东北地区660km间断面附近波速结构研究-豆柴文库

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东北地区660km间断面附近波速结构研究
Title:StudyonVelocityStructurenearthe660kmDiscontinuityinNortheastChina
Abstract:
The660kmdiscontinuity,whichisfoundintheuppermostmantle,isanimportantinterfacewithintheEarth'sinterior.Understandingthevelocitystructurenearthisdiscontinuitycanprovidevaluableinsightsintothethermal,chemical,anddynamicprocessesoccurringinthedeepmantle.Inthisstudy,weaimtoinvestigatethevelocitystructurenearthe660kmdiscontinuityinthenortheasternregionofChina.Weanalyzedseismicdataandconductedwaveformmodelingtoconstraintheseismicvelocitiesandvariationsatthisdepth.Ourresultsrevealimportantfindingsregardingthenatureandpropertiesofthe660kmdiscontinuityinthisparticularregion.
1.Introduction
The660kmdiscontinuity,alsoknownasthemantletransitionzone,isaseismicboundaryoccurringatadepthofapproximately660kilometersbelowtheEarth'ssurface.Itseparatestheupperandlowermantleandisassociatedwithsignificantchangesinmaterialpropertiesandphasetransformations.Thestudyofthe660kmdiscontinuityiscrucialforbetterunderstandingthebehavioroftheEarth'sdeepinterior,includingmantledynamics,mantleconvection,andmantlecomposition.Inthisstudy,wefocusonthenortheasternregionofChinatoexplorethevelocitystructurenearthisimportantboundary.
2.Methodology
Toinvestigatethevelocitystructurenearthe660kmdiscontinuity,wecollectedseismicdatafromvariousstationsinthenortheasternregionofChina.Weselectedhigh-qualityearthquakeeventswithamagnitudegreaterthan6.0andadepthrangenearthediscontinuity.Theseismicwaveformswereprocessedtoobtainaccuratetraveltimeinformation.Wethenperformedwaveformmodelingusingsyntheticseismogramsandvariousvelocitymodelstodeterminethebest-fitvelocitystructureatthe660kmdepth.
3.Results
Ouranalysisrevealssignificantvariationsinseismicvelocitiesnearthe660kmdiscontinuityinthestudiedregion.Weobservedadistinctincreaseinvelocitiesabovethediscontinuity,followedbyasuddendecreaseinvelocitieswithinthetransitionzone.Theseobservationssuggestthepresenceofalow-velocityzoneatthetopofthelowermantle.Additionally,wedetected