简介:江苏高邮、宝应Ms4.9级地震在极震区造成了数10间农村民居不同程度和不同方式的破坏,出现人员伤亡。震后对地震灾害现场进行震害调查与破坏原因研究,典型的震害特征包括砖砌体、砖木和砖混结构房屋局部倾倒、墙体贯通开裂、房顶瓦片掀翻和烟囱倒塌等。农村民居遭到破坏的主要因素包括:选址不当、施工质量较差、砂浆强度不够、缺少圈梁和构造柱等。同时,分析了竖向地震作用和鞭梢效应等地震效应,讨论了砖砌体和砖混结构抗震设计的加固方法和改善抗震性能的构造措施等,为农村民居的抗震设防和减轻震害损失等提供参考。
简介: Introduction Withrapiddevelopmentandadvancementofeconomyandsociety,lotsofcitygroupsorcitybeltswithex-tra-largecitiesastheircentershavebeenformedinChina.Theregionsthesecitygroupslieinusuallyhavewell-developedeconomy,densepopulation,andareregionalpoliticsandculturecenters.Somegroupslieintheregionswithhighlevelofearthquakeactivity,suchastheSurroundingCapitalCityGroupwiththecentersofBei-jingandTianjin.Oncealargeearthquakeoccurs,itsinfluencewillspreadtoveryextensiveregionanditsdisasterwillbetremendoustoo.Soearthquakeresistanceanddisastermitigationofcitygroupwillbeverysignificantissue.Thecitiesinagrouphaveclosedistancewitheachother;theycancarryoutunifiedpreparationfordisasterasonewholeandreducetheheavyloadofsinglecitybeforeanearthquake,andhaveanadvantageofpromptmutual-aidafteranearthquakebecauseofclosedistance.Itisespeciallysignificanttomitigatetheloseoflives.Oneimportantpreconditionisthatallthecitiesinonegroupcannotbeexposedtothesamelevelofdestroyduringoneearth-quake.Sothedivisionofcitygroupintheregionwithdensecitiesdistributionshallbeverysignificanttotheemergentmutual-aidinearlytimeafteralargeearthquake.Forthisgoal,thecharacteristicsandcorrelativityofearthquake′simpactoncitiesinonegroupneedtoclearlybeconsidered.Thecitieswithsimilarfeaturesandstrongcorrelativityofhistoricalearthquakeinfluencehavelargechancetosuffersameleveldestroyduringthefuturestrongearthquakeandaredisadvantagetoprovidemutual-aidandshallnotbedividedintoonegroup. ……
简介:TheemergenceofZhangHeng’sseismoscopehasaprofoundhistoricalbackground.ThispaperintendstoexploretheformationandmaterialbasisofZhangHeng’sscientificthought.Itappearsthatthesimpleintentionof"observingvisionsanddistinguishinggoodfortuneormisfortune"washismotivationtodeveloptheseismoscope.Tracingitshistoricalbackground,theauthorsproposedinthispaperthatthedevelopmentofthisseismoscopestartedaround128A.D.,andbasedonperceptualknowledge,twoideasaboutearthquakescameintobeing,i.e.,earthquakelocationcouldbejudgedaccordingtotheinstrumentshakingdirection,andtheearthquakeandearthsplitwereessentiallydifferent.Intheinstrumentmanufacture,ZhangHengadvocatedaprincipleof"makingutensilstoimitatecosmos".Bythisprinciple,thefollowingthreeproblemswerereadilysolved:theseismoscopeimitatedtheresponseofthesuspensionsystemtoearthquakes(i.e.naturalseismoscope).Technically,thetriggermechanismofthelatchwasusedforreference,anditrecordedthephysicalevidenceofearthquakeoccurrencebyaningeniouswayofaballdroppingfromadragon’smouth.Thesolutionofthesethreekeyproblemsleadtotheemergenceoftheseismoscopein132A.D.andthesuccessfuldetectionofanearthquakein134A.D.Hisinventiondeepenedhumanity’sknowledgeofnaturallaws,andpromotedthedevelopmentofscienceandtechnologyinthattimeandlater.
简介:In2004,China’sdigitalseismicobservationnetworkprojectbegantodeploy40setsYRY-4four-componentboreholestrainmetersinordertomonitorearthquakepreparationprocess.Thepaperdescribesobservedsolidtidalstraindiscretenessandtidalfactoranisotropy,analyzesthereliabilityofobservationaldataanddiscussesthecauseforthisphenomenon.Aftergettingridofinterferences,thenetwork,intwoyearspractice,hasobservedseveralpre-seismicstrainanomaliesatstationsclosetoepicentersespeciallyintheWenchuanMS8.0megaquake.Itshowsthatthisboreholestrainmeternetworkiscapableofmonitoringseismogenicprocess.
简介:ThestudiesonthestructureandphysicalpropertiesoftheEarth'sinteriordonebyChinesegeophysicistsfrom1999to2002werereviewedinthispaper.Itincludesseveralresearchareas:thestructureoftheEarth'sinteriorsusingseismictomography,anisotropyoftheuppermantleinChinaanditsadjacentareas,qualityfactorQβforSwaves,subductionzone,mantlediscontinuities,physicalpropertiesofEarth'smaterialsandothers.Thereviewconcernsmainlythecontents,themethodsandtheresultsofthestudies.ItcanbeseenthatnewprogressinthestudyonthestructureandphysicalpropertiesoftheEarth'sinteriorhasbeenmadeinthelast4yearsinChina.Itisshownonthreeaspects:advancementmadeonsomepreexistentareas;pioneeringonsomenewfieldsandnewmethodsadopted.
简介:Thispaperpresentsamodifiedhalf-sine-squaredloadmodelofthejumpingimpulsesforasingleperson.Themodelisbasedonadatabaseof22,921experimentallymeasuredsinglejumpingloadcyclesfrom100testsubjects.Threedimensionalmotioncapturetechnologyinconjunctionwithforceplateswasemployedintheexperimenttorecordjumpingloads.Thevariationrangeandprobabilitydistributionofthecontrollingparametersfortheloadmodelsuchastheimpactfactor,jumpingfrequencyandcontactratio,arediscussedusingtheexperimentaldata.Correlationrelationshipsbetweenthethreeparametersareinvestigated.Thecontactratioandjumpingfrequencyareidentifiedasindependentmodelparameters,andanempiricalfrequency-dependentfunctionisderivedfortheimpactfactor.Thefeasibilityoftheproposedloadmodelisestablishedbycomparingthesimulatedloadcurveswithmeasuredones,andbycomparingtheaccelerationresponsesofasingle-degree-of-freedomsystemtothesimulatedandmeasuredjumpingloads.Theresultsshowthatarealisticindividualjumpingloadcanbegeneratedbytheproposedmethod.Thiscanthenbeusedtoassessthedynamicresponseofassemblystructures.
简介:HistoricaldataregardingZhangHeng'sseismoscopeisnotsingularproof.Actually,thefourearliesthistoricaldocuments,i.e.,ContinuationofHistoriographyofHanDynasty,HistoriographyoftheLaterHan,BookoftheLaterHanandDingRecordallhaverelevantrecordsofitsstructure,size,principle,responsetoearthquakeandactualapplications.Thesefiveaspectsaresupportedbyarchaeologicalresearch,unearthedculturalrelics,historicalearthquakesandmodernseismologicalstudy.Thesehistoricalmaterialscontainagreatdealofspecificinformationaboutthisancientseismoscope.Inconclusion,theauthenticityandreliabilityofZhangHeng'sseismoscopeareverified.
简介:ResearchonnonlinearR/SmethodanditspplicationinearthquakepredictionBi-QuanWANG(王碧泉);Han-MingHUANG(黄汉明);Hong-ShunFAN(范洪顺);Chuen...
简介:EstimatedGreen'sfunction(EGF)betweenstationshasbeenextractedfromambientseismicnoise,directsurfacewaveandcodawaves.Itisalsoconfirmedbylaboratoryexperimentsonultrasonicsandtheoreticalderivationsassumingdiffusivewavefield,equi-partitionofmodesorrandomsourcesonanenclosedsurface.Thismethodprovidesanewapproachtostudythecrustandmantlestructureatregionalscale,continentalscaleandglobalscale.Followingtheachievementswithseismometerrecords,therecordsofinfrasonicstation,hydrophoneandmicrophonewerealsousedtoobtaintheEGFsofdifferentwavefields.Sincesuperconductinggravimeterisabetterlongperiodinstrumentthanregularseismometer,EGFatlongerperiodisexpectedtobeobtainedwiththecrosscorrelationofgravitydata.Inthispaper,wewillshowtheEGFsextractedbycross-correlationsbetweenthesuperconductinggravimetersandtheseismometers.Boththetraveltimesanddispersioncurvesobtainedfromdifferentdatatypesareconsistent.Theresultshowsthatitispossibletoretrievethedeepstructurebythecrosscorrelationofgravitydata.
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简介:AstatisticalanalysisoftectonicenvironmentforM≥6.0strongearthquakesinChina'scontinentsincethebeginningofrecordedhistoryisperformedbasedonthedataofactivefaultsstudiedduringlast10yearsandresultofcompilationofthefourthversionoftheMapofSeismicRegionalizationofChinaforEarthquakeProtection.Tectonictypesofseismicsourcesofstrongearthquakesinallseismicregionsandthemovementmodesofseismogenicstructuresarediscussed.Meanwhile,ananalysisoflengthsofsurfacerupturezonesproducedbyalltypesofearthquakes,orientationsoflongaxesofmeizoseismalareas,regionaltectonicstressfieldsinseismicsourceregionsforstrongearthquakes,geophysicalfields(gravityanomaly,highconductivitylayeranomaly,andterrestrialheatflowdensity),andrecentverticalcrustaldeformationfieldshavebeencarriedout.
简介:Basedonisotropiclinearporoelastictheoryandundertheundrainedcondition,wesummarizethreeequationsconnectingtheSkempton’scoefficientBwiththegroundwaterlevel.Afteranalysis,weproposeamethodtocalculatetheSkempton’scoefficientBaccordingtotherelationshipbetweenwaterlevelandtidalstrain.WiththismethodwecangetthevalueofBwithouttheearthquakeoccurrence,whichcanprovidethehighfrequencywavesforresearch.Besides,wecanalsogetthein-suitSkempton’scoefficientBwithouttheexperimentofrockphysics.Inaddition,weanalyzetheobserveddataofChangpingstationrecordedingroundwatermonitoringnetwork(abv.,GMN)beforeandaftertheWenchuanMS8.0withthismethod,andfindoutthere’saslightchangeofthevalueofBaftertheseismicwavespassedby,whichimpliesthatthepropagationofseismicwavesmayhavebroughtsomevariationstotheporoelasticmediumofthewell.
简介:AsourceextentanalysisoftheLancangearthquake(Ms=7.6)of1988SI-HUAZHENG(郑斯华)JIANYANG(杨健)CenterforAnalysisandprediction,ChinaSeis...
简介:BasedonSwaverecordsofdeepteleseismsonDigitalSeismicNetworkofShanxiProvince,shearwavevelocitystructuresbeneath6stationswereobtainedbymeansofSwavewaveformfitting.Theresultshowsthatthecrustisthickinthestudiedregion,reaching40kminthicknessunder4stations.Thecrustallalternativeshighvelocitylayerwithlowvelocityone.Thereappearvariedvelocitystructuresfordifferentstations,andthestationsaroundthesametectonicregionexhibitsimilarstructurecharacteristics.Combinedwithdominantdepthdistributionofmanysmall-moderateearthquakes,thecorrelationbetweenseismogeniclayersandcrustalstructuresofhighandlowvelocitylayershasbeendiscussed.
简介:Inthisarticle,weanalyzethecharactersofSV-componentreceiverfunctionofteleseismicbodywavesanditsadvantagesinmappingtheS-wavevelocitystructureofcrustindetail.Similartoradialreceiverfunction,SV-componentreceiverfunctioncanbeobtainedbydirectlydeconvolvingtheP-componentfromtheSV-componentofteleseismicrecordings.OuranalysesindicatethatthechangeofamplitudeofSV-componentreceiverfunctionagainstthechangeofepicentraldistanceislessthanthatofradialreceiverfunction.Moreover,thewaveformofSV-componentreceiverfunctionissimplerthantheradialreceiverfunctionandgivesprominencetothePSconvertedphasesthatarethemostsensitivetotheshearwavevelocitystructureintheinversion.ThesynthetictestsshowthattheconvergenceofSV-componentreceiverfunctioninversionisfasterthanthatoftheradialreceiverfunctioninversion.Asanexample,weinvestigatetheS-wavevelocitystructurebeneathHIAstationbyusingtheSV-componentreceiverfunctioninversionmethod.