简介:AfterthereleaseofthepreviousreporttotheCommitteeonSpaceResearch(COSPAR)onprogressachievedbyChinesescientistsinionosphericresearches(LiuLBandWanWX,2016),intherecenttwoyears(2016–2017)manyinterestingnewinvestigationsintovariousionosphericrelatedissueshavebeencompleted.Inthisreport,about100publicationsaresummarized.Thetopicshighlightedareasfollows:Ionosphericspaceweather,ionosphericdynamics,ionosphericclimatologyandmodelling,ionosphericirregularityandscintillation,GlobalNavigationSatelliteSystem(GNSS)relatedionosphericissuesandothertechniques,andradiowavepropagationintheionosphere.AnoutstandingfeatureisthatmoreandmoreobservationsfromtheMeridionalProjectsupportedtheionosphericinvestigations.
简介:At12:07UT(8:07pmChinaStandardTime)on2017Oct4,abrightbolidewaswidelyobservedintheShangri-LaregionoftheProvinceofYunnan,China(Figure1).TheeventwaswellobservedbythegeneralpublicasittookplaceonthenightoftheMidAutumnFestival,whichisassociatedwithmoongazing.SonicboomsandgroundshakingwerereportedinanareaofaboutathousandsquarekilometersnorthwestofShangri-LaCity.DatafromU.S.governmentsensorssuggeststhattheimpactenergyoftheeventwasapproximately0.54ktTNTequivalent,withtheterminusofthebolidepositionedat28.1°N,99.4°E.ThisisthelargestobservedbolideeventoverlandsincethebolideeventthattookplaceinMauritaniaon2016Jun27(1.2kt).
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简介:At06:34(CST)onNov.18,2017,anM6.9earthquakeoccurredintheMainlingCounty,NyingchiRegionofXizangAutonomousRegion,China.Theepicenterislocatedat95.02°E,29.75°Nandthefocaldepthisabout10km(Figure1).Theepicenterisabout100kmfromtheMainlingCounty.Theaverageelevationwithin5kmisabout3100m.Thisearthquakehascausedwidespreadconcernamongmembersofgovernment,researchinstitutions,andpublicmedia.
简介:OnAug.8,2017,anMS7.0earthquakestruckJiuzhaigou,acountyofSichuanprovince,China.Anumberofinvestigationsandstudieshavebeenconducted,someofwhichinvolvedlocalvelocitymodels.However,thesuitabilityofthesemodelshasnotbeenproperlyaddressed.Herewecollect11already-existingmodels,includingthoseusedinstudiesofthe2017MS7.0Jiuzhaigouearthquake,choose10localstationssurroundingtheearthquake,andemploythesametechnique(TRIT)torelocatethehypocenter.Andfurthermore,wechooseamoresuitablemodelfromthe11already-existedmodelsbyanalyzingtherelocationprocessandtherelocatedresultsforreasonability.Finally,ourconclusionisthatthemodelFang2018ismoresuitableandthehypocenterparameters,103.801°E,33.192°Nand15.8kmforlongitude,latitudeanddepth,respectively,and2017-08-0813:19:46.66foritsorigintime,basedonthismodelshouldberecommendedforthe2017MS7.0Jiuzhaigouearthquake.
简介:The13November2016KaikouraearthquakeoccurredinthenortheasterncoastalregionoftheSouthIsland,NewZealand.TheMw7.8mainshockgeneratedacomplexpatternofsurfaceruptures,andwasfollowedwithinabout12hoursbythreemoderateshocksofMw≥6.0.HereweuseteleseismicwaveformstoinvertforthesourceruptureoftheKaikouraearthquake.Theresultingslip-distributionmodelexhibitsinsignificantslipnearthehypocenterandthreepocketsofmajorslipzoneswithdistinctsensesofmotion.Themainshockstartedfromarupturenearthehypocenter,grewintothrustonshallowcrustalfaults~50kmnortheastofthehypocenter,andthendevelopedintotwoslipzones:adeeperonewithobliquethrustandashalloweronewithalmostpurelyright-lateralstrike-slip.Locationsofthethrustandstrike-slipmotionsintheslip-distributionmodelagreewellwithreportedcoastalupliftsandhorizontaloffsets.Theoverallslippatternisdominatedbyhorizontalmotion,especiallyatshallowdepth,duetothepartitioningofthrustandstrike-slipmotionsabovethesubductionzonemegathrust.Aftershockdistributionsuggeststhatmostaftershockstendtooccurneartheedgesofthemajorslipzonesofthemainshock.Thisobservationonaftershocklocationsmayprovideusefulinformationforseismichazardassessmentsafterlargeearthquakes.
简介:OnNovember13,2016,anMW7.8earthquakestruckKaikourainSouthIslandofNewZealand.Bymeansofback-projectionofarrayrecordings,ASTFs-analysisofglobalseismicrecordings,andjointinversionofglobalseismicdataandco-seismicInSARdata,weinvestigatedcomplexityoftheearthquakesource.Theresultshowsthatthe2016MW7.8Kaikouraearthquakerupturedabout100sunilaterallyfromsouthtonortheast(~N28°–33°E),producingaruptureareaabout160kmlongandabout50kmwideandreleasingscalarmoment1.01×1021Nm.Inparticular,theruptureareaconsistedoftwoslipasperities,withoneclosetotheinitialrupturepointhavingamaximalslipvalue~6.9mwhiletheotherfarawayinthenortheasthavingamaximalslipvalue~9.3m.Thefirstasperityslippedforabout65sandthesecondonestarted40safterthefirstonehadinitiated.Thetwoslippedsimultaneouslyforabout25s.Furthermore,thefirsthadanearlythrustslipwhilethesecondhadboththrustandstrikeslip.Itisinterestingthattherupturevelocitywasnotconstant,andthewholeprocessmaybedividedinto5stagesinwhichthevelocitieswereestimatedtobe1.4km/s,0km/s,2.1km/s,0km/sand1.1km/s,respectively.Thehigh-frequencysourcesdistributednearlyalongtheloweredgeoftherupturearea,thehighfrequencyradiatingmainlyoccurredatlaunchingoftheasperities,anditseemedthatnohigh-frequencyenergywasradiatedwhentherupturingwasgoingtostop.
简介:AtUTC2017-11-1218:18:17,anMw7.3earthquakeoccurredattheborderbetweenIranandIraq(location34.886°N,45.941°E,depth23kmaccordingtoUSGS).WecarriedoutfocalmechanismandruptureprocessstudieswiththedatafromIRISdatacenter,using26far-fieldP-waveformsand25SH-waveformswithhighS/Nratioandrelativelyevenazimuthcoverage(epicentraldistance)inapointsourcemodeltoinvertforthefocalmechanismsolution;theresult(Figure1)wasusedtoconstructafinitefaultmodelforruptureprocessinversion(YaoandJi,1997;Wangetal.,2008),resultinginapreliminaryslipdistributionofthisearthquake(Figures2-4).Thecalculatedseismicmomentis1.1×1020N·m,Mw=7.3.Themaximumslipisabout700cm.
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简介:Amapoftheaverageatomicnumberoflunarrockandsoilcanbeusedtodifferentiatelithologyandsoiltypeonthelunarsurface.Thispaperestablishesalinearrelationshipbetweentheaverageatomicnumberoflunarrockorsoilandthefluxofpositionannihilationradiation(0.512-MeVgamma-ray)fromthelunarsurface.TherelationshipisconfirmedbyMonteCarlosimulationwithdatafromlunarrockorsoilsamplescollectedbyLuna(Russia)andApollo(USA)missions.AmapoftheaverageatomicnumberofthelunarrockandsoilonthelunarsurfacehasbeenderivedfromtheGamma-RaySpectrometerdatacollectedbyChang’e-1,anunmannedChineselunar-orbitingspacecraft.Inthemap,thehigheraverageatomicnumbers(ZA>12.5),whicharerelatedtodifferenttypesofbasalt,areinthemariaregion;thehighestZA(13.2)readingsareassociatedwithSinusAestuum.ThemiddleZA(~12.1)regions,intheshapeofirregularovalrings,areinWestOceanusProcellarumandMareFrigoris,whichseemstobeconsistentwiththedistributionofpotassium,rareearthelements,andphosphorusasauniquefeatureonthelunarsurface.Theloweraverageatomicnumbers(ZA<11.5)arefoundtobecorrelatedwiththeanorthositeonthefarsideoftheMoon.