简介:IllustrationAllthedatainthiscatalogarechosenfromthe(PreliminarySeismologicalReportofChineseSeismicStations((Itsabbreviationis(MonthlyReport().ThecatalogincludestheeventsofM(4.7inandnearChinaandM(6allovertheworld.The(MonthlyReport(ismonthlycompiledbytheNinthSectionofInstituteofGeophysics,CSB.Theorigintimesofearthquakesinthecatalogadoptcoordinateduniversaltime(UTC)inaccordancewithinternationalconvention.Thelocationofeveryepicenterisexpressedbyitslatitudeandlongitude,atthesametimebythecorrespondinggeographicalregionproposedbyFlinnandEngdahl.Theregionalnamesareonlyforreferencesanddonotimplyanypoliticalsignificance.Thenumberofstationsusedandstandarddeviationarealsogiveninordertoillustratetheprecisionoflocation.
简介:Morethanahalfofstrongearthquakesintheworldarelocatedinshallowdepthatthesubductingplateboundaryinsqueezedzones.Owingtothedifferenceinspeedbetweenthemovingseaplates,thestrainenergyisaccumulatedandreleasedcyclicallyinsqueezedzones.Severalmethodsweredevelopedtoanalyzethemedium-andshort-termpotentialofmainshocks.Thesemethodscanbeclassifiedinto(1)lessdatasystemsusingthetheoryofgreymodelforearthquakeprediction,(2)quasi-periodicsystemsusingearthquakeactivityanalysis,(3)systemsofgroupedactivityusingorderanalysis,and(4)nonlinearsystemsusingbackpropagation(BP)ofneuralnetworkforpredictionanalysis.Basedupontheseanalyticmethods,riskmapsforthepredictionofstrongearthquakescanbedrawnusingtherecordsofstrongearthquakesinTaiwanforthepast100years.Theseriskmapsinclude(1)aseismicriskmap,(2)alossriskmap,(3)ahazarddegreemap,and(4)alossdegreemap.Theseriskmapsmakeitpossibletodoamedium-termpredictionofmainshocksonthe10-yearscale.
简介:TheSimplifiedSimpleBiospheremodel(SSiB)isvalidatedinoff-linesimulationsagainstfieldmeasurementsinthesummerof2001fromtheChinaHeavyRainfallExperimentandStudy(CHeRES)overagrasslandsitelocatedinthelowerreachesoftheYangtzeRiver.Wheninitializedanddrivenbytheobservedatmosphericforcing,themodelreproducedtheobservedsurfaceheatfluxesandsurfaceskintemperaturerealistically.Themodelwasalsoabletowellsimulatethevariationofsoilwatercontent.Thesensitivityexperimentsfoundthattheleafreflectancewasthemostsignificantparameterinimprovingtheestimationofsurfacealbedoduringbothwetanddryperiods.Thisstudysuggeststhatthemodeliscapableofsimulatingthephysicalprocessesandofassessingtheimpactofbiophysicalparametersthatrelatetoland-atmosphereinteractionsovertheeasternAsianmonsoonregions,whichiscrucialformesoscaleatmosphericmodels.
简介:OnOctober27,2001,alargeearthquakewithMs6.0,namedtheYongshengearthquake,occurredalongtheJinshajiangsegmentofChenghaifaultinYongshengCounty,YunnanProvince.ItisthelargesteventtooccuralongtheChenghaifaultinthelast200years.Theseismo-geologicalsurveyshowsthattheseismogenicfault,whichistheJinshajiangsegmentofChenghalfault,takesleft-lateralstrike-slipasitsdominantmovementpattern.Accordingtodifferencesinverticalmotion,motiontime,landformsandscales,theChenhalfaultcanbedividedintoeightsegments.TheJinshajiangsegmenthasaverticaldislocationrateof0.4mm/a,farlowerthanthemeanrateoftheChenghaifault,about2.0mm/a.It'sdeducedthatthetwosidesofJinshajiangsegment'stuck'tightlyandhinderedthestrike-slipoftheChenghaifault.ThestrongearthquakedistributionbeforethiseventshowsthattheJinshajiangsegmentwasintheseismicgap.TheChenghaifault,asaboundaryoftectonicsub-blocks,makestheNorthwestYunnanblockandtheMiddleYunnanblockmoveclockwise,andtheirmarginsmoveoppositelyalongtheChenghalfault.InthemotionprocessoftheChenghaifault,structuralhindranceandtheseismicgapofstrongearthquakesarepropitioustotheconcentrationandaccumulationofstructurestress.Asaresult,theYongshengMs6.0earthquakeoccurred.TheSujiazhuang-ShangangfusegmentissimilartotheJinshajiangsegmentwithalowverticalmotionrateof0.3mm/aandintheseismicgap.Soit'spostulatedthatthesegmentmaybecomeanewstructurehindrance,andtheYongshengMs6.0earthquakemaytriggertheoccurrenceoffuturelargeearthquakesalongthissegment.
简介:21世纪的第一个十年,陨石学与天体化学研究在中国迎来了一个前所未有的发展时期。在南极格罗夫山地区共开展了5次科学考察,收集到超过1万块陨石,提供了珍贵的研究样品;嫦娥工程的立项和一期工程的成功实施,是陨石学与天体化学发展的重大机遇,也是挑战;高精度原位微区分析平台建设的完成,则为地外物质样品的分析提供了关键的技术保证。更为重要的是,通过大量南极陨石的分类工作,培养和锻炼了陨石学研究的青年人才。在此基础上,通过对各化学群陨石的研究,取得了许多重要的成果,包括陨石中前太阳颗粒的发现和研究、陨石中的灭绝核素、太阳星云在不同条件下的凝聚过程、月球陨石和火星陨石的岩石学成因与同位素定年、陨石的冲击变质与高压矿物、以及中国第一个陨石坑的证实等。
简介:Inthispaperchangesinfocalmechanisms,parametersofwavespectra,andstressdropsfortheMS=5.0foreshockandMS=6.0mainshockinFebruary2001inYajiangCounty,Sichuan,andseismicityinepicentralregionarestudied.ComparisonoffocalmechanismsfortheYajiangearthquakeswithdistributionpatternsofaftershocks,thenodalplaneI,strikinginthedirectionofNEN,oftheYajiangM=5.0eventischosenasthefaultingplane;thenodalplaneII,strikinginthedirectionofWNW,oftheM=6.0eventasthefaultingplane.Thestrikesofthetwofaultingplanesarenearlyperpendiculartoeachother.ThelevelofstressdropsintheepicentralregionbeforetheoccurrenceoftheM=6.0earthquakeincreases,whichisconsistentwithincreaseofseismicityintheepicentralregion.TheratedecayoftheYajiangearthquakesequence,changesinwavespectraforforeshocksandaftershocks,andfocalmechanismsarecomplex.
简介:NewObservationsonphosphatizedSpheroidalFossilsinSinianDoushantuoanPhosphoritesinWeng'an,GuizhouProvinceInrecentyearsmuchattentionhasbeenpaidtophosphatizedspheroidalfossilsfoundintheSinianDoushantuoanphosphoritesinweng'an,GuizhouProvince.Disputeshavebeenlongexistedabouttheirphylogeneticaffinity.Basedonsomenewdiscoveriesandthepresentknowledge,someresearchersinterpretsomeofthephosphatizedspheroidalfossilsasanimalembryos,whereasothersholodtheutterlyidifferentviewthattheypaper,basedonnewdataofsomespheriodalfossilsindiscussedandreinterpreted.Itisobviousthatthephosphatizedspheroidalfossilassemblagefoundinweng'anconsistsofcyanobacteria,benthicmelticellularalgae,planktonicacritarchsandotherfossilswithuncertainassignments,andprovideanexceptionallywell-preservedphosphatizedLagerstatten.
简介:TheYajiangearthquakesequencein2001,withthemajoreventsofMs5.1onFeb.14andofMs6.0onFeb.23,aresignificanteventsintheSichuanregionduringthelast13years.Eighty-eightearthquakesinthesequencewithatleast5distinctonsetparametersforeachrecordedbytheSichuanSeismicNetworkintheperiodofJan.1throughJune30,2001werechosenforthisstudy.TheeventsarerelocatedandthefocalmechanismisderivedfromP-waveonsetsfor13eventswithrelativelylargermagnitudes.Thefocaldepthofallearthquakesfallbetweenarangeof2kmto16km,withdominantdistributionbetween9kmto11km.Theforeshocks,theMs5.1earthquakeandtheMs6.0earthquakeandtheiraftershocksarealllocatedclosetotheZihefaultandthedominantepicentraldistributionisinNWdirection,identicaltothatofthefault.ThefracturesurfaceofthefocalmechanismisdeterminedinaccordancetothemasstransferorientationintherecentearthdeformationfieldintheYajiangregion.ThePaxesoftheprincipalcompressivestressinfocalmechanismsolutionsofthe13eventsshowbiggerverticalcomponents,andthehorizontalprojectiontrendingSE.Theearthquakesareofleft-lateral,strike-slipnormal,andnormalstrike-sliptypes.TherupturesurfaceofmostearthquakesstrikeNW-SE,dippingSW.Basedontheaboveinformation,weconcludethattheZihefaultthatcrossestheearthquakearea,strikingNWanddippingSW,istheseismogenicfaultfortheYajiangearthquakesequence.
简介:Usingthe78focalmechanismsolutionsoftheforeshocks,mainshockandaftershocksoftheearthquakesequencefortheYao'anearthquake,thecharacteristicsofthefocalfaultsandstressfieldfortheearthquakesequenceareanalyzed.TheresultsshowthatthemainruptureplaneoftheYao'anearthquakesequenceisatectonicfaultwithN50°Wstrikeandsteepdipandallthemainshock,theforeshocksandthevastmajorityofaftershocksoccurredonthemainruptureplane.AtectonicfracturewithNNE-NEstrikealsoparticipatedindevelopmentprocessofthesequencedominatedbyprincipalcompressionalstresswithnearlyhorizontalorientationSSEisconsistentwiththeregionaltectonicstressfield.Inthesequencedevelopment,thestressfieldinthefocalregionwascomplexwithmultiaximuthsandmulti-actionmodelsandthefocalruptureshowedcomplexfeatureswithmulti-directionsandmulti-patterns.
简介:TheinvestigationondamagestofrozensoilsitesduringtheWestKunlunMountainsPassearthquakewithMs8.1in2001showsthatthefrozensoilintheseismicareaiscomposedmainlyofmoraine,alluvialdeposit,diluvialdepositandlacustrinedepositwiththedepthvaryinggreatlyalongtheearthquakerupturezone.Thedeformationandruptureoffrozensoilsitesaremainlyintheformofcoseismicfracturezonescausedbytectonicmotionandfissures,liquefaction,seismicsubsidenceandcollapseresultingfromgroundmotion.Theearthquakefracturezonesonthesurfacearemainbrittledeformations,which,undertheeffectofsinistralstrike-slipmovement,arerepresentedbyshearfissures,tensionalcracksandcompressivebulges.Thedistributionandconfigurationpatternsofdeformationandrupturesuchasfissures,liquefaction,seismicsubsidenceandlandslidesareallrelatedtotheambientrockandsoilconditionsoftheearthquakearea.Thedistributionofearthquakedamageischaracterizedbylarge-scalerupturezones,rapidintensityattenuationalongtheQinghai-Xizang(Tibet)Highway,wherebuildingsdistributeandpredominanteffectofrockandsoilconditions.