简介:TheseismicwaveformoftheYutianMS7.3earthquake,XinjiangonFebruary12,2014wasrecordedclearlyandcompletelybytheDigitalSeismicNetworksofXinjiang,Qinghai,Tibet,andXinjiangHotanarray,sothemethodofjointlocationbyregionalseismicnetworkandseismicarraycanbeusedtoaccuratelydeterminetheearthquakesourcelocation.Thefollowingtechnologieswereusedintheprocessoflocation:(1)WeselectedseismicstationsequallylocatedaroundtheepicenteroftheMS7.3earthquakewithanaverageintervalofabout15degreesintheinitiallocation.(2)TherecordingwaveformsofYutianseismicstationwererotatedtotheradialandtangentialdirectionstopreciselyobtainthearrivaltimeofS-wavestodeterminetheepicentraldistance.(3)Thevelocitymodelwasusedinthedeterminationoflocationoftheepicenter,basedonthehistoricalrecordsofearthquakesintheareawithinaradiusof1.0°fromthesourceasthecenter,andthevelocitymodelisobtainedafterre-fittingandcalibration.(4)BasedonthewaveformrecordsoftheHotanseismicarray,themethodofwaveformbeamingwasusedtodeterminetheazimuthsandperformthecorrectionoftheepicenterlocationwiththeseazimuths.(5)Thedeterministicmethodwasusedtomeasurethesourcedepth.Finally,itisconcludedthattheYutianMS7.3mainshockhypocenterlocationis36.197°N,82.467°E,focaldepth12kmandoriginaltime17:19:48.2p.m.February12,2014.
简介:TheFebruary12,2014,MS7.3,earthquakeinYutian,Xinjiang,China,occurredasaresultofshallowstrike-slipfaultinginthetectonicallycomplexregionofthenorthernTibetanPlateau,withadepthof17km.ThisearthquakeoccurredseveralhundredkilometersnorthoftheconvergentIndia-Eurasiaplateboundary.TheepicenterlocationoftheYutianearthquake,36.1°N,82.5°E,is110kmnorthofYutianCounty,HotanPrefecture.AlargenumberofaftershocksfromML2.0toML3.0occurreduntil12:00oclock,February23,2014andthelargestaftershock,MS5.7,occurredat17:24p.m.,February12,2014.ThebandhvalueofYutiansequenceare0.70and1.29,respectively.ThewaitingtimemethodrevealsthatthestrongaftershocksaboveML4.5complywithalinearrelationship,whichisconsistentwiththecharacteristicsofamainshock-aftershocksequence.Furthermore,wecalculatethesourceparametersandanalyzetheruptureprocessbasedontheempiricalrelationshipsfortheYutianearthquake,andtheresultsindicateafrictionalundershootbehaviorinthedynamicsourceprocessoftheYutianearthquake,whichisalsoinagreementwiththelowerandsimilarbvaluescomparedwiththe2008MS7.3Yutianearthquakeandthe2012MS6.2Yutianearthquake.
简介:Wesuccessfullyemployanautomaticcentroidmomenttensor(CMT)inversionsystemtoinfertheCMTsolutionsoftheFebruary12,2014MS7.3Yutian,Xinjiangearthquakeusingnear-fieldseismicwaveforms(4°<△<12°)observedbythevirtualChinaseismicnetworks,whichhavebeenrecentlysetup.Theresultsindicatethatthiseventoccurredonaruptureplane(strike243°,dip70°,andrake-18°),showingleft-lateralstrike-slipfaultingwithaminornormal-faultingcomponent.Thecentroidinthehorizontaldirectionislocatednearly13kmeastoftheepicenter(36.123°N,82.499°E),andthebest-fittingcentroiddepthisaround10km.Thetotalscalarmoment,M0,isretrievedwithanaveragevalueof3.05×1019N·m,correspondingtomomentmagnitudeMW6.92.Mostoftheenergyisreleasedwithinabout14s.Moreover,wediscussaboutthepotentialapplicationofthissysteminearthquakedisasterdecision.
简介:ThepaperinvertsthefocalmechanismsolutionsoftheYutianM_S7.3mainshock,foreshocksandM_S≥3.5aftershocksbyusingtheCAPmethod,basedonthebroadbandwaveformsrecordedbytheXinjiangandTibetDigitalSeismicNetworks.TheresultsshowthattheM_S7.3strongearthquakeisofstrike-sliptypewithanormalfaultingcomponent,andcombinedwiththeanalysisoffocalstructureandtheaftershockdistribution,thenodalplaneIwithstrike241°,dip90°andrake-22°isconsideredtobetheseismogenicfaultplaneofthemainshock.ThedirectionofP-axisforthemainshockis194°,closetothenearNSdirectionoftheprincipalstressP-axisofhistoricalstrongearthquakesinthisregion.ThefocalmechanismsolutionoftheM_S5.4foreshockhasagoodconsistencywiththatofthemainshock.Amongthe18aftershocks,10areofstrike-sliptype,6areofnormalfaultingtypeand2areofthrusttype.70%oftheaftershocksinthesequencehaveafocalmechanismwithP-axisinthenear-NSdirection.ThefocaldepthsofthisM_S7.3earthquakesequencesaredistributedintherangeof5km-28km,withthemajorityinthedepthrangeof15km-20km,slightlydeeperthanthedepthof10kmofthemainshockascalculated.
简介:TheregionaltectonicbackgroundandcharacteristicsofactivefaultsoftheYutianMS7.3earthquakeonFebruary12,2014arediscussedinthispaper.AftertheanalysisoftheepicenterareaoftheMS7.3earthquakein2014andthefocalmechanismsoftheformerstrongearthquakesaroundit,theauthorsdeducedthattheseismogenicfaultoftheMS7.3earthquakeistheeastbranchoftheAshikulefault.TheMS7.3earthquakein2014andtheMS7.3earthquakein2008aretwostrongearthquakeeventsonthedifferentsectionsoftheAltunTaghfault,wherethefaultbehaviorchangesfromsinistralsliptonormalfaultingbecauseoftheextensionaltaileffectsinthesouthernendoftheAltunTaghfault.ItisconcludedthatthetwoMS7.3earthquakeshavethesamedynamicsource,andtheMS7.3earthquakein2008promotedtheoccurrenceoftheMS7.3earthquakein2014.Finally,wecalculatetheCoulombstresschangetotheseismogenicfaultoftheMS7.3earthquakein2014fromtheMS7.3earthquakein2008usingthelayeredcrustmodel.TheresultalsoshowsthattheMS7.3earthquakein2008acceleratedtheoccurrenceoftheMS7.3earthquakein2014.
简介:2015年4月25日尼泊尔廓尔喀地区发生Ms8.1级地震,本文分析了加德满都强震台站的强地震动记录特征,其水平向地震动表现为明显的脉冲地震动,脉冲周期约为6.0s,反映了近场地震动的方向性效应;处于深厚沉积层上的加德满都谷地对地震动有一定的放大作用,且主震的场地峰值频率向低频段偏移,出现明显的场地非线性反应;采用随机有限断层方法模拟的空间地震动分布与宏观地震烈度图符合较好,可以为分析宏观震害提供参考;通过与尼泊尔设计反应谱对比,得出在短周期与长周期段,加德满都台站的水平向地震动的反应谱远高于设计反应谱,说明即使严格按照尼泊尔建筑抗震规范设计施工的建筑结构也难以抵御此次地震的破坏.
简介:对新疆和静县乔霍特铜矿一带巴音布鲁克组火山岩岩石学、岩石化学、岩石地球化学进行了研究总结,认为该火山岩为钙碱性系列的玄武安山岩-安山岩-英安岩-流纹岩组合,具低TiO2、MgO、高Al2O3,高Fe2O3/FeO比值及富钠贫钾的特点,形成于大洋岛弧环境;在流纹岩中获得(430.33±0.99)Ma的LA-ICP-MS锆石年龄,指示巴音布鲁克组时代为志留纪。
简介:西准噶尔东部哈拉阿拉特山南麓乌尔禾地区新发现大量中基性岩墙群。岩墙群侵位于下二叠统佳木河组磨拉石建造中,展布方向与达尔布特大断裂延伸方向一致。岩墙群中采集的3个锆石U-Pb年龄样品测年结果分别为(286.3±4)Ma(n=18,MSWD=0.32,95%置信度),(286.5±5.6)Ma(n=10,MSWD=0.3,95%置信度)和(283.6±2)Ma(n=6,MSWD=0.57,95%置信度),误差范围内基本一致,据此确定该岩墙群形成于早二叠乌拉尔世(Cisuralian)亚丁斯克期(Artinskian)。中基性岩墙群具鲜明的与岛弧俯冲作用有关的地化特征,做为西准东部俯冲造山的地质记录,测年结果表明,西准东部的俯冲造山作用明显滞后于西部,整个西准地区俯冲造山作用结束的最终时限为早二叠世晚期。
简介:摘要简要分析国内现有盾构刀具磨损计算及其不足,分析盾构机刀盘配置特点、各项参数及在成都地铁3号线5标熊猫大道站~动物园站~驷马桥站两区间掘进施工过程中的推力、扭矩等参数。通过对盾构推力的计算及与实际统计值的校对,分析总结适合计算盾构刀具磨损的计算方法。为盾构刀具磨损理论计算和盾构换刀里程提出新思路,包括1)应用刀具磨损系数检测机检测不同刀具在不同地层的磨损系数,2)刀具换刀里程可以根据刀具磨损系数来反算,3)盾构出洞后的实际统计数据可用来验证和指导同类地层刀具磨损系数和相关参数设置。最后,指出渣土改良后刀具磨损系数测量是盾构掘进由未知向“可视”开启的“一扇门”,并提出在刀具磨损数据库模式下实现同步监测盾构刀具可用距离的想法。
简介:摘要随着科学技术的进步和生产力的发展,工程测量技术也得到了不断的革新。近几年,一些高精度、内容复杂、规模巨大的工程在各个国家兴建起来,各种测量新技术随之应用到工程领域中,例如GPS定位技术、数字化技术、地理信息(GIS)技术等,这些新技术的应用对工程测量施工质量具有重要的影响,在这种背景下,相关部门应积极利用测量新技术来提高我国工程施工的质量,以更好的促进经济的发展。
简介:利用NCEP的1°×1°资料,分析飓风"桑迪"温带变性前后物理量的特征和变化。结果表明:利用对流层低层、中层及高层的厚度场可立体直观地展现热带气旋中心热力结构的对称性,便于进行飓风温带变性的诊断分析。涡度场可诊断高空槽和飓风耦合的情况,两者的正涡度场连接后使热带气旋受到高空槽的影响开始变性。厚度变形场动力强迫上升、低层锋区抬升、强降水区凝结潜热正反馈作用和高空辐散加强等有利于飓风"桑迪"变性过程中深对流的维持及发展,并导致强上升区域向西偏离。飓风"桑迪"变性后暖心结构下降至对流层中低层,与强上升运动中心下降有关。适度的冷空气强度对飓风"桑迪"的加强有利,冷空气较弱飓风加强较慢,冷空气过强易破坏飓风的暖心结构,导致中心填塞。850hPa温度平流对变性后飓风"桑迪"的移动路径有一定的指示意义,飓风基本朝着冷平流中心指向暖平流中心的方向移动。