Text
'TTACHMENTSA.'Resume-RichardB.Hubbard.B.C.D.E'.Biography-EliSilver.Biography-ClarenceA.Hall,~Jr.Resume-StephanAlanGraham.CurriculumVitae-WilliamR.Dickinson.G.H.K."TheSanGregorio-HosgriFaultZone:AnOverview,"-'liSilver."Evidencefor115KilometersofRightSlipontheSan'Gregorio-HosgriFaultTrend,"S.A.GrahamandW.R.Dickinson."SanSimeon-HosgriFaultSystem,CoastalCalifornia:EconomicandEnvironmentalimplications,"C.A.Hall,.Jr."OriginandDevelopmentoftheLompoc-S'antaMariaPull-ApartBasinanditsRelationtothe'SanSimeon-HosgriStrike-SlipFault,WesternCalifornia,"C.A.Hall,Jr."MarineGeologyandTectonicHistoryoftheCentralCaliforniaContinentalMargin,"E.A.Silver,D.S.McCulloch,andJ.R.Curry."ApplicationofLinearStatisticalModelsofEarthquakeMagnitudeVersusFaultLengthinEstimatingMaximumExpectableEarthquakes,"RobertK.Mark.L.USGSOpenFileReport77-614,"RegressionAnalysisofEarthquakeMagnitudeandSurfaceFaultLengthUsingthe1970DataofBonillaandBuchanan,"R.K.MarkandM.G.Bonilla.M.N.O.Biography-JamesN.Brune.CurriculumVitae-J.EnriqueLuco,CurriculumVitae-MihailoD.Trifunac.P.R."Reviewofthe'SeismicEvaluationforPostulated7.5MHosgriEarthquake,Units1and2,DiabloCanyonSite,'"J.EnriqueLuco."CommentsonSeismicDesignLevelsforDiabloCanyonSiteinCalifornia,"M.D.Trifunac.USGSOpenFileReport78-509,"EstimationofGroundMotionParameters,"D.M.Boore,A.A.Oliver,R.A.Page,andW.B.Joyner.
IgJ.T dqql~hq-~~ATTACHEZARichardB.Hubbard366CaliforniaAvenueSuite7PaloAlto,CA94306(415)329-0474EXPERIENCE9/76-PresentPartner-MHBTechnicalAssociates,PaloAlto,California.'ounderanmanagingpartnerotecnicaconsutingirm.Specialists,in:independentenergyassessmentsforgovernmentagencies,particularytechnicalandeconomicevaluationofnuclearpowerfacilities.Con-sultantinthis.capacitytoIllinoisAttorneyGeneral;SuffolkCounty,NewYork;Schweinfurt,Germany;GovernorofColorado;andSwedishEnergyCommission.AlsoprovidedstudiesandtestimonyforvariouspublicinterestgroupsincludingCenterforLawInThePublicInterest,LosAngeles;PublicLawUtilityGroup,BatonRouge,Louisiana;andUnionofConcernedScientists,Cambridge,"Massachusetts.ProvidedtestimonytoU.S.Senate/HouseJointCommitteeonAtomicEnergy,U.S.HouseCommitteeonInteriorandInsularAffairs,CaliforniaAssembly,LandUse,andEnergyCommittee,AdvisoryCommitteeonReactorSafe-guards,andAtomicSafetyandLicensingBoard.PerformedcomprehensiveriskanalysisoftheaccidentprobabilitiesandconsequencesattheBarsebackNuclearPlantfortheSwedishEnergyCommissionandedited,aswellascontributedto,theUnionofConcernedScientist'stechnicalreviewoftheNRC'sReactorSafetyStudy(WASH-1400).2/76-9/76Consultant,Pro'ectSurvival,PaloAlto,California.VolunteerworkonNucearSareguarsInitiativecampaignsxnCaiornia,Oregon,Washington,Arizona,andColorado.Numerouspresentations-onnuclearpowerandalternativeenergyoptionstocivic,government,andcollegegroups.Alsoresourcepersonforpublicservicepresentationsonradioandtelevision.5/75-1/76%fanger-QualitAssuranceSectionNuclearEnergyControlandnstrumentationDeoartment,GeneraEectrz.cComoanv,SanJose,axorna.a.eporttoteDepartmenteneraManager.Deveopand~pqh'yyd,yd,hd,dq'ph'hthatproductsproducedbytheDepartmentmeetqualityrequirementsasdefinedinNRCregulation10CFR50,AppendixB,ASMEBoilerandPressureVesselCode,customercontracts,andGECorporatepoliciesandprocedures.Productareasincluderadiationsensors,reactor ttvesselinternals,fuelhandlingandservicingtools,nuclearplantcontxolandprotectioninstrumentationsystems,andnuclearsteamsupplyandBalanceofPlantcontxolroompanels.Responsibileforapproximately45exemptpersonnel,22non-exemptpexsonnel,and129hourlypersonnelwithanexpensebudgetofnearly4milliondollarsandandequipmentinvestmentbudgetofapproxi-mately1.2milliondollars.11/71-5/75/Manaer-ualitAssuranceSubsection,ManufacturingSectionoftomicowerauzomentDeaxtment,eneraectrz.cComDan,'anJose,Caizoxnia.ReporttotheManagerorManuacturing.Sameunctzonaanproduct-responsiblitiesasinEngagement><1,exceptataloweroxganizational=reportlevel.DevelopedaqualitysystemwhichreceivedNRCcertificationin1975.Thesystemwasalsosuc-cessfullysurveyedforASME"N"and"NPT"symbolauthorizationin1972and1975,plusASME"U"and".S"symbolauthorizationsin1975.Responsibleforfrom23to39exemptpersonnel,7to14non-exemptpersonnel,and53to97hourlypersonnel.,3/70-11/71Manaer-AplicationEnineerinSubsection,NuclearInstrumentationeartment,enexar.ectrxcComoan,SanJose,Caiornia.Respon-seeortepostoraertecnnxcaznteracewxtarcdetectengineersandpowerplantownerstodefineandscheduletheinstrumentationandcontrolsystemsfortheNuclearSteamSupplyandBalance.ofPlantportionofnuclearpowergeneratingstations.Responsibilitiesincludedpreparationoftheplantinstrumentlistwithapproximatelocation,reviewofinterfacedrawingstodefinefunctionaldesignrequirements,andreleaseoffunctionalrequirementsfordetailedequipmentdesigns.Personnelsupervisedincluded17engineersand5non-exemptpersonnel.12/69-3/70Chairman-EuivmentRoomTaskForce,NuclearInstrumentationDepart-ment,GeneraEectrx,cComan,banose,axorna.a.esponsz.eoraspeciatasforcereportingtotneDepartmentGeneralManagertodefinemethodstoimprovethequalityandreducetheinstallationtimeandcost"ofnuclearpowerplantcontrolrooms.Studyresultedintheconceptionofafactory-fabricatedcontxolroomconsistingofsignalconditioningandoperatoxcontrolpanelsmountedonmodularfloorsectionswhicharecompletelyassembledinthefactoryandthoroughlytestedforproperoperationofinteractingdevices.Personnelsupervisedinclude10exemptpersonne'l.I'2/65-12/69Manaer-ProosalEnineerinSubsection,NuclearInstrumentationeaxtment,GeneraEectrxcComoany,SanJose,Cax.ornza.Respon-seeorteappicationoinstxumentatxonsystemsornuclearpowerreactorsduringtheproposalandpxe-order"period.,Respon-siblefortechnicalreviewofbidspecifications,preparationof technicalbidclarificationsandexceptions,definitionofmateriallistforcostestimating,andthe"assold"reviewofcontxactspriortoturnovertoApplicationEngineering.Personnelsupervisedvariedfrom2to9engineers.8/64-12/65SalesEnineer,NuclearElectronicsBusinessSectionofAtomicoweruivmentOeoartment,eneraEectrx.coman,anaose,Caiornia.Responsieforteireview,contractnegotiation,yd~C*1powerplants,testreactors,andradiationhotcells.Alsorespon-sibleforindustrialsalesofradiationsensingsystemsformeasure-mentofchemicalproperties,level,anddensity.10/61-8/64AlicationEnineer,LowVoltaeSwitchearDepartment,GeneralEectricCpm@an,Piaexa,Pennsvania.Responsieortheapp>cationanddesignoadvanceiodeansiliconcontrolledrectifierconstantvoltageDCpowersystemsandvariablevoltagedcpowersystemsforindustrialapplications.Designed,followedmanufacturingand"personalllytestedinadvancedSCRpowersupplyforproductintroductionattheIronandSteelShow.ProjectEngineerforadcpowersystemforanaluminumpotlinesoldtoAnacondabeginningatthe161XVswitchyardandencompassingalltheequipmentto.,convertthepowerto700voltsdcat160,000amperes.9/60-10/61GERotationalTzaininP~totamFour3-monthassignmentsontheGERotationalTrainingProgramforcollegetechnicalgraduatesasfollows:a.InstallationandServiceEn.-Detroit,Michigan.Installationanstartuptestingotteworsargestautomatedhotstripsteelmill.b.Tester-IndustrControl-Roanoke,Virinia.Factory,testingocontropanesorcontroostee,paper,'ulp,andutilitymillsandpowerplants.c.Enineer-LihtMilitaElectronics-JohnsonCit,NewYork.eszgnogrounsupportequipmentortestingteautopx,otsontheF-105.d.'alesEn~ineer-Morrison,Illinois.Saleofappliancecontrolsincuxngrangetimersanrezrxgeratorcoldcontrols.A3 EDUCATIONBachelorofScienceElectricalEngineering,UniversityofArizona,1960.MasterofBusinessAdministration,UniversityofSantaClara,1969.PROFESSTONALAFFILIATIONRegisteredQualityEngineer,LicenseNo.QU805,StateofCalifornia.MemberofSubcommittee8oftheNuclear-PowerEngineeringCommitteeoftheIEEEPowerEngineeringSocietyresponsibleforthepreparationandxevisionofthefollowing4nationalQ.A.Standards:a~IEEE498(ANSI.N45.2.16),SupplementaryRequirementsfortheCalibrationandControlofMeasuringandTestEquipmentusedintheconstructionandmaintenanceofNuclearPowerGeneratingStations.b.IEEE336(ANSIN45.2.4),Installation,Inspection,andTestingRequirementsforInstrumentationandElectricEquipmentduringtheconstructionofNuclearPowerGeneratingStations.c.IEEEP467(ANSIN45.2.14),QualityAssuranceProgramRequire-mentsfortheDesignandManufactureofClassIEInstrumen-tationandElectricEquipmentforNuclearPowerGeneratingStations.d.IEEEDraft,RequirementsfortheProcurementandStorageofClassIEEquipmentReplacementParts.PERSONALDATABirthDate:7/08/37Married;threechildrenHealth:Excellent"PUBLICATIONSANDTESTIMONY1.SwedishReactorSafeStud:BarsebackRiskAssessment,1KBTecnicalAssociates,January17PuishebySweshDepart-mentofIndustryasDocumentDSI1978:1).2.TheRisksofNuclearPowerReactors:AReviewoftheNRCReactorSaetStuvMASH-w,Kena,eta,eateyR.B.Hubardan.C.ManoroxUnionofConcernedScientists,August1977.A
~a~~3.TestimonyofR.B.HubbardtoAdvisoryCommitteeonReactorgafeguards,August.12,1977,Washington,DC,entitled,RiskUncertaintDuetoDeficienciesinDiabloCanonQualitssuranceProramanFar.uretomementCurrentNRCPractices.TestimonyR.B.HubbardtoUnitedStatesHouseofRepresentatives,SubcommitteeonEnergyandtheEnvironment,June30,1977,Washington,DC,entitled,EffectivenessofNRCReulationsModificationstoDiabloCanonNucearUnx.ts.5.TestimonyofK.B.HubbardandG.C.Minor,JudicialHearingsRegardingGrafenrheinfeldNuclearPlant,March16617,1977,Wurzburg,Germany.6.TestimonyofR.B.HubbardandG.C.MinorbeforeCaliforniaStateSenateCommitteeonPublicUtilities,Transit,andEnergy,Sacramento,California,March23,1976.~7.TestimonyofR.B.Hubbard,D.G.Bridenbaugh,andG.C.MinortotheCaliforniaStateAssemblyCommitteeonResources,LandUse,andEnergy,Sacramento,California,March8,1976.8.TestimonyofR.B.Hubbard,D.G.Bridenbaugh,andG.C.Minor.beforetheUnitedStatesCongress,JointCommitteeonAtomicEnergy,February18;1976,Washington,DC.(PublishedbyUnionofConcernedScientists,Cambridge,Massachusetts.)ExcerptsfromtestimonypublishedinuoteWithoutComment,Chemtech,May,1976.9.ualitvAssurance:ProvidinIt,ProvinIt,R.B.Hubbard,Power,Hay,19710.In-CoreSstemProvidesContinuousFluxMapofReactorCores,R.B.HubardanC.E.Foreman,Power,iVovemer,17.A5.
I~0~'IIIc AUG1B$78ATTACHMENTBBiographicalData,EliSilverAssociateProfessor,EarthSciencesUniversityofCalifornia,SantaCruzBorn-June3,1942B.A.-Geology,UniversityofCalifornia,Berkeley,1964Ph.D.-Oceanography,ScrippsInstitutionofOceanography,1969Post-GraduateResearchOceanographer,ScrippsInstitutionof'Oceanography,1969-1970Geologist,U.S.GeologicalSurvey,1970-1974AssistantProfessor,EarthSciences,UniversityofCalifornia,SantaCruz,1974-75AssociateProfessor,EarthSciences,UniversityofCalifornia,SantaCruz,1975-presentChiefscientistand/orcruiseleaderonnumerouscruisesofScrippsInstitutionofOceanographyandtheU.S.GeologicalSurveyFellow:GeologicalSocietyofAmericaMember:AmericanGeophysicalUnion,SocietyofExplorationGeophysicists,SeismologicalSocietyofAmerica,AAASSelectedPublicationsMoore,G.W.,andSilver,E.A.,1968,Geologyoft:heKlamathRiverDelta,California:U.S.Geol.SurveyProf.Paper600-C,p.C144-C148.Moore,G.N.,andSilver,E.A.,1968,GolddistributionontheseafloorofftheKlamathMountains,California:U.S.Geol.SurveyCirc.605,9p.Silver,E.A.,1969,LateCenozoicunderthrustingofthecontinentalmarginofnorthernmostCalifornia:'Science,-v.166,p.1265-1266.Silver,E.A.,1971,TransitionaltectonicsandLateCenozoicstructureofthecontinentalmarginoffnorthernmostCalifornia:Geol.Soc.AmericaBull.,v.82,no.1,p.1-22.
Silver,E.A.,1971,TectonicsoftheMendocinoTripleJunction:Geol.Soc.AmericaBull.,v.82,p.2965-2978.Silver,E.A.,Curray,J.R.,andCooper,A.K.,1971,TectonicdevelopmentofthecontinentalmarginoffcentralCalif.:Geological'SocietyofSacramento,AnnualFieldTripGuidebook,p.1-10.Silver,E.A.,1971,Smallplatetectonicsofthenorth-easternPacific:Geol.Soc.AmericaBull.,v.82,p.3491-3496.Silver,E.A.,andothers,1972,USGS-IDOELeg4,Venezuelan.borderland:Geotimes,v.17,p.19-21.Silver,E.A.,1972,Subductionzones:Noterelevanttopresent-dayproblemsofwastedisposal:Letter,Nature,v.239,p.330-331.Silver,E.A.,1972,PleistocenetectonicaccretionofthecontinentalslopeoffNashington:Mar.Geol.,v13Ip239249Jackson,E.D.,Silver,E.A.,andDalrymple,G.B.,1972,Hawaiian-EmporerchainanditsrelationtoCenozoicCircumpacifictectonics:Geol.Soc.AmericaBull.,v.83,p.601-618.Dalrymple,G~B.,Silver,E.A.,andJackson,E.D.,1973,OriginoftheHawaiianIslands:AmericanScientist,v61Ino.3,p.294-308~Silver,E.A.,vonHeune,R.,Crouch,J.K.,1974,TectonicsignificanceoftheKodiak-Bowieseamount,chain,NortheasternPacific:Geology,v.2,p.147-150.Silver,E.A.,1974,Geometricalprinciplesofplatetec-tonics:inSanJoaquinGeological,Soc.ShortCourse,GeologicalInterpretationsfromglobaltectonicswithapplicationsforCalif.geologyandpetroleumexploration,N.R.Dickinson,ed.,p.1-1to1-3.Silver,E.A.,1974,Basindevelopmentalongtranslationalcontinentalmargins:inSanJoaquinGeologicalSoc.ShortCourse,GeologicalinterpretationsfromglobaltectonicswithapplicationsforCalif.geologyandpetroleumexploration,N.R.Dickinson,ed.,p.6-1to6-5.B-2 Silver,E.A.,1974,EvolutionoftheSanAndreasfaultsystem:inSanJoaquinGeologicalSoc.ShortCourse,GeologicalinterpretationsfromglobaltectonicswithapplicationsforCalif.geologyandpetroleumexploration,W.R.Dickinson,ed.,p.12-1to12-5.Silver,E.A,1974,Detailednear-bottomgeophysicalprofileacrossthecontinentalslopeoffnorthernCalifornia:U.S.Geol.SurveyJour.ofResearch,v.2,p.563-567.Silver,E.A.,Case,J.E.,andMacGillavry,H.J.,1975,GeophysicalstudyoftheVenezuelanborderland:Geol.Soc.AmericaBull.,v.86,p.213-226.Silver,E.A.,1975,Collisioneventsinorogenesis(abs):13thPacificScienceCongress,Vancouver,Canada.Silver,E.A.,1975,Collisioneventsinorogenesis:EOS,v.56,p.1066.Silver,E.A.andMoore,J.C.,1976,AgeophysicalstudyoftheMoluccaSeacollisionzone,Indonesia(abstract):EOS,Trans.AGU,v.57,p.1003.Silver,E.A.',1977.TheSulaspurenigma(abstract):Geol.Soc.Amer.Abs.withPrograms,v.9,p.1175-1176.Silver,E.A.,1977,AretheSanGregorioandHosgrifaultzonesasinglefaul'tsystem'P(Abstract):Geol.Soc.Amer.Abs.withprograms,v.9,p.500.Silver,-E.A.,1978,Geophysicalstudiesandtectonicdevelop-mentofthecontinentalmarginoffthewesternUnitedStates,34'o48N:inGeol.Soc.AmericaMemoir,Smith,R.B.andEaton,G.P.,eds.,(inpress).Silver,E.A.andMoore,J.C.,1978,TheMoluccaSeacollisionzone,Indonesia:Jour.Geophys.Res.,v.83.Blake,M.C.,Campbell,R.H.,Dibblee,T.H.,Howell,D.G.,Nilsen,T.H.,Normark,N.R.,Vedder,J.G.,andSilver,E.A.,1978,Neogenebasinformationandhydro-carbonaccumulationinrelationtotheplatetectonicevolutionoftheSanAndreasfaultsystem,California-Amer.Assoc.PetroleumGeol.Bull.,March1978.Silver,E.A.,1978,TheSanGregorio-Hosgrifaultzone:Anoverview:Calif.Div.MinesandGeol.SpecialPub.137.Silver,E.A.,McCulloch,D.S.,andCurray,J.R.,1978,MarinegeologyandtectonichistoryofthecentralCaliforniacontinentalmargin:SubmittedtoAAPG.Bull.
0~'4~"Y,+E%
ATTACHMENTCBZOGRAPBYCLARENCEA.EKLJR.SocialSecurityNumber:569-34-9229Address:2427S.ArmacostAvenue820LosAngeles,CaZifoznia90025Home2'elephone:(223)473-3061Bvainess2'eZephone:(223)825-2020DateofBirth:Born:,xi~Le:Eaum~tzm:January5,1930-CitizenoftheUnitedStatesLosAngeZes,CaHforniaPropessoz'fGeologpB.S.,StanfordUniversity,2952lAS.,Sta.fordUniversity,2953Pn.D.,S~-"ordUniversity,2956Pa"tciployment:RomdValleyPmgstenNine,Bishop,CaHfornia,Geologist,2952U.S.C~ologicalSuey(Orgon),Geologist,1953UnivesityofOregon,1'nstrvtorinGeology,2954-55Z~ZeOil~nRefiningCcnvany,Geologist,2955StanfordUniversity,lnst~mtorinGeoZogp,2956Suv..er~.,pKoyment,V.S.GeologicalSurvey,Geologist,2972-78Vniversi='wofCalifornia,LosAngeles,AssistantPz'ofessoztoProfessor,2966toPresent;Chairman,Depa~~.entofGeology,9-2-74to22-31-76,ActingChairman,DepartmentofGeophysicsandSpacePhysics8-2-76to12-31-76,Chairman,DepaztmentofEazthandSpaceSciences1-2-77to8-32-78ScholarlySocieties:ZeZZ~GeologicaZSocietyofAmericaPaleontologicalSocietyofAmerica-EditorJournalofPaZeontology,1971-72NalacoZogicaZSocietyofCaZifozniaZonorsandAwards:ZulbrightResearchScholaz;2taly,2963-64and2970-72invitedLectvwer,PoHshAcademyofScience,2964 C.A.Halls~~~sogi.,~,s2~3e6.7e8.9.195819581959-1959195919591960I'GeologyandpaleontologyofthePleasantonarea,AlamedaandcontraCostaCounties,Calif.:Univ.Calif.Pub-Geol.Sci.,v.Q4,no.1,p.1-90,pls.l-l2,2.figs;5maps.GastropodGenusCeratostomaGeol.Soc.Asser.Bull.,69,.12,I.RR~.S7.(ABII'IIICI'ITheGastopod,Genus'Ceratostoma:Jour.Paleontolo~,v.33,no.3,p.428-430,3pls.1959.PigeonpointFormationofLateCretaceousage,SanElateoCo.Caliz.:Amer.Assoc.Patrol.GeologistsBull.,v.5,no.12,p.2855-2859,1959.EDisplacedIO.oceneVG3.luscanProvincesalongthe'anAndreasault.PacificPetroleumGeologistNewsletter,Amer.Assoc.Petro3..Geol.,v.13,no.-3,p.4.(ABSTRACT)Displaced1ioceneMolluscanProvincesalongtheSanAndreasF"ult,Calif.,GeologicalSocietyofAmericar--s+(+.srtnsgt,ssss.>nssssssym.x.,v.jO,no.12,pt.,p.Displaceh'.!ioceneMolluscanProvincesAlongtheSan9deasFault,,Calif.:Univ.Cali.Pub.Geol.Soc.~v.3LI,no;6,p.-281-308.CeratosiG.aHerrmannsen,1%6(ClassGastropoda);propose"'ditiontotheOfficiallistofGenericHams.A.Fi.(S)1088:Bull,.Zoo3..Homencl.,v.18,pt.5,p.336,1961.GeologcYapofCalifornia,SanFranciscoSheet,Calif.Div.ofI4ines,1961(Contributor).3.0.196212.1962196411.1962DisplacedMioceneYiolluscanProvincesalongtheSanAndreasFaultinGuidebook,Geologyof'arrizoplainsandSanAndreasFault,1962:pac.Sec.Amer.Assoc.Petro3..Geol.,p.20,1962.-'IDisplacedViocenemolluscanprovincesalongtheSanAndreasFault,Calif'.:Amer.Assoc.Petro3..Geol.,v.06,no.10,p.1952-3.960,1962.EvolutionoftheechinoidgenusAstrodapsis:Univ.Calif.Pub.Geol.Sci.,v.40,no.2,p.$7-180,1962.AreaArc"lepton;ramnica,anewlateTertiary'eecypoErom.zeSanLuisObi"poPegion,Calif'.:Jour.paleo.,v.3U,no.3.,p.87-88,3.96>i.C-2
'5.ag.I'yusca~,g~0gcI6<~~cg+51I23>pe3-4'lag5'n'as4x~jescaggQ3sv'Chas~e~yaSo~e~~9y964.gQXQAConsxt~ol~gyn.o~ene~><>>1<pe(XS>~~gn~t'64~go<a~.Zo+~g64g~gh~.3~~ana>~g~,d.at'e$46~.es~gute+.~annGeney3-9o'apto~aSg>s<y96-MeT~.Qfas'ej.ttos.fr~a>t,.3>>sggo6e~~~CtheOf2>>~.enusneue@SICy6.~togoyips.enc~'hknopefeTgQGof~'"Sc~.>~gG-'g~on~~u~+g.Geo'oi<eT,ox+s,Cafoss>ftheCoasy,opu>-.gch>no0~~sgo~an~es~a+ye'gageO~ho'gn+ha~)ongSo(~qgQQns5Sgss~-.b>ngg3->",'e's~ocengcI$6~oceg>9egaV>~you>~(>>~paanegea-haeoon~he-23-peShepdacha,.fzo>Z2Bo:x9~othe0>o~fgh.eGof.Soc-20-"-..-at,>onGo>-Sec~an<~ggz~a><anzojccZeo3-.fomang'gegesoSQ82eeCga>9~of.~of.tuSethemp,~~51a9oquadeT~t,o4~~St~aC5qo~g~yea+y967~OCM>GeohhC~Y~og5-9622-5.a.<x>>th.0>isQ63>.owng6't<guhsgee~'ot~cga$>.eSanSoc~yQ,e~',~.sghGeolQe>~geboooCo'g..2'Pa~Gu0~~so.Sect>.~yesops~'-9Qu>.gyeyan.jgj.ncgC+4~Co~~'usfo'e>S.~ct,use(ir>th-0>>sgpuca'yg6'722'9',Sag,rfense.Guthe.a.T)eCa-~fGoyo~.fga>tozy.shoct~onog>3-9Co-Geo>.t,h~Qe"25-Copseofag<<'ona~ont,>on>>Q.3.t,g3~0Qo~pe<an,SuQuQyQaCSec0'026~.tih<a~s>~yo6<o.2>n 27-197028..197329.19733O-1973-~~~e1~TheObis~Formationandasociat~volcanicrockin.theGentle.CaliforniaCoastRange~-K-Ar'agesandbiochronologicsignif'icance.Geol.Soc.Americaab'stractswithprograms,CordilleranSection,66thAnnualmeeting,v-2,no.2,(srithD.L.Turnerand,R.C.Surdam).GeologyoftheArroyoGrandequadrangle,SanLuisObispoCo.,Californa:C"lif-Div.ofNinesand.GeologyNapSheet24.~~GeologicmapoftheMorroBaySouthandportSanLuisquadrangles,SanLuisObispoCo.,California.U.S.'eological.Survey1G'11MapSeries.POligoceneandMioceneFelsicVolcanism,NestCentra3.CaliforniaCoastRanges,Amer,.Geophys.UnionIieeting,Fall,1973(abstract}(~rith8.G.Ernst).197'974197032.33197<3)+.35-'975Shellgro;i-~hinTivelastultorum(Mawr,1823)andca11mechioneTL'nnaeue,1(55Iaiva1via):Annua1perxoc'city,latitudinaldifferencesanddiminution~withage,(rrith>T.A.DollaseandC.E.Corbato).'Palaeo~eography,Palaeoclimatalogy..Paleoecology.v3.5>p.33>>61.GologyandPetrologyofheCambriaFelsiteaHetr03.i=ocenFormation'tTestCentralCalif.CoastRanges.Geol.Soc.Amer.Bu13,v.U5>p523532'Nith7T.G.Ernst).Geo"og'I:aooftheCambriaRegion,.SanLu-sODispoCounty,California.U.S.,GeologicalSurvey,MiscellaneousF'eldStudiesMap599in1974.\Latiud,nalvariationinshellgrosrthpatternsofbivalve'mo3~uscs:implicationsandproblems:He@castle.Symposium,Vol.;1974.LatitudinalvariationinshellgrowthpatternsofbivalvemoI3.uses:implicationsandproblems.p.163-173InGrowthRhythmsandthehistoryoftheEarth'rotation,G.D.Rosenbergand.S.K.Runcorneds.John3/ileyandSons.36.1975FeldspathicGeodesHearBlackMountain,WesternSanLuisObispoCounty,California,Geol.Soc.Amer.,abstracts~"ithprograms,CordilleranSection,73.stAnnualI,"ecting,March,1975.(WithlT.G.Ernst)(ABSRACTe)~37-1975GeologicmapoftheCayucos-SanLui"Obisporepion.U.S-Geol.Surv.Misc.FieldStudiesMap,M;686C-4~~
i38.197539.197540.197541.197642.1976INPRESSINPRE-PARATIONFeIdsphicgeodesnearBlackMo&tain,westernLuisObispoCounty,California:Amer.Min.,V.60,'.1105-1112.(withM.G.Ernst)SanSimeon-Hosgrifaultsystem,coastalCalifornia:economicand,environmentaIimpIications.U.S.GeologicalSurveyOpenFileRept.,75-533,12manuscriptpages.SanSimeon-Hosgrifaultsystem,'oastalCalifornia:economicandenvironmentaIimpIications.Science,v.190,'p.1291-1293.GeologicMapoftheSanSimeon-PiedrasBlancasRegion,SanLuisObispoCounty,California:U.S.GeologicaISurveyMisc.FieIdStudiesMap,MF784,scaleofI:24,000.OriginanddevelopmentoftheLompoc-SantaHariapull-apartBasinanditsrelationtotheSanSimeon-HosgriFault,California:GeologicalSocietyofAmerica(ABSTRACT)GeologicMapoftheSantaHariaValleyRegion,Santa"BarbaraCounty,California:U.S.GeologicalSurvey.Misc.FieldStudiesMap,scaleofI:24,000.Cerozoicbas'ins,CentraICaIifornia,(Probably'aliforniaDivisionofHineswiII,publishGSASy-posiumpapers(seeabstract4'42forgeneraldi'scussion).
r~~{<~q~
~~p~ATTACHMENTDStephanAlanGraham2136GreenwoodDr.SanCarlos,CA94070GeneralBorn4/25/50,Evansville,Indianahhrried5/27/72,wife-Pmela,1childU.S.citizen,militarystatus-lH,foreignlanguage-GermanEducationA.B.IndianaUniversity.1972M.S.StanfordUniversity1974Eh.D.StanfordUnivesity1976Geology,withHonorsGeologyIGeologySpecialization:Sedimentarygeology,inparticularsedimentarytectonicsThesis:addleTertiarypaleogeographyandstructuraldevelopmentoftheSalinianblock,California;Eh.D.committee:W.R.Dickinson(advisor),J.C.Ingle,Jr.,B.M.Page51973:7.1976:ProfessionalEcperiencel.1968,1970:Subsurfacemapping,FritzOperatingCo.,Ft.Branch,Ind.,(summers)2.1970:X-raydiffractometertechnician,IndianaUniv.,Bloomington,Ind.,(part-time)3.1971-1972:ConsultinggeologistforPeninsulaExplorationCo.,CorpusChristi,Texas,(part-time)4.1972:AssociateInstructor,IndianaUniversityGeologicFieldStation,Cardwell,hantana,(summer)Researchassistant,StanfordUniversity,Stanford,Ca.,(summer'6.1973:Instructor,Stanf'ordGeologicalSurvey,Bridgeport,Ca.,(summer)ResearchGeologist,ExxonProductionResearchCo.,Houston,Texas8.1,976-ExplorationGeologist,ChevronUSAInc.,SanFrancisco,CAAwards,1.2~3~5~6.7~8.Assistantships,andFellowshipsEarthSciencesFreshmanScholarship,IndianaUniversity,1968ArthurR.hertzDistinguishedScholarship,IndianaUniversity,1968-1972IndianaUniversityGeologicFieldStationtuitionaward,1969StandardOilof'exasundergraduategeologyaward,1969,1970Beststudentpaper,RockyMtn.Section,Geol.Soc.America,1971Seniorfacultyscholarshipaward,3adianaUniversity,1972%hiBetaKappa,1972NationalScienceFoundationGraduateFellowship,1972-1975
~~2ProfessionalSocietiesGeologica1SocietyofAmericaSigmaXiSocietyoZconomicPaleontologistsandMineralogistsPublicationsGraham,S.A.,1971,OccurrenceofmiddleCambrianislandsinsouthwest&ntana:Geol.Soc,AmericaAbs.withPrograms,RockyMtn.Section,383-384.Graham,S.A.,andSuttner,L.J.,1974,OccurrenceofmiddleCambrianislandsinsouthwestleant~a:%hebhuntainGeologist,v.11,71-84.Graham,S.A.,1974,RemanantmagnetizationofmoderntidalflatsedimentsfromSanFranciscoBay,California:Geology,v.2,223-226.Graham,S.A.,Dickinson,W.R.,andIngersoll,R.V.>1975,Himalayan-BengalmodelforflyschdispersalintheAppalachian-Ouachitasystem:Geol.Soc.AmericaBu11.,v.86,43,273-286.Dickinson,W.R.,andGraham,S.A.,1975,Sedimentaryenvironments,depositionalsystemsandstratigraphiccyclesincurrentconceptsofdepositicnalsystemswithapplicationsforpetroleumgeology;W.R.Dickinson,editor:SanJo~uinGeologicalSocietyShortCourse,Bakersfield,1-10.Graham,S.A.,1975,TertiarysedimentarytectonicsofthecentralSa1inianblockofCalifornia:Geol.Soc.AmericaAbstractswithprograms>v.7,no.7,1089.Graham,S.A.,1976,TertiarysedimentarytectonicsofthecentralSalinianblockofCalifornia:Eh.D.Dissertation,StanfordUniversity,Stanford,California,510p.Graham,S.A.,1976,TertiarystratigraphyanddepositionalenvironmentsnearIndiansRanch,1hntereyCounty,California:TheNeogeneSymposium,Pac.Sect.,Soc,Econ.P01eontologistsand5!ineralogists,125-136.Grahmn,S.A.,1976,TertiarystratigraphyanddepositionalenvironmentsnearIndiansRanch,bbntereyCounty,Ca1ifornia:Amer.Assoc.ofMtroleumGeologistsBull.(abs.),2181-2182.Graham,S.A.,1976,SanGregorioFaultasamajorright-slipfaultoftheSanAndreasFaultsystem:Geol.Soc.AmericaAbstractswithPrograms,v.8,no.6,890.Graham,S.A.,Ingersoll,R.V.,andDickinson,W.R.,1976,CommonprovenanceforlithicgrainsinCarbon'erousfromOuachitat~ountainsandBlackWarriorBasin:JournalofSedimentaryPetrology,v.46,620-632Dickinson,W.R.,Graham,S.A.,andIngersoll,R.V.,andJordanT.Z.,1976pApplicationofplatetectonicstopetroleumgeologyalongthePacificmarginofNorthAmerica:Aner.Assoc.PetroleumGeologistsBull.(abs),2179.Graham,S.A.,and.Dickinson,W.R.,1977,Apparentoffsetsofonl'andgeologicfeaturesacrosstheSanGregorio-Hosgrifaulttrend:Geol.Soc.AmericaAbstractswithPrograms,v.9,no.4,424.Graham,S.A.,andDickinson,W.R.,1978,Apparentoffsetsofon1andgeologicfeaturesacrosstheSanGregorio-Hosgrifaulttrend:Science,v.199,179-181.=D-2 Graham,S.A.,andDickinson,V.R.,1978,ApparentoffsetsofonlandgeologicfeaturesacrosstheSanGregorio-Hosgrifaulttrend:Calif.Div.YiinesandGeologySpecialReport(inpress).Graham,S.A.,1978,RoleoftheSalinianblockintheevolutionoftheSanAndreasfaultsystem:Amer.Assoc.PetroleumGeologistsBull.,v.62,gll(inpress).bTelephone(415)894-0308(office8:00AM-4:00PM.)(415)595-2036(home)
~~
CurriculumVitae-Wm.R.DickinsonBorn:Nashville,Tennessee,Oct.26,l931Degrees(allStanfordUniversity):B.S.,Pet.Engr.1952M.S.,Geology1956Ph.D.,Geology1958USAF,1952-1954FacultyPositions(allStanfordUniv.):ActingAssistantProfessorAssistantProfessorAssociateProfessorProfessor1958-601960-631963-681968-PresentGuggenheimFellow1965ArticlesinScience,Nature,'eol.Soc.AmericaBull.,Jour.Geophys.Research,Am.JourSci.,Am.Assoc.PetroleumGeologistsBull.,Jour.Sediment.Petrology,Sediment.Geology,Tectonophysics,EarthandPlanetarySci.Lettrs.,Rev.GeophysicsandSpacePhysics,Can.Jour.EarthSci.MemberofGeol.Soc.America(Fellow),Am.Assoc.PetroleumGeologists,Am.Geophys.Union,Soc.Econ.PaleontologistsandHineralogists,Nat.Assoc.GeologyTeachers,Am.Assoc.Adv.Sci.Chairman,CordilleranSec.,Geol.Soc.America(1974-1975);President,PeninsulaGeol.Soc.(1977-1978);Councillor,Geol.Soc.America(1977-1980).A.I.LevorsenMemorialAward,Pac.Sec.,Am.Assoc.PetroleumGeologists(1978-1979).MaorConferenceParticiation1966-speaker,SymposiumonCircum-PacificOrogenesis,PacificScienceCongress,Tokyo,Japan.1967-co-convener,JointUSGS-Stanford'ConferenceonGeologicProblemsofSanAndreasFaultSystem,StanfordUniversity.1967-speaker,IUGG-IAVConferenceonAndesites,OregonInstituteforVolcanology.1969-speaker,AndesiteSymposium,VolcanicStudiesGroup,GeologicalSocietyofLondon.1969-convener,GSAPenroseConferenceonPlateTectonicsandOrogenicBelts,Asilomar,California.1970-co-organizer,SymposiumonCretaceousGeologyofCentralCalifornia,GSACordilleranSectionMeeting,Hayward,California,.
~(~~~~1971-co-organizerandspeaker,NASSymposiumonPlateTectonics,Washington,D.C.1971-keynotespeaker,SymposiumonPetrologyandGeochemistryofIslandArcsinRelationtoTectonicEnvironment,PacificScienceCongress,Canberra,Australia.1971-organizerandkeynotespeaker,SymposiumonPlateTectonicsinGeologicHistory,NationalGSAmeeting,Washington,D.C.1972-speaker,CarnegieInstituteConferenceonPlateTectonicsandthe'volutionofContinents,Airlie,Virginia.1972-speaker,JointNSP-WisconsinConferenceonAncientandModernGeosynclinalSedimentation,Madison,Wisconsin.1973-convener,SEPMResearchSymposiumonTectonicsandSedimentation,AAPG-SEPMNat.Mtg,,Anaheim,California.1974-speaker,GACSymposiumonVolcanicGeologyandMineralizationintheCanadianCordillera,Vancouver,Canada.1974-convenorandspeaker,SanJoaquinGeologicalSocietyShortCourseonPlateTectonicsandPetroleumGeology,Bakersfield,California.1975-convenorandspeaker,SanJoaquinGeologicalSocietyShortCourseo'DepositionalSystemsandPetroleumGeology,Bakersfield,California.1975-Speaker,SymposiumonCircum-PacificMagmatism,Metamorphism,andSedimentation,PacificScienceCongress,Vancouver,Canada.1976-invitedspeaker,EwingSymposiumofLamont-DohertyGeologicalObservatory,Harriman,NewYork.1976-convenorandspeaker,SymposiumonPre-TertiaryofBlueMountainsProvince,GSACordilleranSectionMeeting,Pullman,Washington.1976-instructor,AAPGShortCourseonPlateTectonicsandHydrocarbonAccumulation,AAPGNationalMeeting,NewOrleans,Louisiana.1976-speaker,SEGShortCourseonPlateTectonicsandSedimentaryBasins,SEGNationalMeeting,Houston,Texas.1977-speaker,SymposiumonPaleozoicPaleogeographyofthePacificCoast,PacificSectionSEPMMeeting,Bakersfield,California1977-speaker,AAPGShortCourseonContinentalMargins,AAPGNationalMeeting,Washington,D.C.1978-keynotespeaker,InternationalGeodynamicsConferenceontheWesternPacific,Tokyo,Japan.E-2 Is1l1978-speaker,SymposiumonMesozoicPaleogeographyofthePacificCoast,PacificSectionAAPGMeeting,Sacramento,California.E-3 ListofPublicationsinGeoloicalSciencebWilliamR.DickinsonWRD,WRD,1958,MesozoicmarineclasticrocksofvolcanicderivationinsouthwesternGrantCounty,Oregon(abs}:Geol.Soc.AmericaBull.,v.69,p.1554.1959,StructuralrelationshipsofChurchCreekandWillowCreekFaults,SantaLuciaRange,California(abs.):Geol.Soc.AmericaBull.,v.70,p.1715.1960,GeologyoftheIzeearea,GrantCounty,Oregon(abs):Dissert.Abs.,v.20,no.11(1958Ph.D).1960,PetrologyofJurassicmarinetuffs,centralOregon(abs)':Geol.Soc.AmericaBull.,v.71,p.2056.1961,JurassicandesiticprovincealongthePacificmarginofNorthAmerica(abs):Geol.Soc.AmericaAbs.for1961,p.19.1962,BrecciatedserpentineextrusiononTableMountainincentralCaliforniaCoastRanges(abs).:Geol.Soc.AmericaAbs.for1962,p.34.1962,Marinesedimentationofclasticvolcanicstrata(abs):AmericanAssoc.PetroleumGeologistsBull.,v.46,p.263.1962,HetasomaticquartzkeratophyreincentralOregon:Am.Jour.Sci.,v.260,p.249-266.1962,PetrologyanddiagenesisofJurassicandesiticstrataincentralOregon:Am.Jour.Sci.,v.260,p.481-500.1962,PetrogeneticsignificanceofgeosynclinalandesiticvolcanismalongthePacificmarginofNorthAmerica:Geol.Soc.AmericaBull.,v.73,p.1241-1256.1963,TertiarystratigraphicsequenceoftheHancockRancharea,MontereyandKingsCounties,California:Pac.Sec.Am.Assoc.PetroleumGeologists-Soc.Econ.PaleontologistsandHineralogistsAnn.FieldTripGuidebooktoGeologyofSalinasValleyandSanAndreasFault,p.47-53.WRDandL.W.Vigrass,1964,Pre-CenozoichistoryofSuplee-Izeedistrict,Oregon:.implicationsforgeosynclinaltheory:Geol.Soc.AmericaBull.v.75,p.1037-1044.WRD,1965,FoldedthrustcontactbetweenFranciscanrocksandPanacheGroupintheDiabloRangeofcentralCalifornia(abs):Geol.Soc.AmericaSpecialPaper82,p.248-249.WRDandL.W.Vigrass,1965,MesozoichistoryofSuplee-Izeedistrict,centralOregon(abs):Geol.Soc.AmericaSpecialPaper82,p.325.WRDandJ.G.Smith,1965,GeologicalrelationsoftheKoroimavuaGroupinnorthwestVitiLevu:FijiGeol..SurveyDept.Note121,4p.WRDandJ.G.Smith,1964,GeologicalroadlogfromNandiInternationalAirporttotheNausoriHighlands:FijiGeol.SurveyDept.Note122,6p.E-4
~~~Publications,WilliamR.DickinsonPagetwoSmith,J.G.andWRD,1965,AgeologicalreconnaissanceofthesouthernYa'sawaIslands:FijiGeol.SurveyDept.Note125,6p.WRDandL.W.Vigrass,1965,GeologyoftheSuplee-Xzeearea,Crook,Grant,andHarneyCounties,Oregon:Ore.Dept.GeologyandMineralIndustriesBull.No.58,109p.WRD,1965,TertiarystratigraphyoftheChurchCreekarea,'ontereyCounty,California:Calif.Div.MinesandGeologySpecialRpt.86,p.25-44.WRD,1966,ProblemsofstratigraphicnomenclatureinFiji(South-WestPacificGeologicalSurveyConferencePaper):FijiGeol.Survey'G.S.Note9/66,10p.WRD,1966,TableMountainserpentiniteextrusioninCaliforniaCoastRanges:Geol.Soc.AmericaBull.,v.77,p.451-472.WRD,1966,StructuralrelationshipsofSanAndreasfaultsystem,CholameValleyandCastleMountainRange,California:Geol.Soc.AmericaBull.,v.77,p.707-726.WRD,1966,PetrographyofspecimensfromtheMamanuthaGroup:FijiGeol.SurveyDept.G.S.Note20/66,5p.WRDandD.R.Lowe,1966,Stratigraphicrelationsofphosphate-andgypsum-bearingupperMiocenestrata,upperSespeCreek,VenturaCounty,California:Am.Assoc.PetroleumGeologistsBull.,v.50,p.2464-2470.WRD,1967,Circum-Pacificandesitetypes(abs):Am.Geophys.Un.Trans.,v.48,p.253.WRDandTrevorHatherton,1967,AndesiticvolcanismandseismicityaroundthePacific:Science,v.157,p.801-803.WRD,1967,TectonicdevelopmentofFiji:Tectonophysics,v.4,p.543-553.WRD,1967,ProblemsMstratigraphicnomenclatureinFiji(abs):N.Z.Jour.GeologyandGeophysics,v.10,p.1181-1182.WRD,1968,Circum-Pacificandesitetypes:Jour.Geophys.Res.,v.73,p.2261-2270.WRDandArthurGrantz(eds),1968,ProceedingsofconferenceongeologicproblemsofSanAndreasfaultsystem:StanfordUniv.Pub.Geol.Sci.,v.11,375p.WRD,1968,SedimentationofvolcaniclasticstrataofthePlioceneKoroimavuaGroupinnorthwestVitiLevu,Fiji:Am.Jour.Sci.v.266,p.440-453.IHatherton,TrevorandWRD,1968,AndesiticvolcanismandseismicityinNewZealand:Jour.Geophys.Res.,v.?3,p.4615-4619.WRD,M.J.Rickard,F.X.Coulson,J.G.Smith,andR.L.Lawrence,1968,LateCaenozoicshoshoniticlavasinnorthwesternVitiLevu,Fiji:Nature,v.219,p.148.E-5 Publicons,WilliamR.Dicki~>>;onPaget)treeWRD,1968,ComparisonofCalifornia'sFranciscanassemblageandGreatValleysequencetoNewZealand'saxialandmarginalfacies(abs):Geol.Soc.AmericaSpecialPaper115,p.322.WRD,1968,Singatokadunesands,VitiLevu,Fiji:Sed.Geology,v.2,p.115-124.WRD,1968,Blendofteachingandresearch(letter):Science,v.162,p.1221.Noble,D.C.,WRD,andClark,M.M.,1969,CollapsecalderaintheLittleWalkerarea,MonoCounty,California(abs):Geol.Soc.AmericaSpecialPaper121,p.536-537.Rich,E.I.,R.W.Ojakangas,WRD,andWinSwe,1969,SandstonepetrologyofGreatValleysequence,SacramentoValley,California(abs):Geol.Soc.AmericaSpecialPaper121,p.550.WRD,R.W.Ojakangas,andR.J.Stewart,1969,BurialmetamorphismofthelateMesozoic'reatValleysequence,CacheCreek,California:Geol.Soc.AmericaBull.,v.80,p.519-525.WRD,1969,Evolutionofcalc-alkalinerocksinthegeosynclinalsystemof.CaliforniaandOregon,p.151-156inMcBirney,A.R.(ed),Proceedingsofandesit'econference:Ore.Dept.GeologyandMineralIndustriesBull.65,193p.InPac.Sec.Soc.Econ.PaleontologistsandMineralogists,1969,FieldTripGuidebook(WRD,ed):GeologicsettingofupperMiocenegypsumandphosphoritedeposits,upperSespeCreekandPineMountain,Ventura'ounty,California,91p.:(a)(b)(c)(d)WRD(p.1-24),GeologicproblemsinthemountainsbetweenVenturaandCuyama.WRD(p.49-55),MiocenestratigraphicsequenceonupperSespeCreekandPineMountain.WRD(p.63),quaternaryterracegravelsandcolluviumonsouthsideofPineMountain.WRD(p.68-77),Roadlog,Ojai.toOzena.Hatherton,TrevorandWRD,1969,TherelationshipbetweenandesiticvolcanismandseismicityinIndonesia,theLesserAntilles,andother,i.slandarcs:Jour.Geophys.Res.,v.74,p.5301-5310.Swe,WinandWRD,1970,SedimentationandthrustingoflateMesozoicrocksintheCoastRangesnearClearLake,California:Geol.'oc.AmericaBull.,v.81,p.165-188.WRD,1970,TectonicsettingandsedimentarypetrologyoftheGreatValleySequence(abs):Geol.Soc.AmericaAbs.withProgs.;v.2,p.86-87.Gilbert,W.G.andWRD,1970,Stratigraphicvariationsinsandstonepetrology,GreatValleySequence,centralCaliforniacoast:Geol.Soc.AmericaBull.,v.81,p.949-954.E-6
~~Publi.ons,Wflliamk.DickinsonPagefourlWRDandPage,B.M.,1970,CentralCaliforniaCoastRanges:GuidetoFieldTripNo.1,CordilleranSec.,Geol.Soc.AmericaAnn.Mtg.1970,25p.WRD,1970,Thenewglobaltectonics(report:2ndPenroseConference):Geotimes,v.15,no.4,p.18-22.WRDl1970,Globaltectonics(report:2ndPenroseConference):Science,v.168,p.1250-1259.WRD,1970,Interpretingdetritalmodesofgraywackeandarkose:Jour.Sed.Petrology,v.40,p.695-707.1970,Relationsofandesiticvolcanicchainsandgraniticbatholithbeltstothedeepstructuresoforogenicarcs:Geol.Soc.LondonProc.,no.1662,p.27-30.1970,Geologyandgeologistsinregionalplanning(abs):Geol.Soc.AmericaAbs.withProgs.,v.2,p.738-739.WRD,1970,GeologyfortheMasses:Jour.Geol.Education,v.18,p.194-197.1970970,Relationsofandesxtes,granites,andderivativesandstonestoarc-trenchtectonics:Rev.Geophys.andSpacePhys.,v.8,p.813-862;WRD,1971,DetritalmodesofNewZealand"graywackes:Sed.Geology,v.5,p.37-56.1971,Platetectonics(developmentsduring1970):Geotimes,v.16,p.21.1971,Platetectonicmodelsofgeosynclines:EarthandPlanet.Sci.Lettrs.,v.10,p.,165-1?4.1971,Clasticsedimentarysequencesdepositedinshelf,slope,andtroughsettingsbetweenmagmaticarcsandassociatedtrenches:Pac.Geology,v.3,p.15-30.WRD19?9?1,Platetectonicmodelsfororogenyatcontinentalmargins:Nature,v.232,p.41-42.WRD,1971,Complementarity(letter):Science,v.173,p.1191-1192.WRD,1971,Ecologicalquestionnaire(letter):NaturalHistory,v.80,no.2,p.101.WRD1971R971,Reconstruct@onofpastarc-trenchsystemsfrompetrotectonicassemblagesinislandarcs(abs):12thPac.Sci.Congr.Proc.,v.1,p.445.WRD,1971,Platetectonicsingeologichistory:Science,v.174,p.107-113.WRD,1971,Evidenceforplatetectonicregimesinthepast:Geol.Soc.AmericaAbs.withProg.,v.3,p.544.WRDandW.C.Luth,1971,Amodelforplatetectonicevolutionofmantlelayers:Science,v.174,p.400-404.E-7 Publicana,WilliamR.Dickinr~nnPagefiveWRD,D.S.CowanandR.A.Schweickert,1972,Testofnewglobaltectonics(discussion):-Am.Assoc.PetroleumGeologistsBull.,v.56,p.375-384.WRD,1972,TheEarthSciences(secondedition),A.N.Strahler(review):Am.Geophys.Un.Trans.(EOS),v.53,p.258-260.Wright,R.M.andWRD,1972,ProvenanceofEocenevolcanicsandstonesineasternJamaica;apreliminarynote:Carib.Jour.Sci.,v.12,p.107-113.WRD,1972,Platetectonicssymposium(preface):Am.Jour.Sci.,v.272,p.549-550.WRD,1972,Evidenceforplate-tectonicregimesintherockrecord:Am.Jour.Sci.,v.272,p.551-576.WRD,1972,DissectederosionsurfacesinnorthwestVitiLevu,Fiji:Zeitschr.f.Geomorph.N.F.,v;16,p.252-267.Hedge,C.E.,Samoa:WRDandE.I.Valleyv.83,Z.E.Peterman,andWRD,1972,PetrogenesisoflavasfromWesternGeol.Soc.AmericaBull.,v.83,p.2709-2714.Rich,1972,PetrologicintervalsandpetrofaciesintheGreatsequence,SacramentoValley,California:Geol.Soc.AmericaBull.,p.3007-3024.Mader,G.G.,E.A.Danehy,J.C.Cummings,andWRD,1972,LanduserestrictionsalongtheSanAndreasfaultinPortolaValley,California,p.845-858inSherif,M.A.andR.C.Bostrom(eds),ProceedingsoftheInternationalConferenceonMicrozonationfoxSaferConstruction,Seattle,Wash.,987p.WRD,1973,Tettonicaazolleecatenemontuose,art.10,p.190-'200inEnciclopediadellascienzaedellatecnica73:Edizioniscientificheetechniche,Mondadori,Milano,Italy.WRD,1973,Widthsofmodernarc-trenchgapsproportionaltopastdurationofigneousactivityinassociatedmagmaticarcs:Jour.Geophys.Res.,v.78,p.3376-3389.WRD,1973,Reconstructionofpastarc-trenchsystemsfrompetrotectonicassemblagesintheislandarcsofthewesternPacific,p.569-601inColeman,P.J.'ed),ThewesternPacific;islandarcs,marginalseas,geochemistry:Univ.WesternAustraliaPxess,Perth,601p.WRD,1974,Reviewofarcvolcanism(abs):Geol.Assoc.CanadaCordilleranSec.ProgrammeandAbstracts,p.9-10.InWRD(ed),1974,Geologicinterpretationsfromglobaltectonicswithapplica-tionsforCaliforniageologyandpetroleumexploration:SanJoaquinGeologicalSocietyShortCourse,Bakersfield,75p.(a)WRD(p.2-1to2-5),Geologicimplicationsofplatetectonics.(b)WRD(p.9-1to9-6),Platetectonicsandsedimentarybasins.(c)WRD(p.15-1to15-4),Platetectonicsandmigrationofpetroleum.E-8 Publicas,WilliamR.DickinsonPagesixNoble,D.C.,D.B.Slemmons,M.K.Korringa,WRD,YehyaAl-Rawi,andE.H.McKee,1974,EurekaValleyTuff,east-centralCaliforniaandadjacentNevada:Geology,v.2,p.139-142.WRD,1974,Sedimentationwithinandbesideancientandmodernmagmaticarcs,p.230-239inDott,R.H.,Jr.,andR.H.Shaver(eds),Modernandancientgeosynclinalsedimentation:Soc.Econ.PaleontologistsandMineralogistsSpecialPub.No.19,380p.Baldwin,.Brewster,P.C.Coney,"andWRD,1974,DilemmaofaCretaceoustimescaleandratesofsea-floorspreading:Geology,v.2,p.267-270.WRD,1974,Subductionandoilmigration:Geology,v.2,p.421-424.WRD,1974,Platetectonicsandsedimentation,inDickinson,W.R.(ed),Tectonicsandsedimentation:Soc.Econ.PaleontologistsandMineralogistsSpecialPub.No.22,p.1-27.WRD,1974,Islandarcs;Japananditsenvirons(review):Jour.Geologyv.82,p.529.WRD,1975,Potash-depth(K-h)relationsincontinentalmarginandintraoceanicmagmaticarcs:Geology,v.3,p.53-56.InWRD(ed),1975,Currentconceptsofdepositionalsystemswithapplicationsforpetroleumgeology:SanJoaquinGeologicalSocietyShortCourse,Bakersfield,105p.(a)(b)(c)(d)WRDandS.A.Graham(p.O-lto0-10),Sedimentaryenvironments,depositionalsystems,andstratigraphiccycles.WRD(p.1-1,to1-16),Fluvialsedimentsofstreamvalleysandalluvialfans.WRD(p.5-1to5-8),Deltaicdepositsandcyclothems.WRD(p.12-1to12-4),Hydrocarbonoccurrencesinrelationtodepositionalsystems.Graham,S.A.,WRD,andIngersoll,R.V.,1975,Himalayan-BengalmodelforflyschdispersalinAppalachian-Ouachitasystem:Geol.Soc.AmericaBull.,v.86,p.273-286.WRD,1975,Problemsofpre-TertiarytectoniccorrelationsacrossthePacificNorthwest(abs):Geol.Soc.AmericaAbs.withProgs.,v.7,p.604.WRD,1975,Geologyandoil(review):Science,v.189,p.133-134.WRD,1975,Time-transgressivetectoniccontactsborderingsubductioncomplexes(abs):Geol.Soc.AmericaAbs.withProgs.,v.7,p.1052.Snyder,W.S.,WRD,andM.L.Silberman,1975,Tectonicimplicationsofspace-timepatternsofCenozoicmagmatisminthewesternUnitedStates(abs):Geol.Soc.AmericaAbs.withProgs.,v.7,p.1279.E-9 44~Publicns,WilliamR.DickinsonPagesevenWRD,1975,SedimentarybasinsdevelopedduringevolutionofMesozoic-Cenozoicarc-trenchsysteminwesternNorthAmerica(abs):-13thPacificSci.Congr.Abs.,p.397-398.NWRDandW.S.Snyder,1975,Geometryoftriplejunctionsandsubductedlitho-sphererelatedtoSanAndreastransformactivity(abs):Am.Geophys.Un.Trans.(EOS),v.56,p.1066.WRD,K.P.Helmold,andJ.A.Stein,1976,PaleocurrenttrendsandpetrologicvariationsinMesozoicstratanearSouthForkofJohnDayRiver,centralOregon(abs):Geol.Soc.AmericaAbs.withProgs.,v.8,p.368-369.WRD,1976,SedimentarybasinsdevelopedduringevolutionofMesozoic-Cenozoicarc-trenchsysteminwesternNorthAmerica:Can.Jour.EarthSci.,v.13,p.1268-1287.Snyder,,W.S.,WRD,andSilberman,M.L.,1976,Tectonicimplicationsofspace-timepatterns.ofCenozoicmagmatisminthewesternUnitedStates:EarthPlanet.Sci.Lettrs.,v.32,p.91-106.Graham,S.A.,R.V.Ingersoll,andWRD,1976,CommonprovenanceforlithicgrainsinCarboniferoussandstonesfromOuachita-MountainsandBlackWarriorBasin:Jour.Sed.Petrology,v.46,p.620-632.WRD,1976,Platetectonicsandhydrocarbonaccumulation:Am.Assoc.PetroleumGeologistsContinuingEducationCourseNoteSer.No.1,61p.Graham,S.A.andWRD,1976,SanGregoriofaultasamajorright-slipfaultoftheSanAndreasfaultsystem(abs):Geol.Soc.AmericaAbs.withProgs.,v.8,p.890.Ingle,J.C.,Jr.,S.A.Graham,,andWRD,1976,Evidenceandimplicationsofworld-widelatePaleogeneclimaticandeustaticevents(abs):Geol.Soc.AmericaAbs.withProgs.,v.8,p.934-935.WRD,1976,Thewaytheearthworks;anintroductiontothenewglobalgeologyanditsrevolutionarydevelopment(review):Jour.Geology,v.84,p.502.Casey,T.A.L.andWRD,1976,SedimentaryserpentiniteoftheMioceneBigBlue.Formationnear,CantuaCreek,California(abs):Am.Assoc.PetroleumGeologistsBull.,v.60,p.2177.WRD,S.A.Graham,R.V.Ingersoll,andT.E.Jordan,1976,ApplicationsofplatetectonicstopetroleumgeologyalongthePacificmarginofNorthAmerica(abs):Am.Assoc.PetroleumGeologistsBull.,v.60,p.2179.Casey,T.A.L.andWRD,1976,SedimentaryserpentiniteoftheMioceneBigBlueFormationnearCantuaCreek,California,inFritsche,A.E.H.TerBest,Jr.,andW.W.Wornardt(eds),.TheNeogeneSymposium:Pac.Sec.Soc.Econ.PaleontologistsandMineralogistsAnn.Mtg.,p.65-74.WRD,1977,Fossilfuelsandcontinentaldrift:BasterfieldLec.Ser.No.19,Univ.Regina,Saskatchewan,16p.
Publfcons,WilliamR.DickinsonPagee5ghtGraham,S.A.andWRD,1977,Apparentoffsetsofon-landgeologicfeaturesacrosstheSanGregorio-Hosgrifaulttrend(abs):Geol.Soc.AmericaAbs.withFrogs.,v.9,p.424.Ingersoll,R.V.,E.I.Rich,andWRD,1977,GreatValleySequence,SacramentoValley:CordilleranSec.Geol.Soc.AmericaFieldTripGuide,73p.WRD,1977,PaleozoicplatetectonicsandtheevolutionoftheCordillerancontinentalmargin,inStewart,J.H.,C.H.Stevens,andA.E.Fritsche(eds),PaleozoicpaleogeographyofthewesternUnitedStates:PacificSec.Soc.Econ.PaleontologistsandMineralogistsPacificCoastPaleo-geographySymp.1,p.137-156.WRDandD.R.Seely,1977,Forearcstratigraphyandstructure:9thAnn.OffshoreTechnologyConf.Paper2889,Houston,Tex.,p.101-106.D.R.SeelyandWRD,1977,Structureandstratigraphyofforearcregions:Am.'Assoc.PetroleumGeologistsContinuingEducationCourseNoteSeriesNo.5,p.Cl-C23.WRDandD.R.Seely,1977,Stratigraphyandstructureofcompressionalcontinentalmargins(abs):Am.Assoc.PetroleumGeologistsBull.,v.61,p.781.WRD,1977,Tectono-stratigraphicevolutionofsubduction-controlledsedimentaryassemblages,inTalwani,ManikandW.C.PitmanIII(eds),Islandarcs,deepseatrenches,andback-arcbasins:Am.Geophys.Un.MauriceEwingSer.1,p.33-40.WRD,1977,Subductionzones:EarthScienceRev.,v.13,p.7071Packer,D.R.,>TRD,andK.M.Nichols,1977,MemorialtoMarjorieK.Korringa,1943-1974:Geol,Soc.AmericaMemorials,3p.WRD,1977,SubductiontectonicsinJapan:Am.Geophys.Un.Trans.(EOS),v.58,p.948-952.WRD'ndW.S.Snyder,1977,InferredplatetectonicsettingofclassicLaramideorogeny(abs):Geol.Soc.AmericaAbs.withProgs.,v.9,p.950.Graham,S.A.andWRD,1978,Evidencefor115kilometersofrightslipontheSanGregorio-Hosgrifaulttrend:Science,v.199,p.179-181.Howard,A.D.andWRD,1978,Volcanicenvironments,chap.9inHoward,A.D.andIrwinRemson(eds.),Geologyinenvironmentalplanning:McGraw-Hill,N.Y.,p.246-274.WRDandT.P.Thayer,1978,PaleogeographicandpaleotectonicimplicationsofMesozoicstratigraphyandstructureintheJohnDayinlierofcentralOregon,inHowell,D.G.andK.A.McDougall(eds),MesozoicpaleogeographyofthewesternUnitedStates:PacificSec.Soc.Econ.PaleontologistsandMineralogistsPacificCoastPaleogeographySymposium2,p.147-162.
4I'l 1~~Is'~Xnpress,tobeHosgriFaultZE.A.SilvereW.Mines&Geology,ublishedin"SanGregory-.io-California,"editedbyNewmark,Calif.Div.ofSpecialReport137.TheSanGregorio-HoseriFaultZone:AnQverviewEliA.SilverEarthSciencesBoardUniversityofCaliforniaSantaCruz,CA95064TheSanGregorio-HosgrifaultzoneispartofthelargerSanAndreasfaultsysteminCali.fornia.thatformsthemajorlocusofshearduetomovementbetweenthePacificandNorth'Americanplates.AnenormousamountofefforthasbeenandispresentlybeingdevotedtostudyoftheSanAndreasfau1.titelf,andinrecentyearsoffsethistory,se'ismici',increaseddramatically(seedetailedquantitativeknowledgeofandpresent-day'ovementhasforexampleKovachandNur,1973;Crowell,1975;DickinsonandGrntz,1968).Theextentofourknowledgeofotherfaultsoft:heSanAndreassystemismuchlesscomplete,dueinparttothelowerfrequencyofgreatearthquakesandsmalleroffsetonsubsidiaryfaults(andthrefore,perhap,lesserinterestinthesefaults)./'Anotl>erreasonmaybethelocationofsomeofthesubsidiaryfaults.TheSanGregorio-HoserifaultzoneislocatedalongthecoastlinesouthofSanFranciscoforalengthofnearly400km,andmuchofitliesjustoffshorewhereitisdifficulttostudy.Majoroutstandin.,problemsofthisfaultzoneincludethedet:ailsoffaultlocation,continuitybetweentheSanGregorioandHosgrif'auldsegments,offsethistoryoneachsegment,evidenceforHo1ocenemovement:s,andsei.i'oicity,These 1~~~e4Iproblemshave'mportancebothfortheirtectonicimplicationsandtheirbearingonanalysisofseismichazard.forcoastaldeveLopmentandpower-plantsiting.ThepapersinthisvolumewerepresentedaspartofasymposiumontheSanGregorio-HnsgrifaultzoneattheCordilleransectionmeetingoftheGeologicalSocietyofAmrica,inSacramentoinApril,1977.Notallofthosepapers.are'eproducedherebutthosewhichfollowgiveagoodoverviewofthepresentstateofknowledgeofthisfaultzone.ClarkandBrabbdiscussthedetailedstratigraphyoneitherrsideoftheSanGregoriofaultinitstypearea.Theircarefulobservationsoffundamentalstratigraphicdifferences,implysignificantdifferencesinsedimentationandtectonichistoryoneithersideofthefault.GrahamandDickinsonusethis'Iandotherregionaldatatoinferupto115kmofrightlateraloffset.on,thefaultsinceMiocenetime.ThisfigureislargerthananearliersuggestionofSOto90km(Siver,1974)basedonoffsetbasementterranesusingoffshoregeophysicalcontrol.~~Anestimateof80to100lanofpostMiocenerightLateralAoffsetontheHosgrifault(Hall,1975)tiesrathernicelywiththeaboveestimatesfortheSanGregoriose~ent,buttheHosgriestimatehasbeenquestioned(HamiltonandVillingham,1977).Hall(thisvolume)brieflyaddresesthesequestionsandproposesapull-apartoriginfox'heSantaMariabasinonshore.ThequestionofcontinuityoftheSanGrcgorio-IIosgrifaultzonefocusesonfourproblemareas:PointSur,CapeSanF-2
~~Martin,.SanSimeon,andsouthofPointSal(Fig.1).ThePointSurregionisdiscussedindetailbyGrahamandDickinson.TheirinterpretationthattheSanGregorioprobablyconnectswiththeSurfaultissupportedbydetailedgravitystudies(Woodson,1973)andarguesagainstaprevioussuggestionthatthemainSanGregoriofaulttraceturnsinlandsouthofMontereytojointhePaloC'oloradofault(Greeneandothers,1973}.Hall(1975)firstsuggestedthattheSanSimeonfaultispartoftheHosgrifaultzone(Fig.2).ThedetailedconnectionbetweentheHosgriandSanSimeonfaultshasnotbeenestablishedandsomemapsshowan'en-echelonoffsetbetweenthesefaults(Hall,1975;McCullochandothers,1977).TheSanSimeon(Hosgri)segmenttrendsoffshoretothenorthtowardCapeSanMartin(Fig.2}.Recentlyflownaexomagneticdata(USGS-Calif.DivisionofHinesandGeologyunpublisheddata)revealahighamplitudeanomalytrendingnorthwestacrossCapeSanMartinandseemtorequiretheHosgri-SanSimeonfaulteithertobendaroundtheanomaly(Fig.2)ortostep0hninlandtoafaultboundingtheeastsideoftheanomaly.IfthefaultbendsaroundthisanomalyitcouldjoinamajoroffhorefaultnorthofCapeSanMartin(McCullochandothers,1977}thattrendstowardthe'Surfault(Fig.2).HcCullochandothers(1977)(theirFig.2)showanorthwesttrendingfaultwestofPointSur(Fig.1)whichtheyextendsoutheastwardtothecoast;cuttingacrossandseparatingtheflosgriandSurfaults.Thisinterpretationwouldimplyadefinitelackofcontinuitybetween
't'eSanGregorioand.Hosgrifaultsinthisarea.However,theirnorthwesttrendingfaultmustcrossahighamplitudemagneticanomalythatliesparalleltothecoast(anomalyMboundedby-1.5nTcontourinFig.2)andthisanomalyshowsnoevidenceofacrosscuttingstructure.TheanomalyalsotrendsparalleltotheSurandHosgrifaultsandmaybecausedbyserpentineintrusionsalongthefault.Structuralrelationsinthisnearshoreareaareobscuredbysurfaceslumping(NcCullochandothers.-theirFig.2),andT.concludethatthebulkofevidenceatpresentfavorsoratleastallowscontinuitybetweentheSurandHosgrifaults.ThesouthernextensionoftheHosgriisalsoindispute.YicCullochandothers(1977)mapthefaultsouthofPt.Argukllo,butHamiltonandHillingham(1977),usingmuchthesamedata,mapitnofarthersouththanoffshorePointSal.Eitherversionraisesgeometricalproblemsofendingafaultwithapproximately100kmoflateCenozoic.c'lateraloffset.Uarioussolutionstothisproblemhavebeenproposedinoralcommuni-'cations,includingabendofthefaultintotheTransverserangeswherethemotionwouldbetakenupincompression(D.NcCulloch,oralcommun.,1977;llamiltonandHillingham,1977)oranoffs'etofthefaultbyeast-trendingfaultsinthoSantaBarbararegion(J.Crouch,oralcommun.,1976).Satisfactoryfielddocumntation,howe.vcr,hasnotbeenreportedandthisremainsanouttandingstructuralproblem.Holocenemovemcnt.,arewelldocumcntcdfortheSanGrcgoriofault(HeberandIajoie,1977;Coppersmitl>andGriggs,this 1~IL~~volume),andstudiesofseismicityconfirmthepresent-dayactivityonboththeHosgriandSanGxegoriosegments(Gawthrop,3.975andthisvolume).ThisinformationiscriticaltoanyplanneddevelopmentalongthecentralCaliforniacoastbecausetheSanGregorio-Hosgriisverynearlyacoastlinefaultovermostofitslength..TheSanGregorio-Hosgriappearstobthe'argestofthe4subsidiary'faultswithintheSanAndreassystem,bothinlength~andoffset.Otherfaults,suchastheHayward-CalaverasandRinconadahavelesserdocumentedoffsetbutalsoplayan/importantroleinthetectonicdevelopmentoftheCaliforniacoastrangesandaredeservingofintensivestudy.F-5 ReferencesCitedCrowell,J.C.(Ed.),1975,SanAndreasfauLt.insouthernCalifornia:CaliforniaDivisionofHinesandGeologySpecialReport118,272p.Dickinson,W.R.,andGrantz,,A.(Eds.),1968,Proceedings.oftheconferenceongeologicproblemsofSanAndreasfaultsystem'StanfordUniv.Pubs.Geol.Sci.,v.11,374p.Gatothrop,William,'975,SeismicityofthecentralCaliforniacoastal'region:U.S.Geol.SurveyOpen-fileReport75-134,87p.\Greene,H.G.,Lee,V.H.K.,McCulloch,D.S.,andBrabb,E.E.,1973,.FaultsandearthquakesintheMontereyBayregion,California:U.S.Geol.SurveyMisc.FieldStudyM.F.-518,14p.Hall,C.A.,Jr.,1975,SanSimeon-Hosgrifaultsystem,coastalCalifornia:economicandenvironmentalimplications:Science,v.190,p.1291-1294.Hamilton,D.H.,andWillingham,C.R.,1977,Hosgrifaultzone',structure,.amountofdisplacement,andrelationshiptostructuresofthewesternTranverseranges:Geol:Soc.AmericaAbs.withprograms,v.9,no.4,p.429.Kovach,R.L.,andNur;Amos(Eds.),1973,Proceedingsoftheconferenceonteet.onicproblemsoftheSanAndreasfaultsystem:StanfordUniv.Pub"-Geo'L.Sci.,v.11,494p.HcCulloch,D.S.,Clarke,'.H.,Jr,Fic.ld,H.E.,Scott,E.W.,F-6
'l~~l~~~'7WandUtter,P.H.,1977,Asummaryreportontheregionalgeology,petroleumpotential,andenvironmentalgeologyintheareaofproposed'easesale'53-A,centralandnorthernCaliforniaoutercontinentalshelf,partA,39p.Silver,E.A.,1974,Structuralinterpretationfromfree-airgravityontheCaliforniacontinentalmargin,35to40N:Geol.Soc.AmericaAbs.withprograms,v.6,no.3,p.253.Weber,G.E.,andLajoie,K.R.,1977,Late'PleistoceneandHolocenetectonicsoftheSanGregoriofaultzonebetweeneMossBeachandPointAnoNuevo,SanMateoCounty,Cali,-fornia:Geol.Soc.AmericaAbs.withprograms,v.9,no.,4,p.524.~Hoodson,N.B.,III,1973,Abottomgravitysurvey-ofthecontinentalshelfbetweenPointLobosandPointSur,California:Thesis,NavalPostgraduateSchool,112p. 1~FigureCaptionsFigure1.HapofcentralCaliforniacoastshowinggeographiclocationsandfaultscitedintextandlocationofFigure'2.Figure2.DetailedaeromagneticmapofcentralCaliforniacoastbetweenPointSurandSanSimeon.Flightlines4had1milespacing,flownnormaltothecoast.F-8
~~~~125I21!200Cg+l'..."".0~'00",~:..~0SonFrancisco'80~pCaMonterey.."~Pt.SurX,.o~0OC.00CapeSonMartin~"'.:.:,SanSimeon'-:.~q~~~O-"~:Oy~P)Figure2,:,SantaPfSot"MarIa:Basin:;:.'.TransverseRongesPl.Argualla"'::.:,~""::.:,,Santa,:,F-9Pij' 35'30'6uMorihloConlourtnltrvol50nT-2means200nTC'o,'.t>C'g'*H,~r'u)~moo<o1SOgI~Kosorifc"lt020Xmp~IoI~(>wrcun~5QSerrcE>>cccCpc<gyes'0 TheSanGrcgorio-Hnsrifaultt(cndparallelsthecentralCaliforniacoastfromitsinter'ectionsviththcSanAn-dreasfaultnorthsvcstofS;mFranciscotosouthofPointSal(Fig.I).Inthisrcportweprcscnton-landgco!OgiccviJcnccforaboutIISkmofriht-lateralstrikesliponthiscomplexfaultzone.On-landandoffslioresegmentsofthefaulttrendarcwelldefinedbygeologicmappingandmarinesurveys(I-I).Conn'ectinglinksremaincontroversial,however.whereinferredthroughshallowwaterincoastalzoneswhereacousticprotilingdataarcabsentorambiguous(5-7).Ncverthc-80GUAI.ALABASINKM0BOOEGANEAOPT.REYESless.chancealignmentof>>cveralwcll-dclincdni;Ijorfalilts>>cern>>Iinlikcly.Fur>>'hcrmore,ifourevidencef'rrightsliponthcfaulttrendisvalid,throughgoingcontinuityofthc,faultzoneisrequired.Thcevidenceforrightslipconsistsofscvcnpairsol'tl'>>etgeologicfcl(turcs(Fig>>.Iand2).Yoncofthc>>careindi-viduallyunequivocal.hutt:(kentogctliertheypresentacompellingargument.Lineargeologicandpalcogcographicfea-turesformingpiercingpointsont'liultplanesarethemosisensitiveindicatorsofstrikeslip(S).Certainoftheoil'sctpairslistedbc!oivarclinarfeatures.butunfortun:itclynuncaretightlycon-strained.Conscqucntly,weshowprob-ablcoffsetranges.Thccommondenomi-natorofIISkm(Fig.2)isourestimateof~rightslipontheSanGregorio-Hosgrifaulttrend.Detailsot'heoffsetgeologicfeaturesareprescntcdclscsvhcrc(5,6),butinsuminarytheyincludethcI'ollowing.I)7%e8udega-Gaalalaf(n(l(-Pilar-ci(osf(n(l(oJJse(pair(asterisksinFig.I).Ga7(7~10-Jt(7.'<II';tttl('l'ItdATTACRIENTGAbstract.7%<<Sea(Circ@or(O-II(>.'ll!rif(nil((r<<n(lIsa('n(po(i('n(offl(('anvIM(If<<asfa((I(sys(e(nun>a%i<%(l(erenn(l'n(v('>een<<lnn((ILSIilun(((mrsofpos(-I'arlv.hlioeenerigla-la((r<<ls(rileslip.Ifs<<.rig%(.clipon(I(eSanr'hodr<<as<<n(lSanGre-gurio-Ilosgrifanl(s<<troan(sforn(os(of(l(eniui'ennval>e(>veen(I((I'<((ific'aniI>,'or(IIAn(eric<<apla(es.sincen(i(I-hliueene(in(<<.Irnr(I(ern(ore.(IN'M(gnila(leofrigl((sliponaP((leog('nepro(a-$<<nAnclreasJin(l(i<<Jc'rreclfr>nn(I(ipris('n(elis.(riha(ionofgrani(i<<l>ase(nen(isr((la('ed('ansi(l(ralllyu%enA><<ug(n<<-R<<e(n(San'regoriu-II<<Ig(irigl((.clipis(al'enin(o<<ceunn(.~III>>CIIV>>liiilllIsiular>:Illuollc(Iiulce>>tral>>tr;indoftheS:inAndrca>>faultg9).Althoughlyingsvc>>tofthcinodcrnSanAinlic:isfault.thcI'ilaicito>>fiultthusi>>thclocal>>tructurdboundaryl>c-tsvccnIranciscanComplexonthenorth-east:indgraniticbasementonthcsouth-wc>>t.Thisprc-SlinGrcgoriof:uiltmaybcnn'scttothenortha>>';inint'err<<d>>truc-turalcontactscpar;itingthcnorth-ernmostgraniticbasementoutcropsatBodegaHeadfromthcFranciscan-floorcd(?)latestCretaceousand'e;irlyTertiaryGualalab;(sinivcstoftheSanAndrcasfault(/0).2)I'O'In(Revessec(ion-DenLun(on(Ihloan(ainsec(iunoffs<<((x'sinFig.I).DistinctiveTertiarysections,includingunconformity-boundp;lcl'agesotI'i(lco-cenc,middleMiocene,andupper5(io-ccnc-Plioceneage.aswellascom-parablegraniticbasement.occuratPointRcycsandBcnLomondMountain(II-I3).3)PigeonPointFora(a(ion-San(aLu-ciaCre(ac<<o((suJlsetpair(A.sinFig.I).UpperCretaceousdeep-scafandepositsofthcPigeonPointFormation(!4,/5)andanassociatedCretaceousbasinm;ir-gin(6)areprobablyofl'seifromsimilarfcaturcsintheSantaLuciaRange(6).Inaddition.preliminarystudiessucgestthatOligo-I>lioceneshallow-todeep-ma-rinefaciesoverlyingthePigeonPointFormation(l6)mayhaveoffsetequiva-.lentsinthcSantaLuciaRange(5).4)OJfse(ufogsl(oreravi(vridge(Fig.I).Silver(17)proposedthatalineargravityfeatureoffshorefromAnoNuevoSFBPlSANPEOROPESCAOEROPIGEONPT.$)FhiAN0NUEvoPT.qBENL'OMOMOATN.Ae(LARCITOSFAULTSALIMIAM/CCFRANCISCAN~S0CONTACT~SANSIMEON~Ii>>DDXc>>>>>>>f'(MBA>hr>>5+CL<<'JPT.SAgSt:II'.I(L'll,VOI..IVV.I.lJANUARY1>77>Il35l25IPOINTREYESIBENLOMOMOOFFSET05IIPIGEONPOINTISANTALUCIAOFFSETA>70MUEvo-SUROFFSETtsILVERI((7I-l(5tdcCoolo5ILI-95O115GUAI.*LAPILAACITOSOFFSETKMCOMMONPOI(ITSUR-CAMQRIAOFFsETPARTIALOFFSETOFBIGSURMiOCENEOFFSETSAMSIMEOM-POINTSALOFFSETINALLI80(7CGhIICnOIOOKM200KM300iiKMWI>8EACMI.ATERAIpos!TloNSor-oFFsETMlopolNTSALONGSANGREGORIO-I.IOSGRIFAULTFig.Ittcf().SI:>(>ufBcutnuiefC:>lu(csUll'ic(inarighth>(crit>>CI>iCalongihcsh>nGrc('<>(h>-II(>iI:(iIhi>liI(CIKI.Scctealfa>'(liicuii>h>>I.I(ig.2triuhlhO(l'sctrangeclni(tf>>rSI>KI'col<
il'>>ctI>>.iisih>>>v(IinI>ig..lI>(I>Idi>>c<>c>IinIhctext.(Kl'l(>.t(U75(7KAI(I1I>(795(>I).5(VIIC>>Py>ighiCIV(KhhhBG-1
~~~4PRCSCNTNQRIWRNIIHTtYSALONdiSCNCNT>00KMP'PMIOCENEOLCENEpALEO.Ct(ETACEOuqPACIFICN.AMERICANPLATES(RTNATCRdNDLNRR>ISTS)nOrXOVlnAI)NCNTNCANL~DFSRVNMNQRSCNCNT,FSS>~.hGhLACNCSANAXSRCASleJVCNCNTL<N.SCTOOIw~GOOXw5009400C$~~~~~>~~ill+rPROTOSANANDREASotIMOVEMENTONJIill,SAttANOREASFAULTSANGREGORIOACT>VITYPROTO-SANANDREASMOVEMENTIM'X)CONSIDERINGSANGREGORIOFA>f~T1000Co1000AGE(MYBP)OTHERFAULTSMOVEMENT(MAX)DISREGARDINGPOTEtitlALCUMULATIVESANGREGCROIrINDISPLACEMENTSANANDNEASSANGREGORIOCONnIIh0>&CRNVwTDrSRLR><ANSRSCNCMTR(STCNSNCOXICSCNAhCRCASd$AN~~ltQVClcCNT:1T'/TTIPOLCTIN>0SANAICACASDTTSC'IILFRQQASLCLI>OT&SCITIANOASC+CNTFig.3(left).NorthernlimitOf'SalinianblockafterrestorationofNcogcnerightslipontheSanAAdrcasfaultalone(A)oronthcSanAndrcasfaultplustheSanGrcgorio.HOsgrifaulttrend(0).Theremainingo(Tsctofgnniticb:iscmcninoiaccoun(edforbyNeogcaerightslipmaybe0measurenfrightslipon0pro>o-SanAndreasf:iu(1.Fig.4(Tight).(CurveA)Time-Of)setcurve((2)mndi(lcdtnShowthee(feetofSanCtcgorio-Hi>sgirightslip.(Curve0)RelativemotionofthePaci(icandNorthAmericanp(ates(33).Seetextfordiscussion.Pointistheoffsetexpressionofthccon-tactbetweenFranciscanrocksandgra-niticbasementofthe.SalinianblockintheSantaLuciaRange.5)PointSnr~Francisran-CarnhriaPinesslabnfJsetpair(underlininginFig.I).TheFr~nciscansubductioncomplexofthecentralCaliforniacoastisgeneral-lyapotassiumfeldspar-freemctascdi-mentarysequence(IS,-l9).Exceptionstothisgcneraliza(ionarcstructuralblocksofpotassiumfeldspar-bearinggraywacke-shaleatPointSurandCam-bria(IS,/9).Thesetivoblocks:ipparcnt-IyhavebeenoffsetbySanGregorio-Hosgrirightslip.6)PointSarItliaeenesarttlstone-Frarteisettrtsttnreeterrrtne<>/setpair.hfiocencs:indstoncoccupiesusn>nllfitful(sli<<civithintheSurfaultzoneseg-mentofthcSanGrcgorio-flosgrifaulttrendne;irPointSur(5,2tI).Dcspi(ctheImn>cifliltcplox>A>ltyolI'.r;lni(icb>I!icnlcntcxpi>hcdiAhliocct>c(talc(5).(hcs;>Add(oneh:lh'tillcxcl>>SILL'lyI'rilllc>si:allprovenance(5).Atlc;ih(60ktnofrightslipi>>requiredtoproviilcanadequateI'ranciscaiisourcetcrranc.'I'hcol)'sctcannotcxcccdl05kn>.hoivcvcr,bc-ci>u<cth>>silllds(ot>cI'l.ksvole>it>lccli>s(stypic;ilofhtioc<<ncsi>>>>(Stot>csnear('>mbri:>(I).TlicIi>L'killovLI'liipofLII)hctbc('ivccliIhcIi'I>AtSul'i>oct!Ac)inifs(L>ncanilotl>crotl'hLIp:iirs(I'ig.2)LILTCSt>O(LIL'lL"it(hcollhCIIll'i',lllni;AI,bcL;iilsc(hi;Miocct>ctai>llifh(oi>L'hlnaIilul(sliceincorporatedinthef'aultzoneatanintermediatedistance.7)SanSinteonopltiolite-PointSrtloyltioliteoffsetpair(doubleumlerlininginFig.I).Hill(22)reportedtheprobableoffsetofaihfesozoicophiolitcandanoverlying"Per(farysequencefromPointSaltothcSanSimeonareaalongtheHosgriscgmcntofthcfaulttrend.DisplaccmcntofthePointSal-S;mSimeonophiolitcassociationalongtheHoscriscgmcntoccurred5tol3millionyearsago(22).Otherof)'sctindicatorsdemonstratepost-carlyMioceneandprobablepost-middleMiocenerightslip.HoloccncmovcmcntisdocumentedforonlandandoA'shorefaultscgmcnts(2~)Graniticb:iscmcntof'hcS:ilinianblockwestof(lieSanAndre:isfaultisollsctby>IA>inii>>i>11>of5lt)kn>.biiscdonnor(hcrnmostgraniticcxposurc>>atBo-deg:>Head(Itig.I).Ifgraniticbaden>cntextendso(l'shoretoI'ointAren:i(2I).thcmaximun>oil'scti>>600km(Itig.3).Rcs-toritionof'vcll.documcntcdpost-Iiv-ccncSanAndre;isrightslipol'05kin(24-?6)bringsthc>>orthcrnlitnitofS:ili-'i:inb;iscmcnth:icktopositionAinIrig.3.Tl>cdill'LrcnccbctivccnpositionA(Itig.3);iniltheno)tl>ivcstliit>itofSicr-rilnlu>Ken>cuth;Isbccnttlkcn;Is;In>i'.,'I~)dircol'rc-Ioccnc"proto-8:>I>Aii-ilrc:is".rightslip(27.'8).()IlierrLI(ioi>alcviilcnccpk>cch(l>isilcl'orni:>(ioninI';I~lciiccnctitnc(5.29).Iloivcvcr.thcILVA(o.G-2IrationfailstoconsidertheextensionofSalinianbasementby!15kmofSanGre-gorio-Elosgrirightslipnorthofitsinter-sectionwiththcSanAndreasI'ault(22.p.f293)rThcrestorationofthisadditionalII5kmof'NeogenetoRecentrightsliptoposition8(Fig.3)reducesbyone-thirdorperhapstwo-thirdstheapparentright-slipof)setofthenorthernlimitoftheSa-linianblockbythesupposedproto-SanAndreasfault.Furthcrmorc.inthcun-likelyeventthatthelimitofSicrranbase-mentactuallyliestothenotthinthesub-sud;Icc(30),AndifBodcgafleadisnearthenorthernlimitofSaliniangraniticbasement.thenaproto-SanAndreasfaultisprccludcdalongthemodernSanAndre:>spathwayincentralCalifornia.Inanycvcnt,thcproto-SanAndreasfaultapp;ircntlyLvasnotatransformf;iult:in:ilogoustothcmodernSanAn-dre:isI'aiiltsystem.Instc:>d.proto-SanAndre;isf:iultingmayhavebeenthcgeo-logicrcsohttionofobliquesubductionalongthccentralCaliforni:icoastinciirlyTcr(iarytime((I).Righ(Slipof'hcS;mAndrcasfaultiscoaveAlen(lyiflhpkIycif;I',I;IIln>L"illsplaccn>cntplotoncurveAinI'ig.0(.'.).Thcilottcdn>1>dili<<;i(ionnl'curveApriorto60Inillionyc:Ir>>agoshoivsthec(l'Lc(ofdisrcg:>rilingS;inGreg>irio-Ilohgririgl>tSlipinproto-S:>I)Anilrc:ihf:Iultin-tcrprc(:itious.CurvellinItig.Ishi>>L>IhcIeh>(lvi:lnovL'AIL'}ltlic(ivccn(lieI,iI'>IllilailHo>(hAnil,>'leanpkl(cs(I)SCII:.NEI:..Vot..Iv) i~~~iSYithihtheiinccrt:<intyofIhccurves,(AOStn<OLCIACntlv<<tLVCCAtlicplatCSl)ASbccnloe:ilircd;ihuig(licS;<nAndic;i>>faultproperI'vrthclait6niillivnyears.Bctsvccnth;it(imc:uulthcc;irlycaIio-ccAc,A<As(oftilepl<it<<Ill<1(ioAwasillstriivu(<<<lbc(LLC<<nthcS;<nAmlrcas:uidSanG<'cgorio-Ilvigrif;iulttrends.Ti<usthcprcscntextcniionofgraniticbi<ce-mentofthcS;ilinianbio;kinI:irgcpartisexpl'<incdbyrightsliponf:iultsofthcNcogencSinAndre:is(nuitiyitem,assuggcstcclhyJohnsonandWorn<<:rk(34).S.A.QRAHA>ctFrplnscsfios<Drparlsnrn(,11'csternRegion.ChevronU.<.e'L.Inc"a,SanFs'csssciscu.Cc<1%rssicsS)4I/9<<Y.I(..DICKIHso~DCp<<fin<msOfGC'OIOJLV.SICSS<fs)rclUnivcfsily,Sf<<<<ford.CaliforniaS)43053-d:iyperiodonhnlnsmilk.Never-(~8,pilp!iof<illclgcsLliiplclyfcililcc,'cl%)%fit;1<NIILipLl<cvcloplncntLvllcli,nursedonI<<sin)milk.lnanattempttodc(cimincthccaiiscofdc;ith.tissuesectionsfrom.thcaf-fcctcclpopswerccx:imincdhistolvgi~cally.Thinsectionsofskin.lung.liver.stomach.bone.andmusclewercpre-paredfron)((-d;<y-oldpup>>nursedonIsnlnsmilk.Thesectionswerest;iinedwi(hhcmatvxylinandcvsinandexaminedundertliclightmicroscope.Onlythcskinappc;ircdabnnrnial,displaying.fvcal;iciltcclefill;ltltis,gcllc.'I",llUlldcfclcvclopment.andI'olliclcatrophv.FL<r(hcrmvrc,thcstritumgfanulosumw'issignific;intlythickenedandthenumberofhairsh;if(smarl'cdlyreduced.Allotherorgansap-pearccfnor<nal.thoughundersized.andnocvidcnceofinfection,allergy.orin-completedigestionofmilkwasob-sc<'veil.Histologicalobservationsiverealsomadeofmammaryglandsot'n)losd;imswhosepupswere'closetodeath.Ingen-eral,thcscglandsappearedlessactiveandsmallerthan(hoseofnormal8/6mice.Moreover.weobservedthatIs<<isodamsfrequentlyyieldlessmilk.Tal'entogether.thesesymptomsaresimilartothosedescribedbyl<IutchandHurley(3)inratpupsnursedondamire.ceivingapostgestationalzinc-freedict.Thi>>dictleadstoasopercentdecreaseinthezinccontentofthemilkbydayISoflactation,withonlyminimalctfectsontheotherconstituents.Asaresult.nurs-ingpupsa'eseverelydepletedofplasmazinc.1Lvo-thirdsofsuchanimalsdiea<Hiallexhibitretardedgrow(han'dseveredermatitis.Nloreovcr.totalmilkproduc-tionwasreducedhy50pcrccntinthczinc-dcficicntdams.Bcc;<L<seofthesimilarityofsymptomsbetweenthcdietary-inducedzincdcfi-cicncyandthelrflusl<<sill'yndrome,wecomparedthcconcentrationsofzincinthemilkofInihnandnormalmice.AsshowninTableI,thezinccontentofthcmill'l'utantmiceisreduced34per-centfromthatofnormalB/6mi<<c.Thisdill'crcnccisscenthrvuglioutlactationandisrc(lcctcdinthcwholebodyzincCOnC<<ntratiunSOfS-clay-VI<ISOCklingani-mals.Ilowcver,Lvcfvunilnvsuchdeti-cicncyineitherthephiiniaol'lactatingIs<ills<LI,'lillsiLlflntlicc;ifc,'<sacsot:<<lilt(Is<siss<fcn<1<lcs.Sill<.'C><chil(is<siss<Ic:A1<<lciexhibitnorm;ilconccntr;i(iongOI'ot;ilhvdyzinc.it:ippc:<rs(hatthemut:iticiiiinvolvesre<inc<<LItrini(orto('zincfrompi'<in<<:I<1<liilk.IhcIt.'6d:in<8niaint:ii<1;I2<ii<<co<ieciitfatloniuthc<<iilktliatiitcntliilcsh<1',tie<'tlililthiltislIll<<plilii:li<right0197>8AAAS1stJ,C.Clack.disc<<<<a<ion.Stanfoidt<nivccvi<y(1966).I),C.Rove.U.S.Grul.Sun..I'rc>f.I'cip.698(1972).I,C,Cro>>c)l.Grul.Sac;Am,Bull.68,993(1957)~U.R,Lowe,Ivoc.24<hIns.Crnl.Caner.6.7S(1972).J.C.C)acka<adF..E.Rcahh,C<rlif.Div..<(InesGrcil.Sprr.I'cp.,inprese.E.A.Silver.(irc>I.Sc>e.Ani.Ahssr.P<c>gsccrnc6,253(1974).W,Giihcc<.Ca'<il.Sor.An<.Bull.84,33)7I)973)..J.)(su,C<r!i%Dias.LtfnrsCrul.Sprr.Rcp.JS(1969).P.D.Track.Bus(.Drp.Groi.Uni'.Culif.)3.)33(1926)C,A.Hall.Jr..U.S.<7ruf.Srrcv..<fisc.FieldSr<cd.,<fup.LII'L'9((974).,Srirnc'r198.)29(()975).F.A,Silver.J.R.Cue<ay.A.K.Ca>per.inG(,girGuiIrs<IIvnrshrnCora<Rarer..PainsRrycsRrgsi>n.Crrir)i>micr.J.Il.I.ipps;indF,.h(.h)oores.Fdc.(GeologicalSa>eic<)iSavca-men<o.Calif,.19~I),vo(.I.pp.IIi<.W.R.Uickincon.D.S.Cowan,R.A.S<<h>>cick-cc<.Anr.Ass<>'.Pc's.(ri.Bn<S.So.3c(l91kV.h(a<<hews.I(t.i)ii,f.60.2128(1916).T.H.Hi)scnandh(.)I.Link.inI'ir<c<ieriirSvuipusiun<.D.W.Lvcaver.G.)In<no>lay.*.Ti(><a>n,Eds.(Soie<yofEconomicPa<<<on<o)-ogas<sandhtincca)aig<c<s.Tulsa.)9151.p.367.J.Suppe.Crul.S<>aiAcn.Bull.Sl,3253(I'9<0).R.W.Kic<)cr.Z.F..pe<<<<man,D.C.Ro>>.D.Go<<fcicd,SsanfurdUma.Pabl.Grot.Sci.S.339((973).Forcsamp(e.sccS.A.Graham.Iv'ra<<mrSvrn-posiuni.*.E.Fri<vche.H.TccBes<.Jr..W.LV.Wocn:<cd<~Eds.<So<<ia<yofEconomicPal<<un-co)ogii<sand~1(nccatogis<s.Tu)sa.1976).p.125.Secihcdu<<cdlincinFig.3.P.J.Coney.Grus.Sor.Am.Sprr.Pup..incecce,IodificdfromchccucvesofDiekinconrcal.124)andHclvenandLink<26)inac<<ocd.ancewi<)iahtiocencPliocneboundarynear5millionye.icvago.(rocade<ail<<ddiv<<ussionsccGraham<5<.T.A<wa<crandP.81o<nar.Ss<<nlurdUniv.,Pub(.Grus,Sri.13.136(1973).I,D.Johnsonan3LV.<Ho<mack.Grolngy2.II((914).OurccveacehwassupponedinpartbytheEarthScienceSec<ion.NationalScienceFounda<ion(gian<UES1=01728).htay1977;revised22Augusi19771617v021231516Referencesand!Co<es'>728I.A.K.Cooper.U.S.Crul.Su<v.OprnFilrRrp.I901((973).p.65.2.G.E.'Wchec.Geol.Soc.Am.Ahssr.Programs9.524(1977).3.H.G.Gccne.LV.H.Lee.D.S.8(cculioC.E.E.Bmhb.U.S.GrnLSun..'<fisc.FieldScud.hfnp<IF;<I811973)4.H.C.LVagncr.U.S.Grol.SrrniOpenFilrRrp.(1974).S:S.*.Ciiaham.diss<<<<a<ion.S<anfocdUnivccsi<y(1976),'p.5)0.6.andW.R.Dickincon.CalifDiv..ifinrsGros.Si>rr.Rrp.,inpccss.7.E.A.Silver.Gaul.Snc'.Ain.Ah<sr.Progranis9,500(1917).8.J.C.Cro>>eil.Gros.Soc.An.Sprr.Pnp.ll(196).p.61.9.forecamp(e.secT.H:Ni(venandT.R.Simon(.Jr.,J.Rcs.U.S.Grnl.$<<n.l.439<)913).(0.C.ht.LVcm>>ocih.Ssunfi>iclUniv.Pabs.Geol.Srf.I(.(30()968).1(.A.J.Galloway,Calif.Div..<finrsGroLBull.202((977).19303132333523ZincDeficiencyini<<furineIXIilkUndcrIicsExpressionoftheLeIIIal(7<1'ilI'IIII)iver((t:((ionArcccssivcmutation.designatedle-(lailnsill'lns).Lv:<8diicovcrcda<nongniigcofthcCS"sIIL'6J(l)I6)striin(I).Pupsnuriedoni<<iliad:iin>>exhibitstunt-cLIgroi'vill,;<elite<le<'ill;lli'Ils,alopcci;1~andLlc:ithpriortoLvcanin.SincenormalBI6pupi(I.nsl.ns)dicrvhcnnuricdonIn<losinilk,(lieclcfcctrciial<<iin(hcmilk.Ilvlcoic<',linln<pi<psdcvclc'>ptlol'<ll;illyiffiiitCr-nuriC<lVn;iAO<in:ilClam.(.>C-nctic'in:ilyiciinalic;itetliatlnsiiloc:i(cdVllL'hi'La<llviO<11<<(<lidilll(si),6\:el<(inlol'I'inilio>>1(lic;igootihs)loci<i.IllccllcctsLa(lssslsssI<Ill(iclll1<a)who<iipupspcriiitatAIIi(agesoflactation(2).a<Ye,h;<vcevnfircncdtlmtncvvbornsfv>>-tcrcclonlnslnsdan<8'itmid-lact;itinnorI;i(chie(:<(ion;ircais<<vc<'c'.IV<itl'a.'clediis(I<useAll<'i<<LI(fL'<1<1(liebeg<An<A<:ofI;<c(illion,In;<clclition,Lvchavefoun<I;1Llif-fcfcACCilihusccp1<l'ail<tvtvthcc(lectsvflnslsn<<<ilkcvithrcip<<cttvthc<)'.cOI'i<pi.>i(owl<of<ipl<ps;<lc.'f<'cvcfillslyco<An<i(teiltoif<<1<th:1('Icf3d;<yionIn<losA<ilk.cvciiwh<<iisiihscquvntlytfani-(L<<cclI<<:iiio<<>>:il.I'cni.()hlerpiipi,ontli<<otlicili;iiul,Ii;iviiigniiric<loiiin<i<n;ilniill('r,uiccvd.iys,I'<irqucntlyh<<rviVC:<0<)3(>g<<)ss7<LS)l)Juu<(s<>a<.5<L'0(:opySCII!h<CILYUI..IV'S,IJJA'St<A)tv)><78Abstmct.Tlsrinahilisyc>fnursingpopsIosorvivransssiII'fnss'ccI<os<so-i'gosssforIherc'ccrrivr'nuslali<<n.Icthilmilk(Im).isccsrrrlalrdi<<illsarrclocfianin-issclevelsofboll<ss<ilI'nclpopcarcass.rlcln<inislrasiouof-ini'spnpsssssrsingonImlm.cl<<nssrrdssccsIln'lisrrvc'clsnorsalily<<nclssusrbsclilv.IIissaggc'sfrcllhnlIm<<l(crs-inclransporlfreonnsafcrsusll>lci<iclscssssilI;<<nclslscssii.rssssclynusyproviclc'srfsslinfarnsa-clionforunclrrssandingslsc'are'susnassdisease,cscrridcrn<afisisrnlcropashic'<<.G-3
~y~,
4~Roprinlcdfrom'6Docombor1975,Volumo190,pp.1l294SanSimeon-HosgriFaultSyhten),CoastalCalifornia:EconomicandEnvironmentalImplicationsTheSanSimeonfaultterminatestheArroyodclOsofault,whichcutsthroughthelowerpartofthc12-mterrace(l.4).ThcPl<<istocencterracedepositswithintheregionarc130,000>30,000and140.000+20,000yearsotd(5);thereforethcAr-royodelOsofaultisyoungerthanapprox-imately130,000yearsand,atleastinpart,thcSanSimeonfaultmustbes(illyounger.Anepicenter(dateunrceordcd)islocatedontheArroyodclOsofaultandthcmag-nitudeoftheearthquakeisreportedtohavebeenbctwcen4.0and4.4(6).Holden(7)reportsearthquakesof26Octoberor26November1852andIFebruary1853atSanSimeon,where"houseswereinjured.nHowever,theauthenticityol'heseearlyAbstract.Therehasbeen80l'ilomerrrsorntoreofrightslipalongthelateI7unIernarySanSimeon-llosgrifaulIsysremofcaasralCaliforniaduring"thelast5Io13millionyears.Parrofanoil-richbasinisProbablyogserbythisfnulIsystem,andIht'sysrcmmaybeapotentialha:ardIonearbyslrucrures.Comparisonofstratigraphicsectionsex-posedonoppositesidesofthclateQuater-narySanSimeon-llosgrifaultsystematPointSalandnearSanSimeon(Fig.1)stronglysuggestslarge-scalelateraldis-placement.Thcnatureandagcol'trikc-slipdisplacementalongthefaultsystemhasimportanteconomicandenvironmen-talimplications,foritsuggeststhepossiblelocationofanofTshorcextensionoftheoil-producingSantaMariabasinandindicatesthatthcsystemposesupotentialhazardtocnginceredfacilities.ThcSanSimeonfaultincoastalcentral'alifornia,firstnamedin1974(I),canbetracedonlandforadistanceofapproxi-mately19km-thatis,'romRaggedPointtoSanSimeonPoint(Fig.2).lntheareaoffshorefromRaggedPoint,HoskinsandGriAiths(2)showa65-kmnorthwestwardextensionofthcSanSimeonfault.Silver(3)reportsafaultwithasmuchas5kmofdipseparationintheolTshorebasinsouthofPointSur(thatis.80kmnorthofSanSimeon),whi<<hmaybcthcnorthernexten-sionofthcSanSimeonfault.TheSanSimeonfaultmayalsoextendfarthersouthfromSanSimeonPointtonearPointEstcro(Fig.I)inthcutTshore,aspostulatedbyothers(l).Suchasuggestionissupportedbythefactthatthecoastlineisstraightandrisesabruptlyfromthesea.NearSanSimeonPointthetraceofthcSanSim<<onfaultisconcealedbylatePleistoecncorHoloceneslightlycementeddunesandd<<posits.ltfaultsthe122-mPlcistoeencterraceapproximately5kmnortheastofPointPi<<tlrasSlaneas,butdocsnoteutthe12-mterra<<<<neareitherSrcaker1'ointorRagged1'oint.TheArroyoLagunafault(Fig.2)isbe-lievedtobearelatively>oungerandmorcrecentlyactivestrandol'heSanSimeonfaultzone.Thisfaultism:irk<<Jbyapro-noun<<edlin<<arvalleynorthofSanSim<<onPoint(4),hya75-mfaults<<arp,andbyfaultingofthe122-mPleistocenet<<rracc.Thefaultcrossess<<v<<ralwest-orsouth-west.drainingcanyons,includingArro>ollondu.ArroyodclusChinos.andthreeotherunnamedcanyonsbetweenArroyodclosChinosandArroyodclaCruz(4).Eachcanyonismarkedbyrightlateralde-viationof150to450m:however.thefaultdoesnotjuxtaposemarkedlydilTercntrocksequencesortypes(Fig.2)asdocstheSanSimeonfault.'.~coCoooSooMofloIo+ROSSOOPtooVROCOOITZPl&44ooBloncooI>>B4II~~oo54ooooSooSnoOOIIPIPoloRootoo0eoCOolnooILov,poopoQPlfOI~IoChXoTIlOOvMonoBogrollaPlSooLIoooClY,tVrovoooCgoo/C)caXnOIOBroncoOrvhot;OIOI0lOoIIlooPonoonoPlLonoocPlAIOOOOOPtConcooloo>>>>MooLOCOInoI1BioI'ig.I.Locationul'ihcSunSilo<<unIlutgrifaultsystem.I)usemupicfrnuiJenningsIII)unJseveraluthersources(I.Z.4.u.IO.13).inputsinJit~tchypuhyxsllplugsoftheblurlaItu<<k-IslayIlillturn.plex(I,IO,I7).
earthquakereportshasbeenqucsti(8).ThcSanSimeonfaulttcrminatcsthcO<<cani<<IVcstlluasna-Sueyfaultsystem(Fig.I).TheIVcstlluasnafaultmaytcr-.ntinatcthc)idnafault(9).whichinturndispla<<csI'Icistoc<<ncantilateI'I<<istoccncdeposits(9).Thus,althoughmov<<mentbe-gancarlicr,probablybctvvccnthclateMioccn<<andlatePlio<<cnc,th<<SanSim-eonIaultmustbePlcistoccncoryounger.andstrandsorassocitt<<dfaultsmaybcevenyounger.ThcHosgrifault(l0),alsocalledthcEastBoumlaryfaultorfaultzone(I),ex-tendssoutheastwardfromnearPointPiedrasBlancastonearPointSal,butsouthofPointSalthccontinuationisnotclear(II).Seismicreliectionrecords(I,l0)showthattherehasbeendipsepara-tion,withthcwestsidemovingdownrcla-tivctothccastside.Di}Tercntialmovcmcnt'hasoc<<urrcdintermittentlyalongthcHos-grifaultfromlateMiocenetoHolocenetime(I).Earthquakecpicentersalongthe~ssThcrocksinthcI'ointSalareahaveccnd<<scrih<<dItyIVoodringandllram-'ash<<cnd<<scribedhyIlopson<<ral.(I5).Thcold<<strocksinthatar<<aarcthoseoftheJurassic(~l60milliony<<ars)ophiolit<<,whichconsistsofalowerpartofs<<rp<<ntin-itc.layer<<dultramalicro<<ks.andgabbro:andanupp<<rpartofdiorit<<.quartzdiorite,adikeandsillcomplex,andsubmarinepil-lowlavas.Greenish-graytulTa<<<<ousradio-larianchert,overlainbyJurassicshaleandsandstone.r<<stsonthcophiolitccomplex(I5).Asimilarsequ<<n<<cofrocksoccursnorthol'S;mSimeon(I'ig.2)betweentheArroyodclOsoandSanSim<<onIaults,butthclowerpartofthccomplexprcscntnearPointSalisappar<<ntlyahs<<nt,asarcthcsubmarinelavas.inthcSanSimeonarea.AJurassicophiolitccastof'IvlorroBay(13.16).castoftheSanSimeonfault,andinrelativelycloseproximitytoSanSim-eon,isoverlainbyrcdradiolarianchert,notthcdistinctivegreenish-graytu(Taccouschertwestol'theSanSimeonfault.ThcFranciscanshale(Fig.2)intheSanfaultsuggesttllatltcouldhcsclsnllcall~active(I,IO,l2).Arpuntcntssupportin~amlrefutingth<<possiltilityofstrike-sliplcttc(/4)and.morcrc<<<<ntly,tileopltiniitc'novcmcntalongthcllosgriIaulthavebeencaret'ullyr<<viewed(I);how<<vcr,newdatapresent<<dhercstronglysuggestthatthcSanSitnconand}losgrifaultsarcpartofthcsamesyst<<m,rightslipaccountingforthcdistributionol'urassictoPlio<<<<ncrocks.RecentgeologicmappingnearSanSim-eon(4)andthcareab<<twccnSantaMariaandSnnSimeon(9.I3)(I'igts.Iand2)hasshownthatremarkablesimilaritiesexistbctw<<enrockswestol'heSanSim<<onfaultzone,nc:trSanSimeon,.andcastofthcIlosgrifaultnearPointSal(Fig.I).Ju-rassicophioliti:,ovcrhtinsuccessivelybytulTaccousradiolarian<<h<<rtandJurassicshale:Oligoccncnonmarineconglom<<rate,associatedtutf,anddistinctivelandslidedeposits:andlaterTertiarychertyshaleol'imilarcompositionandhistoriesar<<oIT-sct(Fig.3).ThehorizontalslipcomponentmaybcSOkmormore.SueS~NAIXPLA~rsELstoogeI.'lie'e"",QsLosOOtuuSesseeIosse~tsTII'e',eeoseeetssspe5OsTos',PeeeSolresOWsOovota~eo<sssoswsTIONCQOseteROOee~ssLosoovoodoo>>sotooPISO>>OeRI~CIsesles~ss01~Oe>>RsolCOISsoCessseseedodo+ee"oeoUeoLee~IwOeosettOtCaROO.loadsStsotI\IsslRseeelesItoCeesoetO~Sate.avl.t'eeee/esseseeeoeseseSooSeeeossPoeseISIISFig.2.Prc.QuaternarygcotocicmupshnwincdistributionundstratigraphicrelationsoftheJurassicophiulitc,chert,uralsbutcscqucnw.:thcOligocenel.o>>pcI'ormatiornundltluntcrcyShalenearSanSimeon,Californiat4).ThismupshouldbccomparedwithgeologicmapsofthcPointSut-t.iouscudurea(/4,IS),wherethcLuspcFormationovcrlicstheJurassicophiolitcuudshale.Theru<<ksinthcSunSimcun}tointureawouldhavebeenutleastl2kntotfshorcfromPointSulpriortomovc-mcntalongthcSunSimeon-}losgrifaultsystem.Simeonareaconsistsof'darkgreenish-grayandbrosvnweatheringclayshale.Theunitislithologicallysimilartothcl.londaFor-mationol'ibblec(IT)southofPointSal,butitisnotrecognizedintheSantaMariaarea;itispresumedtolievvithinthefaultblocknortheastoftheSanSimeonfault.JurassicshaleintheSanSimeonareaislithologicallysimilartotheKnoxvilleFor-mation(14)intheSantaMariaareaandtheEspadaFormationofDibbl<<e(/7)far-thersouth.InboththePointSalandSanSimeonareasthcJurassicshalecontainsbedsofconglomerateconsistingofwcll-rounded,smooth,small.blackchertpeb-bles.StratigraphicallyabovetheJurassicophiolitc-chert-shalesequ<<nccinboththeSanSimeonandPointSalareasistheLospeFormation(Fi>>.2),anonmarinerockunitconsistingchiellyofreddishcon-glomerat<<andcoarse-grainedsandstoneandtuIToverlainbygrc<<nishsandstoneandtulT(l4).InthePointSalareatheLospcFormation(/4.I5)ofOligoccncagcoverlapsJurassicshaleandr<<stsonthcophiolitccomplex.InthcSanSimeonareasimilarstratigraphicrelationshipsarecomplicat<<dbyfaulting(Fig.2).ThcgreenishsaridstoneisnotwelldevelopednearSanSimeon.InboththePointSalandSanSitn<<onareasthc<<onglomerateisunsorted<<ndpoorlystratified.Clastsrangeinsizefromafcwinchestoseveralfeetindiatnctcrandconsistofrocksfromtheophiolitc<<ompl<<xandl<<sscramountsofJurassicchertandshale.NovvhcrcintheH-2 LospcI'ormationwestofthcSanSin<<<onfault(Fig.2)arcth<<rcclastsol'da<<itcfclsitcfromthc22-million-to26-millio<I-year-oldMorroRock-Islayflillcomplex(9,13.18),thedacitcol'Ro<<kyButte(T1inFig.I),orthcCamhriaI'clsitc(9.le')).Da-citcandf<<!sit<<clastsarenotpr<<sentinthcLosp<<FormationinthcI'ointSalr<<gion.flowcvcr,clastsoftheserocksar<<pr<<sentintheLospeandOligoceneandlowerMiocenerocksonlyafcwkilometerseastofSanSimeon(9)andnearCambria.Thus,theinferenceismadethatLospc~stratawestofthcS:mSimeonfaultzonewercnotintheCambriaareaatthcti<neoftheirdeposition.Clastsol'dacitcandCam-briaFclsitearcpresentonlyinPleistoceneandyoungerdepositsivestoftheSanSim-eonfault(4).TherearevolcanicashortuffdepositswithinthcLospeFormationatboththcPointSalandSanSiineonlocalities.AtPointSalthetulToccursnearthebaseofthcconglomerateandnearthemiddleofthcLospeFormation(14);northol'anSimeonitoccursaboveconglomcratc.SouthofPointSal,nearLionsHead.alandslideoccurswithintheLospcForma-tionbcloivaprominentwhitetutTb<.d(14).SouthofBreakerPoint(Fig.2)alargeOligocenehndslidcoralluvialfanalsoliesimmediatelybeloivtuffandothervolcanicrocksivithintheLospc'Formation.flereclastsintheLospclandslidearemorevari-ableinsizeandlithologythanthoseinthcLospelandslidesouthol'ointSal:how-cvcr,atbothlocalitiestheclastsarcpre-dominantlyscrpcntinite,cabbro.diorite,andbasalticrocks.Thcoccurrenceofdis-tinctivelandslidesorlandslide.likedepos-itsimmediatelybelowatull'edinthesameform'ationattwowidelyseparatedlocalitiesonoppositesidesofthcSanSim-eon-Hoscrifaultsystemstronglyarguesfortheirpreslipcontiguity.Inadditiontothcr<<markabl<<sim-ihriticsbetweenrocktypes,structuralstyles.andstratigraphicrelationshipsofthcdioriteanddikeandsillcomplexwithinthcophiolitcandtothcpresenceofthcLospcFormationnearPointSalandSanSimeon,ther<>anextraordinaryresem-blanceb<<tiveenth<<lithologicsofthcmiddleorupperpartofthcMontereyShaleatthesetivoareas.Inbothr<<ionsandeastandwestoftheSanSimeonI'iiultthereisthin-h<<ddcdchertysliatc-achar-acteristicofthciblontcfcySlialc.Ilowcvcr,westofthcSanSimeonfault.approxi-matelykmnorthivcstot'anSim<<onP(int(I'ig.2).0.3-toI-m-<hi'kII.ol'l:Ick<<h<<rtintcrh<<ild<<divithdiatonia<<coUssiltsto<ic<Ifc<<IsoI)resent.SI)U<hofI'$)intSal,n<<arI.ionsllcail,id<<nticallithologicsoccur(14).III)wcvcf.Intl<$.'sever;IIhi<nFig.3.Pfe.Quaternarycom-positestratigraphicsectionsofrocksinthePointSal-Lionslleadarea,SantaBarbaraCounty(14.15).andtheSanSimeonPoint-RaggedPointa<ca.SanLui>>ObispoCounty(4).PointSt)lLiondVCoo~t<og~uooosJsh~~a~c>>tC0dotaidIOducatOhdOosaeoIOiieoehotel'NII<lottet<Coetotdroeooteoh<<<4llleetirteeeoiahdeoOOStroche5$<<OeOIOOLoiot4hotohfeohrIIIOOtoilIJttoiietIlottJotaSIKihtelOthettdtSonSimeonPointRot)<<et<PointTm+'hoehJIVIden~J,oo.eie.,s'LQo0$C),lcJ<<6)CJ<'CeJsti~++JereC2datohdIurd<oeittahdulttaehahaeOCIIIfthcconclusioniscorrect.thenth<<rcareatleastthreesignilicantcorollaries.I)Thcrateol'motionb<<tweenthePa<<if-icandNorthAmericanplates.between4.5andIOmillionyearsago.averaged4.5cm/yearaccordinctoAtivaterand%(ulnar(20).Therefore,450kmofdisplac<<mentwouldhavetakenplacewithinthelastIOmilliony<<ars.Thiscal<<ulatedamountex-ceedsrightslipm<<asurcdalongthcSanAndreasfaultby150km(21)duringthelastIOtol2millionyears.Sonicofth<<rel-ativemotion.80'kmin5millionto13mil-lionyears,mayhaveb<<cntakenupor;ib-sorbcdintheSaliniablockor-assuc-gcstedhere-olTshorealongthcSanSim-eon-Hosgrifaultsystem.2)TheSantaMariabasincontainssev-eralproducingoilfields(/9).Athicknessof300mto4kmofCenozoicsedimentaryrocksispresentoffshoreI'romtheSanSimeonarea(1-3)andwouldbcpartoftheSantaIh1ariabasinthathasbeendisplIcednorthwardalongtheSanSim<<on-Ilosgrifaultsystem.Insteadofsimplew<<stwardprojectionol'thatpartoftheSantaMariabasin,ivhichiscurrentlyprodu<<inc<<om-mcrcialquantitiesol'hydrocarbons.Un80-kmnorthwestprojectionmightbcmorcvalid.3)ThclateQuaternarySanSim<<on-Hosgrifaultsystemcouldbcapot<<niialhiiz.irdtoany<<ngin<<cr<<dstru<<tur<<lo<<:i<cdalongthccoastI'romSanSimt.'l)nsoUtlitt)thevi<<inityofPurisimaPoint(I'ig.I).C.A.H*t.<.JR.Drpartrr<cr<tofCieoir)gy.UniversityofCalijirrnirr.I.osrlngel<st)N)24ttcfcitncchand.'hutcht.EarthSsicnicA$ioci:Itch<PaloA<to.<'Ii<i<'.h-(ic-olugyofIhc$In<harn(o,iiiitul<'c\Iiui<thc<lii-<itinlltgii<iiililteinil'Ilini'n<.'Iinl.lrrlnIii(.IIII~i<Ill.l,III<<I$ficctaIrile<cliceIiiIncI'I'it<it}'iIn<Iic'IISIIII<Iof<heSant,uthRiinfcaniltii<ctotia$.-re<hit<IorPaci<i<<(eahantiI'<I~<tie('omp.in$iiiciIahli.hihi~<cnuaiSirhciintisacnini<ha<iouhia<fr<<t)iahl.i(.al$)'tillfdili'<intrtoucrt'I.ill<<I'INI.Z.tt(i.<tuiLuihanilJ.It.<iri<<iihqe<ett.C<iioi.l'rr.(Irol.htrett.<S.3<$tte)11)dredsquarekilometersthathavebeenmappedcastoftheSanSimeonfaultandnorthwestol'antaMafia(9,13)thickblackchertbedsarenotpresent.AsmalloutcropprobablyofPlioceneagchasbeenmappednearSanSimeon(Fig.2)withintheSanSimeonfaultzone.Thcoutcropcontainsmarinefossil>>:Den-drastcrspicbryozoa.Den<alias<spicSolensp..andNuculana1Saccella)tapi<ria(Dull.f897).ThefossilsdonotdatetherocksmorepreciselythanearlyPliocenetoHolocene.Thelitholocy.hoivever.issim-ilartothatoftheGraciosaCoarsc-GrainedMemberoftheCureagaSand-stoneinthcSantalvlariaarea(14).Onthewhole,strongstratigraphicandlithologicsimilaritiesexistbetweentwopackagesoffiveorsixlithologicunitsex-posedintheSanSimeonandPointSalareas.Thcdiametersofthcscrelativelyuniquelithologicpackagt.sarcestimatedatnotmorcthan20kmeach(4,9.13-15,19).Rocksequenceswithinaradiusof20toIOOkmtotheeastofSanSimeonareunlikethosewestol'theSanSimeonI'cult.ComparisonofthestratigraphicandlithologichistoriesoftheareasnearPointSalandSanSim<<on(Fig.I),ar<<asthatliconoppositesidesoftheSanSimeon-Hos-grifaultsystem,indicatesstronccvidcnccforrightslipof80ormorckilomctcrsalongthcfaultsystemsincethclateMio-ccncorcaflyPlio<<<<f<c.Itisiissunlcdthats<<parationisequaltoornearly<<qualtothchorizontalslipcompon<<nt.Th>>un-<<ertainti<<sofd<<terminingth<<niinimumhorizontalslipcompon<<ntar<<equaltotheunccrtainti<<s.inoncdir<<<<tion.ol'h<<maxiniumsizeol'hcar<<aofthcstrati-graphicpackag<<s.Thus.tli<<liorizontalslipco<nponcntis<<ailculatcdtohc80k<normorc(tliatis.Uior<<thanIOOkinh<<tween'I'ointSalandSanSin<<<onI'oint,minusthccstimat<<dmaxiiuuin20-LIIIdia<n<<t<<rofthcareaol'h<<str;itigraphi<<p;IckiigcsatS:inSiin<<on;indI',ointSal).H-3 67IOl2.13E.A.Silver.Sa~uinGrrrl.Srrr.ShortCrnrrsr(l974)p.6IC.A.Ii;rllJr..GeologicmapofthcIricdtasElan<<as-SanSimeonregion.Califutma.inptcpr~ration.II.II.VcebandJ.W.Valentine.Grul,Sur'.rlnt.Bull,78.547(l9/rg).CaN/.Drp.It'atrrKrruur.Bull.Iid2(1964).E.S.Iloldcn.Srrrithson.Jlisr.Cullrrt./087(I897).P.Squibb.personalcommunication.hlr.Squibhispataps+identufthcSanLuisObispoCountyi(is.totica(Society.C.A.IlailJr..Grul.Srrc.vlnr.Bull.7)L559(l967):CoNf.Div.,tllnrsGrrrl.,tfupShrrt(l973);U..S;Grol.Surv.3/irr.FirldSturl..t/up.tlF.!II(I')73):US.Urrrl.Surv..tffrraFirldStrrd.Jlapt/F.!Ou(1974):D.L.Tutncr.Grrrl.Sr>c;Anr.Sprr.Pup.l24(l970).p.9I:D.L.Turner.R.C.Sutdam.C.A.Ilail.Grol.Sur.Am.rtbrtr.CurdillrrunSrrt.2.I!5(1970).II.C.tVagner.US.Grol.Surv.OprnFilrRrp.74-2!2(1974).C.W.Jennings.Col%Div.3/inrsGrul.Prrlirn.Rrp.IJ(I973).W.Gawthtop.U.S.Graf.Surv.OprnFilrKrp.7$-IJs(I975IC.A.IlailJr.."GcrrIoki<<mapofthcCayucos-SanLuivObisporegion,'Z.Grol.Surv..rtfisr.FirtdS/ud..tlap.inpress.l4.tV,P.Nrrrrrdt(ngand~Itwmlctte.U9.Grul.Surv.I'mf.Pup.222(~IS.C.*.Ilupvmr.C.J.I:ro,L'.A.I'es<<rgno.Jr..J.M.Matttnwn.-I'tcliminaryrc/NrrtandgerrirreicuidetothcJur;rvsicophiolitcnearPoint.'(al.'outhctnCalifornia<<uast."Grul.Sar.:Iw.Car-dillrrunSrrt.Guldrb.Firld7ripPlu.!(MarchI975).l6.B,hl.Page.Grul.Sar.Anr.Bull.gl.957(I972).(7.T.W.DibhlccJr..Calif.Div..tfinrsBull.I!0(I950).Ig,W.Cr.ErnstandC.A.IlailJr..Grul.Sor.Anr.Bull.8<.523(1974).l9,PacrficSectipn.AmericanAsso<<iationofPetro-leumGcologivts,CurrrlatinnScanionacrossSanta.')/ariaBurinI:(l959k20.T.AtrratcrandP.hlolnar.StanfordUniv.Pub/.IJ(l973).p.I36.2I.O.F.Ilulfman.Geol.So>>.rtnr.Bull.83.29(3(I972).22.Public>>ationapprovedbythedirector.U.S.Geolog-icalSurvey.IthankW.G.Iitnst.G.Octtcl.E.Pampeyan.andII.Wagnerfortherrcrrnstru<<tivecomments.J.GucntherandV.Jonesdraftedthcfigures.ResearchsupportedbvthcU.S.Gcologi~calSurvey.the(qu<<learRcguLnuryCommission.andth>>UniversityofCaliforniaRcscar<<hCom-mittee,29Augustl975:rcviscdl4Octoberl975Copyriyht831/J78bptheAme)scanAssociationfortheAdvancementofScienceH-4 J.iiLInpress,tobeublishedin"SanGregorio-HosgriFaultZ,California,"editedbyE.A,.SilveroW.R.Hewmark,Calif.Div.ofMinescxGeology,SoecialRessort137.ORXGINANDDEVELOPMENTOFTHELOfPOC-SANTAlARIAPULL-APARTBASXNANDITSRELATIONTOTElESANSIMEON-HOSGRXSTRIKE-SLIPFAULT,WESTERNCALXFORNXA.ClarenceA.Elall,Jr.DepartmentofEarthandSpaceSciencesUniversityofCalifornia~LosAngeles,California90024ABSTRACTC~AmodelisproposedtoaccountforthedistributionofCretaceousandEocene.sedimentaryrocks,anddistinctiveTertiaryigneous,sedimentary,andvolcaniclasticrocks'thatliewithintheWesternTransverseRangesandtheSantaMaria-Lompocregion,SantaBarbaraCounty,California.ComparisonsoflithologiesandstratigraphicsectionstendtosupportthehypothesisthattheTertiarySantdMaria-Lompocbasinisapull-apartstructurethatbegantoformabout14m.y.ago.FollowingdepositionofthelateTertiarysediments,thewesternpartofthebasinwasdisplaced,sincethePliocene,nearly80to95kmtothenorthwestalongtheSanSimeon-Hosgrifault'one..INTRODUCTIONAspeculativemodelisproposedtoaccountforthedistributionofTertiaryigneous,sedimentary,andvolcaniclasticrocksthatliewithintheSantaMaria-Lompocregion,SantaBarbaraCounty,California.Geologicmapping,analysesofcoreholes.andwelldata(Hall,1977),andpreliminaryfieldinvestigationssoutheastofSantaMaria,CaliforniasuggestthepresenceoftheSantaMariaRiverfault(Fig.1)andthattheSantaMaria-River-FoxenCanyon-LittlePinefaultzone.(Fig.1)mayextendmorethan100kmtothesoutheast.Workonthifaultzonehasbroughttolightsomeprovoca-tivegeologicrelationshipswhichprovidesupportforseveralstructuralmodels forthedevelopmentofTertiarymarinebasinsalongthecoastofCaliforniaandrelativelyrecentmovementonamajorfaultsystemintheregion.Inaddition,thisworksuggest'sthepresenceoftheinferredLompoc-Solvangfault,whichinlargemeasureappearstorepresentthenorthwesternstructuralmarginoftheTransverseRanges.STRATIGRAPHYImmediatelynortheastofthe'antaMariaRiverfault(Hall,1977;andFig.1),i.e.,within3'to4kmofthefault,thefollowingMesozoicandTertiaryrockunitsarepresent:(1)Franciscanmelange(thicknessunknown),(2)UnnamedCretaceousrocks(morethan457.m),(3)Sespe-Lospeformations(152m),(4)Vaqueros-Rinconformations(304m),'5)ObispoFormation(335-.609m),(6)PointSalorLowerMontereyFormation(304m),and(7)MontereyFormation(1066m)(Table1).TheSespe-Lospeformationsarenotknowntobepresentwithin3to4imsouthwestoftheSantaMariaRiverfault.SouthwestoftheSantaMariaR'verfault,i.e.,withinadistanceof9.7kmofthefault,orinthecaseoftheSespe-Lospe,morethan4kmfromthefault,thefollowingrockunitsarepresent:(1)Franciscanmelange(thicknessunknown),(2)Sespe-Lospeformations(609m),(3)PointSalFormation(228m),(4)MontereyFormation(629m),(5)SisquocFormation(498m),(6)FoxenMudstone(88m),.(7)CareagaSandstone(43m)(WoodringandBramlette,1950;andFig.2).AlthoughthestratigraphynortheastandsouthwestoftheSantaMariaRiverfaultismarkedlydifferent,i.e.,Cretaceousrocks,VaquerosSandstone,andiHnconShale,andinpartSespe-LospeareabsentintheSantaMariaValleyarea,themostsignificantdifferenceistheabsenceofbetween335mand610mofvolcanicrocks,includingvolcanicash(ObispoFormation)withinadistanceof35to40kmsouthwestofthefault,butthepresenceoftheTranquillon volcaniclasticrocks,ofthesameageastheObispoFoxmation,onthesouthwestmarginofthebasinmorethan35kmtothesouth(Fig.1).TERTIARYBASINHISTORYAtleastthreemodelscanbeproposedtoaccountfortheabsenceofrockunitswithdistinctivelithologies,namely,theVaqueros,Rincon,andObispoilformationssouthwestoftheSantaMariaRiverfault:(1)strike-slipmovementoftensofkilometersalongthefaultbringingintojuxtapositionmarkedlydif-ferentstratigraphicsections;(2)theareabetweentheSantaYnezMountainsandtheSantaMariaRiverwasatopographichighduringthetimewhentheVaquerosandRinconormationswerebeingdepositedelsewhereintheregion,andtheObispo-Tranquillonvolcan'crockshavebeenerodedfromthisregion;or(3)thedevelopmentoza'ull-apartbasin(the"formationofpull-apartbasinsisdis-cussedbyCrowell,1974)zollowingthedepositionoftheVaqueros,Rincon,andObispo-Tranquillonzormat'ons.Thefirsthypothesis,namelylargepost-MontereyFormationorObispo-Tranquillonvolcanicrockstrike-slipalongtheSantaMariaRiverfault,isdifziculttotest.Ifright-slipalongthefaultdidoccur,'ttheObispovolcanicrocksformerlyneartheintersectionoftheSantaMariaRiverandSantaMariaMesafaults(Fig.1)wouldhavebeenmovednorthwestwardand'nowwouldbeburiedbeneaththePismosanddunesoxliebelowSanLuisBayinthePacificOcean'(Jennings,1959;HallandCorbato,1967;Hall;1973)-Thesecondhypothesis,thatis,priortothedepositionoftheMontereyshalestheareabetweentheSantaYnezMountainsandtheSantaMariaRiverfaultwasatopographichigh,ortheVaqueros,RinconandObispoformationsweredepositedandsubsequentlyerodedaway,canezplainthedistributionoftheTertiaryrocks.However,theabsenceofCretaceousrocksinthisarea,buttheirpresenceboundingt'earea(Fig.1)andthepresence.ofEocenerocksnorth
~~4iandsouthoftheLittlePinefault,'neartheLornaAltafault'(Fig.1),buttheirabsenceinthesubsurfaceinthevicinityofSantaYnez,approximately15kmtothewestoftheLornaAltafault,andelsewhereinthebasinbetweentheSantaHariaRiver-FoxenCanyonfault(Fig.1),isdifficulttoexplainbythishypo-thesis,unlessoneassumesthattheCretaceousorEocenerockswerealsoerodedIcompletelyoffofaFranciscantopographichigh.Also,subsurfacedatadonot,provideevidenceofunerodedremnantsoftheseunits.Furthermore,ifthewedge-shapedSantaHariabasinwasahighduringorfollowing,forexample,thetimeofdepositionoftheVaquerosand.RinconinorsurroundingtheregionandthedepositionoftheObispovolcanicashinamarineenvironmentwithinthebasin,itwouldrequireanunusualhistoryforthebasin.Theeventswouldhavebeen:(a)thedepositionofthenon-marineSespe-Lospeformations,(b)thedepositionoftheshallow-watermarineVaquerosSandstonefollowedbythedeep-waterdeposited~~conShaleeithersurroundingthebasinorwithinthebasin,(c)thedepositionoftheObispotuffwithinamarine,basin,(3)the'eep-waterbasinwouldhavebeenuplifted,'iththeVaqueros,Rincon,andObispoerodedaway,and(3)the"theareawouldhavebeendown-droppedalmostsimul-taneouslyw'ththeerosionoftheObispoFormationsothatthedeep-waterPointSalorLowerMontereyandMontereyFormationscouldbedepositedinadeepeningbasin.NotethatthebaseoftheMontereyFormationisbetween10,000and15,000feet(3048to4572m),belowsealevel(Fig.1).Thusawedge-shapedhighwould'IhavetopersistfromOligocenetoMiocenewhiletheareasurrounding'hehighwouldbesubsiding,andthenthehigh-standinglandmasswouldhavetosubsiderapidlyintheHioceneandPliocenetoallowdeep-waterPointSal,MontereyandPliocenesedimentstocoverthesupposedhigh-standinglandmass.Comparisonsoflithologiesandstratigraphicsections(Table1)tendtosupportthethirdmodelforthedevelopmentofa.SantaMaria-Lompocpull-apart basin,althoughdetailedstratigraphicandlithologicstudiesareyettobemade.InthewesternSantaYnezMountainsthestratigraphicsectionisunlikethatnorthofSantaYnezValley(Lompoc,Buellton,SantaYnez,,Fig.1),.butit.agreesrelativelycloselywiththestratigraphicsectionnorthoftheSantaMariaRiver-LittlePinefaultsystemnearly45kmto.thenorth(nearSantaMaria,Fig.1,Table1).ThestratigraphicsectioninthewesternSantaYnezMountains(eastofPointArguello,Fig.1)includes:(1)FranciscanmelangeandHondaFormation(457m),(2)Cretaceousrocks(2743m),(3)OligoceneandEocenerocks(1981m),(4)Sespe-Lospeformation(91m),(5)Vaqueros-Rinconunits(213m),(6)TranquillonVolcanics(365m),and(7)MontereyFormation(914m).TneTranquillonVolcanicsarethesameageastheObispoFormation(TranquillonVolcanics:17+1.2(basalt),16.8+.5(tuff),16.1i..6(tuff)m.y.;ObispoFormation:15.3+.9,16.3+.5,15.4+.5,15.3+.5,16.5+.8m.y.;Turner,1970).Thissequenceofrocksdoesnotcorrespondexactlywiththaonthenorths"deofthebasin,namelynorthoftheSantaMariaRiverfault,andareconstructionoftheTertiarygeologichistoryoftheregionpriortopullingapartofthebasinisrequiredtounderstandwhyexactcorrelationscannotbemade.AgeneralizedpossibleTertiaryhistoryofthedevelopmentoftheSantaMaria-Lompocbasincouldbeasfollows.Figure2ashowsageneralizedpaleo-geologicmapafterthedepositionoftheGaviotaFormationofOligoceneageandolderrockunits(Cretaceous,K;Eocene,E).Beforedepositionofthenon-marineSespeFormationtherecouldhavebeenstrike-slipalongtheinferredfault,asshowninFigure2b(diamonds).Later,obliqueriftingalongthisfault(postObispo,postFig.2dtime)wouldaccountforthedevelopmentofthe.SantaMaria-Lompocbasin.Theinferredfault(diamonds)iscalledtheLompoc-Solvangfault(Fig.1).Itsinferredpresenceissupportedbythefactthat northofitsapproximatelocationthestratigraphy(knownfromexploratoryoilwells)ismarkedlydifferentfromthatsouthoftheinferredfault.Figure2cdepictsagenerali.zedpaleogeologicmapbeforethedepositionoftheMontereyFormation.Sespe-Alegriaformations(inpartLospeFormation),VaquerosSand-stone,RinconShale,andObispo-Tranquillonvolcanicrocksunconformablyover-lietheFranciscanrocks(F),Cretaceousrocks(K),Eocenerocks(E),andOligocene(GaviotaFormation)rocks(0).(F,K,E,and0shownasdottedandburiedcontacts)-Thefault(diamond)waseitherburiedorwascontinuouslyorsporadicallyactiveduringthedepositionoftheTertiaryrocksshowninFigure2c.'\Subsequently,aseriesofpull-apartbasinsmayhavedevelopedalongthepresentcoastalpartofcentralCalifornia,onesuchbasinbeingtheSantaMaria-Lompoc5hzbasin.TheSantaMaria-LompocbasinwasprobablylatertransectedbySanzoneSimeon-Hosgrifaultv(Eall,1975a).Afterdeposi.tionoftheObispo-Tranquillonvolcanicrocks,theformationoftheSantaMaria-Lompocbasin(Fig.2d)began.withthedevelopmentalongtheright-sliptransformLompoc-Solvang-SantaMariaRiver-FoxenCanyon-LittlePinefaultsystem,ortherewasrenewedmovementalongthisalreadyextantfaultsystem,'possiblyduringtheLuisianAe(14m.y.b.p.).Themarginsofthebasinwereformedbythe.Lompoc-Solvangfault(diamonds)(orpull-apartshoulder)andtheSantaMariaRiver-LittlePinefault(triangles)(or.pull-apartshoulder).Right-slipalongthefaultprobablyaccompanieddip-slipandthelateMioceneandPlioceneseasfloodedthedeepeningbasin;notethatnearLosAlamosthebaseoftheMontereyFormationisnearly4,572m(15,000feet)belowsealevel(Fig.1),thatthemaximumsubsurfacethicknessoftheMontereyFormationisprobablymorethan1,524m(5,000feet)thi.ck,andthemaximumout-cropthicknessatthemarginsofthebasinisapproximately655m.(2150feet).ItissuggestedthattheSantaMariaRiverandLompoc-'Solvangfaultsarepartofthesametransform-rightlateralfaultsystemandbeforethelateMiocenepull-apart,toproduce*theSantaHaria-Lompocbasin,wereprobablyasinglefaultorfaultzone.TheformationofthelateTertiarypull-apartbasin,withmotiontvectorsofextensionparalleltothestrike-slipfaults,beganfollowingthedepositionoftheObispo(Tranquillon)Formation,probablyduring.themiddleMiocene(14m.y.b.p.).Hallsalongthefaultmarginsmayhavebeguntosagandpullapartasearly'astheearlyOligocene,orevenearlieriftherewasmorethanIoneepisodeofrifting.TheFranciscanrocksareweak,easilyfolded,faulted,andstretchedorbecameevenmoretectonicallybrecciated.Whatoccurredtothedeepercrustallayersisunknown,buttherewasnotmassiveextrusion.Duringt¹openingofthebasinonlyminorvolcanicflowsorintrusions(e.g.,those.nearPointSal)occurredcontemporaneously,withthepull-apartand'thestretch-ingoftheF"ancscan.Rotationalmovement(Fig.2e)orbendingaccompaniedformationofthe.pull-apartbasin.ThismovementresultedinachangeoftrendoftheLompoc-Solvangfault(Fig.2d)fromnorthwesttoeast-west(Fig.2e).Therotationorbending~~ouldaccountforthedistributionfotheCretaceous(K),Eocene(E),andOligoce"e(0)rockssouthoftheinferredLompoc-SolvangfaultandmayhaveplayedaroleinorduringthegeneraldevelopmentoftheTransverseRanges.Thamountofcounter-clockwiserotationisreducedifthe'Lompoc-Solvangfaultinitiallyhadamorewesterlytrend.The'maximumpull-apartisbetween40and.50kilometers.Becauseofprobablestrike-slipalongtheLompoc-Solvang-SantaMariaRiver-LittlePinefaults,theCretaceousandEocenerocks,GaviotaFormation,VaquerosSandstone,RinconShale,andObispo-Tranquillonvolcanic'IrocksnearPointArguelloprobablywereincloserjuxtaposition,.initiallywithrocksofthesamelithologyandagesatthelatitudeofCamuesafault(Fig.1)ornearZacaLake.(Jennings,1959).thanwithrocksneartheSantaMariaRiverfault.Thatis,therocks"southofLompocandSolvang,intheTransverseRanges,havemovedalongaright-sliptransformLompoc-Solvang-Santa'HariaRiver-Little 8Pinefault,thebasinopenedalongthisfault,rotationorbendingoccurred,andtheLompoc-Solvangfaultandrockssouthofthefaultwerebroughtintotheirpresentposition.Left-slipoccur'redatalatertimealongaSantaYnez-Pezzonifaultsystem(partiallyshowninFig.1).Followingthedepositionofthe'lateTertiarysediments(Sisquoc,'oxen,Caxeagaformations),withinthedeepenedbasin,apartofitwasmovedmorezonethan80kmtothenorthalongtheSanSimeon-Hosgrifault(Hall,1975a).Itisunlikelythat.theslipislessthan80km.Evidenceforthisunlikelihoodisprovidedbythefactthatthepackageofrocks,intheSantaMariaregion(i.fe.,Jurassicophiolite.,chert,andshale,LospeFormation,MontereyFormation,andzone'liocenerocks),whichweremovednorthalongtheSanSimeon-HosgrifaulthasadistributionlimitedtotheSantaMariabasin.Atitswidestthebasinisabout50kilometers(30miles).However,itwillbenotedthattheknowndis-tributionoftheJurassicophiolite,chert,shale,LospeFormationandassociatedyoungerrockstha-cropoutnearPointSalareknownfromthesubsurfaceinanareaoflessthan19km(12miles).ThedistancebetweenPointSalandtheSanSimeonarea(Fig.3)ismoethan100km(62miles),thediameteroftheuniquepackageofrocksintheSantaMariaareaislessthan20km,thustheoffsetwouldbeatleast80km,andmorelikely95km.Thereleasinghalfbend,depictedatthesoutheastendofthepull-apartbasininFigure2d,wouldhavehadamirrorimageatthenorthwestend,butthishasbeentruncatedbythe'anSimeon-Hosgrifaultandisnow100kmtothenorthatSanSimeon(Fig.3).ThePlioceneCareagaSandstoneatSanSimeonsuggeststhatthe80to95kmof,right-slipalongtheSanSimeon-Hosgrifaultoccurredduringthelast5m.y.Theearliest'strike-slipmovementalongtheSanSimeon-Hosgrifaultwouldprobablybe9to13m.y.'learlyallmovementtookplacealongthefaultIffollowingtheformationofthepull-apartstructure.
~p~~~~Someinvestigatorshavesuggestedthattheoffshoreexploratorywell,Standard-Humbleffl(Fig.3),containsasectionofrocksthatismostlikethatonshoreatornearthesamelatitude(Santa'FeriaValley).Theoff-shorewellencounteredthefollowingsection:topoftheSisquocat3402ft(thickness635mor2082ft);topMontereyat5484ft(thickness358mor1176ft);topofvolcanicash(probablyObispo-Tranquillonvolcanics)at6660ft(thickness122m,or400ft);topof"volcanicrocks"(probablyLospe,personalcommunicationDavidHowell,1977)at7060ft(bottomofwellat7797ft).Onshore,atornearthesamelatitude,welldata(WoodringandBramlette,1950,crosssectionA-A')provideinformationtoshowthattheMontereyFo~~~~tionlieseitherontheLospeordirectlyonFranciscanrocks;whereasthewellprobablycontainsvolcanicash,'oftheObispoorTranquillonvolcanicrocks.ThesectionintheoffshorewellmightbestbecorrelatedonlandwithrockseithersouthoftheLompoc-Solvangfault(i.e.,nearPointArguel"o;seeDibblee,1950,geologicmap)orpossiblywitntheStandardOil"Sh~-.-ers":"-1southofPurisimaPoint(section4T.7S.,R.35W.),/herc.morethan32km(20miles)southofthewellontheopposite-sideofthetheS~gv~roSanSimeon-Hosgrifaultzone.ThepartiallogofwellshowninFigure1isprobablyincorrectandtheunitsencounteredwereprobably'IMontereyoverlyingObispo-Tranquillonvolcanics,whichinturnoverliestheLospeFormation.Thewellwasdrilledin1928and1929.Thus,theoffshorewellcouldeasilysupportbutdoesnotdetractfromthemodelofapull-apartbasinandoffsetalongtheSanSimeon-Hosgrifaultmeasuredintensofkilometers.ContinuousorrenewedlateTertiaryorQuaternarymovementmusthaveoccurredalongtheSanta>fariaRiverfault.Evidenceforthissuggestion isprovidedbythegeologyintheTwitchellDamquadrangle01all,1977)andthegeomorphologyandlateTertiaryandQuaternarygeologyalong*theFoxenCanyonfault(Fig.1).IntheTwi.tchellDamquadrangletheRestHuasnafaultfaultsQuaternarydepositsandisinturntruncatedby,oristhesameageas,theSantaMariaRiverfault.OTHERNEARBYREGIONALBASINSTheMorroBaybasintothenorthofSantaMariabasin(50kmnorthofSantaHaria)showssimilarrelationshipstothedevelopmentoftheSantaMariabasin.AlthoughthecorrelationofrocksatthemarginsoftheHorroBayTertiaryoasinisnotasclearasthoseatthe,marginsoftheSantaMaria-Lompocbasin,theHorroBaybasinmightalsorepresentapull-apartstructure.ThebasinmayhavebeguntoopenduringtheearlyOligoceneandthedacite-felsiterocksofthatage,formingHorroRockand12to13othermajorint~sivemassesinthe'area(includingtheCambriaFelsite),mayreflectaperiodofvolcanismandintrusionatdepthduringbasinopening.Sucha.interpretationwouldhavetoaccountforthefactthattheriftedintrusiverocksweredaciticandnotbasalticrocks.EquallyasspeculativeisthesuggestionthattheHorroRock-IslayHillcomplex(ErnstandHall,1974)wasrotated10to15degreestothewestafteremplacement,andthattheCambriaFelsiteinCambriaandatRockyButte'Hall,1973,1974,1975b;HallandCorbato,1967;HallandPrior,1975)
~.~werealignedwiththelforroRock-IslayHillcomplexatthetimeofemplacementduringtheOligocene.AnalternativeexplanationfortheHorroBaybasiniskthatitisanuplifted,tippedfaultwedgebasin(seeCrowell,1974)boundedbythePismoandHuasnainclinedsubsidencebasins.Suchasuggestiondoesnotprecludepre-midorlateMiocenecounterclockwiserotation.Ifthe'HorroBaybasinisanupliftedtippedbasin,itmusthavesubsidedduringlateliioceneorPliocenetimebecauseremnantsofrocksoftheseagesarepresentwithintheregionsboundedbytheEdna-LosOsosValleyandWestHuasnafaultsystems.ThesefaultsformthemarginsofthehlorroBaytippedfaultwedgebasin.Sb~MARYBasedonthegeology,stratigraphy,distributionofsedimentaryandvol-canicrocks,andlithologicsimilaritiesofwidelyseparatedrocktypes,thereisevidencetosupporttnehypothe'sisthattheSanta?4ria-Lompocbasinisapull-apartstructure.Thefault-boundedbasiniswedge-shapedwiththemaximumpull-apartbeingnearly50km.Thebasinmayhaveundergonerecurrentperiodsofr'ing,perhapsduringthedepositionoftheRinconShale,themostrecentofwhichtookplaceapproximately14m.y.'b.p-Thepresentlocationandorienta-tionoftheCretaceoustomiddleMiocenerocksintheWesternTransverseRangesareduetorightslipalongtheLompoc-Solvang-Santa?fariaRiver-LittlePinerightlateraltransform,subsequentcounter-clocLmiserotationorbendingoftheregion,andlateTertiaryand'QuaternaryleftslipalongtheSantaYnezfault.TOtherbasinsintheregion,e.g.PismoandHuasna,arepossiblytippedsub-sidencebasins(Crowell,1974)andtheMorroBaybasinisatippedfaultwedgebasin(Crowell,1974).Allstructuralbasinswereprobablyformedbetweenlargestrike-slipfaultsduringlatemiddleorlateHioceneandwereinpartlateraffectedbymovementalongsuchfaultsastheSanSimeon-Hosgrifaultaone 12andRinconda,Fault(Dibblee,1976).Therehasapparentlybeenat.least80orQoaa95kmofrightslipalongthe~L~~i~>~-~~>~<<~~ItsincethePliocene(duringthelast5m.y.)andfollowingtheformationoftheSantaMaria-Lompocpull-apartbasin.ACKNOWLEDGi1ENTSIwishtothankJ.C.Crowell,W.G.Ernst,W.R.Dickinson,andEliSilverfortheirhelpfulcommentsanddiscussionsoftheconceptsexpressedinthispaper.
.~REFERENCES13Crowell,J.C.,1974,OriginoflateCenozoi'cbasinsinsouthernCalifornia,inTectonicsandSedimentation,editedbyW.R.Dickinson:Soc.Econ.PaleontologistsandMineralogistsSpec.Paperno.22,pp.190-204.Dibblee,T.W.,Jr.,1950,GeologyofsouthwesternSantaBarbara'ounty,California:Calif.Div.MinesBull.150,pp.1-84,maps~Dibblee,T.W.,Jr.1976,TheRinconadaandrelatedfaultsintheSouthernCaliforniaCoastRanges,California,andtheirtec-tonicsignificance:U.S.GeologicalSurveyProfessionalPaper981,55p.Ernst,W.G.,andHall,C.A.,1974,GeologyandpetrologyofthekCambriaFelsite,anewOligoceneformation,west-centralCalif-orniaCoas"Ranges:Geol.Soc.AmericaBull.,v.85,pp.523-532.Hall,C.A.,Jr.,1975a,SanSimeon-HosgrifaultsystemcoastalCali-fornia:Economicandenvironmentalimplications:Science,v.190,pp.1291-1294.Hall,C.A.,Jr.1975b,GeologictfapoftheSanSimeon-PiedrasBlancasregion,SanLuisObispoCounty,California:U.S.GeologicalSurveyMisc.FieldStudiesMapMF784,scale1:24,000.Hall,C.A.,Jr.,1977,GeologicMapoftheTw>>4~ii><~>>"P~">~~k>~=~"""gdTePuSqaefPuadringlc>>SantaBarbaraCounty,California:U.S.GeologicalSurveyMisc.FieldStudiesMap,scaleof1:24,000(inpress).
'IReferencescontinuedHall,C.A.,Jr.andCorbato,C.E.,1967,Stratigraphy'ndstructureofMesozoicandCenozoicrocks,NipomoQuadrangle,SouthernCoastRanges,California:Geol.Soc.AmericaBull.,v.78,p.559-582.Hall,C.A.,Jr.andPrior,S.W.,1975,GeologicMapoftheCayucos-SanLuisObisporegion,SanLuisObispoCounty,California:U.S.GeologicalSurveyMisc.FieldStudiesMapkfF686,scale1:24,000Jennings,C.V.,1959,GeologicMapofCalifornia,OlafP.JenkinsEdition,Santa~fariaSheet.IJennings,C.H.andStrand.,R.G.,1969,GeologicMapofCalifornia,OlafP.JenkinsEdition,LosAngelesSheet.Turner,D.L.,1970,Potassium-argondatingofPacificCoastMioceneforaminiferalstages:Geol.Soc.AmericaSpec.Paper124,pp.91-129.Voodring,H.P.,andBramlette,M.N.,1950,GeologyandpaleontologyoftheSantaMariadistrict,California:U.S.GeologicalSurveyProf.Paper222,142pp.,maps.
WesternSantaAeofrockunitsYnezMountainsSantaMaria-LomocbasinCuyama-SantaMaria-SisuocRiversareaPliocenePlioceneMiocene-FlioceneMioceneMioceneMioceneOligocene-Miocene.OligoceneOligocene-SisquocFm.MontereyPm.L.Mont.I'm.TranquillonVolcanicsRinconShaleVaquerosSs.Sespe/AlegriaPormationsCareagaSandstonePoxenHudstoneSisquocI'in.MontereyI'm.Pt.SalPm.Sespe-LospeFormationsMontereyFm.Pt.SalPm.ObispoFm.RinconShaleVaquerosSs.SespePm.OligoceneEoceneCretaceous.JurassicCretaceous-JurassicorJurassicGaviotaPm.EocenerocksCretaceousrocksHondaFm.Franciscanrocks'Knoxville"Fm.PranciscanrocksorophioliteCretaceousrocksJurassicshaleFranciscanrocksTable1Generalizedpre-PleistocenestratigraphicsectionsfromthemarginsoftheLompocSantaMariabasin,westernSantaYnez.Mountains(Dibblee,1950),SantaMariaandLompocbasins(WoodringandBramlette,1950),andtheareanorthoftheSantaMariaRiver(Hall,1977),SantaBarbaraCounty,California.
"~FIGURECAPTIONS16LCIII'FIGUREl.Generalizedpaleogeologicmap(pre-MontereyFormationandgeneralizedstructurecontourmap.(baseofifontereyFormation),SanLuisObispoandSantaBarbaraCounties,California.GeneralizeddistributionofselectedstratigraphicunitsisfromJennings(1959),Hall(1977),.re-.donnaissance.geologicmappingintheSisquocandLompocareas,andfromcoreholedatasuppliedbytheCaliforniaDivisionofOilandGas,fromwelllogsSantaHariaDistrictOffice.Incompletewelldataareshown:i~lon-tereyFormation,Tm;PointSalFormation,Tps;"Temblor"Formation,,Tt;RinconShale,Tr;VaquerosSandstone,Tv;LospeFormation,Tl;Franciscanrocks,KJf;Jurassicshale,Jsh;Jurassicophiolite,Jo.A.Sylvester(Univ.Calif.,SantaBarbara)reports(personalcommuni-cation,1977)thepresenceofafaultinthevicinityofSantaYnez4.andSolvangwithanorthwesttrend.IbelievethatthisfaultisacontinuationozthePezzonifaultandpassesnearLosAlamos;-theexactlocation,however,isunknown;'IFIGURES2a-2e.Hypotheticalpaleogeologicmaps.UFigure2a.-HypotheticalpaleogeologicmapfollowingorduringthedepositionoftheGaviotaFormationofOligoceneage.CoastalpartofCalifornia.rFigure2b.-Hypotheticalpaleogeologicmap,followingstrike-slipalongtheLompoc-Solvang-LittlePinefaultandbeforethedepositionofthe7Sespe-Lospeformations.CoastalpartofCaliforniainthevicinityofwhatisnownorthwesternSantaBarbaraCounty.Theinitialtrendandamountofstrike-slipisnotknown.
Figure2c.-HypotheticalpaleogeologicmapfollowingdepositionoftheObispo-Tranquillonvolcanicrocks.FollowingdepositionoftheGa'viotaFormationandstrike-slipontheLompoc-Solvangfault,theSespe(andthemarineequivalentAlegria)(coarseswirleddots),Vaqueros(finerandomdots),RinconandObispo-Tranquillonrocks(finemixeddots)weresuccessively(northeast-southwesttrend)andunconformablydepositedupontheunderlyingFranciscan(F)(verticallyruled),Cretaceous(K)(horizontallyruled),Eocene(E)(nopattern),andsomeOligocene(0)(diagonallyruled)rocks.Figure2d.-HypotheticalpaleogeologicmapshowinggeologyofnorthwesternSantaBarbaraCountyapproximately14m.y.b.p.Basinpull-apartbegantodevelopalongtheLompoc-Solvang-LittlePinefaultcon-te-poraneouslywiththebirthoftheSantaMariaRiver-FoxenCanyon-LittlePinefaultzone.Vaqueros,Rincon,andvolcanicrocksareatthemarginsoftheopeningbasin,butareremoved,exceptforremnantsleftonthestretchedandtectonicallymixedFranciscant;rocks,fromthecenterofthebasin.Cretaceous,Eocene,andOligo-cenerocksalongwiththeoverlyingSespe,Vaqueros,RinconandObispo-TranquillonrocksaresouthwestoftheLompoc-Solvang-zoneLittlePinefault(diamonds);FranciscanandremnantsoftheSesperocksliebetweenthetwofaults,andCretaceous,Sespe,Vaqueros,Rincon,andObisporockslienortheastoftheSantahfariaRiver-FoxenCanyon-LittlePinefaultzone(triangles).Strike-slipprobablyaccompaniedthedevelopmentofthepull-apartbasin.
~'~~18Figure2e.-Generalizedpre-lateMiocene'paleogeologicmap.TheproposedmodelsuggeststhecounterclockwiserotationoftheLompoc-Solvang-LittlePinefault,rotationthathasoccurredsometimesincethelatemiddlepliocene.TheinferredLompoc-SolvangfaultintheproposedmodelisthenorthernboundaryofTransverseRangesinthewesternpartofSantaBarbaraCounty.FIGURE3..LocationoftheSanSimeon-Hosgrifaultz'one,SantaMariaRiver,Lompoc-Solvang,andotherfaults.,Spots(Ti~Tertiaryintrusive)indicatesitesofOligocenehypabyssalvolcanicrocks,includingtheiforroRock;IslayHillvolcanicrocksandsimilarrocksinthenorthnearRockyButte.LocationofStandard,OilCo.ofCalifornia-HumbleOilCo."Oceano81"isshownwestofSanSimeon-Hosgrifaultsystem.
PIIrisimoPoinlRjntArguelioGENERALIZEDPALEOGEOLOGICMAP'tPItEMOilTEREYI'ORMATIONlANDGENERAI.IZEDSTRUCTURECONTOURMAP(13ASEOFMONTEREYFORMATIONlSANLUISOBISPO-SAN'I'A13AR13ARACOUNTIES,CAI.IFOI~WIAOn/EXPIANATIONOara~Oll'-":I;Wa:IHaaaaafaallQGUAoALupECretaceousrocksf="..]VaquerosSandstone-JtFranciscanmelange-I-'-.:MRinconShoto.ophiolilecomplex4X<~P;)LB4/(lllPGETTERAVIA4Jo'I3OoooaIIEooi>>'oI."..'.-;:,';.'espe-LospeFormotionsSerpenlinileLimitofMontereyT~~EE~SantaMarioRiverfault0C~Oy0-505t0QORCUTT-.'0X~~ip/io~LimitofLospeFormotion,p/~~4/oCASMALIAI--X'e,'iiX~~~.:-:--In<<-Structurecontourline'EE0Cp,.4K=<iNeo'a~~fpu//--Fault~~~o-o->Lompoc-Solvangfaults6~QLOSALAMOS~(oKJtIa*Tmsrn(4nlV~4Exploratoryoilwellou//o~BOE+~ŽHaaaaIaa~+L,~~~OBUELLTOUOOOUTOTl,'EE+BBITBBEforllEp~Ex4ro/jr~EnE~Tao4f$onto)n-~~<u//-"-+4Q~(OIIO--~/GAVIOTAPASSfoulg50miles/15km.'aPoifltConeepifenPacificOcean
=CRITACEQUS'OCENEFRANCISCAROCKS1'llOLIGOCENElGAVIOTAlEOCENEOLIGOCENExfGAVIOTAl8/8/1zrgfllit'rer!ii:rrte'-'"::OBISPO-'.."':".",ir-"lt.TR.4iQLILLO<<,,',i'..',.-,*",.<<,,,;.'e',.";!"Y.;:-,.":,"::.;'t"~lljjtfCefe~e~,'e~IIK.:;,".':'OBISPO.:'.-'TRAhQUILLOtr-.rtfr[!tileSESl!~jm~~~e,jhT}PFrrt~ettreeejetetrlifjece~r'jtttSSEPijirf'::.',..'.:';,.":::e."!",,:;.'-',li,vAQUERQsglliGic':,".e:,t'.::~..:.;![it~$-l<!.~J!,RZ'.-CO'~l,IIlCf.)tttOaIS>.igll,lijff!e.ll!i~'!l,lljf,'-OBISPO--,THANQUILL'Oi-Rr~ro~",.'-',-""',j!-;-'SFRPEji~"-;...VAQUEROSI-20 I~~36o35o0CapeSonMartin'.~~~~ee~~~~~~~~~~~~~~~OCte)MorroBoy(0~ePt.SonLuis~eeI:.(q~C~~~pVp~p00Gg04/C0CDeeeArroyo6rondeSp0IL0+oOq.Santo4@~MorioPG010kilometersSantoMorio-LompocBasin~~~~~~~~~~~RoggedPt.~e~~~~~~~~~lPockyTj(dpt.PiedrosBlancosSanSimeonSonSimeonPt.PosoRobicsDc'.+CambrioOilOGPt.Buch~~~ee~~~e~~p~ee~ee~~~~ee'ee~W~~~~~~~~~~Stondard-.Humble.+'-.OceanoNl'e0:.~Pt.SallQmilesHeod~~PurisimoPt.MapLocation~~~~~e~e~~~Lompoc~7~~PbAruello~eeee~ee~e~eeee~ee~e~ePt.Conception:,~e2lo
~'
II~~IATTAC11MENTJ~~MARINEGEOLOGYANDTECTONICHISTORYOFTHECENTRALCALXFORNIACONTINENTALMARGINEliA.Silver2DavidS.McCulloch3JosephR.Curray4SantaCruz,CaliforniaMenloPark,CaliforniaLaJolla,CaliforniaABSTRACTThegeologyofthecentralCaliforniacontinentalmarginshowsahistoryofearlyTertiarysubductionoftheFarallonplatekandfollowedbyaMioceneandyoungerperiodofhighanglefaultingandbasinformationcorrespondingtotransformmovementbetweenthePacificandNorthAmericanplates.Seismicreflectionprofilesshowirregularstructuralsurfacesontheoldersedi-mentaryrocks,whichareoverlain-bymildlywarpedyoungerstrata.'argeshelfbasins,includingthe.SantaMaria,Sur,OuterSantaCruz,Bodega,andPt.Arenabasins,areboundedbydown-to-basinfaults.Thestructuralstyleofmost'fthesebasinsissimilar,althoughthePt.Arena,OuterSantaCruz,SantaMariaandSurbasinsprobablyrestonFranciscanbasementandtheBodegaliesongraniticbasement.Drillingdatasuggest.anearlysynchronousoriginforthesebasinsin'middleMiocenetime(HoskinsandGriffiths,1971).Analysisofpi..esentlyavailabledataforthehistoryoffiniteplatemovementssincethemiddleCenozoicsuggestsawestwardshiftinthedirection ofmovementofthePacificplaterelativetotheNorthAmericanplateinthisregionabout10millionyearsago(m.y.a.).Suchachangeinplatemotioncouldhaveprovidedasufficientextensionalcomponentofmovementtoresultinbasinformation,possiblyalongtheolderstructuralgrainofthemargin.SomeoftheQuaternaryfaultingishighanglereverseinsense,indicatingacompressionalcomponentactingoverapproximatelythelastmillionyears.ltispossiblethattheinstantaneousmovementbetweenthePacificandNorthAmericanplateshasbeenchangingcontinuallyduringthepast30m.y.ThedistributionofgraniticrocksoftheSalinianblockonthecontinentalmarginconstra'insmeasurementsofoffsetalongtheSanAndreasandSanGregoriofaults.TheSanAndreassystemoffaultsshowsatleast550kmandamaximumof600kmoffset,basedonthenorthernextentofgraniticbasementunder-lyingFarallonridge.TheSanGregoriofaulthasanestimatedoffsetof100+15km,basedonoffsetofthesouthernendofFarallonridge.TheseobservationssupporttheideaofsliveringwithintheSalinianblock(JohnsonandNormark,.'1974).However,earlyTertiarypaleogeographicreconstructionsbyNilsenandClarke(1975)requiresomeSalinianoffsetbyearlyPaleocene,incontrasttothemodelofJohnsonandNomark.Wefavorapproxi-mately100kmofoffsetduringlatestCretaceoustoPaleocenetimeand450to500kmoffsetafter22m.y.a.GraniticbouldersdredgedfromSantaLuciaBank,farwestoftheSalinianblock,raisethequestionofeitherthepresenceofgraniticfaultsliceswestofJ-2
~~I~1theSalinianblockorextenivetransportofthesebouldersfromSaliniansourceareas.
ManuscriptReceivedAccepted2.UniversityofCalifornia,SantaCruz,California950643.U.S.GeologicalSurvey,MenloPark,CA940254.-ScrippsXnstitutionofOceanography,LaJolla,CA92093WethankW.R.NormarkandH.C.Wagnerforcarefulreviewsandsuggestions.D.G.Moore,R.vonHueneandH.G.Green'egenerouslyallowed,useofunpublishedreflectionprofiles,andtheNationalOceanSurveygenerouslyalloweduseofunpublishedgravityandmagneticdata.WearegratefultoT;C.Worsleyforpaleonto-logicanalysis,toL.Silver,E.C.BeutnerandL.Leefoxpetrologicexaminationofsomeoftherockscollected,andtoC.McHendrieandRobertBruneforagreatdealofeffortinprovidingcomputeroutputofmuchofthedata.Wearegratefulfordiscussionswithandideasfrom,C.G.Chase,T.Atwater,S.A.Graham,W.R.Dickinson,W.Gawthrop,C.H.Hall,D.Hamilton,J.Crouch,E.C.Bcutner,J.C.Crowell,T.Nilsen,andtoagreatJ'anypeople,toonumeroustomentionortoproperlyrecall,whocontributedtothi+workinverysignificantways.Ourlackofcitationhereisnotthroughlackofgratitudeorindebtedness.Wefinallythankthecaptains,crewsandscientificpartiesofmanyexpeditionstotherollingseasoffcentralCalifor'niafortheircooperationandsupport.
INTRODUCTIONThecontinentalmarginoffCentralCalifornia,betweentheMendocinoandMurrayfracturezones,hasundergoneacomplextectonicdevelopmentduringCenozoictime.Atwater(1970)hasinterpretedthemagneticanomalypatterninthenortheastPacifictoimplysubductionoftheFarallonplate(McI(enzieandMorgan,1969)beneaththemarginintheearlyTertiary.Approximately30m.y.a.subductionbegantoceasealongCentralCaliforniaandstrikeslipfaultingsubsequentlybeganalongthemargin.IThesetectonicprocessesprobablyplayedamajorroleindevelop-ingthestructureofthemargin.ThepresentstudydescribesthatstructureandevaluateshypothesesfortheCenozoictectonic,.evolutionofthecontinentalmargin.Geophysicalstudyofthemarginhasincludedsinglechannelseismicreflectionprofiling,utilizinghighandlowenergysoundsources,onapproximatelynineexpeditionsoftheScrippsInstitu-tionofOceanography'ndoftheU.S.GeologicalSurveysince1964(Fig.1).AdditionaldetailedstudiesareavailableforMonterey.Bay(Greene,1970),atPointArena(unpublishedPacificGasandElectricCompanyreport)andbetweenPointArguelloandPointSur(McCullochandothers,1977;Buchanan-Banksandothers,1978).GravityandmagneticdatawereobtainedbetweenSanFranciscoandPointArguelloandmagneticdatanorthtoCapeMendocino.Wewerefortunatetohaveaccesstoanextensivegravity,magneticandbathymetricsurveydonein1970bytheNationalOceanSurvey.
Sea.floorrockswereobtainedbydredging(Fig.1)onAntipodeandSeven-TowexpeditionsoftheScrippsXnstitution,onseveralU.S.G.S.expeditionsoftheR/VKelezandR/VBartlettandfrompreviousworkers(Hanna,1952;UchupiandEmery,1963;MartinandEmery,1967).HoskinsandGriffiths(1971)-hereafter~abbreviatedas(H-G)-publishedstructuralinterpretationsofshelfbasinsbasedonShellOilCompanyseismicprofiles,dartcores,andwelldata.Thedatawerenotavailabletous,butwehaveusedtheirpublishedmapsandcrosssectionsforagecontrolwheneverpossible.Forconvenienceof'resentationofthegeophysicalresultsandstructuralinterpretationwedividetheCentralCaliforniacontinentalmarginintothreeregions:1)PointArguellotoMonterey(34to36.5'N);2)MontereytoPt.Reyes(36.5to38'N);3)Pt.ReyestoCapeMendocino(38to40.5'N).GEOPHYSICALRESULTSPointArugellotoMontereyThedominantstructuralfeaturesofthispartoftheconti-nentalmargin'aretheSantaLuciabankandtheSantaMariaandSurbasins(Fig.2).ThebankisabroadhighboundedontheGastbytheSantaLuciabankfault(Figs.2and-3)andonthewestbythetopofthecontinentalslope(seeprofiles16-28,Fig.4).TheSantaMariabasinoffshoreliesbetweentheHosgriandSantaLuciabankfaults(Fig.2).TheSurbasiniscontinuous
~li~~hwiththeSantaMaria,isboundedbycoastal'faultsontheeast(Fig.3),andsedimentthinswestwardagainstthenorthernpartofSantaLuciabank(Fig.5,'2-L10)..ThebasinsandbankmakeuptheArguelloPlateau(UchupiandEmery,1963).Thestructuraldevelopmentoftheregionwasdiscernedfromthegeo-physicaldata,butthetimingoftectoniceventsreliesondatafromthegeologyoftheonshoreSantaMariabasin,offshoredrillingbyoilcompanies(H-G),anddredging.TheSurbasin(Figs.2,3)iscrossedbyprofilesL2-L10(Fig.5,)andhasgreatestsedimentthicknessinprofileL6.Theedimentthickenseastward,withmorethan.threekilometersofsedimentverynearthecoast.Theshelfisnarrowhere,andisprobablyboundedontheeastbyafault.ThefaultissuggestedbytheverticaloffsetinFranciscanrockthatprobablyunderlietheSurbasinoffshore,andareexposedalongthecoastline,anoffsetofatleastfourkilometers.Thefaultisalsosuggetedbyasteepgravitygradient(Fig.6).Thenearabsenceofdeformationinthesebasinstrata,andtheeaseofacousticpenetrationsuggeststhatthelayeredsectiononlineL6islargelyoflateCenozoicage.H-G(1971)interpretthebaseofthelayeredsectiontobelowerMiocene.Anuncon-formityoccurswithinthesectioninlineL2'(Fig.5)butitsageisnotknown.TheSantaMariabasinisdevelopedonlinesL12toL20,andinmanyprofilessedimentthicknessisgreatestateitheredgeofthebasin(seelinesL16,L18,L22,L24,L26),assedimentwedgesthickentowardandterminateagainstthefaultsthat Nboundthebasin.AtleasttwounconformitiesareseeninlinesL14toL28,especiallywelldisplayedinlinesL16andL20(Fig.4).ThelowerunconformityprobablyseparatesMioceneandyoungerrocksfrompre-Miocenerocks.TheupperunconformitymaybelateMioceneorPliocene.AnunconformityseparatingearlyTertiaryfromlateCenozoic(undated)rocksisbeautifullydisplayedonlinesL20,L22andL24.TheSantaLuciabankfaultformsthewesternboundaryofthebasinforabout150km.ThefaulthasitsgreatestphysiographicexpressioninlineL20(Fig.4)wherethe'seafloorisoffsetabout150m.Tothesouththefault,nearlyintersectsawesttrendingfaultthatboundsthenorthsideofthechannelislandsplatform(Fig.3).However,therelationbetvreenthesefaultsisnotclear.TheeastsideofthebasinisboundedbytheHosgrifault'Nagner,1974),whichcanberecognizedasamajor*basementoffsetontheinnerpartsoflinesL16toL26.Shallowwaterdepthsandringingmultiplereflectionsinsomeprofilesact.toobscurethestructure.TheHosgrifaultisprobablyseismicallyactive.Anearthquakeofmagnitude7.3occurredinthevicinityofsouthernSantaMariabasinin1927,andByerly(1930)reportsthatatsunamioccurredalongthecoastofsouthernCaliforniafollowingtheearthquake.Recentrelocationstudies(Gawthrop,1977)placethe1927epicenteratthesouthernendoftheHosgrifault.TheHosgrifaulttrendsnorthwardtowardtheSanSimeonfaultonlandandisprobablycontinuouswithit.Hall.(1976)presentsevidenceforrightlateraloffsetof80kmto100kmbymatching1 geologicsectionsatSanSimeonwestofthefaultandPt.Sal,80kmsouthandontheeastsideoftheIIosgrifault.ThesectionisJurassicthroughPlioceneandrestsonJurassicophiolite(Hopsonandothers,1973).TheexactlocationandbehavioroftheHosgrifaultbetweenSanSimeonandPointSurisuncertain,butthefaultisprobablycontinuousandmaycontinuenorthtoorbeen-echelonwiththeSanGregoriofault,describedbelow.BasementrocksappeartodirectlyunderlieupperCenozoicdepositsinthecentralpartoftheSantaMariabasin.ProfilesL16andL18showanarchedbasementreflectorwhichcorrespondwithagravityhighandmagneticanomaliesofupto200nT(Fig.7).AcrustalmodelfittedtogravitydataonlineL18issatisfiedbyahighdensity(2.85gm/ccinthismodel)blockinthecentralpartofthebasin(Fig.8).ShallowbasementbeneaththebasinisindicatedbypairedmagneticanomaliesthatareelongatedparalleltothebasinbutconfinedbetweentheHosgriandSantaLuciabankfaults(Fig.7).Thewesternanomalyispositive(>100nT)andtheeasternisnegative(>-100nT).Thenegativemagneticanomalycoincideswiththehighdensityblockandmayb'ecausedbybasalticx'ocksoftheFranciscanassemblage-perhapspartofthePt.Salophio-litedescribedbyHopsonandothers(1973).Itnowappearscriticaltodrillthesectionoverthisreflectortoseewhetherit.issimilaroxdifferent.fromthesectionsmatchedbyHallacrosstheHosgri-SanSimeonfaultasatestofwhetherthosesectionsaretrulyoffset80kmorhavecontinuityoffshore.\I~4~~
~~JusteastoftheHosgrifaultisaseriesofNW-trendingfaultsthatstrikeintotheHosgriatananglebutdonotcut,thelargefault.Someofthesesmallfaultspossiblycut.Holocenesediments(Wagner,1974),suggestingthatbothfaulttrendsmaybeactive.TheageoftheSantaMariabasinisreportedtobelatemiddleMioceneonthebasisofdrillingbyShellOilCompany(H-G).ThisagedatestherelativeupliftofSantaLuciabankonthewesternmarginofthebasin.WoodringandBramlette(1950)'eport.thatmarinedepositioninthepresentonshorepartofthebasinbegaininthemiddleMiocenewiththePt.Salformation.MarineconditionscontinuedtherethroughPliocenetimeandmajordeforma-tionoccurredinthePleistocene.LocalcompressionaldeformationisseeninSantaMariabasinoffshore.Figure9(profileLDMinFig.1)showsalargefoldofsedimentaryrockbuttressedagainstabasement.blockonitseastside.Thestructuremayhaveresultedfromlocalshearbetweenbasementrocks.SantaLuciabankformsasmoothtopographicsurfacebuthasacomplexinternalstructure.TheblockfaultedstyleofthebankledH-Gtopostulaterigidgraniticbasementatdepth.Seismicprofiles(Fig.4,L20toL28),however,showacomplexlydeformedinternalstructurewithinthebank,suggestinganearlierphaseofdeformationthatwasneitherrigidnorblocklike.Thusthebankhasundergoneatleasttwodistinctlydifferentstylesofdeformation.
Theolderfoldingdeformationofthebankistruncatedbyanerosionalunconformity,andinsomelines(Pig.4,L20andL24)theblockfaultingpot-datestheunconformity.If,asdiscussedbelow,graniticrocksarepresentbeneaththebank,theyaremorelikelypxesentassmallfaultslidesthanasacontinuous,rigidmass.Ourprofilesdonotshowacontinuousacousticbasementbeneaththebank.Threedredgehauls,D4,D5'ndD7,weretakenonthebank.Dredgehaul(D5)wastakenonafaultedoutcropontheeastsideofSantaLuciabank,crossedbyprofileL26(Fig.4).Thislatterdredgerecoveredwellroundedbouldersandcobblesindica-tiveofsignificanttransportpriortodeposition,andalsosomerockfragments,assumedtobelocalbedrock.'hemostabundanttransportedbouldersweremeta-conglomerate,meta-sandstonegargillite,andmaficvolcanicrocks.In-placerocksincludedpholad-boredgraniticsandstoneandcalcarenite,chert,andonepieceofactinoliteschist.Theschistwasveryangularand'Ieasilybrokenandprobablycouldnothavesurvivedappieciabletransportation.DavidMoore(pexsonalcommun.,1971)dredgedglaucophaneschistveryneaxthislocation.Dredge4,locatedonlineL16(Figs.1and4),recoveredseveralroundedcobblesofquartzmonzoniteandquartzdiorite.Themostcommonrocktyperecoveredwasgraniticsandstone,withlesseramountsofpholad-boredphosphorite,somesiltstone,andmaficvolcanicrock.Thesandstone,siltstone,andphosphoriteweremostprobablyinplace.Thegraniticcobbles,weretransportedanunknowndistance.IndredgeD7,locatedonprofileL28(Figs.1and4),softgranitic sandstonewasthedominantrocktyperecovered.Thesizeand'ngularityofthegraniticsandstoneindicatethatitwasinplace.individualgrainsareangulartosubangular,implyingrapiddepositionwithlittlereworking.Quartzandfeldsparcommonlyshowundulatoryextinction,andthemicasaredeformed,.suggestingthattherockhasundergoneasignificantshearingorflatteningdeformation.ThesandstoneissimilartothatfoundwithintheFranciscanassemblage,whichalsoisquartzrich,angulartosubangular,andinternallysheared(Baileyandothers,1964).Thegraniticcobblesandsandstonecouldhavehadeitheralocal(favoredbyH-G)oradistantsource.Localsourcebodiescouldbeeitherintrusionsorfaultslivers.'Distant.sourcescouldbefromtheSalinianblock(generallyconsideredtobeanoffsetsliceofSierraNevadagranitic-metamorphicbasement,boundedby.theSanAndreasandSur-Nacimientofaults).Atthebaseofthecontinentalslope,allprofilesshowabasinwith2kmormoreofsedimentfill.Profiles16;20,22and28showabasement,reflectorpassingbelowthelowerpartofthecontinentalslope.XnlineL20,basinstrataoverlapcontinentalslopedebris..ThesamerelationsoccurinlineL28,buthereseveralhundredmetersofstrataabovethebasementreflectorpassundertheslopedebris.lnlineL22thestructureispartlyobscuredbyasmallfaultblockatthebaseoftheslope.Theseobservationssuggestthatnotectonicdislocationhasoccurredalongthelowerpartofthecontinentalslopeduringdepositionoftheuppertwothirdsofthebasinsediment.
~~Aninactive,northwest-trendingfracturezoneoffsetsmag-neticanomalies,questioninglyidentifiedasanomalies7and8,approximately30m.y.oldbyAtwater(1970).Thefracturezoneismarkedbyaridgethatprovidesfurtherevidenceforthe"stabilityofthelowersloperegion'(Figs.3;4,linesL18,L20,L22,andL24;Fig.7).TheridgeextendsontothelowerpartofthecontinentalslopeinlineL24,anddredgingatthislocationyieldeddominantlyfine-grainedolivinebasaltandmanganesenodules.These.rocks(D6,Figs.1and4)arequiteunlikeallotherstakenonthismarginandareclearlyrepresentativeofaseamountorvolcanicridge.Thedredgesamplesindicatethatthefracturezoneridgeextendstothecontinentalslope.Noappreciablelateraloffsethasoccurredbetweenthevol-canicridgeontheslopeandtheoffshorefractureridgeifthiscorrelationismeaningful.Theageoftheridgecanbenoolderthantheseaflooroneitherside(about25to30m.y.).1ftheridgeformedclosetothetimeofseafloordevelopment,themostprobablecase,thenlittleornolateraloffsethasoccurredalongtheSantaLuciaescarpmentsincethePacificandAmericanplatescameintocontactinthemiddleTertiary(Atwater,1970;McKenzieandMorgan,1969).MontereytoPt.ReyesThedominantstructuralfeatureoftheMontereyBayareaistheSanGregoriofault(H-G,1971;Greeneandothers,1973)whichcanbefollowednorthwardandoffshorefromAnoNuevoPointtointersecttheSanAndreasfaultsystemoffSanFrancisco, givingameasuredlengthof150kmfromsouthofMontereytoSanFrancisco.TheSanGregoriofaultprobablyseparatesgraniticbasementrocksontheeastinMontereyBayfromnon-graniticrockstothewest(MartinandEmery,1967;Greeneandothers,1973).Eastofthefaultisaseriesofnorthwest-trending.faultsthatdonotcrosstheSanGregoriofadult.EarthquakestudiesshowthatboththeseNNtrendingfaultsandtheSanGregoriofaultareseismicallyactiveandfirstmotionstudiesshowthatbothareundergoingrightslip(Greeneandothers,1973).ThispatternisstrikinglysimilartothatdevelopedeastoftheHosgrifault(Wagner,1974;Gawthrop,1977).Furthermore,theSanGregoriofaultmaybethenorthwardcontinuationoftheHosgri-SanSimeonfaultzonedescribedabove.Xfthissuggestedcontinuityisprovedcorrect,theaggregatelengthoftheSanGregorio-Hosgrifaultzoneapproaches400km.TheSanGregorioappearstooffsetgraniticbasementterranesatleast90km(Silver,1974)andMioceneandolderrocksasmuchas90to115km(Graham,1976;GrahamandDickinson,1977).TheIsuggestedoffsetoftheSanGregoriofaultis,withinthelimitsoferror,equaltothesuggestedoffsetoftheHosgrifault,greatlyincreasingtheprobabilitythat.theyrepresentasingle,continuousfaultzone.Tworidgesandtwobasinsliewest,andnorthwestofSantaCruz.'heFarallonridgeiscomposedofquartzdioriteattheFarallonislandsandappearstointersectthecoastnorthofAnoNuevoPoint.TheridgecanbetracedcontinuouslyinseismicprofilesasfarnorthasPointArena(Fig.2),andshowsclearly 15asahighonthegravitymap(Fig.6).Thefree-airanomalyreaches50mgalnorthofthoFarallonislandsanddropstonearlyzerosouthwestofHalfMoonBay.Thisgravitylowalongthe'idgemaymarkanolderosionalortectonicnotch.Apronouncedpositivemagneticanomalyismappedoverthesouthernpartoftheridge(~ig.7).ThenorthwardextensionofthismagnetichighalongtheFarallonridgeislessintenseandcannotbecontouredbecauetheavailableprofilesaredominatedbyrelativelystrong,andasyetuncorrectedeffectsofdiurnalvariation.Themagnetichighcanberecognizedfromprofiletoprofile,however.ThegravityanomalyismostpronouncedwestofSanFranciscoandPt.Reyeswherethemagneticanomalyisleastdeveloped.Theridgeasstructurallydefineddoesnotrepresentsimplythesurfaceexpressionofgraniticbasement.Forexample,lineN23(Fig.10)showsgraniticrockbetweentwofaultsontheuppercontinentalslope.TherestoftheridgeinthisprofileisunderlainbyupliftedsedimentsofMioceneandyoungerage,'ndUpperCretaceoussedimentaryrocks,whichprobablyappearasacousticbasementinourreflectionprofiles,cropoutnorthofAnoNuevowheretheridgeappearstointorsectthecoast.EastofthisridgetheBodegabasinlocallycontainsmorethan2kmoflateCenozoicsediment.Theeastmarginofthebasinisformedbyhighanglereversefaults,fromthePt.ReyesfaultonthenorthtoanarrowfaultzoneoffHalfMoonBay.ProfilesK44andK66(Fig.11)showaburiedunconformity,belowwhichsedimentsarofaultedandmoretightlyfoldedthanthepostuncon-formitystrata.ComparingourprofileswiththeH-Gdrillingages, theunconformityismiddleMiocene.AnH-GcrosssectionsouthwestfromBodegaHeadshowsthin'lowertomiddleMiocenestrataoverthecentralpartofthebasinwithwestwardthickening.ThisstructureindicatesthatthecentralpartofBodegabasinstoodhighinthelowerandmiddleMiocene.Upliftofthewesternmargin(theFarallonridge)andsubsidenceofthebasin.commencedinaboutthelatemiddleMiocene.TheSantaCruzhighliesoffSantaCruzandsouthwestoftheFarallonridge,andbetweenthetworidgesliesOuterSantaCruzbasin(Fig.2).BoththeSantaCruzhighandouterbasinplungenorthwest(linesSl-3,Fig.12).TothenorththehighdiminishesandthewesternmarginofthebasinisformedbyPioneerandGuideseamounts.Adredgehaulandcore(AD21andACDll}recoveredmaficvolcanicrockfromtheSantaCruzhigh.OuterSantaCruzbasinattainsathicknessofatleast3km.Thelowerlayersonthewestsideofthebasinaregentlyup-turnedagainsttheSantaCruzhighinlineS2(Fig.12),buttheAupper1kmofsectionabutstheridgewithnosignofdistortion.ProbablynoverticalmovementoftheridgehasoccurredinQuaternaryorlatePliocenetime,basedonestimatedsedimentagesinseismicprofiles,butearlierupliftisindicated.Theeasternmarginof,thebasinappearsfaultcontrolled(seelinesK68,K93,andS1-4)butfaultingaffectsonlythedeeperlayersandprobablyhasnotbeenactivesincelateMiocenetime.Thisstructurecon-trastswiththebasinedgefaultsboundingBodega,SantaMariaandSurbasins,whichshowPleistoceneandinsomecasesHolocene'ctivity.
DredgingonthecontinentalslopewestofFarallonridgehasyieldedrockandsedimentof.Mioceneandyoungerage(Hanna,1952;UchupiandEmery,1963;CurrayandSilver,1971;SilverandMcCulloch,1973,unpublisheddata)..Reflectionprofiles(Kl,K44,Fig.11)showMioceneandyoungerstratapassingsmoothlyacrossthecontinentalslopeoutontotheabyssalplain.Thesedimentsarecutbysubmarinecanyons,valleysandslumps,butshowlittleornosignoftectonicactivity.Insomeprofiles(Kl,K44,K66),coherentreflectionsbelowtheyounger,regularlybeddedsedimentblanketmaydenoteafoldedsedimentarysequencerepresentingatectonicenvironmentquitedifferentfromthepresentone.Someofthesedeep,irregularreflectionsareasso-ciatedwithvolcanicrocks(K93,Sl,S3),asinterpretedfrommarinemagneticanomalies.Atwater(1970)suggestedthatinearlyTertiarytimetheCentralCaliforniaareawasaregionofcrustalsubduction.WesuggestthatthefoldedsedimentarysequenceseenonthecontinentalslopeinlinesKl,K44,K66,W19,andlines'L-18toL28wasdeformedbysubductionandsediment.offscrapingintheearlyTertiaryepisode.SubductionappearstohaveceasedbeforeMiocenetimebecauseMioceneandyoungerstrataarenotdeformed.Pt.ReyestoCapeMendocinoHorthofPt.ReyestheBodegabasinisboundedonthewestbytheFarallonridge,whichisfaultedinthisregion,andontheeastbythePt.Reyesfault.ThePt.Reyesfaultappearsasasharpflexureintheseismicprofiles(seelineW23,Fig.10) andH-Gmapitasaneast-dippingreversefault.TheBodegabasininthisarearesemblestheSantaMariabasinoffshoreinthatbotharebounde'dbydown-to-basinfaults.AswiththeSantaMariabasin,theBodegaandOuterSantaCruzbasinsoriginatedinlatemiddleMiocenetime(H-G).Bo<<gabasinnarrowsnorthwardastheFarallonridgeapproachesthecoast.Threeacousticunitscanbedistinguished,withinBodegabasinwhichareseparatedbybasin-edgeunconformities(profileW23,Fig.10).Thelowermostunitismost.deformedandisprobablyupperMiocene,basedonsectionsbyH-G.Thereflectorswithinthisunitareparallel,demonstratingthatupliftofthe'basinmarginsorrelativesubsidenceofthebasinbeganinlatestMioceneorearlyPliocene.TheoverlyingPlio-Pleistocenebedsarelessdeformedandtheuppermostlayershowsnoevidenceoftiltingagainsttheridge.ApproximatelytwokilometersofPlioceneverticalrelativeupliftareindicatedfortheFarallonridge~GraniticrockscropoutasfarnorthasBodegaHeadwithintheSalinianblock.NograniticbasementisreportednorthofBodegawestoftheSanAndreasfault,buttheextentoftheFarallonridgemayindicatesuchbasementasfarnorthasPointArena.Theridgeappearsasablock-likeupliftinprofilesKlandK3(Fig.11),andinW19throughW26(Fig.10).FaultsboundoneorbothsidesoftheridgeintheseprofilesandstrataofthewestsideofBodegabasinareuplifted.InlinesW18,W17andN16,anunconformitytruncatesboththeridgeandthebasinstrata,andPleistocenedepositsprogradeacrossit.The
~~~~blockstructureoftheridgeisnotevidentintheseprofilesandtheuppersurfaceoftheridgeisnotahardreflector,asitisfarthersouth.Thus,theridgestructureextendsasfarnorthasPointArena,butgran'iticbasementisfollowedwithconfidenceonlytoapproximately38'30'N,or50kmsouthofPointArena.Itremainsuncertain,therefore,whethergraniticrockscontinueatdepthundertheridgetoPointArenaorar'Tabsentnorthof38'30'Nandsedimentaryrocksmakeupthebodyoftheridge.EvidencesuggestiveofoffshoregraniticbasementnorthofBodegawaspresentedbyWentworth(1968)intheGualalaareawhereheidentifiedcoarseclasticCretaceoussedimentsderivedfromthesouthwest.SuchrocksunderthenorthernpartoftheFarallonridgecouldprovidesuchasource.TheseaflooroffPointArenaisexceptionallycomplex.The,Farallonridgeendsoffshoreofthepoint,butitsnorthernterminusisnotwelldefined.TheSanAndreasfaultbendstoamorenortherlytrendnorthofPointArena,andnorthwestofthepoint'isaseriesofcomplexnorthwesttrendingfoldsandfaults(Fig.3)inlateCenozoicstrata.Thesestr'ataarepartofthePointArenabasinofH-G.Onthewestsideofthebasinabroad,lowstructuralridge,theOconostotaridgeincreasesinwidthnorthward.TheridgeisIseenunderlyingabroad,lowterracenearthebaseofthecon-tinentalslope(Fig.10).'ineWX(Fig.13)followstheridgecrestandshowstheirrcgularcomplexstructureoftheridgeunderlyingthefairlyuniformlayeringoflateCenozoicstrataabove.
The,basementrockofOconostotaridgecropsoutonthenorthflankofNoyoCanyon(Pig.10,lineW8)andadredgehaulatthislocationyieldedabundantgraywacke.Therockisweaklyfoliatedtohighlyshearedinthinsectionandshowschloritealterationofthegroundmas.Itispoorly'fossiliferousbutcontains"afewnon-diagnosticMid-EocenetoOligocenenanno-fossils"(T.R.Worsely,writtencommun.,1973).Site173ofleg18oftheDeepSeaDrillingProject(DSDP)wasdrilledonthewesternflankoftheridge.Thehole'pene-tratedacompletesectionofmarinestratafromPleistocenethroughlowerMioceneorupperOligocene(?)andterminatedinandesite(culm,vonHueneandothers,1973).ThereflectionprofilesshowthattheseMioceneandyoungerstratapasssmoothlyacrossthebaseofthecontinentalslopeanddrillingindicatesthatdepositionalconditionswerequietinthisareabacktotheearlyMiocene.RecoveryofdeformedearlyTertiarysedimentaryrockandofandesitefromOconostotaridgedemonstratessomeof'thelithologiccomplexityoftheridge.InlineW18(Fig.10)thewestflankofOconostotaridgenearthebaseoftheslopeabutstheacoustic'-basementreflectorbeneaththesedimentswestoftheridgeandsuggeststhatthecontactbetweenpre-Miocenecontinentalslopematerialandtheoceaniccrustwastectonic.TheseobservationsimplythattheOconostotaridgewasformedundertectonicconditions'thathavenotbeenactivesincetheearlyMiocene.J-20
'ThePointArenabasinasdescribedbyH-G,isboundedbytheSanAndroasfaultontheeast,PointArenatothesouth,theMendocinofaulttothenorth,butisilldefinedonitswcternmargin.>leconsidertheOconostotaridgetoformthewesternmargin.Thestructureofthisbasinchangesmarkedlyfromsouth'henorth.profileN13(Fig.10)offPointArenahowsasectionofdeQrmeddepositsofprobableMioceneagecoveringmuchofthe;...rgin.Thismaterialisoverlainuncon-formablyintheheifadupperslopeareabyprogradinglatestCenozoicdeposits.U.-,dertheshelftheunconformitydipsuniformlyeastwardtolocation-whereitappearstoterminateagainst,afaultwithsignifica."."verticaloffset-ZnlineNllfol=-=Miocenerocksaretruncatedbyanunconformitywhichisin--.folded.'I(Fig.10,lineNll,'o20km)Beneaththeshelfedgeis,abasinwiththickdepositsabovethemityH-Gr:=-==aultswith.severalkilometersofverticaloffs<<oneithersid=--=thisbasin.ThebasinisseenonprofilesN9th'roughN12.The-=~logyeastofthebasiniscomplexandob<<redbymultiple--=lectionsontheseismicrecords.Theupporunconformityp'==avewidespreadextentthroughouttheeastern<<geofthe'==-==~andcropsoutorsubcropsatdepthsbetweenoneandtwo.'c=-..eterbelowsealevel.Xfthisinconformitresul<<dfromerosio-.=-;waveaction,uptotwokilometersofsubsidencesu~~<<nceoftheea~==->marginofpoint~renabasinmaybeinferredforguatern=--.-"ime.~"ottomreflee---sareapproximatelyparalleltotheeeaa"<<fOconos---=ridgeandminorfaulting(lineN8,Fig.10) occurs.Profilesfarthernorth,WlthroughW7,showminor'.deformationoflateCenozoicdepositsbutolderrocksareintern-allydeformed(lineNX,Fig.13).Thesurfaceoftheolderrocksisirregular,andunliketheyoungersediment,shownoobviousrelationtoerosionalchanneling.AnumberofrelativelytightfoldsandassociatedfaultsItrendnorthwestfromPointArenaanddieoutapproximately50kmtothenorth,wherethecontinentalslopebecomesmoregentle.'majorpartofthedeformationinthisarea,includingthelargeshelf-edgebasin,thefoldedunconformity,andfaultsoflargeverticaloffset,aremost,likelycontrolled-bytectonicprocesses,althoughsomedeformationmayberelatedtodownslopemovementofsedimentundertheinfluenceofgravity.TheSanAndreasFaultZoneTheSanAndreasfaultchangesorientationnorthofPointArenatoa'orenortherly-trendandcanbetracedonshorejustsouthofPointDelgada(CurrayandMason,1967).SouthofShelterCovesixprofiles(4notshowninFig.1)crosstheSanAndreas,whichoffsetstheseafloorwiththewestsideup,producingashorewardfacingscarp.Anotherfault,twomileseasthasnoseaflooroffset.ThemaximumobservedverticaloffsetontheSanAndreasfaultscarpoff-shoreis8m,andthereliefdecreasessouthward.ThegeneraldisplacementhistoryoftheSanAndreasisrightlateralslip,andsuchmovementwouldhaveproducedeast-side-upoffsetsincetheseafloorslopessouthwardalongthestrikeofthefault.Thereforetheobservedwest-side-uptopographicoffsetmustbeduetoverticalmovement.J-22 23'NorthofPointDelgadathelocationandcharacteroftheSanAndreasisunknown.'Nason(1968)mappedanumberofshearzoneson,landbetweenPointDelgadaandCapeMendocinobuthecouldfindnoevidenceforrecentmovementonthezone"nearPointDelgata.Un-fortunately,thecleargeomorphicevidencefor1906faultingatPt.Delgadacannotbetracedacrossthisarea(Lawson,1908).Thislackofevidencemaybetheresultofobliterationofsuchevidencebyextensivelandslidingandmasssoilmovementthatoccurinthisarea;orperhaps,theSanAndreasdoesnotextendonshorenorthofPointrDelgadaasawell-definedfault.Xnthisregard,BeutnerandHansen(1975)carefullyexaminedthestructureofthelargeinlandshearzonesanddeterminedaleft..lateralsenseofshearing,associatedwithlateTertiarysubduction.Theyalsofound,however,thatNN-trendingstructuresjustalongthecoastlineshowedevidenceforrightlateralshear.DetailedreflectionsurveysthatwehavemadeoffshorebetweenPointDelgadaandCapeMendocino(notshowninFig.1)havenodis-covereddefiniteevidenceoffaultingoffshorebetweenCapeMendocinoandPointDelgado.Numerousacoustic'irregularitiesonthenearshoreprofilesmayrepresentfaulting,butthedeeperstructureisobscuredbymultiplereflections.Noneoftheseirregularitiescanbetracedbetweenprofiles.ZftheSanAndreasfaultisexpressedbyasingletracenorthofPointDelgadaitmayrunalongthebeach.Seeberandothers(1970)showaverycomplexpatternofmicxoseismicactivityinthisregion.ThenorthwardbendoftheSanAndroaspresentsaninterestinggeometricalpuzzle.Afault-fault-trenchtriplejunctionliketheJ-23 24I~Mendocinoisunstableunlessonefaultisonastraightlinewiththetrench(subductionzone)(Fig.14).TheMendocinoshouldbeunstablebecausetheSanAndreasfaultandthesubductionzonearenotaligned.However,northofPointArenatheSanAndreasbendsnorthwardandthen,atPointDelgada,northwestward.Thisbendingraisesaseriousprobleminthatthenortherlytrend,betweenPointArenaandPointDelgada,shouldbeassociatedwithextensionacrossthe.fault,asindicatedinFigure14d..Possiblysubsidenceofthecontinentalmargininthisarea,asseenbydeepunconformities,agentlecontinentalslope,andanarrowshelfisamanifestationofextension.However,insteadofchangingthegeometryofthetriplejunctiontoacquireanewstabilityconfiguration(asin14c),theplateboundaries.appearto1beadjustingtomaintainstabilityoftheoldergeo'metry.TECTONXCDEVELOPMENTOFTHECONTINENTALMARGINThestrueturaldevelopmentofthecontinentalmarginofCentralCaliforniaprovidesimportant:constraintsforany.scenarioofthetectonicevolutionofthewesternUnitedStates.ThestructureofthelowerpartofthecontinentalslopeinthisregionshowswelllayeredMioceneandyounger'tratasmoothlycoveringanirregular,hummocky"basement"thatisatleastinpart,composedofdeformedPaleogenesedimentaryandvolcanicrocks.ThisstructuralsuperpositionisinterpretedtoindicatePaleogenedeformation,probablyrelatedtosubductionoftheFarallonplate(Atwater,1970),followedbyMiocenetoHolocene i~g~~rCtectonicquiescencealongthelowerpartofthecontinentalslope,EvidenceforMioceneandyoungerquiescenceisprovidedbythepresenceofavolcanicridgealonganearlyPliocenetransformfault(Fig.3)thatextendsundeformedfromtheoceaniccrustontothecontinentalslopewestofSantaLuciabank.Becausetheridgeshowsnooffetatitsjunctionwiththeslope,nosignificantMioceneoryoungershearcanhaveoccurredonthelowerpartoftheslopeifthiscorrelationiscorrect.Incontrast,abundantevidenceisseenforextensivefaulting,bothhorizontalandvertical,alongthecentralandinnerpartsofthecontinentalmargin.AnimportantstructuralfeaturefordecipheringtectonicmovementsinthisregionistheFaxallonridge.ThegraniticintrusivesalongtheoffshoreridgeindicatethatitistheprobableoffshoreextensionoftheSalinianblock,thesliverofgraniticandmetamorphicbasementlyingbetweentheSanAndreasandSur-Nacimientofaultzones(Page,1970).TheSalinianblockisgenerallyinterpretedasasliceofSierran-typebasementthathasbeendisplacednorthwestward'longtheSanAndreasfaultsystem(Efamilton,1969;Page,1970;Crowell,19G2)althoughalternativehypotheseshavebeensuggested(kIsu,1971).Ifthefirsthypothesisiscorrect,thenthenorthernextentofgraniticbasementrocksrecordsthetotalhorizontaloffsetalongtheSanAndreasfaultsystem.Fromthenorthernmostextentofrecognizablegraniticbasementwestofthefaulttoitsnorthernmostextenteastofthefault,theminimumslipappearstobe550km,andfromthenorthernextentofFarallonridge 26kmorphologythemaximumslipis600km(Pig.2a)(Silverandothers,1971).Atotaloffset,of550to600kmalongtheSanAndreasfaultwasfirstsuggestedbyNentworth(1968)andhisevidencewasfurthersubstantiatedbyRoss(1972),basedonidentifyingoffsetsourceterranesforconglomerateswithintheGualalabasin.Howandwhenthisoffsetoccurredisonlypartlyresolved.Rightslipdisplacementof300kmpost22m.y.a.hasbeendocu-mentedonthecentralpart.oftheSanAndreasfaultbetweenSanFranciscoandtheTransverseRanges(Huffman,1972;Matthews,1976)andNilsenandClarke(1975)documentednooffset,onthatsegmentfrom45to22m.y.a.Xtisimportant.todistinguishoverwhatsegmentstheoffsetsapply,becausetheavailableinformationcanbeexplainedinseveralways.Oneisatwo-stage,singlefaultmodel(Suppe,1970)givingabout300kmoflateCretaceoustoearlyTertiaryoffsetontheSanAndreasfault,followedbyasecond,Mioceneandyoungeroffset,ofanother300kmonthefault..Asecondmodelisasinglestage-multifaulthistoryinwhichgreateroffsetscanoccuronthenorthernmostsegmentoftheSanAndreasthanfarthersouthduetosliponother,subparallelfaultswestoftheSanAndreas.TherecentstudiesoftheSanGregorio-Hosgrifaultzoneindicating100+15kmofright.-lateraloffset.supportthemulti-faultmodel,althoughtheoffsetmappedtodateisinsufficienttoproveasinglestagehistory.Graham(1976)mappedamaximumof35kmrightslipontheRinconadafaultbringingthemaximum documentedMiocene.andyoungeroffsetontheSanAndreasfault~sstemtoapproximately450km.ActivityontheSanGregoriofaultmay'playamajorroleinpartitioningstrainbuildupintheCentralCaliforniaregion.Studiesoflateraloffsetoffences,roads,railroadsandotherlinearmarkersaftertheSanFranciscoearthquakeof1906showedcommonevidenceforoffsetsof5m(16ft)ormorenorthofSanFrancisco,butonly21/2to3m(8to10ft)southofSanFrancisco(Lawson,1908).OneexplanationofthisdifferenceisalesserstrainbuildupontheSanAndreastothesouthbecauseofslipontheSanGregoriofault.TheHayward-CalaverasfaultzonesmayalsorelievestrainbuildupontheSanAndreassystem,butitisnotclearwhysliponthisfaultzoneshouldselectivelypartitionthestraindifferentlynorthandsouthofSanFrancisco(seeFig.3).Theremaining100(+)kmofbasementoffsetmaybeexplainedbyMioceneandyoungerundiscoveredslipalongotherfaultscuttingtheSalinianblock.Theirdiscoverywouldprove.theJohnson-Normarkhypothesis.Alternatively,approximately100kmoflateCretaceoustoearlyPaleoceneoffsetmayhaveoccurredontheSanAndreasfault,assuggestedbySilverandothers(1971)toexplainthedevelopmentoftheGualalabasininlatestCretaceoustime.Theyproposedarhombochasmopeningofanelongatebasintoexplainthebasaltflooredbasinfilledwith.verythick,coarseelasticsediments(Nentworth,1968).AnearlyTertiarySanAndreasfaultisalsofavoredbyNilsenandClarke(1975)toexplainearlyTertiarypaleogeographyandbasindevelopmentin 28~W~CentralCalifornia.DevelopmentoftheBasinsTheresultsofdrillinginthebasinswhichsuggestanearlysynchronousoriginofthecentralCaliforniabasinsinmiddletolatemiddleMiocenetime(roughly10to14m.y.a.),placetightconstraintsonhypothesesfortheoriginofthebasins.Forexample,anoriginrelatedtoasouthwardmigratingtripleVjunctionmustbeeliminated.herebecausethetimingofthismigra-tionwasoveraperiod8to10m.y;longfromabout29to20m.y.a.inthisregion.Theagedatagivenoindicationofanageprogressionintheoriginofthesebasinsandthetiming(10-14'm.y.'vs.29to20m.y.)isbetween6and'20m.'y.toolateforthismodel.ThispaperdoesnotdealwiththedevelopmentofthesouthernCaliforniaBorderlandbasins,butmostofthemapparentlydevelopedinaboutthemiddleMiocene(10to15m.y.a.)(Blakeandothers,1978).AccordingtoAtwater,(1970)themigratingtriplejunctionwasinthevicinityoftheBorderlandinmiddle.Miocenetimeaswell.ThusthesouthernCaliforniaBorderland,whilemuchmoreimpressiveinbasindevelopmentthancentralCalifornia,doesnotoffertheopportunitytodistinguishbetweenamigratingtriplejunctionvsamechanisminvolvingnearsynchronousdevelopmentofCaliforniaoffshorebasins.~ToinvestigatethepossibilityofachangeinplatemotionsbeingresponsibleforthenearsynchronousdevelopmentofthebasinswereconstructedthehistoryofPacific-.AmericamotioninmuchthesamewayasAtwaterandhiolnar(1973),andthencomputedaverageJ-28
~,~movementvectorsat36'N,121N,and33N,119Mfortheintervals0-4.5,4.5-10,10-21,21-29,and29-3Sm.y.TheresultsareshowninTable1.RotationsweredoneinareferenceframefixedtoNorthAmericaandinarestorativesensefortheglobalcircuitPacific-Antarctic-Indian-African-NorthAmericanplates.DatasourcesaregiveninTablel.ThethorolargestsourcesoferrorareinthecentralIndianOcean(Ind-Afr)andthecentralAtlanticOcean(Afr-NAm)becausetheserotationsrequire'thegreatestamountofdatainterpolationofseafloormagneticanomalies.Tectonichind-.castingofthissort.canbeimprovedupononlybymoredetailinthoseregions.InadditiontotheacceleratedrateofmovementinthelateCenozoicisthesignificantchangeofazimuth,especiallyafter21m.y.a.,'orsubsequenttothechangealongthiscontinentalmarginfromsubductiontotransformmotion.At36N,theazimuthis339'or21-10m.y.,328'ox4.5-10m.y.,and321~for0-4.5m.y.'I4Thesesuccessivelymorewesterly-directedmovementsofthePacificrelativetotheNorthAmericanplatemayhaveproducedextensionalstrainalongthecontinentalmargin,perhapsculminatinginthe-middleMiocene,about10-14m.y.a.Theextensional,strainwasmanifestedintheformationofthebasinsalongtheCentralCaliforniamargin,andperhapsthoseofthesouthernCaliforniaborderlandaswell.Sincethevectorsarecomputedfromfiniterotationpolestheyrepresentanaveragevalueforthetimeperiod,butnotnecessarilytheactualdirectionatanyspecifictime.IfitwerepossibletoJ-29 30\'qi~computerotationpolesforsmalltimeintervalswemightdiscoverthatthepoleofrotationbetweenthePacificandNorthAmericanplateshasbeenchangingcontinuallyduringthelast30m.y.Suchsmallbutcontinualchangesindirectionandrateofplatemove-mentsmayresultinthedevelopmentofa,complexstructuralgeometryintheareaoftheplateboundary,asobservedalongCentralCaliforniacontinentalmargin,andinfact,alongthe/entirewesternmarginoftheUnitedStates.CONCLUSIONSMarinegeologicalandgeophysicalobservationssupportthegeneralmodelofAtwater(1970)ofearlyTertiarysubduction\followedbyNeogenetranslationalshearalongtheCentralCaliforniacontinentalmargin.EarlyTertiaryrocksformirregularstructuralI,surfacesandshowrelative1yintensedeformation.Neogenestrataarewelllayered,mildlywarpedandcutbyhighanglefaults.LargeshelfbasinsformedalongthemargininlatemiddleMiocenetime,probablyfromacomponentofextensionalstrainduringplatetranslationalmovements.Platetectonicanalysisusingfiniterotationsaroundaglobalcircuit:Pac-Ant-Ind-Afr-NAM,showsachangeinaveragePac-NAMmovementduringaboutmiddleMiocenetoamoreextensionalsenseofshear.Thischangecouldberesponsibleforthesynchronousopeningofthebasins.Thisanalysisshowsa8changeinpoleofrelativemovementforeachinterval,andsuggeststhatinstantaneousmovementbetweenthePacificandNorthAmericanplatesmayhavechangedcontinuallyoverthepast30m.y.1 31Studyofthecontinentalmarginprovidesconstraintsonthc-offsethistoryoftheSanAndreasfaultsystem.Thenorthwardextentofgr'aniticbasementoftheSalinianblock,astracedbytheFarallonridge,limitsbasementoffsettobetween550and600km.Ofthisfigure,300kmoccurredontheSanAndreasfaultinNeogenetimebetweenSanFranciscoandtheTransverseridgesandupto150kmontheSanGregorio-HosgrifaultandtheRinconadafaultsouthofSanFrancisco.ThesevaluesaddtotheSanAndreasoffsetnorthofSanFrancisco.EarlyTertiarypaleogeographicandprovenancestudiesbyNilsenandClarke(1975),aswellasthedifferencebetweenmeasuredfaultslipandbasementoffsetarebestexplainedifsomeoffsetonfaultswithintheSalinianblockoccurredduringlatestCretaceoustoPaleocenetime.Thusatwo-stage,multifaultmodelforSalinianoffsetispreferred,.withabout100kmslipinlatestCretaceoustoPaleoceneandabout450kmpost-22m.y.,GraniticbouldersdredgedfromSantaLuciabankhavetwopossibleorigins.Xftheboulderswerelocallyderived,.graniticfaultsliversmustoccurwestoftheSalinianblockandthesimpleoffsetmodelpresentlyacceptedbymanyCaliforniageologistsmustberevised.Alternatively,thebouldersmayhavebeentransported100kmormorefromsourceareasintheSalinianblock.
~.'C~ITable1.Pacific-NorthAmericaFiniteMotions*36~N,121O'33'N,119WTimeIntervalm.y.RateAzimuth(1)(cm/yr)Azimuth(1)Hate(cm/yr)(2)4.5-0(3)10-4.5(4)21.2-10(4)29.2-21.2(4)38-29.232132833932'13205.64.53.23.81.73193263353193185.64.63.13.91.8*Summationofthecircuit:Pacific-Antarctic-Xndian-African-NorthAmericanplates.(1)Degreespositiveclockwisefrom.north.(2)AllrotationsfromMinsterandothers(1974).'II(3)Pac-Antfrom,Molnarandothers(1975).AllothersfromMinsterandothers(1974).(4)Pac-Ant:Molnarandothers(1975).Ant-Xnd:WeisselandoQ>ers(1972).Xnd-Afr:McKenzieand,Sclater(1971).Afr-NAm:,PitmanandTalwani(1972).
I~~32REFERENCESCITEDAtwater,T.M.,1970,ImplicationsofplatetectonicsfortheCenozoictectonicevolutionofwesternNorthAmerica:Geol.Soc.AmericaBull.,v.81,p.3513-3536.Atwater,T.M.andMolnar,P.,1973,RelativemotionofthePacificandNorthAmericanplatesdeducedfromseafloorspreadingintheAtlantic,IndianandSouthPacificoceans:Kovach,R.L.andNur,A.,eds.,StanfordUniversityPublica-tionsinGeol.Sciences,v.13,p.136-148.Bailey,E.H.,Irwin,W.P.,andJones,D.L.,1964,Franciscanandrelatedrocks,andtheirsignificanceinthegeologyofwesternCalifornia:Calif.Div.ofMinesandGeologyBull.183,177p.Beutner,E.C.andHansen,E.,1975,Structuralevidenceofplateinteractionsfromcontinentalrocks,CapeMendocinotoShelterCove,California(abs.):Geol.Soc.Amer.Abs.withPrograms,v.7,no.7,p.997.Blake,M.C.,Jr.,Campbell,R.H.,Dibblee,T.W.,Jr.,Howell,D.G.,Nilsen,T.H.,Normark,W.R.,Vedder,J.G.,andSilver,E.A.,1978,NeogenebasinformationandhydrocarbonaccumulationinrelationtotheplatetectonicevolutionoftheSanAndreasfaultsystem,California:Am.Assoc.PetroleumGeol.Bull.(inpxess).Buchanan-Banks,J.M.,Pampeyan,E.H.,Wagner,H.C.,andMcCulloch,D.S.,1978,Preliminarymapshowingrecencyoffaultingincoastalsouth-centralCalifornia:,U.S.Geol.SurveyMisc.FieldStudiesMapMF-910,3mapsat1:250,000.
Byerly,P.,1930,TheCaliforniaearthquakeofNovember4,1927:Seismol.Soc.AmericaBull.,v.20,p.S3-66.Crowell,J.C.,1962,Displacementalongth'eSanAndreasfault;California:Geol.Soc.AmericaSpec.Paper71,61p.Curray,J.R.andNason,R.D.,1967,TheSanAndreasfaultnorthofPointArena,California:Geol.Soc.AmericaBull.,v.78,p.413-418.Curray,J.R.,andSilver,E.A.,1971,StructureofthecontinentalmarginanddistributionofbasementrocktypesofcentralCalifornia(abs.):Geol.Soc.Amer.Abs.withPrograms,v.3,no.2,p.106-107.Gawthrop,W.H.,1977,SeismicityofcentralcoastalCalifornia(abs):Geol.Soc.AmericaAbs.withPrograms,v.9,no.4,p.422.Graham,S.A.,1976,.TertiarysedimentarytectonicsofthecentralSalinianblockofCalifornia:Ph.D.thesis,StanfordUniv.,510p.Graham,S.A.andDickinson,W.R.,1978,Evidencefor115kmofrightslipontheSanGregorio-Hosgrifaulttrend:Science,v.199,p.179-181.Greene,H.G.,1970,GeologyofsouthernMontereyBayanditsrelationshiptothegroundwaterbasinandsaltwaterintrusion:U.S.Geol.Surveyopenfilereport,50p.Greene,H.G.,Lee,W.H.K.',NcCulloch,'D.S.andBrabb,E.E.,II1973,Faultsandearthquakesintheh1onteroyBayregion,California:hiisc.FieldStudiesllapNP-518.J-34
~~Hamilton,N.,1969,MesozoicCaliforniaandtheunderflowofPacificmantle:Geol.Soc.AmericaBull.,v.80,p.2409-2430.FFall,C.A.,Jr.,1975,SanSimeon-EJosgrifaultsystem,coastalCalifornia:economicandenvironmentalimplications:Science,-v.190,p.1291-1294.Hanna,G.D.,1952,GeologyofthecontinentalslopeoffcentralCalifornia:Calif.Acad.Sci.Proc.,FourthSer.,v.27,p.325-358.Hopson,C.A.,Frano,C.J.,Pessagno,E.,andMattinson,J.M.,1973,LateJurassicophioliteatPointSal,SantaBarbaraCounty,California(abs):Geol.Soc.AmericaAbs.withPrograms,v.5,no.1,p.58.Hoskins,E.G.andGriffiths,J.R.,1971,FFydrocarbonpotentialofnorthernandcentralCaliforniaoffhore:Am.Assoc.PetroleumGeol.Mem.15,v.1,p.212-'228.Hsu,K.J.,1971,Francicanmelangesas.amodelforeugeo-synclinalsedimentation-andunderthrustingtectonics:Jour.Geophys.Res.,v.76,p.1162-1170.Huffman,0.F.,1972,LateraldisplacementofupperMiocenerocksandtheNeogenehistoryofoffsetalongtheSanAndreasfaultincentralCalifornia:Geol.Soc.AmericaBull.,v.83,p.2913-2946.Johnon,J.D.,andNormark,N.R.,1974,Neogenetectonicevolu-tionoftheSalinianblock,west-centralCalifornia:Geology,v.2,p.11-14.Kulm,L.D.,vonHuene,R.,andothers,1973,InitialReportsoftheDeepSeaDrillingProject,v.18,1077p.J-35
~~Lawson,A.C.,1908,TheCaliforniaearthquakeofApril18,1906:ReportoftheStateEarthquakeInvestigationCommission,v.1,451p.Martin,B.D.andEmery,K.O.(1967,GeologyofMontereyCanyon,California:Am.Assoc.PetroleumGeologistsBull.,v51(p22812304~Matthews,V.,XXX,1976,CorrelationofPinnaclesandNeenachvolcanicformationsandtheirbearingontheSanAndreasfaultproblem:Am.Assoc.PetroleumGeologistsBull.,v.60,p.2128-2141.'McCulloch,D.S.,Clarke,S.H.,Jr.,Field,M.E.,Scott,E.N.,andUtter,P.M.,1977,Asummaryreportontheregionalgeology,petroleumpotential,andenvironmentalgeologyofthesouthernproposedleasesale53,centralandnorthernCaliforniaoutercontinentalshelf:U.S.GeologicalSurveyOpenFileRept.77-593,56p.McKenzie,D.P.andMorgan,N.J.,1969,Theevolutionoftriplejunctions:Nature,v.224,p.125-133.McKenzie,D.P.andSclater,J.G.,1971,TheevolutionoftheXndianOceansincethelateCretaceous:Geophys.Jour.Roy.Astro.Soc.,v.25(p437528.Minster,J.B.,Jordan,T.H.,Molnar,P.,andHaines,E.,1974,Numericalmodelingofinstantaneousplatetectonics:Geophys.Jour.Roy.Astro.Soc.,v.36,p.541-576.J-36 Molnar,P.,Atwater,T.M.,Mammerickx,J.,andSmith,S.M.I'I1975,Magnoticanomalies,bathymetry,'andthetectonicevolu-tionoftheSouthPacificsincethelateCretaceous:Geophys.Jour.Roy.Astro.Soc.,v.40,p.383-420.Nason,R.D.,1968,GeologyofCapeMendocino,Dickinson,N.R.andGrantz,A.,eds.,StanfordUniversityPublicationsinGeol.Sciences,v.11,p.231-34.Nilson,T.H.andClarke,S.H.,Jr.,1975,SedimentationandtectonicsintheearlyTertiarycontinentalborderlandofcentralCalifornia:U.S.Geol.SurveyProf.Paper925,64p.Page,B.M.,1970,Sur-NacimientofaultzoneinCalifornia:Continentalmargintectonics:p.667-690.Geol.Soc.AmericaBull.,v.81IPitman,N.C.andTalwani,M.,1972,Sea-floorspreadingintheNorthAtlantic:Geol.Soc.AmericaBull.,v.83,p.619-646.Ross,D.C.,1972,PetrographicandchemicalreconnaissancestudyofsomegraniticandgneissicrocksneartheSanAndreas-faultfromBodegaHeadtoCajonPass,California:U.S.Geol.SurveyProf.Paper698,92p.Seeber,L.,Barazangi,M.,andNowroozi,A.A.,1970,Micro-'arthquakeseismicityandtectonicsofcoastalnorthernCalifornia:Seismol.Soc.AmericaBull.,v.60,p.1669-1699.Silver,E.A.,1974,Structuralinterpretationfromfree-air/gravityontheCaliforniacontinentalmargin,35'o40'N(abs):Geol.Soc.AmericaAbs.withPrograms,v.6,no.3,p.253.J-37 Silver,E.A.,Curray,J.R.,andCooper,A.K.,1971,TectonicdevelopmentofthecontinentalmarginoffcentralCalifornia:.inLipps,J.andMoores,E.M.,eds.,GeologicguidetothenorthernCoastRanges-PointReyesregion,California:Guide-book,Geol.Soc.SacramentoAnn.FieldTrip,p.1-10.ISuppe,J.,1970,OffsetofLateMesozoicbasementterranesbytheISanAndreasfaultsystern:Geol.Soc.AmericaBull.,v.81,p.3253-3258.Uchupi,E.andEmery,K.O.,1963,ThecontinentalslopebetweenSanFrancisco,Californi'a,andCedrosXs.,Mexico:Deep-SeaRes.,v.10,p.397-447.Nagner,H.C.,1974,MarinegeologybetweenCapeSanMartinandPt.Sal,south-centralCaliforniaoffshore:U.S.Geol.SurveyOpenFileReport74-252,17p.Neissel,J.K.andHayes,D.E.,1972,MagneticanomaliesintheSoutheastXndianOcean:AntarcticOceanologyXX:TheAustralian-NewZealandsector,Hayes,D.E.,ed.,AmericanGeophysicalUnion,Nashington,D.C.,p.165-196.Nentworth,C.M.,1968,UpperCretaceousandlowerTertiarystratanearGualala,California,andinferredlargerightslipontheSanAndreasfault:inDickinson,N.R.andGrantz,A.,eds.,Proc.Conf.Geol.ProblemsoftheSanAndreasfaultsystem:StanfordUniv.PublicationsinGeol.Sciences,v.11,p.130-143.'oodring,N.P.andBramletteiMNi1950,GeologyandpaleontologyoftheSantaMariadistrict,California:U.S.Geol.SurveyProf.Paper222,185p.J-38 FIGURECAPTIONSFigurel.Trackofgeophysicalcruisesandgeologicsampleloca-tionsonthecentralCaliforniacontinentalmargin.Heavylinesareseismicprofilesillustratedinthispaper.Identificationofseismicprofilesbycruise:W=ThomasWahingtonK=KelezS=Bartlett1972,leg1.L=Bartlett1972,leg2LDM=DavisprofileIdentificationofsamplesbycruise:D=KelezDredgeF=KelezDartCoresADC=Melville(Antipode)DartCoreAD=Melville(Antipode)Dredge7DS=ThomasWashingtonDartCore(7Tow)B=BartlettDredgeFigure2.MapofstructuralfeaturesonthecentralCaliforniacontinentalmargin.Locationofridges,basinsandmajorfaults.CM:CapeMendocino;PA:PointArena;PR:PointReyes;SF:SanFrancisco;M:Monterey;SS:SanSimeon;PS:PointSal;PC:Point.Conception.Figure3.Mapoffaultsandfoldsonthecontinentalmargin.Figure4.LinedrawinginterpretationofBartlettseismicreflectionprofilesL16toL20acrosstheSantaMariabasin.J-39 Figure5.LinedrawinginterpretationofBartlettseismicreflec-tionprofilesL2toL14acrosstheSurandSantaMariabasin.Figure6.Free-airgravitymapofthecontinentalmargin,from35'o40'North.ContouredfromNationalOceanSuryeyunpublisheddata.Contourinterval10mgal.Figure7.Residualmagneticmapofthecontinentalmarginandoceaniccrusttothewest.MapiscombinedNationalOceanSurveydataandBartlettdata.Figure8.CrustalmodelsatisfyingobservedgravityforprofileL18.2.65means2.65gm/cc.Noscaleexaggeration.Eastisontheright.Figure9.ReflectionprofiletakenbyD.G.MooreacrosstheISantaMariabasinshowinglocalfoldingofstrataagainsta"buttress"ofacousticbasement.LabeledLDMonFigure1.Figure10.LinedrawinginterpretationofThomasWashingtonprofilesW6,8,ll,12,13,16,18,19,and23.FromExpedition7-Tow,leg9B.Figure11.LinedrawinginterpretationofreflectionprofilesKl,3,44,66,68,and93,fromtheR/VKelez.Figure12.Linedrawinginterpretationof'reflectionprofilesSl-S4,fromleg1ofR/VBartlettin1972.ProfilescrossouterSantaCruzbasinandSantaCruzhigh.Figure13.LinedrawinginterpretationofprofileNX,takenalong'heaxisofOconostotaRidge.J-40
~~~Figure14.Geometryofhypotheticalstableandunstablefault-fault-trenchtriplejunctions,predictednewconditionofstabilityandgeneralizedobservedgeometry.a)Stablefault-fault-trenchtriplejunction.b)GeneralizedunstableformofMendocinotriplejunction.c)Predictednewpositionofstability=Ridge-Ridge-Ridge.triplejunction(thissolutionisfromClementChas'e,Univ.ofMinnesota,oral,commun.,1976).d)GeneralobservedgeometryofMendocinotriplejunction,illustratingbendingofSanAndreasfaultatitsnorthernend,ratherthantriplejunctionevolution,tomaintaingrossgeometricstability.
KsrarSS~KILCKCTERSIOOPIti~~a0ag/Vl/x0+oaa0~4'I~Vo~+~0yeaeeVCEOKKTSICALTRACK0OREOCCORDARTCCRCCONTOURINTERVALSOOIICTCRS~h,a,,/pOz'JaSSA0,aaafeaSoI0K<LOUETERSOc.'1LIaa.>SSIWSSsras.SrSSiltV l23~40'22~39~l2'8'7l20'6'5~l25~GraniticridgeFranciscanridgeBasinFault.ptl,tt'0CALASERA9B'AV~,'qu;Anp~t-QAiC$AV"'-"~"ANGRINGO:J,SVR.,;,;-.~hp9GRIFAV7R:0FAV'.FAPr.Arrno80$cn~z~~zr/A...-~:;;:';.*.~ZZ~BASE4~~OF~~~~~CONTINENTAL'.."-"""LOPE~+~~~~~~34~I200l2PtppKitomoters40+39~38~l25~37~l24>>36~35l23'4~l22~
It5~50ST+SV55>>-C-XXXTAULT,NACNUNCSOHOONNTHAOWMSTOCfAULTTONICAHTICLIAC01SASS@TNT1ICCCSTNCLINC01~ATINATISVOLCAN>C1IOCCLA"<<ASNAVSAAOTAULT5AllAHOCfAULTlCCyoAII&oem+fAifatOASNIpie~IOOCO+OSTOTASLOrCCON'5INLNSASCXILOIICT515AINCO<AOATAU'TfAULT~0fTAULT~SAAIANOACAS~P~ALCOO~~f4'~,c.'--Nlll15(CAVCSA>>NUOA~,~SAIITATOUTIgg+~<11S0IOO554P55It5'5ITS55RiItt t40120804020Km0~0SantoLuciaBankSontoferroBasrnC./.KPSecL16/rr6aCZlalk.~~~/r20Km00<<cL1820Krn00s<<L20F~-wr+r~r+/i/~ci$:"rr~rr050020Krn00/q'r"=--.=;-'==--.=-~~.Q/i~SecFcurt20Km0Qgr-SecL24r/MVQ~~s<<L2620Km207<<cL28SantaBankFaultV,Kp10K
~~4020,Km0SecKm200SecL40~r/Cr~p.r/rSecL620Km00scLgr20Km0pgr2riSecL.1020Km00c'20Km00scocc.scMo.pc~8KjP.220Km00ISurBasinigf/r,rrcS'rSrrrrV.E.~10K~oJ-46 I25'cc)pc1r4c123'22c4acO0O30c38cBodegaHeadI38'7~125c00SanFrancisrPt.Reyes38'-'"C'c>Pt.AnoNuevo121'7c70.p((..oo~~""..MontereyPointSurrc~~c~'-+yy38c050KMInterval10mpalFREE-AIRGRAVITY4@~~EcrcrcBay35'24c123c122c35'21'-47 4pe12S123~t122'200400I~~Qm,MQ'II0(')FTARCNAVMAGNETICANOMALYIMEANSIOOnT(gommos)CONTOURINTERVAL:100nTINACTIVETRARSFOIIMFAULTBASKOFCONTINEtlTALSLOPE.UNCONTOUREDtlAGNKTICHIGHMAJORFAULTSg,g~ODCCA3t)036'.Cg~+5ANFRANCISCO0.5AN)ACRV?01MCNTCRCT~~ATNONTCIICT/I0IIIICo0+000N)LOMCTCN537036'5'C3/Q/CVCNON)(.)0J~T,5ACI350I'.ANCVCLL34'2500.I1240-.Yn1230J-,48 FREE-AIRGRAYITY0-04Q~m~mgal-IOO-CALC.SantaLuciaBank0KMIO2.85I.032.250I02.652.2I0203.273.03.23 500)0006VertjoaiExaggeration:XIO
,~~~~~IE0s~W6~SW0sgf,~l.secWBCger.'~eA022.~-'.J.<'nl00~*';~OJj~.V/11s~JJJJrKnl00~==;.-0Km00rr/g~r.r+Zi"CJ'secW160sW180secW19.J).jo22Km20SodegeOoselForooonJVF.ecsxsecW23 4X0+3ArV.'5uovo5101510ivOtvOH~,01OC~5uo41o!555tuivut'10l5I4e01OCor7rCOr~OF~rjv'9M~s55vov>ooo5101vutAlp,!,-:.~j~"=..':-~.~51>)l1<c01OCOCOF0005OrO5v001O;075lO'IvotuCHF'SC,rIJ0000d~r'.rKr5tv~ukDQo5opoQ>ryr$rOrSPrrv01OZCC~Or000001CO05 e80=4020Km0.0PioneerSeamount4+4fe~~4OutcrSontaCruz~~~~~/rForollonRidge20Km0~fMY;0Sec5$Sec$QGuideSeamountl20Km00SantaCruzHigh,ir'0'Km~~d~\~PlrPe.'~r--.-~AV.Ep6X IO80706050KILOMETERS4020IO020003003CL-OO1JJ40
~0StabilityConsiderationsofaFFTTripleJunction0)StableFFT8}Unst'ableFFTGordaPacificAmericaPllGWPGVelocityTriangleGordaPacific,America)GAIGlIAlIC)NewStabilityConditionafter(D)RRRAmericaPGPD}MendocinoFFTTripleJunctionGordaAmericayl'PacificPAAPacificPAmeansPacific-AntericaPlateBoundaryplottedonvelocity'riangleJ-55 N
~~~'~I~~~~~~4~~~~~~Appchica'".ionofItnears'Latts'Ltcalmocielsofear&quakemagnitucxeversusfault.Iengt>ttnesct!TlaLtngrnaxImu~~e;,pec'cableearthquaI:es0~ir~~rr~Nrr'\r~~~r~,'lC~~;1rRobert>xMarl'.S.GeologicalSurveMenl,Park,California940"';ABSTRACTCorrelationorlinearrcgrcssionestimatesofearthquai;cmagnitudefromdataonliistoricalmagnitudeandlengthofsur-'aceruptureshouldbcbaseduponthecorrectregression.I'orexample,thcregressionofmagnitudeonthclogarithmofthclengthofsurfacenipturcLcanbeusedtoestimatemagnitude,butthcrecessionoflogLonmagnitudecannot.Rc~ccssiottcstimatcsarcmostproliablevalues,andestimatesoftnaximumvaluesrequireconsiderationofonewidedconfidencelimits.lOOOC'OD~~~~~rr~'INTRODUCHIONInestimatingmaximumexpectablecarthquakcs,itiscommonpracticetoassumeapaximumlengthofsurfacerupture(typicallyonc-halfthefaultlength)anduse"linesofbestfit"tocstimatcmaximuinmagnitudefrontgraphscomparinghistoricalcarth-quakcmagnitudesandlcrgtlisofassociatedsurfaceruptiircs.Thisnotediscussesthcintcrprctatinnanduseoflinearregressionorcorrelationmodelsforniakingstatisticalinferencesfromdataon'istoricalevents.Fnrcxamplc,DnniDaandDuchanan(1970)re-portedlengthofsurfaceruptureLandRichtermagnitudehfforthoseearthquakesforsvhiehthesedatav:ercavailableandprc-scntcd"bestfit"equationsofthcformlngLa+bhf,thatis,thclinearregressinnsoflogLnnmagnitude(Fig.1.lincAA').Otheiauthors(fnrexanipie,Tocher,195S;lido,1965)liavccalcu-latedrcgrcssinnsofma<!iiiludcnnlogL(Fig.1,linesDD'ndCC').Iwillarguethatalltheserel!ressinnlineshavebccnusedilt-corrcctlytocstiinateniaxiniumearthquakemagnitudesfrommaximumruplurclenglhsa.'nngfoul!s.Thatis,th"v:rorgregres-sionlinc(lngLoninagnitudc)hasbeenusedtocstimatcniagnitudcfromniaximumrupture)englli,orregressionestimateshavebeeninterpretetlasmaximuinralherthenninctlikelymal!niluilcs(fnrcxaniplc,Greeneanilnlhers,1973;5'entwnrthandnlhers,1973;KYessonandnthers,1974.1975).ceCJC'>Ir.io>JiOe8e>pctaAs~Ds0ecr4t:ARTHQV/AEuse>r'>TUBE1'igurcl.I.engihnfnt>se>vedsn>beeinpiuieinictstiin>Inesiih.quaken>a::nilude.l.ine*Aissiegiessionlinenflngl.on>n.>dniin>.c.Linestill,CC',andtill'ic>cpassi>>ntinesuriuagniiudeunt>>grJ..l.inAA'ndI)t)'icbasedunihes>>ncdata.K-1GCOLOGY,v.6,p.dG4-4GG,AUGUST,t'ai
.rItWACORRELATIONMODELManymodelscanbeusedtodrawstatisticalinferencesfromthcdataonmagnitudeandlcng(hofrupture.AtransformationtologI.isusedbccauscittendstonornulizcthcdataandtocn-hanccthclinearrelationship.Forthcpurposeofthisdiscussion,acorrchtionmodelispostulatedinwhichitisassumedthatnmagnitudeversuslogLdatapointsarcranclocnlydrawnfromthepopulationofcarthquakcs1vithassociatedsurfaceruptureandthatsuchapopulationhasabivariatcnorcnaldistribution(Fig.2).Asindicatedblow.theseassumptionsarcmorcrcstrictivcthannecessary.AsshowninFigurc2,thcrcgrcssionlincol'onX,orY~a+1}X,passesthroughthcmostprobablevalueofYforeachXandisthcappropriatelinctocstimatcYgivenX.Theotherregressionlinc,thcrcgrcssionofXonY,passesthroughthcmostprobablevalueofXforeachYandwillnotprovideanunbiasedestimateofYgivenX.Thus.thclineofBonillaandBuchanan(1970}inFigurc1isnotthecorrectregressionlineforestimatingearthquakemagnitudefromfaultlength.Itather,thcappropriateregressionofmagnitudeonlogL,calculatedusingtheirstrike-slipfaultdata,isliucDD'Fig.1).Itissimilartothcequivalentregressionlinesofthcotherauthors.ESTIV)ATIONOFMAXIMUMEARTHQUAYMMAGNITUDESThcregressionlinesofrnagnitudconlogLcanbcusedtoestimatethcmostlikelyrnagnitudcforagivenmaximumrupture.Itmustbcstressedthatsuchanestimateisriotamaximummag-nitude,butratherthcmagnitudethatcouldbcexpectedtobeexceededin50%ofthcearthquakesassociatedwiththatrupturelength.x=ccrcgg0PxItispossibletousethcstatisticalmodeltoestimatethcmag-nitude,asafunctionoflength,thatcouldbccxpcctedtobecx-cccdcdinagivenproportion(1-cc}ofsurface-ruptureoccurrences.usingaonc-sidedconfidencelimit(IVonnacottandIVonnacott,1972,p.280):fcfrr,(L)=ilf(L)+ltcx,s(logL-la~7.)'I-+I+5(logLl-logZ)~l~twhereM(L}isthercgrcssionvalue,r,.o,isthccriticalvalueofthcldistributioncvith(n-2}degreesoffrccdom,sisthcstandarderrorofthcrcgrcssion,LlisthcruptureIcnl<hofthcithcarth-quakcoccurrenceinthesampleofnearthquakes,andlogListhcmeanoflogL.Thatis,thccurvei'Vx(L)isthclocusofpointssuchthatforaparticularL.I-ccisthcprobabilitythatthemagni-tudewillcxccedhQ.NotethattheregressionlincM(L)isequiva-lenttoM,.,(L}.Asancxamplc,BonnillaandBuchanan(1970)reporteddataonstrike.slipfaults(n~20)andcalculatedthercgrcssioalinc(Linmctrcs}'ogL~1.915+0.389M,r~0.70,s~Q.S2.TheregressionofMonlogL}acidsM~1.235+1.213logL.r~0.70,s~0.93.TheselinesarcplottedinFigurc3,alongwiththodatapoints.Alsoplottedarcthecurveshf>.>>andM,>>lorthcregressionofMonlogL..Amagnitudevaluefromthercgrcssionlinc'f(L)canbcrcfcrredtoasthemostlikelym..gnitudeforagivenrupturelength,andavaluefromhfJL)asamaximumcxpcctablccarth-quakcmagnitudeatcxcccd*nceprobability'-cc.ThclineEE'nFigurc3cocmectsthepointsthatformtheright.sidecnvelopcofthedata.ThisfieldliescntirclytotheleftofMo>>,andonthcbasisofthcmodel.therearepotentialcvcntslargerthanEE'hathaveprobabilitiesinexcessof5%.Thcprcccdingnumericalresultsaresomewhatmodeldcpcnd-cnt,inthattheydcpcndonthepopulationdistributionandsscnpleselection,butthcgenera)hnplicationshavewideapplication.Estimatesofmostlikelyearthquakemagnitudesforagivenvalueofan"indcpcndentvariable"(suchasrupturelengthorfaultdisplacement)mustbebasedonthccorrectrcgrcssion,andesti-matesof"maximummagnitude"rcquircconsiderationofthedistributionaboutthcregressionlincandthcapplicationofonc-sidcdconfidencelimits.TheseresultscanalsobcderivedfromalessrestrictivelineartcgrcssionmodelinwhichlogListreatedasanindependentvari-ableandMisassumedtobcnormallydistributedaboutthcrcgrcssionli>>e(AfonlogL)withvarianceindcpcndcntofL(Hays,1973,chap.IS).ll'hedatawarrant,thcscmodelscouldbeex-pandedtoincludeadditional"independentvariables"suchastectonicsettinganclhypoc.cntraldepth.Astatisticalapproachisalsonccdcdtocsticnatcthcmaximuntsurlaccrupture(atsomecxcccdanceprobability)foragiventotalfaultlength.Flcclcc2,'Yhctcvoccyccs)lollthwsic)0t)lvaliatcllocmatpop))tattoo,ccontoc)czindicatectealpc))tat)ilitydensity,~t)))tificdfrocu4'vc)c)acuttand4ocmacocttt97)).xcecdancepcobabilityistheprobabilitythatsomcthi))t.,inthiscasemat.nitudc,vcttt)ccxcccdcd.GP.OLOGYK-2 QI)30h~hsRrgolsv4~4Don)()a,hl.G.,andBuchanan,J.I'l.,1970.Interimrcportontvorldsvidchistoricsurfacefaulting:U.S.Geol.SurveyOpenFilel(ep(.,32p.Grccnc,SV.H.,I.ec,W.l).IL,hlcColloclhILS.,andBrabb,)LI1973.I'aultsandearthquakesinthchtontcreyDayregion,California:U.S.Geol.SurveytexttnaccompanymapMF518,14p.)lays,W.L.,)973,Statis(icsforthcsocialscicncesrNcsvYork,)lolt.Rinehart,andWinctnn,954p.lida,Numizi,196S,I'.arthquakcmagni(ude,earthquakefaultandsourcedirncnsions:NagnyaUniv.Jour.ForthSci.,v.)3,p.II5~)32.Tochcr,Don,1958,Lsar(l>qua),"eenergyandgroundbreakage(Seismol.Soc.AmericaBull.,v.48.p.147-)53.Wcsson,R.L.,I'agc,R.A.,Boore,D.hl.,andYerkcs,R.I'.,1974,Isx.pcctablecarthquakcsinthcVanNo(roanReservoirsarea:U.S.Geol.SurveyCirc.69)-B,9p.Wcsson,R.L.,)le)Icy,E.J.,Lajoie,K.R.,andWcnttvorth,C.M.,1975,Faultsandfutureearthquakes,fnIrorcherdt.R.D.,cd.,StudiesforseismiczonationofthcSanFranciscoflayregion:U.S.Geol.SurveyProf.Paper9CI-A,p.AS-A30.Wenhvorth,C.h'l.,Beni))a,M.G.,andBuchnan,J.hl.,1973,SeismicenvironmentofthcBurroFlatssite,VenturaCounty.California(U.SGeol.SurvryOpen.FileRcpt..35p.Wonnacott,Thorn..sH.,andWonnacott,RonaldJ.,19'12,introductorystatisticsforbusinessandeconomics:NcsvYork,Wiley,622p.J(CIÃQAYLEDGMEHTSRcvicwcdbyD.R.Dasvdy,D.G.Ilcrd,R.A.Page.andD.hl.Perl:ins.hlANUSCRIPTRECEIVEDAPRIL27,1977MANUSCRIPTACCEPTEDMAY3,1977IA3q85C66078KARTHQVAN\s(AH(TVDEFigurc3.Lengthofobscrvcdsurfacerupturcvcrsusearthquakemagnitudeforthcstrikeslipfaultda(aofllunithandLtuchanan(1970).LincAA'sthcregressionlincol'ng1.onmacnitudeamlcouldbeusedloestimatethcntostlikelytuplurclengthassociatedsvithagivenmagni.tudcearthquake.I.incIIps'stherctuessiunlineofmagnitudeonlogIandc'ouidbcusedtocstunatethcmustlikelyearthquaketnagnitudeassociatedwitharivenlrngthofsurface(upture.Onthcbasisoi'hccorrelationrnnAI,halfthccarthqua'kcsassociatedwithagivenlengthufsur(accrup(urerouhlbceapcctcii(ulsclargerthanIIIJ.Themarnitudcs'givenbylincDl)'ou)Jbceapec(cdtnexceed95%,ofthea(agni(udesfurearthquakesassucia(edwithagivenI;ngthofsurface(up(urc.ThclincEE'stheri).ht.sh(cenvelopeofobserveddata.K-3~WHlleINvsaAUGUSi
ATTACHMENTLUNITEDSTATESDEPARTMENTOFTHEINTERIORGEOLOGICALSURVEYREGRESSIONANALYSISOFEARTHQUAKEMAGNITUDEANDSURFACEFAULTLENGTHUSINGTHE1970DATAOFBONILLAANDBUCHANANByR.K.MarkandM.G.BonillaPreparedincooperationwithU,S.NuclearRegulatoryCommission.OPENFILEREPORT77-614ThisreportispreliminaryandhasnotbeeneditedorreviewedforconformitywithGeologicalSurveystandardsandnomenclature.MenloPark,Ca1ifornia1977 REGRESSIOHANALYSISOFEARTH(UAKEMAGNITUDEAHDSURFACEFAULTLENGTH,USINGTHE1970DATAOFBONILLAANDBUCHANANByR.K.Harkandt1.G.BonillaIntroduction.ThereportofBonillaandBuchanan(1970)includesre-gressionsoffaultlengthonearthquakemagnitudethatcanbeusedtoestimatemostprobablelengthofsurfacerupturegivenearthquakemagni-tude.Thoseregressions,however,havesometimesbeenincorrectlyusedtoestimatemagnitudefromfaultlength,aspointedoutbyHark(1977).UsingthedataofBonillaand'Buchanan,thisreportgivesregressionsofearthquakemagnitudeonlengthofsurfacerupturethatcanbecorrectlyusedtoestimatemostprobablemagnitudeifthelengthofsurfaceruptureisgiven.Italsogivestheregressionsoflengthofruptureonmagnitudethatcanbeusedtoestimatemostprobablelengthofrupturegivenearth-quakemagnitude.Intable1andfigures1-5thenumberingandletteringsystemusedtodesignatefaultgeographyandfaulttypesisthesameasinBonillaandBuchanan(1970).Numbers1-49includesurfacerupturesthatoccurredinNorthAmericaandnumbers50-140includerupturesoutsideofNorthAmerica.Thefaulttypesareindicatedbylettersasfollows:A,normal-slipfaults;8,reverse-slipfaults;C,normaloblique-slipfaults;0,reverseoblique-slipfaults;andE,strike-slipfaults.Useofthereressionlines.TheregressionofloglengthonmagnitudeL-2
~~(LogL=a+bM)canbeus<<dtoestimatethemostprobablerupturelengthgivenmagnitude,andtheregressionofmagnitudeonloglength(M=a+bLogL)canbeusedtoestimatethemostprobablemagnitudegivenrupturelength.Theestimationof'maximummagnitudes'oragivenrupturelengthrequirestheuseofone-sidedconfidencelimits(Hark,1977).ReferencescitedBonilla,H.G.,andBuchanan,J.M.,1970,Interimreportonworldwidehistoricsurfacefaulting:U.S.Geol.Surveyopen-filerept.,32p~Mark,R.K.,1977,ApplicationoflinearstatisticalmodelsofearthquakemagnitudeversusfaultlengthinestimatingmaximumexpectableY.Sqp+~++6b~AUQ0sl.earthquakes:Geology,+a-p~.'AL-3 Table1Regressionanalysisofmagnitude-surfac'erupturelengthdatafromBonillaandBuchanan(1970).fset1-49nr~200.3?21-140530.257140.17570.00370.45950.00650-140330.21710.64.8.57.Log(L)=a+b~Hab-0.910.35-1.490.402.550.014.240.02-0.690.28notsignificant-2.810.61notsignificant17.62-0.960.34N=a+b*Log(L)b1.080.540.760.630.900.640.800.680.386.080.750.42sa0.51'.230.556.560.536.030.456.19-EA+C210.2797.37-1.460.40200.484.16.87-1.080.390.524.960.456.131.240.930.700.59B+DC+D+E120.0330.34320.36717.42-1.240.40notsignificant0.555.620.93084120.'2302.99-2.790.590.576.620.390.47B+E270.29910.65-0.710.320.565.710.940.97A+C+E410.38023.94-1.200.390.495.560.990:79B~D+E320.25110.07-0.810.320.605.980.780.93Notes"n"isthenumberofcases."t"isthefractionofthevarianceexplainedbytheregression.Itrangesfrom0(nolinearrelationship)to1(perfectlinearrelationship)."f"isameasureofstatisticalsignificanceoftheregressionandisequaltor~/.((1-8)(n-2))."L"isinkilometers."s"isthestandarderroroftheestimate.s~isequaltotheresidualsumofsquareerrorsabouttheregressionlinedividedbythedegreesoffreedom(i.e.,n-.2).L-4 SICKO,800'0060050Q40050020Q0KELJIOO090hC8070I-6oDu.5040soDI-20SORLDV/!DEDATA0Ob.IO0987Rld65O0X0/tp0hO+OEOI/O05tEARTH'QUAKFMAGNITUOEL-59Fip.l IOOO800eOO700600500400300200MLIJI-IOO09080hC706050NORTHAMERICANDATA40<<KQJ30ILI-LL.20KLalOIoLL.9O8I-7Z6LLJV~o~OaOO4Q6EARTKQUAKEMAGNITUDEL-67'9Fig.2 9oo~'(~800700600500400500200V)CLLalleloo0908070I-Go50NORMAL-SLli~FAULTDATA40ZsoKI-tL20u-,lo0987R650'0XCnO0+Cb56EARTHQUAKEMAGNITUDEL-7/)
IOOOeno800700600500400500200VlfLldI-ion0908070I~60U50R40lLsoDI-020ORBALOBLIQUE-SLtPFAULTDATAOKDlo09I-8LU50OhO+DCOII56EARTHQUAKEMAGNITUDEL-8
.aoo000700600500400300200COLLII-ObCLL.IOO9080706050STPiIViE-SLIPFAULTDATAcfLLJI-tLDLLjCDtOLLOxI-E9zLLJ403020lo87650o'./jChO0)56EARTHQUAKEMAGNITUDE I~
~g'~INAMEJamesN.BruneATTACHMENTMBIRTHDATE(MO.,DAY,YR.)November23,1934BIOGRAPHICALSKETCH(PROVIDEFOLLOWINGINFORh)ATIONFORALLPROFESSION~RSONNELENGAG~TIIEPROJECT,BEGINNINGWITHTHEPRINCIPAL~TIGATOR.)PLACEOFB(RTH(CITY,STATE,COUNTRY)Modesto,CaliforniaU.S.A.PRESENTNATIONALITY(ALIENSINDICATEKINOOFVISAANDEXPIRATIONDATE)U.S.CitizenEDUCATION(BEGINWITHBACCALAUREATETRAININGANDINCLUDEPOSTDOCTORAL)DEGREEB.Sc.Ph.D.YEARCONFERRED19561961INSTITUTIONANDLOCATIONUniversityofNevada,Reno,NevadaColumbiaUniversity,NewYorkCityHONORSANDAWARDSSeeAttachedMAJORRESEARCHINTERESTEarthquakeSourceMechanismTectonicsEarthStructureRESEARCHAND/ORPROFESSIONALEXPERIENCE(STARTINGWITHPRESENTPOSITION,LISTPROFESSIONALBACKGROUNDANDEh'IPLOYMENT)ProfessoroIGeophysics-UniversityofCalifornia,San'Diego,1969-AssociateDirector,InstituteofGeophysicsandPlanetaryPhysics,UniversityofCalifornia,SanDiego,1973-1976..Chairman,GeologicalResearchDivision,ScrippsInstitutionofOceanography,UniversityofCalifornia,SanDiego,1974-1976.AssociateProfessorofGeophysics-CaliforniaInstituteofTechnology,1965-1969.AdjunctAssociateProfessorofGeology-ColumbiaUniversity,1964.Geophysicist,U.S.CoastandGeodeticSurvey,1964.ResearchScientist,ColumbiaUniversity,1958-1963.'xplorationResearch,ChevronOilCompany,1957.ExplorationGeophysics,ChevronOilCompany,1956.
UCSD-0071JamesN.Brune.HONORSHigginsFellowship,ColumbiaUniversity,1956UniversityFellowshipinGeophysics,ColumbiaUniversity,1957-58i)axFleischr~~anScholarship,UniversityofNevada,1954-55Jones-HooverScholarship,UniversityofNevada,oneyearJ.B.HacIlwaneAwardofAmericanGeophysicalUnion,1962FellowoftheAmericanGeophysicalUnion,1967GroveKarlGilbertAwardinSeismicGeology,1967Seismol'ogicalSocietyofAmerica:BoardofDirectors,1967-present,Yice-President,1969,President,1971Meri>berofNewYorkAcaderi>yofSciences,1970ArthurL.DayAward,1972G..K.GilbertAward,CarnegieInstitutionofWashington,1967Llstlngsinvhosvhointhevest,kne2icanZenofscienceM-2 BIBLIOGRAPHYJamesN.Brunel.2~(WithJ.Oliver)TheSeismicNoiseoftheEarth'sSurface,Bull.Seism.Soc.Amez.,49:4,349-353(1959).(WithJ.E.NafeandJ.E.Oliver)ASimplifiedMethodfortheAnalysisandSynthesisofDispersedHaveTrains,Jour.Geophys.Res.,65:1,287-304(1960).3~(WithJ.E.Nafe)ObservationsofPhaseVelocityforRayleighWavesinthePeriodRange100to400Seconds,Bull.Seism.Soc.Amer.,50:3,427-439(1960).4~RadiationPatternofRayleighWavesfromtheSoutheastAlaskaEarthquakeof10July1958,Domin.Observ.,24,20,ASymposiumonEarthquakeMechanism,1-11(1961).5.6.7.8.(WithM.EwingandJ.Kuo)GroupandPhaseVelocitiesforRayleighWavesofPeriodGreaterthan380Seconds,Science,133:757(1961).(WithJ.E.NafeandL.E.Alsop)ThePolarPhaseShiftofSurfaceWavesonaSphere,BuZZ.Seism.Soc.Amer.,51:247-257(1961).(WithH.BenioffandM.Ewing)Long-periodSurfaceWavesfromtheChileanEarthquakeofMay22,1960,RecordedonLinearStrainSeismographs,Jouz..Geophys.Res.,66:9,2895-2910(1961).AttenuationofDispersedWaveTrains,BuZZ.Seism.Soc.Amer.,52:1,109-112(1962).9.10.11.12.13.14.(WithJ.T.KuoandM.Major)RayleighWaveDispersioninthePacificOceanforthePeriodRange20to140Seconds,Bull.Seism.Soc.Amez'.,52:27333-357(1962).CorrectionofInitialPhaseMeasurementsfor'theSoutheastAlaskaEarthquakeofJuly10,1958,andforCertainNuclearExplosions,Jouz.Geophys.Res.,67:9,3643-3644(1962).(WithM.EwingandJ.Kuo)SurfaceWaveStudiesofthePacificCrustandMantle,Geog.Monograph,6,CrustofthePacificBasin,(1962).(WithJ.Dorman)SeismicWavesandEarthStructureintheCanadianShield,Bull.Seism.Soc.Amez.,53:1,167-209(1963).(WithA.EspinosaandJ.Oliver)RelativeExcitationofSurfaceHavesbyEarthquakesandUndergroundExplosionsintheCalifornia-NevadaRegion,Jour.Geophys.Bes.,68:ll,3501-3513(1963).UseofSurfaceHaveRejectionFilterstoRecordMantleHavesofLowOrder,"~-EarthquakeiVotes,34:73(September-December1963).(Abstract)M-3 N.Brune-Biblioghy~~(WithP.E/.Pomeroy)SurfaceWaveRadiationPatter'nsforUndergroundNuclearExplosionsandSmallMagnitudeEarthquakes,Jour.Geophys.Res.,68:17,5005-5028(1963).TravelTimes,BodyWaves,and'NormalModesoftheEarth,Bull.Seism.Soc.Amer.,54:6,2099-2128(1964).(WithR.Chander)RadiationPatternofMantleRayleighWavesandtheSourceMechanismoftheHinduKushEarthquakeofJuly6,1962,Bull.Seism.Soc.Amer.,55:5,805-819(1965).(WithL.E.Alsop)ObservationsofFreeOscillationsExcitedbyaDeepEarthquake,Jour.Geophys.Res.,70:24,6165-6174(1965).TheSaPhasefromtheHinduKushEarthquakeofJuly6,1962,PureandAppliedPhysics,62:3,81-95(1965).PandSWaveTravelTimesandSpheroidalNormalModesofaHomogeneousSphere,Jour.Geophys.Res.,71:12,2959-2965(1966).(WithJ.Oliver,A.RyallandD.Slemmons)Micro-earthquakeActivityRecordedbyPortableSeismographsofHighSensitivity,Bull.Geol.Soc.ofAmer.,56:4,899-924(1966).(WithR.C.Liebermann,C.Y.KingandP.W.Pomeroy)ExcitationofSurfaceWavesby'theUndergroundNuclearExplosionLongShot,Jour.Geophys.Res.,71:18,4333-4339(1966).F(WithC.R.Allen)AMicro-earthquakeSurveyoftheSanAndreasFaultSysteminSouthernCalifornia.,Bull,.Seism.Soc.Amer.,57:2,277-296(1967).(WithC.R.Allen)ALow-stress-drop,Low-magnitudeEarthquakewithSurfaceFaulting:TheImperial,California,EarthquakeofMarch4,1966,Bull.Seism.Soc.Amer.,57:3,501-514(1967).(WithM.Wyss)TheAlaskaEarthquakeof28March1964:AComplexHultipleRupture,Bull.Seism.Soc.Amer.,57:5,1017-1023(1967).(WithC:Y.King)ExcitationofMantleRayleighWavesofPeriod100SecondsasaFunctionofMagnitude,BulZ.Seism.Soc.Amer.,57:6,1355-1365(1967).SheFauR'Slips,EngineeringandScienceMagazine,CaliforniaInstituteofTechnology,31:2,36-38(1967).SeismicMoment,Seismicity,andRateofSlipalongMajorFaultZones,Jour.Geophys.Res.,73:2,777-784(1968).M-4
~E~iiJamesN.Brune-Bibliography28.SourceDimensionsofEarthquakesandUndergroundExplosionsofMagnitudeNear4.0,EarthquakeNotes,p.'22,(Abstract),June,1969.29.(MithC.R.Allen,A.Grantz,M.M.Clark,R.V.Sharp,T,G.Theodore,E.M.WolfandH.Myss),TheBorregoHountain,California,EarthquakeofApril9,1968:APreliminaryReport,Bull.Seism.Soc.Amer.,58:3,1183-1186(1968).30.(WithH.Myss),SeismicHoment,StressandSourceDimensionsforEarthquakesintheCalifornia-NevadaRegion,Jour.Geophys.Res.,73:14,4681-4694(1968).31.RegionalVariationsintheStructureoftheUpperMantleandthePropagationoftheSaPhase,ContinentalMarginsandislandArcs,UpperMantleComiitteeSymposium,Ottaua,Canada,-'965,GSCPaper66-15,(1969).32.SurfaceMavesandCrustalStructure,GeophysicalrVonograph,13:230-242(1969).33(WithG.R.Engen),ExcitationofMantleLoveWavesandDefinitionofYiantleWaveMagnitude,Bull.Seism.Soc.Amer.,59:2,923-933(1969).33a.34.35.Seismicity,RateofSlip,StressandHeatFlowalongtheSanAndreasFaultinCalifornia,EOSTrans.Amer.Geophys.Union,SO:5,May1969.(With'T,HenyeyandR.Roy),Heat,Flow,StressandRaveofSlipAlongtheSanAndreasFault,California,Jour.Geophys.Res.,74:15,3821-3827(1969).IE(WithM.Thatcher),HigherModeinterferenceandObservedAnomalousAppaentLoveWavePhaseVelocities,Jour.Geophys.Res.,74:27,6603-6611(1969).36.(WithH.Trifunac),ComplexityofEnergyReleaseDuringthe1'mperialValley,California,Earthquakeof1940,Bull.Seism.Soc.Amer.,60:1,137-160(1970).37~38.(WithD.Anderson,C.Archambeau,C.Richter,S.Smith),EarthquakesandNuclearDetonations,Science,167:1011-1012(Feb.13,1970).(WithW.ArbaszandG.Engen),LocationsofSmallEarthquakesNeartheTrifurcationoftheSanJacintoFaultSoutheastofAnza,California,Bull.Seism.Soc.Amer.,60:2,617-627(1970).39.TectonicStressandtheSpectraofSeismicShearWavesfromEarthquakes,Jour.Geophys.Res.,75:26,4997-5009(1970).40.SeismicSources,FaultPlaneStudiesandTectonics,EOS,52:5,178-187,Hay1971,(IUGGQuadrennialReport'nSeismologyforU.S.)
- amesN.Brune-BibliographyPDI'a'V<<2~3~(withflayneThatcher)"SeismicStudyofanOceanicRidgeEarthquake.SwarmintheGulfofCalifornia'eophps.Z.p.as0z'.Soc.,22:473-489(July,1971).(withCinnaLomnitz,F.Hooser,C.P..Allen,andW.Thatcher)"SeismicityandtectonicsofthenorthernGulfofCaliforniaRegion,Hexico.PreliminaryResults.Gee]'isicaInternacionaZ,~0:37-48,Hexico,1970."SeismicMethodsforMonitoringUndergroundNuclearExplosions,anAssessmentoftheStatusandOutlook",(BookReview)InternationalInstituteforPeaceandConflictResearch(SIPRI)Stockholm,Sweden,BuZZ.Seism.Soc.Ames'.f~(withW.Prothero,J.Dratler,B.Block)"SurfaceWaveDetectionwithaBroad-BandAccelerometer",l'/atua,23Z:,21,80-81(Hay,1971).(withJ.Davies)"RegionalandGlobalFaultSlipRatesfromSeismicity",Ei1ature,229,101-107(January,1971)."SeismicDiscriminationBetweenEarthquakesandUndergroundExolosions",statementandtestimonyatHearingsbeforeSubcommitteeonArmsConrol,InternationalLawandOrganization,Ninety-secondCongressoftheU.S.,FirstSessiononComprehensiveNuclearTestBanTreaty,139-149(July22-23,1971).rp~(withHaxWyss)"RegionalVariationsofSourcePropertiesinSouthernCaliforniaEstimatedfromtheRatioofShort-toLong-PeriodAmplitudes",Bull.Seism.Soc.Amer.,6Z,1153-1167(October,1971)."ADeploymentProgramforSeismicMonitoringofaComprehensiveTestBanTreaty",statementandtestimonyatHearingsbeforeSubcommitteeonResearch,Development,andRadiationoftheJointCommitteeonAtomicEnergyCongressoftheU.S.,Ninety-Secondcongress,FirstSessiononExtentofPresentCapabilitiesforDetectingandDeterminingNatureofUndergroundEvents,133-142(October27-28,1971).~~r~(withW.Prothero)"ASuitcaseSeismicRecordingSystem",BulZ.Seism.Scc.Amez'.,6Z,6,1849-1852(December,1971).4~(withD.McKenzie)"MeltingonFaultPlanesDuringLargeEarthquakes",Gecpnus.J.B.as'.Soc,29:1"(.1972).(withD.Oldenburg)"RidgeTransformFaultSpreadingPatterninFreezingWax,Science,Vol.178(1972)301.M-6 52.C.R.Allen,M.Myss,J.N.Brune,A.GrantzandR.E.Wallace."DisplaccmentsontheImperial,SuperstitionHills,andSanAndreasFaultsTriggeredbytheBorregoMountainEartnquake".InU.S.G.S.,Prof.Paper8787,pp.87-104(L972),53.t54.B.E.TuckerandJ.N.Brune.."Seismograms,S-WaveSpectraandSourceParametersforAftershocksoftheSanFernandoEarthquakeofFebruary9,1971."I/OAASpecialReport,1973,I.Reid,M.Reichle,J.BruneandH.Bradner."MicroearthquakeStudiesusingSonobuoys:PreliminaryResultsfromtheGulfofCalifornia."Geophys.J'.B.astr.Soc.,34,365-379(1973).55,J.N.Brune,S.delaCruz,H.Bradner,C.Villegas,I.Reid,M.Reichle,'A.Nava,M.LozadaandP.Silva."EarthquakesintheGulfofCaliforniaRecordedusingLand-BasedRecordingsofMooredHyd.ophoneArrays."GeofisicaZrit.,12(3),201-212(L972).56.J.N.BruneandC.Lomnitz."RecentSeismologicalDevelopmentsRelatingtoEarthquakeHazard."GeofisicaZnt.,14:pp.49-63(1974),"57.P.Molnar,B.E.TuckerandJ.N.Brune."CornerFrequenciesof'andSHaves8Models'oEEarthqu'akeSources,"'ull.Seismo.Soc.i'.,63,2091-2105(1973).58.59.F.Gilbert,A.DziewonskiandJ.Brune."AnInformativeSolutiontoaSeismologicalInverse.roblem".Proc.Efat'l.Acad.Sci.,70,5,pp.1410(1973.).W.ThatcherandJ.N.Brune."Surfacewavesandcrustalstructure'ntheGulfofCaliforn'iaregion."Bull.Seism.Soc.Am,63,5,1689-3.698(1973).60.Brune,J.N."Earthquakemodellingbystick-slipalongpre-cutsurfacesinstressedfoamrubber".Bull.Seism.Soc.Am.,63,.~.6.,2105-2119.(197,3).61.62.63.64.65.Brune,J.N.andF.Gilbert,"TorsionalOvertoneDispersionfromCorrela-tionsofSWavestoSSWaves",Bull.Seiam.Soc.Am.,64(2),313-320-(1974).H.BradnerandJ.Brune,"TheUseofSonobuoysinDeterminingHypocentersofAftershocksoftheFebruary21,.1973Pt.MuguEarthquake,"~l.l,.Am.,64,No..l,99-101,1974.J.N.Brune,"CurrentStatusof.UnderstandingQuasi-PermanentFieldsAssociatedwithEarthquakes",'EOS,55,No.9,1974.tD.M.OldenburgandJ.N.Brune,"AnExplanationfortheOrthogonalityofOceanRidge"and.TransformFaults",J.Geophys.Res.,80,no.17,.p.2575,1975.AlfonsoReyes,J.Brune,L.Canalcs,J,Madrid,J,Rebollar,L.Munguia,T.Barker,"AMicroearthquakeSurveyoftheSanMiguelFault,BajaCalifornia,Mexico",Geophys,Res.Lttrsp2)56593975.M-7 JamesN.Bruno-B'ographyPage1~a66,JamesBrune,CinnaLomnitz,ClarenceAllen,FredoricoHooser,FrancisIohnor,~andAlfonsoReyes,"APermanentSeismographArrayAroundtheGulfofCalifornia,"Z~li'.Soi.one.8o'~.Am.,66,969-978,1976.67.RalphArchuletaandJamesN.Brune,"SurfaceStrongMotionAssoc-atedwithaStick-SlipEventinaFoamRubberModelofEarthquakes"Bull,Soismo.Soc.Am.,65,1459-1071,1975.68.69.70.BrianE;TuckerandJ.N..Brune,"SourceHechanismandSurface-wave-ExcitationforAftershocksoftheSan,FernandoEarthquake",Geophys.J.R,astr,Soc,,4937>~426)>977r.HichaolReichle,GeorgeSharman,andJamesBrune,"SonobuoyandTeleseismicStudyofTwoGulfofCaliforniaTransformFaultEarthquakeSequences",Bull.Seisrrio.Soc.Amer.,66,1623-1642,1976.'illiamA'.Prothero.,IanReid,MichaelReichle,JamesBrune,'Ocean-BottomSeismicMeasurementsontheEastPacificRiseandRiveraFractureZone",Nature,262,121-124,1976.71.GeorgeF.SharmanrMichaelSrReichle>James.N,Brune,"ADetailedStudyofRelativePlateHotionintheGulfofCalifornia,"Geology,April;pp.206-210$1976.II72.StephenH.HartzellandJamesN.Brune,"SourceParametersfortheJanuary>1975Brawley-ImperialValleyEarthquakeSwarm"PAGEOPH,1151977.73.JamesN.Brune,AlfonsoReyes,MichaelS.Reichle,"RecentSeismicand'TectonicStudiesoftheGulfofCalifornia",CIBCASIOAnnualReport,1976.74.75..76.JamesN.Brune,R.Archuleta,J.Frazier,G.Hegemier,"PhysicalandNumericalModelingofSpontaneousSlip",sugaryoftalkgivenatNorthwesternUniversityatNSFWorkshopon"ApplicationofElasticWavesinElectricalDevices,Non-DestructiveTestingandSeismology"Hay24-26,1976.1JamesN.Brune,"QofShearWavesEstimatedfromS-SSSpectralRatios,"Geophys.Res.Lttrs.,4,No.5,1977.Stephen.H.Hartzell,GeraldA.FrazierandJamesN.Brune,Earthquakemodelinginahomogeneoushalf=space,r'ull.Seism.Soc.A'm.,68,301-316,'978.77.KeithPriestleyandJamesN.Brune,"SurfaceWavesandtheStructureoftheGreatBasinofNevadaandWesternUtah",acceptedforpubli-cation,1977.78.LuisMunguia,M,Reichle,A.Reyes,R.Simons,J.N.Brune,"Aftershocksofthe8July1975CanalDeLasBallenas,GulfofCalifornia,Earthquake",Geaphysical'es.Lttr.',4,No.11,1977.M-8:
79,J.N.Brune,"implicationsofEarthquakeTriggeringandRupturePropa-gationforearthquakePredictionBasedonPremonitoryPhenomena",presentedatUSGSConferenceonFaultMechanicsanditsRelationtoEarthquakePrediction,December1-3,1977.80.J.N.Brune,R.J.ArchuletaandS.H.Hartzell,"Far-FieldS-WaveSpectra,CornerE'requenciesandPulseShapes",presentedatUSGS'onferenceonFaultMechanicsanditsRelationtoEarthquakePredictionDecember1-3,1977..81.StephenHartzell,JamesN.BruneandJorgePrince,"TheOctober6,1974AcapulcoE'arthquakeandtheimportanceofShortPeriodSurfaceWavesinStrongGroundi~fotion,inpreparation,1978.82.JamesN.Brune,"StatementtotheACRS"meetfhSbmeetingoteSubcommitteeoftheAdvisoryCommitteeonReactorSafeguards,LosAngelesCalifos,aornia,83.StephenHartzellandJamesN.Brune,"AnalysisoftheBucharestStrongGroundMotionRecordfortheMarch4,1977RomanianEarthquake",inpreparation,1978.84.A.Reyes,J.N.BruneandC.Lomnitz,"SourceMechanismandAftershockStudyoftheColima,MexicoEarthquakeofJanuary10,1973",inpre-paration,1978.85.StephenHartzellandJamesN.Brune;"TheHorseCanyonEarthcuakeofAugust2,1975-TwoStageStressReleaseProcessinaStrike-SlipEarthquake",inpreparation,1978.M-9
~k~
~~ATTAIEI<TNCurxiculumVitaeforJ.EnriqueLucoBirthDate:May18,1943-VinadelMar,ChileEducation:WScientificResearch:Ph.D.UniversityofCalifornia,LosAngeles-1969.CivilEngineer,UniversityofChile,Santiago-1967.Includesstudiesontheeffectsofgeologyandlocalsiteconditionsonearthquakegroundmotion;dynamxcresponseo~zoundaticns;"oil-str"ct~rcinteractionduringearthquakes;wavepropagationonasimplifiedmodeloftheEarth;evaluationofearthquakedamage;earthquakeresponseofnuclearpowerplants;forcedvibxationsofstructures.Employment;AssociateProfessorofAppliedMechanics,UniversityofCalifornia,SanDiego,1977<<present.AssistantProfessorofAppliedMechanics,UniversityofCalifornia,SanDiego,1974-1977.SeniorResearchFellowinAppliedScience,CaliforniaInstituteofTechnology,'973-1974.Researcher,DepartmentofGeophysics,UniversityofChile,1970-1973.ProfessorintheDepartmentsofMathematicsandPhysics,UniversityofChile,1971-1972.ResearchFellowinAppliedSciences,CaliforniaInstituteofTechnology,1970.ResearchAssistant,DepartmentofGeophysics,UniversityofChile,1965-1967.ProfessionalSocietiesMembership:AmericanSocietyofCivilEngineers.Seismo)ogicalSocietyofAmerica.Am'ericanAcademyofMechanics.SigmaXl, PublicationsofJ.E.'Lucol.1967.ProaationofHih-FreuencComressionalPulsesinaLaeredSphere,CivilL'ngincerThesis,FacetteddeCienciasFisicasyMatematicas,UniversidaddeChile,Santiago,Chile(PublicationNo.45,DepartmentofGeophysics,UniversityofChile,Santiago).2.1969."DynamicInteractionofaShearWallwiththeSoil,"J.EngineeringMechs.Div.,ASCE,Vol.95,No.EM2,April,pp.333-346..3.1969.AlicationofSingularInteralEuationstotheProblemofForcedVibrationsofaRiidFoundation,Ph.D.Dissertation,SchoolofEngineeringandAppliedScience,UniversityofCalifornia,LosAngeles.(December).~4.1970."DynamicSoil-StructureInteraction,"withHradilek,P.J.,InformeTecnicoNo.14InstitutodeInvestigacionesEnsaesdeMateriales(IDIEM),UniversidaddeChile,Santiago,Chile.5.1970."StrongEarthquakeMotionandSiteConditions:Hollywood,"withDuke,C.M.,Carriveau,A.R.,Hradilek,P.J.,Lastrico,R.,andPstrom,D.,Bull.SeismeSoc.Amer.,Vol.60,No.4,August,pp'.1271-1289.6.1971."DynamicResponseofCircularFootings,"withWestmann,R.A.,EngineeringReportNo.7113,SchoolofEngineeringandAppliedScience,UniversityofCalifornia,LosAngeles(April).7.'971."DynamicResponseofCircularFootings,"withWestmann,R.A.,J.EnineerinMechs.Div.,ASCE,Vol.97,No.EM5,October,pp.1381-1395.8.1971."InformePreliminar,sobreIntensidadesyDanoscausadosporelSismode8deJuliode1971:ZonaCalera-Illapel,"withLastrico,R.,andMedone,C.A.,RevistaGeografica,deChile,No.21,pp.14-19,Santiago,Chile.9.1972."APreliminaryReport,TheJuly8,1971ChileanEarthquake,"withEisenberg,A.,andHusid,R.,Bull.SeismeSoc.Amer.,Vol.62,No.1,February,pp.423-430.10,1972.DynamicResponseofaRigidFootingBondedtoanElasticHalf-Space,"withWestmann,R.A.,J.Al.Mech.,ASME,Vol.39,SeriesE,No.2,June,pp.527-534.N-2
~~a~ll,.1972."ElTerremotodeSanFernandoenCalifornia,"withLastrico,R.,RevistadelaConstruccion,AnoXI,No.117,Junio-Julio,Santiago,Chile.12.1972.rr~~rr"IngenieriaSismicaenChile:unaBibliografia,"InformeTecnicoNo.15,InstitutodeInvestigacionesEnsaesdeMateriales(IDIEM),UniversidaddeChile,Santiago,Chile.13.1973."DynamicStructure-Soil-StructureInteraction,"withContesse,L.,Bull.Seism.Soc.Amer.,Vol.63,No.4,August,pp.1289-1303.14.1973."VibracionesHorizontalesdeunDiscoRigidosobreunSemiespacioElastico,"RevistadelInstitutodeInvestizacionesEnsavesdeMateriales(IDIEM),Vol.12,No.1,pp.1-13,UniversidaddeChile,Santiago,Chile.15.1974."Soil-StructureInteraction-ContinuumorFiniteElement","withTsai,N.C.andHadjian,A.H.,NuclearEn~ineerinandDesign,Vol.31,No.2,pp.151-167.16,1974."TheDynamicModelingoftheHalfPlanebyFiniteElements,"withBos,H.,andHadjian,A.H.,NuclearEnineeringandDesign,Vol.31,No.2,pp.184-194.17.1974."Two-DimensionalApproximationstotheThree-DimensionalSoil-StructureInteractionProblem,"withHadjian,A.H.,NuclearEnineerinandDesi,Vol.31,No.2,pp.195-203,18.1974."ImpedanceFunctionsforaRigidFoundationonaLayeredMedium,"NuclearEnineerineandDesign,Vol.31,No.2,pp.204-217,19.1975."FullScale,ThreeDiiYlensio.alTesoStrctr1DeormationsDuringForcedExcitationofaNine-StoryReinforcedConcreteBuilding,"withFoutch,D.A.,Tzifunac,M.D.,andUdwadia,F.E.,ProcecdinsU.S.Nation"1ConferenceonEarthquake920.1975."AnExperimentalStudyofGroundDeformationsCausedbySoilStructureInteraction,"withTrifunac,M.D.,andUdwadia,F.E.,ProceedingsU.S.NationalConferenceonEarthuakeEn~ineerinJune,1975,AnnArbor.21.1975."ANoteontheDynamicResponseofRigidEmbeddedFoundations,"with%'ong,H.L.,andTrifunac,M.D.,EarthquakeEngineeringandStructuralDynamics,Vol.4,No.2,pp,119-128.
22.1975."DynamicModelingofaViscoelasticHalf-SpacebyFiniteElements,"withHadjian,A.H.andAtalik,S.,ProceedingsSecondASCEConferenceonStructuralDesinofNuclearPlantFacilities,December,1975,NewOrleans.23.1976."TorsionalResponseofStructurestoObliquelyIncidentSHWaves,"EarthuakeEnineeringandStructuralnamics,Vol.4,No.3,January-March,pp.207-219.24.1976."TorsionalResponseofStructuresforSH-Waves:theCaseofHemisphericalFoundations,"Bull.Seism.Soc.Amer.,Vol.66,No.1,February,,pp.190-123.25.1976.",VibrationsofaRigid'DisconaLayeredViscoelasticMedium,"NuclearEnineeringandDesin,Vol.36,No.3,March,pp.325-340.26.1976."TorsionofaRigidCylinderEmbeddedinanElasticHalf-Space,"JournalofApliedMechanics,Vol.43,SeriesE,No.3,September,pp.419-423.27.1976."DynamicResponseofRigidFoundationsofArbitraryShape,"withWong,H.L.,EarthIakeEngineeringandStructural6,*-*..9-928,1976."TorsionalResponseofaRigidEmbeddedFoundation,"withApsel,R.J.,J.oftheEn@re.Mech.DivesASCE,Vol.102,No.EM6,December,pp.957-970.29.1977."DynamicResponseofRectangularFoundationsforRayleighWaveExcitation,"withWong,H.L.,ProceedingsoftheSixthWorldConferenceonEarthuakeEngineering,NewDelhi,India.30,1977."OntheImportanceofLayeringontheImpedanceFunctions,"withHadjian,A.'H.,ProceedingsoftheSixthWorldConferenceonEarthuakeEngineerin,NewDelhi,India.31.1977."ContactStressesandGroundMotionGeneratedbySoil-StructureInteraction,"withWong,H.L.andM.D.Trifunac,EarthqualceEnineerinzandStructuralnamics,Vol.5,No.1,January-March,pp.67-69.32.1977."TheApplicationofStandardFiniteElementProgramsinthe'AnalysisofSoil-StructureInteraction,99withWong,H.L.,Proc.oftheSecondSAPUser'sConference,UmversitofSouthernCalifornia,June1977,LosAngeles.
~~l~EI~I33.1977.34.1978."SeismicResponseofaPeriodicArrayofStructures,"withMurakami,H.,Z.oftheEngrg,Mechs.Div.,ASCE,Vol.~103No.EM5,Oct.>pp.96~-977.r"DynamicResponseofRectangularFoundationstoObliquely"itEnineerinandStructuralDamies,Vol.6,Zan.,pp.3-16.N-5
"~hi,P~
~'~~~ATTNEHT0CURRICULUM.VITAEFORiVIIHAILOD.TRIFUNACBirthDate:ggG]75787November1942K'kinda,YugoslaviaEd"caon:Pn.D.Califor.iInst'tuteofTe"hnology,CivilEnginee"ingandGeophysics,1969M.S.Princeton.University,CivilEngineering,1966B.S.UniversityofBelgr-de,CivilEngineering,1965ScientificResearch:Includesinvestigaionofstrongearthquakeground.motionsfollowingParkfield,California,1966earthquake(1967+);high-frequencyresolutionandstrong-motionmechanismstudyofImperialValley,California19-"0earthquake(1968+);siznplemathematicalmodelsofanalluvialvalleysubjecttostrongearthquakemotion(1968+);ambientandforcedvibrationstudiesofseveralmulti-storystructures(1968+);laboratoryevaluation'nd,instrumentcorrectionmethodsofstrongmotionaccelerogzaphs()970+);developmentofthedataprocessingmethodsofstrong-motionaccelerograms(1970+);satisticsandtriggeringmech"nismofearthquakes(1968+);studiesofmicrotremorvibrationstheImperialValley(1970+);studyofnetmethodsforsynthesizingartificialstronggroundzwotion(1970+);investgationofthesoil-structureinteraction(1970+);amplificationand.focusingeffectsincomplicatedgeologicstructures(1971+);stressestimatesand.sourcemechanismstudiesofearthquakesbased,ontherecordedstrong-motionaceelexograms(1971);developmentofseismicdesigncriteria.intermsofrespozisespectra(1975+);developr.entofapproximatescalingmethodsfozstrongearthquakegroundmotonintermsofpeakaccelerations,velocitiesanddispla'ements(1975+);studiesondurationofstrongeathquakegroundmot'on(1974+);soil-bridge-soilinteraction'roblems(1975+);soil-structure-soil.-structureinteractionproblezns(1975+).~l~~~pro>c:nOvC~ggg,LgbpillCCIp)Qp$J0p+pgg~Qp(.JJQ)Q~/Oft(l(I(0ssistantProfessorofAppliedS'cience,Calif'orniaInstituteofTechnology,1972-l'l')~ResearchAssociate,Lamo..t-DohertyGeologicalObservatoryandLecturerintheDepartmentofGeologyofColumbiaUniversity,1971-1972ResearchScientist,Lamont-DohertyGeologicalObservatoryofColumbiaUniversity,1970-1971ResearchFel'o.v'..nAppliedlvlechanics,CaliforniaInstituteofTechnology,July1969-September19700-1 i~~tM.D.TrifunacCurriculumVitaePageTv'oResearchAssistant,CaliforniaInstituteofTechnology,1966-1969ResearchAssistant,PrincetonUniversity,1965-1966ConsultanttoAdvisoryCommitteeonReactorSafeguards,1971-ProfssionalSocieties:AmericanGeophysicalUnionAmericanSocietyofCivilEngineersSeismologicalSocietyofAmericaSigmaXiEarthquakeEngineeringResearchInstituteTeaching~Experience:Caltech:-2.4,ColumbiaUniversity:l..3'Ij6940y'-Strong-MotionSeismology(1971-72)CE180-ExperimentalMethodsinEarthquakeEngineeringCE181-PrinciplesofEarthquakeengineeringCE1S2-Structura1.DynamicsofEarthquakeEngineeringOtherSelectedActivitiesandEwmerience:ServedonthePanelonStrong-MotionSeismology,Committee'nSeismology,'at.Acad.ofSciences;Participated.inUNESCOSymposiumofExpertsonStrong-MotionSeismology;Participated,inATC-3effortforimprovementofEarthquakeResistantDesignCode;Presentedover50scientificpapersduringnationalandinternationalconferences.0-2
~,g~~~~'~ScientificPublicationsof.M.D.Txifunac1.1967Z.19693.1969Analysisofaccelerograms-Parkfieldearthquake,withG.W.Housner,Bull.Seism.Soc.Amer.,57,1193-1220.'IAnalysisofstrong-motionaccelerographrecords,withD.E.HudsonandN.C.iXigazn,FourthWorldConferenceonEarthquakeEngineering,Santiago,Chile.Strong-motionearthquakeaccelerograms,digitizedandplotted.data,Vol.I,withD.E.HudsonandA.G.Brady,EarthquakeEngineeringResearchLaboratory,EERL70-20,CaliforniaInstituteofTechnology,Pasadena.4.1969Investigationofstxongeaxthquakeground'motion,EarthquakeEng.Res.Lab.,Calif.Inst.ofTech.,Pasadena.5.1970AnalysisofthestationNo.2seismoscoperecord-1966,Parkfield,California,earthquake,withD.E.Hudson,Bull.Seism.Soc.Amer.,60,735-794.6.19707.1970Windandmicrotremorinducedvibrationsofa22-storysteelframebuilding,EarthquakeEng.Res.Lab.,EERL70-.01,Calif.Inst.ofTech.,Pasadena.Complexityofenergyrelease.duringtheImperialValley,California,,earthquakeof1940,withZ.N.Brune,Bull.Seism.Soc.Amer.,60,137-160.8.1970Ambientvibrationtestora39-storysteelframebuilding,EarthquakeEng.Res.Lab.,EERL70-02,Calif.Inst.ofTech.,Pasadena.9.1970Onthestatisticsandpossibletriggeringmechanismofearth-quakesinSouthernCalifornia,EarthquakeEng.Res.Lab.,EERL70-03,Calif.Inst.'fTech.,Pasadena.10.1970Laboratoryevaluationandinstrumentcoxrectionsofstrong-motionaccelerographs,EarthquakeEng.Res.Lab.,EERL70-04,Calif.Inst.ofTech.,Pasadena.11.1970Responseenvelopespectrumandinterpretationofstrongearth-quakegroundmotion,EarthquakeEng.Res.Lab.,EERL70-06,Calif.Inst.ofTech.,Pasadena..12.1970Lowfrequencydigitizationerrorsandanewmethodforzerobaselinecorrectionofstrong-motionaccelerograms,EarthquakeEng.Res.Lab.,EERL70-07,Calif.Inst.ofTech.,Pasadena.0-3 1971IResponseenvelopespectrumandinterpretationofstrongearth-quakegroundmotion,Bull.Seism.Soc.Amer.,~61343-356.14.197115.1971Zerobaselinecorrectionofstrong-motionaccelerograms,Bull.Seism.Soc.Amer.,61,1201-1211.Amethodforsynthesizingrealisticstronggroundmotion,BulL.Seism.Soc.Amer.,~611755-1770.16.1971Surfacemotionofasemi-cylindricalalluvialvalleyforincidentplaneSHwaves,Bull.Seism.Soc.Amer.,61,1739-1753.17.1971AnalysisofthePacoimaDamaccelerogram,SmFernando,California,earthquakeof1971,withD.E.Hudson,Bull.Seism.Soc.Amer.,~611393-1411.18.1971191971Highfrequencyerrorsandinstrumentcorrectionsofstrong-motionaccelerograms,withF.E.UdwadiaandA.G.Brady,EarthquakeZng.Res.Lab.,EERL71-05,Calif.Inst.ofTech.,Pasadena.Strong-motionearthquakeaccelerograms,II,correctedaccelero-gramsandintegratedvelocity,anddisplacernentcurves,withD.E.Hudson,.A.G.BradyandA.'ijayaraghavan,EarthquakeZng.Res.Lab.,EERL71-51,Calif.Inst.ofTech.,=Pa,sadena.20.1971EngineeringfeaturesoftheSanFernandoearthquake,February9,1971,ChapterII,editedbyP.C.Jennings,.EarthquakeEng.Res.Lab.,"ZERL71-02,Calif.Inst.ofTech.,Pasadena.21.1972=Strong-motionaccelerograms,III,responsespectra,withD.E.HudsonandA.G.Brady,Earthqua.keEng.Res;Lab.,EERL72-80,Calif.Inst.ofTech.22.1972Strong-motionearthquakeaccelerograms,IV,Fourierspectra,withD.E.Hudson,F.E.Udwadia,A.Vijayaraghavan,andA.Brady,EarthquakeEng.Res.Lab.,ZERL72-100,CalU.Inst.ofTech.,Pasadena.23.1972InteractionofashearwallwiththesoilforincidentplaneSH.waves,Bull.Seism.Soc.Amer.,62,63-83.24.1972Anoteoncorrectionofstrong-motionaccelerogramsforinstrumentresponse,Bull.Seism.Soc.Amer.,~62401-409.25.1972StressestimatesforSanFernando,California,"earthquake.of9February1971:itineventandthirteenaftershocks,Bull.Seism.Soc."Amer.,62,721-750.26.1972TectonicstressandsourcemechanismoftheImperialValley,California,ea,rthquakeof1940,Bull.Seism.Soc.Amer.,~621283-1302.0-4
~/0'ompaxisonbetweenambientandforcedvibrationexperiments,Int.J.ofEarthquakeEng.andStruct.Dynamics,~l133-150.$",ud:esofstrongearthquakemotionsandmicrotremorprocesses,withF.E.Udhvadia,'InternationalConf.ofi>iicrozonation,Seattle,Washington.Analysisoferrorsindigitizedstrong-motionaccelexograms,withF.E.Udwadia,andA.G.Brady,Bull.Seism.Soc.Ame'r.,o3,157-187.AnoteonscatteringofplaneSICwavesbyasemi-cylindricalcanyon,Int.J.ofEarthquakeEng.and,Struct.Dynamics,~1267-281.Characterizationofresponsespectrabyparametersgoverningthe'rossnatureofearthquakesourcemechanism,53VCEE,Rome,Italy.Recentdevelopmentsindataprocessingandaccuracyevaluationsofstrong-motionaccelerationmeasurements,withF.E.UdwadiaandA.G.Brady,5V;CEE,Rome,Italy.--Ambientvibrationtestsoffull-scalestructures,withF.E.Udwadia,577CEE,Rome,Italy.ComparisonofearthquakeandmicrotremorgroundmotionsinElCentro,California,withF.E.Udwadia,Bull.Seism.Soc.Amer.~63iso.4,1227-1253.Analysisofstron~earthquakegroundmotionforprediction-ofresponsespectra,Int.J.ofEarthquakeEng.andStruct.Dynamics,Vol.2,No.1,59-69.TheFouriertransform,responsespectxaandtheirrelationshipthroughthestatisticsofoscillatorresponse,withF.E.Udwadia,EarthquakeEng.Res.Lab.,EERL73-01,Calif.Inst.ofTech.DampedFourierspectrumandresponsespectra,withF.E.Udwadia,Bull.Seism.Soc.Amer.,63,1775-1783.Routinecomputerprocessingofstrong-motionaccelerograms,withV.Lee,EarthquakeEng.Rcs.Lab.,EERL73-03,Calif.Inst.ofTech.Characterizationofresponsespectrathroughthestatistics.ofoscillatorresponse,with1".E.Udwadia,Bull.Seism.Soc.Amer.,~64205-219.Athree-dimensionald'slocationmodelfortheSanFernando,California,earthquakeofFebruary9,1971,Bull.Seism.Soc.Amer.,64,149-172.0-5 41..1974Parkfield,California,earthquakeofJuneZ7,'966:athree-dimensionalmovingdislocation,withF.E.Udwadia,Bull.Seism.Soc.Amer.,64,511-533.4Z.1974Timeandamplitudedependentresponseofstructures,withF.E.Udwadia,Intl.J.ofEarthq.Engr..andStruct.Dyn.~2359-378.43.97AAnoteontheaccuracyofcomputedgrounddisplaceznentsfroznstrongmotionaccelerograms;withV..W.Lee,Bull.Seism.Soc.Amer.,64,1209-1Z19.44.1974VariationsofstrongearthquakegroundshakingintheLosAngelesarea,withF.E.Udwadia,Bull.Seiszn.Soc.Amer.,641429-1454.45.1974ScatteringofplaneSH-wavesbyasezni-ellipticalcanyon,withH.L.Wong,Intl.J.ofEarthquakeEngr.andStruct.Dyn.,~3157-169.46..1974Surfacemotionofasemi-ellipticalaQuvialvalleyforincidentplaneSH-waves,withH.L.Wong,Bull.Seism.Soc.Azner.,64,1389-1408.47.1974InteractionofashearwallwiththesoilforincidentplaneSHwaves:ellipticalrigid-foundation,wthH.L.Wong,Bull.Seism.Soc.Amer.,~641825-1842.48.1975Anarrayof.strongznotionaccelerographsinBearValley,California,withR.J.DielznanandT.C.Hanks,Bull.Seism.Soc.Amer.,~65l-lZ.49.1975Anoteonthedynamicresponseofrigid,embeddedfoundations,withJ.E.Lucoand'.L.Wong,submittedtoIntl.J.ofEarthquakeEng.andStruct.Dyn.50.1975Onthecorrelationofseismicintensityscaleswiththepeaksofrecorded,strongground.motion,withA.G.Brady,Bull.Seism.Soc.Amer.,65,139-162.51.1975OnthecorrelationofseismoscoperesponsewithearthquakemagnitudeandModifiediviercalliintensity,.withA.G.Brady,Bull.Seism.Soc.Azner.,65,307-321.52.1975Astudyonthedurationofstrongearthquakegroundmotion,withA.G.Brady,Bull.Seism.Soc.Amer.,65,581-626.53.1975Two-dimensional,antiplane,building-soil-buildinginteractionfortwoormorebuildingsandforincidentplaneSH-waveswithH.L..Wong,submittedtoBull.Seism.Soc.Amer.0-6 Correlationsofpeakacceleration,velocityanddisplacementwithearthquakemagnitude,distance,andsiteconditions,withA.G.Brady,Intl.Z.ofEarthquakeEngr.andStruct..Dyn.(inpress).Onthecorrelationofpeakaccelerationsofstrongmotionwithearthquakemagnitude,epicentraldistanceandsiteconditions,withA.G.Brady,Proc.U.S.NationalConferenceonEarthquakeEngineering,AnnArbor,Michigan,43-52.Preliminaryanalysisofthepeaksofstrongearthquakegroundmotion-dependenceofpeaksonearthquakemagnitude,epicentraldistanceandtherecordingsiteconditions,Bull.Seism.Soc.Amer.(inpress).t.ullscale"three-dimensionaltestsofstructuraldeformationsduringforcedexcitationofanine-storyreinforcedconcretebuildng,withD.A.Foutch,Z.E.Luco,andF.E.Udwadia,Proc.U.S.NationalCo'nferenceonEarthquakeEngineering,AnnArbor,Michigan206-215.Anexperimentalstudyofgrounddeformationscaused,bysoil-structureinteraction,withZ.E.LucoandF.E.Udwadia,Proc.U.S.NationalConferenceonEarthquakeEngineering,AnnArbor,Michigan,136-145.Influenceofacanyononsoil-structureinteraction,withH.L.AVong,J.Engr.Mech.Div.,ASCE(inpress).Antiplanedynamicsoil-bridge-soilinteractionforincidentplaneSH-waves,withA.M.Abdel-Ghaffar,Intl.Z.ofEarthquakeEng.andStructuralDyn.(inpress).pAnoteontherangeofpeakamplitudesofrecordedaccelerations,velocitiesanddisplacementswithrespecttotheModifiedMercalliintensity,EarthquakeNotes(inpress).Contactstressesandgroundmotiongeneratedbysoil-structureinteraction,withH.L.WongandJ.E.Luco,submittedtoIntl.Z.ofEarthquakeEng.andStruct.Dyn.Preliminaryemoiricalmodelforscalingcourieramplitudespectraofstronggroundaccelerationintermsofearthquakemagnitude,sourcetostationdistanceandrecordingsiteconditions,Bull.,Seism.Soc.Amer.(inpress)..Dependenceofdurationofstrongearthquakegroundmotiononmagnitude,epicentraldistance,geologicconditionsattherecordingstationandfrequencyofmotion,withB.Westermo,submittedtoBull.Seism.Soc.Amer.0-7
~i~~65.1976Onthecomparisonofexperimentalandtheoreticalanalysesoftheeffectsofsurfaceandsubsurfaceirregularitiesontheamplitudesofmonochromaticwaves,withH.L.WongandB.Westermo,submittedtoBull.Seism.Soc.Amer.66.1976CorrelationsoffrequencydependentdurationofstrongearthquakegroundmotionwiththeModifiedMercalli.Intensityandthegeologicconditionsattherecordingstations,withB.Westermo,submittedtoBull.Seism.Soc.Amer.67.1977'ninstrumentalcomparisonoftheModifiedMercalli(M.M.l.)andMedvedev-Karnik-Sponheuer(M.K.S.)Intensityscales,SixthWorldConf.EarthquakeEngineering,NewDelhi,India.68.1976Effectsofcross-axissensitivityandmisalignmentonthexesponseofmechanical-opticalaccelerographs,withH.L.AVong,submittedtoBull.Seism.Soc.Amer.69.1977Antiplanedynamicsoil-bridge-soilinteractionforincidentplaneSHwaves,withAbdel-Ghaffar,SixthworldConferenceEarthquakeEngineering,NewDelhi,India.70.1977Statisticalanalysisofthecomputedresponseofstructural'responserecorders(S.R.R.)foraccelerogramsrecordedintheUnitedStatesofAmerica,SixthworldConferenceEarthquakeEngineering,NewDelhi,India.0-8 I~/JI~I'~~f'Ifls]i~orro~,~o~~*~s~l~~~~ATTACHMENTP~~REYIG'fOFTllE'SEIShlICEYALUATIONFOR~POSTULATED7.5hfIlOSGRIEARTNQUA}:E,UNITSlAND2,DIABLOCANYONSITE'yJ.EnziqueLucoARcporttotheAdvisoryCommitteeonReactorSafeguardsU.S.NuclearRegulatoryCommission.I~150hhy1978 REYIEIfANDRECONlENDhTIONSAfterdctailcdreviewofthcrcport'SeismicEvaluationforpostulated7.5~ifllosgriEarthquake'Rcf.1),.Ihavethcfollowingcommentsandrccommcndations:l.Frcc-FieldDesi.nSncctrum.Inmyopinion,thefrcc-fielddesignspectrumusedforrc-evaluationofthcDiabloCanyonNuclearPowerPlantdocsnotreflectthestrongmotionatthcsitefora7.5magnitudeearthquakeatanepicentraldistanceof5kilometers,butratherthemotionfora6.Sicearthquakeatthatdistance.Thefree-fielddesignspectrumdevelopedbyNewmarkandadoptedbyNRCcorrespondstoasimplifiedversionoitheaverageofthetwoPacoimaDamspectrarecordedduringthe6.5A'anFernandoearthquakewiththehigh-frequencyportionreducedbyuseof'n'effective'eakacceleration(Fig.1).ThcBluntsdesignspectrumdevelopedfortheapplicantcloselyfollowstheNewmarkspectrum.Thepeal;acceleration,velocityanddisplace-I'entcontrollingthehigh,intc'rmcdiateandlowircqucncyportionsofthcNcwmarkdesignspectrumarcinagrccmcntwiththeaverage(50'ercentile)peakvaldcsobtainedbyTrifunac(Ref.2)forah6.5htearthquakewhilefallingshortby40to60percentfromthecorrespondingvaluesfora7.5hfearthquake(Table1).ThepeakvaluesconsistentwiththcNcwmarkspectrumarcalsoconsiderablylowerthanthose'suggcstcdinUSGScircular672(Rcf..3)asshowninTable'1.Inaddition,comparisonofthcNcwmarkandBlumcdc-signspectrawithcstimatcsofthcavcragcrcsponscspectrumforqo~~~I~~P-2I
~n'~a7.5)4carthquakcasobtainedbyTrifunac(Rcf.4)alsoshowsdiffcrcnccsofthcorderoi30to50pcrccnt(Fig.2).Theapplicanthasindicatedthatthcthrustfaultmech"nismandthclocationofthePacoimaDaminstrumentinthcSanFernandoearthquakemayhaveincrcascdthcrecordedpeakacccl-eration.Thesepossiblecficctsarcncgligiblcinviewofthcfactthatthestandarddeviationforpeakaccclcrations,whichhas,notbeenconsidered,correspondstoafactorof2.Also,thcrecordsiorthchfs=7.2Gazli,Russiaearthquakeof1976indicateapeakhorizontalaccelerationof0.8gatanepicentraldistanceof10kilometers.CorrectingforattenuationusingtheGutenberg'srelationleadstoapeakaccelerationof1.0gat5kilometersforthcGazliearthquakeingeneralagrcemcntwiththeresultsofTrifunacandthcUSGSrccommcndation(Table1).Xnviewofthesefacts,Imust,concludethatthcNcwmarkandBlumcdesignspectradonotcorrcspondtothegroundmotionfora7.5'arthquakeatanepicentraldistanceof5kilometers.Ipro-posethattheestimateoftheaverageresponsespectrumfor51=7.5,5kilometers,epicentraldistanceandrocksitesofTrifunac(Rcf.4)bcusedasdesignspectrum.Thisspectrumisconsistentwiththconlyrecordsavailablcforlargemagnitudeandshortepiccn-traldistances(SanFernando,KoynaandGazli)aswellaswiththcUSGScircular672rccommcndations.2~'Efi'cctivc'eakAcceleration.Ajudgmentaliactorhasbccnusedtorcduccthc1.15gpeakaccclcrationrccommcndcclinUSGScircular67toavalueoC.0.75g.Thisill-dcCincdCactorCP-3 ethasbccnusedinthcpasttoaccountfordiscrcpancicsonthclevelofdamageobscrvcdascomparedwiththcprcdictionofordinaryseismicanalyseswhichdonotaccountforthceffectsofsoil-structureinteraction,arebasedonnominalvaluesfordamp-ingandstrength,assumelinearbehavioura>>ddonotincludetheenergydissipationinpartitionsandothernon-structuralclc-ments.Thiscatch-allreductionfactor.hasnoplaceinthede-signofcarefullyanalyzedstructuressuchasthosexnnuclearpowerplants.Factorswhichmayreducetheresponseorthclevelofdamageshouldbeidentifiedandproperlyincludedinthcstruc-turalmodels.InthecaseofDiabloCanyon,manyofthesefactor.havealreadybeenincorporatedinthcanalysis:useoftc-tstrengthratherthannominalvalues,useofhigherthancommon~dampingvalues,reductionbyscatteringofwavesbylargefounda-tionsandpossibleinclusionofductility.Thcarbitraryreductio.-.ofthehigh-frequencycomponentsofmotionaffectstheresponsepipingandequipment.Irecommendthe.eliminationofthisreduc-tionoftheinputmotion.3.OnthcEffectofScatteringofNavcsbRic.idFoundations.Thchigh-frcquc>>cycomponentsofthefree-fieldmotionhavebeenreducedbythcso-calledtau-filteringproceduretoaccountbythescatteringofwavesbythcsupposedlyrigidfoundations.ThiscorrectionamountstoareductionoftheNcwmarkfree-fielddesignspectrumby20to30pcrccntforfrcqucncicshigherthan2cps.SlightlylowerreductionshavebccnusedinthcBlumc'sspectrum.Thccorrectionforfoundationscatteringeffectsisbasedonthc~~~~gP-4 assumptionofarigidfoundationandhorizontallypropagatingSllwaves.Althoughthca"sumptionofarigidfoundationmaybcrca-sonablc,itmustberccognizcdthatdeviationsfromthcassumptionleadtolocalizedhigherstressesinthclowerportionsofthcdiffcrcntstructures.TheassumptionofhorizontallyincidentSflwavesishighlyquestionableconsideringthatthcepicentraldis-tancciscomparablewiththefocaldepth.Underthcscconditions,thepossibilityofnearlyverticallyincident.wavesmaynotbcruledout.Forverticallyincidentwavesthescatteringbythefoundationsispracticallynonexistentgiventhcshallowembed-ment.Assumingforthesakeoftheargumentthattheseismicexci-tationatthcsitecorrespondsx~horizontallyincidentSllwaves,IfindthatthcreductionsproposedbyNcwnarkandBlumcarctoohighwhencomparedwithanalyticalsolutions.Forhori"ontallyincidentSllwavesthereductionofthctranslationalcomponentsofmotioniscoupledwiththcpxistenccofamarkedtorsionalinputtothestructure(fordetailsrefertotheattachedpapers).Theapplicanthasincluded'accidental'ccentricitiesof5and7percenttorepresentthesetorsionaleffects.Theuscofaneccentricityof5percentcorrespondstothcuseofapeaktor-sionalaccelerationatthcbaseofthccontainmcntofthcorderof0.025rad/scc2asmaybcinfcrrcdfromTable4-5ofPcf.'1.Thistorsionalaccclcrationcorrespondstoatangentialaccclcr"ationatthcbaseofthccontainmcntcxtcrior.of0.025x70/52=0.05g.ThcresultsofRayandJhavcriofURS/131umcprcscntcdin
~P~Fig.56ofAppendixD39A,butnotusedinthcanalysis,showthatapeaktorsionalaccelerationofthcorderof0.1rad/scccorrcs-2pondingtoapeaktangentialaccclcrationatthcbaseofthccon-tainmcntexteriorof0.2g'wouldbemorcappropriate.Itmaybcconcludedthatthcuseofa5percenteccentricityundcrcstimatcsthctorsionalinputbyafactoroffour.Thisob"crvationiscon-sistentwiththeoriginalworkofNcwmark(Ref.5)whichindicatesthataneccentricityoftheorderof25percentwouldbcnecessarytorepresentthetorsionaleffectsinducedbyhorizontallypropa-gatingSllwaves.Itmustbementionedthatthcincreaseinpeakaccelerationof0.2gbasedonamorerealisticestimateofthetorsionalinputmorethancompcnsatcsforthcreductionbytau-filteringfrom0.75gtoO.G7gforthecontainmentexterior.Fromthepointofviewofthcanalysisofthestructuralre-sponsc,itdocsnotseemadequatetointroducethetorsionalinpu-thxoughtheuscof'accidental'ccentricities.Suchprocedurewhich)cadstothccouplingofthctorsionalandtranslationalrc-sponscinessentiallysymmetricstructuresdistortsthcrcsponscandthcnaturalfrcqucnciosofthcsystem.Thceffectsofthctcr-sionalinputmaybcsignificantfo-theturbinebuildingin.whichthcpossibilit'yofportionsofthestructureundergoinginelasticdcformationsmayincreasethceccentricity.Ifitisshownthatthcseismicexcitationatthcsitecor-I'cspondsmainlytohorizontallyincidentwaves,thcreductionsofthctranslationalandtorsionalresponseshouldbccvaluatcdonthcbasisofthcmorcexactmethodspresentlyavailablc.To~~
includeancxaggcratcdreductionofthctranslationalmotionwith-outincorporatingthcfulltorsionalcffcctsisimproper.Soil-StructureInteraction.InAppendixD-LL3AofRcf.1,thcapplicantpresentsacomparisonofthcresultsobtainedbythefixedbaseanalysisoftheaxisymmetriccontainmcntnodclwithtau-filtcredspectraasinput(F.B.Axisym.)withthoseobtainedfronasoil-structureinteractionfiniteclcmcntmodelwiththeNcwmarL;free-fieldmotion(withouttau-filtering)usedassurface'controlmotion(PLUSl<-SSI).BasedontheresultsshowninFig.3A-1ofAppendixD-LL3A,theapplicantconcludedthat'thcuseoftau-filteredinputswithfixedbasemodelsasusedforseismicanalys"sofDiabloCanyonstructuresisconservative.'hiscomparisonisnotvalid,andthec'onclusionisnotwarrantedbythcanalysis.Ioravalidcomparison,wemustrequirethatthefixedbaseaxis-ymmctricanalysisandthefixedbasePLUSllanalysisgiveesscntithcsameresponsecvcrywhcreexceptathighfrequencieswhcrcthcfixedbasePLUSllresultsnot.irfcludingthctau-filteringshouldbeslightlyhigher.ThisisnotthccaseasshowninFig.3ofthisrcportobtainedfromresultsshowninFigs.3A-1and38-5ofAppendicesD-LL3AandD-LL33.SincethcfixedbasePLUSllmod1is~inconsistentwiththcfixedbaseaxisymnctricmodel,novalidconclusionastothceffectsofsoil-structureinteractioncanbeobtainedbycomparisonsofthctypebcmentionedthatithasbccnshownshowninFig..3A-l.Itmustthattwo-dimensionalmodelssuchasPLUSllmayundcrcstimatcthcrcsponscatthctopofthcstructureby30to50pcrccnt.P-7
~4'InAppendixD-LL3B,comparisonsarcprescntcdoithcrcsponscforafixedbaseandanSSImodelbothcomputedusingPLUS)landVthcNcwmarkfree-fieldspectrum(withouttau-fi3.tcring)ascontrolmotiononthcfrcc-surface.Assuminpthatthcresultsprcscntcdarcinternallyconsistent,itispossibletodrawsometentativeconclusions.Fig.38-2ofAppendixD-LL38indicatesthat'hepca);accclcrations'nthecontainmcntcxtcriorobt'aincdincludingthcSSIeffectsareapproximately10pcrccntlowerthanthoseobtainedonarigidbase.SincethcSSIresult"automaticallyincludethecffcctsofscatteringofwavesbythefoundationaswellastheci'fcctsofradiationdampingintothcsoil,it'aybeconcludedthatthereductionof20percent(0.75gto0.6g)bytau-effctproposedbyNewmar)'ndasimilarreductionusedbyBlumcarcnotconservative.Figs.3B-3and38-4ofthesameAppendixindicatethatthcstoryshearforcesandoverturningmomentsonthecontain-mentexteriorobtainedincludingthcSSIareequalorslightlyhigherthanthoseobtainedfort)ierigidbasePLUS))model.Inthiscase,anyreductionofthcfixedbaseresultsbytau-filteringwouldunderestimatethcstressesinthcstructure.Assumingthat.hePLUS)iresultsarecorrectandconsistent,itmaybeconcludedthatthctaureductionproposedbyHcwmar)-andBlumcovcrcstimatcsthcreductioneffectsofwavescatteringandsoil-structureinteractioniorverticallyincidentshearwaves.Znparticular,.thcstrcsscscomputedonthcbasisofspectrarc-duccdbytau-filteringwouldu>>dcrcstimatcthcstrcsscsthatrc-suitiromthcSSIPLUS)lanalysisbyatleast20pcrccnt.~I
~~4~~'~~-~~4~~~.~Theapplicanthasindicatedthatthcshearwavevelocityatthesitecxcccds3600ft/scc.Thclow-strainanditcratcd'(orstraindcpcndcnt)shearWavesvelocitiesusedinthePLUSllSGImodelarenotrcportcd.Ircquostthatthisinformationbcmadeavailable.InAppendixDLL-15(Amendmcnt53),aunifor'm.shearMavevelocityof3500ft/sec.'isused.Irecommendthatthetau-filteringapproachbceliminatedandthatacompletethree-dimensionalsoil-structureanalysisforverticalandhorizontallyincidentSHwavesbcundertaken.ThisapproachMillhavotheadvantageofproducingrealisticestimatesof.theeavescatteringandtorsionalcffccts.ThepeakspectralresponseforthePLUSllfixedbaseanalysisoccursatafrequencyof5.3cpsi~hilcthecorrespondingfrequencyfortheaxisymmetricfixedbaseanalysisis4.5cps,indicatingadificrenceof18percent,.Ifthisdiffcrenccreilectsthoaccur-acywithWhichthcfixedbasefundamentalfrcqucncycanbccompu-Ited,thenitiiouldscornthatthepeakWideningofthefloorrc-sponscspectraof5percentonthchighfrcqucncysidemaybcin-@sufficient.ThePLUSllSSIresonantfrcqucncyis18pcrccntlo:~erthanthePLUSllfixedbasefrcqucncy.Thisagansccmstoindicaethatthe15percentpoa1vidcningoffloorresponsespectraonthclowfrcqucncysideisnotsufiicicnt.5.SeismicI:iskAnalscs.Scvcralseismicriskanalysesfor'thcDiabloCanyonsitehavebccnpcrformccl.ThccstimatcsobtainedfortheProbabilityofcxccdanccofthcllosgridesignspectrumdif-X'crbytwoordersofmagnitude.Thcapplicant(AppendixD-LL11)P-9
~~~~j~d~estimatesthattIicprobabilityofcxcccdingan'cficctivc'ccel-erationof0.75gin50yearsisO.lpcrccnt.AndersonandTrifuna.(Rcf.5)cstimatcthatthcprobabilityofcxcccdingthchigh-,frcqucncyportionofthcllosgridesignspectrumin50yearsvariesfrom10to20percent,dependingontheseismicitymodelconsidcre:Thcdifferencecorrespondingtoafactorof100to200canbcana-lyzedbyconsideringthcfollowingfactors:(i)Theapplicantconsidersthcprobabilityofcxccdanceofan'effective'ccelerationof0.25gwhileAnder-sonandTrifunacuseasabasisofrefcrenccthe0.75gHosgridesignspectrum.Theuscbythcap-plicantofan'effective'atherthan'instrumental'ccelerationof0.75greducesthcprobabilityofex-ccdanccbyafactoroffour.(ii)ThcuscofBlumc'sSAW-IV'andSA~il-Vattenuationre-(iii)lationsasopposedtothcuscoithcTrif'unac'src-lationsleadstoreductionofthcprobabilityofexccdancebyafactoroft'en.Thcrestofthcdiffcrcnccscorrespondingtoaiac-torof2.5-4canbeattributedtotbcdifierent'eismicitymodelsconsidcrcd.,llavxngisolatedthccausesofthcdiscrepanciesinriskesti-mation,Iicilldiscussthemindetail.Ihaveindicatedthatthc'reductionofthcpeakaccclcrationtoan'cffcctivc'cvclshouldnotbcusedinthcanalysisofnuclearpowerplants.Forthcpur-poseofestimatingthcriskofexceedingthcllosgridesignspectrum,P-10 ftheanchoraccclcrationof0.75ghouldbctreatedasactualpeak*acceleration.Inthiscase,thcprobabilityofcxccdanccin50yearsasobtainedbyBlume'sanalysiswouldbcofthcorderof0.4percent(refertoTable11.S,D-L).ll)ratherthanO.lpcrccnt.Thcmainsourceofdifferencesinseismicrisl'stimatescanbcassociatedwiththctypeofaccclcration-magnitude-distancerelationused.Thcapplicant'sriskanalysisisbasedonthcuscoitheBlume'sSAhf-IVandSAl)-Vprocedure.Inmyopinion,thisprocedureleadstoaccelerationswhichdonotreflectthestrongmotioninthenearsourceregionoflargemagnitudeearthqua)cs.ISoneconsiders.thethreelargestearthquakesforwhichrecordswercobtainedinthenearsourceregion,oncfindsthattheob-servedpeakaccelerationsarethreetotcntimeslargerthanthosepredictedbythcSAi~!IV-Vprocedure(Table2).SincethcstandarddeviationforpeakaccelerationscorrespondsapproximatelytoaSactoroftwo,itmaybeconcludedthattheSA'1procedureisnotvalidinthcnearsourceregion'oflargecarthqua);cs.Table2indicatesthatTrifunac'srelationsleadtoaccurateestimatesofthcobscrvcdpeakaccelerations(theaverageratioofobscrvcdtopredictedpeal:accelerationis1.07).Fig.41-IoiAppendixD-LL41showsthatthcuscoftheSA~Iprocedureleadstoprobabilitiesthatarc10timeslowerthanthoseobtainedonthcbasisofthcTrifunac's.relationsforthcsameseismicitymodel.Thc,scismi-toaprobilb11-ycalsoft)lcorderof4pcrccnt.citymodeldcscribcdinAppendixD-LLllleadsthenityofcxcccdingapeal;accelerationof0.75gin50
~g~~~~ThcseismicitymodelusedinAppendixD-LLlli"basedontheseismicrccurrcnccrelationobtainedbySmithforCentralCoastalCalifornia(AppendixD-LLllA).Theserccurrcnccrelationsarcbasedonthcseismicityduringthcperiod1930-1975anddonotin-eludethc7.2H1927carthquakcinthcregion.Therccurrcncc.curvesasshowninFig.11A-2ofAppendixD-LL11Aundcrcstimatcthcnumberofearthquakeswithmagnitudeslargerthansix,andarc~basedonanominalvalueforthcparameterbof0.92.AdditionalstudybySmith(AppendixD-LL45A)indicatesthatamoreappropri-atevalueforbwouldbeO.SS6.Theparameterbwhichcontrolstherelativecontributionofthchighmagnitudeearthquakestothetotaseismicityhasa'trongeffectonthecalculatedrisk.ThcuscofbO.SS6wouldincreasethecalculatedprobabilitiesbyafactoroftwo(r'cfcrtoTable45.3ofAppendixD-LL45).ThcseismicitymodelconsideredinAppendixD-LL11isconsis-tentwiththcseismicityobtainedinAppendixD-LL41usi'ngthegeologicrecordoffaultdisloca'tion(a=3.12inD-LLll,a=2.SObasedon10yearsrecordanda=3.20basedon20x10years6recordinD-LL41).Theseismicitycalculatedonthcbasisofthegeologicrecordoflateralfaultslipdocsnotincludetheseismi-cityassociated>>'ithvorticalslipalongthcHosgrifault.Hamiltor(AppendixD-LL41A)quotesarcportbyEarthScicnccAssociatesin-dicatingthatthc.'lateralslipwasprobablysubordinatetovcrtica)movcmcnt.'fthisisthccase,thcseismicityshouldbcincrcascdtoaccountiorverticalslip.Consideringallthciactorsmcntioncd,itsccmsthatthcP-12
~~probabilityof10to20pcrccntin50yearsobtainedbyAndersonandTrifunacproperlyreflcctsthcseismicrisl'fcxccdanccofthcllosgridesignspectrum.
fv~~~~H.~t-vREFERENCESSeismicEvaluationforPostulated7.ShfllosgriEarthquakc,Units1and2,DiabloCanyonSite,PacificGasandElectricCompany.*02.Trifunac,hf.D.,"Preliminary,AnalysisoithePeaksofStrongEarthquakehfotion-l)cpcndcnceofPeaksonEarthquakehfag>>i-tudc,EpicentralDistanceandRecordingSiteConditions,"Bull.Scism.Soc.ofAner.,Vol.66,pp.189-219{1975).Page,R.A.,D.hf.Boore,ff.B.Joyncr,andH.fV.Coulter,GroundhfotionValuesforUseintheSeismicDesignofthcTrans-AlaskaPipelineSystem,U.S.GeologicalSurveyCircular672,1972.4.Trifunac,hf.D.,"ForecastingthSpectra'1AmplitudesofStrongEarthquakeGroundhfotion,"Sixthli'orldConferenceonEarth-quakeHnginccring,NcvDelhi,India,1977.5.Ncwmark,N.hf.,"TorsioninSymmetricalBuildings,"Fourth'forld"onfcrence.onEarthquakeEnginccring,Vol.II,A-5,Santiago,Chile,1969.6.Anderson,J.G.,andhl.D.Triiunac,UniformRiskAbsoluteAcccler4ionSpectrafortheDiabloCanyonSite,CaliforniARcporttothcAdvisoryCommitteeonReactorSafcguards,U.S.NuclearRegulatoryConmission,Dcccnbcr,1976.'~~
llp~i~ii~,Ig~ThlSLEl.COMPARISONOX'AXIMUMGROUNDMOTIONSPeakvaluesusedby1Ncivmar.k0.75M=6.5Trifunac0.69(1.29)USCSNo.6720.9QM=7.5Trifu>>acUc,No1,07(2.00)v(in/scc)max23(48)3939(84)(in)8(19)1612(30)~~4'cxvmark,N.M.,"ARationaleforDcrelopn>cntofDesignSpectraforDiab'.oCanyonReactorFacili(y,"AppendixC,SupplcrncntNo.5,SER,Diablo~CanyonNuclearPov:erSta(ionUnits1and2,NRC,1976.Average(average'+standarddeviation)peakmotionforrockatancpiccntraldistanceR=7.5kmbscdonl'rifunac,M.D.,"PreliminaryAnalysisof(hcPeaksofS(ro>>gIart!iquakcGroundMotion-DcpcndcnccofPeaks.onEar(I]quakeMagnitude,EpicentralDistanceandl<ccordi>>gSi(cCondi-tions,"B.S.S.A.,66,149-219(1975).~Page,R,A.,ctai.,"GroundMotionValuesforUseinthcSeismicDcign~ofthcTrans-AlaskaPipelineSystem,"GeologicalSurveyCircular67?,1972,~~~~~~P-15 TABLE2.'ComarisonofRecordedandPredictedPeakAccelerationsRecordedPeakAccel.SAWry-SA,4V(4)PredictedRatioPeakObserved/Accel.PredictedTrifunac()PredictedRatioPeakObserved/Accel.Predicted1971Pacoima()1967Koyna...i()1.25g0.63g0.80g0.12480.213g0.190g10.082.96-4.210.839g0.766g0.900g1.490.820.89.5.751.07(1)hf=6.5,epicentraldistance3km,focaldepth15km.(2)h!6.5,epicentraldistance5km,focaldepth5km(assumed).(3)hl=7.2,epicentraldistance10km,focaldepth25.km..(4)~Ys12,000,62.04,y0(5)s2sp0.50' joosvVtlC7v~oV~So~A0ao5'~pdSl(EOdo'brOC~t~dO~pt4>rO~r<JIyIqlpoItlopoo.opO.oso.fo.,fFrequency,cps5lo~"0'Oioo~~~~8~~~F[Q.1-DESTGi45P"CTRUMCOMPARED71HHPACOMADAiVi.SP"CTRA,2PERCENTDAi&PPiiG,~~g
~~3.02.5n~1.5~~e~0~~Dcgigll,5$CCft'll~Ifc0)(8LmsiicP,/%5).0.50.2.0,3o.97(sec.)a,"I,~~~~fQ:I-f~0~rrr..2-r.oacrAnr.".owot'v:::r.7t:At,Gttt:vt.s.
~r~~~~~A'0/DAC.POIlVIi%OPOFCCNIQ/NiHc:F7/lQQ/if+/~Q~~~r~85r0goJS40V0fo0~(8I~~I~,~)~~I)I~~~~~er~~)~~~~I~eI~=-I0lI~~~~IJii.I~i~~~IIt~rrIo~~Itft.fj!l~~j)I/I~~IrlfII~~~)Ia~twe}ilM~.PLUSH4~I~.i~I~I~~Il1~.'4~:~~\roreI)I,ssg'7"LUsH0.3(.o2.050lO/o0 1
~~~Q~~~~~,)'TTlENT,()COetOV'rsONSrISWICOLSIGMLEVELSFOl(DIABLOCAliYOihSITI!INCALII'OR'(IAby'.D.Vrit'uoacApril,1973~~~
I~.3~~Thcfollowingconvncntsdealwithseismicdesigncriteriaforthc\DiabloCanyonsiteinCalifor>>iaandrcprcsc>>tabriefsunnnaryofmyobservationsa>>dprclitoi>>aryco>>clusio>>swhicha:cbasedo>>misccllancouswrittenmaterialandona>>unbcrofmeetingsduringtheperiodstarti>>ginthcsummerof1977andendi>>ginAprilof197S.Infoxtnatio>>whichIhadoncertainaspectsofthiseffortmaybcincomplete."Thegeneralpictureandthesummariesofthccurrentstatusofthisprojectncvcrthclcssseem.adequateforthcfollowi>>gcorrzc>>tsandrccomrtcndations.HuchhasbeenwrittenaboutdctailcdaspectsofseismicdesigncriteriaforthcDiabloCanyonsiteanditwouldb"impracticaltoaddressagainnun>crouspointsindetailandcompletely.Rather,IwillattempttopresentanoverallsunnnaryofwhatIbelicvctobeunresolvedproblemsatpresent,andwhatmightbcpossibleavcnucstoresolvethem.GeneralCommentsonthcCurrentIn)utsandCriteriaforSeismicDesinGc>>crallyaccepted<<ss(nnptionappearstobcthatthcSSEonHosgrifaultoppositethcplantsiteshouldbcanhi=7.5carth-quake.Thistnag>>itudc,rcconnnc>>dcdbyUSGS,hasbccndctcrmincdmainlyo>>thebasisofthcpossiblelc>>gthoffaultingo>>thcllosgrifaultsystem.2.Sincehl=7.5ata(lista>>ccof5-10kmfromthcsiteleadstolargepeakaccc3cratio>>(aboutlg)considerableefforthasbcc>>dcvot'c(lt.othca>>alyscsldll)charedesig>>('.(ltoshowthatQ-2
~~~~theselargeamplitudescana>>tlmaybcrcduccdthroug)tconsidcra-tionoft)tcfol)owingphc>>omcna:a)Scatt:eringanddiffractionofhig)tircqucncywavesfromthcfoundationsoEdifferentplantstructures.hasbcc>>proposedasavchiclctojustifyreductio>>ofhighfrcquc>>cyspectralamplitudes(Tcffcct).Thcmannerinwhicltt:his.reducti.onhasbccnaffcctcdrcquircsunrcalisti.cassumpt:io>>s,forex-ample,thatfoundationisrigid.Themannerinwhicht)tisassumptionisintroducedintoanal>sisifoftenon-sidedandconsidersmainlyonlyt)ioseconsequencesoft:hcphysicalphe>>omenaw)tie)tleadtoreduction.ofspectralamplitudes.Othcxco>>sequencesofthisphenomcno>>,forexample,torsionalandrockingcxcitatio>>soffoundatio>>>>whic)tmayamplifythcostructuralresponsehavebeen,sofar,eitheroverlookedortreatedinadcquatcly.T)tishasbeenachievedb>utilizationofdynamicmodelsfor'nalysiswhicharesodeiincdthatonlyanincomplctcph>sicsoftheproblem,i.e.,seismicexcita-tionandt)tcstructuralresponse,canbc.considered.b)Thcterm"effectivepeakaccclcration"hasbccnintroducedsuggcsti>>gtltatthcstructurewill"sce"somcthi>>gsmallert)tanactualpeakaccclcration.Thoug)tsuc)tapproachmaybcuscL'ulforcart,ltquakcrcsistcntdesignofordinarystructuresbymeansoit)icrcsponscspectrumtcclutiquc,thcterm"cffcc-tivepeakaccelcratio>>"ltasnotbccndcfincdi>>awaythat:would)c>>ablet)icderivationofco>>sistc>>tresultsbyscvcral~~~~Q-3 diffcrcntcxpcrtsinthcfield.Si>>ccthcproccdurcsforscalingRegulatoryGuide]..60spectraarcbasedonmaximumvibratorygroundacceleration"(asdcfincdinAppendixA)thisdeparturefromroutinedesignpracticesmakesitdiffi-culttocvaluatcthcnumberandthcnatureofthcconscqucnccswhichwouldresultfromsuchanapproach.c)Hypoccntralratherthandistanceclosesttothefaulthasbeepusedtocvaluatcpeakandeffectivepeakacceleration.Thisassumptionimpliescertainanglesofapproachofseismicwaveenergy.Theseangleso'fapproachshouldthenbecon-sistentwiththcextenttowhich"reffect"isallowedtoinfluencethespectralamplitudes.Littleornoattentionseemstohavebeengiventomutualconsistencyoftheseassumptionsandinsome.cases,inconsistentassumptionshavebeenutilized.Forcxamplc,deephypoccntcrwouldincreasethedistanceatwhichpeakaccelerationisevaluated,thus*reducingthcestimateofpeakaccclcrat'onamplitudes.Thiswould,however,alamoimplythatthewavesarrivetowardsthcfoundationalmostvertically.Inconsiderationof"Teffect"howcvcr,horizontaldimensionsoffoundationsappeartohavebccnusedimplyinghorizontalincidcnccofwaves.d)Thclargedampingequalto7'ohasbccnadoptedfordynamicrcsponsccalculations.Thoughthcapparentdampingforthccomp)ctcsoil-structuresystem,subjcctcdtocarthquakcexcitationma>bcmuchlargertluin7"',inadcquatcbasishasbeenpresentedtnjustify7.;danglinginstructuralsystems~~,Q-4"~'l~
'4lonly.Sclcctio>>oftoolargestructuraldampingcoupledwithonlytwo-dime>>siona1orsimplethrcc-dimcnsio>>alanalysisofsoil-structureinteractioncanleadtou>>rcliablcrcspo>>scestimates.3.Atleastthrccseismicriskstudieshavebccnprcparcdtocstimatcthcprobabilityofcxcccdingthesclccteddcsig>>criteriaatthcDiabloCanyonsite(Blumc,Anga>>dNc>>mark,A>>dcrso>>andTrifunac).Thesestudieshaveproducedresultswhich,insomecases,differbyasmuchastwoordersofmagnitude.Concurrent>>iththecom-parisonsofthcscstudies,.considcrablccfiorthasbccndevoted.todiifcrcntdetailsinthemethodologyemplo>edinthesecalcula-tions.Littleornoexpliciteffortanddiscussionhasbccnde-votedtothemodelsofseismicitywhichareessentialinputintosuchcalculations,evc>>thoughthismayrcprese>>tthcmostimpor-ta>>tcontributiontothcdiscrepanciesamongthcresultsofdiffcrcntstudies.I>>someextrcmecases(c.g.,reportbyBlumcand)'iremidjian)claboratcworkhasbcc>>carriedout,apparentlyinvain,toshowthataparticularmethodforscalingpeakacccl-cration(Trifu>>ac,)976)supposedlyleadsto"toolarge"estimatesofpeakacccleratio>>irrcgardlcssoithcfactthatthoseresultsofTrifu>>ac(1976)have>>everbeenusedanddonotrcprcscntabasisforthedcrivatio>>ofseismicriskmodelsbyAndcrso>>.a>>dTrifunac.InthcrcportbyA>>ga>>dNcwmark,substa>>tiallysmallertha>>averageseismicityhasbcc>>assumed>>car,thcsite.Thismayleadtoa>>u>>dcrcstimatcofLctualrisk.~~~~~Q-5I C~ERecommendationsA.Groundhfotion.'.DctcrministicapproachbasedonthcassumptionthatanearthquakeoCmagnitude)f=7.5orgreater>>i]1occuroppo-sitethcplantsiteshouldbcre-cvaluatcd.Thismagnitudemightbeanindicatorofthccxtcntofgeologicfaultingphenomenabutitisnotnecessarilythcmostrcliab)ebasisforevaluatingthenatureofstrongshakingclosetothefault.Therearcnumerousexamplesinliteratureofsig-nificantdifferencesbetween)I<and))S,forexample,>hicharcbasedonshortandlongperiodseismic>>aves,respectively.Oftenstudieshaveshownthatlargerearthquakesmaybcthoughtofasasequenceofseveralormanydiscreteevents>>hichcansequentiallytal'eplacealongalongfault.Finally,I'helargestrecordedacceleration,sof"r,hasresultedforh)<6.5only.Forthcscreasons,andfromthcdesignvic>>-point,I>>'ouldprcfcrtoadopt)I=6.5onHosgrioppositethcsiteandnothi=7.5.2.Near-fieldsourcetheory(notafiniteelementorfinitediffcrcnccmodelofthcsourceanditssurroundings)couldbeusedinconjunctionwiththespectralanalysisofstrongPmotionsrecordedcl..cwhcretocvaluatctheamplitudesofresponsespectraindcpcndcntoC.peakaccc)crationestimatesorofseismicrisk<<nalyscs.
G.~lies>on.".c:h1.Three-dimcnsio>>alsoil-structureinteractionanalysisshouldbccarriedout.'I'hissi>ouldbedoneassumi>>gthatthcfrcc-fieldresponsespectrafordesignresultfromi>>cidcntSII,SVorltaylcighwaves.ForSl}andSVexcitation,horizontal,verticaland45incidcncca>>alysisshouldbcconsidcrcd.Thisapproacl>wouldofferthcfollowi>>gadvantages:a.The"veffect"ifprcscntwillbcaccou>>tcdforcorrectly.b.Torsionala>>drockingcxcitationswillbeincludedi>>totheanalysi.scorrectly.c.TheproximityofthecartIiquakcsourceandthcfactthat~thewavesmostlikelyarrivehori"o>>tallywillbcaccountedforcorrectly.d.Thcradiationdampingi>>thcsoilwillbeintroducedintoanalysisproperlysothatthchighvalueof7'orstruc-turcswouldnotbcrcquircd.L'xccptforthcfactthat7'odam}ii>>gispcrmissi}aleaccordi>>gtothercgulati>>}',}',uidc].61,thi>>highstrucfur>>ldarn})i>>grccollllllcndedforthcseismic>>>>>>lysisattl)cDial)loCa>>yo>>.sitehas>>otI)ccnjustif-iedd.Forcedvihr>>lio>>test(avai1>>l>lci>>t}.S.a>>il.1>>p>>n)data,whereflicetlect.ofsui}-structurei>>ter>>etio>><<>>diliIfere>>tmodeofcncr},)i>>I~>>ti>>totl>estructurepluri>>},n>>ex/crime>>t,relativetoi>>eide>>t.<<:>>tl<>>>k~w>>vv."is>>ot>>econ>>tedI'ur,maybcoflitt]cus()>>rs'}al>I1,'sl1L>>}',.LI'l.>>e(l}>>ILI>>mI)I>>}}>>~(rueturusa>>lltht1jcompo>>e>>},sIorsclsmte'I'csI)0>>!4cc>>Icul>>C10>>s.Q-7 I,pC'yI' ATTACHHENTR"IF.~BgUNITEDSTATES~DEPARTl)ENTOFTHEINTERIORGEOLOGICALSuRVEV-ESTIYiATIONOFGROUNDi~OTIONPARAMETERSDavidH.Boore,AdolphA.OliverIII,RobertA.Page,andWilliamB.QoynerOPEN-FILE)REPORT78-509PreparedonbehalfoftheNuclearRegulatoryCormissionThisreportispreliminaryandhasnotbeen.editedorreviewedforconrormity~vithGeologicalSurveystandards.yggoGlCALgg~,~~ggi.opARicJUi'l2197SLl0RAG"
~\m'I~2fh~'4I'~I.v'I<hqoake.ThesolidMnesshowthe70percentpredonintervalforthe'aqua>>tude7.1-7.?datasetofthisreport.thostofthepointsinthatdataet~~-.g9>>u~',>camefromthemagnitude7.7KernCountyearthquake.TheamountofdisagreementshowninFigures47and48isnotsurprising~jviewofthedifferentassumptions,differentmeasuresofdistance,and"vs~~~~'djfferentdatasetsusedinarrivingatthedifferentcurves.The1djsagreementis,asmightbeexpected,thegreatestatshortdistances.ESTIMATIONOFPENPARAMETERSAT'HORTDISTANCES6eneralcomments.Theregressionlinesgiveninaprevioussectionofthis\reportprovidethemeansforestimatingpeakgroundmotion'parametersatdistancesgreaterthan5kmf'rmagnitude5.0-5.9earthquakes,atdistancesj.greaterthan15kmformagnitude6.0-6.9earthquakesandatdistancesgreatervthan40kmformagnitude7.0-7.9earthquakes.Unfortunately,mostoftheFdaniagefromearthquakescanbeexpectedtooccuratshorterdistances..Attemptshavebeenmade,asdescribedintheprecedingsection,toprovide%11yC.r.'~'-rmcurvesforestimatingatshorterdistances.ForreasonsgiveninthePrecedingsectionwedonothavecompleteconfidenceinthosecurves.Mewillnotventureourownsetofcurves,butwilldiscussbrieflysomeoftheconsiderationsbearingongroundmotionestimatesnearthesource.FurtherdiscussionofthesequestionsingreaterdepthisgivenbyBoore(1974).Therehavebeenanumberofstudiesusingsimplifiedmodelsofthefault;ingprocesstosetlimitsonthegroundmotionatthefaultsurface(Housner,1965;Ambraseys,1969;Brune,1970;Ida,1973).Brune's(1970)nearsourcemodelassumesthatruptureoccursinstantaneouslyoverthefault
'IIpeatparticieve1otyisproportionaltothestsdropandn')pile.aquas>00cm/secforastressdropof100bars.Thepeakaccelerationisinfiniteqfallfrequenciesareincluded,butiffrequenciesabove10Hzares~filteredoutoftheaccelerationpulsethepeakvalueis2g.Thisisausefulmodelforrelatinggroundmotiontothephysicsoftheruptureprocess,'utitdoesnotgivefirmupperlimits.Anargumentcanbemadeforlarger~tionsifonetakesrupturepropagationintoaccount(Ida,1973;Andrews,1976)..Furthermore,thepeakvaluesofgroundmotionmayrepresentlocalizedhihstressdropsasHanksandJohnson(1976)havesuggestedforpeak19acceleration.Suchlocalizedstressdropsmighteasilyexceedonekilobar...:":-..',ThepeakaccelerationatthesurfaceislimitedbythestrenothofnearsurfacematerialsashasbeenpointedoutbyAmbrasey(1974).Forsitesnearthesourceunderlainbysoilmaterialoflowstrength,thisfactormaycontrolthevalueofpeakacceleration.Thisconsiderationmayalsoapplytorock'~~sitesiftherockissufficientlyweathered.Determinationoftholimitingacceleration,however,wouldrequirereliablemeasurementofthedynamic,inh~k.situstrengthofthesoilataparticula'rsite.Intheabsenceofadequatemeasurementsonemustpresumethattheaccelerationcouldbeatleastaslargeas0.5g,whichwasrecordedonathicknessofmorethan60metersof'ater-saturatedalluviumatstationnumber2intheParkfieldearthquake\(ShannonandWilson,Inc.andAgbabianAssociates,1976).~~Inthecaseofpeakdisplacement,aspointedoutbyTrifunac(1976),ifeI,oneassumesnoovershoot,thepeakislimitedtolessthanonehalfthestatic>slocationamplitude.Thelatterisknownformanyhistoricalearthquakes>>dmaybeestimatedasafunctionofmagnitude(BonillaandBuchanan,1970).TheaccelerogramrecordedatPacoimaDamduringtheSanFernandoR-3
\<earthquakehasmajorsign%>cancefornearsourcegroundWotionestimates.Theinstrumentislocatedonly3kmfromtherupturesurfaceatarocksite~~erethetopographicreliefissevere.ThepeakrecordedhorizontalIaccelerationis1.25g,velocity113cm/sec,anddisplacement38cm.Thisis1~mtpeonlyaccelerogrameverrecordedwithin5kmforanearthquakeofmagnitudeaslargeas6.4,andassuchoughttohavestronginfluenceonestimatesofnear-sourcegroundmotion.Thepossibilityoftopographicamplificaionneeds,consideration.Atwo-dimensionalfinite-differencestudyby'Boore(1973)suggeststhattheaccelerationmayhavebeenamplifiedbyasmuchas50Percentbutthatth'evelocityanddisplacementwererelativelyunaffected.Giventheseconsiderations,itwouldbedifficultforustoacceptestimateslessthanabout0.8g,1'IOcm/sec,and40cm,respectively,forthemeanvaluesofpeakceleration,veloc'td'~em~ttrocksiteswithin5kmoffaultruptureinamagnitude6.5earthquake.Merecognizethatthesenumbers~iepresentoneearthquakewithaparticularfocalmechanismandthatestimatesareboundtochangewhenmoredatabecomesavailable.>lepresumethatthe~P.~ss.statisticalscatteraboutthemeanwillbeatleastasgreatforthenear-insitesasatthegreaterdistanceswheredataisavailable.TheaccelerographatPacoimadamwasonly3kmfromthenearestpointonmt'herupturesurface,butthenearestpointwasnotthesourceofthepeak>>tions.AsnotedpreviouslythesourceforthepeakvelocityandforthePeakaccelerationaredifferentpointsontherupturesurfaceseparatedbyPerhapsasmuchas20km(Hanks,1974;BouchonandAki,,1977).~.Abovemagnitude6.5thereareessentiallynodataforestimatingtheeffectofmagnitudeonnear-faultpeakacceleration,velocityand4isplacement,otherthanthestaticfaultoffsetdividedby2asaboundon II~\~~~..~hg/,thepeakd~spaoement.Conservatismrequiresthepresumptionorsome[noreasewrathmagnitude-HanksandJohnson{1976)presentedasetofpeakaccelert'ataat.sourcedistanceofapproximately10kmforearthquakesinthemagnituderange3.2-7.1.Theonlydatapointabovemagnitude65wasforthimperialValleyearthquakeof1940whichtheyassignamagnitudeof7.1incontrasttoourvalue6.4,sothedatasetcanbeappliedtomagnitudesgreaterthan6.5onlyasanextrapolation.Thedatasetshowssomedependenceofpeakaccelerationsonmagnitude,butHanksandJohnsonarguethatthedataareconsistentwiththeideaofmagnitude-independentsourceproperties.Thedataplottedasthelogarithmofpeakaccelerationagainstmagnitudecanbefitbyastraightlinewithaslopeequivalenttoanincreasebyafactorof1.4permagnitudeunit.Thisshouldnotbeusedforextrapolationbeyondccgnitude6.5,however,becausethedatasetwasdeliberatelychosentorepresentrelativelyhighvalues,andthustheslopeofthelinefittingthedatamaynotbethesarneastheslopeofthelinerepresentingmeanvaluesor,for.thatmattero,ofthe11nerepresentingvaluesforanyfixedprobablity.'.-.':-Atsitesotherthanrocksitesaccelerationsmightbelessbecauseofthelimitedstrentghofnear-surfacematerials,but,aspreviouslynoted,determininhogwmuchlesswouldrequ>redynamic,in-situmeasurementsofsoilproperties.Theamplif~cationofpeakvelocityatsoilsitescomparedtk~'sites:maynotbesogreatclosetothefaultbecauseoftheenergylostinnonlinearsoildeform*eformatlon,butnumb:.icalmodeling(JoynerandChen,1975)demonstratesthepossibilityofamplificationofvelocitybyasmuchas30<<entevenundercond)talonsofintensedeformation.Thepossibilityofgreateramlificatpioncannotbeexcluded.Anplificationofdisplacementato<1sitesshouldbeexpectedclosetothefault,-asatgreaterdistances,if
.~thesoilcolumnissufficientlythick.ACKNOWLEDGMENTSWearegratefultoR.P.Maleyforassistanceinobtaininginformation0nstrongmotionrecordingsiteconditionsandtoA.G.Bradyforunpublished'trongmotiondata.R.B.Natthieson,T.C.Hanks,andA.G.Bradyreviewedthemanuscriptandsuggestedimprovements.lI~"\~1('1)~'h'~~I~g\~~PC~\1'I+~;'.ZI'~~R-6}}
