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本论文是一篇关于回归分析方面论文怎么写,关于文中英文摘要,英文摘要相关毕业论文的格式范文。免费优秀的关于回归分析及模型及工程力学方面论文范文资料,适合回归分析论文写作的大学硕士及本科毕业论文开题报告范文和学术职称论文参考文献下载。

5.1地震的触发作用.结果表明,这几次强震在被触发地震上产生的动态应力峰值都超过地震触发阈值.第二,被触发地区小震突然增强.我们利用小地震频度变化探讨了1990年以来部分地震在南北地震带上的触发作用,并以2001年昆仑山口西8.1地震对四川,甘肃等地地震活动的触发作用为例进行了分析.总的看来,南北地震带易于被触发地震活动,但是不同地区的地震对南北地震带的触发作用不同,这可能与地质构造有关系.

地震动态应力研究之所以复杂,因为它还受到很多因素影响:主震参数和被触发地区构造,同时还有时间延迟问题.在计算主震在被触发点的应力张量时,主震的参数影响非常大.改变断层三要素(走向,倾角,滑动角),破裂时间以及破裂时的上升时间对最终计算的动态应力大小和变化趋势都有很大影响,改变主震地震矩和发震断层的大小只是影响了计算结果的大小,其趋势没有改变.大部分主震参数的变化都会影响到最后的计算结果,所以在计算地震产生的动态应力变化时,应该获得更准确的主震参数.构造区对地震动态触发影响也非常大,研究结果表明,大部分被触发的地震活动发生在地热或火山区及扩张性块体上,同时也在挤压性块体上发生动态触发的少量证据.动态应力对走滑和正断层地震触发更明显.强震面波到达后被触发地区不久可能触发当地地震活动,但是还是很多被触发的地震具有时间延迟,延迟时间从几天到几个星期不等.

总之,我通过硕士论文研究,改进了动态应力触发计算方法和程序,计算了南北地震带几次被触发地震的动态库仑应力变化,同时深入探讨了主震参数,触发地区构造特征对地震动态应力触发的影响,还初步研究了地震动态触发时间延迟问题,在研究过程中也发现了一些值得今后进一步研究的问题.

关键词:地震应力触发,库仑摩尔圆,构造块体,触发机理

ResearchonDynamicStressTriggeringatChineseNorth-SouthSeismicBeltinRecentYears

ZhangBin

ABSTRACT

Seismicstresstriggeringpointstotheinfluenceinducedbyoneearthquaketothenearbyandremoteseismicactivity,includingstaticstresstriggeringanddynamicstresstriggering.Scientistshavestudiedstaticstresstriggeringforalongtimeandhavegotlotsofachievement.Ontheotherhand,researchingondynamicstresstriggeringwasscarce.ThetimeweindeedresearchedonseismicdynamicstresstriggeringwasaftertheLandersearthquakeof1992,USA.Asdynamicstresstriggeringhassuperiorityinexplainingremotetriggering,soitisdevelopedrapidlyinrecentyears.ChinalocatesbetweenthePacificOceanseismiczoneandtheAsia-Europeseismiczone,soChinesemainlandanditsperipheryhasmorestrongshocks.AlthoughChineseseismologistsstudyseismicdynamicstresstriggeringlater,itisnecessarytostudyseismicdynamicstresstriggeringinChina.InordertoexploreChineseseismicdynamicstresstriggering,wetakeChineseNorth-Southseismicbeltasanexampleinthisarticle.

First,wesummarizedthedevelopmentofseismicdynamicstresstriggeringathomeandabroadsystematically,includingtheexistedevidenceofdynamicstresstriggering,currentsituation,triggeringmechanismandsoon.FromLandersearthquakein1992,seismologistsbegantoseekevidenceofdynamictriggeringonaglobalscale.Themainexistentevidenceatpresentincludes:seektriggeredearthquakeswarmandsingleearthquakeinseismicfrequencymap,findnewtriggeredearthquakebydigitalfilter,co-seismchangeandstresssteprecordedbystraininstrument.Thetriggeringmechanismincludescoulombfailuremodel,rate-statemodelandporepressureexpansionetc.ThereasonswhythestudyondynamicstressaresolessinChinamainlymayberelyontheplexityoftheputation.AfterSumatra8.7magnitudeearthquakein2004,someseismologistsstarttostudydynamicstresstriggeringinChina.

Themainmethodsofputingdynamicarereflectivitymethodandthediscretewavenumberdepositionmethod.Itinvolveslotsofmathematicsfunctions,includingBesselfunction,Greenfunction,ReflectivityfunctionandBouchonslopefunctionetc.Thephysicalprocessrelatedisalsoplicated:breaktimescattering,Greenfunctionconvolutionanddifferentinfrequencyareaetc.Accordingtosomepredecessors'formulae,wededucedseismicdynamicstresscalculatingformulaandrewrittedpartFORTRANprocedurethatCottonprovided.Inordertocalculatecoulombstressontriggeredfault,weconnectedFORTRANprocedurewithMATLAB.Atthesametime,werealizedtheMATLABprocedurevisualizationinterfaceforcalculatinganddrawing.ThecalculationofSeismicdynamicstressprisedtwosteps:first,calculatesixponentofstresswithFROTRANprocedure,second,calculatedynamicstressontriggeredfaultanditscurve.

Withthementionedmethodandprocedureofcalculatingseismicdynamicstressabove,weresearchedthetriggeredsituationbysomestrongearthquakesinChinesemainland.AstheNorth-SouthseismicbeltisarepresentativeoneinChinesemainland,sowetakeitastheresearchingzone,andstudymainlyfromtwoaspects.First,calculatestresstensorandcoulombstressintriggeredarea,including8.0earthquakeof2000inSumatratriggered5.8earthquakeofJingtaiinGansuand6.5earthquakeofBurma,7.9earthquakeof2003inborderofChina,RussiaandMongoliatriggered6.1earthquakeofMinle-Shandanand5.2earthquakeofMinxianinGansu,8.7earthquakeof2004inSumatratriggered5.1earthquakeofShuangbaiand5.1earthquakeofSimaoinYunnan.Theresultsshowthatthedynamicstresspeakvalueontriggeredfaultproducedbytheseveralstrongshocksallexceedstotriggeringthresholdvalue.Second,thesmallearthquakeswerestrengthenedabruptlyintriggeredarea.WediscussedthetriggeringeffectontheNorth-Southseismicbeltbyusingthechangeofsomeearthquakesfrequencysince1990.Atthesametime,wetakewestKunlunmountainspass8.1earthquakeasanexampletoanalysetriggeringeffectinSichuanandGansuprovinces.Allinall,theearthquakeactivityistri

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