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:ThispapercalculatesthestaticCoulombstresschangesgeneratedbyfourearthquakesintheYutianareaduring2008~2014separately,thendiscussesthetriggeringinfluence,theiraccumulatedCoulombstresschangesandtheirinfluenceonnearbyfaults.TheresultsindicatethattheMS5.5earthquakein2011andtheM_S7.3earthquakein2014arebothintheregionswheretheCoulombstresschangeispositive,thestresschangesare0.004MPaand0.021MPa,respectively,meaningtheyaretriggeredbypriorearthquakes.TheMS6.2earthquakein2012occurredintheplacewhereCoulombstresschangewasnegative,soitispostponedbythepriorearthquakes.TheimageofCoulombstresschangesoftheMS7.3earthquakein2014isinaccordwithaftershocks(ML≥3.0)distribution,butsomeregionsonthefaultwheretheCoulombstresschangeispositivehavefewaftershocks,andstrongaftershocksmayoccuratthesedistrictsinfuture.Inaddition,thispapercalculatestheCoulombstresschangeonnearbyfaults,andfindsthattheCoulombstresschangesofdifferentelementsintheGGCfaultareverydifferent,andmustreceivestrongtriggered-influence,thoughtheresultmaybeinfluencedbytheinputfinitefaultmodel,sothereisstillalargeearthquake-risk.TheGGN,PLC,PLWandLBWfaultswerealsotriggeredbythefourearthquakesoccurringbetween2008~2014.TheirmaximumCoulombstresschangesallexceed0.002MPa,sotheyalsohaveastrongearthquakehazard.
简介:从表征地震断层错动引起的地震强度的一个力学量(地震矩)出发,依据不同断层性质地震的地震矩与震级的统计关系,反演得到2003年8月16日巴林左旗—阿鲁科尔沁旗地震和2004年3月24日东乌珠穆沁旗地震的震级、断层面积、平均错距、破裂长度以及释放能量等震源参数。在利用不同机构提供的地震矩得到这2次地震面波震级的过程中发现,2004年3月24日东乌珠穆沁旗地震的面波震级明显大于2003年8月16日巴林左旗—阿鲁科尔沁旗地震的面波震级。考虑到地震波在传播过程中衰减、损失因素,2004年3月24日东乌珠穆沁旗地震的面波震级很有可能超过Ms6.0,而2003年8月16日巴林左旗—阿鲁科尔沁旗地震的面波震级为Ms5.7左右。
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: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:2015年7月3日新疆皮山Ms6.5级地震灾区地处塔里木盆地南缘,该地自然条件恶劣,经济极为落后,灾区农村的民房除了抗震安居工程建设的房屋外,还有大量抗震性能较差的民居,在地震中受损严重,经济损失较大。灾区大部分位于山前溢出带,地下水位浅、地基土层软弱等场地条件对地震动有放大作用,震害影响范围较大。灾后重建中应继续加大安居富民工程的经费投入力度。灾区北部人口密集,地基土层软弱,工程地质条件差,建议在今后的安居富民建设中加强地基处理。
简介:公元1590年7月,在甘肃临洮附近有破坏性历史地震记载“……坏城廓庐舍,压死人畜无算”。同月,青海东部的冰沟城(今乐都县东北)也因地震而城崩。在过去出版的地震目录中,均按两次地震列出,分别称为甘肃临洮5Y2级地震,震中烈度Ⅶ度:青海乐都5级地震,震中烈度Ⅵ度。根据史料考证和现场调查结果,综合分析认为,上述两次地震很有可能为同一次地震,其震中位于甘肃永靖东南的马衔山区,震中烈度达Ⅷ一Ⅸ度,震级6V2级左右,其发震构造很可能为兰州马衔山北缘断裂带的中西段。
简介:正Theauthorsthankthediscusserforhisinterestandcarefulreviewofthepaperandhisvaluablecomments.Theyalsowelcomethisdiscussion,becauseitgivestheauthorstheopportunitytoclarifyseveralpointswhichwerenotexplainedinsufficientdetailinthepaper,due
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(MD)震源深度(Km)震中烈度 地震类型 199203030602228118°10′24°06′118°06′24°12′漳浦海外(厦门南)48Ⅴ孤立型 表1中宏观震中是根据陆地上勾划的等震线推测的,在微观震中的北西20公里左右。二、地震烈度分布本次地震的波及面很广,闽东南沿海地区均明显有感,调查在Ⅴ、Ⅳ度两个区内进行。由于地震影响场只有一小半在陆地上,勾勒出的是Ⅴ、Ⅳ度两条等震线的半椭圆弧线(见图14-1)。图14-1 1992年3月3日漳浦海外地震等震线图Ⅴ度区:震中位于海上
简介:Twoaspectsofanewmethod,whichcanbeusedforseismiczoning,areintroducedinthispaper.Ontheonehand,theapproachtoestimatebvalueandannualactivityrateproposedbyKijkoandSellevollneedstousetheearthquakecatalogue.Theexistingearthquakecataloguecontainsbothhistoricalandrecentinstrumentaldatasetsanditisinadequatetouseonlyonepart.Combiningthelargenumberofhistoricaleventswithrecentcompleterecordsandtakingthemagnitudeuncertaintyintoaccount,Kijko’smethodgivesthemaximumlikelihoodestimationofbvalueandannualactivityrate,whichmightbemorerealistic.Ontheotherhand,thismethodconsidersthesourcezoneboundaryuncertaintyinseismichazardanalysis,whichmeanstheearthquakeactivityrateacrossaboundaryofasourcezonechangessmoothlyinsteadofabruptlyandavoidstoolargeagradientinthecalculatedresults.