简介:前言自autodesk收购alisa之后,Maya软件的命运就蒙上了一层神秘的面纱,一时间预测,谣言不绝于耳,甚至有人认为autodesk会结束Maya而专注发展3dmax。重重疑云直至2006年7月31日方才散尽,因为在这一天,autodesk公司正式发布了Maya软件的最新版——Maya8.0。
简介:ThegreatMs8.0Wenchuanearthquakehasbeenthemostdestructiveearthquakesince1949inChina.TheearthquakeoccurrednomorethanhalfayearaftertheestablishmentoftheNationalStrongMotionObservationNetworkSystem(NSMONS)ofChina;whatismore,theepicenterwaslocatedintheareawithdensestrongmotionobservationstationssothatalargenumberofstrongmotionrecordsofthemainshockwereobtained.Inthispaper,501strongmotionrecordsfrom167observationstationsareutilizedtoestablishthegroundmotionattenuationrelationsinthreedirectionsintherangeoffaultdistancelessthan600km.Theresultshowsthedifferenceofseismicmotionattenuationintwohorizontaldirectionsisinsignificant.Itisthefirsttimethatstrong-motionrecordsareusedtoestablishthegroundmotionattenuationrelationsoftheMS8.0earthquakeinChina.
简介:本文对国家强震动台网中心收集的2008年5月12日14时28分04秒汶川8.0级地震中获取的420组三分量加速度记录进行了处理和初步分析。在这次地震中布设在龙门山断裂带及其周围地区的50多个台站获得了大于100gal的加速度记录,有46组三分量加速度记录的断层距小于100km,使中国大陆近断层区域所获得的强震动加速度记录的数量成倍增加。本文依据这批数据,对汶川大地震强震动特性进行了初步分析,给出了此次地震断层附近地区的PGA衰减规律,并利用此规律模拟了断层附近的加速度峰值,绘制了PGA分布图、竖向PGA与水平向PGA比值图;给出了汶川地震断层附近的加速度反应谱、上盘效应、竖向效应、速度大脉冲效应等地震动特征,这些特征可作为抗震设计规范修订的依据并供灾区重建时参考。
简介:在这份报纸,我们分析外壳的运动,紧张领域变化和大规模在Wenchuan地震前的水平变丑的动态特征(女士=8.0)用从
简介:Inordertostudythespatiotemporalevolutionoftheprecursoryanomalies10yearsbeforetheWenchuanMS8.0earthquakein2008,theepicentraldistanceoftheprecursoryanomaliesiscalculatedbyusingthegeometriccenteroftheruptureregionandtheellipticalcenterlineoftheaftershockregion.Theresultshows,precursoranomaliesgraduallyincreasedabout2yearsbeforetheWenchuanearthquake.Theratioofabnormalitemsisgreaterthan25%inthenearsourcearea(abouttwicethesourcescale)and17%-24%intheremotearea(about3-5timesthesourcescale).Therearethreedifferentstagesofspatiotemporalevolutionofprecursoryanomalies.Duringtheαstage(includingα1andα2,between700to3000daysbeforethemainearthquake),theanomaliesaremainlydistributedinthesouthwestandnorthwestareaoftheWenchuanaftershocksarea.Itisshownthattheprecursorsofthefarsourceregionandthenearsourceareahavethecharacteristicsofoutwardexpansion.Duringtheβstage(between300to700daysbeforethemainearthquake),theanomaliesaredistributedinthesouthwestandnorthernregionoftheaftershockregion,showingalargerangeofanomalies.Duringtheγstage(includingγ1andγ2,300daysbeforethemainearthquake),therangeofanomalydistributioniswide,andtheanomaliesaredistributedinthesouthwestandnortheastoftheaftershockarea.Theanomaliesconvergedtoepicenter(γ1)inthefarsourceregionandexpandoutwards(γ2)inthenearsourceregion.Resultsoftheexperimentalstudyandmechanicalanalysisofearthquakepreparationprocessindicatethatthethree-stagecharacteristicsofprecursoryanomaliesintheprocessofearthquakepreparationmaybecontrolledbytheseismogenicbody,whichisaformofexpressionintheprocessofearthquakepreparationandauniversalfeatureduringtheearthquakepreparationprocess,whichhasacertainguidingroleinearthquakeprediction.
简介:UsingthedigitaltelemetricseismicwaveformdataofChengduandKunming,thisarticlestudiesthefocalmechanismsolutionsandtheapparentstressvaluesofalargenumberofsmallearthquakes,andthenanalyzesthedynamicvariationofregionalstressfieldsandthespatio-temporaldistributionofapparentstressvalues.TheannualvariationvaluesoftheazimuthofaverageprincipalstressfieldbeforetheMay12,2008M_S8.0WenchuanearthquakeintheSichuan-Yunnanregionwere58°from2003to2004,85°from2003to2005,61°from2006to2007and90°from2006toApril2008respectively.Inrecentyears,deflectionordisturbancesoccurredintheazimuthoftheaverageprincipalstressfieldintheSichuan-Yunnanregion.AnalysisshowsthatthismayberelatedtothechangeofstressfieldstatesofcrustalblocksbeforeandaftertheDecember26,2004M_S9.0Sumatraearthquakeandthe2008M_S8.0Wenchuanearthquake.Theratioofthrust-typeearthquakesintheSichuan-Qinghaiblockwasonthehighersideintheperiodfrom2006to2007,andthesourcefaultingtypeoftheregionalmoderateandsmallearthquakeshadchangedbeforetheM_S8.0Wenchuanearthquake.ThechangeofstateofthestressfieldisconsistentwiththechangesinblockdisplacementfieldsrevealedbyGPSdataandthecrustalshorteningvelocityverticaltotheLongmenshanfaultzone.Basedontheradiationenergycalculatedfromallbandsoftheseismicwaveform,thevalueofapparentstressσ_appisobtained.Thefluctuationshapeofthefittingtrendoftheapparentstressisrelatedtotheintensityofregionalseismicity.Itrevealsthatthemicro-dynamicfluctuationprocessoftheregionalstressvalueissimilartotheazimuthtransitionoftheregionalprincipalcompressivestressfield,whichcanbeusedtoprobeforpregnantphysicalprocesses.Areaswithahighervalueofapparentstressσ_apparepossibleareasofpotentialseismicrisk.Itcanbeseenfromthespatialdistributionofthemediumandshort-termapparen