简介:Basedon49digitalseismogramsrecordedby73seismicstationsintheJiangsuTelemeteredSeismicNetwork,thepaperusesAtkinson'smethodtocalculatetheinelasticattenuationcoefficientoftheJiangsuarea.Wefindthatthefrequency-dependentQintheJiangsuregionisQ(f)=272.1·f~(0.5575).WealsouseMoya'smethodtoinvertthe63stations'siteresponses.Theresultsshowthatthesiteresponsesofthe25stationsinJiangsuareapproximately1atarangebetween1Hzand20Hz,whichisconsistentwiththeirbasementsonrocks.Theresponsecurvesofthesiteresponsesofthe14undergroundstationsaresimilartoeachother.Theirsiteresponsesshowanamplificationatlowfrequenciesandminimizationathighfrequencies.ThecalculationoftheBrunemodelonthewaveformdataofM_L≥2.5earthquakesfromJiangsuDigitalSeismicNetworkbetweenOctober2010andMay2015intermsofseismicsourceparametersof58seismicwavesshowsthattherearegoodcorrelationsbetweenseismicmagnitudeandothersourceparameterssuchasseismicmoment,sourceradiusandcornerfrequency,whilethecorrelationsbetweenseismicmagnitudeandstressdrop,andstressdropandsourceradiusarenotsogood.
简介:Thisstudyinvestigatestheeffectivenessofthenon-smoothsemi-activecontrolalgorithmonsuppressingthevibrationperformanceofabuildingstructuresubjectedtoseismicwaves.AccordingtotheLyapunovstabilitytheory,ithasbeneproventhatthenon-smoothsemi-activecontrolalgorithmcanachieveafinite-timestabilityofthevibrationrelativetotheisolationlayerofabuildingstructure.Throughnumericalsimulationoftwobuildingswithdifferentparameterssubjectedtotheinputofaseismicwave,thevibrationconditionsofpassivecontrol,LQRsemi-activecontrolandnon-smoothsemiactivecontrolarecomparedandanalyzed.Thesimulationresultsshowthatthenon-smoothsemi-activecontrolalgorithmhasabetterrobustnessandeffectivenessinrestrainingtheimpactofearthquakesonthestructure.
简介:WeuseddatafromtheXinjiangDigitalSeismicNetworkandPSD(PowerSpectralDensity)methodtoperformnoiselevelassessmentforsixstations.Wecalculatedthemedianofthepowerspectraldensitytoevaluatethenoiselevelofdifferentstations.Afterthecomparisonofthepowerspectraldensityofdifferentstationsandtheairgunsignalrecognition,wefoundthatnoiselevelofstationswithrecognizableairgunsourcesignalsislowerthanthatofstationswithoutrecognizablesignals.Thelargestdifferenceofthepowerspectraldensityis40dB,andthesmallestis15dB.Finally,wefoundthatthefailuretorecognizethesignalofairgunsourcesatsomestationsisduetothenoiselevel.
简介:Inordertodeterminethedegreeofreturning-to-zerooftemperaturesofdeformedcalcite,aseriesofrock-breakingexperimentsweredesignedtotestcalcite-richlimestonesamplesunderfixedconfiningpressuresanddifferenttemperatures.Theconsolidateddeformedsamplesintheirinitialstatewereobservedunderamicroscopeandthemicroscopicindicatorsindifferentzero-returningstateswereputforward,thusprovidingamicroscopicfoundationforevaluationofreliabilityofdatingvaluesofdeformationincalcite.Atlast,thecorrectionofdatingvaluesofdeformationforsampleswhosetemperaturehasnotyetreturnedtozeroisdiscussed.
简介:Thepseudoexcitationmethod(PEM)hasbeenimprovedintoamorepracticalform,onwhichtheanalyticformulaeofseismicresponsepowerspectraldensity(PSD)ofsimplifiedlarge-spanstructuralmodelshavebeenderived.TheanalyticformulaeandnumericalcomputingresultsofseismicresponsePSDhavebeenderivedtostudythemechanismofmulti-supportexcitationeffects,suchasthewave-passageeffectandincoherenceeffect,fortheseismicresponseofmultiandlarge-spanstructures.Byusingamulti-spantrussasanexample,theinfluenceofmulti-supportexcitationeffectsontheseismicresponseofsuchstructuresisstudied.
简介:TheDeepSeismicSounding(DSS)projectscarriedoutfromthe1970sinthelowerYangtzeregionanditsneighboringareawerereviewedinthispaper,thenthebasicwavegroupfeaturesofthosewideanglereflection/refractionrecordsections,andofthecrustalstructurearesummarized.Itshowsthattherewereintotalfiveclearwavegroupsontherecordsections,whichincludethefirstarrivalPg,thereflectionP1fromthebottominterfaceoftheuppercrust,thereflectionP3fromthebottominterfaceofthemiddlecrust,thestrongreflectionPmfromtheMohoboundary,andtherefractionPnfromuppermostmantle.Ingeneral,thesephasesareeasilyconsistentlytracedandcompared,despitesomefirstarrivalsbeingdelayedorarrivingearlierthannormalduetotheshallowsedimentarycoverorbedrocks.Inparticular,intheDabieMountainregiontheseismiceventsofafewgatheredshotsalwayshaveweakreflectionenergy,aretwisted,orexhibitdisorganizedwaveforms,whichcouldbeattributedtothedisruptionvariationsofreflectiondepth,thebrokenMoho,andthediscontinuityofthereflectionboundarywithincrust.Theregionalcrustalstructuresarecomposedoftheupper,middleandlowercrust,ofwhichthemiddleandlowerlayerscanbedividedintotwoweakreflectionones.ThecrustalthicknessoftheNorthChinaandYangtzeplatformare30km-36km,andtheMohoexhibitsaflatgeometrydespitesomelocaluplifts.Theaveragepressurevelocityinlowercrustbeneaththistwotectonicareais6.7±0.3km/s.Nevertheless,beneaththeDabieshanareathecrustalthicknessis32km-41km,theMohobendsdownsharplyandtakesanabrupt4km-7kmdislocationintheverticaldirection.TheaveragepressurevelocityinthelowercrustbeneaththeDabieshanareais6.8±0.2km/s.
简介:这个地点和结构的参数无常的动态效果的考虑被标准在大多数国家为核电厂(NPP)要求。抗地震的标准提供二个基本方法分析参数无常。手工地直接处理计算地板反应系列(皇家学会会员)确定的途径珍视是第一个方法。第二个方法是执行概率统计的FRS的分析根据蒙特卡罗方法结果。二个方法能仅仅反映不明确的参数的全面效果,并且结果不能为某个参数影响和贡献被屏蔽。在这研究,基于NPP的地板反应系列的动态分析,为各种各样的不明确的参数的估计的影响的一个全面索引被介绍并且推荐,包括关联系数,回归斜坡系数和旋风秋千。在NPP地震标准补偿指导的缺乏,建议方法能有效地被用来从敏感,尖酸和统计秋千的方面评估各种各样的参数的贡献关联。最后,例子被提供从系统、直觉的观点验证指示物的集合,例如NPP的皇家学会会员的结构参数和贡献的影响的无常。这个索引对参数的不同类型敏感,它为评估为NPP要求的抗地震的参数提供一种新技术。
简介:Inviewofthecorrelationbetweentectonicactivityandseismicity,thestrongearthquakeriskintheNorth-SouthSeismicBeltarousedwideconcernafterthe2014YutianM_S7.3earthquake.UsingtheseismiccatalogoftheChinaEarthquakeNetworksCenter,theBenioffstrainratiointheNorth-SouthSeismicBeltiscalculatedin30daysbeforeandaftertheMarch21,2008andFebruary12,2014YutianM_S7.3earthquakes.Resultsshowthatinayearafterthe2008YutianM_S7.3earthquake,M>5.0earthquakesalloccurrednearthehighstrainratioareaorthejunctionbetweenthelowandhighstrainratioareas,theactivityofstrongearthquakesobviouslycoincideswiththehighstrainratioarea,whichindicatesthattheseareashaveahigherstresslevel.TheYutianearthquakespromotedthereleaseofsmallearthquakesinthehighstressareas.Thisresearchisofcertainindicatingsignificancetothestudyofsubsequentstrongearthquakesofthisregion.
简介:关于在在中国的纵贯的地震的带和基于地理信息,系统(GIS)被做了的中央orogenic带的连接区域的差错和seismicity之间的关系的研究。为每在这个区域的16个差错,我们造一个25km缓冲区地区和使用覆盖分析在每个差错上调查seismicity和它的特征。结果作为follows:the揭开主要地震差错西方的片断西方Qinling差错,Lixian-Luojiabao差错的西南的片断,Lintan-Dangchang差错的东南的片断,Wenxian差错的西南的片断,Huya差错,和Xueshan差错北边。最活跃的差错是Huya和Xueshan差错,然后,Tazang差错,Lixian-Luojiabao差错和Guanggaishan-Dieshan的北山麓指责。研究地区能根据焦点的深度被划分成四个区域,它向南向北变得更深从到。焦点的深度的侧面显示几何学和差错的机械性质,并且进一步揭示西藏的高原的东方挤出和群众的向东南的逃跑的运动模型,因此在这个区域对地震和危险缓解为保护提供基础。