简介：Basedontherelationshipbetweenrockphysicalpropertiesandatomicstructuresofchemicalelements,thispaperdissertatesthecharacteristicsbetweenthedifferenceandchangeinthecomprehensivephysicalpropertiesofrocks,suchasdensity,elasticity,electricalpropertyandradioactivity,etc.Theexamplesinthispapershowthatthechangeofthecomprehensivephysicalparametersofrocksreflectsthechangeofatoms,molecules,mineralsandtheirconstitutionsinrocks,andtherearesomecorrelationsbetweentheseparameters.

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简介：Thechangelawsofintensityofnearly200moderate-smallearthquakeswithMs=2.0~5.5occurringontheChinesemainlandsince1954havebeenanalyzedandarecomparedwiththatofmoderatelystrongearthquakes(Ms≥5.0).Theresultsshowthatthereisquiteobviousregionalityinthestatisticallawsbybothmoderate-smallearthquakesandmoderatelystrongearthquakes:attenuationofintensityinEasternChinaisslowerthanthatinWesternChinaandtheratioofthemajoraxistotheminoraxisofiso-seismallinesinEasternChinaissmallerthanthatinWesternChina.Theresultsalsoshowthatforafixedmagnitudetheattenuationofintensityofmoderate-smallearthquakesisfasterwhenintensityishigherthanV+andslowerwhenintensityislowerthanV-incomparisonwiththatofmoderatelystrongearthquakes.Furthermore,therealsohavebeensomedifferencesintheaspectsasintensity-magnituderelationbetweenstatisticallawsofmoderate-smallearthquakesandmoderatelystrongearthquakes.Thesedi

简介：Theexperimentalstudyofthechangeofwavevelocityinfaultregionsbeforeinstabilityoffrictionalslidingofrockswasconducted.Experimentsshowthatbeforetheinstabilityoffrictionalslidingofrocks,thechangeofwavevelocitycannotbeobservedalonglinesononesideofthefault,buttheprecursorofthedecreaseofwavevelocitycanbeobservedalonglinesacrossthefault.Therefore,whenwetrytopredicttheearthquakesofthestick-sliptypeinfaultregionsbyusingtheanomalyofwavevelocity,themeasuringlinesacrossthefaultsshouldbeselected.

简介：Theearth-resistivitychangerecordedbeforetheJingtaiearthquake(EQ).withMs=6.2at11geoelectricstationswithin400kmoftheEQwasdiscussedinthispaper,andthefollowingconclusionsaremade:1)imminentvariationsofearth-resistivitypriortotheEQwererecordedattheWuwei,DingxiandShandanstationsimmediatelybeforetheEQ;2)therecordabilityoftheimminentvariationsatastationwasrelatedtotheactivedeepfaultsandthestronglyactivefaultsinsideandoutsidethefocalzone,andtothecausativestressfieldaswell;3)thetemporalandspatialcharacteristicsoftheearth-resistivitychangeimmediatelybeforetheEQshowedthattheEQwasprobablyinducedbytheNNWdirectionstressfield(orbyanotheroneofsimilardirection)whichwasgreatlyincreasedduringashortperiodimmediatelybeforetheEQandthatthenorthernwallofthefocalfaultplayedamajorroleintheprocessoftheEQpreparationandoccurrenceoftheEQ.

简介：BytheaftershockfrequencyestimationmethodbasedonthecalculationofcoseismicstaticCoulombstresschangesandrate-andstate-dependentfaultconstitutivelaw,wecalculatethefrequencyof"direct"aftershocksoftheWenchuanearthquakerelatedtocoseismicstaticCoulombstresschangesinitsaftershockzoneandtheareasnearby.Itshowsthatthefrequencyissignificantlylowerthanthetruthinthemainrupturezone,especiallyinthesouthernrupturezone,duetothedecreaseofstresslevelontheruptureplaneofthemainshockresultingfromcoseismicCoulombstresschange.ThestudyalsoshowsthattheeffectoftheCoulombstresschangeonthedurationofaftershockactivityisassociatedwiththelowerlimitmagnitude.Thedurationisabout15-16monthsforaftershocksaboveML4.0,andcloseto60monthsforaftershocksaboveML3.5.Inthisperiod,theratioofthe"direct"aftershockscausedbycoseismicCoulombstresschangerangesbetween44.7%to48.6%,whichsuggeststhat,eveninthe"effective"periodofcoseismicCoulombstresschanges,abouthalfoftheaftershocksonthemainshockruptureplaneareindependentofcoseismicCoulombstresschanges.Itispointedoutthatthoseaftershocksmayberelatedtotheaftersliportheviscoelasticrelaxation,whicharetimedependentcases.

简介：Basedonlinearporoelasticandhydrogeologytheory,amathematicalexpressiondescribingtherelationshipbetweenwaterlevelchangeandaquifervolumestrainisputforward.Combinedwithearthtidaltheory,weanalyzetheresponsecharacteristicsfromwell-aquiferwaterlevelchangetoearthtideofvolumestrainandpresentamethodofvolumestraininversionfromwaterlevelchange.Comparingtheresultsofinversionwithrealobserveddata,wefoundthatthereisagoodconsistency.Thissuggeststhatthemethodofvolumestraininversionfromwaterlevelchangeisproper.Itwillofferareferenceforlearningabouthydrogeologycharacteristics,volumestrainandsearchingforprecursoranomalies.

简介：UsingthedigitaltelemetricseismicwaveformdataofChengduandKunming,thisarticlestudiesthefocalmechanismsolutionsandtheapparentstressvaluesofalargenumberofsmallearthquakes,andthenanalyzesthedynamicvariationofregionalstressfieldsandthespatio-temporaldistributionofapparentstressvalues.TheannualvariationvaluesoftheazimuthofaverageprincipalstressfieldbeforetheMay12,2008M_S8.0WenchuanearthquakeintheSichuan-Yunnanregionwere58°from2003to2004,85°from2003to2005,61°from2006to2007and90°from2006toApril2008respectively.Inrecentyears,deflectionordisturbancesoccurredintheazimuthoftheaverageprincipalstressfieldintheSichuan-Yunnanregion.AnalysisshowsthatthismayberelatedtothechangeofstressfieldstatesofcrustalblocksbeforeandaftertheDecember26,2004M_S9.0Sumatraearthquakeandthe2008M_S8.0Wenchuanearthquake.Theratioofthrust-typeearthquakesintheSichuan-Qinghaiblockwasonthehighersideintheperiodfrom2006to2007,andthesourcefaultingtypeoftheregionalmoderateandsmallearthquakeshadchangedbeforetheM_S8.0Wenchuanearthquake.ThechangeofstateofthestressfieldisconsistentwiththechangesinblockdisplacementfieldsrevealedbyGPSdataandthecrustalshorteningvelocityverticaltotheLongmenshanfaultzone.Basedontheradiationenergycalculatedfromallbandsoftheseismicwaveform,thevalueofapparentstressσ_appisobtained.Thefluctuationshapeofthefittingtrendoftheapparentstressisrelatedtotheintensityofregionalseismicity.Itrevealsthatthemicro-dynamicfluctuationprocessoftheregionalstressvalueissimilartotheazimuthtransitionoftheregionalprincipalcompressivestressfield,whichcanbeusedtoprobeforpregnantphysicalprocesses.Areaswithahighervalueofapparentstressσ_apparepossibleareasofpotentialseismicrisk.Itcanbeseenfromthespatialdistributionofthemediumandshort-termapparen

简介：与1°x的分辨率基于活跃外壳的块构造，全新统活断层和波速结构1°，为中国大陆的构造压力紧张域的一个二维的有限元素模型在纸被构造。用GPSmeasurements，然后，为模型的速度边界条件被推出中国大陆的今日的压力紧张地的年变化模式被模仿。结果证明(1)在中国大陆的最近的构造变形的一般模式被它的包围盘子的相互作用管理，哪个，印度板起一个主要作用。在中国大陆的西方有指导NNE的速度分布。最大值滑倒率出现在碰撞边界。指导北方的部件减少，当指导theeast的部件从南方逐渐地增加到北方并且从西方到东方时。在东方部分，有一个一般指导东方的运动，与在中国大陆的今日的构造应力场经历了的指导南方的部件(2)的某个数量最近的年里的改进的过程，并且这个过程介绍作为中心从Qinghai-Xizang(西藏)高原向东放射的一个一般模式。一般模式类似于周围的构造应力场，显示中国大陆上的当代的构造变形的继承。(3)最大的主要紧张介绍在东方在西方和low高的一个明显的模式。在西方的构造运动在东方是比那强壮的。Largeactive差错都位于最大的主要紧张的高值的地区。然而，紧张的大小在活跃的外壳的块的内部是更小的，它被这些差错围住。(4)四川云南区域的压力紧张地是唯一的。它不能被盘子的碰撞独自管理但是外部活跃的块的运动的联合，在下地壳或上地幔和特殊构造几何学的材料流动(例如东方喜玛拉雅的句法)也。

简介：Withtheimprovementofseismicobservationsystem,moreandmoreobservationsindicatethatearthquakesmaycauseseismicvelocitychange.However,theamplitudeandspatialdistributionofthevelocityvariationremainsacontroversialissue.RecentactivesourcemonitoringcarriedoutadjacenttoWenchuanFaultScientificDrilling(WFSD)revealedunambiguouscoseismicvelocitychangeassociatedwithalocalMs5.5earthquake.Here,wecarryoutforwardmodelingusingtwo-dimensionalspectralelementmethodtofurtherinvestigatetheamplitudeandspatialdistributionofobservedvelocitychange.ThemodeliswellconstrainedbyresultsfromseismicreflectionandWFSDcoring.Ourmodelstronglysuggeststhattheobservedcoseismicvelocitychangeislocalizedwithinthefaultzonewithwidthof*120mratherthandynamicstronggroundshaking.Andavelocitydecreaseof*2.0%withinthefaultzoneisrequiredtofittheobservedtraveltimedelaydistribution,whichcoincideswithrockmechanicalexperimentandtheoreticalmodeling.

简介：Amodelofdoublemediumaquiferisbrieflyintroducedinthispaper,apartialdifferentialequationaboutseepagemotionderivedbythetidalstressinthemodellayerisdeduced.ComparedthisequationwithBoultonequationusedintheunconfinedaquifer,anewlaggingsupplywatertermisobtained,whichestablishthephysicalbasisforinterpretingthephasedelayphenomenaofwellwaterlevelcausedbythesolidtide.Byanalyzingthepartialdif-ferentialequation,itisfoundthatthislaggingsupplytermisrelatedwiththefluctuationoftideoccurredinthedeepaquifer.

简介：Thisstudyinvestigatesdata-processingmethodsandexaminestheprecipitationeffectongravitymeasurementsattheDaligravitynetwork,establishedin2005.High-qualitygravitydatawerecollectedduringfourmeasurementcampaigns.Tousethegravitydatavalidly,somegeophysicalcorrectionsmustbeconsideredcarefully.Wefirstdiscussdata-processingmethodsusingweightedleastsquaresadjustmentwiththeconstraintoftheabsolutegravitydatum.Resultsindicatethatthegravityprecisioncanbeimprovedifallabsolutegravitydataareusedasconstraintsandifcalibrationfunctionsofrelativegravimetersaremodeledwithintheobservationfunction.Usingthisdata-processingscheme,themeanpointgravityprecisionisbetterthan12lgal.Afterdeterminingthebestdata-processingscheme,wethenprocessthegravitydataobtainedinthefourmeasurementcampaigns,andobtaingravitychangesinthreetimeperiods.Resultsshowthatthegravityhasaremarkablechangeofmorethan50lgalinthefirsttimeperiodfromApr–Mayof2005toAug–Septof2007.Tointerpretthelargegravitychange,ameanwatermasschange(0.6minheight)isassumedintheETOPO1topographicmodel.Calculationsoftheprecipitationeffectongravityshowthatitcanreachthesameorderoftheobservedgravitychange.ItisregardedasamainsourceoftheremarkablegravitychangeintheDaligravitynetwork,suggestingthattheprecipitationeffectongravitymeasurementsmustbeconsideredcarefully.

简介：IntroductionRegionalseismicitytriggeredbybigearthquakesaswellasattershocksinsourcezonecouldbedetectedduetothehighseismicmonitoringcapabilitytoday(Anderson,etal,1994;Bodin,Gomberg,1994;Caskey,Wesnousky,1997;Deng,Sykes,1996;Hill,etal,1993;King,etal,19...

简介：Rockexperimentresultsindicatethattheload/unloadresponseratio(LURR)ofrocksexpressedviastrainenergymayhavesingularornegativevalueafterthestressintherockreachesitsmaximumbeforerockfailureorwhentherockgoesintothestrain-weakeningphase.Theuniversalityofthisphenomenonisdiscussed.ExpressedviastrainorstrainenergyandthetraveltimeofPwave,thevariationformofthereciprocalofLURRduringtheprocessofrockfailurepreparationisderived.TheresultsshowthatafterasharpdecreasethereciprocalofLURRreachesitsminimumwhenthemainfractureoftherockisabouttoappear.Thisfeaturecanbetakenasanindicationthattherockmainfractureisimpending.

简介：ThecycleprocessofthetidalforcenichefortheLudianMs6.5earthquakeoccurringinLudianCounty,YunnanProvince,ChinaonAugust3,2014wascalculated.Theearthquakeoccurrednearthemiddlepointphase.Itindicatesthatthetypeofseismogenicfaultthatthetideforceactedonbelongstothethrustfault.Accordingtothetidalnichecycle,theabnormalOLR(OutgoingLong-waveRadiation)changewasanalyzedbasedonNOAAsatellitedataaroundthewholelandareaofChinabeforeandaftertheearthquake.TheresultshowsthattheOLRchangedevidentlywithtideforcechange.Temporally,thechangewentthroughtheevolutionprocessofinitialOLRrise→strengthening→abnormalpeaking→attenuation→returningtonormal；andspatially,theabnormalareawounditswayalongtheZhaotong-Ludianfaultandwentthroughascattered→conversion→scatteredprocess.Thisprocessissimilartothechangeprocessofrockbreakingunderstressloading.TheresultsindicatethatthetidalforceofacelestialbodycouldtriggeranearthquakewhenthetectonicstressreachesitscriticalbreakingpointandtheOLRanomalyisproportionaltotheseismictectonicstresschange.ItisofgreatusetocombineOLRandtidalforceinearthquakeprecursoryobservation.

简介：UsingthefocalmechanismsolutionsandslipdistributionmodeldataoftheTaiwanStraitsMS7.3earthquakeonSeptember16,1994,wecalculatethestaticCoulombstresschangesstemmingfromtheearthquake.Basedonthedistributionofaftershocksandstressfield,aswellasthelocationofhistoricalearthquakes,weanalyzetheCoulombstresschangetriggeredbytheTaiwanStraitsMS7.3earthquake.TheresultshowsthatthestaticCoulombstresschangeobtainedbyforwardmodelingbasedontheslipdistributionmodelisquiteconsistentwiththelocationofaftershocksintheareasfarawayfromtheepicenter.Ninetypercentofaftershocksoccurredinthestressincreasedareas.TheCoulombstresschangeisnotentirelyconsistentwiththedistributionofaftershocksneartheepicenter.ItisfoundthatCoulombstresschangecanbetterreflecttheaftershockdistributionfarawayfromtheepicenter,whilesuchcorrespondingrelationshipbecomesquitecomplexneartheepicenter.ThroughthecalculationoftheCoulombstresschange,wefindthatthestressincreasesinthesouthwestpartoftheMin-Yue(Fujian-Guangdong)coastalfaultzone,whichenhancestheseismicactivity.Therefore,itisdeemedthattheseaareabetweenNanpengIslandandDongshanIsland,wheretheMin-YuecoastalfaultzoneintersectswiththeNW-trendingShanghang-Dongshanfault,hasahighseismicrisk.

简介：StaticCoulombstresschangeinducedbyearthquakeslipisfrequentlyusedtoexplainearthquakeactivitiesandaftershockdistribution.However,someparametersfortheCoulombstresscalculationareunabletobewellconstrainedfromlaboratoryexperimentsandfieldobservations.DifferentparametersmaydirectlyaffectthepatternofstaticCoulombstress.ThestaticCoulombstresschangesinducedbytheWenchuanearthquakecalculatedbysixresearchgroupsarenotconsistentwitheachother.Toinvestigatehowtheparametersaffectthecalculationresults,wechangetheparametersinturnthroughmodelingandcomparetheresultsofdifferentcalculationparameters.Wefindthatgravity,positionandstrikeofreceiverfaultshavelittleinfluenceoncoseismicCoulombstresscalculations,butotherparameterscanchangethevalueandsignoftheresultsinvariousdegreesespeciallyaroundtheearthquakeruptureplane.ThereforetheuncertaintyanalysisofstaticCoulombstresschangeinducedbyearthquakeshouldbetakenintoconsiderationintheearthquakehazardanalysis.

简介：Usingatimeseriesmethodthatcombinesboththepersistentscattererandsmallbaselineapproaches,weanalyzed9scenesEnvisatASARdataovertheL’Aquilaearthquake,andobtainedaShocke’sdisplacementfieldanditsevolutionprocesses.Theresultsshowthat:(1)EnvisatASARclearlydetectedthewholeprocessesofdisplacementfieldoftheL’Aquilaearthquake,anddistinctvariationsatdifferentstagesofthedisplacementfield.(2)Preseismiccreepdisplacement?displacementmutationwhenfaulting?constantlysloweddownaftertheearthquake.(3)Theareaofthestrongestdeformationandgroundrupturewasalow-lyingovaldepressionregiontothesoutheast.Surfacefaultingwithinazoneofabout22km914km,withanorientationof135°,occurredalongtheNW-strikingandSW-dippingPaganica-S.Demetrionormalfault.(4)Inanalyzinganareaofabout54km959km,boundedbynorth–southaxistotheepicenter,thedisplacementfieldhassignificantcharacteristicsofawatershed:westwardoftheepicentershowsupliftwithmaximumof130mminline-of-sight(LOS),andeastoftheepicenterwasaregionwith220mmofmaximumsubsidenceintheLOS,concentratingontherupturezone,themajorityofwhichformedinthecourseoffaultingandsubsequence.

简介：OnthebasisofthepreviousstudiesofthelayeredcrustalmodelintheYutianarea,combinedwiththefieldGPScontinuousobservationdata,weroughlyestimatetheviscouscoefficientofeachlayer.Withtheviscoelastichorizontallayermodel,wecalculatetheviscoelasticco-seismicCoulombstresschangecausedbytheYutianM_S7.3earthquakes2008and2014respectively.BasedontheCoulombstresschange,usingthecalculationmethodof"direct"aftershockfrequency,wecomeupwiththetheoreticalearthquakefrequencydirectlyrelatedtothemainshockandtheco-seismicCoulombstresschangeinthestudyarea.Thenweputforwardamethod,basedonthecomparisonoftheoreticalandactualearthquakefrequencyorthecomparisonbetweentheoreticalandpracticalearthquakefrequency-distancedecaycurvefittingresiduals,toestimatethemagnitudeofamaximumsequentearthquake,directlyrelatedtothemainshockco-seismicCoulombstresschange.Resultscalculatedbydifferentmethodsshowthatthemaximumfollow-upearthquakemagnitudecausedbythecoseismicCoulombstresschangeliesfromM_S7.2toM_S7.5followingYutianM_S7.3earthquakein2008;butthatofthe2014YutianM_S7.3earthquakeisM_S6.3.TheformerisveryclosetotheYutianM_S7.3earthquakein2014.Becauseofthesamemagnitude,relativelyclosespatialdistance,shorttimeinterval,thesameregionoftheexternalforce,thestrongcorrelationbetweentwoseismictectonicandaclearstressinteraction,wethusconsiderthatthetwoYutianM_S7.3earthquakesin2008and2014constituteapairofgeneralizeddoubleshocktypeearthquake.Thisisconsistentwiththesequencetypecharacteristicofpast"doubleshock"earthquakesintheregion.Inthispaper,theinfluenceofthemagnitudelowerlimitandtheb-valueintherelationshipofG-Rontheresultsisdiscussed.Asaresult,whentheviscoelasticcoseismicCoulombstressvariationisdetermined,thelowerlimitofmagnitudehaslittleeffectonthemaximumsequentearthquakemagnitude

简介：TheprimarygoalofthedemonstrationprojectendorsedbytheScientificandTechnicalCommitteeforIDNDRin1992istoensurethatnationalagenciesareabletoassessseismichazardinaregionallycoordinatedfashionbyusingadvancedmethods.China,asaRegionalCenterofCentralSouthernAsia,hascontactedwithcountriesoftheregiontorealisticallypracticeseismichazardassessmentsofContinentalAsia.AtestarealocatedinthecollisionboundarybetweentheIndianandEurasianplateswaschosentoexaminetheseismichazardassessmentapproachintheregionalcoordinates.TheseismotectonicsandthreeversionsofseismicsourcesofthetestareaaredescribedinthispaperandundertheGlobalSeismicHazardAssessmentProgram(GSHAP),guidelinesanearthquakecatalogueofthetestareawasassembled.Becauseoftheincompletenessofearthquakedataindifferentcountries,weadoptdifferenttimewindowsfordifferentmagnitudeintervalsinordertoobtaintheseismicityparametersofsources.Byu