简介:AppendixA:Thederivationofequation(4)InFourierdomain,d2(x)=2x2istransformatedintod2(kx)=-k2x(A1)Whenequation(3)isnumericalyc...
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 198305121504481159°251°11598°2501°武平武溪4212Ⅴ主余震型 据调查,宏观震中位于微观震中东南12公里处的武平武溪附近。二、地震烈度分布本次地震的有感范围涉及福建、江西、广东三省交界地区,调查工作主要在福建省武平境内进行,江西省境内由江西省地震办协助调查,广东境内用虚线连接。调查中根据人的感觉,结合民房轻微损坏情况,勾划出Ⅴ、Ⅳ度两条等震线(见图9-1)。图9-1 1983年5月21日武平地震等震线图Ⅴ度区
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:TheYutianearthquakewithM_S7.3happenedonFebruary12,2014.Theprecursormonitoringabilityisweakinthatarea.Wefoundtendencyanomaliesandmiddle-andshort-termanomaliesfrommetalpendulumtiltmeasurementsinHotanseismicstationbeforetheearthquake.AndwealsocomparedtheanomalieswiththatoftheM_S7.3YutianearthquakeonMarch21,2008.Thetendencyanomaliesmeasuredbythemetalpendulumtiltmeterappearedsince2012astiltingeastward.Whilethemiddle-andshort-termanomalieswerecharacterizedbyacceleration,pauseandrapidchangeoftiltrateintwodirections.Thetendencyanomaliesofmetalpendulumtiltrecordsarethesamebeforethetwoearthquakes.Theybothhappenedintheeastdirection.However,therearedifferencesinduration,characteristicandearthquakeintervalsforthemiddle-andshort-termanomalies.
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 1981122912261172°256°1171°256°连城丘家山3211Ⅴ小震群 表中的宏观震中是根据现场调查所圈定的Ⅴ度线推测的,位于微观震中的南西方向约6公里的丘家山林场附近。震源深度则是依据经验公式计算结果推断的。二、地震烈度分布本次地震震中地处山区,强度小,地表破坏轻微,主要根据人的感觉及房屋的轻微损坏与否进行评定,划分出Ⅴ、Ⅳ度两区(见图8-1)。图8-1 1981年12月29日连城丘家山地震等震线图Ⅴ度区为极震区。Ⅴ度等震
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: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:Thispaperintroducesthegeologicalstructurebackgroundaroundthe2014YutianM_S7.3earthquakearea,investigatesandanalyzestheregimeofsmallearthquakeactivityandthecharacteristicsofregionalseismicitypatterninXinjiangbeforetheearthquake,andcomparesthecharacteristicsoftheregionalseismicactivitywiththe2008YutianM_S7.3earthquake.Theresultsshow:12~3yearsbeforethe2014YutianM_S7.3earthquake,Xinjiangwasinaseismicactivestatewithstrongearthquakeoccurringsuccessively,andbeforethe2008M_S7.3earthquake,Xinjiangwasinthequietstateofmoderate-smallearthquakeswithM3.0~4.0.2BeforethisYutianM_S7.3earthquake,theregionalseismicactivityshowedashort-termanomalyfeature,thatis,seismicityofM≥5.0earthquakessignificantlyincreasedontheAltunseismiczoneandinthesourceareathreeyearsbeforetheM_S7.3earthquake,whileafiveyearlongquiescenceofseismicityofM≥4.0earthquakesappearedontheeastofthesourceareainarangeofabout440km.SixmonthsbeforethisM7.3earthquake,thereexistedseismicgapofM3.0~4.0earthquakesandnear-conjugateseismicbeltmagnitude3.0and4.0inthesourcearea.3ThestateofstrongearthquakeactivityandtheseismicitypatternofsmallearthquakesbeforethisYutianM_S7.3earthquakeweresignificantlydifferenttothatbeforethe2008YutianM_S7.3earthquake,andthismayberelatedtothedifferentseismogenicenvironmentsofthetwoM_S7.3earthquakes.
简介:ThesourcemechanismsolutionforJuly12,1995earthquakewithMS=7.3,ontheboundarybetwenChinaandMyanmarSHUTIANMA1)(马淑田)andJIANGUO...
简介:本文通过对记录到2015年天津港"8·12"爆炸的32个台站的三分量数字地震波形进行倒谱分析,得到了以下结论:(1)2个主要爆炸的发生时间间隔约为32.3s;(2)爆炸-2发生在爆炸-1的西北侧约353°处;(3)依据这些记录的倒谱,无法判定在爆炸-1前是否还存在微小的爆炸。以上结论均与前人研究成果吻合。由于倒谱叠加采用的是全波形,对滤波频带不敏感,因此,在检测发生在同一地点的多次爆炸或其它类似事件(如核爆)上有一定的优势。
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:TheFirstConferenceofthe4thSessionoftheSpecialCommitteeonSeismology,SSCheldinChengdu¥//The4thSessionoftheCommitteeonSeismology...
简介:Micro-aftershockswithmagnituderangeof1.5-4aroundtheWenchuanearthquakeepicenter,thesouthernpartoftheLongmenshanfaultzone,exhibitgoodfrequency-magnitudelinearrelationships,thusenablingb-valueanalysis.Theaverageb-valueformicro-aftershocksofM1.5-4fromJulytoDecemberof2008inourlocalstudyregionisabout0.88,similartotheb-valueforallaftershocksofM3.0-5.5fromMay,2008toMay,2009alongthewholeLongmenshanfaultzone.Thesimilaritybetweenthelocalandregionalb-valuespossiblyindicatesthatthesouthernpartoftheLongmenshanfaultzonehassimilarseismogenicenvironmenttothewholeLongmenshanfaultzone.Alternatively,itmayalsoimplythatb-valuesderivedfromalleventswithoutconsiderationofstructuralvariationcannotdiscriminatelocal-scaletectonicinformation.Thepresentstudyshowsthattheb-valuefortheWenchuanearthquakemicro-aftershocksvarieswithdifferentregions.Theb-valueinsouthwestoftheYingxiutownishigherthanthatinthenortheastoftheYingxiutown.Thehighb-valueinthesouthwestpartwheretheWenchuanearthquakemainshockhypocenterlocatedindicatesthatthecurrentstressaroundthehypocenterregionismuchlowerthanitssurroundingarea.Theb-valuesarealsodependentondepth.Atshallowdepthsof<5km,theb-valuesareverysmall(~0.4),possiblybeingrelatedtostrongwaveattenuationorstrongheterogeneityinshallowlayerswithhighcontentofporosityandfractures.Atdepthsof~5-11km,wheremostaftershocksconcentrated,theb-valuesbecomeashighas~0.9-1.0.Atthedepthbelow~11km,theb-valuesdecreasewiththedepthincreasing,beingconsistentwithincreasingtectonichomogeneityandincreasingstresswithdepth.
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.