简介：OnOctober27,2001,alargeearthquakewithMs6.0,namedtheYongshengearthquake,occurredalongtheJinshajiangsegmentofChenghaifaultinYongshengCounty,YunnanProvince.ItisthelargesteventtooccuralongtheChenghaifaultinthelast200years.Theseismo-geologicalsurveyshowsthattheseismogenicfault,whichistheJinshajiangsegmentofChenghalfault,takesleft-lateralstrike-slipasitsdominantmovementpattern.Accordingtodifferencesinverticalmotion,motiontime,landformsandscales,theChenhalfaultcanbedividedintoeightsegments.TheJinshajiangsegmenthasaverticaldislocationrateof0.4mm/a,farlowerthanthemeanrateoftheChenghaifault,about2.0mm/a.It'sdeducedthatthetwosidesofJinshajiangsegment'stuck'tightlyandhinderedthestrike-slipoftheChenghaifault.ThestrongearthquakedistributionbeforethiseventshowsthattheJinshajiangsegmentwasintheseismicgap.TheChenghaifault,asaboundaryoftectonicsub-blocks,makestheNorthwestYunnanblockandtheMiddleYunnanblockmoveclockwise,andtheirmarginsmoveoppositelyalongtheChenghalfault.InthemotionprocessoftheChenghaifault,structuralhindranceandtheseismicgapofstrongearthquakesarepropitioustotheconcentrationandaccumulationofstructurestress.Asaresult,theYongshengMs6.0earthquakeoccurred.TheSujiazhuang-ShangangfusegmentissimilartotheJinshajiangsegmentwithalowverticalmotionrateof0.3mm/aandintheseismicgap.Soit'spostulatedthatthesegmentmaybecomeanewstructurehindrance,andtheYongshengMs6.0earthquakemaytriggertheoccurrenceoffuturelargeearthquakesalongthissegment.

简介：ThispapersummarizesthelayoutoftheYunnanseismicELFelectromagneticobservationnetwork,siteselection,ELFelectromagneticinstrumentsystem,dataprocessingandotherconstruction.TheprincipleandmethodofusingtheELFelectromagneticwavetechniquetomonitorandpredictearthquakesareexpounded.ThelongtermmonitoringofELFelectromagneticfieldsiscarriedoutintheYunnanearthquakepronearea,andatthesametime,thechangesinelectricalparametersandspatialelectromagneticfieldsoftheregionalcrustalmediumstructurearemonitored.Thefunctionssuchasautomatic,quasirealtime,remotemonitoring,networkmonitoring,dataprocessingspecialization,dataservice,datasharingandindustrializationoftheELFelectromagneticobservationdatahavebeenrealized.Inordertocapturethedeepelectromagneticprecursoryinformationoftheearthquakes,serviceforearthquakepredictionresearch,whichhasbroadapplicationprospectsanddevelopmentpotential.ThroughtheresearchoftheseismicityofYunnaninthetrialrunperiodoftheproject,thepreliminaryresultsoftheextremelowfrequencyelectromagneticobservationoftheYunnanearthquakeinrecentyearsaregiven.TheelectromagneticprecursorsandtheelectromagneticeffectsoftheYangbiearthquakearerecorded.Inthe3-monthperiodbeforetheearthquake,thepowerspectrumoftheelectricandmagneticfields,theapparentresistivityandtheimpedancephaseintheobservedsignalsareallabnormal,andgraduallyincreasedwithtime.Themaximumvalueisreached20daysbeforetheearthquake,andanearthquakeoccurswhenthechangeisrestoredtonormal.

简介：辽宁是历史地震资料比较缺乏的地区,深入研究历史疑难地震,尤其是确认一些破坏性地震,对补充已有的地震目录和开展地震预测及工程场地地震安全性评价有重要作用。在历史地震研究中认真考查,论证已有的地震史料是最主要的手段和方法。但是若能在此基础上,利用现代地震资料,按＂地震重复＂发生理论反推一些历史上可能存在的破坏性地震,也可以认为是对历史地震研究方法的一种补充。按照这一思路,本文在进一步分析地震史料的基础上,通过与现代地震活动图像和大地震震害现象的对比,确认辽宁地区1509年4月21日的地震是一次破坏性地震,并对1552年10月27日的地震做了讨论。