简介：EasternChinaandvicinalseaareas(98°~150°E,5°~50°N)arelocatedinthejunctionzoneofEurasianandPacificplates,anditisalsoprofoundlyinfluencedbythecollisionbetweenIndianandEurasianplates.Weutilizedsurfacewavedatarecordedby35digitalseismicstationsinthearea,extracteddispersioncurvesoffundamental-modeRayleighwavesalong1252pathsbymeansoftime-frequencyanalysisbasedonmultiple-filterandothertech-niques.Thestudyareawasdividedintoagridof1°′1°,groupvelocitydistributionsoffundamentalRayleighwavesbetween10~158sweredeterminedbyOccam￠sinversion.Thesevelocitydistributionsroughlydepictthelateralvariationsofshearwavevelocitiesindifferentdepthranges.WiththedeterminedpurepathdispersionswefurtherinvertedfortheSwavevelocitystructuresalongtwoprofilesfromeasternTibettoPacificOceanandfromSouthChinaSeatoMongolia.Itisfoundthatthelateralheterogeneityisobviousdownto400kmdepth,andthevelocitystructuresarecorrelatedwithtectonicunitsinthestudyarea.

简介：1861M6。0地震发生在Pulandian的东方是有M6的另一强烈地震。0除1975HaichengMT以外。在Liaodong半岛的3地震。通过重复调查，1861地震的震中在Gupao被定位，Pulandian的村庄东方。基于损坏调查和现代仪器的地震数据，这项活动和Jinzhou差错，Pulandian海湾差错和趋势NW的地震风险的精确地点的分析Pulandian差错被分析。并且由比较在Pulandian和Haicheng之间的深seismogenic环境，，它被发现那neogenic活跃差错，趋势NW差错，与Jinzhou差错结合了，有更高地震的风险。趋势NW差错是1861M6的seismogenic结构。0地震。并且作为在Liaodong半岛的一个主要差错，Jinzhou差错控制了这个区域的seismicity。Pulandian海湾差错是相对不活跃的，与弱seismicity，并且对地震无关。

简介：AnumberofaftershocksoftheMay10th1997,Zirkuh(Ghaen-Birjand)destructiveearthquakehavebeenusedtoinvestigatetheanisotropyintheuppercrustbyobservingshearwavesplitting.Particlemotiondiagramandaspectratiomethodswereusedastwodifferentapproachestoobtainsplittingparameters.Clearshearwavesplittingwasobservedontherecordsoftheselectedaftershocks,indicatingthatthemediaintheregionwashighlyanisotropic.Byusingparticlemotionmethod,thedirectionoffastshearwavewasfound22°N±19°E,whilethedelaytimebetweenthefastandslowshearwaveswasobtainedtobe(65±16)ms.Byaspectratiomethod,thedirectionoffastshearwavewasdeterminedtobe35°N±18°Eandthedelaytimebetweenfastandslowshearwaveswasfoundtobe(49±10)ms.Forasimplehorizontallayerwithathicknessabout5kmanduniformlydistributedanisotropy,astressalignedcracksmodelwasusedandtheresultwasinterpretedintermsofverticalalignedcracksinthedirectionofN22°E,havingadensityabout0.01.Itisassumedthatcracksarefluid-filledsincetheyarelocatedintheuppercrust.Finally,byusingHudsoncracksmodelforthreecrackdensities0.005,0.01,0.03,thevelocitycurvesofshearwavewereplottedasafunctionofanglebetweenthesymmetricalaxisofcracksandtheazimuthofsourcetoreceiver.Itwasconcludedthatwhenshearwavewaspolarizedparalleltothecracksurface,thevelocitywasuniform,butthevelocitycurvevariedclearlyifshearwavewaspolarizedperpendiculartothecracksurface.

简介：TheIndiaplate(scontinuousmotiontothenorth,theconvectiveremovaltothethickeninglithospherecausedbysmall-scalemantleconvectionandtheeffectofdenudationontheupliftedplateauareregardedasmaindrivingforcesthatmakethepatternsofstressfieldofEastAsiacontinentatpresenttime.ThemethodofnumericalsimulationisusedtostudythedeformationandthestressfieldofEastAsiacontinentunderdifferentboundaryconditions,differentdenudationcoefficientsanddifferentrockmechanicsparameterswithinatrapezoidgeologicalframe.Comparingwiththeresultsobtainedbymodernspacegeodetictechnique(suchasGPS)theresultsderivedfromseismologicaldatashowthatthepredicteddatabyourmodelcanfitthemverywell.Thedegreeofthefitnessinthewestisbetterthanthatintheeast.TheseresultsimplythatthemaindrivingforceofthedeformationandthestresspatternsofthewestpartofEastAsiacontinentmaycomefromthecollisionandcompressionbetweentheIndiaandtheEurasiaplates.TheinteractiontothePacificandthePhilippinesplatesintheeastpartneedtobeconsidered.Italsoshowsthattheconvectiveremovaltothethickeninglithospherecausedbysmall-scalemantleconvectionandtheeffectofdenudationcannotbenegligibleintheevolutionofthestresspatterns.

简介：TheEastKunlunfaultzoneislocatedinthenorthernmarginoftheBayanHarblock.ThestudyofearthquakerupturebehaviorinthefaultzoneisofimportanceforunderstandingthefutureseismicriskinnorthwestSichuan.Anumberofgeologicalfieldinvestigations,typicalmicrotopographyDGPSmeasurementsandsampledatingshowthattheearthquakeactivityoftheEastKunlunfaultzoneextendstothenorthboundaryofZoigebasin,asegmentknownastheLuochasegmentofTazangfault.Inthesatelliteimage,thesegmentisseenclearlyasgrayandyellowstrips.Theearthquakedeformationzonemainlyfeaturesfaultscarp,valleysontheslope,offsetgulliesandterraces,lineardistributionofplants,waterfall,faultspring,faultsagpond,andlandslide,collapseandtalusassociatedwithsurfacerupturing.Thesephenomenaaredistributedintermittentlyalongthere-existingfaultandforma～50km-longinverseL-shapeddeformationzone.Faultactivitiescausedleft-lateraloffsetofgulliesandterraces,withhorizontaldisplacementconcentratedat5.5m~6m,18m～23m,68m～75m,and200m～220m,respectively.Therecentearthquakeoccurredbetween340±30～500±30BP.Themacroepicenterislocated5km～7kmnorthwestofBenduovillage,withmagnitudeofMW7.3～7.4,maximumcoseismicdisplacementof6m,horizontaldisplacement5.5m～6mandverticaldisplacement0.2m～0.5m,beinginaproportionof5∶1～10∶1.ThesephenomenashowthattheTazangfaultisthecausativefaultofthisearthquake.ThefaultisaHoloceneactivefaultandwasdominatedrecentlybyleft-lateralmovementwithasmallamountofthrustcomponentundercompressiveshearstress.ThischaracteristicissimilartothemovementinothersegmentsoftheEastKunlunfaultzone.Theresultsofthisstudysupportthe"continentalescape"model.

简介：Inthispaper,thecorrespondingrelationoftheevolutionarycharacteristicsofgeodeticdeformationfieldswithseismicactivityformorethan20yearsintheNorth-SouthseismiczoneandEastofQinghai-XizangMesshasbeeninvestigated.Notonlyisgeodeticdeformationinnon-homogeneityforthespace-timedistributionbutalsodeformationfieldsareinmacroscopicsimilarityfortheidenticaltimeinterval.Theinheritedtectonicmovementisatotaltendencyofrecentcrustalmovement,andthemotionmodeisinundulations.Therearestagesofaccumulationandrelease-adjustingofstrainenergyincrustalmovementprocesses,whichmaybethedynamicmechanismofrelativelyquietandactiveseismicity.Theanalysisofthecrustalmovementtendencysince1991isofsomesignificanceforjudgingthestressstateandthelargeseismicsituationinthearea.

简介：Onthebasisoftherealityofrecenttectonicmovementanddiscardingsuchaviewpointthattheisostaticadjustmentonlyresultsfromexcessiveorinsufficientcompensation,wehavediscussedthetectonicstresscausinginequalityandregardedtheisostaticanomalyasaloadontheearth(sinterior,thustheearth(sinnerstresscanbecalculated.TheresearchresultsshowthatintheEastChinaSeaanditseasternmarginalseasthechangeoftheverticalstressderivedfromtheisostaticgravityanomalyismoremarkedthanthatofthehorizontalstress.AlongtheRyukyutrenchthereisanenhancementofverticalstressby5MPa,whichevidentlyreflectstheeffectofplatesubduction.Oncontrary,alongtheislandarctothenorthwestofthetrenchtheverticalstressweakensbyabout5MPa.Thehorizontalstressesineasternandwesternpartsareobviouslydifferent,theeastwestwardstressontheoceaniccrust(xisnegative(whilethepressureispositive)butonthecontinentalcrustispositive.Thesefactsindicatetheeffectofcompressionbetweenplates.

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