学科分类
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43 个结果
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  • 简介:IllustrationAllthedatainthiscatalogarechosenfromthe(PreliminarySeismologicalReportofChineseSeismicStations((Itsabbreviationis(MonthlyReport().ThecatalogincludestheeventsofM(4.7inandnearChinaandM(6allovertheworld.The(MonthlyReport(ismonthlycompiledbytheNinthSectionofInstituteofGeophysics,CSB.Theorigintimesofearthquakesinthecatalogadoptcoordinateduniversaltime(UTC)inaccordancewithinternationalconvention.Thelocationofeveryepicenterisexpressedbyitslatitudeandlongitude,atthesametimebythecorrespondinggeographicalregionproposedbyFlinnandEngdahl.Theregionalnamesareonlyforreferencesanddonotimplyanypoliticalsignificance.Thenumberofstationsusedandstandarddeviationarealsogiveninordertoillustratetheprecisionoflocation.

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  • 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.

  • 标签: Earthquake prediction Medium-and SHORT-TERM Main shock
  • 简介:TheSimplifiedSimpleBiospheremodel(SSiB)isvalidatedinoff-linesimulationsagainstfieldmeasurementsinthesummerof2001fromtheChinaHeavyRainfallExperimentandStudy(CHeRES)overagrasslandsitelocatedinthelowerreachesoftheYangtzeRiver.Wheninitializedanddrivenbytheobservedatmosphericforcing,themodelreproducedtheobservedsurfaceheatfluxesandsurfaceskintemperaturerealistically.Themodelwasalsoabletowellsimulatethevariationofsoilwatercontent.Thesensitivityexperimentsfoundthattheleafreflectancewasthemostsignificantparameterinimprovingtheestimationofsurfacealbedoduringbothwetanddryperiods.Thisstudysuggeststhatthemodeliscapableofsimulatingthephysicalprocessesandofassessingtheimpactofbiophysicalparametersthatrelatetoland-atmosphereinteractionsovertheeasternAsianmonsoonregions,whichiscrucialformesoscaleatmosphericmodels.

  • 标签: 离线统计 亚洲季风型气候地区 中尺度大气模型 CHeRES 降雨量
  • 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.

  • 标签: 震源 地震事件 金沙江 云南
  • 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。

  • 标签: 陨石 太阳系外物质 灭绝核素 太阳星云 小行星撞击
  • 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.

  • 标签: 地震 序列特征 源参数 前震 余震 中国
  • 简介:NewObservationsonphosphatizedSpheroidalFossilsinSinianDoushantuoanPhosphoritesinWeng'an,GuizhouProvinceInrecentyearsmuchattentionhasbeenpaidtophosphatizedspheroidalfossilsfoundintheSinianDoushantuoanphosphoritesinweng'an,GuizhouProvince.Disputeshavebeenlongexistedabouttheirphylogeneticaffinity.Basedonsomenewdiscoveriesandthepresentknowledge,someresearchersinterpretsomeofthephosphatizedspheroidalfossilsasanimalembryos,whereasothersholodtheutterlyidifferentviewthattheypaper,basedonnewdataofsomespheriodalfossilsindiscussedandreinterpreted.Itisobviousthatthephosphatizedspheroidalfossilassemblagefoundinweng'anconsistsofcyanobacteria,benthicmelticellularalgae,planktonicacritarchsandotherfossilswithuncertainassignments,andprovideanexceptionallywell-preservedphosphatizedLagerstatten.

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  • 简介:1气候概况今年秋季全区气温偏高,降水中西部地区偏多,东部区偏少;初霜冻中西部地区偏晚,东部大部地区偏早,全区未出现严重霜冻灾害,日照充足,秋末局部地区出现降雪、降温天气,大风偏少.

  • 标签: 2001年 秋季 气候影响评价 气温 降水 农业
  • 简介:2001年6月11~13日,三明市出现了一场连续性暴雨到大暴雨天气过程,强降水集中在我市的西北部,建宁、将乐、宁化、清流、明溪等县出现了暴雨或大暴雨,大暴雨中心在清流,6月13日雨量达195.9毫米,宁化次之,该日雨量为154.9毫米(见表1)。这次连续性暴雨过程的特点是:持续时间长、强度大、灾情重。

  • 标签: 大暴雨 三明市 成因分析 连续性暴雨 暴雨天气过程 暴雨中心
  • 简介:利用MICAPS系统资料和台站网络系统资料对2001年6月23日宁波地区4个测站出现暴雨和大暴雨过程的环境形势、物理量场、单站要素、卫星云图及多普勒雷达回波图进行了天气学诊断分析,揭示其主要环境条件特征,研究其变化规律,结合多年业务实践,利用相似的气候背景条件和物理量、要素图象特征,试图为大暴雨前0~24小时的预报提供背景依据.

  • 标签: 大暴雨 特征分析 天气过程分析 2001年 6月 MICAPS
  • 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.

  • 标签: 地震强度 破裂特征 焦点压力场 地震层断点 四川
  • 简介:Usingthe78focalmechanismsolutionsoftheforeshocks,mainshockandaftershocksoftheearthquakesequencefortheYao'anearthquake,thecharacteristicsofthefocalfaultsandstressfieldfortheearthquakesequenceareanalyzed.TheresultsshowthatthemainruptureplaneoftheYao'anearthquakesequenceisatectonicfaultwithN50°Wstrikeandsteepdipandallthemainshock,theforeshocksandthevastmajorityofaftershocksoccurredonthemainruptureplane.AtectonicfracturewithNNE-NEstrikealsoparticipatedindevelopmentprocessofthesequencedominatedbyprincipalcompressionalstresswithnearlyhorizontalorientationSSEisconsistentwiththeregionaltectonicstressfield.Inthesequencedevelopment,thestressfieldinthefocalregionwascomplexwithmultiaximuthsandmulti-actionmodelsandthefocalruptureshowedcomplexfeatureswithmulti-directionsandmulti-patterns.

  • 标签: 震源 断层 应力场 姚安地震 2001年 1月
  • 简介:从天气形势、卫星云图、物理量等方面对2001年4月19~20日大暴雨过程进行了分析,总结出这次暴雨的地面和850hPa一些特性.

  • 标签: 大暴雨 形势 分析
  • 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.

  • 标签: 昆仑山垭口 地震 冻土 破坏特震 地表运动