简介：Amethodofestimationofoccurrenceprobabilityofearthquakeintensityatagivensitefromtheresultsofaten-yearscaleofearthquakepredictiondescribedwithaprobabilityofoccurrenceinagiven"predictioncell"isproposedinthispaper.2316citiesandtownsinChinawereanalyzedbyusingthismethod.TheprobabilityofintensityⅥ-Ⅸweregivenforeverycity.Theseresultscanbeusedfortheearthquakeinsurance,lossestimation,andplanningofdisasterprotection.

简介：Accordingtotheresultsofsiteseismichazardanalysisaccomplishedinthepastdecades,96site-relateddesignspectraareselectedassamplesinthisstudy.Theresultshowsthatthevalueofthecornerperiod(Tg)ofthedesignspectruminGBJ11-89(ChinaSeismicBuildingCode,issuedin1989)islowerthanthevalueobtainedbysiteseismichazardanalysis.ThesamesituationexistswhenwecomparethedesignspectraoftheCodestothespectraaccordingtotheearthquakerecords.Thevalueincurrentseismicdesigncode,GBJ50011-2001issuedin2001,isgreaterthanthatinGBJ11-89,butstilllessthanthevalueobtainedbysiteseismichazardanalysis.Ifweacceptthevaluegotbysiteseismichazardanalysis,wehaveasuspicionthat2/3ofbuildingsbuiltaccordingtoGBJ11-89willnotbesafewhenanearthquakewith2%probabilityofexceedancein50yearsoccurs.

简介：Morethanahalfofstrongearthquakesintheworldarelocatedinshallowdepthatthesubductingplateboundaryinsqueezedzones.Owingtothedifferenceinspeedbetweenthemovingseaplates,thestrainenergyisaccumulatedandreleasedcyclicallyinsqueezedzones.Severalmethodsweredevelopedtoanalyzethemedium-andshort-termpotentialofmainshocks.Thesemethodscanbeclassifiedinto(1)lessdatasystemsusingthetheoryofgreymodelforearthquakeprediction,(2)quasi-periodicsystemsusingearthquakeactivityanalysis,(3)systemsofgroupedactivityusingorderanalysis,and(4)nonlinearsystemsusingbackpropagation(BP)ofneuralnetworkforpredictionanalysis.Basedupontheseanalyticmethods,riskmapsforthepredictionofstrongearthquakescanbedrawnusingtherecordsofstrongearthquakesinTaiwanforthepast100years.Theseriskmapsinclude(1)aseismicriskmap,(2)alossriskmap,(3)ahazarddegreemap,and(4)alossdegreemap.Theseriskmapsmakeitpossibletodoamedium-termpredictionofmainshocksonthe10-yearscale.

简介：ＫｉｎｅｍａｔｉｃｆｅａｔｕｒｅｓｏｆｔｈｅｓｅｉｓｍｏｇｅｎｉｃｆａｕｌｔｏｆｔｈｅＴａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅａｎｄｔｈｅｒｅｃｕｒｒｅｎｃｅｐｅｒｉｏｄｏｆｌａｒｇｅｅａｒｔｈｑｕａｋｅｓＪＩＥＬＩＵ１）（刘洁）ＨＵＩ－ＺＨＥＮＳＯＮ...

简介：Characteristicperiodisanimportantparameteroftheseismicdesignresponsespectrum.Thereisimportanttheoreticalsignificanceandengineeringapplicationvaluetothestudyofthecharacteristicperiodofseismicdesignresponsespectrumofultrahighvoltage(UHV)electricalequipment.Inthispaper,1448horizontalearthquakerecordswithintheworldscopeincludingtheUnitedStatesandJapanforSiteClassⅢwereanalyzed.Resultsshowthatbothmagnitudeandepicentraldistancehavegreatinfluenceonthecharacteristicperiod.About80%ofcharacteristicperiodsofstrongearthquakerecordsareabout0.9s.Statisticalanalysiswasconductedontheseismichazardassessmentresultsof312projectsofChinainrecentyears,anditisfoundthatabout70%ofcharacteristicperiodsareabout0.9s.Combinedwiththerelatedcodecomparisonandanalysis,itissuggestedthatthecharacteristicperiodoftheseismicdesignresponsespectrumofUHVelectricalequipmentshouldselect0.9sinordertoeffectivelyguaranteetheseismicsafetyofUHVelectricalequipment.

简介：Byanalyzinghigh-resolutionSPOTimagesandincombinationwithfieldworkandchronometry,threetypicalfault-offsetsitesonthesouth-middleAltynTaghstrike-slipfaultwerestudiedtoobtainthesinistralhorizontalsliprateofthefault.AtAnnanba,theleft-lateralstrike-sliprateonabranchofthesouthAltynTaghfaultis7.5±1.7mm/asince9.36±0.73kaBP.AtSevenSpring,thefaulthasfourbranchesandtheleft-lateralstrike-sliprateononeofthemis2.3±0.5mm/asince13.86±1.07kaBP,anditisdeducedthatthetotalsliprateofallthefourbranchesis6.9±1.5～9.2±2.0mm/asinceHolocene.AtYuemakeqi,theleft-lateralstrike-sliprateofthefaultis10.6±3.0mm/asince4.73±0.38kaBP.Aslip-rateof7～11mm/aonthemiddlesegmentoftheAltynTaghfault(between88°30'Eand93°05'E)sinceHolocenecanbededucedfromthethreesitesmentionedaboveandtheresultissimilartothelatestGPSobservation.

简介：Ｉｎｆｌｕｅｎｃｅｏｆｌｏｎｇｐｅｒｉｏｄｓｅｉｓｍｉｃｗａｖｅｓｉｎ┐ｄｕｃｅｄｂｙｔｈｅＴａｉｗａｎｌａｒｇｅｅａｒｔｈｑｕａｋｅｏｎＳｈａｎｇｈａｉａｒｅａＫＵＮ－ＹＵＡＮＺＨＵＡＮＧ（庄昆元）ＹＯＮＧ－ＬＩＮＸＵ（徐永林）ＪＩＡＮ－ＷＥＮＳ...

简介：TemporalchangesinsiteeffectsareobtainedusingtheHVSR(horizontal-to-verticalspectralratio)methodandstrongmotionrecordsaftertheMw7.6Chi-Chiearthquake,Taiwan.Seismicdatarecordedbetween1995and2010areused,comprising3,708datafrom15stationsadjacenttotheChelungpufault.Temporalfluctuationsaredeterminedbyanalyzingthesiteeffectvariationusingatime–frequencyvariation(TFV)diagrambasedontheseseismicdata.Stationsadjacenttothefaultshowsignificantdisturbancesintheresonancefrequencyat16–26Hz.StationTCU129showsa40%dropinfundamentalfrequencyafterthemainshock,andagradualreturntotheoriginalstateovernineyears.Forstationslocatedfartherfromthefaultzone,suddenchangesintectonicstressplayadominantroleintemporalchangestotheHVSR.Animpactanalysisofthedirectionalfactorconfirmsourfindingthattheproximityofthefaulttoseismicstationshasthemostinfluenceondata.

简介：Alargeearthquake(MW=7.6)occurredinJiji(Chi-Chi),Taiwan,ChinaonSeptember20,1999,andwasfollowedbymanymoderate-sizeshocksinthefollowingdays.TwoofthelargestaftershockswiththemagnitudesofMW=6.1andMW=6.2,respectively,wereusedasempiricalGreen(sfunctions(EGFs)toobtainthesourcetimefunctions(STFs)ofthemainshockfromlong-periodwaveformdataoftheGlobalDigitalSeismographNetwork(GDSN)includingIRIS,GEOSCOPEandCDSN.FortheMW=6.1aftershockofSeptember22,therewere97pairsofphasesclearenoughfrom78recordingsof26stations;fortheMW=6.2aftershockofSeptember25,therewere81pairsofphasesclearenoughfrom72recordingsof24stations.Foreachstation,2typesofSTFswereretrieved,whicharecalledP-STFandS-STFduetobeingfromPandSphases,respectively.Totally,178STFindividualswereobtainedforsource-processanalysisofthemainshock.Itwasnoticedthat,ingeneral,STFsfrommostofthestationshadsimilaritiesexceptthatthoseinspecialazimuthslookeddifferentoroddduetothemechanismdifferencebetweenthemainshockandtheaftershocks;andindetail,theshapesoftheSTFsvariedwithazimuth.BothofthemreflectedthestabilityandreliabilityoftheretrievedSTFs.ThecomprehensiveanalysisofthoseSTFssuggestedthatthiseventconsistedoftwosub-events,thetotaldurationtimewasabout26s,andontheaverage,thesecondeventwasabout7slaterthanthefirstone,andthemoment-rateamplitudeofthefirsteventwasabout15%largerthanthatofthesecondone.

简介：Basedonwaveformdata,severalmethodstodeterminefocalmechanismsofsmallearthquakesweredevelopedsince1980.Kisslinger(1980)andJulian,Foulger(1996)proposedanapproachtodeterminesolutionbyusingamplituderatioofPandSwave.Schwartz(1995)devisedamethodtodeterminesolutionsbytheuseofpolaritydataandamplitudesofseismogramenvelopes.Amplitudesofshortperiodseismicwavespropagatinginaninhomogene-ousmediumaresensitivetothevariationinvelocityandQstructure.Nakamura,etal(1999)tookmediuminhomo-geneityintoaccountindeterminingfocalmechanismsofsmallearthquakesusingwaveformdata.Ifthelocationsofsmallearthquakesareconcentratedinasmallregion,wecanassumethattheraypathsfromtheeventstoagivenstationarealmostthesame.SoPandSwaveattenuationsareindependentofeventlocations.Inthiscaseitiscon-venienttodeterminefocalmechanismsoftheseeventsbyusingshortperiodPandSwavedataj.Focalmechanismsolutionsofsmallearthquakesin5regions,i.e.,Rongchang,Mabian-Muchuan,Ya￠an,BaoxingandMianzhu,whicharecoveredbytheChengduTelemeteredNetwork,areobtainedbyanalyzingthePpolarityandshortbodywaveamplitudedatarecordedinthenetworksince1992.AccordingtothemethodproposedbyGephartandForsyth(1984),basedonwelldeterminedfocalmechanismsolutionsin15sub-zonesofSichuanandYunnanarea,threeprincipalstresstensorss1,s2,ands3,insteadofaveragesofP,B,andTaxisofthesolutions,aredeterminedtorepresenttheregionalstressfielddistribution.