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:Inthispaper,basedonGansuDigitalSeismicNetworkdatasince1990,wecalculatedb-valueand⊿b-valueoftheneighborhoodareabeforethe2013Minxian-ZhangxianM_S6.6,earthquake.Theresultsshowthattheearthquakeoccurredatthemarginofthesignificantlylowerb-valueareainsoutheastofGansuandbeforetheearthquaketheneighborhoodareahadanobviouslyabnormal⊿b-value.Fromtheearthquakeandthespatialdistributionoflowb-value,theregionstillhasthepossibilityofgeneratingdangerousstrongearthquakes.
简介:AnalysisoffutureseismicityofJing-Jin-Tangregionandsevenmajorseismiczones withtheextreme-valuetheoryRanZHOU(周冉)andBang-HutLIN(...
简介:Micro-aftershockswithmagnituderangeof1.5-4aroundtheWenchuanearthquakeepicenter,thesouthernpartoftheLongmenshanfaultzone,exhibitgoodfrequency-magnitudelinearrelationships,thusenablingb-valueanalysis.Theaverageb-valueformicro-aftershocksofM1.5-4fromJulytoDecemberof2008inourlocalstudyregionisabout0.88,similartotheb-valueforallaftershocksofM3.0-5.5fromMay,2008toMay,2009alongthewholeLongmenshanfaultzone.Thesimilaritybetweenthelocalandregionalb-valuespossiblyindicatesthatthesouthernpartoftheLongmenshanfaultzonehassimilarseismogenicenvironmenttothewholeLongmenshanfaultzone.Alternatively,itmayalsoimplythatb-valuesderivedfromalleventswithoutconsiderationofstructuralvariationcannotdiscriminatelocal-scaletectonicinformation.Thepresentstudyshowsthattheb-valuefortheWenchuanearthquakemicro-aftershocksvarieswithdifferentregions.Theb-valueinsouthwestoftheYingxiutownishigherthanthatinthenortheastoftheYingxiutown.Thehighb-valueinthesouthwestpartwheretheWenchuanearthquakemainshockhypocenterlocatedindicatesthatthecurrentstressaroundthehypocenterregionismuchlowerthanitssurroundingarea.Theb-valuesarealsodependentondepth.Atshallowdepthsof<5km,theb-valuesareverysmall(~0.4),possiblybeingrelatedtostrongwaveattenuationorstrongheterogeneityinshallowlayerswithhighcontentofporosityandfractures.Atdepthsof~5-11km,wheremostaftershocksconcentrated,theb-valuesbecomeashighas~0.9-1.0.Atthedepthbelow~11km,theb-valuesdecreasewiththedepthincreasing,beingconsistentwithincreasingtectonichomogeneityandincreasingstresswithdepth.