California Geology Magazine May 1990

CALIfORNIA GEOLOGY slall

120120

9899

107...... 114

.... 115116

"'120

~PITTSBURGH

~--

ALG. Mb\-IS"0 Bu, ~7n

Green,hurl!.I'A 1.'i6(H(412) 8.\6·681 ,1. (800) 34.\-~12'J or

18001 J4!-167J r,n PA) ')01'

Ttl rec"'le a b.(\("hurc and ."f"rmatlllll forrel,'I'lrallun ;lnd ,'~hlbl1' conl;ld

ar" "I:.n, ,runmemal App!I"all"n~of I:.nl:'l­nee"n!! GeOllh)'Ic' ": .. ApplIcatIon' ofMlcrocompul<·r, I" Rud SI"P<' SI;lhilil),\nal)",,.: ,. ,\n Imroducliun w Geu') nlh,'I­'''' S"I('('I;un, l)e\l1ln & Applll'allun, lU

W;"re l'a('illlle,"; anll "SI1<' Chara<·,erl/all"nfor NIKlcar Wa,le D"p">'al ..

On Tue,da). Oelober~. 1990. the l'enn')I­'ama Geol,,!!i<·al Sutle) and Ihe Allc1lhen)Olu" See1l0n "f Ih<' A'"Il.·, .• lllln "f l:n!!lnecr m!!(ieolulZ"I' "" til 'ptm"" :1 on<'·<.!a) lea<·he~'

""rhh"p In .'''nJune!;on "lIh Ihe "nnualmectrn~.

In addu"", I" lhe lcchm,'al pW1lrall' ,,·he<.!·Irlc. a full rail!!" "f 1luc" acllVl1le,. 'vcctale\enl,. and fldd Irlp' hah' I...<'n planned 10

hrin!! all<'nd,"" IUI!,·lh"r

The ,\kelin~ ""III feature alt Jo,lnhlll'r..·1lram "llh O\-;:r 55 eOrnpanle' parlK,pallnl!The e~hlhrl ar.'a I' cer\lrall) h>calcd 10 allmeclrnl:' and funell"n room,

AEG 33rd

Annual Meeting

COYtI. P.renn'olly ochWl lond.llde along Srore HlghWQ)' 16 o!ltte ColusoCo.ul'lIy·Yolo Counly bo.der The bedrock conSlI1's of shale, mudsrone, andInlerbedded sOl'ldstone olltte FISke Creek Formor,on [Upper CretoeeouslThe onglnol cause 01 the landslIde was from entfenChmenl and undercuttingby Coch. Creek Outing heavy rains rock deb..s coverl Stote H,ghwoy 16 atlhe bose olltte O\Iet1teepened slope and IS soon remoWld by molntenoncecr.....s lrom the CollfornlO Deportment of Tronsporlotlon Note the d,m'nuliv.SlZ. 01 rhe removal equIpment 01 rhe bose of lhe slIde. An artIcle oboulltteIand.llde potent,ol;n lhe o'eo 01 Cache Cr..k beg,ns on poge 99 Photo byMW Monson.

ASSOCIATION OF ENGINEERING GEOLOGISTS.33RD ANNUAL MEETING '

LANDSUDE AND FLOOD POTENTIAL ALONG CACHE CREEKGEOLOGY OF AN AREA IN ALTAMONT HilLS. DIABLO RANGESOURCE MATERIALS FOR EARTH SCIENCE PROJECTS ...1989 - SIGNIFICANT EARTHQUAKES .BOOK REVIEWSMAll ORDER FORM .DMG RELEASES ,

CALIFORNIA CONTINENTAL MARGIN GEOLOGIC MAP SERIESMAP NO.4 AND MAP NO.6 ..... ,....

CALIFORNIA GEOLOGY SUBSCRIPTION FORM

In This Issue I

T"" ')I11I"""a ha\e been ,<'hedulcd On"')lltpt"IUItl ,,"III Include .12 pape" on Ihe";lIe-ol-lh('·arl r."di<·lum aoo conlml oftlllnC 'ub"den,·c The olher ')ltlpt"IUItl "tllmelude.\O p"p"r, add.e)"n!:' "'lie' .e!:,ardrnl:'Ihc hl'l"ry 1I1. n""d f"r. and currenl 'lalu' "fpruk"'unal rCl:'''lralllln for !!eUh1l:'''''

fhe ,\ Itel!hen~·Ohu' Secllon "f the ,\"".l·lattUn "f I n1llneerllll:' Gelllu~I,I' IAI:.Gl '" IIIh,"l the .11rd Annual Meelln~ uf Ihe '\"IJoCla'l1"n of I:.nl!llleerrnl! G,,"I0l:'''h on OcloberI ~. 1l)<J(). In l'lIhhurl:'h, p,'nn,)h"nia Th"lhem,' "f lhl' nal11ln,,1 meelln!! I' ··"nl:',neer­Inl! Geol"l:') for Ihe IKl\ ., The p"'j!rarnInclude' lel'hmeal '''''llIn,. ,~mptl'la. anti,hUrl '·lOur,e,

hour half-day ,h"n <·"UP."" arc \Chedulcd,·on.'urrenl ",Ih lhe annu,,1 rneellnl:'. They

T,'ehnleal ,e"lOn~ ,,"111 f.II;U' "" applIedelllironmenla! and l:'eol~leal ",ue' relaledlUII)IOe wb"denee. hillardou' ,,"a'le, IO\C,II'l:'"lltln and ."med,al,oll. emlmnrncnlal1leol·1'1;). l:'fUUntl ,,"aler. ,Iupt' 'Iabllll)·. dam,.~a"l. and ern"on 5e"u>o) an: bern1lplannell m lhe area, of dam foundall0n, anllrehahlilial u>n. appl) m1ll'umpUlcr-ha\CJ tel·h­nulu!!) lll!an(hhde prohlem,. rod ,lope,:n\er and la~e·,hure '1;Iblln) anll erO'lun:h)d"'l:'eol(~) and halardOl" "",,,It,; andpwolcm' of App"la<hl"n !:,,,ul.'I;)

Marye WoodsOon OUp/liS

Mary EI·BdourBruce Foggy.

Peggy WalkelJell lambert

JAMES F DAVISStale GeoIoQlSl

CALIFORNIA GEOLOGY (I$SN 002$ .~l .. p..ICIMIledmonlhly 1:>1' IIIe Depatl....nl or ConservalOlft 01V1SIO<'> orM,,," and GeoIoqy TlIt RlH;Ofds 011« .. al 172t·201t!Sir'"' s.cramenro, C~ 95814 5ecorIIfCllon poIl&{11I'pa'4 at Sacramento CA POlu".,ter S.nd add..11Cft&.11O CALIFORNIA GEOLOGY (USPS 350 8401,6oJ< 2980 Silerame.lto, CA 95612-2980

Ed'lor-,n·Ch'etEd,lorEd,lollal AsSistanceGlllphlCS and Design:

PublO<:81,ons Supervisor

RePOfI. conurnmg DIY,.lOn 01 M",el al"lCl GeolOgyp'Oje<:l,al"lClarrocle. al"lCl_ Ilem....aNd 10 the a.. ,t!IC>eno:es'" C&i~Ofn.a ... IncllIOell ,n lila magu..... Con·ltlbutS'd.,locJes pI'Iolll{llap!lS,_,t_ andgeologocal-'"II ..........ncllm.nlS a.. weIccIrM

THE CONCLUSIONS ANOoPlNI()NS EXPRESSEO INARTICLES ~RE SOlElY THOSE OF THE AUTHORSAND ARE NOT NECESSARilY ENDORSED BY THEDEPARTMENT OF CONSERVATION

SI..leoIC..,Iclf.... GEORGE OEUKMEJIANGovernor

CG(OA.3 (5) 91, 120 (1990)

Depatlmet'l 01 O_el Sfi"",..011<101 Slale Pf'''\JnlI

(l,v,_ l"eMquaflers 11'6 N,nm Street Room 13-'1,s.c••mento. CA ~l.(Tele¢ltlOne 916-445-1825l

P.mIlClIhO'" _ tnl"""""on OUlCe660 lIe<Cl.Jt Or"". SACfemen10, CA 95ol1U·013tCAt.lFOAN'I'.GEOLOGY 916-U5·0514Put*; Inlo<mallon 916-445·5716

Lot Mgoeles 0I11ClI , 07 Sou\ll 6rOlldw,~ Room 1065lOI MveleS, C.o.1OO12·••02(Tolepnone 213·620-3560)

P HIli Ollo;e 3&0 C'VI(: Of.... $on,.. 100Ple nt H". C~ 9.523·1921(TeJ&pllOne 415-M6-59201

.~LIFORNIAlj~OLOGY..~~

... PUBLlC"TION OF THEOEPARTMENT OF CONSERVATIONDIVISION OF MINES AND GEOLOGY

COfJ"POndance Inould Oe add..lled 10 Edll0'CAl.IFORNIA GEOlOGY &6OBetcutO<...... sa",amenlOCA 9581a-0131 (9161 445-0514

SUOIlC"puon. S1000 PI<,e" S'nore coP!" S' 00.act! SI!tI<l lI/OkI'.prOlft Older, and CI'Ia. 01 _as...IOlmatJon to CAUFOI'lNIA GEOLOGY PO 6oJ< 2980sac""""IO. CA 95812-2980

T.... Resource. Agerocy GORDON K VAN VLECKSecrerary for Resources

~nmetll a4 C-VIloon RANDALL M WARD(),eclor

98 CAlIFORNIA GEOLOGY lola, 1990

Landslide and Flood PotentialAlong Cache Creek

Lake. Colusa. and Yolo Counties. California

By

MICHAEL W MANSON, Geologistlandslide Hazards Identification Program

Division Of Mines and Geology

"

oo

<"~..

SAN FRANCISCO

SANTA ROSA

"UKI....H

ThtS artIcle was adapted from landslide Haz­

ard. o/otlg Ccehe Creek berwe"n Cleof Loke andCapay Vol,er. tah. Co/u.o. and Yolo COllntfllt$,

(olifo,n,o. DivISIon of Mine. ond Geology Open­F;la ~flpor189·JO llandslide Hozard Mop No.19, Kol.12",OOOI. The Iondslide invfl,l'90rionwoo ~rfo.med und", the lon,hl,de Hozord.Idenhfico!;on Program ILHIp) eslobl,s.h.d in 1983by the Colilornio legislature to ptovide inlorma_han 10 redu<e landslide hazard. ond propertylon4l1 in cleveloping oreOI. 10 Improve public"'/ely by identifyIng gre~. ,ubi_ClIO debri. flow"C1nd 10 d.....elop map' .howing landslide hOlord.for use by local government planners. The CacheCreek area" one of more rhon 20 Oreal withonCalifornIa mopped under this program (leeCalilornia Deportment of Conservation, 1988;Monson, 19890).

Tho study COVers geologic cond,tion, related toslolH' ,tabil,ty along Cache Creek between ClearLake and Copoy Valley 10 identify IOCOlrlletwhorelondsllde movement could rewl. in block.og. 01 Coche Creek in on event ,imilor 10 Ih"1906 landslide blockage ollhe creek.

The .rudy r"sul" can be u..d by local ogenc18'10 make land·u.. de<:lSlQlll and to prepore lormItigatIon 01 landslide hazards Ihot PO" a Ihreal10 public oolely. The campi.,. repon (OFR 89­30~ oneluding recommendation, IOf emergency~redn.tland planning lor mihgollon 01Iondslode hazards, will be available soon Irom 0"vlllOn 01 MInes and Geology, PublIC Inlo.mol>on,660 Befcut Onve, Socfomento, CA 95814·0131.

. .c/rtOf

F,gure I. LOCOhOn 01 Cacho Cr"ek and Capay Volley I ,n color) in centro! CoMofMlo Coos, Rang...

INTRODUCTION

At aboYI 9 o'dock on the evening ofn Tuc~ay. May 1. 1906. a ~lisht~htJ(:k was fell in Capay Valley. California(Figure 1). The great San Franciscoe:trlhquake had occurred only 13 day~ be­fore. and nOllOO mueh nt)(ice .... as gh'enco lhl~ rate~t shock. When the local cili­lens arose the next morning. however.they ....ere surprised to find that the WOllerlevelln Cache Creek had fallen consider­ably. Al GUllld... In the C..pay Valley. thecreek 1c\"C1 h:td dropped 5 feet overnight(Will/l'r$ £.fpr('$$. r906a: WrHH//wld fJlIily/Jel/1(}<'rtll. 1906).

Due 10 lhe rugged and remme nalure ofIhe C..che Creek dminage up~Ire..m fromCapay V.. IIcy. the cau:.e of the drop Inw..ter was not known until Thur~ay.M ..y J. 1906..... hen word W'h received inCapa) thai a larnbJlde h.uj blocked C..cheCreek below Wlbon Valley (Figures 2and 3).

The I..ndslide Ihat dammed CacheCreek was aboul 100 feet high and nearly500 feet wide on top (Willler.f £lpr/'ss.1906b). It wa, compo:.ed of debris frornlhe Crocl. Canyon Formation (Lo.... er Cre-

taceou~: Lawton. 1956) and impounded3pproxin13tcl) 12.000 ..cre-feel of water(SCUll. 1970) In a lal.e that e."cndedabout 4 miles up~treall1. No attempts .....eremade by local authorities to removc theob~truclion due to difficult acccss 10 thisremmc location. I n anticipation of aflood. most of the fesidelll~ in the upperC..pay Valley evacualed their homes andc..mped out on nearby hill~idcs (PhotO I).

When Ihe dam faIled five days after theI.. ndslide created 11. the re~ulling floodelllered the Capay Valle) and dcvastated

CALIFORNIA GEOLOGY

thc small toy,n of Rum~) (Figure II.destroycd sc\ocral buildin¥s. and damagedlhe count) bridge across Cache CrecL. andlhe SOUlhern PacirlC ratl facilities. Thef100d-walcr 1C\'c\ reached a height of fourfcci abo\·c the normal high y,alcr mOirlFortunately. no one was IOJured Of L.lllcd.Although the landslide and flood wcrementioned 10 lhe summar) reporloo lhe1906 San Francisco earthquakc (Lay,-.on:and OIhen.. 19081. il soon faded 1010 ob­scunty along Y,ilh many other cffecb ofthat great e\en!.

The following article by Ed E. Lc<lke.editor and publisher of the Willlers£,prt'ss. appeared in the May II. 1906i5~UC.

WHAT HAPPENED TO CACHE CREEK

The Grear Dam Goe. Out Ea.y and Nobody I.Hun ... Small Property loss or Rum.ey and lots01 uc<lemellt All AloI'Ig the Creek.

The grealllide in Coc'" Creek hos gone au!,ond .... ~ple of Capay "'CIlley hcrve "'tileddow-n tel normal conclitson" For fW. days ....,Mabdonts of t+>al beautiful "'CIlley w.r. unoder""- wspen"" ...peding haur+y rho! the damwavld gr-. way and Ihou.onck of 10M ol_erM pre<,polated dawn Ihe creek. .we'9'I'Ig 01before <l. The ...peeled ond leored happened'" 0I'lIy a small degree. Sunday noghl abous twoo'dock .... dam went, cutting away ,n th. c.nltlrand I.tt'ng oul the waler .Jowly. 01 coune a "'CI1Ia_nt of debris wenl dawn w,1h 'I, and Ih. cre1l01 the Rood was so covered w,th droftwood andIree. rho! even or Capay 'I looked like on. couldalmo.t walk acrou il.

PhoIO 1. XOI'p of .... 1906 landslide (cenler 01 pftotol_ Cache Cleek os,.,.1 au! 01 view at the ba.. ollhedifl. AIthovgh rho. slide occ.....red 8.. yea.... ago, .... Korp and slide mou of the Iand1lide on CacheCreel< or. shft d.....ncl rhelondslidec~n about 28 ocr.. and originally contoined 3.1 mil50n cvboc:yards of motenoilScOIl, 1970) Although !he subsequenl flood and !he damage it caused 10 dow-n­.lfeom commun,t,., were ..rious topoa. !h.. local c",zen, lound some humor on Ihe ..tuaIlOn. OneWoodland "are ron an ochrertlSemenl ,n !he Daily Democro' during the Wl!ek 01 May 8·1", 1906 lhotread ,n pan, "DANGER OF flOOD IS OVERl Not balhlng coslume bu, good kn,t underwear" thegarment now needed.H f'tto'os by M.W Man,on

The pronc,pal damage woo done at Rumsey, rhehead of the yolley. Troyis' hou.e woo wo.hedaway, lhe Earl Fruit Co'slooding shed wrecked,Ihe Southern Pacific pump hou.e corned up 10Ihe depol, all the yard track. dellroyed, Lloyd'sbarn com&d off, bath approaches 10 the counlybndge ocrO.. the creek deslfoyed and Ihe ..II.domog&d, and considerable ,nlury was done tosome orchards. The wOler went ,nto the depot,bul did no harm. II 0110 corned off J.M. Marron'.Slo•• and post office and wogon ....d, but .yery·thol'lg hod been moved OUT, 10 no damage wasdone to .....tock or the ma,l

Jo see IU1I what me conditIOn, w.... before thebreak rho ed,1or of the upreu mode lhe Inp 10.... sc.... of .... olide,leavtng Win'.n F...ooyfftQmIng at a moment'. nolK•. AI ModiK>rl, J II.Jones boarded Ihe troon, and soon modeo IIknown t+>al he was On the way 10 .... .Jide. MrJones hal much .tock on h.. form thor would beoffecled by a big ""h 01 water, and he wonled tosee what the donger was. So he and Ih. news­paper I'I\On mode a compact to go 'ogelher

ArriYlng 01 Rumsey, It wo.learned rhar Ih••I,dewaS probably twenty mil.. away, and Ihe counlrybetween Inacce."ble mountaIns, II one did nol

know rhe way. Those who hod rhe tnp ro makeunder normal cond,llonl followed up Ihe creekbanks, but 0' 'hellood was e.pected 01 any t,me,nobody wonted 10 go by Ihol roure

IA party of fi.... officlOl. from Yolo County)hod arrived thol morn'ng from Woodland. andtokong aU rho o"'CIilobl. ha...... and two or threegUIde. le' out lor the dam belore the Ifoln.......

Mr Janes e"pec1ed 10 mak. the trip on 1001,but the dislOnc. was roo greG!. and beong WIOC·CU1Iorned to horseback nding he decided to gohome Thor left the _spaper man alone, and hewas no' a l,fIle depressed at the oeernmg neces­.1Iy 01 rna~"'9 !he Inp alone, no _ appeonngto want to ottempl ,I

Through ,he k.nd..... 01 Mr Co.. Irwon a goodhone was obla,ned, and obo!.oll,ye o'clock ayoung Mr. Morfin SOld he wovld go Secunng amule "whase nome was Maud.: but was oher.word ch,,"ened "Dynam.te" for reOlOnslhal WIllappear, he ond Ihe Kflbe fared lorth

Cache Creek canyon is a mONel 01 nolure'shand,work. The stream 1I0Wl 01 the bollom 01 alremendou. gorg", who... mounlo.n ..d" areIrom one 10 two IhoulOnd feel high - ....pmounlo,n rodge. 01 'Irot,fied .Iote, Iy,ng alan on·gle 01 forty live degree.. and where the surlocehas wfflC"n~ydecompo.ed, co....red WIth aheavy growth of chaparral, monzonlto, scrvbook. some P"'01, and On InfiMe YQrle!y Ollhorny.......

Two hours lro...1brought us foee IQ foee WJIhthe Woodlond tourosll. They hod go... U9 in twopartl.... one on e<ther side 01 the creek. [YoloCountyl $I.Irveyor AshIeYs party aNy hodreached .... slid•. Mr Ashley r.ported Ihot[Ihe Iondslidel hod formed a complete dam In tnecreek aboullooo leet from bank to bani.. 100fee' wode< on top end wrrh a bose al~, tooofeet 'I W01 oboulloo feet h<gh and Its ""me....bulk and weoghl kepI It from being pI.Ished dawnstream by the greal _'9ht 01 water ,mpounded, ... waler was wirh.n I.n feel of me top, n"ng 01me rate 01 ... ,nches on hour, and could M u·peeted 10 run oyer In twenty hours, wh,ld the po,.llb.lity wa. Ihal ,he barrier would glye way Inmuch Ie.. t,me.

100 CALIfORNIA GEOLOGY May 1990

CI..o, ocr01l Ill.. cr....k wenllh...Iide, ca'ty,ngw,'h " bru.h and trees and ...en a bould.., oftwenly feet Or mo,e in diomele, thaI wo' pu,hedup on Ih.. tlotlh bank of Cach.. Creek vnhl ,t W':ISIh,rty or fony feet high.. , thon lhe c..nler of thedam, which WO' illelf aboul 100 feel h,gh.

Securely ,mp,nged ogolnl! a perpendiculorblvff 01 ," narlh .nd, wh,le the .ovlh wa. re,n.fo" ..d by On ,mmen", we'ghl of earth and de.bri., a dam loy aero.. Ihe creek Ihot ,f The wale,could be kepI from Row'ng over it. m'ghlllondfa, agel.

Calm and .erene 01 a .Ieeplng ch,1d a lake ofwale' loy above ,I, wilh lull enovgh MOllOn 10sugge.I lif.., bo.o! g,.. ,ng no h,nl of Ihe cruel pawer" could dilplay .hould 'I be loosed from theleolh, Oret 1000 feel ave'oge w,dlh, 100 feetd..ep and .ome .,ghl m,(e. ,n lenglh, he,e woo abody of wale' lhat set ,n mOI,on wdd..nly wouldwip.. oH Ihe mop Ihe o"ho.d. and forml of ap,olpe,ou...alley below d.

Pholo 2 General topog,aphy 01 the Coche Creek reg,on View loward Ihe eo.l. Cache Creek (bol1omcenler of pholo) meanders eastward through Ihe narlhern Coosl Ranges from Clear Lake 10 CapayVolley. Gloncod Mounla,n and Bl..... R,dge [on Ihe lefl and "ghl hOrIzons, re'9"ct,vely) mark Ihe Iran$<­Ilon from the rugged lerro,n of Ihe Coast Ranges 10 the low rollong h,lI. and ItlYel.xpons.s of Ihe Cen­lral Volley 11,1$1 beyond Ih. h,1I1 ,n Ihe pholo The obrupl vert'col scarp of a d"',ncl Iondslode can be seenOn GIo..cock Mounla,n, Reocl,volion of Ih'l large slide would impound Cache C'INk otld 11"8OletlSlole Highway 16

Now Irovelotlg 01 n'ghl up a conyotl from which"",ope would be more or Ie.. d,Hicvll.tI doyl,ghl

, ,s no fun, and Ih. tlewlof'Oper mati was tlol 01oN loUrpmed Ihal h.. compotl'otl atld gu,de, aflerthe alum'tlg porty had diooppeo,ed ,n Ihe dark·nom, should OIltloutlce lhal he 0110 hod bo.o.'tle..'n Rum.ey. aock he w.nt for home, otld Ihen 'IwOI up 10 the ollte, fellow 10 go on alone Or re­Ivrn 10 Rumsey 10' Otlo"", maker of ralh prom.i...s. COlching up w,th th. [Woodland) parly Ihe,.wo. found omang Ihem a young man. ""ho hods!Drted for the slode bUlla,led 10 reach ", beforeth.o1e who d,d, wonled 10 go home Th.s was AI·berT A. Alletl of Woodlotld. He troded h.. todedmul.lo, "o,.nomile" ridden by the homewa,dbound Rums.y mati, and ogom we were OU!'NOrdbound Th.. was Ih. Ihird componion Ih. hprened"or had been blessed w,lh ,n one day and hevlle'ed a silen! supplicol,on thaI he m'ghl be astoyer He ""01. A. Allon ,tuck 10 lhe mvle untilIhol pugnoClovs quadruped could no longercarty h,m, and .ofely mode the ,ound lrop.

Trave~ng on 10 Beo' C'eek, a $!ream o,lo'genow as" Pulah C,.ek in summer, we craned 10the d,,,,de, look up a can of woler, bu,1t a 'OUlOngfir. by lhe I,ght of whoch we drIed weI slock,ng,and Ole s.ord,ne. and crockers, and lokong a lurnin Our nedl,e. we c~mbedOn dowtly bed, of.0'. wilh Ihe YOuhed. 1I0t bede<k.d sky for acoverl,d and llept vnhl 4 o'clock,. occos,otlollygell,ng vp 10 replen..h Ihe fir. and chose Ihe fe.·I,v. woodtick.

Ago.n desc.tld,ng to the creek bed, windingbod and fOrlh oeron ,I vnhl Knob's ranch wa,reached five m,leslrom the .lide, Ihe hour hodcome ""hen ,t seemed foolhordy 10 court dong.t10000ger, otld we cl.mbed 10 the north "demounlo'n.

Choporral eve""",h.,..; mounlo,n ..de olmo,l100 .Ieep for progr....;'un fiercely hal, nO water;deep ",",n'" thol could not be croll.d, compel­ling long detoun Once mare we slid da""n to IheIlreom and follo>Vfld " vntil w.. lhaughllhe Illd..bo.oltwo m,l..s o""Oy and Ih..n, c1,mb,ng up Ihemaunlo,n on Ihe >DuTh ..de agom look up the","uggl.. w"h chaparral

Thot loll two m,I .., cOnlumed jUIltwO houfland at elevetl o'c1ack we slood allhtl tldge of Ih.barrtltl mounta,n llde f,om which somtl n,ne 0'ten acres 01 d,rt hod .I,d ,nla Cache C'tlek, ,top·pong ," Aow a' camplelely o,lh.ough the tlorThhod optlntld and Iwollowed up lhe wOler Thedam wa. complete Not a d,op of l,quod oozedth'ovgh ,I

Here wa. a greol barren .poce an Ihe mOUn·tam I,de lrom wh,ch th. s.oil hod all.lopptld owoyThe expo,ed ,urfoc. was yellow cloy and 'ock, hwal olmo,l 01 smOOlh O' the back of on.'. hand,and 'n many ploc....p"ngs of ""O!er were pou'­,tlg f,om "

Th. real couse of Ihe .I,de was nol hard 10 lind.H.. ,e wal a mounlo,n "de s.o .!eep Ihot climbingwoo d,Hkult F,om a hoghe, ,ang" Ihe r".ervo,nof Winler ro,n. w..'. f..ed,ng .p"ngllhol hodcomplelely solu,ol..d lhe f.w feel of ea,lh Ihalco..ered The cloy and rock,. and then well,ng Thehorde, Ivrloce, Ih.. h,ll.,de ocl..d IUlt Ioke Ih ..""Oy. of a Ih'pya,d II,pp'ng ," bo.orden ,nto Ih.leD below No earlhqvak.. woo needed. Gro..,tyand Ih.lack of adhesion did Ihe ""ark.

ICounty) $v,,"eyo' Alhley ofld Olhers of goodludgement expecled Ihtl worsi 10 happen. The,..was a chonce Ihal a. the middl. of the dam wallow.., thon the end., Ihe wo!..r wovld by culI,ngIh'ovgh the,e /itst, RoYoo Ilowly and thaI th.. ...,11

body of eorth requ",ng sO much hme to bewashed ovt would hold bock the flood un,,1 if wal100 Imoll to do ... t..n"..e domog... Th,s is actuallywhol happ..ned, and 10 Ihot" due the fact thaithe beoul,ful Capay ..olley,••liN ,nhob'loble

hetybody hod been fully warned Allan thelowlands hod token to Ihe hilil. h we'. belle.1ho1many moY..d who need nollhon Ihol any should.uHe•. Not a Me wo.lo,t and Ihe d..llruc"on ofproperly was incon"derobfe compared "",thwhol m,ghl have been

Leo..,ng the .Iode alone o'clock and feelingconfidenl il wovld nol go out befo,.. onolher day,we eo.ily mode lh. tnp 10 Rumley by floghl fall,whe,e T.O, Mor"n ga..e ul au' fin. worm meal ,nforty hours, and pro..ided comfortable bed, onthe hogh g,ound where we slept ,n peoce.

Till: 1906 landslidc:'f100d c:velll ()("­curred alllllme "hen lhe region "a~

much Ic ..~ dcn~cJy populalcd Ihan II bno". A ~imilar landl>hdc flood C\·cnllIx1a) In lhe ..rca would be a lhrcallQlire and properly.

CACHE CREEK STUDY AREA

The Cache Cred.: slUdy area i~ in lht'norlhern CO:l~1 Ran£c~ ~eomorphic prov­mce orCahrornia. apprO'limmel)' 75rmlc, ntlrth or San Fraoci"Co and ~6

lillie, "esHlorthwe~1or SacramenlOIFigure- I: PhOIO 2). The ~lUdy area e~­

lend.. appro~imately 30 miles dO" nSlreamalon~ Cache Creel: rrom lhe Clear L:1I.eII11poundmg Dam lin lhe Cil)' or ClearLal.eJ 10 RumsC) (allhe head OrC:lp;l)Valley. Figurc 2). Access is by w;'y or

CALIFORNIA GEOLOGY May 1990 101

,Figu.e 2 Reg,onol geolog,( mop of Coche Creek.1udy OreO Geology Irom JennIng. and Strand (1960). LaWTon (1956), and Wag..... and Bortugno (1982);locolly mod,f,ed by Monson 119890)

Fault - .alid where occurot.lr located; da.hed whereopprox,molety Ioco!$d; doned where concealed

SYM80lS

Conloct Synclin. +oc>.0 ••

'"O~

"

Alluv'um lHoJoce"e)lond.J,de deposll1(Holoce"e)Modesto-Rly_rhonk formOllOns

(orkosic oU'm"m) rPl.','oce..e'Terrace depoSlI1 (PleIstocene'Red Sluff Formohon (g.ovel In ••dd"hSIlty or sandy mol",,) (p1.'lIonn")CliChe Formallon [Pebbly sandstone,conglomeral', ..h.lone and tuff)(Plio-PI,'llon"e)Clea. Lake volconoes (d-doe,t.;a-andesl'ft to bo.olhc rock, b-bosolt.•• rhyolite; Huff and olh,r pyrocJosrlerocltsllPlio-PI."locene,-Qvotemoryconde' cone D. volconoT.homo Fa,mOhon (Sand, "b, and~olconlclo'hcroch) {Pilocene)Copay Formor.on (Monne .ondltone)(focene)

UNIT DESCRIPTION

Pmz Mort,nez FormatIon (Manne q...ort.ZOIe IOndltonel (Poleocene)

K... Upper CreIOCeO...S (UndifferentIatedmOnne roc..)

Kia Forbe, Formohon (Monne .hole and.,Ilitone]

Kg G""ndo FormohOn (Monne 1000itoneond mud.tone)

Kf F...nh Formollon (Man..... sI.ole ondsandstone)

KI Sites Fo,-mor,on (Monne londilone)Ky Yolo FormO'llon (Manne shale and

sand.lone)K~ Venodo Formollon (Manne landllone

and conglomerate)

KI. KI,p lo.....r Cretoceo..., Greol Volley Se·quence !Mar;ne mud.tone. lond~tone,

ond conglomerate) tKllp - delrltolI.rpenllne)

KJ ..., KI'P lo....e, Cretoceou.-Upper J...<O"'CGreat Volley Sequence (Mannem...d~tone, "lIltone. IOnd~rone. andconglomerate) (KJ.p - delnrol'erpenhnel

Kif F<onclScan Complex ("·,andllone,Ihole, conglomerote; cll·chert;gs·greenslone; mg·metogroywackel

...m SerpentInIzed ultramafic rocklJgd Gabbro and diabo~e

Slale I-lighwa)'~ 16 and 20, allhough largepOr!lon, of Ihe ll.e:.1 h:tlf of the CacheCreel area do not have impro\ed road~

and fell. road." lead directly 10 Ihe creelit,elf The widlh of the 'lUdy area mnge,fr"m one 10 lhree mile:.. and relief in lhearc:t approache, 2,200 fcel.

The c1ll1lale in lhe :.tudy area i.. chamc­tented by hOi dry ..ummcn and modemle\0, mlers. Snow ocea~lonally co\'ers muchof the arca during inten"C \0, mler storlm,\o'herea.. Ihe :.ummerllrtle lemperature:. re·fleclthe proximity of the area to lhe hoICentral Valley. Temperalure e,~lreme~ inIhe 'IUd)' area arc greater Ih:lll al Clear

Luke bee'au:.c II lad" Ihe moderalingeffe~'l, of lhe tal.e. Mue'h of Ihe areaI' to,,~red b) Ihld bru,h con'I'linguf chaml..,;', rnanzanlla, and bucklhorn.The remall1der I' l!ra~:.land \\1Ih :.tlilleredoal Ir('e,

The I'lIh)elaltline, of equal r•.IInfalljmap sho.... , lhe Clche Creel ,Iud) are:1received an :llemge of 25 10 30 lnehe, ofrJlnfalJ pcr ycar bcl\\een 1906 and 1956tRanl/. 1971). Lal.e!"lrt, (In lhe \\e,1margin ofClcar Lal~. r~cell~d an avcr·u~~ of 30 inche:. pcr )eM From Jul) I.11.105 10 June 30. 1906, 37,J3 Inehe:. ofr.lln fell on talepor.: all c,llIllaled 96.2pcrccntllflhl\al110UIll fcil fr"IIIJIII) I \ll

April 30 (California DqKtrlmCIll of \VlllerI{c,ouree,. 1%1. Table.. 2 alld 3).

There arc <.t\cral ~maJl raneh('\ up­'lream from Ihc Clcar Lale ImpoundingDam. and num('wu, farm, and r.mche\arc dOl'olhlre:lIll in Capa~ Valle) h'\\, Ifan~, PCOIlI~ Ii\e along Cach~ Cr.:el he·lll'een Ihe ~l;1I11 and Ihe vallc)", MOI,l of Ihe1:1I1d In lhe 'Iud) arca i\ Slale or Fedemlproperty (U.S, Bureau l'f Land Managc·ll1~nl. 1972). Thc gr.l~ .. land, ;rrc used forcallie llra7l11g. At'ce,s 10 mut'h oflho.' pri·\atc land III Iho.' arca i\ Cllnlmll~d b)hUllllng cluh~ lLawton, 1(56), A largeTule o:Il herd r.JllgC' Ihrough Ihe \lUd):Ir~a, and decr arc plentiful.

"2 C....UfORNI .... GEOLOGY May \990

STUDY METHOD

Becau"C lhe lerr;Jin in the \lud~ area he~tremely rugged. aeri:lll,ho1()', \.Iere[bell 10 condu{·t a land~Jide mvel1toryLand~lide~ :lI1d dcbn~ f1o\.l~ typic<llly en."ale dlslinclive l<lndform~. "uch <l" ~carp~

111 the ~ource :Ire:!" and hcnche~ and elon­gatcd bulge\ at the toe or do\.l nhill end(PhOIO 2). Selected :leri:ll photo" \.Iere ex­:u11Ined for evidenee of land..lide~ u.. ing asiereoscope and identified l.. nd~llde) \\crcplolled on a base map hcale I :24.000l.Exi\lll1g geologic nlllpplllg wa!> al"o l'om­piled on the base map. Field obM.'rvationof land~1 ide.. wa... limited to aC('cs.. lble:Jrea~ along Slate lhghway~ 16 and 20.along Cache Credo bet\\een 1\::lehtreeCros~ing :md lhe North ForI. nf C;JcheCreek. and frolll ..e\'Crul visla points alongC:lehe Creel. canyon. Field ,tudles weremade m 1:l1e 1988 alld carl) 1989.

GEOLOGIC SETTING

Rock Units

GeologiC unit .. \.I Ithm the LO\.ler Lake11.5 nunute) quadrangle (at the \.Ie~t endof the :>tud) area) include the Cache For­mation IPho-Plei'iLOeene: R)1llcr. 19711:19111). -.orne uhmmaflC" and ~ilica car­bonate rod.. Ihal are part of the CoastRangeophiolile' (Brice. 1953). and Cre­taceous sedimenlary Uilib n{':lr LowerLake and MlddlelOwn (Swc and I)lel.ln­son. 19701. Adjacent parhoflhe Wi!""nValley ;Jnd Glav.cod. Mountam (1.5 IIl1n­utel quadrangles to the e:l<,[ IIH:lude theGreat Valle) Sequence of Upper Jura~-

.. ice) and Cretaccou .. ail-c. and other unlh'uch as the Cache I'orrnalloll (Lawton.1956). Detailed m:,pplnil- along C:ll'hcCreek in the vicinlt) of Wilson Valle)"a~ conducted dunng an investigation ofpro(JO'ed dam~lle' 'ScotL 1970),

The Great V:lllc) Sequence compri'es,,\'Cral di,tml·t geol0il-Il' formations in theca..tern and central por\lon~of lhe "lUdyarea (Figure 2) Thc\c formations con.."tof interbedded ..hale. nlUd\lOne. ,and­"lune and conglomerate strata that dip)tcepl) ea<,[\.I:mL and arc highly fracturedand JOll1ted. Area .. around CleM Lake thatarc underlam by unih correlated wllh\Ome oflhe formation, (the Vcnado andBrophy Canyon Formation,. the BlueRidgc Member of the Crack Canyon For­I1I:U ion. and the .. Unnamed Mud"lone"Formation: UnIt' Ilk. lila. Ib and 1:1. re­,pectl\el). of S.... e and I)ickm.."n. 1970)wcre claS'iifled:l' "Most Su'Ceptlblc" W

land,lidcs and debris flo...... lMlln..on.1989a). The Cache Formation. \.Ihich un­ckrlie.. the \.Iestern ponion of the CacheCreel. qud) :lrell. is an unce11lenled lInd

Pho'o 3. Poorly sorted 10nd ond gro~el 01 ,heP1io-Pleilloc;ene C<Xhe Creek Formollon 01 ,rl'ype lo(oilly olong Nil"" Long Volley Rood. LakeCounly. Vie"" lIra rhe ""e,' PerlOn IS aboutSleet. 3 ,nchel loll. The type kKol,ty of ° rocklormot,on is the oreo where Ihe 10rmo1<on ""0'f,", re<:ognized ond deKribed Note ho"" rheuncemllnted ond uncon.olldoted led'menlS ho~e

reod.ly eroded Irom rhe runoff 01 ""nte< rOlno.

rel:lti,"ely uncon<.ohdated a..semblage 01poorly ,orted cobble g.raveI,. 'and ,Ind \lIt'Photo J). Areas around Clear L:ll.e thatarc underlanl by th" unit life also de\lg­natcd as "1I-\0\t SU"CCPlihlc" to land~lidc'

and debrrs flows (Man"un. 1989a).

lond$lides

A land.. lid... I" ddlned a, a tII:I" ofrocL wil. and debris thaI has becn dl~­

pl:K'"ed do\.l n"lope by ..Iidlng. llo\.ling. or!'aillng Lllnd.. lide, Include eohe'lve blocl.gild..., ,lI1d dl,rupted ,lump, that ha\Cformcd b) tran!>latlon' or rolallOn· of the,lope tn:uerial, along one or more plan;Jror curl'ipl:lnar ,hp ,urfaces. The Ca,'heCrecl. land.. llde halard Illap ,Ill"", me­dium and large land.. lidC\ lhat :Ire VISibleon the blacl. and "hitc aerial pho(()', u'ol.'dfor tht" "lUdy In addltnJt1 lIIthc\{' land­\!ide... therc .Ire mnumcrable unmapped"malll;lnd.. lide,. dcbrt .. avalanche ,car...and mel. F;Jl!s alollil- Cache Crccl. and 11\

trlbut;Jrre~. Due W ,lope 1I1'tablltl) fac­to('\. both the largc :Ind "mall ..lope fail­ure, .... 111 {'onltnue III (lCcur (l'holO "I.

Ca(he Creel. IS Jn anlecedent· ,tream.It maUllaltl' It .. original ea'terl) cour",through mountatn, th:1I are belllg upliftedbe{'au\C the v:lriou.. geolngll' unlh tnl\­er\Cd by Cal'hc Cred. erode rclati\'c1yc:I'lly lI'hotO\ 2-4} M:1I1} of the "lopefailures are trig!:!ered by unden:ul11l1g Jndero~ion of lhe hill,ide ,lope" b} CucheCreek and Ih tributaries.

When ,hale and ~and~lOne ullllS an~

steepl) dlpplOil-. thc Ie.... rC"i\tant ~hale

bcd, arc eroded dov.n tn... dip and alongthe upper ..urf:lee of lhe n\(lre-resiq:ll1t";Jnd!>lOl1e beds. The ~llnd..tonc bed~ acla.. pa\ernenh Oil the dip .. Iopc\ lth<.l'ol.',lope, lhat are parallcilO the direction ofbeddmg till) Thc luud..lone ...hale. :lnd'<lnd!>tol1e layer.. that arc 'tmtlil-rJphicall~

above the "paIement" bed~ are eroded b)unden:ulling on the llnlldlp· ~lopC\ (Fig­ure 4). and. therefore. arc highly suscep­tible 10 Illnd~liding and debris f10W'iCKadhrueh and Weiler. 1963). Well-dC\'cl­oped jointll1g or fmcturing weakens the~tr.. t:l and inlensiflc, ,"~eeplibllll)' 10

landsliding. JOlllt~ 10 the rocl." provide apalh for il-ruundwater infiltration and mI­gration. wll1ch reduces coOe'lon of thesedllllenh Researcher' h:l\'e found thlll a~

man) a, 90 pen:ent of act IV{' slope fail­ure, de\elop on alUldlp ,lopes in tilted.rCil-ularly Jointed ~dllnenlllr)' rock,{Koger,. 1986. p. 25}.

Other ,lope failure) are trlgil-ered byIIIcreascd pore-water prcs~ure (pressureexerted by groundwater \I ithm Ihe ,"oidsbetween mineral grams in ..oiL alluvium.:lIlll bedrod.) due 10 lhe infiltration ofrall1water. The re~ulllng deereaM.' of ..hear'trength (internal resIstance 10 dcfornw­110n by \he:lrll1g) can cau!>C "lope failure.Thc le,"cl of the water table (depth 10

groundwater beneath thc land ..urface)\'arie, \\ Ith the amount of mtnfa!1 for thearea. During the \.lInter. the water lableand pore-waler prc....ure ri-e becau,e ofItlereascd rainfall. and during the ,umlllerand fall month .. the \.later t;Jble and pore­\.later pres~ure drop becau.'oC ra1l1fall i..negligible. If r:llnfalll" hIgher than a\er­age durmg the .... intersca~on.the watertable will be h,ghcr lhan :t\'ct"Jj!c on a hill­slope alld ground\\<ltcr prc....urC"l ma) be­("ome d:tngerou~ly hiil-h Under lhe..econdUltm". hilbide mO\clllent could be:lcll\Jtcd hy an e:lrthqual.c. or {)\'CfS:llUra·tlon of \CuI b~ ad<.htlonal minfal!. or \j­

br.Ltlon" from c~pIO\ion.. for road{·on'lruction.

Numerou\ "ludies ha\e ..hown a corre­lation bet .... een large earthquake, and in­cident' of land~lide~. Land.. lidc.. thatwere lriil-gered b) ..0 hi<.tori<"al e;Jrlh­qU:lke, ha\'e been documented (Keefer.Jl)l(4). The magnllude 7.1 Loma Prietllcarthqu:ll.e of (ktober 17. 1989 activatedmany land~lide, 111 Santa Crul County(Manson and olhers. 1989~ Spittler andolhe,...,. 19891. A landslide ncar LalIunda. 111 S;Jn Mateo County. California.which occurred 33 lillie" away from theepicenter. was probabl) triggered by lhe~lorgan Hill (M 6.1) earthquake of 1984

CALIfORNIA GEOLOGY Moy t990 103

Conglomerate bed. 0 0 0 00. 00 (> 0" 0 00

Foult _

Unit contoc!

landslIde' Arrows "'ow directIon of~downolope movement ~

KJ",m

The 1906 Cache Creellamhlidc mowdWIth such velocity thai a boulder 20 fCCI111 di"meter wa\ c..rried :l(;ro~~ the can)·tm:,nd lifled more Ihan 30 fCCI abllI!C thcmain tna\~ of the dam. Thc Ircmor fcll IIIC:lP;IY V:Illey on Ihc 11Ighl of May I eouldh:lve been cau'-Cd hy thl' 1l11p;!CI of Ihelaml\1idc (Scot I. 1970l, Allhough thl\ 1\\ery pt)!,~lble. an altern..u\'e h)'pt)(he~l\ isth<lt .. \lIIall eanhquale did Ol'Cur locallyand triggered Ihe lan(hlidc. No localcarth4uale of magnllud;: 4 or largcr 1\h~t;:d for Ihat dale nllpptllad.. and olhcr\,1(78). Onc earllKjuale wa~ reported at9:.10 p.m. on thai dale near GuerneVille.Sonoma Coullly. appro'wn:llcly .Ut mlle\we\t of Cap;ly V.. llcy. 111\ 11\led ;I~ MMItllcn~l1y VI (fell hy all pcr-.on\).

Belwccn 1969 ,IIUJ 1984 Illore tlwn 36..mall earlh4uakes (magnitude 1.0 til 2.1J)necurred m lhe region betwecn Ihe I'xx,Cll'he Creelland~lide ltx:alily .. nd LalcBcrr)'C\\a, :lpprOltlt11,ucly I') mllc\ Wille\<luth. One C;Lrlh'lual.c epiel'ntcr w.. \ only:! l1tilcs WC\t \)f the I:md.,lide (U,S. Gen­lug leal Survey, !lJlS5), The ~allJe <llllnuntlit micro~ci\l1tieityItwy have occurred litthe rcglon til 1906, but bccauM: therewcrc nn in\lrUmcltl\ ,'arablc of re"ordlng,Iny \tt1:111 earth4u..lc\ ncar Cache Creel;11111..1'1ItIC.;1 hypo'hclicai "triggerin.!:!"earthquake would nol h..vc beenreeordcd

(Wieoorcl and Kcefcr. 19H7). The Jl)(}6

C<I<.:hc Crcell:H1d~lldc m:lY h;l\'e been 1111­

tiated hy the nmgnnude H,:!5 S,ml·r.ln­('l~('lle;lrth4Ualeof Apnl Ifl. 1906,although lhe epicenter w.. \ about IB Inile\\oulh Oflhc c.lchc Crel'l arca (Real andmhcr\. 1(78), The 1906 San t·r.H1C1"C1lcanh4uale oc(-urrcd <It the end of a .... In­ter Ih:1I had higher Ihan norm;11 rJtnfal1.The ~h:lking Inlen\lly fur Ihc region ~ur­

rounding Ihe C<lche Crecl. lamhlide 1\e\lllU;lled III h<l\'C been V_VI on thc~ltxl1l'ied ~krcalli (MM) !>Calc durmg theIt)(X, c<lrlh4uake ISl'OIl. 1970), Shall".....hlghl) dl\rupted lanlhlidc~ from steep\h}J)C\, \Ul'h a~ ocl'urrcd at Clchc CreelIII 19Otl. arc common at MM VIIKcefcr.11)114. p, 420), Ahhough the 1906 CocheCreclland~llde wa~ nOI in~lanlaneou~jy

trig1.!cred by Ihe earllKju"ke, the a~soci­

alcd ground milt ion may h,lVC opened in­clplenl f.. ilurc Ill<lnc~ in Ihe ~Iide nm.\~

;llong which groundw<ller pcrcolatiolll'au~ed hydrc)!,talil' pore pre~~lIre to in­l'rea'-C. rc\ultmg in ~1"Jl'C failure 12 d<lY~

later (Scolt, I1J70. p. (5),

.. figure 3 Geolog,c mop of '''e 1906 Cache C,,!e~

landslide locolity (from Manson, 1989b, mad,f,edfrom la....'an, 19S6),

1\\

Klvj"\-

\

01.

Kccgc

29-

UMIl tf"ckness in the ,tudy 0.80"greater ,hon 4,200 f....1LHTLE VALLEY FORMATION, LEES­VIllE MEM8ER (low•• Crelaceous):PredomInantly huH, light-g.oy oryellow·brown sand.tone, w,lh ,nle'­bedded .hale and silly shale ondoccaSIonal conglomerate. Un" ,s 600to 1,800 f.elll·"d, and ,est. can­la.mobl.,. upon the "Gnzzly Creekmember" of the "C.ock CanyonFarmol,on H

CRACK (ANYON FORMATION,GRIZZLY CREEK MEMBER (lower((fIlaceousl Predom'nonliy .hale, sihylhole, ol\d mudstone, ","th oc:co..onollondllone ond .eve.ol conglomerotelen.el; conla,nllh,ck Ie"... of detrrtQI"'P'"'tn,telocolly. Un,llh,dne.. OJ

3,200 '0 4,600 feelCRACK CANYON FORMATION,BLUE R'DGE MEMBER Ilow.. Crekl·ceou~): Conglomerole ond sond~lone

.... ,th some ,nle,bedded mud~tGIMI.

Conformably oyetl..~ Sulphur CrH~formatIOn (lOWIOn, 1956; S....e ondDIC~,nson,1970j Un,t th'c~nen ,nthe ~Iudy areo,~ opprox,motely2,100 fHtUNNAMED MUDSTONE FORMA_TION lUpper Juro~~c·lo....er Creto­ceo~l: Domlnanlly mudltone ....'1..

m,nor sond,tone ond conglomerate,''',n-bedded cheri ond ptl.o.... lo"a~pr.,ent neGr bo~e of un,l. S"ole ,smedium'o don bro.... n or gray; sand·"one ,s green"h gray 0' brown. In·clude, Knoxy,lIe Forma"on (Broce,1953), Sulphur Cree~ Formalton (lo.... ·,on, 1956, S....e ond D,ck.nsan, 1970)

Kccbr

KJo

Kccgc

'''''

UNIT DESCRIPTION

AllUVIUM IHoloceneJ: Depo.." ofgroYe~ sand, silt ond cloy along Iheoc""'e ~Ireom c"onnels; ,nclude, smollpolch... of older bedrock locolly.LANDSLIDE DEPOSITS (Holoceneond lale Pleistocene): Include' land·,I,de, mapped by pre",ous ....orker>;many ol"er smoiliondslide, ex,~1 bu'Ore nO! s..o.... n; orrow~ ,ndicate gen­eral direchon of moyemenl. landllid.,Ihot curren,ly oppear'o b. ,table canreod,ly become remobilized by,ncrealed predpito!ion.TERRACE DEPOSITS (Holocene andPlelSlocenej: Uncon~o!ido'ed to semi­consolidaled ollu"ium depos,ledmo,nly by slreom" .... ,th m,nor lokebeddepos,,, of "Ils'one and mudstone; el.eyaled obo"e pre~ent ~tream cllonnel~

and la~e bo"ns,LITTLE VAllEY FORMATION, ROUNDMOUNTAIN MEMBER (Lo....er Creta·ceou~l Predom,nontly lig"l.groy 10

bro....n sllole and ~Ity ,hole, ...." .. m'­nor mud,lone, ,nlerbedded sonc!,'oneand some limestone, conla,n~ detnlolserpenhn"elocolly. Conformably oy­etlo,n by ,"e Baldy Maunlo,n memberof ,"e Doy;s Canyon Formollon, ondconformably Oyerl,es the leesy,llemember of tile l,lIle Volley Formo',on

•L N

Q"

SYMBOL

001

"" CALIFORNIA GEOLOGY May 199(1

Photo. Exposu,. of n.orty ....rTlColly d'pplng11<'(110 of the Fisk. Cr.ek Fo,mo~OfI roc:u. Greo!Volley Sequence, olong SlOt. Hoghway 16 KlUthof C>lo1.Koc:k MounlO.... View,s 10 th. IOVIh. Th.debns lhol foils off th. outcrops, slKII gS fromlIeo'7 ro,ns, _es downslope wllere ,t eyenlu·glly reoc:lles Ille Coc:he Creek chonnel. Tilegmgunt gf debns Ifgnsporled by tile llreom de·pen~h on Ihe omounl ond ....Ioc:,ry of tile wgler·flow. With 'ncreased llreom flow c1gy ond sill ore'rgnlporled firsl, followed by ""nd, pebbles. cgb·bles tllen boulders. F,ner sediments gre cOrrled inwsperll,on gnd gel gl on obros,ve slurry glongtile length of the chgnnel.lorger c1gstl arebounced and roll"d along Ihe channel bed bywOI.r oclion. When the Ilr"om has remoyed gilof Ih, led,menllrom lhe bed lood, eros,ve forces'hen begin 10 scour tile chonnel, downcun'ng ,ntothe bedrock. Teclonic upl,ft of Ihe Coall Rongesproduced dromot,c fold'ng and foulhng and~oused tile entrenchmenl 01 Coclle Creek.

SUMMARY

I)MG land'lidc pro~mm 'laff madc thefoUo-.- mg tOIlc1U'lOn, from d:l1:1 galhereddurmg the Cache Cree!; land~hde

m\'c:.llgatlon:

I. Nurnerou' land~hde~. bolh aetivc anddormant. arc pre\.C1lI alon~ Cache Crt.ocl.Nexablc Jarl(hlidc~ an: located at GI:L'>~·

coe!; Mountam. Round Mountain. andalong the South Fori. (maUl braoch) ofCache Creek upstream from Il~ eonnu·elll.'e \\ Ilh the North Fori. The 1906Cache Creel. land~hdc. located alongCache Creel. acfU'>~ from Round /I.'loun·tam. I~ ea.'ily idcnllfied on air phot".. andIn the field du.: to the large htllslde '>Carand II:) rclall\'CI) fre;,h appcaraocc_

2. Landslide :K'uvlly m Ihe arc" .... 111occur in the future. Some of the Illrj:.erexisting Illndslidc~ could bloc!; lhe l·reel.If the) \lere rellc\l\'ated A lanthhdcl'omple:\ locllted on lhe 'Outh face ofGlasscock Muulllain althe ea,tern endof the stud) area coold blocl. both StaleIligh\l";ly 16 and Cache Creel. If II "reactl\Olh:d.

J. A fe.... eXl~lIng Illtllhl,oc, along theSouth ForI. of Cache Creel. .... Ilhm onemile of lhe Clear Lal.e Impoundm!:! Damarc located in areas \lhere the creel. clluldbe bloeLed if one or more of lhem be­come reactl\... led and dammed the creel.The ImpoulKk--d ...."atcr would flood ClcllrLale bobln.

4. The "IOO} area l~ a tel'loolCall} acll\'C

regime \lherc upllftl~occurnng. Thl'pr-occss leads 10 the O\'C .....teepcnmj? of~lopc~ along Cache CflOCl.. Ihu~ mcrea~mg

their in~tahllity. The Eocene, P"dlcoccne.and Cretaceous rocL: unll~ In the llrelleonslst of :.hale, nlUdS/one. -.an(htone,and conglomerdtc ~Irdla Ihal are ~leepl)'

dipping and highl} fr,ll"tured. The Pho­Pleistocene Cache Formallon "uneon~ll­

wled and unl-elllCnted Althoogh ~alllplc,

ofthcsc rock units \lere nOlte'ted III alaborJtOf}. Ihey can be expeeled 10 ha\'erelatively low shear 'trength. In add ilionthe\C rod unit, arc rc!atl\ely e;I~Ily

eroded.

5. Thc geoll'lorpholugy uf lhe :lrCll al-ocontributc~ to landslide aCtlvil)'. The ell.'I­ward trend and lIleandcrinj:.Il:111ern ofCache Creek formcd prior 10 the uphft 01

the pre~cnt-day fllounlllin~. Due to the rel­lIli\'C e:L~e of CHlloion of the ,urmundingrocb. Cache Creek maintained it~

cour~e. O\'er time the cree!; cut deep inll'lhe ri~ing terrain. 'lilday Cache Creel. isconfined by ~lecp banb. Undefl1l1nillg ofthe ~teep ri\'emanh by latcml ero~ilJll IIIthe creel. l:hanncllm' lIt:ldc thcm UII­

~tahJc and sU'>Ccpl Ible to f;Iilurc.

A LESSON lEARNED

The folio-.- lilt; llrtlcJe I' lal.en fmlll the5mnlllll'/lW U'lilJl! of Ma) 10, 1906.

CACHE CREEK flOOD HAS A LESSON

People of Copoy Volley Find Out Thot PromplAdlon Is Needed Under Such Cw<;umlfOnces.

GUINDA. Mer 9119061_ The IMson Ieo.nedby lbe people of Copoy Volley f.om re<:enl expe­nenc. WIth lbe Ior>dlJode ... !he Coc:he Cr_~ <;on,)'On wbi<:h Ihreoler>ed greol domoge to propertyon !he volley IS thai such obstruct-.s shovld bedeered owoy ommeOiotely II IS bel-.d thai lbehmely use of 0 wfficenl quontlry of dynorrutewould ho.... OOvooIed aI !he donger hom .....

A

B

o

FIg"re. Four stages SIloWlng /he developmenlof volleys w,th olternottng >hole (shl ond ""nd·slOn" {.s) Ilroto (offe. Rodbruch ond We'ler.1963. Figure 7).

A. Gully formed ,n lOInTed _lined slloles (top).II Roy,ne formed by enlarge....nl of the gully,dlHllo e,osion down t+oe dip of t.... mor" ••sillonl""ndslone .lr01O by undercun,ng the sllgles.C. Conl,n"ed erOSl<)n down dip resull'l ,n formo·loon of 0 volley w,th sand~lone gnd shale bedse"posed on both s,d"s.D. A Jorge' volley w,th ""ndslone ond shole e,,·poled on bolh s,dei-. Th" ""ndstone slroto lho.d,p ,n the opposile d"ecrion 10 the votley lid. foilwhen Ihe 5110le 'nte,beds wosll gwoy. Th" sand_stone bed. the d,p in 'he lame direction os thevolley s,de erode more slowly than the shol",form,ng ridges thgt <><;1 as bunreslel for Ihe 5hglebeds.

IhreOlened overflow and would hove preventedony Icore 10 Ille peopl" living ,n Copoy Volley.Ngw tho. ";1011 Oyer il seem. eo.y "nough tg e"·plo'n Ihot lhe danger wos not s"rious. bUI whileIhe wgters were gathering in Ihe conyon beh'ndIhe b'g emOOnkmenl coused by the londslide the.es,dents of the volley below were nol ,n 0 pos..t,on to toke a pMosophicol yiew of the monerThot W05 why some of Illem gOI Kored ond look10 the lIi"s w,th lheir h<wsellold goods and morevoIuoble belong'ng5.

ACKNOWLEDGMENTS

I \I I,h to thanl.. Ralph ScOIl. of the C.al­Ifornla Department of Water Resource,.Red lUuff ofnee, for pro\'idin~ data COll­cernlng the 1906 C:tChe Creel.. land~hdcdOO flood. Th(" 51',fflll/('/I1O Union and\\//11"1";1 f;"lpr'''U !!enerou"l} grantt"d per·ml\~l(Jn to CALlRJRNIA GEOLOGY 10repflnlthelr articles.

,

CAliFOiNIA GEOlOGY 105

ontetedent .Ireom: 0 slreom lhot moonlolnlllsoriginol tourse during 10<:01 uphll Ordelormallon

gntidip slope: a hill shope d,pplng.n Ihe oppo·lite d"edlon 10 the d.p 01 loxolstrolo Or loll 01the lond .urloce.

8r1ce, JC~ 1953, Geology 01 lowe' loke 115')quod,ongle, Col,fo,noo Col,lo,nlO O,VIt,on 01M'neo 8ullehn 166. 72 p.. 3 plates, tcole162.500.

CoMornoo Oeportmenl of Conservohon. O,V'''O''of MJ"et ond Geology, 1988. lo"cftllde Hor­o,d Ident,licohon f,og,om, An"uol Repon.8,

Col,lo,"1O Deportmenl 01 Waler Resources. 1961.C1eor loke·Coche C,uk botr" l"vetl>9OI>on8ullelln 90. 265 p" 3 0PgendlCet, 55 lobles.19 p1oles.

JennIngs, C W, o"d Stro"d, RG~ 1960. SontoROIO Shut Colllor",o DiviSIon of MIne. andGeology, GeologIC Allot of Cohlo,",o, Kole1250,000

Keefer, 0 K.• 1984,lo"dlhdel couted by eorth­quakes GeologICal Soc,ely 01 Ameflco 8ulle·11n, v. 95, no. 4, p. 406·A21

lowso", A.c., ond othef'1. 1908, The Col,lo,,,ioeorthquoke 01 AprollB, 1906; Repon of IheStole Eorthquoke Inve.tlgot,o" Commluion,Co,negle Inllllule of Wosh'''gton Pubhcotlon84. v I, ports I and II, 4S2 p., 01101.

Lowlon, JE., 1956, Geology 01 Ihe north hall 01the Mo'gon Volley [15') quod,ongle, and Iheloulh holl of the Wilbu, Springl [15'1 quod­,ongle Unpublished Ph,D. diSienolion.Sloniord Unlve,Slty, 223 p., I plole. scole148,000,

Monson, M.W., 19890, londshde hozo,d. ," thee<ltle'n Cleo' Loke oreo, loke County, Col<­for",o Cohforn,o Deporlment 01 Conse",o­t,on. Div,,,on of M,nes ond Geology Open.file Report 89.27 (Londslide Hozord MopNo. 16), 4 plates, Kol" 1-24,000

Monson, M.W., 1989b, londillde hazord. alongCoche Creek between Cleo' Loke ond CopoyVolley, loke, Colvso. on<! Yolo counhes. Col,.lorn,o Col,lo'nia Depo,tment of Conlervo·!>on, Div,..on of MInes and Geology Open.File Report 89·30 lLondil,de Hozo,d MopNo. 19), 124,000.

Monson, M.W., Kefe', OK" ond McK.""d. M.A~comp,lef'1. 1989, Prehmlnory ,econno,nonc:elocollon mop 01 londshdes and othe' geo·logIC leotu,e. ,eloled to eorthquoke .hokIng,n the Sonto Cruz Mounlolns, Col,lorn,o, 'e·lulling I'om Ihe Lama Prieto eorthquoke 01

Glossary

ophiolite, 0 g'O\,Ip of mol«; ond ult,omal..::'9neou. 'cxks tho! formed dunng the eo'fyphole 01 0 de.-elopong OXe<ln boSln

uh,omolit 'otk: '9neou. 'cxk thot II comprIsedmaonfy of mo',c (do", tolored) mlnerols.

REFERENCES

CXtobe, 17, 1989 Col,lorn.o Depo"men' 01Conlervol.on. Div'lion of M,nel ond GeologyOpen·F,le Report 89.29 lin preIS)

Ilodb'uch. DH., and We.ler, LM., 1963, Prehml·nory ,eport on londlhdes In a port of IheO,indo Fo,mohon. Conlro COtlO Counly,Col,lo,nlo U.S. Geolog.col Survey Open.FlleReport, 49 p

Ronlz, S E., 1971, Mean onnuol preclp,tOllon ondpreClpitohon depth-du,otlon.f'equency dolofor the Son F,onClKo 80y reg,on, (olilo,nlOU.S Geolog,col Survey. Son f,onClKo 80yRegion Env"onment ond Resources Plonn.ngStudy 801M: 0010 Conl"buhon 32, 5 p. 1plote, Kole 1250,000

Reo1, C.R .• Toppozodo. TR.• ond Po,ke, 0 l. 1978,Eonllquoke epocenler mop 01 Co"'o,nlo­1900 th'ough 1974 COMO'fllO Div'llon 01Mlnel ond Geology Mop Sheet 39, scale1;1,000,000

Roge.., JD.. 1986, londll,de p,ocesses 01 IheEost 80y HoUI FIeld T"p Gu,debook 10< tile29th Annual Meellng 01 tl.e AISOC'OhOfl 01Eng,neerong GeologISts, Octobe, 5·10, 1986Son f,ont<lto Auoc,ot,on 01 Eng,nee"ngGeolog..!s, 90 p

Ryme', MJ.. 1978, St'oh9'ophy 01 Ihe Coche for­matIon !plooxene ond PlelSloceflef ,n Cleo'Loke be"n, Lake Coun!)', Cololo,",o U5GeologICal Survey Open·file Repo,,78·924,109 p., I plole, Icole 1 24,000_

Ryme" M.J., 1981, S!rolo9roph,c ,ev,s,on 01 theCoche Fo,mohon (Phocene ond Ple'ltocenel.loke County, Col.lo,n,o US GeologicolSurvey 8ulleton 1502·C, 35 p

ScK,omento UnIon. 1906, (oche C,eek flood halo lesson _ people 01 Copoy Volley find outIhot prompt odion ,t needed ~nde' luch ci,.cumtton<es Moy 10, 1906, p. 6

$coh, RG. 1970, Londlhdes In CCKhe Canyondownllreom Irom the W,lson Volley Dom,,'es­Col.forn,o Deportmenl 01 WOler Re~ourcel.

Norlhern DIStrict, unpublIShed Memo,ondumReporl, 28 p, 4 plotes,

$con, RG., 1971, 'I.e '06 Iandshd" on CocheC'eek (olltlroctl· AssoclOhon of Eng'nee"ngGeologISts 14th Annuol Meellng, P'og,omond Abllroctl, p. 35

translational slide, downilopll dllploument 01.Iope molenol along a planar .I,p lurlo<;e

rototionol slide: downllope dloploumenl ofllope molenal along 0 tu",.plonor tl,p",riCKe

Splllle'. T.E., ond Horp, EL~ compile.., 1989, Pre·I,mlnory mop 01 Iondsr.de leotu,es and co·le,~mlC fissu'el t,igge'ed by the Lomo PrIetoeo,'hquoke 01 Oclobe, 17, 1989 Col,lorn,oDeportmenl 01 (onse",ollon, O,v",<on 01Mine. ond Geology Open·flle Report 89·28,Kole 14800 [in pressl.

Swe, W" ond Dickinlon. WR_. 1970. Sed,mento­toon ond Ih'uston9 01 lole Me.ozo,c 'oxkl.nthe Coost Rongel neo, Cleo' loke, Colilorn,oGeolog,coI50c,ety of Arnerico 8ullel.n 81,no. I, p. 165·188, 8 figu'es.

Toppozodo, TR., Parke, D,L., o"d HIggIns, CT.,1978, St,,~mlC<ty of Colllo'nio 1900_1931. (01­Ilo,n,o O,v't.on of M,nel ond Geology Spe·clol Report 135. 39 p

US 8u,eou of Lond Monogemenl, 1972(19751.Surloce monogement .'o'us, Heoldsbu'gquod,ongle, stole 1100,000.

US Geolog,col SUNey, 1985, CAlNET eorth.qvoke doto (preltminoryl_

W.A.C Co,po,ot,on. 1984. block ond wh,te 0"photos. se"es WA(-84C, photos 4·80­4·83,6·83 - 6-86, 6·251- 6-254, 9·68- 9·72, 9·196 - 9-201, 10·52 - 10·5A, 11·81 - 11-85, Kale 131,680

Wogne,. DL. ond 80rtugno. E.J.. 1982. Sontofloso qvo,ongle D,v,sion 01 MIne. ond Geol­ogy, ReglOnol GeologIC Mop Senel 2A, scale1250,000,

Wieczorek, GF., ond Keele" 0 K., 1987, forth­quoke·troggered londt!ide at La Hondo, Col,.lo,n,o ,n HOOle, S.N, edlto" The MOfgon H,II.Col,fo,n,o. eorthquoke 01 Ap,il 24, 1984 USGeologlCol S~",ey 8~lIehn 1639. p. 73.79

Winters Express, 19060, Took to the hlU~ - bIgland srrde ,n Cache C'eek domt Ihe wole'and tco,ellhe people Moy 4, 1906. p. 3

Winters Exp,ell. 1906b. Whol hoppened toCoche (reek - The greol dom goe~ out eOlyond nobody" h~rt - ,moll property lOll atIlumsey and loll 01 exc,tement oil olong theueek,Moy 11, 1906, p 1.

Wood/ond Do,1y Oemcx'ot. 1906. (oche C'eekloll. rop,dly _ cou.e unknown Woodland,CA Woodland Dooly Democ,o" Moy 3, 1906,pl_ ~

'06 CALIFORNtA GEOLOGY Moylt90

Geology of an Area in Altamont Hills,Diablo Range

Alameda and San Joaquin Counties

By

ALBERT L lAMARRE, DAVID W CARPENTER. MICHAEL J. lAFfEY, AND NEil B. CROWlawrence livermore Notionolloborotory

livermore, California

••\.... Site 300

'\

filled \lollh laIC Terliar} 10 Holocene sedl'menls. malOl} dcri\'cd from lhe surround­109 mounlalOS.

The pre.-.eol ph}'l>olograph) and geologyof lhe Coo~t Rangel> arc Ihe result of de·formation and depol>itiona[ processe,:llong the teclome boundary belwcen lheNorlh American plate and Ihe P'dCllicp[;l1e (.. nd ils predecessors. Ihe Juan DcFuca. lhe Farallon. and Ihe Kula plales)(I)..Jgc. 1982).

Mil..10 15 20

I I Ii,I

Pacilic Ocean

Figure 1. Regoonol \.en,ng allowrence l;"ermo,. Not,onoIlaborCl!Ol'y and S'le 300. AlIomorll H~1s,

o.oblo Range, Alomedo and Son Jooq",n COUl'ltlel, Caillornoo

graphi<' prO\ lnee. bel\locen Ll\'crmore­Amador and S.. n Joaqum \'alleys (FigufC2). TIx: Cool>t Range phy"ographle prm·inee consists of a sy... lcm of norlh-north­wcstlrcndmg. faull·bounded anticlinalmounlam range'. and "foclillal \'alle}'s.Bedrock coos"IS of 19oeol.h. metamor­phIC. and sedllllentary roc!"s Ihat rangeIII age from Jura~l>lc to Plc"locene. Themouotalll mngel> arc cOIllJXll>Cd of Jurassicto Terlillry age rock" and locally may ex­cecd e1evallon, of 4.000 fecI. Valleys llre

The 'Ill,' lopogrdph} includes '\Oulhea~­

lerl}'lrendlng ndges and canyon!> of mod­erato: relief Ele\"3llOn al the -"lie \":lncsfrom aboul 500 feel at lhe cnlrance onCorral 110110'01 Creel... to O\l:r 1.700 feCincar tlK' north\locst corner. Well dewl­oped stream drainage on the ~lle allO\\,>nunwater 10 draIn Into Corral Hollt)\ll'Creek located adpcenllo Ihe <;()Ulhernboundar) of Ihe l>lIe.

INTRODUCTION

REGIONAL GEOlOGY

S,le 300 is on Ihe eal>lern l>lde of IheAllamonl Hitb. a pari of Ihe DiabloRangl' wllhin Ihe Coa:.l Range' phy,lO-

PrOll,en ,n unde..tondong the complu geol-ogy of the Coost Ranges physiographIC provInce,nvolves a step-by·,"p approach in Ii", comp,e­hending the geology of smaller oreOI wltho" thISprov,nce By pUKing logethe' the knowledge9cuned Irom these smalf,r oreal, a c1eorer pic­lure of the Coost Ranges geology;s emergmgTh, follow,ng an,d, describe, Ill. geologIC sludy010 portIon 01 the Altamont Hill. that was con­ducted as port of the grOl,lnd water Invesltgot.on01 lowrenu Lvll.more NatIonal LaborolDrylo<;,6"fl. e>difOl"

I n 1953 officials of lhc Lll.... rcncc Li\'CT­more Nallonal Laboratory ILLNL) 10

LI\crmorc. California. selected a nearb}area 10 te~t high e"l:plosi\'es associated\111lh nuclear weapons research (Fig.ure I).

Illgh e"l:plo;.l\"cs tCl>ling began 10 1955 andha~ continued: parttck beam· fC..earch i..al,o "urrenlly being eonducled Ihere.Th" 'lie. !..nown as "S,le 300:' I' :lboUI11 'qu:lre mile, in area :lnd I~ 18 ro:ldnule, ,outhe:l~l of Livermore 111 lhe'p;lr,ciy popul:lted Allamanl Uill, of lheDiablo Range. Aboul five-l>ixlhl> of Itll~

'lie i, .... ilhin we.lern San JO:lquinCounly: Ihe remainder lic~ in Alamed:1Coullly. Since 1982. LLNL l>Ciel1li'l~

have "onducted groond water 'Iudlesbenealh the Slle al> an IIllep111 part ofIho: gcologit· 1O\'eStigallon.

CALlFOI1NIA GEOLOGY May 1990 107

....

F'gure 2. Generalized geolog,c mop of the Son Francisco 80y area showing th" locotion of Sir" 300.Key to symbols: S8, Solon,on 810ck; SAF. Son Andreas fault; HFZ, Hoyword fault zone; EBH, Eosl 80yHilt.; CFZ, Colovero' fault zone; MD, Mount Dioblo; GFZ, Greenville fault zone; AH, Altamont Hill.;TOFl, Te.lo·Ortigolilo foult zone; LV, lovermor,,·Amodor Volley lodopted from Rober and Corpenler.19831.

Paetllc OeMn

Rod., e"po~eu in the region ~llrround­

ing thi, ,ile lll'IY be cl;t~~ified into threcgeneral grollP~:

(I) Late ·!crtiary-Qllaternary. 5 millionyear, ago (myal-Hol,x'ene - alluviumand 'emi-('on'olidated ,edimenl~ ofmainly ('ontinental origin;

(2) Early to late lcrtiary. 65-5 mya ­Neroly. Cierbo, and Te~la Formation~;

~hallow m;trine and continental M::uimen­tary and voleanicla'tie roeb; and

0) Jur'I~~ic-Cretaceou~, IKO·65 mya ­Great Valley Sequence, m.trine sedimen­tury rorb: Fmncbcan Comple;\;. imen~ely

sheared and deformed l11etamorphlY.>edM:dimemary and igneou~ rock~.

The generalizcd regional di~tribution ofthese unils is presented in Figure 2.

lote Tertiory-Quoternory Units

The youngest stratigraphi(' units in theSan Francisco Bay area arc predomi­nantly non-marine sediments that varyfrom Pliocenc to Holocene in age (Dib­blee and Darrow, 1981), Older portion~

of thb sequence may be scmi-lithified;)'ounger ~trata arc largely uneonM)lidatedalluvial deposib. These ~trata arc lIlCallydeformed and even Holocene sedimentsmay be off~et acrlY.>~ major. active B;tyarea f;tull.'.

Eorly to late Tertiory Units

i

LEGENDLate Tertiory-Quoternory

Alluvium and conlinental.ediment>

Tertiory

Sediment> ond volconics Ilocolly non_marine) including Plio-Pleistocene

Juronic-Cretoceous

1m Greot Volley Sequence

c=J Fronciscon Comple><

~ Me,azoic Gronite

Tertiary marine and volcanicla~tic

rock~ are present in the immediate vicin­ity of Site 300. These Tertiary rtlCks arcmainly sandstones ,llld ~h,Llcs with "orneeonglomcrates and tuff beds. Source, ofthe volcanic a,h and detritu~ were :lIlciem"oleolnic eenter~ located where the SierrJNevad;l now ~tand, (Lerbc"mo. 1956) orcloser "olcani,' center.-. in the BerkeleyHill, ;lnd to the south (Dickinson andSnyder. 1979).

The Tertiary rocb have been moder­;ltely to imenscly deformed :IS;l result ofre('urring f;lulling lllld volcanic activity inthi, region (Figure 2; Table 1). The majorBay llrCa faull zone, influem:e the di,tri­bution of the Tertiary roe"s within thellrea. Numerou, faull~ eutlhe Tertillry'>Cquence.

Jurossic·Cretoceous Units

The Grellt Valley Sequence underlie,the Tertiary ~e(luenee ~tr.ltigf:lphieally

<lnd for the 1110,t pari ~tructurally. :lndin the vicinity of the 'lUdy arellthe ~e-

quenee i, cOI11pt)M::d of two form:ttion.,;the MorellO Shale ,Lnd the Panoehc For­m<ltion. The Great Valley Sequence con­~iSb of Illarine .'>CdinK'ntary da~tie rocksthat h.l\,e been folded and faulted but onlyslightly metamorphrn.cd. In the vicinityof Site 300. the'i.C rocb :lre ellpmed onthe f1anb of the Di;tblo Range andMount Diablo. and form the core of theAltamont Hil h nOrlh·northwe~t of the ,ite(Figure 2). Great Valley Sequence l'I)(.'j,;,.

aho underlie the San Jo'lquin ValleynOrlhe:l~t of the ~tudy area.

The eonlarl between the Great V"UeySequence and the underlying FmnciM'<lnComple.~ is eon~idered to be:l falill. re­ferred to as the Coast Range thrust (Dick­inson, 1965). Structural re1ation~hips

:llong the Coa,t Range thru~t arc C(lI1lPk.~

uue to later reactivation of the thm't byhigh-angle normal and 'trikc-~Iip faultnUl\'cmelll. The Tesla and Ortig'Llila f,lullsare ellample~ of ~uch stru..:tur.tl compl ica­tion~ thlU oc..:ur in the vicinity or thestudy are;t (Raymond. 197J).

The Fmnci\Can Complcll b eompo~cd

of v;lriably metamorphosed ~edil11ent:lry

rods that r:mge in cOlllposition from:lrgillite to eonglol1lef:ltc and maficigneoll~ rod~. The~e HlCk, form <ll>lruc­tur.llly emllplell and heterogenous unit.The Fr.sn('i.,can Complell forms the base­ment rod in llllY.>t of the eentr.sl Califor­nia C{)il~t Range, lmd, in the vicinity ofSite 300. i.~ ellpo\Cd in the core of theOi,Lblo R'lIlge to the ~{)U1h and at theMllunt Diilblo picrcement to the north­we.~t. Where expo.'>Cd "Outh of thi~ \itc,thcM:: rcx:b ,Ire ~tfOngly deformed gmy­wac"e, grcen~tone, and chert. .... ith Ic~~er

alllLJunh of sh:lle and phyllite. The rocbare Ilrk'nted ncarly "ert iclllly or dip~tecply 10 the north-northeast. OeclUse ofit, CIJIltplellity. no :!C('ur.sle stratigmphi(,thickncss lor the Frand-.can Com pie", h<l'been e'tilllated.

SITE GEOlOGY

Site 300 i~ IlK'ated within;l ~erie, of'teep canyon, and hilb. Bedrock b CO\1\'

108 C"t1FORNI" GEOLOGY MO~ 1990

Plloto I. Aenot ~,ew of Lowrence Lovermore Not'onol Loborotory SlIe 300, frOM on olhtvde of 15,500feel. Photo 'oken October 10, 1988. North .. 10 Itle top. Corral Hollow Creek, which cronel the centerof 'h. pllo'o from left to ngllllorms the southern boundory olthe s'le.ln'erilote H'9l1woy 580 ando por' of tile Cenlro! Volley are 01 the upper "9hl PfIoto by Air Flight Servoces, Santo Cloro, CoJr/orn,o.

po..ed of Plto·M t{)l.'cnc vO!c3nicla..ltCruck, Crclaceou, '>C(lirneIll3ry rock, andunderlyin!; Ju ......, .. iC-CrClaCCOll' ba~I1lCnl.Alluvium III lhe :lre:l is prcdonlln:uulylerr.ll:e dcpo.. il\. collu\ium, .mll rJvinefill. The gel)logic .. lrUClUre 1" comple;l(becau\C \C\er..11ll3jor fold, and \C"crJIfaull\ occur bencath the ,tiC (Figurc 31.

The geology of Stte 300 t.. based on re·ginnal geologic mapping. b) lIuey JJWK).Raymond (IWJ9). :!nd Dibblee (19KOa. b.c. and dl...upplemented b) ob'>Crvatioll~

made durll1g detaileo.l hydrogeologIc "lUd~

ies of portIons of the ,ill' c\)uducted inrecenl yea.... b) LLNL (Raber and Car~

l>enter. 1983: Carpenter and others. 19K);Buddemeier. 1985: Carpenter and other"

19K6; and Carpellier lllld \Jlher.. , 19881.Phol" I " ,III aerial \ Ie .... of LuwrelK"eLiverillore NallOflal L..borJlury Sitei()}, 1:lken from an .1Iltludc of 15,500 fecI.

Strolograph)'

Uncon.."lidatcll (!epn"t' III lhe 'Iud)urc:! lIre 1'le"'lOccnc IIJ lIolucclle In ageand con".. t of collu\'iulll. allu\ lum, :1I1dravine fill IQa); land,ltllc dept"'lh (Qh);ano.l tcrrJce or nl(ler .Illt" IUIll, IQnal (l-tg.urI' ,\), Colluvium. :lllu\ tum. and rJ\ IIlCfill material, \~o.lf) from ..iltyda) .. 10 ,til)gra\eh; thtt'kne'M:' l)pically '<Iry frolllI.cro :tlbedrod.. tlut,'rops III 1.1.5 feetTerrJce depo"lh arc lllO'ot e;l(ten\llC III thellOUthcrn part nflhe SIlC norlh ofCorr.J1

lIullO\\ Crc...L and ("onsl'l uf ,andy ,tl1 ...<lnd clay.. gr.lding downward to sand, :tIldlocally \·o:tr'>C cubble·.lIld·boulder·bcartnggr.J\el... Thc'>C lermee, range from 3 to 30feet thick

An unn.lIned Pliocene unit (Tps) con·.. t-r .. uf non·marine conglomcr;ll"'~ wilhcobble, of angular grJywade and chert.":Inll.. lnne" and red. green, and !;.....yd:l)' Thi, unit occur.. on Iwlaled hillhlP"a, remnanl\ of a once t·ontinuou.. blankeluf ~dIl11cnt. II ..1'>0 has been ell("ounteredin Ihe ..ub..urf:!(:e beneath lhe .'>tlUtherlyP:lrt of lhe ,ne. Crcr....-bedded ..;lmblOnesof lhe Tp, unil oceur near Building 834 til

the s(lUlhcaM porI ion of the .. lie (Photo 2).

The bedrock underlying most of the,tully area con'*" chiefly of the conli·nenl:!1 and eSlu:lrine. largely vO!c;lnlc!:ls,ItC. :.cdimentary roel: of lhe MioceneNeroly Form:!tion (Tn). The Neroly For·m'llion. up to 450 fcetlhicl:, IS composedof disllnctlve blue·we;llherlng .sandslones;tnd .. iltslOnes. coar~ conglomer.Ltes ofwell·rounde(l andc,itie and ba..allic peb­bles :md eobbles. and interbedded luffa·ceous sh:lles. Fraclures afe common. IIview of lhe Neruly Formalion ~tr.Jli·

gmphic ~ction ncar Building 826 iiishov.n 111 Photo J. Above the Neroly For~

m:niol1 is lhe Pleistocene ·lillar... Forma­lion (QIl) ~:lnd..lonc, A '11I:t1l outcropoccur, imllledi:llel) cast of lhe site. Con·fornl:lbly underlying the Neroly Form:.·tlon arc illlerbeo.l(led. coarsc-j!r..mcd.friable ...and'lones. earbonaceou... brown..hale.... and luff.. of lhe m:!rine. lowcrMioccne Clcrbo Form:ttion (Tms,j. Sand­.. tones of thl' Cierbo Formallon cum·monly appear yello" 10 browni'h gr.tytil borclmle cUllings. The~ nueaceou:..quarl/-fll'h. :lnd p)rtltc ...1ndsloncs arcchar.M:teril.ed by a high degree of sorttllgand lhe pre'\Cnce of wcll'rounded chertl;lCbblc,. The formal ion ha.. an :!verageIllldne.... of 300 feel in lhe 'ludy area.

The Eocene Te'ila Fllrlll;l!tO (TI.lI) I' e.~­

~d ">QUlhwe.. t of Site 300 and along lhe"OUlhcrn l11<lrgin of the .. tte. It uncon­fortlwhly underlie.. Ihe Cierbo Formation:md rrobabl) underlie' other parIs uf the..He at dl·pth. The li:,I:I Formation i:. <lheterogenou, '>Cqucnce of bruckish I'o.:llcrand marillc ,e(limenlaf) mels of lalL' Pa·INK·enc tn e:lrly I::ocene age. The unll i~

1.200 10 1.500 fcetthiek "here e"po-.cd~Juth \Jf the 'ludy area, III lhe northernarea of the 'lie. Cicrbo Forrnatiou rock,arc directly underlain b) Great Valleynx:J:...; thu, the Te,la I·orlllatlou h:l~

pmehed OUI or 1m, been eroded frulll rh"area.

CALlfQl!NtA GEOLOGY Moy 19'90 109

Photo 2 View 01 Cro$s·bedded sondllones of Ihe unnamed Pliocene (Tptl ul'llt View II to 'M nOrlheoslat BUIldIng B34 of 'he EnVironmental Telt Area Photos by Neil B. Crow. October 1989, ...cep' as na,ed

'"~

.,. .- -',~, -~

'"~• .

. .' ,

~~, .........~ ... ~, ,0

.~- "~..-:.~.

.'

" '","

I

The Upp.::r Crcl:lceClu, Gn:al Valley Se­quence \lndcrlie~ Site 300 'II depth and i,(-{)mp'(I~cd of the Moreno Shale and lheP:lI'lol:he Formation. Rocb correlaledwith the l:>;lIloche Formallon arc eXJl'O'Cdlocally in lhe northern and .... e'tern I>;!rl'ufthe ~ite. The Moreno Shale ha~ nulbeen recogllll.ed within Site 300 ibdfOn a reg,onal hasi" lhe Upper Crcl.leeoU'Moreno Shale (Km) i" cornpoo;cd prnnar·il) of poorly bl:dded. crumbl). green-to­gr.ly ,hale or mudstone of manne origin.and comformably o\'erlle~ the P·.l.nocheFormation (Kps). The lhid.ne,~of theMoreno Shale 1Il the vicllllty of the 'lUdyarea is Inferred 10 be in exces~ of 1.000feel. The Panoche Formalion I' a thicLturbidite M:quencc of intercalaled arLo,iesandslOne. micaceous ~hak. and locallenses of cobble conglomerale. It, lhlcL­ne!t~ benealh the !tile is unLnown.

The Jur.l.!t~ic-Crelaceous Frnnci,canComplex (fs) i~ e"pm.cd in the DiabloRange soulhwest of the 'lUdy are<l andI' composed of graywacke. grcen~lOne.

cherl, and lesser <lmount~ of ~hale andphyllilC. The rocks arc intensely folded.fractured. and ~hcarcd.

Structurol Relotion$hip$

The bedrod. ~lrueture al the site i,dominaled by lhe Pallerson amicline.whIch trend, west·norlhwestleasl·SOUlh­caM where 1\ crosses lhe ccntr.l) portionof the ~tudy area (Figure 3). The Terllary

'>Cdimenlar) rocL~ dip gently to moder­alely lhroughoutthe "lte except for lhearea ~)uthwe"l uf lhe CarnegIe fault althe <;()ulhwc'l parI of the ~lte \,\ here lheorienlation of the beuT<l\:L -.cquencer.lnge<; from ~~rt,c.sl 10 locall) mer­lUrneu. South of the anllehnal riuge. lhe

bedrock <;/,."<Jucnee dips tov.ard~ CorralHollow. North of Ihe ridge cre~l. bed" dip1000ard Ihe northeast an a\lCrag~ of 10degrees inlo lhe trough of a ,ub~ldlary

syncline thaI crosse<; the northe<lsternportion of lhe ~it~. The anticlinal <lndsynclinal axes plunge soulheast.

TABtE 1 FAULTS ADJACENT TO SITE 300 (Rober ond Carpenler. 1983) •

o.ltonc:e Probablefrom S,te JOO 'eng'"

fault mile, m.lel

Bloc. Bune , 11.8

Callahon 0.' "Corral Hollow 0.1 ,.,

Mldwoy 1.1 '.0

Poller$on PallT'ulo

Unnamed··

0.'0'

0.'

"18.0

51

Summory des",plian

ThruSl fault, offsets Plell'ocene Tulare Formation. concealed by younger alluYium. No ear1hquake ep,cenlerdata available.Zone 01 small faults. grades into Calc'le·cemenTed 10fnts WITh nO dilplocements. concealed by Iand'llide andalluYlal depoltls. No olloc,a'ed selsm'Clly.Offsellsyncline contaln,ng Pl,ocene strata 0.4 mIles right lateral. buried by alluYlal depo$itl w,th,n COffalHollow, PrOlecTed into Livermore Valley by early wor.ers. confined to area northeast of acti"" Greenvillefault by athefl. No assoc,aled SeISmICItyReported to have offset of a PleIstocene eroSIon surlace a"oSl.t and calculaled low geologIC Iltp rOle of0.05 mm/yr ba$ed on lhe obse.....ed offsel Thll is on order of magnItude tower Ihan $lip roles !hal havebe"'n eSllmaled lor aCllve faults olong lhe ealle.n ma'g,n of lhe Livermore·Amador Volley well of S,te 300,and II two 10 three orders of mog""vde leSilhan lhe geolog.c $lip rOle lor the Son Andreol fault Iyslem Afew of .he diffu'e seISm,c .....nts delec'ed by Ellswar1h and olhers. 1982, dum.g the peflod 1969_1981 we'ecentered near The MIdway laull No Slgnlficanl h,stonc eo"hquohs have be.n closely ossoclaled wl,h lheMldwoy fault.Bedroc. fault WIth,n Altamont HIlls, NE lKle up No olloclO1ed leltmlcltySeparate. franCIscan Compl.... COfe of Ooablo Range Irom Gre01 Volley Sequence and younger rach ,nAltomont Hills; probable remnanl 01 CoolIRonge lhrUlt Truncaled by oclrve Greenville fault at welt end;IntersecllOn WIth oc/lve O"'9O'ilO loul, ollOUlheol1 end 1$ lhrough comple~ $e"el of foulll wllh varying ori·en'allon$ and lectonic styles. Regorded 01 ochve but nat spatIally allocoated WIth earthq\lOke adlv,ty mani.tored from 1969 10 1980.Normal bedrac. fault wlll"n AI'amonl H,li" NE side up. cOl'>Cealed by olluv,al depoSlII 01 POllerson PassRood. No a$socoale<! leismicity

·c....~ I;I~ R..... f,.I" --L..........s 1..11 ., S~o "10 ... .I1... ~'<oc<lI.. 'M k" •..J ... _ """.I I. r.t>k I• °Th" I t, " .IlftO".' r",,,, I..... ,l nIC<I t.._" ot S~. 'OlI

110 CALIFORN'A GEOLOGY Moyt99Q

..,....

.......

._-•,"....

'"

",,,-,I,

..

.~'," "'" .~ .. , ~

\"-:(

Tm...;.-,

'"..

f "."11IO1, ..._"""'001I

'"

II .....

..~".,.

...\.

TL!!!' i<" -00.0

-2 I(m !!"." I(m po Tpo 7

•"- "" •Y-:i,,-'-...!~'N')::: ~~!i:::::;'~f.k~i;...t. ~~- '""" '"':: ~

''''-!6;'''';::-,,,,~·!'~·!"~I-;..;;!=-:r..~"~-;",·!::-;.-:~\";";''''";-..,~;;;?:;;iii··~·i·-;';': ..,.,.",00;,.._..,'!"~f:_-;~;';"1J..",!.~¢:>';;~',7,::''';;''::!''''''''"._ ".._ .,__ "__ "__ .' ...._ .,""_ "... " ..._ ,'....... '1.1,._ "."'''' " ...._

...,,"'"

.....

.....

..,..-

._-

:'5l. oyerlurned'D...,91

t,' Ie

~ U__ -,;;;. r ••••••••••••~ D'

-------------------------------------------Do.hod where g'(IdohonoJ or oppro,,,motely located

'.

Contod

Fault

Do,hed where ,nlerred; doned where concealed. quefled whe'e e~lsr·

ence doubtful; double arrows Indicote IInke·ll,p movement, U­upth,own IIde. D~ down. thrown SIde, 'elotlyely.

Ax.. of fold +---------------- ------_ ont,cl,ne

--------------------t-- sync~neArrow on aXI, IndtCate. d"eetlOn 01 plunge

St,i~e ond dIp ol,t'ata'<..5 ,ndined '<. indined

(app,oxlmote]

EKPlANAT'ON

Quaternory

Tertlory

}J",,,,,.CrellKeou,

Ple,slocen"

Holocene

Pliocene

u"'~C,e'oceou.(Grear VolleySequence)

M>oce"e

,,-----,',-"'--------------------------------------,, """~ Allwlum }@U Landsl,de deb".

IQ~ I Old". oll\IYjum }@D Tulare FormatIon

~ Nonmanne

}ledimentary rocks

~ Neroly FormOllon

~ Gerbo Form<;lIIon

~ 'edo Formor,on

l~ Moreno lhale

~ PonCKhe Formo~o"

IT] F,onC'Kon Complex

f,gure 3. Topogroph,c and geologIC mop of S,te 300 and geologIC «OSHec"on AA-AA (modified from C,bbl.., 19800, Raymood, 1969, and Robe' ondCa,penter, 19831, U.S. GeoloQtCol Su....ey quodrooQles (Ceda, Motlnto,n,lone I'ei! Creek, M>dway. Teslo, ond I'ocyl_

CAlIfORNtA GfOtOGY May 1'1'90 111

Pholo 3 V_ of MIocene Neroly Fo,moroon .r,ohgrophic: 1e<llon neo' BUIlding 826 01 _tIl·cenlrolporl of Sole 300. View IS to tile nor1t>.

Seismicity

eate faulting in the Quaternary allu\ lumThc lack of such fealurcs indll;atcs anabsence of l>lgnifieant actiYlty along lheCarnegie fault since al lcast late Plelslo­cene time (Carpenter and I)eifer, (983).

Distribution of Regionol Soil Types

Soils at Sile 300 are c1assined as "soilsO\<er bedrocl in the hill) and mountainousarea," (Cole and others. 19·U). Threepnocipalwilt)pcl>. :tIl members of theLinne senes. occur hcre: (I) Linne adobeclay (In): (2) LinllC clay loam. roclout­tTOp pha'iC (Ler): and (3) Linne adobecia). steep phaJ>C (LOl). AII three soiltypes arc typically d:trk bro.... nbh-gmyand calcareous. The linne adobe c1:t)and Linne clay loam rock outcrop ph:ll>Chave al>OlIIcwhatlighler. strongly calcar­eOUl> subsoil, suggesting some .'tOil profiledevelopment.

In the surroonding. regKm there arcM:\'en faulK Two of thc!.c faults -theTesla and Midway faults - arc consid­ered 10 be potentiall) acti\'C (Raber andCarpenter. 1983). II0000e\'er. no signlfi­canl historic earthqualeo> ha\e been asso­CIated .... Ith the Tesl:t or Mid.... a) faults!Table I). TheM: faults are of linlltedexlenl and ha\'e dl'placed M:dllncnb ofPlio-Pleistocene age. Hov.c\'('r. there 1<'

no C\ ldence thatthc) displace IiolocenedePOSIlS In the area.

T.... o deeper aqUifers exist maml) be·neath the >;outhcrn part of the ~IlC, ThcseCon~ISt of3 water-table aquifer* 111 sand­stone" that COlhlllutc the lOIOoer portion ofthe Ncrol} f-ormation. and a deeper. con­fined aqulfe~ that currentl) prO\ ides the....-ater suppl~ for the LlNL faelht)

HYDROGEOLOGY

the Grecn\llie fault. located about 5 111IIes"cst of Site 300. Thus. the pnn('lpal scis­rille hazard atlhe l>lte would be strongground shal1l1g caused by an earthqualeon the Greenville fault. A strong earth·qual';: eM, =5.8) occurred OfT Januar) N.1980. on this fault. This earthquake ....~J,strongl) felt at Sile J<X) but did not result111 an) structural damagc to "Ite faellllle!>and non-\trueturJI damage was negligibleIRabcrand Carpenter. 1983).

Ground water il> present beneath Site300 in l>C\'CrJI hydrogeologic:tl sellings.Scvcmlshallow. perched water·bearingzone!> of limitcd Imeml and vertical e~len1

have been identified during engineeringand elwironmel1lal studies. These perchedlOnc!> occur within channel deposit.\. of10100' to moderJte permeability presentwlthll1thc Pliocene to Iiolocene non­manne SI.-qucnce and within froteturedrocl\ of lhe late Miocene 'COI} FormatIonThese perehed lones ~ kid little water toobservation wells and do nol constItutepoIentlal .....aler-suppl} source....

-,...CAUfOll:N1A GEOLOGY

A short unnamed fault tre1llh approxi.m:uely north-south through the MJulhe:lstpart of the site (Figure 3). Less th:m 25feet of verticalmo\"emenl has nct'urredalong this fault in beds of the NerolyFormation. Thh faull has no geomurphJ(~

expression and is buned by Quaternaryallu\'i:tl dcposits, indicallng that 11 hasbeen inactive slnee late Tertiary tlllle(Raber and Carpenter. 19IB). A ,m:tllthrust fault cUIs the Neroly 1'lInnallon:1lthe >;outhcast part of Slle 300 IPhtJlo 4).

SIte JOO 1\ 1000:tted on the ea\tern edgeof the M:lsmieall) -31.'11\'(' San FrJocil>C'o8a) area. 1I0000c\"Cr. the fault~ at Sue.300..hoY. no cvidence of Iloloecne dlspl:Ke­menl. and thus lhe ~Ite 1<' 1'01 \Iolthll1 aSpcci:tl Stooles Zone undc~ the Alqulst­Priolo ACI (Slate of California. 19721.Map faulls of the San Andreas s)stcmhaw rcccntl)·actl\e sc1!menl\ In thc Bayarea; the nearest of these to Site 300 ISos« ,""""

111

Two prindpal faults occur within SiteJ<X): the Elk Ravine f:lUlt in the northcentral p:lrt of the site. and the Clrnegiefault which erOlol>CS the l>Outhwestern partof Site 300. The Elk R:tvine fault trendsl>outheaslCrly :lIld. :lllhough a detailedl>tudy has not been performed. it appearsto terminate to the soulhcasl. Localizedfault splays and cro!>l>-f:lUltl> wcre idenli­fied by trenching and field mapping atthe northwestern end of the fault (lloff­man. 1988. Taffet and other!>, 1989). Thefault olT!>Ctl> beds of the Neroly Formation:11 Site 300. T"'o trenches across the faultuncovered no evidence of faulting in thealluvial fill and no olher eyidencc of Hol­OCCIlC dlsplaccmcnt (Carpenter and Pei­fer. 1983; Hoffman. 1988), 1III,.'Iplcnt soilprofiles de\"elopcd o\'cr the fault indicatethlltthe mmimum agc of displacement ISbctwcc.n 11.000 and 20.000 ycar!>, TheCarnegie fault merges north .....est wllh theTesla-Qrt1gahta fault (Figure 3). and withthe Corral Hollow fault southeast of Site300 (Dlbblee. 198Ob). Trenchmg. map­pmg. and Joggll1g of late Tertiary !>Cdl­mcnt:IfY rocls and Quaternary allu\ ialdeposllS In a location 31.-ross the Carnegiefault did not re\eal any features to Indi~

PhOlO 4. View of ° .mollthrvst foult cutting on out­cropofNeroly Formolion. View is To the north neorBuilding B79 ,n the Generol Services oreo.

SUMMARY

Much of the ea~tcrn Coast R'l1lgcbetween Subull Straits and Coalinga bunderlain by b:I.'>Cmcnt rocks of theFrunci~an Complex and GrC:11 V.tlleySequence: bceOluse of deform:llion, thegeology of these rock unit~ is difficult 10

intcrpret. The study areOl is underlain byextellsivc bedded Terti.lry M:dimemaryrock~ in which open folds havc developed.Thus, local str..atigraphy and structuralgeology can bc inlerpreted more e:l~ily

th:1Il in many other CO:L~1 Range loca­tions. The inve~tigations were dc~igned

primarily to determine the horizonlOll al\(Ivcrtieal extent of any possible contamina­tion in ground water from operations atSite 300. In order to under~tand the ~ub­

surface structure, it wa~ necessary tostudy the regional geologic sclling anddewils of the geology of the site.

ACKNOWLEDGMENTS

Thc author~ th:lIlk the following indi­vidual~ who l'Ontributcd to the unJcr­~lanJing of Sitc 300 geology and to thepreparation of thi~ report: Penny Web~lcr­

Scholten of LLNL and field gCill()gi"l~ ofWei.\s ASM>Ciates for their proficient geo­logic logging of borcho1c~: Willi.unDugan of San J~ State Uni\'er~ilY formapping the Elk R<I\'ine falJh: J.lllC WIth­erell of Kirk-Ma)'er. Inc. for editorial~upport: Kim l-IeywarJ and Chris John"Ollof LLNL for drJfting ~upport: DonnaHarms of LLNL and Jan Tweed of BendixFor clerical assistance: and Bern QU:II·

heim of LLNL and Ken Toney of Broymand Caldwell Engineers For eomputeril.cdpreparJtion of borehole geologic logs. Wealso wish to thallk Fredric Hoffman :.IndWilliam MeConaehie of LLNL for their

overall guidancc and dir<,ction for ourstudy of Site 300, and their peer reviewufthi~ article. Eugene Dr-liley, J:lllle~

L:lI1c. and M:lrjurie GOIJl.alC/ of Site 300.t1so provldcd ,uppurt of our I'ffllrt~.

This work was performed under the'lUspjce~ of the U.S. Department uFEnergy hy L:lwrenee Lll'ermOre NationalL;Jboralory under cum met No. W-7405­Eng-48.

Glossary

canfined aquifer: 0 permeoble body of rockbounded above and below by impermeoblebeds.

water-Iable aquller: a permeoble bodyof rock bounded below by impermeoble bed,.

partide beam: .ubotom,c part,des, ,vch osel«lrons, pOSllrons, ond proton.. ore occeler­oted to high energies ond velocities andfocused inlo beams. Such beoms ore meosuredin terms of billion, of electron volts,

REFERENCES

Buddeme,er, R.W., Rugg,ero, M.R., Corpenter,D,W., ond Young, OJ., 1985, Investigation oflritium in groundwater 01 Site 300: lowreneelivermore Notionolloborotory, livemore,Coli/ornio (UClD·206oof.

Corpenter, D.W., ond Peifer, D.W., editors, 1983,Supplementory Ooto Report, sae 300,Chemical ond Hydrogeological Assessment:lawrence livermore NationolloborOIOry.livermore, Colifornio IUCID·19801).

Corpenler, D.W., Slone, R., Rogoini, R.C.,McConochie, W.A. Crow, N. 8., ond Elwood,R., 1983, Assessment 0/ the edent of Trichloro_elhylene contominohon of soil ond WOler 01

lowrence livermore NotionolloborotorySite 300, lowrence livermore Nationollob­orolory, l,vermore, Colifarnia IUCID·t994S),

Corperoter, D.W., Elwood, R.. ond Gro.., l.G.,1986, Assessment of lhe e~tent of Trichloro·ethylene in so,1 ond woter 01 lowrencel,vermore Nationolloborotory, Site 300(Report 0/ Progress in Investigolions):lowrence livermore Nolionallabarolory,livermore, Colifornio (UCIO·20n 41.

Corpenler, D.W.. lomorre, A.l., Crow, N.B., ondSweorengen, P.M., 1988, Closure pion lor theDecomm,ssioned H,gh bplos,.es Rinse_Water logoons or lowrenee lovermoreNOhonolloborolory S,le 300, lowrencelivermore Nohonolloborolory, livermore,Col%rnio (UCID·11369)

Cole, R.e., Koehler, l.F•. Eggers. Fe., ond Goff,AM., 1943, Soil.urvey, lhe Trocy orea,Coloforn,o: U.S. Departmenl of AgrICulture,Wosh,nglon, D.C., Series 1938, No.4, 95 p.

D,bblee, TW., Jr., t98Oo, A preliminory mop ofThe M,dwoy quodrongle, Alomedo ond SonJooquin counhes, Coliforn,o U.S. Geolog,colSurvey Open_File Report 80·535.

D,bblee, lW., Jr. 1980b. A prelim,nory mop ofthe Cedor Mounto,n quadrangle, Alomedaand Son Jooqu,n covnlies. Colifornio: U.S.Geolog,col Survey Open·File Report 80-8S0,

D,bblee, lW., Jr. 1980c, Prelomonory geolog,cmop of the lone Tree Creek quodroogle, SonJooquin County. Coli/ornio: U.S. GeologicolSurvey Open.Fjle Report 80·S66.

Dibblee, lW., Jr., 198Od, A prellm,nory mop ofthe Midway quodrongle, Alomeda and SaoJooqu,n counl,es, Colifornio: U.S. Geolog,colSurvey Open.File Report BO-535.

Dlbblee, lW., Jr.. ond Dorrow. R.l., 1981, Geol­ogy of the northern Dioblo Ronge ond lover_mOre Volley Orea in Geology of centrol oodnorthern Dioblo Ronge, Californ,o, Frizzell,V., editor, Pocific Section of SOCIety of Eco­nomIC Poleootologists ond Minerologrst1,lo, Angeles, Coliforn,o. p. 77·112.

Dick,n,on, W.R., 1965, Folded thrust conroct be­tween Fronc05con rocb and Ponache Groupin lhe D,oblo Range of centrol Coliforn,o;Geologicol Society of Americo, SpeciolPoper 81, p.148·249.

DICk,nson, W.R., ond Snyder, W.S., 1979. Geome­Iry of Tripfe Junctions relOled to Son Andreostron,form: Journol 01 Geophysicol Reseorch,•. 84, p. S61·S71.

Ellsworth, W.l., Ol.on, JA, Shijo, LH., ond Mor*',S.M., 1982. Seismicity ond active faults in theeosTern Son Froncisco Boy Region in Horl,E.W., Hirschfield, S.L and Schulz, S.S.,editorl, Proceedings 0/ the Conference onEorthquoke Hozard. ,n the Eoslern Son Fron·cisco Boy Areo: Colifornio Division of Minesond Geology, Speciol Publico~oo 62, p. 83-92,

Hoffmon, F., 1988, Foult Investigolion 01 Pitl,llNl Site 300: feller to Michoell. Higgin.,Regioool WOler Quolity COnlrO! Boord·Cenrrol Volley Reg,on, December 15, 1988.

Huey, A.S., 1948. Geology of the Teslo quodron.gle, Coli/ornio: Colilornio Divisioo 0/ Mine.,Bulletin 140, 75 p.

lerbekmo, J.F., 1956, The chorocter ond originof lote Tertiory Blue Sond.lone. in centrolColi/ornio: Ph.D. dissertat,on, University ofColi/ornio, Berkeley, Coli/ornio.

Poge, B,M.. 1981, Sequenliolgeologic ,ndicotorsof plote interoctions. cenlrol Colifornio: E.O.S.Tron.oct,on. 0/ the Amerlcon GeophysicolUnion, v. 63, no. AS, p. 911.

Rober, E., ond Corpenter, D.W., ed,tars, 1983, Anevoluotion of the hydrogeology ond groundwoler chemistry ossoc,oled wirh londfills 01

llNl's Site 300: lowrence livermore No·tionolloborotary, livermore, Col,fornio(UCRl-53416j.

Roymond, LA, 1969, The Slrotigrophy andstrvcturolgeology of the northern tooe TreeCreek ond southern Trocy quodrongle" Colo·lornio: M.s. TheSIS, Soo Jose Stote College,Son Jose, Coliforn,o, 143 p.

Roymond, l.A., 1973, Teslo·Ortrgol,to /oult, CoosrRonge thrust foult ond Fronciscon meto·morph"m, northweslern Dioblo Ronge,Col,forn,o, GeologiCol SOCIety of Americo8ulleton 8A, p. 3547·3562.

Srale 01 Cahlorn,o, 1971, Speciol Studies ZonesAct: Coliforn,o Publ,c Resources Code,Secllon 161 ond follow,ng.

Taffel, M.J., lomorre, A.L, ond Mctlvnde, WA,1989, llNl Site 300, Env"oomentollnve.t,·gor,ons Quorterly, Jonuory·Morch 1989:lowrence lIVermore NOlionollabororory,llverrnore, Californ,o (UCAR·l0194·1·89!.

CALIFORNIA GfOlOGY May t990 1lJ

A Page for Teachers

Source Materials for Earth Science ProjectsEach year thousands of students in the Uniled Stotes prepare science projects to be entered in science fairs. Many source books and articlesore available in libraries to help teachers and students in planning and orranging science fair projects. Some reference materials for preporingprojects are listed in brood categories. A brief annotation is included,

GENERAL SCIENCE

Gutnik, Mortin J., 1980, How to do 0 leience projecl and report FronklinWaus Inc., New York, 63 p. An excellenl discul"an of Ihe IcienTificmelhod

Loiry. William, 1983, Winning wilh Icience: loiry Publishers, Sorasolo.Florida. A gu,de for junior and .enior high Ichool Sludents ,nvolved ,nscience fair competitionl. Liltl programl Igranls, Iripl, and employment)available in lhe Uniled States and abroad.

Nal,onal Science leochers Associat,on, 1985, Science fairs and proillcts:Washington, D.C. A collection 01 artides orig,nolly published ,n Scienceand Child,en and SCIence Teache.

Saul. Wendy, ond Newman, Alan R., 1986, Sc,ence fore: on illustrated gu,deand catotog 01 toys, books, and octivities for kids: Harper & RowPubloshers Inc., New York. Coverage indude, museum programs and Ici­ence lairs and compelitions. A guide de,igned for leochers and porent,who adVISe ,tudents.

Science act,vitie,. quarterly pe"odicot, v. 1. June 1969 to datil: Hllld,lIfPubltcahon" 4000 Albermale Street, NW; Wa,hinglon. D.C. 20016A ,ource of expe"ments, &xploralion, and prolect. ,n the biological,phYlical, ond behavioral.c'ence'.

Science lair project index, 1981·1984, 1986, edited by Cynth,o B..hop andDeborah Crow&: Scarecrow Press, Metuchen, New 1e"ey, 686 p. A sub·IIKI index to books and magoz,nel lor student. and teoche.. covenngearthquake., volcanoes, erosion,lossil., glocie ... rocks, sond, and ,lap&1lphylicalgeology).

Tocci, Salvatore, 1986, How to do a science 10" prolect: franklin Wanl Inc.New York. 128 p. hcellent information on chOOSIng a topic, doinglibrary releorch, wril,ng a science reporl, and presenhng lhe prolect.

GENERAL EARTH SCIENCE

Chollond, Helen, 1982, Act,v,tie. in Ihe earth SC,enCe.: Childrens Press,Chicogo, Illinois, 93 p. A book 0178 ..mple octivilie. that demon,troteearth science concepls. Grode. 5 and up.

Cvoncara, Alan M., 1985, A lield manual for the amateur geolog"t, 1001,and ochiliel lor exploring our planet: Prentice·Holllnc., EnglewoodCliffs, New Jersey. 258 p. Teoche. how to observe and .nterpret rocks.Mops, mu.eum., and geologic feature. 01 not, anal pork, are ,ncludedHigh schoollhrough odull readers.

Garon, Marri., 1967, Experimenral earth sciences: Howard W. Sam. &Company, Indianapolis. Indiana. Sixty .imple experimenl' illu.rrare ba.,cprinciples 01 meleorology, oceanography, and geology.

lambert, David, 1981, Act,ve earth: lorhrop lee, and Shepord Books. NewYork. homlne. the 10rce.thoT have .haped earth. Include. ochit,e. andexperimen15.

lambert, David, and the D,agram Group, 1988, Field gu,de 10 geologyFocls on File Inc., New York, 256 p. An excellent basic reference ra rhelield 01 geology. Comprehensive ,n coverage and h'ghly illu.traled tohelp readers quickly grOlp concepts.

Soolin, Harry, and Soohn, Lauro. 1965, Thll young expe"menter'. won:·book, treOlure. of the earth: W,W, Norton & Compony, New York. 59 p.More rhan 50 experiments "sing .imple, ,nexpen.ive equ,pmenr arepre,enled. Grode. 2 thro"gh 6.

Slone, Harris, and Ingmon.on, Dole, 1969, Rock and rills: a look 01 geologyPrenllce·Hall Inc., Englewood Cliff., New Jersey, 70 p. Pre.ents article'and exerCISe, on varying o.pects of geology: geology and chemlSlry,melt" abra,ion, permeability, and superimpOltrion, poro.ily, andhydrol,on.

Taylor, Fronk D., and Artuso, Allred A, 1989, hplor;ng Our env"onmenl,science tasks: love Publi.hing Compony, Denver, Colorado, Section. onrocks.•oil., mineral" and falSi Is, as well as on 0", eleclricily, heal, lighl,so"nd and water,

lyler, Ro,e, and Ames, Gerold, 1970, Secrets ,n .tone: Four Winds Press,New Yon:. Inlormoloon on the compo,ition of .Iones, C'V"ol., andh"nl,ng lor fo,,,t•.

FOSSILS AND DINOSAURS

800th, Jerry, 1988, The big bealt book: dino.ours and how they gollholway. Brown Bag ,e"es: Liule, 8rown and & Company, Bo.ton, 117 p.An inlrod"ction 10 dina lOurs wilh in.truction. for related project•. Forelementary grades

MocFolI, Russell P., and Wollon, Joy C, 1983, 2nd edir,on, Foss,l. for omoleurs:a guide to collecting and preparing invertebrate lossil.: Von No,trandReinhold, New York, 374 p. General diSCUlSion of poleonlolagy, plulgu,delines for p1onn,"9 fiekllnps; u.;ng topographIC and geological mop.;and collection, preporing. deoning, catolog,ng, and di,ploying lo"ils.

Moody. Richard. 1986, Fo"as: how 10 lind and identify over 300 genera.Macmillan Publi.hing Compony, New York. 1986, 192 p. Step·by-.tepapproach to 10",1 colllKl,"g. High schoolleve!.

Rydell. Wendy, 19B4, D,scove"ng fo"ill: Troll Publishers. Mawhon, New Jer­.ey, 32 p. S"mmanZel how man first come 10 understand the importanceof 10",1. and how scienlists dole lo"il, and identify mOlChing rock layers.Describes how to lind lo"il" the 1001. lhot will be needed, and how 10identify fossils thai are found.

ROCKS AND MINERALS

Brown, V,n,on, Dov,d, Allan, and Stork, Jomel, 1987, Rocks and mineral. ofColilornio. Jrd ed,lion, Nal"regroph P"blt.~ers Inc., Happy Camp, Col,·fornio Pravide. inlormolmn On rock and mineral collechng. Quadranglemops .haw,ng rock and minerollocarions are ,nclvded. High school level.

Fichter, George S., 19B2, Rod. and mineral.: Random Ho"se Inc., NewYork.tdent,fie. cOmmOn rocks and minerals. Early elemenlary grade.

Gon., Ramo, 1984, Rod collecling' Thoma, Y. Crowell and Compony, NISWYork.lllu.lroted book on rock colleCling. Eony elementary grade•.

Gilbert, MJriam, 1971, The science·hobby book 01 rock, and minerals: LernerPubhcahons, M,nneopolil, Minnesota, 47 p. Tip. on ,Iorage and recordkeep,ng for a collect,on 01 rocks and m,neral•. Grode, 6 I~ro"gh h,ghschool.

Kindle., Coral E., 1986. Dig ii, a dIChonory of fee·bom rock colilScl,ng .ite.open to omote".., 71~ edil;on, C.E. Kindler Company, Philadelphia, PA.J8 p. Desc"be...Ie. w"ere colleclors can ~unr lor rock. and minerai.for a fee, incl"del "'e. in Coliforn,o

McGowen, lorn, 1981, Album 01 rock. and minerals: Rand McNally Corn·pony, Chicago. Delailed d"cu",on 01 55 m,nerol •. lIIu.traled relerencesechon. G.ode. 4·7

Podendorl, 11I0, 19B2 Roch and mineral.: Ch,ldrenl Press, Chicago, 1982.InlroduCl,on 10 Ihe formal,on and ,denr,licot,on 01 a varIety of rock. andm,nerol•. Early elementary grade•.

lenn,,,en, Anthony, 1971. Colorful m,"eral ,denl,lier: Sterling Publi.h,ng.New York. A baSIC introduchon to m,nerology. Can be u.ed to qUICklyident,ly common m,nerol,. Gradel 10 and up

MISCELLANEOUS

Cooper. Elizabeth K., 1970, Science in your Own backyard: Harcourt, 8roce& World, Inc. New York, 192 p Incl"des .ecttons on lossils, ,0,1 androcks, water, otmo.phere o. well 01 flowers, graSl, and snails.

S.mon, Seymour, 1982, How 10 be a space S"lSnt"t ,n your own home: J,8L,pp,ncotT Compony, New York. A collect,on 0124 expe"menh ""ng,nexpen.ive mOleriol•. Grode. 9·12.

S,man, Seymour, 1988, How to be on ocean scienllsl in your own homeJ,B. lipp,ncon Compony, New York. InformaT,on on Ilem. ,uch O. how 10make Ire.h waler Irom <eowoter, lime and tide., making wove. ,n Ihebalhtub, and mak,ng wove, in on oquari"m.

Updegraff, Imlllda, and Updegraff, Rober!, 1980, Eorthq"okes and volcon·oel; Penguin 800ks. New York Examine. Ihe cou.e. and effects 01earthquake, and volconoe,.tncl"de. a leclion of I,mple experimentsand OCh,he•.

Updegraff. Imelda, and Updegraff, Roberr, 1980, R,vers and lake" Pengu,nBookl, New York. Sections on I,mple experiments and ocl,v'tie•. Elemen.tory grades,. Compiled by Mary ff_BdOllr. ~

'" CALIFORNIA GEOLOGY May 1990

Significant Earthquakes1989

Damage 10 bock·faced store In Sonta Cruz from the Of:lober 17, 1989 Lama Prieto quake.Phalo by ~""ard Holden

A llhough the magnitude 7.1 LOIII;LPneta canhqualc that 'lrucl-the

Sama (ru," 1I.lollnlain~of California onOctober 17. [989. made cit'l.en, of theL'mlcd SI:lLC\ parliclllarl~ eunhqualc ....n·'line. then: \lcre actuatt~ ..llghtl~ fcllocr'Ignirlcant carlhquakc~ .... orfd\\idc Junng1989 than the ;l\cragc of the pa" [\It)

u,:cadc\

1;lfl~.II\C \Ignlficum carthqu:tl;c, "crerecorded throughout the \lurid durlllg1'J1l9 Thl\ number.\ ,jx 1cs, 'him the\Igmficanl earthquake' fcpuTted in 1981LSince the J970, \\ hen {'omprchcn'lvcrcconl-kccpll1g ho:gan. about 60 ... ignific:mtcarthqualc\ h:J\c Ix:currcd "at'h year. 011Ihe ;l\a:lgc. A \Ig1llfkill11 carlhquillc i\une Ih1l1 ro:gl\[;,'r, at lca-t 6.5 Rkhll'rmagnnudc or a ..limiter magnlludc lhalC;Ill'C' ca,u:IIIIC' or clJn~ider.tbled~mage

During 1989 a [(jlal of 526 people \.Ierchclie\ed 10 ha\c died \.Iorld\.l Ide fromcarlhquale, Thl' number 1\ 'Iglllfleantl)lo\.ll,'r lhan the :m:r.tge t'igure of IO,{)(X).

Si\ of the world\ ~ignificantcarth­4uale~ during 1989 occurred In IheCniled Sl,lle, or neilrb) .... :ller' In C:lli­fornl:l ,lxl)'I\.lO pcoph.' died III lhe Octo·ber 17 Lorna Pnela earthquale: morelhan 3.500 v.ere IIlJun:d, :lnd propert)damage I~ e~lImaled al 55,6 bilhtlOOther California earthquake, occurred onAugu'l 8 (magnilude 5.3 ncar LO'> Ga1O')and Oil J:lIluar) 19 CmagnllUde 5.2 IIIY.C'1 LO!> Angele,). [0 southern Ala,laa ma!:!nilude 6,9 earthqualc cenleredon,hore III lhe Pacific Ocean wa' felt byrc,idcm, of coa'tal area,. bUI cau,cd nodamagc. On October 7. a magnllude 6.7lremor occurred In lhe Andrcanof 1~land,

III lhe A!cullan l'land~.

The mo,t de,trul'tive eanhquake world·1\ldc during IWI9 .... a' a magnitude 5.3tremor Ih:!l ,hllolthe Tajil region of theSOl leI Union 1)11 J:HlUary 22, lriggeringland, lid.... , Ihat buricd ,everal \lillage~ andlllteJ:1Il e'lIm:lled 27-1 per-on'. The '-CC­ond I11ml dC;ldly ,el,mic e~ent of 1989\\ .. , II lIlaglllludc 5,7 carthqullle In Iranon Augu,t I that I' bclie\ed to haw liJled1l1lea~1 90 people and lllJured 15 \I hen\ illage, \lere 'lruel b) land,lldc, cau!>Cdb) the earthqu:lle.

rhe ~tmnp."llremordnd lhc only"grc;.l1" c;lfIhquale recorded during1989 \la, a magnllude It] c:lrthqu:lkc 1111\1:1) 23 In the Suuth P:tcific ncar the\lJt:quaric hlal1lh aooul midway betwccnAu,trJlia and Ant;lI'\:trc:I A gre:ll earth­qU;lke l~ one wllh ,I magnitude of B.O orl:lrger. Prror to Ihl' Iremor III lhe SuulhI'acilic, JI month, lall'cd wllhoul a grC:lIe;lrlhqual....

U!>lll,!t d:lla rmm 'l'I'llmgraph 'tatltm,throughoulthe \lurid. the U,S. Gelliogi-

cal Sur\ey loe:llC' from 10.000 to 12.000caflhqu:tle~ per )'ear \lhlch h:we magni­tude, of ah\)ul 1,0 to 8,0 IIr morc. Sevcralmillion earlhquakc~ (x'cur cach )'ear. bUIrnll~l arc ~o ~m:l1J or (x'cur in ~och remOle:HC:l' Ihal they lire undetccted b) even lhenUN ,cnSlti\e in~trumcn". Data lin cllrth­quake, prO\ide~ informallOn for U'-C 0)carlh <,<:ienli!>l!> III fcdcrill. 'laIc, and localgmernl1lcnl~. :lnd prrvale Indu!>lr) 10

~luJ) eau'-C~, occurrence, and rcducllllnoflhc hazards of carthqllake~ U.SGf'oloXi,(I! SlIn'f'\ -"nt's Re!etlf('.

(AIIFORNI .... GEOLOGY Mey 19'10

Book ReviewsBooh '",,,,we<! ,n ,h,s .eellon Ore rw! aVo liable lor purchase from OMG.

KCt)'oh gre PQpo,tlor croft on the nv<l' PhotOI courte')' of Eric Peocn, PARe.

The Western Stolel lOO·mlle Run;1 rouled olong Ihe MIddle Fori; Amerlcon R,vet" Runnen negotlotetheGreenwood B"dge ford dUring hIgh woler flow In thOl $Cene

Tllh Ai\lI:IHCAN RIVER N"nh. ,\lId·dle. & South Furl.' \\I,men ..nd cdllcd b)Slcph:m,c Manlkl. 01" \\Iullan. TerryWrl~llI. Em: Peach. Stan PadillJ. and Illlll'f'

198" I'rule'"l Al1lnlcan R,"cr Can)OIhII'ARC}. Il(l~ 9.112. Auhurn. CA 9S6O-J.Sl-l YS. pave.IMc\..

<

PWleC( AmeTlc~n It'\.:r Canyun, I' a nunpwfll. c<locallunal (lr~~nIlall"n h3>("U In Au­burn. California, n("ar the c~n)(lnlanu~ (If theAmerK;,n R,ver II ,"J~ rounded In Ihe 1970­10 pre'enc tile nalUrdl and (uhurdl hcnla~cof the Amcm'an R'H" canyon'

Thl' Amerlcan R"cr,~ an ("a"ly ac<:c",'blc",ldcrnc~\ fUf hiler,. Jtlt:gcr\, hon.cb<l.1.Tide". mUUnlJln b,ler,. antl "hlle "aler

r~fl"r,. The ean)unland, arc nch ,n h"I<I')Jlld '" ddMe

WrlHcn ur I:'HnplkJ.! from many \uuree"lite "'I:I I'Hl~ uf Ihe buuk de,erlbe Ihe unll.JuenJlur.ll re""uree, oflhe rI'...,r"anlllll~ Th"area I' Ih" 'lie ,)( imernalwnal e'''''Ill' - Ihelh" Cup IJur"" Race and Ihe We\l<lrn Siale,11X1-nllk Run - "'hK"h allra,"1 hundred, "f,,~fl"'I"~IlI'and lhou'~nd~of 'pecl~l"r,

The lr:lIh \CCIIl.Hl pro\lde' II1forl11~ll0n abuulIrJII, and Ihelr <'cell"r)". h"h.ncal \lll.",hloltlg":al dl\'Cr'Il). and !""ul,,!,,)

A mlk-h)-mlle gUld" Itl lhe rJpld, andrut:\..) of thl' Ihrl'l' fnr\.., oflh.. r1\l'r I, pr<l'\Cnt<ld III the !>C"ond »Cl-llun Thl' 1!eol,,~y "I,h" ar"a I' l'mpha'l,,,d Thl' N'lflh I·orl. "fIh" A mai,'an R""l'r I) dl''>Cnbe<.J a, J "" lidrl'er "'hid can he run b) rJrl. ,'an"e, orlapl. 111 '" IIlter lind 'pnn!! "" hen ",alcr f1,,,,,e~c<led, 900 cubIC f"cl per "'HlIld Ilcaulyand d:lngcr" pnll11I'Cd In Ih" Mlddll' hnl.The Soulh I'url. "de\.(.'nbcd a, onc uf Ihem'''1 pupular rit'c" IIllhe "e,1 fur raftlllg

SlOrle, and ,ong' ff<)111 N:lIIW AmerKall':lnJ frum Ih" Ilold ru,h cra Jr" prc'Cnl..d InIhe Ihml 'Cl:llOn The fln:ll '1:'1:1 Inn on r""crec"lollY ,laIc' lhatlhe \Cllelm1tm "Ihe r.:,ultuf pa'l Jynallll<: chanlle, of ~·lllnalc. 10M'mphy. geoh'IlY. anJ h'''11C [:lctor" ,oeh a''OIl COI111',,)III0I1 DetaIled Informallun"prOt Ided un Ihe planl and animal life Ihalahuund, In Ihl' are:1

l'hOlUl"raph" mal". and ,I.eldle, arC IrIlcr·,pcr'Cd throughoul Ihe b"ul. Tllc Informa·lion pmvidcd "" Ithln Ihc t'<)II"nc '" III IIdp :Ill10 unl.kT\land :lnd appr"e':'lc Ih.. beauly :U1Jre'lIUH'e, ofthc American Itt""r

'\6 C.4tlfORNI... GEOLOGY

A/o.1EIOCAN lOVER RECREATIONAREA (Map No. I,. By Mimi JCnlrd andDianI' Kra£c, 1911S, Available from Fnend~

of Ihe River. 909 I2lh SI reel. 11207. Sacra­mCnlO. CA 95814. (916) 442-3155. 1\·lap54,00; rn"p and de~eropl"'e leXI un une ,heel.30 melle, x 21 Inehe,. Map ,calc: I Inch =I l1ule

Thl~ Inlerprelive Irall anJ £ulde map W Iher,,'cr and eanyons of Ihe American RiverReeremi()n arca depieh rapid,. river mile"dIrt-road" Iralls. reereallon Mea boundarle,.['Icnle area, and "anous Olher fealUres fur IheNurth Furk and Middle ForI. oflhe AmerieanR,vcr. The area IS m;lIlaged by Ihe CaliforniaDepartmenl of P-Mk~ and Recrealion.

Indian grinding rac~ hales in bedrock. Native ...Americans ground acorns, seed., and nul. 10meal in thell! bedrock morlor>. The preporolionof lood involved mony hour> of persiSlent grind·ing_ which woo only one pho.e 01 the process.

•-•

,MOine Bar, 1858. Miners loilto e~lroClgold w,th pock, .hovel, and wheelbarrow alongside the "hurdy-gurdy," 0 plocer mining dev,ce. This placermln,ng .,Ie,~ on Ihe Middle Fork Americon R,ve.. . .. more book reviews

CALIFORNIA GEOlOGY M01 1990 117

• More Book Reviews

nIl:. .1I1l9 SAN FRANCISCO l:.ARTlI­QUAKl:.. PORTRAITS OFTRAGI:Ill' A:\I>COliRAGl:.. By the ~1:aUof the L,., Anl(f'/nTimt's (pholo edllor Larr) Arm~tron~. le\lcull'l( Cr,ll! Turncr). 19119 lol. An~e1(',

Time_. Time> i\lIrror SqUiIIll:. Lo" An~cl(').

CA 90053 96 p. 59 95. p<tpcrb;\d

Th., bool.. one of loC,'cr,,1 fcccnt booh lileII. 'l'n"C,:., an OUblandmt! Tecon! and ('Onl­mentar) on the human "de urlhe Lurnal'ncla earthquake of Octobcr 17. 1111\9 ,n lh...Santa Crill M.»!ntam,. II con\',,)", the nle,·,age uf the dt"qrllCll"c fon-e: of the carlh­"lllalc and the re'lhence of Ihe wrvl\'orsthruugh Il-l compdJlIlg color phUIOIlr.lI,h,(VI IIh Cal)!It"" and no''';'') :ll1d U brief 'lO­ne> The ,1Orle, and pliolO carllon' :ll'pcarto ht: 1.1ke" from the pagc~ of the I.m,j".e"It'.i Tillll'S.

rOlhe trJlncd eye. wnw of the pholo­~raph, al", tell a ,tory aboullhc Iype of'UltClurl.') and ground condlll0n) lhal cannol.... Ilh,tand a major C'anhquake and Ihe rcla·llon)hlp bC'1 .... een failed ~round and falleO;!bllIldln~' rhotOl!r"ph,. npIlOn). and C'),:a)~.

all b) lhe' .laff of the Los AIl~('f('s T,m('s. IC'IIlhC' \lor) of InC' C'Jrlhqu:akC") df«b

Mo""'9 Induofl'y

TOOt\Y'S TECHNOLOGY fOR THE\IINING ANI> METALLURGICAL IN·nUSTRIES. Papers Presented allhe MMIJIMM JOlnl SymposIum. 1989 In'WUllon of\lIning and Metaltu"!y. oW Purlland Place.LonoJon. WIN 41~R. Englalld 623 p$13500. wflcO\'Cr

A colletll"n ofsc>'cnly papers pre""nlC'd atIi'll' JOlnl Sympo!oium of Ihe M ming and Ma·lerlal. l'nlCc"mg Inslitule of Japan (MMlJ)Illld the In.tltulion of .... , Inln~ and ~klallurgy

(IMMJ makc up this volume. 1'1'11' paper,cO"cr a .... Ide range of actlvilie. _ nllncralcconomlC) and new Icchnology in eAplora·IIl>n. rock engmecnng. h)drornC1allurg). andIhe rccenl dewlopmenl of ne.... malenal. pro­tes"ng III Jap;an The IOPIC) alw rcflecllheInlcre~1 IIllhe developmenl of nc ....' field, ofre<carch and productIOn IIllhe mlnlllg andmeullu,,!K::lllndu,lrlCs,

QUANTITATIVE DYNAMIC STRATIG­RAPHY By T,"lOIhy A Cross. 1990 PrC'n·lice Ihll. PrC'nlice Hall BUIlding. I:'.ngle ....·oooJCMf). NJ 07632. 625 p H:ard cover

Sll1lllgnphy IS Ihe study of layered rods.IReorporal,ng many IOPICS lradillonally con­SIdered lhe domaln~of indiVidual sublh""I'pllne~ wllhln Ihe earth science,. Quaniliallvcdynamic ,trar,graphy i, Ihe appllc3l1on ofmalhemallcal quamitallve procC'dure. II) Iheanaly,,) of geodynamic. qrallgraphlc .•edl­menlol0l:\Ic. and hydrauhc allnbules of ",dl-

menlary baSin). ucallng IhC'm as fealurC'sproduced by Ihe Inlera<:llOn) of dynamiCprocesSoCS ,

1'1'11) book I' lhe prodUCl ora ....ori,)hoponquanl1lau,'e d}namK: sll'al1graph) held InFcbn.llry 1988 The ...·orbhop .....:as sponsoredby Ihe American AS!iOC'I..I\Oft of PcuoleumGcolOl!Isls. Ihe Colorado School of Mines.lhe Gas Re\OC'.rch Instllule. Ihe NatlOn..1Sci­ence Foundallon. the U.S DepUlnlCnlOfEne"!y. and Ihe U,S Geological SUH'C'Y·

Papc::rs wllhln lhe volume summarize andprovIde examplC's of Slale-of-lhe-art ap­proachC's 111 quanhlallvt ~nal)'~lsof scdlmen­lary bUlI1s. Siraligraphic proce~!>C'sofsedimentary ba~lns al all scales - from gco­dynamics. to straugraphlc fill and flUid flo......10 ,edlmenltransporl- arc analyzed In lhlstCXI Thc quanlilativc approach to under­standing Ihese procc)Sts IS accomplishedIhrough computer mooellng which II has Ihepotential of proVIding even more accurateassessment, dCSCrlpllon. and predICtiOn ofscdlmenlary basIR paramcters Inlhe future.

Included arC' p:lpeni OR mettlOds of modeleonSlrUCllon~ gC'od) namlc formallon and evo­IUlion of basll"s; SlratlgraphlC and sedlmenla­lion models; hydrocarbon maturation andsedlmenl dIageneSIs modcls~ dynamiC ocC'anCIrculation and c1lmale modcls~ palcOl!eo­graphic reconslnK:hons USlnll a mass-balanceapproach; rC'solullOll of geoloilK: lime fromlilhooilr:lllllraphy. blOSlrallllraphy. and chem­ICal Slratl!rlIphy~ dala bases and methods fore>""lualing basin modcls; and eompull:r pro­llDms Ihat Slmulale -liedllnl:nl fill and .sedl­menllr.tl'isporl

aua"er!y Journal

GEMS ANI) GI:MOLOGY. thc qU3ncrl)Journal of the Gemological In'IIlUl" ofAmerica. 1660 Sle"'art Street. 1'0. I~ox

2110. Sama Mnnll·a. CA 'J0406 U.S:539.95 per year 14 ;'.ue.); $9J 95. thrccyear,. EI.e.... here $49.00. onc year; SI24.00.three years

The Gcmologll'al InQllute of Amenca(GIA)I' :I nonprofLl educallonal organlzallonfor Ihc JC"'elr) Indu~lr) ThIS }OUrnal SPO"'wrcd by Ihe In)htule fe.. ture. comprehensl''C'arllcles on l!em,lone "jcntlfIC31IOR. ne....gem)IOnes. ne ..... 1n)lrUnlCnt. and IdC'nlifica·tion Icchnl'llK'). ') nlhellcs and 'Imtllam~.

gem locallllc_. JC.... clr) ans. and ,mporl..nlcollectIOnS RC~lIlar fUlures Incilldc currenlne.....s Ilems. gC'm IradC' lab noles. and ab­stra<:b orart,cle~ Inlhe fIeld of 8emo~)

The Spring 1989 ISSIIC' (\·olumc 25. no. I'eonlalns arhCk'~ :about IhC' Slnkanku Llbrar)al lhe GIA. Santa MonK:a. Callforma; IheGUJar KIlh emerald deposll In PaklSlan;Ber)1 gC'm l'Iodule) from Ihe Ibnanal mine.BraZIl; and OpalltC' pla)tlc IInl1.Ltlon opal"L1h Iruc play of col'lf SomC' facts aboUI afla" les_ 7.6 ClOr.Ll hcnlloltc \tone. lhc Slategem ofCahfornla. arc rewaled In thc l::dllo­rial Forum Secllon

Full·color pIHJlugraph.:1' .....cll.L. cwellentarticles glvc th" Journlrl a d"hncll>'c quality

lJI:.LT.\ SLllSlDl:.."'CI:: 1"'\ I:.STIGA1'10.... PrOl\'re" Reptlfl for fl...:al 'ear­19116-19811 1989 SlaleofCahf"rnl~.

I)ep;irlmenlol \\;ucr RewuRc•. PO IJ,,~

qJ28\6. S:6l;r..menlO. CA 9JB6.(1(J()1 ~11 PSJ ~(). f'aper cover \lake dleck\ pa)abk toIhC' Dcp;irlment uf \\aler Resoun·c.

In Jul) 1911!i Ihe Celll11l1 DI.mcl uflhe Statel>Cparlm"nt of \\'~l~'r RC')</ul\'e) beg..n a pro·~.r.Lrn to d"lermmc Ihc cau",. alld r"tl·' uf.uh'ldence In the SaCr.Ll1lenlO-San J"aqumdella at the ,.. "nflucnce of 11'11." Sacrarnemu andS~n loJqu11l rI'er .ptern. The dclta 1\ aCUll1l'lcA net .... lIrk of 1.land. and IntcretlnneCl­mg .I"u~h. 1'1'11. re~lllll on'uf'lc. murc lhan7011.()OU acre. and Inc IudI.', 60 Ie"eeo;! "land.an<l ""cr 7(J(J 11111<" uf ":Iter .... a). '\'11"1 uf the<leila I. r<·cL.lIm<·d I1IM.hbnd th.Lt I' cnherne.Lr .ea I....cl or.L' much a, _'0 fecI helu">ca Ie,cl A nel .....,rk of allout I. IOU rnlle.01 Ie'ee. " nC'ce"ar) ro prol..-cllhe I\land.and Ira.:r. a~all1'1 Ooodll1f

Sedlmenl def'O'lllon m lhe rel!It," uf 11'11'dclla hcj;Jn aboul 175 million )Car-. :.go. In~cncr.L1. <c,Jm,ent accumulauon dunnl! IhC'pa\1 millIOn )C':.r. oceurrC'd durm~ allcrnatee)dC'. of deJlO'>UI,," and crO)Ion Delta f'C'''''be~an 10 (orm aboul 11.000 )C;lr...go durlOl!a !Iobal n-e In -ea lewl O\'C'r lhc IRleT\..-n·mg. centur"". IhC're ....3. an aln""l conl,"II"u,f..rmatlQn and .ubrncr~enceof peat Submer·gencC' uf thC' peal prC'\"Cnled natural dc,'om·f'O'II10n throul;h O~Idallon Tn" lack ofO\Idallon enabled >eg.C'lauOR 10 accumulalcand form a peallhld.nes) of PC'al

Agneullllr..1de'elopmenl )lncC IhC' 1850\ha" .ub-equcnll) o'ld'r.ed rhe organic '011).nu"nl! acr"b,c dccompl}'>ll,on. and rc.ullll1gIR .ubsldence SlOce 1980. 2J delta 1,land,ha"c f100dcd bccau.c man)' of Ihe prOleclinglevee. failcd due 10 un.table organl<: wlh and.ub>tdence nf the l~land). Signifrl':lnt .ub'ld·ence of the "land. cau~e. Increa.cd h)dro­.ralrC pre"ure on the Ic'ee. and comrlbule.to le'ec fallurc

The Centrall)"trict bcl:'an thc I)cll.L Sub­'Idence In\'C.tl~atlon10 revlc ....· dala. conlactOIhcr conccrned agencle•. and oulllne a pro·Ill1lm 10 d"crnllnc \'au-e~ and ralC\ of ,hal·10'" and deep ,uo--Idcnce TheSe' ,Jala .IreImptlllanl for makmg decI)lon) regardmgland man:agement mea.ure. 11'1:'1 cOllld ~IO'"

.ul»ldenccThe fUlurc of the Delta depend. he:,vII) on

Ihe e .. lentlo .... hK:h IC\=s arc mamlalned,and )l.It",del'K'C' "a eonuoJllnll factor ,n IhC'amount and t) PC' of malnlenance reqUiredlinder'landll'il!- thC' prOCC'SloC' of )ul»ltJence"nll,nl .... hen allempl1n~ 10 maml310 IheIC'\'C'C' )·.tem

The 1986-1988 pha<c of the )ub'lden,C'lO'e.tlgallon Included lI1)1alla"on of I.... UeXIcn""UM:ler .lallO.\) Icomp;KlIon 1\'C(Il'dC'r.,.e.labll.hment of a baloChne Globall..... llIon­mg S).tem net"orkto determ,ne IJn<l \urfaceclC".Ltlon. compllallon and e'.Lluatlon ofl>clla !la. field prodllclLon. and a )une) ofl)ella ground "alcr u•.: Thc.c mca)ure\. a.pan 01 ~ long-term program ..... 111 provI,Je

118 CAlIFORNtA GEOLOGY May 1990

.... ....naI VIeW 01 0 pon>on 01 the De/to regtOn.obout Molen I'bIel well of Siockton. Col.forll>O.­The o.bo IS formed by the two ITlOfOr '-ton'll 01tlte Cen/fol ....,. _ the Sacramen.o and the SonJooqIiIn R''''!!n - OS they merge "to. _ ~ond Row th.ough Su<sun Boy ond CorqlllnnSlra,llIllO the Son F.on<.<SCo kry Art,lH;tOll<IvHshove be.n bu'" on the naturol chonnel banh roptolectthe r>e:h ogncultv<ollat>d ol.he Oelro ".lands frOft'l fIood,ng The flood,ng ol.helaw landeleYoI,onl of Ihe ,slands, os seen," .he lo.e·g'O\It>d. iU"'lrolet Ihe dependence 01 'he DelroIslonds on .h.e I...ee syslem ond Ih.e ,,"poetlhO!tubl<dence WO\lk! hoye on the delICate Iond·wole. tnlerlo<. PItolO by J C DoIWg US~and ,,_ Resources 5e""'Ce

....................................................................................................................

•

STOR'I\\AT£R Dl:.il:.'T10l\ fa'!' [)Q,ln·I~C. "'aler Qualll). and CSO \Ianafl.'tMnlIi) Pl:ll.'r Stahle: and Ben Crona' 1990 Prell­lice Ihll. l',enllce HJlll~ulldlntt. I.nflt.... oodCliff,. NJ 07632 3Jll p. hard c~r

In Ihe la'i 25 )'car, 'Iorm"alcr mana!;cmcn'till' becumc un I(llpl'rlanl pafl of walel re­'\lURe, eRlllnC,'rlnl! anJ nlanagclllcnt In the1'>110.. Ihree conccrn~ emerged - ,Iurm",llcrquall1~. the development of rnmhcnHlllclilmodel, Itl "muble ~lOrm"alcr.and the U'>Cof Uclcnllon 'IOr.I!!C DclcnllOl1 'lor.ljlC plan­"mil and Ik~ll!n In\olvC') til dl.'tcnllon of(Iood "iller and 1211hc trealment oflhc qual­n) \.( '1('1\'",,,,:11«\ When pl"OfK'rl) applied,,\0..m",31(r maul!rmcnl can rc-dl,l<;c lilt ad­'tr~ ImJIXb of :ICl."clcr.llcd )Iorm... atcr lun­off from lImanllcd l:ands b) sJO'Io Inll lheruooff and b) U'fnO\ ,nl! polhmlnl' fromurban rul'Mlff

Tt\l~ '(lllalll(' prC'Stnb the 1M«) ..nd pr3(­

IKC of U~lnJ! lklcnllon !>lonp- In ~tl...m"llIC'mlln1l~mcnl It I~ d1\ Mkd Into four ~nlOll~I) JlC" of ~tonJ!c fXlln K"i. flcoto K~ulltlOtl.

c"lmlllln~ !>lon~c \olumc'. and )torm""lcrqUllhl) cnh""Cemenl The bool. "11' .. rmenfor the prat'tKlRj! cnJ!tnter. \lorm"'1I1e, m<lnagel. or I) I ll':\lboot< III urban \torm"'"te,cn~1ncennJ! ~

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Yuba Clty·Moryt",ne ptoducl'O<HOIlwmpllOll <eglOn. 1988 (_)__ 5RIJ6 MU'lllhd,ng and mudflows of Wnghtwood, Son 5ernordu.o CO\Inty. 1979__ 51/155 510bll<zahon ollondll!del eHedlol yo"o..s chemICols on Ihe Ioboratory

sheor strenglh of on ewponllY.~,19B.__ 5RI56 M,n.ralland clali,IKOltOn 01 portlond c.menl concr.'e·grode agg.egale

Socrom.nto.Four..ld 1988 (n.w)__ SRI 58 M,n.rallat>d dOIS,lic:ahon oggrego•• ft'I<I"nol"n Itl. Fresno

produc:hon·COllwmphon r"9lOn. 1988 (new)__ SRI59 Mln.ralland CIa."fN:atI01l aggregal. matenok 1ft .... Palm Spnngs

ptoduc:'IOn-COnIUmpllOn 'eg,OIl 1989(_)__ SRI6J s..rfoc. ond groundwat•• ft'l<lnoge......, 1ft wrioc. mlMd-land.edomahon.

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Intercsted 10 the gcological. geophysical.and 'iClsmological aspcc15 of lhe Califor­ma conllnenlal maf];10 Each Ofl~~~n ma.ps 1lo111 conlaln foor platesII) gcxIIO@:). (2) carlhquale ~ter!>andsciccled faull-plane M.llulJon~. 0) gravityand m3gnetic anomallcs O\"Crprlfltcd onscrecned geologic hackground. alld(4) offshorc oil and ga~ wells. trdelilfle,.and data M.lUrce Data are pnmarily 11l

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Bullcl1n 207. Geology of the C01lifornlaContlllCnlal Margm EXPU\NATION 01'TIlE CALIFORNIA CONTINENTALMARGIN GEOLOGIC MAP SERIES. byMM.·hac1 P. Kennedy. H. Gary Gr«nc.and Samuel I!. Clarlc a compalllon pub­IU::lIl1l1l. conlaln- an c",planallon of 10­

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Sc\~r.all.:lnds of remQte.loCn 109 dcvtccsIlocre u.\oCd to 1O\~\tl!!atc and ~ather d:Jta3houl lhe geology of the Cahfor0l3 Conti­nental margm for thiS map SCrlCS Thc:!.cda.la lOc1ude high resolutlOfl reflectionprofilc... g:llhered \l,llh echo sounder.sparker. :Jnd mcchanical pUlslOg S)'.\IClm.and IOlermcdllltc· to dcep-pcnetrJtiooprofile... g3lhered wl1h sparler. lIlr gun.and ll.:Jlcr gun s)'!>tcm~.

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Map No.6. Geology oflkt' Norlh­Centr.al California Contl~ntal MargIn.Arc~ 6 (of se'o~n ar~). 4 ~celS foldedIn ~n\'~Jope SIS 00

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