简介:TheemergenceofZhangHeng’sseismoscopehasaprofoundhistoricalbackground.ThispaperintendstoexploretheformationandmaterialbasisofZhangHeng’sscientificthought.Itappearsthatthesimpleintentionof"observingvisionsanddistinguishinggoodfortuneormisfortune"washismotivationtodeveloptheseismoscope.Tracingitshistoricalbackground,theauthorsproposedinthispaperthatthedevelopmentofthisseismoscopestartedaround128A.D.,andbasedonperceptualknowledge,twoideasaboutearthquakescameintobeing,i.e.,earthquakelocationcouldbejudgedaccordingtotheinstrumentshakingdirection,andtheearthquakeandearthsplitwereessentiallydifferent.Intheinstrumentmanufacture,ZhangHengadvocatedaprincipleof"makingutensilstoimitatecosmos".Bythisprinciple,thefollowingthreeproblemswerereadilysolved:theseismoscopeimitatedtheresponseofthesuspensionsystemtoearthquakes(i.e.naturalseismoscope).Technically,thetriggermechanismofthelatchwasusedforreference,anditrecordedthephysicalevidenceofearthquakeoccurrencebyaningeniouswayofaballdroppingfromadragon’smouth.Thesolutionofthesethreekeyproblemsleadtotheemergenceoftheseismoscopein132A.D.andthesuccessfuldetectionofanearthquakein134A.D.Hisinventiondeepenedhumanity’sknowledgeofnaturallaws,andpromotedthedevelopmentofscienceandtechnologyinthattimeandlater.
简介:HistoricaldataregardingZhangHeng'sseismoscopeisnotsingularproof.Actually,thefourearliesthistoricaldocuments,i.e.,ContinuationofHistoriographyofHanDynasty,HistoriographyoftheLaterHan,BookoftheLaterHanandDingRecordallhaverelevantrecordsofitsstructure,size,principle,responsetoearthquakeandactualapplications.Thesefiveaspectsaresupportedbyarchaeologicalresearch,unearthedculturalrelics,historicalearthquakesandmodernseismologicalstudy.Thesehistoricalmaterialscontainagreatdealofspecificinformationaboutthisancientseismoscope.Inconclusion,theauthenticityandreliabilityofZhangHeng'sseismoscopeareverified.
简介:EstimationofThomsen'sanisotropicparametersisveryimportantforaccuratetime-to-depthconversionanddepthmigrationdataprocessing.Comparedwithothermethods,itismucheasierandmorereliabletoestimateanisotropicparametersthatarerequiredforsurfaceseismicdepthimagingfromverticalseismicprofile(VSP)data,becausethefirstarrivalsofVSPdatacanbepickedwithmuchhigheraccuracy.Inthisstudy,wedevelopedamethodforestimatingThomsen'sP-waveanisotropicparametersinVTImediausingthefirstarrivalsfromwalkawayVSPdata.Modelfirst-arrivaltraveltimesarecalculatedonthebasisofthenear-offsetnormalmoveoutcorrectionvelocityinVTImediaandraytracingusingThomsen'sP-wavevelocityapproximation.Then,theanisotropicparameters0andearedeterminedbyminimizingthedifferencebetweenthecalculatedandobservedtraveltimesforthenearandfaroffsets.Numericalforwardmodeling,usingtheproposedmethodindicatesthaterrorsbetweentheestimatedandmeasuredanisotropicparametersaresmall.Usingfielddatafromaneight-azimuthwalkawayVSPinTarimBasin,weestimatedtheparameters0andeandbuiltananisotropicdepth-velocitymodelforprestackdepthmigrationprocessingofsurface3Dseismicdata.Theresultsshowimprovementinimagingthecarbonatereservoirsandminimizingthedeptherrorsofthegeologicaltargets.
简介:Thepost-earthquakerapidaccurateassessmentofmacroinfluenceofseismicgroundmotionisofsignificanceforearthquakeemergencyrelief,post-earthquakereconstructionandscientificresearch.TheseismicintensitydistributionmapreleasedbytheLushanearthquakefieldteamoftheChinaEarthquakeAdministration(CEA)fivedaysafterthestrongearthquake(M7.0)occurredinLushanCountyofSichuanYa’anCityat8:02onApril20,2013providesascientificbasisforemergencyrelief,economiclossassessmentandpost-earthquakereconstruction.Inthispaper,themeansforblindestimationofmacroscopicintensity,fieldestimationofmacrointensity,andreviewofintensity,aswellascorrespondingproblemsarediscussedindetail,andtheintensitydistributioncharacteristicsoftheLushan'4.20'M7.0earthquakeanditsinfluentialfactorsareanalyzed,providingareferenceforfutureseismicintensityassessments.
简介:Ingeneral,earthquakecyclerelatedtoearthquakefaultingcouldincludefourmajorprocesseswhichcouldbedescribedby(1)faultlocking,(2)self-accelerationornucleation(possibleforeshocks),(3)coseismicslip,and(4)post-stressrelaxationandafterslip.Asuddenstaticstresschange/perturbationinthesurroundingcrustcanadvance/delaythefaultinstabilityorfailuretimeandmodifyearthquakerates.Basedonasimpleone-dimensionalspring-sliderblockmodelwiththecombinationofrate-and-statedependentfrictionrelation,inthisstudy,wehaveapproximatelyderivedthesimpleanalyticalsolutionsofclockadvance/delayoffaultfailurescausedbyasuddenstaticCoulombstresschangeappliedinthedifferenttemporalevolutionperiodsduringanearthquakefaulting.Theresultshavebeenusedinthephysics-basedexplanationofdelayedcharacteristicearthquakeinParkfieldregion,California,inwhichthenextcharacteristicearthquakeofM6.0after1966occurredin2004insteadofaround1988accordingtoitscharacteristicreturnperiodof22years.Atthesametime,theanalyticalsolutionsalsoindicatethatthetimeadvance/delayinCoulombstresschangederivedbythedislocationmodelhasacertainlimitationandfundamentalflaw.Furthermore,wediscussedtheessentialdifferencebetweenrate-andstate-variableconstitutive(R–S)modelandCoulombstressmodelusedcommonlyincurrentearthquaketriggeringstudy,anddemonstratedthat,infact,theCoulombstressmodelcouldbeinvolvedintheR–Smodel.Theresults,wehaveobtainedinthisstudy,couldbeusedinthedevelopmentoftime-dependentfaultinteractionmodelandtheprobabilitycalculationrelatedtothetime-dependentandrenewalearthquakepredictionmodel.
简介:通过对2014年8月3日云南鲁甸6.5级地震震害开展实地调查,对灾区破坏情况进行总体介绍,并就各烈度区特征和建筑物震害、地震地质灾害、工程结构震害进行分析,初步得出本次地震的一些震害特点.一是灾区人口密度大,人员死亡较集中.人员死亡主要集中在Ⅷ和Ⅸ度区.二是地震振动强,灾区破坏严重.本次地震震源深度12km,极震区烈度高达Ⅸ度,震源破裂在11s内集中释放.三是抗震能力弱,房屋破坏严重.灾区属国家级贫困区,农村民居抗震能力弱,且多数民房坐落在河谷陡坡上,边坡效应加重房屋震害,重灾区砖木和土木房屋成片损毁、倒塌.四是灾区条件恶劣,救灾难度大.震区活动断裂密集发育、地质破碎疏松、地形崎岖不平,又恰值雨季,诱发极其严重次生地质灾害,导致人员伤亡,造成灾区大面积交通、通信、电力中断,救援物资与救援力量无法及时发挥作用.
简介:摘要富源信德矿区上部地层结构松散、破碎、钻孔坍塌严重。而且存在少量石灰岩,灰岩裂隙大,漏水严重。而设计的钻孔深度大。给施工带来很大困难,通过采取多级钻孔结构,并在钻进参数,冲洗液、钻头扩孔器上的合理应用,解决了施工难题,顺利完成了1204米深ZK502#钻孔。
简介:TheresistivityexperimentalmeasurementsofcoresamplesdrilledfromlowpermeabilityreservoirsofOrdosBasin,NorthwestChina,illustratethatthecementationfactorsarenotagminate,butvaryfrom1.335to1.749.Thisleadstoachallengefortheestimationofwaterandhydrocarbonsaturation.BasedontheanalysisofPurcellequationandassumptionthatrockresistivityisdeterminedbytheparallelconnectionofnumerouscapillaryresistances,atheoreticalexpressionofcementationfactorintermsofporosityandpermeabilityisestablished.Then,cementationfactorcanbecalculatediftheparametersofporosityandpermeabilityaredetermined.Inthefieldapplication,porositycanbeeasilyobtainedbyconventionallogs.However,itisatoughchallengetoestimatepermeabilityduetothestrongheterogeneityoflowpermeabilityreservoirs.Thus,theSchlumbergerDollResearch(SDR)modelderivedfromNMRlogshasbeenproposedtoestimatepermeability.BasedontheanalysisofthetheoreticalexpressionsofcementationfactorandSDRmodel,anovelcementationfactorpredictionmodel,whichisrelevanttoporosityandlogarithmicmeanofNMRT2spectrum(T2lm),isderived.TheadvantageofthismodelisthatalltheinputinformationcanbeacquiredfromNMRlogsaccurately.Inordertoconfirmthecredibilityofthenovelmodel,theresistivityandcorrespondinglaboratoryNMRmeasurementsof27coresamplesareconducted.Thecredibilityofthemodelisconfirmedbycomparingthepredictedcementationfactorswiththecoreanalyzedresults.Theabsoluteerrorsforallcoresamplesarelowerthan0.071.Oncethismodelisextendedtofieldapplication,theaccuracyofwaterandhydrocarbonsaturationestimationwillbesignificantlyimproved.
简介:摘要以连云港北固山隧道为工程背景,根据隧道设计图纸,结合现场实际地质情况,阐述了隧道右洞IV级、III级和II级围岩条件下的开挖施工方法与施工工序,为同类条件下隧道的设计与施工提供参考。关键词隧道;开挖;施工方法;围岩
简介:河北柳江盆地地质遗迹国家级自然保护区属于省级国土资源保护类科普基地,是一个集参观游览、科普教学、参与体验和科研实习与一体的独具特色魅力的地质风光景区。河北柳江盆地地质遗迹国家级自然保护区地质遗迹资源丰富,在13.95km^2的保护范围内完整地保存了新元古代至新生代中国华北地台在地球演化进程中的地壳运动、岩浆活动、沉积环境变化及生物进化等各种重要地质事件与地质现象,荟萃了中国北方20多亿年以来各个地质历史时期形成的24个组级地层单位、六大地壳运动不整合面和多种典型地质构造,具有极高的科学价值和社会价值,从而倍受国内外学术界的关注,使该地区成为理想的实习场所,享有“地学天然实验室”和“地学自然博物馆”的美誉。