简介:AppendixA:Thederivationofequation(4)InFourierdomain,d2(x)=2x2istransformatedintod2(kx)=-k2x(A1)Whenequation(3)isnumericalyc...
简介:Therehavebeen12possiblelocationsoftheearthquakesoccurringintheSouthYellowSeasince1505.Inthispaper,thelocationoftheearthquakethatoccurredin1505hasbeendeterminedbythecollectionofmorehistoricaldataoftheinfluencedfield,referringtheisoseismaldataofearthquakeswiththeepicentralintensityⅨandcombininggeophysicalfielddatawithtectoniccondition,duetoitsgreatinfluenceonseismicsafetyassessmentofsomesignificantengineering.
简介:一、地震基本参数表1 地震基本参数表发震时间年月日时分秒震 中 位 置微 观宏 观东经北纬东经北纬参考地名震级(MS)震源深度(Km)震中烈度 地震类型 1975042504061781182°256°1183°256°德化雷峰3289Ⅳ主震型 按微观震中定位,应在德化佛岭乡附近,宏观震中位于其东面10公里左右的雷峰乡附近。本次地震的震级为全省测定的平均数ML。二、地震烈度分布据调查,地震时有感人数较多的为雷峰乡一带,约占调查人数的20%左右,其它地点,约在10%以下,有的只是个别人有感。故圈定雷峰附近为震中区,烈度为Ⅳ度。地震时人们先闻到地声似闷雷呼呼响,后感觉到木板墙、床、门在摆动。本次
简介:ThemainshockandaftershocksoftheHutubiMS6.2earthquakeonDecember8,2016wererelocatedbyapplyingthedoubledifferencemethod,andwerelocated477earthquakesintheHutubiregion.Theearthquakerelocationresultsshowthattheaftershocksaredistributedintheeast-westdirectiontowardsthenorthsideofthesouthernmarginoftheJunggarBasinfault,andaremainlydistributedinthewesternregionofthemainshock.ThedistancebetweenthemainshockafterrelocationandthesouthernmarginoftheJunggarBasinfaultisobviouslyshortened.Combinedwiththefocalmechanismandthespatialdistributionofthemainshockandaftershocks,itisinferredthatthesouthernmarginoftheJunggarBasinfaultisthemainseismogenicstructureoftheHutubiearthquake.
简介:ThetimeseriesofcoordinatesofalargenumberofGPSstationsintheworld,processedbyProf.GeoffreyBlewittwithGIPSYsoftwareareavailableathttp://geodesy.unr.edu.BasedonthetimeseriesofcoordinatesintheglobalreferenceframeofIGS08atmorethan250stationsofcontinuousGPSobservations,downloadedfromthewebsite,theco-seismicdisplacementsoftheM7.3KyushuearthquakeonApril16,2016inJapanandthepre-seismicstrainaccumulationsanddisplacementsintheregionalreferenceframewereobtained.ThestationofcontinuousGPSobservationatBJFSnearBeijinghasbeenquitestableindisplacementintheeasternpartofChinaformorethan17yearssincethebeginningofitsoperation,andthisstationisusedasthecorestationintheregionalreferenceframeforthepre-seismicdisplacementoftheKyushuearthquakeofM7.3.Themainfeatureofthepre-seismicdisplacementsoftheKyushuearthquakeischaracterizedbylockinginthecrustatandneartheepicenter.Theanomalouspre-seismicstrainaccumulationdevelopedinanareaofanomalousaccumulationoftheshearstraincomponentofγ1onthenortheastsideoftheepicenter,withincreasingsizeoftheareaandincreasingmagnitudeinγ1.Thelargestareacoveredbytheanomalousγ1isabout2000km2.ThechangeintheEcomponentatBJFSsinceNovember26,2015wascausedbythereplacementofthereceiverandtheantennaatthestation.Inordertostudytheshort-termchangeindisplacementsatstationsatandneartheepicenter,thetimeseriesat3stationswithcontinuousGPSobservations,2atSUWNandDAEJinsouthKoreaand1atBJSHnearBeijingwereanalyzed.Theanalysisshowsthatthedisplacementsatthe3stationshavebeenquitestableinthesamemannerineastAsia.Thus,BJSHisusedasthecorestationintheregionalreferenceframeofdisplacementandthedisplacementtimeseriesshowthattherewerenosignificantshorttermanomaliesbeforetheearthquake
简介:在2016年新西兰凯库拉Mw7.8地震中,北东一北东东向科科仁古断裂水平右旋位移量最大,为10-12m;北北西一近南北向帕帕提断裂垂直位移量最大,达到5—6m。对直接坐落在这2条地震地表破裂带或变形带之上的建筑物的破坏现场调查表明,尽管房屋出现歪斜,但上部主体部分基本完整,没有出现倒塌或部分倒塌现象,避免了人员伤亡。在无法回避活动断裂及其大震危险性的情况下,隔震系统的广泛采用可以有效地提高建筑物抵御地震灾害的能力。此次地震触发了数万个滑坡体,最大滑坡体可达数百万立方米。对沃罗村北边2处边坡失稳地带的考察结果表明,针对该地至少从2个方面进行了考虑和处置:一是在选址上,避开了突出山嘴等高陡坡地带;二是在房屋正对的山坡地带,种植或保护了茂密的树木,这既增加了山体的稳定性,又可以在地震中有效地减缓崩塌的石块对房屋的冲击。对比中国中东部一些大震,如1976年唐山7.8级地震和2008年汶川8.0级地震中触目惊心的巨大人员伤亡和财产损失,即使在人口密度与滑坡规模上存在明显不同,对新西兰凯库拉地震灾害现场的考察结果,还是在如何有效抵御地震灾害方面给我们提供了很好的启示。
简介:一、地震基本参数表1 地震基本参数表发震时间年月日时分秒震 中 位 置微 观宏 观东经北纬东经北纬参考地名震级(MS)震源深度(Km)震中烈度 地震类型 196804011705051181°247°117°32′24°54′华安新圩52Ⅵ+主余震型 宏观震中是取Ⅵ度等震线的中心位置,位于华安县新圩南,与微观震中有较大偏离,微观震中在同安县城西南,两者之间相距约60公里。二、地震烈度分布本次地震发生于我省地震队伍成立之前的1968年,现场调查工作在三年之后才补充进行。由于极震区的烈度达Ⅵ度强,民房遭受一定程度的损坏,故震中及Ⅵ、Ⅴ度等震级的确定是可信的,但Ⅳ度线就无从勾划了。图1-1为本次地
简介:Inthispaper,weadopttheobservationdataoftwo10HzYRY4-componentboreholestrainmetersandone100HzFBS-3BbroadbandseismometertostudytheresponsesoftheirobservationstotheApril11,2012MW8.6earthquakeoffthewestcoastofnorthernSumatra,andcomparetheresponsecharacteristicsduringthecoseismicstageafterpreprocessingofthedata.Weanalyzethespectrum’sdynamicprocessduringthecoseismicstagewiththeStransformationmethod,anddiscussthespectrum’sdetailsindifferentseismicphases.TheStransformationresultsofthedataofseismometerandboreholestrainmeteratthesamestationshowthatthecoseismicspectrumevolutionofthetwokindsofobservationaresimilartoeachotherandcanbecross-referencedinindentifyingthewavesignals,whichprovesthattheboreholestrainmetermeasurementsathighfrequenciesarereliable.
简介:一、地震基本参数表1 地震基本参数表发震时间年月日时分秒震 中 位 置微 观宏 观东经北纬东经北纬参考地名震级(ML)震源深度(Km)震中烈度 地震类型 199604211341391118°40′26°22′118°41′26°22′闽清湾口417Ⅴ水库诱发地震 现场调查所确定的宏观震中位于闽清湾口前洋村附近(见图22-1),与微观震中基本吻合,仅有2公里的误差。二、地震烈度分布自1993年3月底水口水库开始蓄水,5月份起就有诱发地震发生,后逐渐频繁,且震级加大。本次41级地震是震级最高的一次地震。经过现场考察,绘制出地震烈度分布图(图22-1)。图22-1 水口库区41级地震烈度分布示意
简介:PHSJ-4型PH计是我局第一台高精确度的PH计,应用到实际观测过程中,遇到许多影响观测质量的具体问题。本文针对PHSJ-4型PH计使用过程中遇到的乱码、测值突跳、电极老化快、合理分辨率的确定、温度干扰因素的控制等问题展开分析,做了大量的条件实验,结合该仪器的工作原理以及PH值所遵循的化学原理,指出要提高和保障观测质量,观测时必须做到如下几点:调节观测参数时用指腹轻按,出现局部黑屏、乱码现象可采用关机后重新开机解决;电极一定要浸泡在KCL保护液中,观测完毕清洗电极后一定要用滤纸把残余的蒸馏水擦干后再授泡在KCL保护液中以免降低电极保护液的保护功效,延长电极的寿命;水样要达到室温时才能进行观测;合理分辨率应设置在0.01PH档。
简介:TheQilianMountainactivesourcenetworkdatawasprocessedusingthemethodsofstacking,cross-correlationandinterpolation,andtheairguntraveltimevariationcharacteristicsofPandSwavesaroundtheJanuary21,2016MS6.4Menyua,Qinghaiearthquake.Theresultsshowthatabout6monthsbeforetheearthquake,therelativetraveltimeofthreestationsneartheepicentershowedadeclinedchange(traveltimedecrease),andsuchachangeoflowvalueanomalywasrecoveredabout3monthsbeforetheearthquake.Thetraveltimedecreasethenappearedagain,andtheearthquakeoccurredduringtherecoveryprocess.ThemaximumdecreaseoftheS-wavetraveltimewas18ms,andthechangeintraveltimereturnedtonormalaftertheearthquake.Thevariationtrendofthe3stationsisconsistent,includingtheS-wavetraveltimechangeofstationZDY38,whichisnearesttotheepicenterandchangedobviously,andthevariationrangeofthetraveltimeissmalleratthestationsafar.Thisvariationpatternisrelatedtothepositionoftheseismicsource.Theshortertraveltimemeansthevelocityincrease,whichmayberelatedtotheregionalstressaccumulation.
简介:TheFirstConferenceofthe4thSessionoftheSpecialCommitteeonSeismology,SSCheldinChengdu¥//The4thSessionoftheCommitteeonSeismology...
简介:Inthispaper,accordingtotheresultsofthesatelliteimageryinterpretationandfieldinvestigation,westudytheactivefeaturesandthelatestactivetimesoftheChuxiong-Nanhuafault,theQuaternarybasinsformationmechanism,andtherelationshipbetweenthefaultandthe1680ChuxiongMs6%earthquake.SeveralQuaternaryprofilesatLvhe,NanhuarevealthatthefaulthasoffsetthelatePleistocenedepositsoftheT2andT3terracesofLongchuanriver,indicatingthatthefaultwasobviouslyactiveinlateQuaternary,TheChuxiong-NanhuafaulthasbeendominatedbydextralstrikeslipmotioninthelateQuaternary,withanaveragerateof1.6-2.Omm/a.SeveralpullapartQuaternarybasinsofChuxiong,Nanhua,andZiwuetc.havedevelopedalongthefault.The1680ChuxiongMs6%earthquakeandseveralmoderateearthquakeshaveoccurrednearthefault.TheChuxiong-Nanhuafaultaretheseismogenicstructureofthoseearthquakes,thelatestfaultmovementwasinthelate-Pleistocene,andeventheHolocene.Inlargearea,theChuxiong-NanhuafaultandtheeasternQujiangfaultandtheShipingfaultcomposedasetofNW-trendingobliqueorientationactivefaults,andthemotioncharacteristicsareallmainlydextralstrikeslip.Themotioncharacteristics,liketheredriverfaultoftheSichuan-YunnanRhombicBlocksouthwesternboundary,areconcernedwiththeescapingmovementoftheSichuan-YunnanRhombicBlock.
简介:帕米尔高原位于地中海-喜马拉雅地震带上,晚新生代以来随着印度板块向欧亚板块持续不断地挤压汇聚,其构造运动是欧亚大陆最强烈的地区。高原腹地发育一系列近SN向正断层,包括近SN向的塔什库尔干正断层所处的帕米尔中部现代区域的构造应力场以EW向水平拉张为主。2016年11月25日发生的阿克陶Ms6.7级地震的发震构造为塔什库尔干断层分支的NWW向木吉盆地北缘断层,其具有右旋走滑兼正断性质。地震在震中附近产生同震地表形变带,全长约lkm,呈近SN--NNE向水平拉伸,发育近EW—NWW向的张裂缝,为地震破裂的产物,张裂缝的最大水平拉伸位移量和最大垂直位移量分别为46cm和16cm。地表破裂带中的NE和Nw向张剪裂缝只是连接贯通这些雁列的张裂缝,其水平相对位移量取决于张裂缝的水平拉伸量和张裂缝之间的几何关系。地表形变带表现的拉张性质与帕米尔高原腹地区域现代应力场最大主压应力为垂直向基本一致,可能与深部热物质上涌造成的上地壳拉伸有关。而地表形变带呈近SN向水平拉张,与区域近EW向拉张应力场之间存在显著差异,这可能是木吉盆地北缘右旋走滑正断层阶区局部应力场调整的结果。