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:Thenon-tidalvariationgainedfromcontinuousgravityobservationsinstationsusuallyreflectstheregionalcontinuousgravitychanges.Inthispaperwefocusonstudyingthenon-tidalvariationofBaijiatuanstation,Beijingwheretherearetwodifferentgravimeters(namely,L&R-804andPET-031).Basedontheoriginalrawtidalrecordsoftwogravimetersfrom2008to2011,wefirstremovevariousinterferencefromrawdatabythestandardproceduresoftware-Tsoft;thenwemodelthesolidearthtides,oceantidalloadingandpoletidethroughrelatedparameters;afterthatweadoptanewsegmentedpolynomialfittingmethodbasedonTsofttofitthecomplexdriftofspringgravimeter;andfinallywecalculatetheatmosphericloadingeffectsbyalinearregressionmodel.Afteraseriesofprocessingwegainthenon-tidalvariationofthetwogravimetersatBaijiatuansite,Beijing.Furthermore,toanalyzethenon-tidalvariationpreliminarily,westudythemaincomponentofrelatedtidaldatabypowerspectraldensity.Comparingthenon-tidalvariationoftwodifferentgravimeters,wefindseasonalfluctuationsinnon-tidalresults,whichareinaccordancewiththewaterstoragechange.Therefore,wetakeintoaccounttherelevanceofgravitychangesandwaterstoragebasedonthegravitydataofGRACEandwaterdataoftheCMAPmodelfrom2003to2011atdifferentsitesintheChinesemainland(Beijing,Chengdu,ShenyangandShiquanhe),andmakeapreliminaryanalysisontherelationshipbetweengravitychangesandwaterstorage.
简介:作为要学习的区域拿欧洲的主要陆地,新卫星重力技术的潜力:追踪的satellite-to-satellite(SST)并且与SST模型一起改进地区性的重力场模型的精确性被调查。这些模型的缺点被讨论。与是的GPM98C参考,几个另外的模型,的严肃异例剩余最近的SST全球重力场模型(EIGEN系列和GGM系列),被计算并且比较。在选择区域,有期刊性质的一些系统的错误在EIGEN和GGM存在的比较表演的结果是在高度和顺序的S系列模型。没在经典严肃模型被显示出的一些信息在EIGEN和GGM的S系列模型的低、中间的度和顺序被检测。最后,SST模型的有效的最大的度和订单被建议。
简介:Thispaperaimsatinvestigationofthedynamicpropertiesofgravitycageexposedtowavesbyuseofanumericalmodel.Thenumericalmodelisdeveloped,basedonlumpedmassmethodtosetuptheequationsofmotionofthewholecage;meanwhilethesolutionsofequationsaresolvedbytheRunge-Kutta-Vernerfifth-orderandsixth-ordermethod.Physicalmodeltestshavebeencarriedouttoexaminethevalidityofthenumericalmodel.Theresultsbythenumericalsimulationagreewellwiththeexperimentaldata.
简介:Basedonunifiedequivalentharmonicloadingonseabedfoundationandenergyapproachsuggestedbytheauthors,thedevelopmentofdynamicporewaterpressureandstabilityofsoilfoundationforthevibrationofoceangravitystructuresexcitedbyrandomwaveloadingareanalysed.Itmaybeseenthatthepresentmethodforthestudyofdynamicproblemsofoceangravitystructuresoilfoundationsismorereasonableandconvenient.
简介:为测试作为这个区域拿中国,新卫星严肃技术的潜力,为改进地区性的重力场模型的精确性追踪的satellite-to-satellite被学习。与是的WDM94引用,三个模型,的严肃异例剩余最近二个优雅全球重力场模型(EIGEN_GRACE02S,GGM02S)并且EGM96,被计算并且比较。为在三个模型的剩余之中的差别的原因被讨论。在剩余之间的Thecomparison证明在选择区域,EIGEN_GRACE02S或GGM02S比在更低的度部分(不到110度)的EGM96好。通过模型严肃异例剩余的分析,另外,有期刊性质的一些系统的错误在EIGEN和GGM模型,的更高的度部分存在,这被发现结果能也在SST严肃数据的确认作为引用被拿。
简介:Spatialandtemporalvariationof gravity fieldinthecapitalregionChang-CaiHUA;(华昌才)YongGUO;(果勇)Duan-FaLIU;(刘瑞法)GangXIAO;(肖钢),J.T....
简介:Seismicsafetyassessmentofgravitydamshasbecomeamajorconcerninmanyregionsoftheworldwhiletheeffectsofverticalseismicaccelerationsontheresponseofstructuresremainpoorlyunderstood.Thispaperfirstinvestigatestheeffectofincludingverticalaccelerationsintheslidingresponseanalysisofgravitydamssubjectedtoarangeofhistoricalgroundmotionrecordsseparatedintwogroupsaccordingtotheirsource-to-sitedistance.Analysesshowedthattheincidenceofverticalaccelerationsontheslidingresponseofgravitydamsissignificantlyhigherfornear-sourcerecordsthanforfarsourcerecords.Thepseudo-static30%loadcombinationrule,commonlyusedinpracticetoaccountforthenon-simultaneousoccurrenceofthepeakhorizontalandverticalaccelerations,yieldedgoodapproximationsoftheminimumsafetyfactorsagainstslidingcomputedfromtime-historyanalyses.Amethodforempiricallyestimatingtheverticalresponsespectrabasedonhorizontalspectra,accountingforthedifferenceinfrequencycontentandamplitudesbetweenthetwocomponentsisinvestigated.Resultsfromanalysesusingspectrumcompatiblehorizontalandverticalsyntheticrecordsalsoapproximatedwelltheslidingresponseofagravitydamsubjectedtoseriesofsimultaneoushorizontalandverticalhistoricalearthquakerecords.
简介:Thepressuregradientofthelithosphereisakeytoexplainingvariousgeologicalprocesses,andvariesalsointimeandspacesimilartothegeothermalgradient.Inthispaperacorrelationformulaofgeothermalgradientsandpressuregradientswasbuiltwiththethermocomprestioncoefficients.Basedonthisformula,thearticlehasstudiedtherelationbetweenthepressuregradientsandthegeothermalgradientsinthelithosphere,andtheresultsindicatethatthepressuregradientinthelithosphereisnonlinear,anditsminimumvalueisthelithostaticgradient,andthatthepressuregradientofthelithospherewillincreaseobviouslywiththecontributionofbothgeothermalandgravity,andcouldbetwicetimesmorethanthelithostaticgradient.
简介:Theproblemsoftheearth'sgravityfields'visualizationarebothfocusandpuzzlecurrently.Aimingatmultiresolutionrendering,modelingoftheEarth'sgravityfields'dataisdiscussedinthepaperbyusingLODalgorithmbasedonQuadTree.First,thispaperemployedthemethodofLODbasedonQuadTreetodivideuptheregionalgravityanomalydata,introducedthecombinednodeevaluationsystemthatwascomposedofviewpointrelatedandroughnessrelatedsystems,andtheneliminatedtheT-cracksthatappearedamongthegravityanomalydatagridswithdifferentresolutions.Thetestresultsdemonstratedthatthegravityanomalydatagrids'renderingeffectswereliving,andthecomputationalpowerwaslow.Therefore,theproposedalgorithmwasasuitablemethodformodelingthegravityanomalydataandhaspotentialapplicationsinvisualizationoftheearth'sgravityfields.
简介:DifferencesbetweentheCenozoicandpre-CenozoicstrataandstructuresinthemiddlesouthSouthYellowSeaareanalyzedusinghigh-resolutionairbornegravitydatacombinedwithdatafromoffshorewells,seismicexplorationandtheregionalgeologicalbackground,usingforwardandinversemethods.WediscusswhyhydrocarbonexplorationhassofarfailedintheSouthYellowSea,andputforwardalternativefutureexplorationplans.TheresultsshowthattherearethickCenozoicstrataoverJurassic–CretaceouscontinentalstratainthesouthernbasinoftheSouthYellowSea,contrastedwiththickMid-Paleozoicmarinestratapreservedinthemiddleupliftarea.Inthemid-southernSouthYellowSea,airborneBouguergravityanomaliesarefragmentizedwithscatteredlocalanomalies.ManytensilenormalfaultsandminorfaultblocksoccurintheCenozoicstrata.Incontrast,reversefaultsandnappestructuresarefoundinpre-Cenozoicstrata.Theessentialreasonsforthelackofabreakthroughinhydrocarbonexplorationarethecomplexityofgeologicalstructures,hydrocarbonaccumulationenvironments,seismic-geologicconditions,andthedifficultyofinterpretingandunderstandingthesefeatures,ratherthananimbalanceofexplorationframework.HydrocarbonexplorationshouldbetargetedatMid-Cenozoiccontinentalstrata,especiallyofPaleogeneage,inthemiddletosouthernpartsoftheSouthYellowSea.SpecialattentionshouldbepaidtothefavorablestructuralbeltsSYI1,SYI2,SYI3andSYI4inthesouthernbasinoftheSouthYellowSea,wheredetailedseismicexplorationordrillingshouldbecarriedout.AttentionshouldalsobegiventoMid-PaleozoicmarinestratainthemiddleupliftareaoftheSouthYellowSea.Keystrategiesthatcouldleadtoahydrocarbonexplorationbreakthroughareimprovingexplorationresolution,conductingdetailedstudiesoffinestructures,andaccuratelylocatingminorstructures.
简介:Althoughitiswellknownthatcoseismicgravitychangestakeplaceduringanearthquake,previousresearchhasnotyieldedconvincingevidencedemonstratingthatsignificantgravitychangesoccurbeforelargeearthquakes.Furthermore,evenifwesuspectthatgravitychangesoccurbeforelargeearthquakes,wehaveyettodemonstratehowtoconsistentlyobservethesechangesforusefulearthquakeforecastthatwouldbringbenefitstosociety.Weanalyzedgroundgravitysurveydataobtainedin1998,2000,2002,and2005atstationsoftheCrustalMovementObservationNetworkofChina(CMONOC)andexaminedgravitychangesbe-foretheoccurrenceofninelarge(Ms≥6.8)earthquakesthatrupturedwithinornearmainlandChinaandTaiwanfromNovember2001toAugust2008.Resultsfromthisanalysisshowthatsignificantgravitychangesoccurredacrossalargeregionbeforeeachoftheseninelargeearthquakes,andthesechangesweredetectedbyrepeatedgroundgravitysurveysthroughCMONOC.Althoughthesegravitychangesweresignificant,moreresearchisneededtoinvestigatewhetherthesegravitychangescouldbeviewedasprecursorsoflargeearthquakes.Limitationsanduncertaintiesinthedataincludesparsenessofthegravitymonitoringnetwork,longtimeintervalsbetweenconsecutivegravitysurveys,inevitablemeasurementerrors,hydrologicaleffectsongravity,andeffectsofverticalcrustalmovementsongravity.Basedontheseobservations,wemakeseveralrecommendationsaboutpossiblefuturedirec-tionsinearthquake-relatedresearchusinggravitymonitoringdata.
简介:Thenonlinearcapillary-gravitywaveproducedbyaverticallyoscillatingplate,inwhichthecontact-anglemodelisconsidered,isstudiedbyuseoftheBoundaryIntegralEquationMethod(BIEM).Thepresentnumericalexperimentshowsthatthecodeisrobustandefficientformodelingthegenerationandpropagationofcapillary-gravitywaves.Itisfoundthatthewaveheightsofstationaryperiodicnonlinearwavesradiatedawayfromtheplatearedependentontheparametersinvolvedinthecontact-an-glemodel.Theeffectofthecontact-anglehysteresisandthenonlinearityofcapillary-gravitywavesonthewaveprofileisdiscussedinthepaper.
简介:TheMS7.0JiuzhaigouearthquakeoccurredonAugust8,2017.TheearthquakeoccurredinthevicinityoftheTazangfault,theMinjiangfaultandtheHuyafault,wherethefocalmechanismisofthestrikesliptype.Thestaticanddynamicanomaliesofthegravityfieldcanprovideimportantphysicalfieldinformationforstudyingthestructuralpropertiesofdeepcrust.Multi-scaledecompositiontechniquesareusedtoseparateBouguergravityatdifferentdepthsandgivesomeexplanationtogravityvariationsatdifferenttimespacescales.Theresultsindicatethatthewaveletmulti-scaleresultsoftheEGM2008modelandthemeasuredgravitydataareconsistent.Throughcomparativeanalysis,itisfoundthattheJiuzhaigouearthquakeoccurredinthestressenhancedregion.Thevariationofgravityfieldatdifferenttimescaleshasacertainscientificsignificanceforfurtherunderstandingpotentialearthquakerisktrend.