简介：Inthispaperchangesinfocalmechanisms,parametersofwavespectra,andstressdropsfortheMS=5.0foreshockandMS=6.0mainshockinFebruary2001inYajiangCounty,Sichuan,andseismicityinepicentralregionarestudied.ComparisonoffocalmechanismsfortheYajiangearthquakeswithdistributionpatternsofaftershocks,thenodalplaneI,strikinginthedirectionofNEN,oftheYajiangM=5.0eventischosenasthefaultingplane;thenodalplaneII,strikinginthedirectionofWNW,oftheM=6.0eventasthefaultingplane.Thestrikesofthetwofaultingplanesarenearlyperpendiculartoeachother.ThelevelofstressdropsintheepicentralregionbeforetheoccurrenceoftheM=6.0earthquakeincreases,whichisconsistentwithincreaseofseismicityintheepicentralregion.TheratedecayoftheYajiangearthquakesequence,changesinwavespectraforforeshocksandaftershocks,andfocalmechanismsarecomplex.

简介：ShearwavesplittingisstudiedbasedonthedigitalwaveformsofthreeseismicstationsDJS,SZDandWUJ,whichweresetupaftertheJiujiang-RuichangMS5.7earthquakeofNovember26,2005aroundtheepicenterarea.TheresultshowsthatthetimedelaysofslowshearwavesoftheDJSstation,whichisnotfarfromtheepicenterandwherethedistributionoffaultsiscomplexnearthestation,arerelativelylargerandthepolarizationdirectionsoffastshearwavesarenotconcentrated;thepredominantpolarizationdirectionoffastshearwavesofWUJstation,withsinglefaultdistributednearby,hasadifferenceof35°tothestrikeofthefaultandisinconsistentwiththedirectionofregionalprincipalcompressivestress.ThepredominantpolarizationdirectionoffastshearwavesofSZDstationwithnofaultsnearbyisinaccordancewithregionalprincipalcompressivestress.Thereisnoobviousregularrelationshipshipbetweenthedelaytimeandthefocaldepth.

简介：OnAug.8,2017,anMS7.0earthquakestruckJiuzhaigou,acountyofSichuanprovince,China.Anumberofinvestigationsandstudieshavebeenconducted,someofwhichinvolvedlocalvelocitymodels.However,thesuitabilityofthesemodelshasnotbeenproperlyaddressed.Herewecollect11already-existingmodels,includingthoseusedinstudiesofthe2017MS7.0Jiuzhaigouearthquake,choose10localstationssurroundingtheearthquake,andemploythesametechnique(TRIT)torelocatethehypocenter.Andfurthermore,wechooseamoresuitablemodelfromthe11already-existedmodelsbyanalyzingtherelocationprocessandtherelocatedresultsforreasonability.Finally,ourconclusionisthatthemodelFang2018ismoresuitableandthehypocenterparameters,103.801°E,33.192°Nand15.8kmforlongitude,latitudeanddepth,respectively,and2017-08-0813:19:46.66foritsorigintime,basedonthismodelshouldberecommendedforthe2017MS7.0Jiuzhaigouearthquake.

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简介：分析认为玉树地震台井水温2015年3月出现的异常很可能与尼泊尔8.1级地震有关。进一步分析玉树井水温自2007年以来的观测数据,发现这口井在2008年5月12日四川汶川Ms8.0级地震、2009年11月12日德令哈Ms5.0级地震和2010年4月14日青海玉树Ms7.1级地震前均出现较明显的前兆异常,分析这口井对应不同地震的异常曲线形态,得出这口井在尼泊尔地震前的异常形态与汶川、德令哈和玉树地震前的异常形态不同的结论。

简介：TheJuly3,2015PishanM_S6.5earthquakeoccurredintheintersectionareaoftheTarimblockandWestKunlunblockwherethemoderate-strongearthquakeshavebecomeactiveinrecentyears.Thispaperhasstudiedtheseismicityparametersoftheearthquakesequencessuchastheb-valueinthePishanregionanditsvicinity.Inaddition,wealsorelocatedtheaftershocksofthePishanM_S6.5earthquakeusingtheseismicphasereportbythedouble-differencemethod.ThetemporalandspatialvariationcharacteristicsofthePishanearthquakesequenceintherupturezoneareanalyzed.Thestudyisofgreatsignificanceintheseismichazardassessmentinthisregion.

简介：在掌握西藏南部（26°～32°N，78°～98°E）19次历史地震数据后，从时间对称性方面研究该区域历史地震发生规律，分析未来地震发生的可能时间，从而为西藏地震灾害的监测提供一定的依据。从三元、四元和五元可公度信息提取法和蝴蝶结构法进行分析，得出未来10年内，西藏南部Ms≥6．6级地震的信号在2012年、2013年和2015年较强，有发生6．6级以上地震的可能。

简介：TheYajiangearthquakesequencein2001,withthemajoreventsofMs5.1onFeb.14andofMs6.0onFeb.23,aresignificanteventsintheSichuanregionduringthelast13years.Eighty-eightearthquakesinthesequencewithatleast5distinctonsetparametersforeachrecordedbytheSichuanSeismicNetworkintheperiodofJan.1throughJune30,2001werechosenforthisstudy.TheeventsarerelocatedandthefocalmechanismisderivedfromP-waveonsetsfor13eventswithrelativelylargermagnitudes.Thefocaldepthofallearthquakesfallbetweenarangeof2kmto16km,withdominantdistributionbetween9kmto11km.Theforeshocks,theMs5.1earthquakeandtheMs6.0earthquakeandtheiraftershocksarealllocatedclosetotheZihefaultandthedominantepicentraldistributionisinNWdirection,identicaltothatofthefault.ThefracturesurfaceofthefocalmechanismisdeterminedinaccordancetothemasstransferorientationintherecentearthdeformationfieldintheYajiangregion.ThePaxesoftheprincipalcompressivestressinfocalmechanismsolutionsofthe13eventsshowbiggerverticalcomponents,andthehorizontalprojectiontrendingSE.Theearthquakesareofleft-lateral,strike-slipnormal,andnormalstrike-sliptypes.TherupturesurfaceofmostearthquakesstrikeNW-SE,dippingSW.Basedontheaboveinformation,weconcludethattheZihefaultthatcrossestheearthquakearea,strikingNWanddippingSW,istheseismogenicfaultfortheYajiangearthquakesequence.

简介：Inordertostudythespatiotemporalevolutionoftheprecursoryanomalies10yearsbeforetheWenchuanMS8.0earthquakein2008,theepicentraldistanceoftheprecursoryanomaliesiscalculatedbyusingthegeometriccenteroftheruptureregionandtheellipticalcenterlineoftheaftershockregion.Theresultshows,precursoranomaliesgraduallyincreasedabout2yearsbeforetheWenchuanearthquake.Theratioofabnormalitemsisgreaterthan25%inthenearsourcearea(abouttwicethesourcescale)and17%-24%intheremotearea(about3-5timesthesourcescale).Therearethreedifferentstagesofspatiotemporalevolutionofprecursoryanomalies.Duringtheαstage(includingα1andα2,between700to3000daysbeforethemainearthquake),theanomaliesaremainlydistributedinthesouthwestandnorthwestareaoftheWenchuanaftershocksarea.Itisshownthattheprecursorsofthefarsourceregionandthenearsourceareahavethecharacteristicsofoutwardexpansion.Duringtheβstage(between300to700daysbeforethemainearthquake),theanomaliesaredistributedinthesouthwestandnorthernregionoftheaftershockregion,showingalargerangeofanomalies.Duringtheγstage(includingγ1andγ2,300daysbeforethemainearthquake),therangeofanomalydistributioniswide,andtheanomaliesaredistributedinthesouthwestandnortheastoftheaftershockarea.Theanomaliesconvergedtoepicenter(γ1)inthefarsourceregionandexpandoutwards(γ2)inthenearsourceregion.Resultsoftheexperimentalstudyandmechanicalanalysisofearthquakepreparationprocessindicatethatthethree-stagecharacteristicsofprecursoryanomaliesintheprocessofearthquakepreparationmaybecontrolledbytheseismogenicbody,whichisaformofexpressionintheprocessofearthquakepreparationandauniversalfeatureduringtheearthquakepreparationprocess,whichhasacertainguidingroleinearthquakeprediction.

简介：TheYutianearthquakewithM_S7.3happenedonFebruary12,2014.Theprecursormonitoringabilityisweakinthatarea.Wefoundtendencyanomaliesandmiddle-andshort-termanomaliesfrommetalpendulumtiltmeasurementsinHotanseismicstationbeforetheearthquake.AndwealsocomparedtheanomalieswiththatoftheM_S7.3YutianearthquakeonMarch21,2008.Thetendencyanomaliesmeasuredbythemetalpendulumtiltmeterappearedsince2012astiltingeastward.Whilethemiddle-andshort-termanomalieswerecharacterizedbyacceleration,pauseandrapidchangeoftiltrateintwodirections.Thetendencyanomaliesofmetalpendulumtiltrecordsarethesamebeforethetwoearthquakes.Theybothhappenedintheeastdirection.However,therearedifferencesinduration,characteristicandearthquakeintervalsforthemiddle-andshort-termanomalies.

简介：2014年8月3日发生的鲁甸地震是我国继2013年芦山地震之后的又一次破坏性浅源地震,造成了严重的人员伤亡和工程结构破坏.本文处理了我国数字强震动台网捕获的60余组主震三分量强震动记录,绘制了震中附近区域的峰值加速度等值线图,长轴沿西北-东南方向展布.通过与中国西部常用衰减关系的对比,发现各模型的预测值均不同程度高估了峰值加速度、峰值速度的观测值.最后以水平向峰值加速度较大的三个典型台站为例,详细调查了附近建筑的破坏情况,结合宏观烈度分布结果,分析了地震动特征与震害的相关性.

简介：M_s6.8地震在Xinjiang.Themacroseismic在Wuqia区域发生在10月5,2008日震中位于Kyrghyz共和国的Nula村庄，在Xinjiang.The震中紧张的WuqiaYierkeshitan港口的7km西南是度(外面的边阶)紧张的.The区域并且是7354km2和1031km2，respectively.This地震事件在earthquake.stricken区域与趋势NEKzikeaerkate差错belt.Buildings的运动被联系被损坏或影响到某个exte

简介：UsingthedigitaltelemetricseismicwaveformdataofChengduandKunming,thisarticlestudiesthefocalmechanismsolutionsandtheapparentstressvaluesofalargenumberofsmallearthquakes,andthenanalyzesthedynamicvariationofregionalstressfieldsandthespatio-temporaldistributionofapparentstressvalues.TheannualvariationvaluesoftheazimuthofaverageprincipalstressfieldbeforetheMay12,2008M_S8.0WenchuanearthquakeintheSichuan-Yunnanregionwere58°from2003to2004,85°from2003to2005,61°from2006to2007and90°from2006toApril2008respectively.Inrecentyears,deflectionordisturbancesoccurredintheazimuthoftheaverageprincipalstressfieldintheSichuan-Yunnanregion.AnalysisshowsthatthismayberelatedtothechangeofstressfieldstatesofcrustalblocksbeforeandaftertheDecember26,2004M_S9.0Sumatraearthquakeandthe2008M_S8.0Wenchuanearthquake.Theratioofthrust-typeearthquakesintheSichuan-Qinghaiblockwasonthehighersideintheperiodfrom2006to2007,andthesourcefaultingtypeoftheregionalmoderateandsmallearthquakeshadchangedbeforetheM_S8.0Wenchuanearthquake.ThechangeofstateofthestressfieldisconsistentwiththechangesinblockdisplacementfieldsrevealedbyGPSdataandthecrustalshorteningvelocityverticaltotheLongmenshanfaultzone.Basedontheradiationenergycalculatedfromallbandsoftheseismicwaveform,thevalueofapparentstressσ_appisobtained.Thefluctuationshapeofthefittingtrendoftheapparentstressisrelatedtotheintensityofregionalseismicity.Itrevealsthatthemicro-dynamicfluctuationprocessoftheregionalstressvalueissimilartotheazimuthtransitionoftheregionalprincipalcompressivestressfield,whichcanbeusedtoprobeforpregnantphysicalprocesses.Areaswithahighervalueofapparentstressσ_apparepossibleareasofpotentialseismicrisk.Itcanbeseenfromthespatialdistributionofthemediumandshort-termapparen

简介：Aftertheoccurrenceofanearthquake,strongmotionobservationnetworkscanrecordgroundmotionatdistributedobservationstations.Basedonthegroundmotionparametersfromtheserecords,thespatialdistributionofseismicintensitycanbequicklydetermined,andthedegreeofdamageindifferentareascanbeestimated.Thisinformationprovidesthetechnicalbasisfortheemergencyresponse,soastoensurethatrescueteamscanreachextremeearthquakeareasandcarryoutthesearchandrescueoperationinanaccurateandtimelymannertoreducecasualtiesandpropertyloss.Inthispaper,weintroduced7intensityalgorithmsandcomparedtheresultswiththerecordsoftheJiuzhaigouMS7.0earthquake.Wefoundthatthedifferencesbetweentheinstrumentalintensitiescalculatedbyeachmethodandthemacrointensitieswerewithina1-degreerange,whichsuggestedgoodpracticalityofthesedifferentmethods.Theresultscalculatedbytheindustrialstandards-basedcalculationmethodandtheintegratedtestshowedgoodconsistency.

简介：TheWenchuanMS8.0earthquakeoccurredontheLongmenshanfaultwhichinclinesatadipangleexceeding60degrees.Sincemostthrustearthquakesoccuronfaultswithdipanglesofabout30degrees,itisenigmaticwhytheWenchuanearthquakeoccurredonsuchasteepfault.InthisstudyweuseasimplefiniteelementmodeltoinvestigatehowthestressstateinthefaultchangeswiththevariationofPoisson’sratio.Theresultsshowthat,withthePoisson’sratiointhefaultincreasing,themagnitudesoftheprincipalstressesincreaseandthemaximumshearstressdecrease,and,especially,theanglebetweenthemaximumprincipalstressandthefaultplanedecreases,whichwillenhancethedrivingforcetoovercomethefrictionalresistanceonthefault.TheincreaseofPoisson’sratiointhefaultmaybeanimportantfactortoaffecttheoccurrenceofthefaultearthquakeswithlargeanglesbetweenmaximumprincipalstressandfaultplane.

简介：Inthispaper,statisticsaretakenontheco-seismicresponseofundergroundfluidinYunnantotheNepalM_S8.1earthquake,andtheco-seismicresponsecharacteristicsofthewaterlevelandwatertemperatureareanalyzedandsummarizedwiththedigitaldata.TheresultsshowthattheNepalM_S8.1earthquakehadgreaterimpactontheYunnanregion,andthemacroandmicrodynamicsoffluidsshowedsignificantco-seismicresponse.Theearthquakerecordingcapacityofwaterlevelandtemperaturemeasurementissignificantlyhigherthanthatofwaterradonandwaterqualitytothislargeearthquake;themaximumamplitudeanddurationofco-seismicresponseofwaterlevelandwatertemperaturevarygreatlyindifferentwells.Thechangingformsaredominatedbyfluctuationandstepriseinwaterlevel,andarisingorfallingrestorationinwatertemperature.Fromtherecordsofthemainshockandthemaximumstrongaftershock,wecanseethatthegreatermagnitudeofearthquake,thehigherratiooftheoccurrenceofco-seismicresponse,andinthesamewell,thelargertheresponseamplitude,aswellasthelongertheduration.Theamplitudeanddurationofco-seismicresponserecordedbydifferentinstrumentsinasamewellaredifferent.Watertemperatureco-seismicresponsealmostoccurredinwellswithwaterlevelresponse,indicatingthatthewellwaterlevelandwatertemperaturearecloselyrelatedinco-seismicresponse,andthewellwatertemperatureseismicresponsewascausedmainlybywellwaterlevelseismicresponse.

简介：TheinvestigationondamagestofrozensoilsitesduringtheWestKunlunMountainsPassearthquakewithMs8.1in2001showsthatthefrozensoilintheseismicareaiscomposedmainlyofmoraine,alluvialdeposit,diluvialdepositandlacustrinedepositwiththedepthvaryinggreatlyalongtheearthquakerupturezone.Thedeformationandruptureoffrozensoilsitesaremainlyintheformofcoseismicfracturezonescausedbytectonicmotionandfissures,liquefaction,seismicsubsidenceandcollapseresultingfromgroundmotion.Theearthquakefracturezonesonthesurfacearemainbrittledeformations,which,undertheeffectofsinistralstrike-slipmovement,arerepresentedbyshearfissures,tensionalcracksandcompressivebulges.Thedistributionandconfigurationpatternsofdeformationandrupturesuchasfissures,liquefaction,seismicsubsidenceandlandslidesareallrelatedtotheambientrockandsoilconditionsoftheearthquakearea.Thedistributionofearthquakedamageischaracterizedbylarge-scalerupturezones,rapidintensityattenuationalongtheQinghai-Xizang(Tibet)Highway,wherebuildingsdistributeandpredominanteffectofrockandsoilconditions.

简介：ThepaperdiscussesquantitativelytheinfluenceoftheYutianMS7.4earthquakeofMarch21,2008andWuqiaMS6.9earthquakeofOctober5,2008onregionalseismicityinXinjiang,andexplainsprimarilythepossiblereasonofearthquakeactivityfeatureinXinjiangaftertheYutianMS7.4earthquakebyanalyzingthestaticCoulombfailurestresschangeproducedbytheYutianMS7.4earthquakeandWuqiaMS6.9earthquake,andtheseismicityfeatureofMS≥3earthquakesinthepositiveCoulombstresschangeregionofKashi-Wuqiajointregion,thecentralsegmentofTianshanMountainandKalpinblock.TheresultshowsthattheYutianMS7.4earthquakeofMarch21,2008,mayencouragetheWuqiaMS6.9earthquakeofOctober5,2008,andtheYutianMS7.4earthquakeandWuqiaMS6.9earthquakemaychangetheseismicitystateinthecentralsegmentofTianshanMountain,KalpinblockandKashi-Wuqiajointregion,andencouragethesubsequentMS≥3earthquakes.

简介：Bycalculatingtheazimuth,phaseangleandchangerateoftidalforce,andcontrastingtheirrupturetypes,wefindthatin6of11reversefaultingearthquakes,theanglesbetweenthedirectionofthehorizontaltidalforceandcompressiveprincipalstressarewithin33°,theverticalphaseanglesofall8strike-slipearthquakesareintheupwardpeaksectionandtheverticalphaseanglesoftwoextensionalnormalfaultingearthquakesareinthedownwardpeaksection.Accordingtotheabovestatistics,themechanismoftidalforcetriggeringoftheWenchuanMS8.0Earthquakeanditsstrongaftershocksisdiscussed.

简介：BasedontheanalysisofcoseismicdeformationinthemacroscopicepicentralregionextractedbyDifferentialInterferometricSyntheticApertureRadar(D-InSAR),andcombinedwiththeseismicactivity,focalmechanismsolutionsoftheearthquakeandfieldinvestigation,thecharacteristicofcoseismicdeformationofMS=8.1westernKunlunshanPassearthquakein2001wasresearched.ThestudyshowsthatitsepicenterliesinthenortheastsideofHohSaiHu;andtheseismogenicfaultinthemacroscopicepicentralregioncanbedividedintotwocentraldeformationfields:thewestandeastsegmentswiththelengthsof42kmand48km,respectively.Thewholefaultextendsabout90km.Fromthedistributionofinterferometryfringes,thecharacteristicofsinistralstrikeslipofseismogenicfaultcanbeidentifiedclearly.Thedeformationsonbothsidesofthefaultaredifferentwithanobviouslyhighervalueonthesouthside.Inthevicinityofmacroscopicepicenter,themaximumdisplacementinlookdirectionisabout288.4cmandtheminimumis224.0cm;themaximumsinistralhorizontaldislocationofseismogenicfaultnearthemacroscopicepicenteris738.1cmandtheminimumis551.8cm.