat.e, with interbOOded dark qray to red-gray shale. Clasts of the conglanerat.e a:r:e sub:r:ounded to aubangular pebbles and cnli:i1 es of qranitic and ~c debris, with minor volcanics and sed:inenta:r:y rock types. Boulders of this rock to 3 foot diameter o::cur in the sedill'lents on the subject ptopet.ty.

()la~ Older A!luvii.n. 'lhls rock type is found over the wtvle of the Slibecl:p:r:Operty. It cxnsists of silt, 8111'ld, gravel, cobbles and boulders, principally of the Tertiary Mill Creek fal'll'etion described above. The alluvii.n was deposited by :r:epeated nudflow and fluvial activity f:r:an the ildjaoent San Be:r:rW:dino JIOllntains f:r:an hi9h voluie precipitatic:n that was often present as the San Be:r:na:r:dino m:lWltains \lieJ:e fo:r:ming and being uplifted to their present position during the Pleistocene Epoch of the Quaterna:r:y Period () millicn to 11,000 years ago.)

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GORDON A. CI.OPINE CQll'jlUL'rnrO imaJ•rElim» GllOLOOISZ'

REDU.NDI. O.U.IJ'ORNU e1a'1I

November 25, 1985 Paqe 12 of 36

The Pleistooene age for the Quaternary Older Alluviun has been established a:i the basis of lithologic character, incl\lling density, -athering, soil devel.optent, color, internal structure, and geologic setting. (Dihlee, 1982a, l982bi Matti, 1983).

!blocene Al.luviun. Recent alluviun (less than 11,000 years old) is currently Iri t.ransport frm the l!IJUJltain front source areas to the valleys below. unconsolidated light colored san::ls, gravels, and boulders are typical. '1'1e subject property is located near the head of the alluvial. plain of the subject property Md vicinity, as described earlier, and slopes southwest as the high terrace portion of the drainage to Live Oak Canym and San T:inoteo Creek. Dmediately north of the subject property (1000 feet) however, the drainage is to the west to Mill Creek and the Santa Ana River. Spoor Canym of the San Bernardino nountains northeast of the subject property drains to Mill creek, in part due to the right lateral offset of the Yucaipa piednalt alluvial plain south of the south branch of the San Ardreas fault :i:one.

lblooene alluvium is not found on the subject property, but it is in the nearby active watercourses of Spoor eanym, Wilson Creek, and their tributaries.

2. Local Structural Setting

As described alDve, the property un'ler discussia:i is located in a catplex :ilCllle of faulting involving the south Branch of the San A1¥lreas fault, the oak Glen fault, the Chicken Hill fault, and related splay faults. The oak Glen fault has been ma:pped variously: (1) en the State Alquist-Priolo map directly to the southeast portia:i of the property - but not extending across the property - with a ? at the property line, and (2) approxilnately 1000 feet south of the property, by Fife (1976) and ~land (1970). The oak Glen fault was not identified on the subject property during this investigation, it apparently dies out as the eastern property line is a~. Evidence for this interpretation is (1) It \>as not present in backhoe excavations oo. the subject property as a pa.rt of this investigaticn, and (2) right lateral offset alcng this fault Lecates progressively less across the active drainage channels in the s:mthMstem quarter of Secticn 19 frm east to west towm:d the subject property, This reduction of drainage offset is clearly seen on the aerial~. The northeast-southwest drainage at the southeastern pzq:ierty corner is not offset, but au drainages east of that locaticn across the Oak Glen fault are offset.

Smith and Seff (1984) describe a possible fault with a strike of North 400 East suspected in the drainage adjacent to the 8outheast corner of the property, east of the subject property but adjacent. Smith recumeids a 50 foot setlack fran this drainage in his repcrt; of 1984, and this reo::rmlmdation will be maintainai in this report •

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Burkhart

GORDON A.. CU)PINE cio.-•uz.TDrO .. QI•~ OIJCIJ.QOIS'

REDUN:DS. 04Uf'OB:Hl..6. •aa.'ta

Novettier 25, 1985 Page 13 of 36

Additional fault zones were app=iznately located as a part of this investigation, 380 to 400 feet SS?Uth of the subject property. These faults have a strike of North 7'S' West to North 85° West. Not shown on any official map, they are suggested in the report of &Iii.th (1984) where the "he!:man Fault" is approximately located. All properties in the vicinity of the subject property are appi:opciate for detailed geologic evaluation, with hackl¥le excavation, to precisely locate active splay faulting such as that descriliErl above.

3. Geologic Trenching and Analysis

Splay faulting, such as that descriliErl above, is camu1 in M'f structural setting silld.lar to that of the subject property. Natural exposures of Quaternary Older Alluvium do not exist on the subject property, and are very lilllited in the subject vicinity. Prior geologic t.'Ork in the vicinity by &Iii.th (1984a, 1984b)i Clopine (1983) (1984) (1985) I Rasmussen (1982)1 serve as exartpl.es to dewnstrate the need to conduct detailed backhoe excavatians and analysis to docurtent site geology.

As a part of this investigation, 503 feet of backh:>e trench was excavated, across the whole of Parcels 2,3, and 4, as shown on Map f3, a part of this report. The o::ntinuous trench was excavated to a depth of 11 to 12.5 feet, the nwdrrun practical acoording to currently accepted practices for geological investigatiais. Trench excavaticns ~e very thoroughly cleaned, evaluated, am logged according to standard geologic practice. (Taylor and Cluff, 1973) •

All nx::k seen in the trench eiicavatialS was Quaternary Older Alluviin, as shewn in detail on the trench lCXJS (4 sheets), a part of this report. Deposits were typical Quatemacy Older Alluvium, as described in this Ieµn:t, item III, 1. The upper portion ws m:derately dense, dry, phenoclastic, with clasts predaninently of Mill Creek fannation of Gibetti (1971), o::nsisting of light brown sanistone and oongl.anerate, with qrey shale, wl.l indurated, 1"'hlch W!IS deposited fl"Clll a source area of the Yucaipa Ridge region of the San Bernaidino 1tuntains during the Pleistocene. Clasts were subrouTJ:led to subllngular. Bedcl i ng was absent to p::xn:. Crude stratification was identified bet ie en variais boulder, cobble, qravel, and saoo units as sl'xlwn en the trench logs. LcMer portions were similar in lithology Wt denser.

It is my opinion that the Quaternary Older Alluviin, ~ch is the cnly nx::k type present an the subject property, was transp:>rted to the site predaninently by nuiflow, during climatic conditions quite different fl"Clll those at present. A nwt>er of nuiflows are postulated, as ftie!iOClastic deposits of this character would require greatly increased availability of surface waters, such as would be available ally during the Pleistocene pluvial tine intervals. Following dep:>sition, sheetwash of nmflCM deposits would partially rem:we finer sediment, and caicent.rate the larger clasts, as seen in trench dep::Jsits. 'Itlis sequence

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Burkhart

OOJ<DON A. CJ'.A)P!NE eQ:.q;og-~~o -..i:n•~ o•ot.0ctn

REl>J..AN.DS, O&LIIPORNU. Ull.'18

NoVeiber 25, 1985 Page 14 of 36

of events has been noted and un:ler stufy by the author in historic nudflows in Death Valley (at the Salt Pools turnoff north of 13adwater), at 'Wrighbiiood (Heath creek lllldflowl, and el!IE!\olhere. Holocene and historic stability of the existing land surface has resulted in the developnent of a fairly well developed soil bxil"!On.

No cracka, joints, liquifactioo effects, or faulting was present in any trench excavation.

Drainage: a m1oor local drainage exists on the subject prq:ie;rty, as shown on Map #3 of this reprt.. 'Ihis drainage is not significant to site geology, unless upstream nalifications by local property owners or future developnent causes drainage that otherwise would utilize Spoor creek drainage to Mill creek or the un-ruured drainage east of the subject ~ to flood onto the subject property. 'rtlis will be discussed in this repozt un:ler Conclusions and Raxxtftenlations. As stated previolsl. y, the property is located near the heazwaters of the Yucaipa Valley d;rainage system fran the nnmt:ain areas narth of the subject property to LiVl"l oak c.anyoo or· the Mill ~-&mta Ana drainage.

Topsoil of the subject property was darrp t.o a depth of 1-2 feet, due t.o rain and snow ~ that tO'lk plaO(! on N:.waltler 11 and 12, 1985. No free groum­'2ter \>Us present in trench exc:avations. The prq:ierty is located in the Triple Falls Creek groundwater sub-basin of lt>reland (1970) , and the groundwater table is estimated, base:'.! on data of i'breland (1970) and CarSQl (1982), at ai:proxirnately 300 feet below the existing land surface.

IV. OJN:ll!SIWS J\ND ~TIOOS

1. 'lbe subject property is located in a Special Stlrlies Zcne, as defined by the State Ge:>logist, and provisions of the A!quist-Priolo Special studies Zale Act apply. In my opinion, greater seismic/geologic: risk exists on properties located in Special Studies zones, ~ t.o areas not included in such l"!OneS.

2. The building site areas of each parcel, namely !IDSt all areas of Parcels 2, 3, Md 4, have surficial sedinentary rock designated at Quaternary Older A!luviun. ~ foumation and structuJ:al engineering is done for arry proposed ilrprovemnt at any subject site, attention of engineers is directly and apecifically directal at the geologic and seismic informatioo contained in this report for mitigation of.the seimnic events caisidered likely and~ during the lifetin! of use of JU'OIX>sed ilrprovements. standilid aralitectur and structural design is not awi;opz:iate - architectural and structural design must be apecifically adopted for this subject property.

3. Earthquake insurance is recameided for proposed improveoonts en the subject parcel.

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Burkhart

GOllDON .A.. CLOPINll: ci(l.-.l;JL't"Dttl :lll::llo.1111~ tDOLOODT

rutD:tJ..Nn•. C.&I.lFORNU ltst•'fa

NolTelrtler 25, 1985 Page 15 of 36

4. No zone of faulting is present on that JX>rtions of Parcel 2, 3, and 4 not shown in yella.i on Map #3, a part of this report. ACcording to currently accepted practices conceming the acceptable levels of allONable risk, it is judged that those areas of Parcels 2,3, and 4 not shown in yella.i on Map #3, of this report, are free of active faults and are acceptable building sites fran a geologic/seismic consideration.

5. A 50 foot setback fran the aoutheast property corner has been .recamended by Registerai Geologist No. 2966 due to a suspected fault following the drainage in that area trend!ng 1'brth 4rf' EaSt to Spoor canyon (Snith, l984bl. (His rep:>rt states N:>rth 23° East, but his map shoWs North 4rf' East). It is appropriate to re-affinn this Ieo:xmeidation, and this setback is shown on Map #3, a part of this report.

6. No existing landslide exists on the subject parcel, and the hazard fJ'.all landslide is ju:igerl to be la.I to absent,

7. '!he liquifaction potential for the subject property is judged to be la.I to absent, ccnsidering the depth to ground water' (over 50 feet) and the nature of the surficial sediltentary Older Alluviun.

8. Potential for hazard due to tsunami, seiche, lava fla.i, or other volcanic hazard is judged to be absent.

9. A potential for grourxl =acking/lurching, and severe seimnic shaking exists en the subject prope:i: ty, due to the close proximity of the San Andreas and related faults, as described in this reJX>rt. 'Itiis potential, however, is no greater on the subject property than any other similar area across the YUcaipa or San Bernardino valley adjacent to any major fault zaie. Adequate structural and fCAl!ldaticn engineering is essential for proposed ~ts, as no geologic mitigaticn is possible for these potentials, other than stating the geologic/seisnic consideraticns and analysis ccntained in this Iepxt.

10. There is no potential for ~e induced flooding of the subject property, given current upstream inqJiovernents. Ptopetty owners are cauticned, however, to be oertain that existing surface drainage channels across the existing land surface in the subject property area are not datme'l, filled, or otheiwise obstructed by upsti:eam landowners, as this CCl1ld cause serious caiplications to the subject property if a severe precipitation pericd sl¥>uld OCCU1".

ll. No fill or artificial sediment is preBe11t on the subject ~. and the nature of the alluvial Jllt\terial present is such that adequate fCAl!ldation reca1wendations should be prepared by the fCAl!ldation engineers for the proposed ~ts. It is recamended that JeXJmeildations for f0lll'K2t.ioru; be obtained by a soils Engineering f.llm prior to constructicn of :inproverents •

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Burkhart

GORJ>ON If.. CLOPmE ~QJl"•VJ'.~IOI U<n•~ OaoLOGqT

REDL.6.NDS. O.&Lll"OHNtA. 911112'8

Nall6nber 25, 1985 Page 16 of 36

12. Factors incllKled in this repxt umer Seismic COnsiderations and Analysis are incllKled as COnclu.sicris and Reoameldaticris.

13. COnsiderations such as erosial of graded areas, alteraticri of rumff, unprotected drainageways, increased inparviou.s surfaces, land subsidence -should not be any problem, if no1'TM.l. and reasonable engineering practice is follcwed during developrent.

14. This investigaticri involve:l field stmy, site and trench analysis, regional and vicinity geologic evaluation, backOOe excavatiai, geologic evaluation of maps, reports, personal notes, and maps, in oonfo:cmance with both State arrl COunty guidelines and requi.renents for geologic reports, It has, therefore, been conducted aoconling to l'lOtTl\'ll and reasonable geologic practice. o.ir professialal l!lel.Vi.ces have been performed, our findings obtained, and our reu::amerldations prepared in accordance with accepted geologic principles and practices. This -rranty is in lieu of all other -=anties either e>Cpressed or inplied.

15. Guidelines and policY of the Land Managarent Ilepartllent, COunty of san Bernardino, IOere follcwed specifically during the sbrly and prepai:atiori of this report cri the subject property.

16. The trench excavation was backfilled and wheel-rolled, but not OCTipaCted to original ground. The location of the trench is precisely shown on Map #3 of this report, for the very i.np;lrtant pirpose of being able to locate it lipeCifically in the future,. Any human occutWICY structure placed within 15 feet of the excavated trench shalld receive specific evaluation by the foundation/soils engineer prior to selection of placerent of proposed structures. The trench is precisely shown on the Site Developrent Map, a part of this report, for this p.irpose.

17. The potential for land subsidence is very low, due to the nature of the setiJTetltary ro:::k exposed on the property. Any fill placed on the subject property in any manner llllSt be placed in acoordanoe with the Uniform Building Code, Appendix Chapter 70.

18. Should conditions be enoountered during any future dellelcpnent that appear to be different frcrn those described in this rep::>rt, I lil'lould be notified :Umediate that awropriate zecamerdations be prepared.

,s"" tq,, '<;'<,,"' 'Cr,,_ Respectfully sul:lnitted,

GORDON A. * CLOP\ NE

No. 511 * -~OV\a·

Gordcri A. Cl.opine Registered Geologist No. 511 State of California

certified Professialal Geological Scientist No. 6125 Anerican Institute of Professional Geologists

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v. REFEREN::ES

GORDON A. CLOPINJI: (l(llf.UL'rDl'O .. (llUIT!m:mD OZOLICKJm2'

RB.DL.&.Nl>ll, O..U.tl"ORNI..&. 8Jl!:ITI

Noveliler 25, 1985 Page 17 of 36

Alfors, J., Burnett, J., and Gay, T., Jr. 1973: "Urban Geology Master Plan for california", California Division of Mines and Geology, Ilulletin 198,

Allen, c., 1957: "San lln'lreas Fault in Soothern California" Geological Society of J\rrerica Bulletin, Vol. 68, no. 3, p. 315-350.

Allen, C., Saint.AllaBl, P., Richter, c,, and Norquist, J., 1965: "Relationship Bebieen Seisrnicity and Geologic Structure in Southern califomia Region", Sesim:>logical Society of JVrerica Bulletin, Vol, 55, no. 4, p. 753-797.

Bonilla, M., 1970: "surface Faulting and Related Effects" Chapter 3 of F.arth:iuake Engineering, Prentice Hall Publishers, Englewood Cliffs, N.J., p. 47-74.

California Division of Mines and Geology, July 1979 and April 1985: ·~ Epicenter Map Update I and II, California Geology, abo'Je elates.

California Division of Mines and Geology: Note NurtDer 37: "Guidelines to Geologic/Sei9llic Reports", 8/73 Note N\mber 43: ":R.ec:umerrled Guidelines for Detennin1ng the Maxinun 'Credible

and the Maxinun Probable Earthquakes", 2/75 Note Nunber 44: "Reo:mnended Guidelines for Preparing Engineering Geologic .Reports",

4/75 NOte Nmtier 46: "Guidelines for Geologic/Seismic COnsiderations in Enviral!rental

In;iact Reports", 6/75 Note tbltler 48: "Checklists for the Review of Geologic/Seismic Reports" , 9/75 Note NurtDer 49:"Guidelines for Evaluating the Hazard of SUrface Fault Rupture"l0/75

Carson, s., and Matti, J., 1982: "contour Map showing Mininun Depth to Ground water, UWer Santa Ana River Valley, California, 1973-1979", united States Geological survey Open-File Report No. 82-1128.

Clopine, G., 1983: "Geologic Investigation of a Portion of a 9.29-Acre Parcel r«>rth of carter Street, F.ast of Jefferson Street, Yucaipa, San Bernardino County, California" 26 pages.

Clopine, G., 1984: "Geologic/Sei9llic Investigatkn of a Portkn of Parcel 4, Parcel Map No. 5509, A Portion of the Northwest Quarter of the Southeast Quarter, Section 20, Township 1 ScA!th, Range l West, S.B.B.&. M, Yucaipa, San Bernardino County, California", 26 pages.

Clopine, G., 1985: "Geologic/Seisnic Investigation of a Portion of a 8,97 Acra Parcel at the Northeast Corner of carter Street and Norton Avenue, A Portion of the ~st ()larter of the Southeast Quarter, Section 20, Township 1 South, Range 1 West, S.B.B.& M., Yucaipa, San llernardino County, California" 27 pages.

• GORDON A. CLOl'JNll:

coirau:i.rnro m11101•TS11.SP fiilll!~Oll'S'

REDUND.11, O.&Ll:POHNI.&. 928T8

NoveTtler 25, 1985 Page 18 of 36

Clopine, G,, various dates: personal notes and geologic reports and maps en properties and investigations related to the subject of this report. (1961-1985)

Cra.oell, J.: "San Andreas Fault in Southern California", california Division of Mines and Geology Special Report No. 118, 1975.

Diblee, T. , Jr, , 1964: "Geologic Map of the San Gorgonia llbuntain Quadrangle, San Bernardino and Riverside Counties, california", united states Geological Survey Miscellaneous Geologic Investigatiais, Map 1-431.

Diblee, T., Jr., 1968: "Geologic Map of the Yucaipa Quadrangle, California" United Stat.es Geological 5urvey Open File Map, August, 1968.

Diblee, T., Jr., 1975: "I.ate Q.Jat.emary Uplift of the San Bernardino Mountains en the San Andreas and Related Faults" in Crowell, J. , cited above.

Diblee, T. , Jr. 1982a: "Geology of the Transverse Ranges, Southern california" in Geology and Minel'al Wealth of the California Transverse Ranges, Fife and Ribch, cited below.

• Diblee, T., Jr., l982b: "Geology of the San llernardino ltalntains, Southern California" in Geology and Mineral Wealth of the california Transverse Ranges, Fife and Minc::ll;" cit.ed below.

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Dickenson, w., and Grantz, A., 1968: "Proceedings on Ccnference on Geologic Problems of the San Andreas Fault System", Stanford University Publications, Geological Scienoes, vol. XI., Stanford University, Stanford, california.

Dutcher, L., and Burnham, W., 1959: "Geology and Ground Water Hydrology of the Mill Creek Area, California", United States Geological survey Open File Report, p. 1-229.

Dutcher, L., and Garnett, A., 1963: "Geologic and Hydrologic Features of the San Bernardino Area, california", United States Geological5urvey Water SUpply Paper fl419.

Dutcher, L., and Burnam, w., 1960: "Geology and Ground Water Hydrology of the Redlands-Beaimmt Areas, california", United States Geological 5urvey Open File Report, p. 1-352.

Fife, D., and others, 1976: "Geologic Hazards in Southwestern San Bernardino County, California" california Di visial of Mines and c.eology Special Repo:r: t 1113 •

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GOJtDON .&.. CLOPINE tlOlltllli'Q":r,.'!"Dl"g. KJ!GlllrKmlllD 0•01tlCHJm2'

RBDL.&.lmll, O.&Lll"ORNU.. U2B.T8

Noverrd::er 25, 1985 Page 19 of 36

Fife, D., and Minch, J., 1982: "Geology and Mineral Wealth of the California Transverse Ranges", South Coast Geological Society, p. 1-698.

Geologic Map of California, San Bernardino Sheet, california Division of Mines and Geology, 1969.

Gibson, R •• 1971: "Non-Marine Tu:rbidites and the San Andreas Fault, San Bernard:iJD M:ru,ntains, California" in Elders, w. "Geological Excursions in Southern California" University of California-Riverside Cm!plS Muaeun publication, field trip No. 9, p. 167-181.

Greensfelder, R., 1972: "crustal ~t Investigations in California- Their History, Data, and Significance", California Division of Mines and Geology Special Publication #37.

Greensfelder, R., 1974: "Maxirrun credible ~ Acceleration fran Earthquakes in California", California Division of Mines and Geology Map Shoot #23.

Hart, E., 1980: "Fault Hazard Zones in California" California Division of Mines and Geology Special Publication #42.

lbpe, R., 1969: "Maps showing Recently 1\ctive llreaks Along the San Andreas and Related Faults beb1ee11 Cajon Pass and the Salton Sea", tlnited States Geological Survey Open File Report.

lbusner, G. , 1970: H Strong Ground M::>tion n , in Weigle. R. • 1970, "F.arthquake Engineering", Prentice Hall Publishing Catpany, Englewood Cliffs, N.J., p. 75-92.

Jennings, C., 1973: "State of California Fault and Geologic Map", California Division of Mines and Geology Preliminary Report #13.

Jennings, c,, 1975: "Fault Map of California with Ia::ations of Volcanoes, 'l'hermal Springs, and TheDnal ~lls", California Division of Mines and Geology, Scale: 1:750,000

Kovach, R., and Nur, A., 1973: "Proceedings of the <:niference on Tectonic Problems of the San Andreas Fault system•, Stanford university Press, Vol. XIII, Palo Alto, California.

Lamar, D., Merifield, P., and Proctor, R., 1973: "F.arthquake Recurrence Intervals on Major Faults in Southern California", in Mxan and others, 1973, cited below.

Lung, R. , and Proctor, 1966: "Engineering Geology in Southern California" Association of &lgineering Geologists Special Publication, p. 1-389.

Matti, J. , and others, 1983: "Mineral Resources FOtential Map, Ray.aid Flat lhadless Areas, California", United States Geological Survey Miscellaneous Field St•xlies Map MF- 1563A.

•

•

GORDON A.. Cl.OPINE (1.0:111'.~LTDfO IBDillTKRlll!I (;l•OLOOUT

REDl..&.NlJli, CALlJ'ORNli. 02a,.a

N::JVerttber 25, 1985 Page 20 of 36

M:>ran, o., and others, 1973: "Geology, Seismicity, and EnviLaatental Iltp:lCt:" Asaociatial of Engineering Geologists Special Publication, p. 1-445.

~. J., 1970: "Artificial Necharge Yu::aipa,California", United States Geological survey Open File Report, p. 1-44.

Ploessel, M., and Slosson, J., 1974: "Repeatable High Ground Accelerations f:ran F.arthquakes", califoi:nia Geology, vol. 27. no. 9, p. 195-199.

Rasrmissen: see below Real, c., Toppozada, T., and Park, o., 19781 "Earthpake Epicent.er Map of Califonll.a", califonU.a Division of Mines and Geology Map Sheet 1139.

san Bemardino County, 1974: "seisnic and Public safety Elerrent", san l3ernaLdino County General Plan.

San .BemaLdino County, 1984: "Alquist-Priolo Geologic Fault Hazard Stu:ly Requi.rem:!nt" P• 1-3.

Schnable, P., and Seed, H., 1973: "Accelerations in Rock fOL F.arthquakes of the Western United States", Bulletin of the SeiSTDlogical Society of Jlmerica, vol. 63, no. 2, p. 501-516 •

Snith, c., 1984a: "Geologic Hazards RepOit: Gary Jeffers Parcel, 10142 Hope Lane, Yucaipa, California"

Snith, C., 1984b: "Geologic lta2aLrls RepOrt, Five ACre Parcel, IDt 1, Block O, YUcaipa Valley colony SUbdivision No. 2, Ylx:aipa, California"

TaylOL, C., and Cluff, L., 1973: "Fault Activity and Its Significance Assessed by Exploratory EKcaVation", in J<ovach and Nur, 1973, cited above.

wallace, R., 1970,: •Eartlx]uake Recurrence InterVals on the San AndLeas Fault" Geological survey of Jlmerica Bulletin, vol. Bl, p. 2875-2889.

Rasrrussen, G., 1982: "Engineering Geology Investigation Portionof Parcel 3, Parcel Map No. 5509, Af.P=xinately 646 Feet F.ast of Norton Avenue, Portion of NWl/4 Of SE 1/4 Of Section 20, TlS, RlW, SBB&M Yooaipa, California" •

• • • Burkhart NoYer!tier 25, 1985 !!2! 21 of 36

REIATED - 'ro cmuxrrc FNJI:r ZAZAID S'ruDY R!!Q1IRllM!!Nl'. Sl\N BEIU\H)DI) CllJNI"l, THIS IS A •sl'l'E MAP·

Page 1, "Procedures•• CEN'mR CF SJL'TIOO 19, ~IP 1 OORTH, ~ l WEST, S,B,B.&M. EXIsrnt;

Itan 1 , SURl1E'l M'.HlMENI' R.C.E. 8591 ~

~of~ ·~ TtaiCh is sl:™1~ -1.-- IVY AVENUE -,.

The tx'i!ilch exi.• es cmtinuoosly • -eiqxi •d geologic units and features 330 feet0

273 feet, N. sff' W fran . rmth end of trench

to existing survey ifUIU<l!!l1t v-"-.. DIS'l'JllCE 'ro E>CISl'nt; 9JRVEY MHHNJl IWICA'l1!D KUR>IK> TO R!QJIRl'JolfNl' CF GFrJ[OOIC FAULT Hl\ZAIC ~ S'lUDY ~ C'l'Dl·"'*I' a:xJNl'Y CF Sl\N BERNMDml •

RrK UNIT:

~--~~~~~~:--:"'::::lOOfeet~~~~~~-===:::i== Paroel l: 'Ihi11 area mt included mider ,

C'oonty Geoloqie Fault Hazard Study PA10!:L cm:~t, page 2, itan 2, ~

2. iten a)

<>oai

EKist:ing P'eme O:itil&C

~ f Wire~ I ~ 62"

. ._ITLE

().laternai:y Older Alluvitin (Pleistocene)

Lithology diSCW!Sed in text of Report

Precise l.Oca~ 6f 'Jll!IO].ogic tl:enches indicated with the distances to existing survey llDQlm!nts shown.

• Existing PeWer Tn!e

Pr• p oaec1 8'1i ldinq Pads irdidlted. C'oonty Definit:icn: A buil.dinq area with a minhun of 50 foot safety factor as de!Dnstrated by direct ~ti.at of cmtinucusly exp-se1 geologic units and feittures"

N:l AREA 00 'ft!IS MAP IN A BJIDOO s:.::L..--U­AREA IS AN ARFA CF oooraxc HAZAND l'Ll.µILl.L~ TO 'nlE GEl)U:X;IC FNJLT lD\ZA!lO S'1'UDY RWO!REMmr, CllJNI"l CF San Bernardind

N

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of <fJaije'lNE No. 511

OCJ\LE: 1:600

linch=50~

*

N:l AREA 00 'ft!IS MAP Rl!J)JIR!S FURTHER Gl!XUlGIC STUDY JO::IRlIK> TO

'nlE a::mm GFJTtx:TC FNJLT HAZMD S'l\1DY RfX1JIRIMN1' (on a building site -· pMQels 2,3 and 4)

srm tEYEla'Ml!NI' l'W' GB'(ffllC ~ TRE2DI IIXld'1tfi MM'

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- ------ -----

CLOPINE GEOLOGICAL SERVICES R.G. #!!Ill

REDLANDS, CALIFORNIA 92373 I.e. (714) 794-6700 IN'-

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sinql.C!! family~ frmie "l1lllmt ~ structures• of two stories oi: less.

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; QoaJ.

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•

Page 23 of 36

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Page 24 of 36

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Page 25 of 36 GOROON A

CLOPINE No. 511

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CLOPINE GEOLOGICAL SERVICES R.G. #511

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•

•

GORDON A. CWPINE (:1;1111r111I,t.1..TIXO BEOlSTBJIBQ (111:0LOOI•r

:REDLANDS, CALlJ'ORNI ... g2378

NoveltJer 25, 1985 Page 26 of 36

Prominent ean:hi:iuakes in California 1 1769 through September 1971 1 (Intensity VII I and above)

Date

28 Jul 1769 8 Dec 1812

21 10

1Oor11 9

26

Dec Jun Jun Jul Jan Nov Nov

3 Jul 1 Oct

Oct 8

1836 1838 1855 1857 1858 1860 1861 1865

21 Oct 1868 26 Mar 1872 19 Apr 1892 21 Apr

4 Apr 1893 20 Jun 1897 14 Apr 1898 22 Jul 1899 25 Dec

27&31 Jul 1902 18 Apr 1906 28 Apr 28 Oct 1909 11 Jan 1915 22 Jun 21 Apr 1918 21 Jun 1920 10 Mar 1922 29 Jun 1925 22 Oct 1926 20 Aug 1927

4 Nov 25 Feb 1930

1 Mor 6 Jun 1932

10 Mar 1933 7 Jun 1934

18 May 1940 30 Jun 1941 15 Mar 1946 29 Ju I 1950 21 Jul 1952 22 Aug 25 Apr 1954 21 Dec 12 Sep 1966 8 Apr 1968 1 Oct 1969 9 Feb 1971

RE!9ion

Orange County 1 near Irvine Southern California. Off coast of southern California Hayward fault, Berkeley. S~n Francisco re9ion 1 San Andreas fault. Los Angeles County Fort Tcjon-Carrl20 Plain San Jose Humboldt Bay Near Livermore Fort Humboldt-Eureka area. Santa Cruz Mountains Hayward. Near Lone Pine Vacaville. Wi nter5. Northwest of Los Angeles Near Hollister Mendocino area San Bernardino County. San Jacinto-Hemet area , Santa Barbara Co~nty San Fr~ncisco re~lon .. Brawley, Imperial Valley Humboldt County. Los Alamos El Centro-Calexico-Mexicali area San Jaclnto-Hemet area Inglewood. Cholame Valley Santa Barbara area Monterey Bay Humboldt Bay West of Point Arguello Westmorland. Brawley. Humbo 1 d t County . Near Long Beach. Parkfleld. Imperial Valley. Santa Barbara-Carpinteria area North of Walker Pass Imperial Valley. Arvin-Tehachapi. Bakersfield. East of Watsonville. Eureka Truckee. • • Northeast San Diego County Santa Rosa San Fernando

Richter Magnitude

Possibly 8

Possibly 8+

8.3 6-6.9 6+.

6.25. 6.8

6.5 6.3 6-6.9

7.5 s.o 4.5 6.4 6.3 6.0 7.1 5.9 6.25. 5.5 7,7 5.8 5.25. 6.6 6.6 6.5 5.7 6.5

Modified Mercalli

lnten$ity

• VI 11-1 X .x • I X-X .x . VI 11 .X-XI • VI 11 . VI 11 • VI 11 • VI 11-1 X . VI 11-1 X . I X-X .X-XI • IX • IX . VI I 1-1 X • VI 11 . VI 11-1 X • VI 11 • IX . VI 11 . XI . VI 11 . VI 11 • VI 11 • VI 11 • IX .VI 11 • IX • VI 11-1 X . VI 11 • V 11 I . I X-X • VI 11 • VI 11 • VI 11 . IX . VI 11 • x .VI 11 • VI 11 • VI 11 .XI • VI 11 . VI 11 • VI I . VI 11 • VI I . VI I -VI 11 . VI I 1-X I

~C·URC::;: Ct.1if<)rn1 a G1~ol og;r, r;uv .. ~:;ib~r 1?71 1 ~-· ~"tl -~ . .i:-h.:~11 :.::t· C·~1 ·· !:1 :i:_.~~ .. ~~

Di ·.t?.~:i.ci1 of r-:ba.c; r:in<l Gcvlot:r •

•

•

GOHDO.'l' A. CLOPINE CO:S-6ULTINO lll:l~l!iTERBD GEOLOOIB'r

HEDLANDS, OALIF'ORN'lA.. 92373

Burkhart November 25, 1985

MODIFIED MERCALLI INTENSITY SCALE OF 1931

The first scale to reflect earthquake intensities was de~ •eloped by de Rossi of Italy, and Fore! of Switzerland. in the 1880s. This scale, with values from I to X was used for about two decades. A need for a more refined scale in­creased with the advancement of the science of seismology, and in 1902, the Italian seismologist, Mercalli, devised a new scale on a I to XII range. The Me.rcalli Scale was modi· fied in 1931 by American seismologists Harry 0. Wood and Frank NeumRnn to take into account modern structural features:

II

Ill

IV

v

VI

Vil

Not felt except by a very few under especially favor­able circumstances.

Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended ob· jects may swing.

Felt quite noticeably indoors, especially on upper floors of buildings, hut many people do not recog· nize it as an ea..i thquake. Standing motor cars may rock slightly. Vibration like passing of truck. Duration estimated.

-< During the day felt indoors by many, outdoors by few. At night some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Stand­ing motor cars •ocked noticeably.

Fell by nearly everyone::, many awakened. Some dislies, windows, etc., broken; a few instances of cracked plaster: un!>table objects overturned. Distur­bances of trees, poles, and other tall objects some­times noticed, Pendulum clocks may stop.

Felt by all, many frightened and run outdoors.· Some heary furniture moved; a few instances of fallen plaster or damaged chimneys. Damage slight.

Everybody runs. outdoorS. Damage negligible in buildings of good design and construction; slight to moderate jn well-built ordinary structures; consider­able in poorly bui't or badly designed structures; some chimneys broken. Noticed by persons driving motor carS. •

VIII Damage slight in specially designed structuresj conr siderable in ordinary substantial buildings, with par­tial collapse; great in poorly built structures. Panel walls thrown out of frame structures. Fall of chim­neys, factory stacks) columns, monuments, walls. Heary furniture overturned. Sand and mud ejected in small amounts. Changes in well water. Persons driving motor cars disturbed .

IX Damage considerable in specially designed struc­tures; well-designed frame structures thrown out of plumb; great in substantial buildings, with partial collapse. BuildingS shifted off foundatioits. Ground cracked conspicuously. Underground pjpes broken.

x

XI

XII

Page 27 of 36

some well~built wooden structures destroyed~ rnost masonry and frame structures destroyed with fown~ dations; ground badly cracked. Rails bent Land· slides considerable from river banks and steep slopes. Shifted sand and mud. Water splashed (slopped) O•cr banks.

Few) if any; (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Under~ ground pi.,Pelines completely out of service. bo.rt11 slumps and land slips in soft ground. Rails bent greatly.

Damage total. Practically all works of constn..1ctioo are damaged greatly or destroyed. \\''aves seen on ground surface. Lines of sight and level are di~­torted. Objects are thrown upward into the air.

COMPARISON OF MAGNITUDE AND INTENSITY

It is difficult to compare 1nagnitudc and in tens;,· because intensity is linked with the particular ground 3: structural conditions of a given area~ as WC'll as distJ.Til'i.' from the earthquake epicenter) while. magnitude is a nicJ· sure of the energy released at the focus of the earthquake.

Richter Magnitude

2

3

4

5

6

7

8+

Expected Modified ~tercalli Maximum Intensity (at epicente~)

1-11 Usually d<tccteJ only by instnln1ents.

lll Felt indoors

IV -V Felt by mo•t people; slight damage

VI-VII Felt by all: many frightened and run outaoors; damage minor to moderate

Vll·Vlll faerybody runs outdoors; damage moderate to ma1or

IX-X

X-Xll

Maj or damage

Total and major dama[!:cs

After Charles F. Richter, 1958) Elementary Seismology_

Fr"(EI California Divillim of Mines am. Geology Notes t23

• Burkhart Noventier 25, 1985 Page 28 of 36

FAULT-RUPTURE HAZARD ZONES

IN CALIFORNIA

by Earl W. Hart

INTRODUCTION

The Alquist~Priolo Special Studies ZonC'S Act was signed into 1a""'· Pecember 22 1 1972, and \\:ent into effect March 7, 1973. The Act, codified in the Public Re~outces Code as Division 2, Chap­lcr '1.5, ha~ been amended four times. A con1plete h~x.t l)f the Act

.is provided in Appendix A. The purp0sc ofthi~ Act is to prohihil the location of niost stn.1CTUtes. for hun1an occupancy across the traces of active r~uhs. and to mitig.atc lhereby the hazard of fault-rupture (Section 2b21.5).

Under the Act, 1he State Geologist (Chief of the Division of Mines and Geology) is required to delineate ·~special studies zones" along koown active faults in California. Cities and coun­lics affected by the zones must regulate certain devdopnlent "projects" within tht: zones. They mu:'it withhold development permits. ror sites within 1he zones. until geologic iovestigations

dcmonstnue that the siles are not threatened by surface di:r.rlace· ment from future fauhing. The State Mining and Geology Board pr1..)".,.·ides specific Polidl:$ and Criteria to guide cihes. and coun­he'.'i in their impkme11tation of the I.aw. A summary of the princi­pal res.ronsibilitics and functions required by the Alquist~Priolo Act t.i.ri: ghr'en in Table I. The Policies and Cri1eria a.re s.umma· rized in Table 2, and the cornple1e tc:xt is provided in Appendix. B.

This publication identifies and d~ribes (1) ac1ions taL:.en by the State Geolor,ist 10 delineate Special St1,1dief> Zones., (2) poli­cicto u~i::d to make Ztlning decisions, and (3) Officia.1 Mars of Spec:lal S1t1dic-s Zones. issued to date. A continuing program !O evaluate f!luhs for future ztining or zone revision abo is summa· tit.i:=d. Other asp<cb, or the Alquist-Priolo Spceial Studies Zone~ Act and it!i. implementation are dif.CUS'.'ied by Hart (1978).

lriformallon pre-scnled hi:=re is ba~d on various in-hou~ docu· men1!. and puhli\·utiOTi:!i. of this author and others or the Dii,.·ision. The princlral puhlit·::&tion!I are ci1ed iti the list of references. The

• assist.ani,;1;:: of Ju.mes G. ~1orC'no (compiloition of faults on Figure 5). Marilee: Baili:y a.rid R11.:hard R. Mo.ar (d.-afling), Joii Lloyd (editing), and tither tc:c:hrili.:al and clerical staff uf lhc Divi~ion in n'.'\ising 1hi~ repart is gratefully acknuwkJgc:d.

Tcbl~ 1. Summary of '~sponsjbi/lli~~ ot1d f4.1nclicns under lh~ Al­quisl-Prlolc Sp~cial Stvdi~s Zon~s Act /J.t!e Appf:ndi~ A /ct full text of Act).

-----~--- State Grologi.~·t ---------

1. Delineates Special Studies Zones; compiles and i~:o.ui::s. nlap1i­to cities, counties, a11d :-.t.a1e agencies (Sec. 2622). a. Preliminary Review M~p:o.. b. Ofiicial Maps.

2. Reviews nc:w data (Sec. 2622). a. Revises i:~i!Sting n)ap~. b. Compiles new map!i..

3. Approves reques.ts. for waivers initiated by citit:'!I. ::i.nd coun­ties (Sec. 262:l).

-----State Mining and Gc-o/ogy /loll.rd-----

1. Formulates. policies and criteria to guide ci1ies and C"11u1Hie ... (Sec. 2621.5 11nd 2b23).

2. Serves as Appeals \lo><d (Sec. 673).

--------Cirir:-.'i JJnd Counti~ --------

1. Must adopt zoning laws., ordinances. rult..'"i, and rcg\1\a\h)ll'-;

primar)' res.pon~ihih1y for 1olpli:::nh~nting. Al·t (S ... ·c. ~f)~l.5) 2. Rtgulates. specified ··projecl:-. .. wi1hin SpeLial Studi ... · ... Z1111e-.

(Sec. 262J). a. Detc::rmine-s need ror geologic report\ prior 10 proji..:i.:1

develorment. b. Arrroves geologic reporl~ prior 10 i:-.:o.uin£ dc:11clop1n1.:111 pc:rrni1s. c. May iniliatc waiver procedures.

3. May charge rt~!.Onable f~i:::o. for adnlini~lnHive co~I!. (Sc-L 2625).

----------Other----------

1. S~i'imic 5J.1f~ty Comn1i~"Sion - advi:-.e::-. Slate Gcolo~1 .. 1 and S1ate Mining and Geology Board (S<c. 26.10).

2. State A[:t"tlf.:ic.~· - ptohibiti:=d from 1t.iti11g ~1rui;1ure:-. aero ........ active falllt trar;i:!j (SeL. 2021.5).

.3. Disc:/o.~ure ~ prospi:Ll1vi:= bu) t:r'.'i of any rt"1tl prllperi ~ llx·:u­ed v.·ilhin a Special Studie:-. Zone niust hi: rw11ificd nfthat fai.:1 (Soc. 2b21.q),

•

•

November 25, 1985 Page 29 of 36 2 CALiFURNIA DlvlsmN or MINES AND GEOLOGY SP 42

Table 2. Summory of pc!i,le$ end criteria cdapled by lhe Staftt Mining ond O~logy 8aard (Jee Appendix B for full /~xi) .

----------Policies----------

I. Suggests. methods for the review of Preliminary Map~ ptior to issuance of Official Maps.

2. Dcfin~ ac1i ... e fault (equals potential haz.ard) as a fault that has had surface dis.placement during Holocene (la...r.t 11,(X)() yt::an;),

--------- $JJ4~ific Cn.teria---------

1. No structures for human occupancy are permitted on the trace of an acti\'e fauh. (llnless prolfen otherwise, the area \\·ithin 50 feel of an active fault is presumed to be undcFlain by an active fault).

2. Requires geologic report!, directed at 1he problem of p0ten-1ial surface fauhing for all projects defined by the Act (Sec­tion 2621.6).

.3. Requires. that geologic rcporlS be submitted to the St~te Gc:ologiSI for open-file.

4. Require'~ cities and counties. to review geologic repons. for adequacy.

5. Pernlits cities. and c:~lurlliC"!i to establish standards rnore re~ strictive than lhe p01icies a1id criteria.

b. Define:;, (a) .. projecr." (b) struc-ture for huma.u occupancy, (c) nc,,.,· real ~tnte developnient, (d) story, (e) conversion of a slruclure from one use to another.

7. Indicates. that s1a1c and rcgion;-1.l agencies having. approval au1ht1rit)· for )'lrojects. should comply with the Ac1 and the Policies and Criteria.

PROGRAM FOR ZONING AND EVALUATING FAULTS

Requirements of the Act

SC"~lion 2622 of the AlquiM-Pl'iolo Special Studies Zones Act (Appendi~ A) requires the State Geologist 10:

1. "Delineate ... appropri~tely \\'ide special studies zones to en·

Andrea~. Cala.vcre.s1 Hayward, and San Jacinto F;tulls, and such 1..~ther faults. or segn1cnts thereof •. as he deem!. !;uniciently active and well-defined as to constitute n po1ential ha1.ard to structures from surface faulting or fauH crei:p."

2. Compile maps of Special Studies. Zones a.nd s.ubn1it such mar~ lo afTected cities, counlies, and s1a1e agen.-:ies. for their review and comment. Following a.pptopriate reviews, the Stale Geologist musl provide Offi~ial Maps to the affecled cities, coun~ ties, and state: agencies..

3. Continually review new geologic and 'SC'iSmlc data in order to revise the Special Sludies Zones or delineate additio11a.l zones.

1'hese requirements constitute the basis for the State Gcolo· gis.t's fault-zoning progn1m and for many of the policies devised to implement 1he progr~m.

Progrorn for Zoning Foults

As required under the Act, the Slate Geologist initiated a program early in 1q73 to delineale Special Studies Zones. to encompass potcnti;:1lly and recently active traces of the San An· dreas1 the Calavt'!ras, the Jia.yward, and the San Jacinto faults, and to compile and dbltibute maps of the~e zones. A project tean1. headed by this writer, v.·as e!.tablished wi1hin the Divis.ion to develop and conduct a rrogram for delineation of the zones.

Initially, 175 maps of Special Studies Zones \\'ere delineated for the four named faults._ These zone n1aps, issued as. Prelimi· nary Review Map~. \\.'Cte dis.1rlbuted for revicy.· by local and state governn1cnt agencies on Oi=cenlber .31, 197 J. Following pre-

. scribed 9Q...day review and rcvis.ion reriods, Official Map~ were i<Sued on July I, 1q74, Al that time, the Special Studies Zone> bc,sme effective. and the arfec1ed cities and counties were: re­'1~1ited to implement programs to regulate development "·ithin the nlarped zones.. A second $.Ct of Official Maps~Sl rru1ps of t1ew zones and five n1ap~ of revised zones~was issued On Janu~ ary I. 1 ()76, to dc:line;:1le new and revised zones. Addirional Official Maps of new as well as revised z.ones wi:rc: issued each year. generally on January 1. follo\\·ing the ii-suance of Prelin1i­nary Review Maps on July 1 of lhc preceding year. Table 3 su1nmarizc~ the dales and number of nc¥.: and rcvis.ed Official Maps issued.

Table 3. Officio! MopJ of S~ial Sluditll ZOMS

l1s1J~d 01 of January I, 1980.

Del~ af iJ:J.u~ N~-w maps k~-.is~d tnCJps

July I, 1974 175 --January 1. 1q16 81 ~ January I, 1977 4 3 January I, 1978 1 --Jul)' 26, 1978 2 --January I, 19n 4 7 January l, 1980 11 9

Totals 288 24 • compass alt potcnlially and recently active traces of the San

NOYatiJer 25, 1985 Page 30 of 36 1980 FAULT-RUPTURE HAZARD ZONES IN CALIFORNIA 5

Definitions, Policies, Rotionale

• In order for the State Geologist to carcy out his mandate to establish regulatory zones. cenain terms identjfied in Section 2622 of the Act had to be defined and p0licies had to be devel­oped to provide a consistent and reasonable approach to zoning. After the zoning program Wa5 undeN'ay and the surface fault­rupLurt: proc1:5s ~·as. better understOl.'td, other terms were defined anJ wm.e zoning polic.:i~ Wt:"re mod1fi~d.

Fault and Fouh Zone

A faulr is defined a..~ a fr:icture or 1.0flC of closely associated fractures along which rock~ on one side ha.,.e b<=i:=n displaced with respect to th~ un the other side. Mos.l fauhs are the result ~)f repeated dii;placemeut which may have t:'.1.ken place suddenly and/or by slow creep. A Ji.Ju/t zone is a zone of relat~d fauhs which commonly are braid~d and suhparallel, but may be btanc:hing and Jjvergent. A faull zone has s.ignificanl widlh (wilh respcc1 to the scale al v.·hich the: faul! l$ being considered, ponra)~d. or in·•~~tigat~d), fanging l"roin a few feet to several mil~,

Fcult Trace

A liu1/t tract! is the: tine rorm.M by the intersection of a fault and th1: eanh·s 5urrace. It Ii the representation of a fault as depicted on a map. in1.:ludlng maps of the special S\udies. zones.

A~tivt!' fovlt For the: pu~ of this Act, an actiYe fault is defined by the

.late Minin_s and ~eology Board ~son~ \\'hk:h has. ··had surface d1spla.cement v1ri1h1n Holocene time (abou1 the last 11.000 year.>) .. (sec Appendi" B, Policies and Cri1eria, item 3). This dc:finilion docs no1, of cour~1 mean that fault'.'! having no e:viT de::JH,;e ror surface displacement within Holocene tin~e a.re neces­sarily inactive. A fauh may be pres.urned to be inactive hased on sati:.fi,u;:tory geologii; evidence; howevt!r, the cvidenc:i:: neces~ary to pro-ve inactivity is diffiL·ult to obtain .and locally may not exist. The Board"s definition or an active fault '"is intended to repres~nt minimum criteria only," and local jurisdictions "may wish to

impose more restrictive definition!. requiring a longer time peri­od of demonstrated absen~ of di!plac:~ent for critical strue-1urcs." The Holocene ~finition of active fanlt is useful to local governments who must require site investigations ~fore devel­opment permits are used. It also serves 85 a basis for other definitions and for policies of the State Gcologisr.

Polttnlially Acfivtt foult Because the Alquist-Priolo Act rcquir .. the State Geologist

to establish Special Studies Zones to encompa.!js all ··p0tcntially and recently active" !races of the Si:tn A11dteas, Calavetas, ltay­we.rd, and San Jacin\o fauhs., ~dr.1i1io11al delini1ions were needed (Section 2622). Faults were defined as pal<nfla!ly 8<'ti•e, and were :zoned, if they showed evidence Of surface displacc:men1 during Quaternary time (last 2 10 3 million years, Figure 2) _ E;\ceptions were made: for certain Qua1c:rnary (i.e., Plicistcxene) faults that were presumed to be inactive: based on direc1 geologic evidence of inactivity during all of Holocene: llmc: or longer. 1'he term "recently ac1ive" wa~ not defined, KS it was. con~idi:red to be: covered by the term ··potentially active."

Suffi~1~nf/y Acti~ and W~!l-d~fintJd A major objective of lhe D11,·b,1on·s continuing fault zoning

and evaluation program is 10 e\'aluate the hundred!i of remaining potentially active: faults in California for zoning c:ons.ideraiion. However, it became. apparent as the program progressed that there are so many potc:nti::ally active (Le., Quaternary) faults in the State (Jennings, 1975) ihat it would be meaningless to Lone them alL In late 1975, the Siate Geologiot made a p01icy decision to .ione only those poten1ially active faults that have a relativt:ly high rotential for ground rupture. To facilitate thi~ the terms "sutf1ciently active" and ··well-defined," from Section 2b22 of the Act, were defined for application in zoning faults other than the four named in the: Act. These two terms c:onsdtute the present criteria used by the: State Geologist in dctennining if a given fauh should be zoned under the Alquist-Priolo Ac-t.

Sullici~ntly a.ctiv". A fault is. deemed sufficiently active if 1here is evidence of Holocene surface displacement along one or more of its segm1:nts or branches. Holocene surf.ace displacement may be dirc:c:tly observable or inferred; it need not be pr~t c:-very· where along a fault to qualify Iha\ fauh for zoning.

GEOL.OOIC Mo YEARS 6EF0FIE. ... Period Epoeh

·111i.1 .. 111:"

, ..... ~~~ l,)1.JAl"ERlllAl~V

~ t"t<~·~n.;: ..

i1 ~

" l"lllN:lt"nlt"

fl:K11ARV

rr~-i•li .... :~rw

ff""·~·t-1'-!0l:UtC 11111t'

• ....__... lk•t-mnm*' •ol j\·1>1+o;1~ um~

PRF:.SENT {•sl1r't'l,.~edJ

~Ill.)

II.Ill.Ill

~.111.ltl,IKXi • J,uuo.ooo-

7,Ulltl,llllO + 10,000.tJOO-

n"i.,11tM1,uno

: -.l.1.1Hl.lltKl,lltKl ....,.._

Faulh along which ma'<!'emenf hen oc;~

}

duriflQ thi1 ift~ ~ d.fin9\'I as (IC/i'f'fl by Pl)liciet and Crit.rio of tM Stat. Mining

and G°""""' 9-d.

Foult:1 d•fiMd a1 p0t-Htio/ly ~ far th. purpot• of 111TGiuafian few poniW.- zono. ..._

le

•

•

6 Jlr~[.::-t:~iar"J!!:-o.-----.....,cc:xxr:rn1F'tv:JlkrlNll'lliAi.'1DiilViVISION OF MINES AND. GEOLOG y SP 42

"'~IHkfint.-d. A fault is Considered wcU--de:lined if its trace is clearly detectable by a trained genlogist as a physical feature at or ju5l bcJow the ground ~urfacc. The fa.uh may he identified by direct Cl~rvation or by indirect methods (e.g.1 geomorphic evi­dirncc or gcophys.ical techniques; Appendix 8). The critical con­sideration is tha1 1hc fault, or. som~ pan of it. can be located in the lield with sufficient precision and confidence to indicate that the required site-s.pccif-.c investigations. would meet with some: suce~s-

De1ermining if~ r~ult is ~ufficiently active and well-defined is a mauer of judgment. How·ever. these definitions pro,,.idc standard. workable guidelines for establi~hing. Special Studies Zon~ undC'r 1he Ac:1. More precise meanings of these terms should dc ... elop a~ more is learned aboul the techniques of e ... alu­a.t;ng the hazard or surface faulting.

The evaluation of faults for zoning putpOS-e!i. i~ done with the realit.ation that not all active fauhs can be identified. Further­more. certain faults considered to be active a1 depth. becaus.e of known ~eismic activity, an! w poorly defined at the surface that zoning is. impractical. Although the Map Explanation (figure 3) indi1,,·;ui:s lhat "rotentially aclive" (i.e., Quaternary) fauil:io arc- idc-n1ili.:=d ~11\d zoned (\~.:ith exception~) on the OlTi'"ial Map~ ofS~i;i;.iJ Sn.1d1es Zones, 1his is basically true· only for tht:isc- ma~ issued July I. JQ74. and January 1. IQ76. Even ~o. all of the rrint:..·ipal fa.ul!:i.1.oned l1\ lfl74 and ]Q76 were active during Hok>­t.·~nf: time. if not hi~iorically. Beginning wi1h 1he maps of Januaty I. IQ77. al\ l"auhs zoned meet tbe criteria of ··sufficiently active and well-defined.··

Delineating the Special Studies Zones

Sf)f.-"i,;ial Studies Zone!' arc delinc-.ati:d on U.S. Geological Sur· "'C'Y IC'>pt'!~Japhic ba~e map!' al a M""ale of l'.24.(00 ( i inch equals 1.0CIO ri:t:1). The zone boundaries arc s1raigh1-line 'ieg1nents de· fini:d by turning poin1s (Fiiure J). M~1 or lhe turning points arC" inl('nd~d lo 1.:oincide with lot:..·atable fc;:11urt::!7. 011 1he ground (~.g .• lxnt,;h 01;,'irks.. roads., strea1ns). Nei1her lhc: turning points nor th!:! connt:t.:t1ng .zone boundaries have been surveyed to verify lh~ir marped Jot,;oUiOrlS..

Lll\'.J.lilHIS of Spcci;;il S1udies. Zone boundaries are controlled hy tht: ro~i1ion of fauil 11-01ces. :r.hown on the Official Map.~ of Spe~i;.il S1uJies Zon~. \\'ith fC"w e~c-ep1ions.. the faults sho\\'n on the 1q.74 and IQ7b Special Sn1Jies ZCloes milps were nol ficld­t,;h«ked durin[? the compila1i~1n of 1he:r.e n1ars. Howcv('r, all fauh:io toned ~ince January I. 1q.11. ha.\ie been field-checked to \·enfy that lht)I do meet the criteria of sufficiently active .and ";cll--dt.'.'fined. Zone boundaries on early maps were prni;i1ioned about bbO feet (200 meters) av.·a~ from the fault traces 10 .3.c~ cOmf.ldate imprei.:isi: hxa1ion:r. of the faults and po~siblc e~is.1ence of ac1ivc branch~. La.ter zones are narrower, and some :ione bouodari~ have been positioned as close as 200 to 300 feet from well-identif.eri traces..

Fault Evaluation Program

Tbe Fault Evaluation Program was initiated in ~rly 1976 for 1hc pu~ of evaluating th~ "other faults·· identified. in the Act as "'sufficienrly acltve and well-defined'" (see driinitions above) after it was rccogTiiZed that effective future z.oning could not rely solely on the lirnilcd rauh data of others. Ju:siification of this program Is discussed i.n more detail in Special Publication 47 <>f 1he Californi• Division <>f Mines and Geology ( 1976; also ... Han. 1978).

The program was oriiinally scheduled over a ten-year period. The state was divided inlo ten regions or work area5 (Figure 4)t with one region scheduled for eYalualion each year. The fauh evalua1ion work includes limited field mapping a.nd the interpre­tation of aerial photographs, as well as the use of other gcoloT gists' work_ A lisr of faults to be evaluared in a 1arget region S!!i prepared and priorities assigned. The list includes potentially active fa.alts not yel zoned. as well a..11. prrvjously zoned faults or fault-segmenlS that may \\'arrant a z.one revision (change· or d~\ction). For e.a(:h rault an ~valua1ion rerort (FER) summt1riz­ing 1he dal.4t on location, recency of activity, and :t;.en!'i.e and m<1~11ih1de or d1splace1nen1 i~ pre-rared. Zoning. rcc-ommtnda­tion:i. a.re made in each FER. Tht'Se in~house r-:port!i ate Died at the Divis.ion's. San Francis.co District Office in Room 1016 of the Ferry Building. \\'here they are available for rcfc-rC"nci:.

Evaluation~ for 1hi: firs! lhree reginns--d~ignated 1976, 1977, and 1Qi78 on Figure 4---have btt'n con1pletecl. Work in the 1979 area, currently urid1;t'\lo'<I)', has been e~lended one year, and subsequent work abl'I will be dela~·eti one year. Result'!' of 1he work done in e::ich rc-~inn are "S.Urnrn:tr'i:t.ed in open~flle reporls hy Harl and othc:r- ( 1q77; 1978: 1979). Th~e reports are avail­able a1 a nominal c:os.t from lhe San Francisco Di~trtc:I Office (lnfonnation Desk) only.

As. a result oflhe fault C\";du.a.tio11:-. r11:1.dt: during lhe fi~t three years of rhili prog.ram, 28 new i.ind 16 rcvio,;ed f('ne mars were issued 1n 197&. JQ7Q, and IQ80 (Tahlc- 3). If is nore,vonhy that the m;.ijori1y of evaluated faults not prcviouo,;Jy zoned did not mecl 1he criteria of "s.ufficiently acti\'C and Q,'ell....<Jefined'" and were lherefore not zon~d. As poin1cd out earlier, the fa.cl that a. fault d0t;~ 1~01 meet these criteria docs not mean thal ii is neces­sarily in~cli\·e or lh:u ii is free of [!.round rupture haia.rd. Some of the fauhs rio1 z:or1t.'d, even some that "'·~re not C\':.tlua1ed at all, nlay h11\c ~urface n.1plure in the future. For the mo~t part, such faultin~ j, c'ipi:i.:ied lo he minor, both in amount of di'.1.plaeemc:nt and in \englh nf'.',urface rupture. So far this expt-cl;Ili(>n has been borne oul by 1hi:= ground rupture events that h::ivc occurred since 1976 (Tobie 5).

Why arc some oiLli'>·e faults not Zl'ned or not even evaluated? For one 1hing. !tOT'llc: (41.ults lie in remote area~ 1hat ha1,·e nol yC"t heen mapped in dc1ail. 01hi:1 fauh!ii .;ire only slightly active and ~re UilTii.::ult to distin,suio,;h from inai,:1ive faull~. becau~~ the sublle fc;.uures. fornted as a ri:~uh of faulu1ig are ea~ily obliterated by gc~'llogk processes (erClsion. scdimt;nlat1on. ma~s wasting )or t~e activi1i~ of ma1i. Even lar_g:e-1"-C"le f"~ul1-rup1ure can be ob1;.cured in complex geolol!it:..· tc:-rrane"'S. (~r in "h1g.b.....ener.~y" cnvironmenls. Moreo\·er. fault rupture of1~n is compl~x. consisting or num~r­ous rauhs or u·arps di~1ributed in broad zones. of deformation th:it are difficult 10 di:lineale or c...-i\u;.uc. Mo~tly, such faults are poorl)' defined al 1h~ ~urfac~. Allhough. in a::onducting th~e fault evaluation and zoning acti.,·i1i~. the S1a1e ·GeologiM a.nd Division staff do e\"erything pos.:;ihlc 10 int.ure 1he safely of lhe public from 1he hai41rd of surface fault-rur1ure. there: are limits to what can be done and they 1ihnuld be recognized.

Because of the difficultie-s in C\'"ah.uuin~ faults, eilh~r for ion­ing nr site dc...-ck>pment purposes, e:uidelines ~·ere prepared to a~sist olhcrl- in these evaluations. ThC5e guidelines appei!.r as Appendix C. ··~

Uses ond Limitations of Special Studies Zones Mops

The Spttial Studies Zon~ are delineated to define thC't!iie areas within which special studies are r~quired prior to building struc­rurcs for human occupancy. Traces of faults are shown on the

(.

1• I

•

10 CALIFORNIA DIVISION OF MINES AND GISOLOGY SP 42

rn:ilpS mainly.lo justify 1he locations of zone bounde.ries. These re.uh tr.ace~ are plotted as a~C"uratcly as the sources of data rer· mit: ~·et the plots are not sufficiently accurate to be used as the basis for set-b<iCk requircn1cnts, and they should not be so used.

The State Geologist has identified active and potentially active faulls in a broad sense, and 1he evidence for activity of som~ fauh&. may be weak or indirec-1.

The fauh inforrria.hon shown on the maps is not sufficient to meet the requiren\ent for special studies. Local governmental units must require the developet to evaluate specific sites within the special studies zones. to determine ifa potential hazard from any fault, whether heretofore recognized or not, C1iiSts wilh re­gard to proposC'd structures and their occupants.

The surface fault rupl urcs associated with historic earthquake and creep even•~ arc: idcnlified where known. However, no de­grc-c of relative polcnlial for fulure surface displacement or de~ grcc of hazard is implied for the faults shown. Surface ruptures resulling from 1he secondary effects of seismic shaking (e.g., landsliding, differential settlement, lurchiog) a.re omitt.cd from the map and do not serve as a basis. for ioning.

INDEX TO MAPS OF SPECIAL STUDIES ZONES

The following pag~ (Figures 5A lo 5G) indlcale the nan1es and locations of 1he official maps of special sludies zones deline~ ated by the Califoroia Division of Mines and Geology uoder the Alqui~t-Priok1 S~ial Studies Zones Act of 1972 (Appendi~ A). The!'le index pages idcn1ify all Official Maps of Special Stud­ies Zones relea~ed hy the Slati: Geologist 1hrough January 1, 1980. The official maps are compiled on U.S. Geological Survey 7.5~rninure topographic quadrangle: maps at a scale of l inch equals 2,0CXJ feel ( figl1re)), Cities and counlies affected by 1hese mars are HMed in i·able 4.

Hec.aus.e Special Studies Z1..'lnCS. maps will be issued apriroxi­malei)' once a year to delinea1c revised and additional .zones, users of lhes.~ maps should ch(;".,;k with the California Divi!".ion of Mines and Geology for up-lo-date information on new and rc:\·ised Special Studies Zones maps. A change in .zones also may aITcc1 different local governments. This index 10 Official Maps of Spec:ial S1udic:s Zones (Figures 5A to 50) will be revised in ru1urc years as new maps are issued and other useful data becomc- available.

The: Special Studies Zones maps are available for rurchase as indicated under Avail3bilit~ of Special S1udies Zones Mar!".. Also, they may be c:on~ultcd al any office of the California Division of MinC5 and Geology, at several State and local librar­ies, and locally at the planning departments of all cities and counties affcc:tcd by Special Studies Zones.

Avoilobility of Special Studies Zones Mops

Reptodu(;ihlc ma!;1Crs from Ythich copies of !~"!Cal sr~·cii1l Studi~ Zones maps (~calc 1:24iCKX}) can be made have been provided to ear:h of lhc cities and counties arrected by the zones. Reque!ots for copies of particular Speci.al Studies Zones. maps of local are.as should be directed to the Planning Direc­tor of the appropriate city or county. Refer to the index to srecial sludies. iones rnaps for the quadrangle names of the maps needed.

Arrangen1ents also ha\le been m~dc wilh Blue Print Service Con1pany, San FrancisC"O, to provide blue line copies of the Special Studie!". Zones maps to those who can't get them conveniently from the cities and counties.

Blue Print Service Company 149 Second Street San Franciscoj CA 94105 Telephone' (415) 495-8700

Each mar mus.I be ordered by quadrangle name as shown on the index map. The cost of the maps is nominal, a.Hhough there is a minimum charge; handling and C.0.D. charges are exlra. These maps are not sold by the California Division of Mines and Geology.

REFERENCES

Colifort1io Divii.ion of Min~$ and Geology, 1976, ,._diwe foult mi;tppin~ (Jr'ld evaluation progrc=Jm - 10--yt!or progtom to implement Ali;iu'11.t-Priolo Spe<:ii;it Studi1u lon~i Ac11 Californ.ia Oi11i1.ion af Mine1 and GeDlogy Speciol Publication '47, .42 p.

Hort, E.W .. l91B. 2.oning far the hazard of 1urfoce fault rupture in Coliforriio1 lnl~rnatitinal <;:onler~nce On Mi(:rOl'li);l)l!Qn, :2nd, $gn frgnciii;o, 1978, Proce!'ding1. v. 2. p. 635--646

H~ul, E.W., 8Qrtu~nQ, f.J., 1;mi;I Smilh, T.C., 19'7, Summary report~F"1,1lt Evaluation Program. 1976 a1eo \Wei.tern Tron1.ver$e Rc;;g~•) 1 Colifornia OiviiiQn ol Min•i gnd CeQIQ~Y Opwn File Sleporl OFR 7? -8 SF, 13 p., 2 pl.

Harf, f,W., Smilh, O,P,, Qnd Soul, R,8 .. t979. Summary r•porl - F1;1ult Evaluofion Prog1om, 1978 ort!o (Penlt1i1,1lot Ri:ingei. - :Sol1or'I Trough r!'gionl; Califorl'lia Oivi•ion of Min.el and Geology O~n file lfeporl OFR 79-10 Sf, 17 p., l pL

HQrl, f,W,, Smith, O.P., and Smith, T.C., ~91'8. Summary r~po1t - Foult

Evoluotion Progrom. 1977 oreo (Lo!. Anliel•1 ba,in region) 1 ("(llifi;i,rnic:i

Diviii(m ol Mine1- and Gealog)I' Open file li:eport OFR 78-10 SF.

l6 p .. l pl.

Jenniri91. C..W .. 1975. Foult map ot California with i(l(:Otioni. ol yok.onoei, thumQI iprin~i, ond thirrmQI -wislli; Colifomio Oivi1ion Df Min•• o"d Geology Geolo.gii: Dalo Map No_ 1.

!liOTK Rf'l°f'rt"n~ 1.J"l"d II• ("l.•rii!)1k f1111lli on v.-hld1 th~ SP"Ci...J S1udie1 Zonr-1 Uf'

b...H'd 11rf' li11t"d on the indi\·idu11.I Otticial ~hps

DATE

TO

SUBJECT

•

Burkhart ~ 25, 1985 Page 33 of 36

PHONE 7367

LAND MANAGEMENT DEPARTMENT STAFF

ALQUIST-PRIOLO REQUIREMENTS

It appears a modification of County Alquist-Priolo Policy regarding land divisions involving large parcels and proposing three or fewer single family wood frame human occupancy dwellings of two stories or less would result in significant savings to developers. The previous County policy required a geologic report over the entire land area for any "project," including a lot split, within an Alquist-Priolo Special Studies Zone. Some minor parcel lot split "projects" were required to investigate large land areas where only one single family, wood frame "human occupancy structure" of two stories or less was proposed. In some cases, geology consul­tants were not able to fully investigate the "project" because of very steep topography where building sites may not have been feasible anyway because of the topography.

In order to make County policies economical and practical for field implementation, the attached Land Management Standard Procedure and Policy will be effective immediately.

JNJ:LB:sg

Attachment

cc: John Jaquess Clark Alsop Larry Schoelkopf Steve Wilson Claude Tomlinson Larry Cotton Pat McGuckian

• NoVelter 25, 1985 Page 34 of 36

County of San Bernardino NO.

EPW A/Land Management Department EFll"eCTl'Vli!

ISSU&

PAGE 1 OF 3 AEVISEO

STANDARD PROCEDURE !-....:>"'-~-=,...,,..,=""""=-~~~~~~~~~~~~---IAP.P~CV~D .JOHN N. JAQUESS, DI rt ECTOR

OFFICE OF PLANNING SUBJECT QEOLOG

STUDY REQUIREMENT

POLICY: When parcels are being subdivided within a "Fault Hazard Special Studies Zone" and three or fewer single family, wood frame "human occupancy structures" of two stories or less could be built, a geology study that can demonstrate a "suitable building pad(s)" will be an adequate alternative to a study of the entire parcel area, subject to the following procedures.

DEFINITIONS: 1) "Project" - Any structure for human occupancy or new real estate development as defined under Section 2621.6 of the California Public Resources Code.

PROCEDURES:

2) "Structure for human occupancy" - A building, as defined by the Uniform Building Code, which is expected to have a human occupancy rate of more than 2,000 man hours per year.

3)

1)

"Suitable building pad(s)" - A building area with a minimum SO foot safety factor as demonstrated by direct observation of continuously exposed geologic units and features which must be carefully logged (see Taylor and Cluff, 1973, fault activity and its significance assessed by exploratory excavation, in proceedings of the conference on tectonic problems of the San Andreas Fault system: Stanford University Publication, Geological Sciences, V.XIII, p. 23 9-24 7) •

A geology report shall be submitted for review pursuant to Alquist-Priolo Special Study Zone requirements. The geology report shall include a site map showing the location of the trench(es), the proposed building pad(s), and the distances to the existing survey monuments. The site map shall designate: a) the area(s) investioated for placement of single family, wood frame "human occupancy structures" of two stories or less, b) the area(s) requiring further geologic study and cl areas of oeolooic hazard (i.e.: active faulting) not suitable for placement of "human occupancy structures." The ends of the geologically logged area (i.e., trenches) and limits of faulting found during the study must be

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Noverld:>er 25, 1985 Page 35 of 36

NO. ~

"' ..,.. -, County of San Bernardino ki&. ' EPWA/Land M•n•90ment 0e!l"rtment

issue PAG~ 2 OF 3

REVISEO · ..J• EFFECTIVE . STANDARD PROCEDURE

1--....:.·~'~~~~~~~~~~~~~~~~~~~~APPROVSC OFFICE OF PLANNING

N. JAQUESS. DtAECTOA

susJECT GEOLOGIC FAULT HAZARD STUDY REQUIREMENT

2)

3)

staked by the geologist r reference during the survey by a person authorized to do land surveying. The results of this survey shall be modified by the geologist to precisely delineate the three site map areas [a) area(s) investigated, b) area(s) requiring further geologic study, and c) areas of geologic hazard] and shall be submitted to the County as a supplement to the geology report.

Prior to conditional approval of the minor subdivision the Geologic Fault Hazard Study and supplemental survey map shall be approved. After approval of the study, any resulting conditions shall be incorporated into the minor subdivision conditions of approval. A standard condition for all such minor subdivisions shall require the parcel map to delineate in the DEVELOPMENT NOTES under GEOLOGY that "a specific buildable pad area has been geologically investigated on this parcel. Refer to the Geology Report on file with the Office of Building and Safety."

The delineated "Area Requiring Geologic Investigation Prior to Building Human Occupancy Structures" only applies to structures for human occupancy and shall not affect al legally constructed existing structure(s), orb) additions or alterations, t'O""existing structure(s) which do not exceed fifty (50~) percent of the value of the existing structure per Section 2621.8 California Public Resources Code (Alquist-Priolo Special Studies Zones Act). New construction of a human occupancy structure(s) within this area shall not be allowed unless an additional geologic report for that area is prepared.

If a human occupancy structure is subsequently proposed in an "Area Requiring Geologic Investigation Prior to Building Human Occupancy Structures" the applicant must have an additional geologic fault hazard study prepared for the proposed building area and have it submitted to the County's Engineering Geologist for review and approval.

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Novaitier 25, 1985 Page 36 of 36

NO. ..,.... County of San Bemardino

~ EPWA/Land Mana!jllment Oepartmont EFFeCTIVe

ISSWlli.

•AGE 3 OF 3 R~v1seo

STANDARD PROCEDURE .;.- A,_...AOVEC

f---""'~---,.,,....,nm:rn:TT!""~~~~~~~~~~~--i JOHN N, JAOUE.SS. 01 RECTO A

OFFICE OF

SUB.IE CT

STUDY REQUIREMENT

BACKGROUND: Previous County policy required a geologic report over the entire land area for any "project," including some minor subdivisions, within an Alquist-Priolo Special Studies Zone. Minor subdivisions involving three or fewer lots were required to investigate large land areas where only one single fa.mily, wood frame "human occupancy structure" of two stories or less was proposed. In some cases, geology consultants were not able to fully investigate the "project" because of very steep topography wher~ building sites may not have been feasible. The policy change was made to make field implementation more economical and practical •