简介：ThispaperisrelatedtostudyoftheiondensityrecordedbythelowaltitudesatelliteDEMETER.Itwillpresentionosphericperturbationsobservedduringlargeseismicevents.Astheionosphereishighlyvariable,thepaperwillshowastatisticalanalysisperformedontheplasmaparametersduringnighttime.Analgorithmhasbeenimplementedtodetectcrestsandtroughsinthedatabeforeworld-wideearthquakes.Theearthquakeshavebeenclassifieddependingontheirmagnitude,depth,andlocation(land,belowthesea,closetoacoast).Duetotheorbit,DEMETERreturnsabovethesameareaeveryday(onceduringdaytime,onceduringnighttime)butnotatthesamedistanceofagivenepicenter.Then,foreachearthquake,datahavebeencheckeduntil15daysbeforetheshockwhenthedistancebetweenthetraceoftheorbitandtheepicenterislessthan1500km.Theresultsofthestatisticalanalysisarepresentedasfunctionsofvariousparameters.Acomparisonisdonewithtwootherdatabaseswhere,ononehand,thelocationoftheepicentershasbeenrandomlymodified,andontheotherhand,thelongitudeoftheepicentershasbeenshifted.Resultsshowthatthenumberandtheintensityoftheionosphericperturbationsarelargerpriortoearthquakesthanpriortorandomevents,andthattheperturbationsincreasewiththemagnitude.

简介：Basedonthecasestudiesandstatisticalanalysisofearthquake-relatedionosphericdisturbancesmainlyfromDEMETERsatellite,ground-basedGPSandionosoundingdata,thispapersummarizesthestatisticalcharacteristicsofearthquake-relatedionosphericdisturbances,includingelectromagneticemissions,plasmaperturbationsandvariationofenergeticparticleflux.AccordingtothemainresultsdonebyChinesescientists,fusingwiththeexistedstudyfromglobalresearches,seismo-ionosphericdisturbancesusuallyoccurredafewdaysorhoursbeforeearthquakeoccurrence.Parallelingtothesecasestudies,lithosphere-atmosphere-ionosphere(LAI)couplingmechanismsarecheckedandoptimized.Athermo-electricmodelwasproposedtoexplaintheseismo-electromagneticeffectsbeforeearthquakes.Apropagationmodelwasputforwardtoexplaintheelectromagneticwavesintotheionosphere.Accordingtotherequirementofearthquakepredictionresearch,Chinaseismo-electromagneticsatellite,thefirstspace-basedplatformofChineseearthquakestereoscopicobservationsystem,isproposedandplannedtolaunchatabouttheendof2014.ItfocusesoncheckingtheLAImodelanddistinguishingearthquake-relatedionosphericdisturbance.ThepreliminarydesignforthesatellitewilladoptCAST-2000platformwitheightpayloadsonboard.Itisbelievedthatthesatellitewillworktogetherwiththegroundmonitoringnetworktoimprovethecapabilitytocaptureseismo-electromagneticinformation,whichisbeneficialforearthquakemonitoringandpredictionresearches.

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