摘要
ThevelocitystructureofthecrustbeneathLiaoningprovinceandtheBohaiseainChinawasimagedusingambientseismicnoiserecordedby73regionalbroadbandstations.Allavailablethree-componenttimeseriesfromthe12-monthspanbetweenJanuaryandDecember2013werecross-correlatedtoyieldempiricalGreen'sfunctionsforRayleighandLovewaves.PhasevelocitydispersioncurvesfortheRayleighwavesandtheLovewavesweremeasuredbyapplyingthefrequencytimeanalysismethod.DispersionmeasurementsoftheRayleighwaveandtheLovewavewerethenutilizedtoconstruct2Dphase-velocitymapsfortheRayleighwaveat8–35speriodsandtheLovewaveat9–32speriods,respectively.BothRayleighandLovephase-velocitymapsshowsignificantlateralvariationsthatarecorrelatedwellwithknowngeologicalfeaturesandtectonicsunitsinthestudyregion.Next,phasedispersioncurvesoftheRayleighwaveandtheLovewaveextractedfromeachcellofthe2DRayleighwaveandLovewavephase-velocitymaps,respectively,wereinvertedsimultaneouslytodeterminethe3Dshearwavevelocitystructures.ThehorizontalshearwavevelocityimagesclearlyandintuitivelyexhibitthattheearthquakeswarmsintheHaichengregionandtheTangshanregionaremainlyclusteredinthetransitionzonebetweenthelow-andhigh-velocityzonesintheuppercrust,coincidingwithfaultzones,andtheirdistributionisverycloselyassociatedwiththesefaults.Theverticalshearwavevelocityimagerevealsthatthelowercrustdownwardtotheuppermostmantleisfeaturedbydistinctlyhighvelocities,withevenahigh-velocitythinnerlayerexistingatthebottomofthelowercrustnearMohoincentralandnortherntheBohaiseaalongtheTanlufault,andthesephenomenacouldbecausedbytheintrusionofmantlematerial,indicatingtheTanlufaultcouldbejustastheuprisingchannelofdeepmaterials.
出版日期
2017年01月11日(中国Betway体育网页登陆平台首次上网日期,不代表论文的发表时间)