简介：TheChi-Chiearthquakein1999causeddisastrouslandslides,whichtriggerednumerousdebrisflowsandkilledhundredsofpeople.Acriticalrainfallintensitylineforeachdebris-flowstreamisstudiedtopreventsuchadisaster.However,settingrainfalllinesfromincompletedataisdifficult,sothisstudyconsideredeightcriticalfactorstogroupstreams,suchthatstreamswithinaclusterhavesimilarrainfalllines.Ageneticalgorithmisappliedtogroup377debris-flowstreamsselectedfromthecenterofanareaaffectedbytheChi-Chiearthquake.Thesestreamsaregroupedintosevenclusterswithdifferentcharacteristics.Theresultsrevealthattheproposedmethodeffectivelygroupsdebris-flowstreams.

简介：Thehorizontalaccuracyoftopographicdatarepresentedbydigitalelevationmodel(DEM)resolutionbringsaboutuncertaintiesinlandscapeprocessmodelingwithrasterGIS.Thispaperpresentsastudyontheeffectoftopographicvariabilityoncell-basedempiricalestimationofsoillossandsedimenttransport.AnoriginalDEMof10mresolutionforacasewatershedwasre-sampledtothreerealizationsofhighergridsizesforacomparativeexamination.EquationsbasedontheUSLEareappliedtothewatershedtocalculatesoillossfromeachcellandtotalsedimenttransporttostreams.ThestudyfoundthatthecalculatedtotalsoillossfromthewatersheddecreaseswiththeincreasingDEMresolutionwithalinearcorrelationasspatialvariabilityisreducedbycellaggregation.TheUSLEtopographicfactors(LS)extractedfromappliedDEMsrepresentspatialvariability,anddeterminetheestimationsasshowninthemodelingresults.ThecommonlyusedUSGS30mDEMappearstobeabletoreflectessentialspatialvariabilityandsuitablefortheempiricalestimation.TheappropriatenessofaDEMresolutionisdependentuponspecificlandscapecharacteristics,appliedmodelanditsparameterization.ThisworkattemptstoprovideageneralframeworkfortheresearchintheDEM-basedempiricalmodeling.

简介：Localscourmayoccurwhenahydraulicstructureispositionedinachannelwithanerodiblebed.Herewithinvestigatedexperimentallyaretheerosionandflowpatternduetoawaterjetpassingoverachannelbedattheasymptotic(final)state.Thedevelopmentofthescourhole,itsmaximumscourdepthandlength,arerecordedandcomparedwithavailablescour-depthrelations.Twosetsofexperiments(seeTable1)werecarriedout.Set1(3runs)wasconcernedwithmeasuringtheverticalinstantaneousvelocitydistributioninthescourhole.Thescourholeattheasymptotic(final)state,t≈100[h]wasinvestigated.Set2(5runs)wasconcernedwithstudyingthephysicsofscouring.Thescourholeataboutmid-state,t≈0.5[h],wasinvestigated;subsequentlythescour-holedepthwaslinearlyextendedonthesemi-logscaleto72[h];novelocitymeasurementswereperformed.Thepresentdataareputincontextwithsome(popular)existingrelations;recommendedisamodificationofsomeoftheserelations.

简介：Laboratoryexperimentsonlongitudinaldispersioninclear-waterandsediment-ladenopenchannelflowsarereported.Datafromtheseexperimentsandthoseavailablefrompreviousstudiesindicatethatthesuspendedsedimentpresentintheflowaffectsthelongitudinaldispersionprocess.Theobservedvelocitydistributionsoverthedepthofsediment-ladenflowsindicatethatthevelocitydeviatesfromthemeanvelocitymoreinsediment-ladenflowsthaninclear-waterflows.Thevelocitydistributionsoverthecrosssectionandsecondaryflowinthechannelarealsoexpectedtobealteredduetothepresenceofsuspendedsedimentsintheflow.Forthesereasons,moredispersionisfoundinsediment-ladenflowsthanincorrespondingclear-waterflows.Apredictorforthedispersioncoefficientinsediment-ladenflowsisproposed.

简介：In1997,theTZ-162wellinTazhongareaoftheTarimbasinhitthelowerPaleozoicdolomitereservoiratadepthof5,900m.Thedistributionofthedolomitereservoir,however,wasverydifficulttodelineateduetothecomplexsurfaceconditionsandpoorseismicproperties.High-precisiontransientelectromagneticsounding(TEM)wasconductedandgoodresultsobtainedinthisarea.Thispaperdiscussedtheprinciple,dataprocessingandinterpretationofthismethod.Theresultsofstudyingthedolomitereservoirsdemonstratedtheeffectivenessofthemethodinstudyingthelow-resistancedolomitereservoirsinthehigh-resistancecarbonates.Thismethodshouldbeaneffectiveonetostudyreservoirsinareaswithsimilarphysicalpropertiesaswell.

简介：TheCarboniferousandPre-CarboniferousformationsinLudong,Zhungarbasin,containfavorableoil/gasreservoirs.TheCarboniferousformations,however,arecomplexinstructureandexhibitlateralvariationsinlithology.SeismicreflectionsfromPre-Triassicformationsarepoorandthevolcanicreservoirsareverydifficulttoidentify.Theanalysisofphysicalpropertiesconcludedthatthemajortargetsinthisregion,i.e.,thetopoftheJurassicandCarboniferousformations,providedistinctdensityinterfaces.Thebasic,intermediateandacidvolcanicrockswerealsodifferentindensity,resultingindistinguishablegravityanomalies.Thedifferencesinmagnetisminthisregionexistednotonlybetweenthevolcanicrocksandclasticsedimentaryrocksbutalsoamongvolcanicrockswithdifferentcompositions.Allformationsandvolcanicrocksofdifferentlithologiespresentedhighandlowresistanceinterbeds,whicharecharacterizedbyregionaltrends.Themodelingstudydemonstratedthatnon-seismicintegratedgeophysicaltechniquesshouldbefeasibleinthisregion,especiaUythehigh-precisiongravity/magneticmethodscombinedwithlongoffsettransientelectromagneticsounding.

简介：Upwellingcoastalsystemscanbeusedtounderstandhowdissolvedoxygenandbiologicalproductivitycontroltheaccumulationofredox-sensitivemetalsinmarinesediments.Thealuminium(Al),cadmium(Cd),iron(Fe),nickel(Ni),molybdenum(Mo),vanadium(V),totalorganiccarbon(TOC),totalnitrogen(TN)andtotalsulfur(TS)contentsinsurficialsedimentcollectedfromdifferentwaterdepths(30,70,and120m)inthreenorthernChileanbaysinfluencedbycoastalupwellingandoxygenminimumzones(OMZs)weremeasured.Principalcomponentanalysis(PCA),clusteranalysis,andSpearman'srankcorrelationwereusedtoidentifythemechanismsresponsiblefortheredox-sensitivemetalaccumulation.Thecontentofredox-sensitivemetalsandorganiccomponentsinsedimentincreasedwithincreasingwatercolumndepth,whereaslithogenicmetalsdecreased.IntheMejillonesdelSurandCalderabays,theenrichmentfactorsoftheredox-sensitivemetalsshowedenrichmentforallmetalswithdepth.TheCdandVenrichmentsaremainlytheproductofbiogenicflowtotheseabed,andtheMoandNienrichmentsareduetopreservationunderlowsubsurfaceoxygenconditions.Sulfatereductionisnotanimportantmechanismintheaccumulationofredox-sensitivemetalsinthesedimentofthethreebays.ThePCAshowedthatthebehaviorsoftheredox-sensitivemetalsandorganiccomponentsreflectdifferencesintheeffectsoftheOMZinsedimentalongthecoastofnorthernChile,withamoreintenseOMZinMejillonesdelSurbayandweakerOMZsinCalderaandInglesabays.However,thehighdegreeofenrichmentinredox-sensitivemetalsinCalderaBaycanbeattributedtotheintenseactivityoftheminingindustrynearthebay,asituationthatproducesgeochemicalbehaviorsimilartothatobservedinMejillonesdelSurBay.

简介：Soilsusceptibilitytodetachmentandtransportsub-processesoferosionisgenerallycontroledbytheaggregatebreakdownmechanism.Measuringparticlesizeandaggregationtotheestimateerodibilitypotentialofsoilsisimportantundererosiverainfallconditions.TheAggregateSizeDistribution(ASD)isoneofthemostimportantdeterminantsofsoilstructurealongwithsoilorganicmattercontentfordescribingtheefficiencyofapplied,sustainablemanagementstrategies.Thisstudyaimedtocomparetheperformancesofthreedifferentaggregatesizedistributionmodelstopredictthecharacteristicaggregatesizeparameter(mediandiameter,D50)forerodedsedimentfrominterrillerosionprocessesofRain-SplashTransport(RST)andRaindropImpactedFlowTransport(RIFT).TheASDsof1143collectedsedimentsamplesfromtheRSTandRIFTprocessesweremeasuredandmodeledbytheLog-normal,Fractal,andWeibullapproaches.TheD50value,asacharacteristicparameterforaggregatesizedistributions,derivedfromthecumulativeASDcurvewascomparedforsoilsfromdifferentlandusetypesanddifferentslopeandrainfallintensityconditions.TheperformanceofeachmodelwasevaluatedusingtheMeanSquareError(MSE)andCoefficientofDetermination(R^2).TheWeibullapproachwasthemostaccuratemodelshowingthebestfitwiththelowestMSEvalues(0.0002≤MSE≤0.0048)andhavingthegreatestR2values(0.936≤R^2≤0.998)whencomparedwiththeLog-normalandFractalmodels.Herewith,forsemi-aridlanduseandsoil,specificshapeandscaleparametersfortheWeibulldistribution,therespectiveASDsweresuccessfullyre-generatedformodelingtheerodedsedimentofthesimulatedRSTandRIFTinterillprocesses.

简介：Researchonin-channelsandminingisimperativeasitmayhaveasignificantimpactonchannelmorphology.Followingthisquesttoquantitativelycomprehendthephenomenon,experimentalstudiesweredonetoinvestigatethedynamiccharacteristicsofthemigrationofaminingpit.Theevaluationofthemigrationrateofaminingpitinaphysicalscalemodelhasfoundariseinthemigrationrateofthepit'supstreamedgewithincreasingdischarge.Awaveletanalysisappliedforanalyzingscale-dependentmigrationofthebedprofileofaminingpitalsorevealedsimilarfindings.Additionally,thewaveletanalysisexaminedthelength-scaledependentmigrationofaminingpitandadecreaseinthemigrationratehasbeenobservedwithanincreaseinthelengthscale.Theplanformofapit(length-to-widthratio)governstheerosionanddepositionprocessesaroundthepit.Bothphysicalandstatisticalapproachesshowanincreaseinthemigrationratewithanincreaseinthelength-to-widthratioofthepit.Anempiricalformulationhasbeendevelopedforcalculatingthemigrationrateoftheupstreamedgeofaminingpitbasedonpitgeometry(length-to-widthratio),averageflowvelocity,andcriticalshearstressofthebedmaterial.Theresultsalsoshowahigherbedloadtransportrateinthechannelsubjectedtominingascomparedtoaplainbedchannel.

简介：Determinationofsedimentstabilityinthefieldischallengingbecausebedshearstress(BSS),adeterminingfactorofsedimenterosion,can’teasilybedirectlymeasured.Totacklethischallengeandreliablyassesssedimenterodibilityinafastflowingriver,astandaloneunderwatercamerasystemandanewinsituflume(ISF)weredevelopedandappliedinthisstudy.ThecamerasystemwasusedtorecordsedimentmovementandthenewISFwasusedformeasuringcriticalbottomshearstress(CBSS).Thecameracanbedeployedaloneinwatertorecordvideosortakepictureswithlightemittingdiode(LED)lightingandflexibleschedulesettings.TheISFisbasedontheconceptthattheamountofforceneededtoerodethesameparticleunderdifferentflowconditionsshouldbesimilar.TwohighresolutionAcousticDopplerCurrentProfilers(ADCP)alsoweredeployedinthefieldtocollectvelocity-depthprofileswhichareusedbyconventionalmethodstocalculateBSSwiththelawofthewall.ThesedimenterodibilitywasthenassessedbasedonthecomparisonbetweentheobtainedCBSSandBSSandthenfurtherverifiedwiththerecordedobservationsfromthedeployedcamera.Theresultsrevealthatthewidelyusedconventionalmethodcanproducelargeuncertaintiesandisnotadequatetoprovidemeaningfulconclusionundertheseconditions.

简介：Theeffectoffullysubmergedbouldersontheflowstructureinchannelshasbeenstudiedbysomeresearchers.However,manynaturalstreamshavebedmaterialwithbouldersthatarenotfullysubmergedunderwater.Inmanynaturalstreams,boulderscoverbetween1%and10%oftheareaofthestreamreach.Theeffectofnon-submergedbouldersonthevelocityprofileandflowcharacteristicsisveryimportantforassessingriverbeddeformation.Theobjectivesofthispaperaretofindthepatternofvelocitydistributionaroundanon-submergedboulderandtocompareitwiththeclassicalstudiesonflowresistanceandReynoldsstressdistributioninopenchannels.Also,byconsideringthevariationintheReynoldsstressdistributionatdifferentlocationsaroundanon-submergedboulder,theeffectofanon-submergedboulderontheestimationofshearvelocityandresistancetoflowhasbeeninvestigated.Resultsindicatesthatinsidethescourholecausedbyanon-submergedboulderinarivervelocitydistributionsareirregular.However,velocitydistributionsareregularoutsidethescourhole.ThepresenceofthebouldercausesaconsiderabledeviationoftheReynoldsshearstressfromtheclassicdistribution,showinganon-specificdistributionwithnegativevalues.TheclassicalmethodsforcalculatingshearvelocityarenotsuitablebecausethesemethodsdonotgivedetailedvelocityandReynoldsstressdistributionsinnaturalriverswithalotofboulders.Thus,theeffectofanon-submergedboulderontheestimationoftheresistancetoflowbyconsideringthevariationsinvelocityandReynoldsstressdistributionsatdifferentlocationsaroundanon-submergedboulderisimportantandneedstobestudiedinanaturalriverinsteadofjustinlaboratoryflumes.ThenegativevaluesinReynoldsstressdistributionaroundaboulderindicatethattheclassicalmethodsareunabletopredictresistancetoflow,andalsoshowstrongturbulenceinsidethescourholewherethecomplexflowconditionspresentambi

简介：MostofthestudiesonArtificialNeuralNetwork(ANN)modelsremainrestrictedtosmallerriversandcatchments.Inthispaper,anattempthasbeenmadetocorrelatevariabilityofsedimentloadswithrainfallandrunoffthroughtheapplicationoftheBackPropagationNeuralNetwork(BPNN)algorithmforalargetropicalriver.ThealgorithmandsimulationaredonethroughMATLABenvironment.Themethodologycomprisedofacollectionofdataonrainfall,waterdischarge,andsedimentdischargefortheNarmadaRiveratvariouslocations(alongwithtimevariables)andapplicationtodevelopathreelayerBPNNmodelforthepredictionofsedimentdischarges.Fortrainingandvalidationpurposesasetof549datapointsforthemonsoon(16June-15November)periodofthreeconsecutiveyears(1996–1998)wasused.Fortestingpurposes,theBPNNmodelwasfurthertrainedusingasetof732datapointsofmonsoonseasonoffouryears(2006–07to2009–10)atninestations.Themodelwastestedbypredictingdailysedimentloadforthemonsoonseasonoftheyear2010–11.ToevaluatetheperformanceoftheBPNNmodel,errorswerecalculatedbycomparingtheactualandpredictedloads.Thevalidationandtestingresultsobtainedatalltheselocationsaretabulatedanddiscussed.Resultsobtainedfromthemodelapplicationarerobustandencouragingnotonlyforthesub-basinsbutalsofortheentirebasin.Theseresultssuggestthattheproposedmodeliscapableofpredictingthedailysedimentloadevenatdownstreamlocations,whichshownonlinearityinthetransportationprocess.Overall,theproposedmodelwithfurthertrainingmightbeusefulinthepredictionofsedimentdischargesforlargeriverbasins.

简介：Sincelocalscouratbridgepiersinriversandestuariesisamajorcauseofbridgefailure,estimationofthemaximumlocalscourdepthisofgreatimportancetohydraulicandcoastalengineers.Althoughnumerousstudiesthatfocusonscour-depthpredictionhavebeendoneandpublished,understandingoftheflowandturbulencecharacteristicsofthehorseshoevortexthatdrivesthescourmechanisminadevelopingscourholestillisimmature.Thisstudyaimstoquantifythedetailedturbulentflowfieldinadevelopingclear-waterscourholeatacircularpierusingParticleImageVelocimetry(PIV).Thedistributionsofvelocityfields,turbulenceintensities,andReynoldsshearstressesofthehorseshoevortexthatforminfrontofthepieratdifferentscourstages(t=0,0.5,1,12,24,and48h)arepresentedinthispaper.Duringscourdevelopment,thehorseshoevortexsystemwasfoundtoevolvefromoneinitiallysmallvortextothreevortices.Thestrengthandsizeofthemainvortexarefoundtoincreasewithincreasingscourdepth.TheregionsofboththemaximumturbulenceintensityandReynoldsshearstressarefoundtoformatalocationupstreamofthemainvortex,wherethelargeturbulenteddieshavethehighestpossibilityofoccurrence.Resultsfromthisstudynotonlyprovidenewinsightintothecomplexflow-sedimentinteractionatbridgepiers,butalsoprovidevaluableexperimentaldatabasesforadvancednumericalsimulations.

简介：Thispapersummarizesthelatestdevelopments,futureprospects,andproposedcountermeasuresofreservoirsedimentationandchannelscourdownstreamoftheThreeGorgesReservoir(TGR)ontheYangtzeRiverinChina.Threekeyresultshavebeenfound.(1)TheincomingsedimentloadtotheTGRhasbeensignificantlylowerthanexpected.(2)TheaccumulatedvolumeofsedimentdepositionintheTGRissmallerthanexpectedbecausetheoverallsedimentdeliveryratioisrelativelylow,andthedepositioninthenear-damareaoftheTGRisstilldeveloping.(3)RiverbedscourintheriverreachesdownstreamoftheGezhoubaDamisstilloccurringandchannelscourhasextendedtoreachesasfardownstreamastheHukoureach.Significantly,sedimentationoftheTGRislessproblematicthanexpectedsincethestartofoperationoftheTGRontheonehand;ontheotherhand,thepossibleincreasesinsedimentrisksfromdependenceonupstreamsedimentcontrol,depositioninthereservoir,andscouralongmiddleYangtzeRivershouldbepaidmoreattention.(1)SedimenttrappedbydamsbuiltalongtheupperYangtzeRiverandbilliontonsofloosematerialsonunstableslopesproducedbytheWenchuanEarthquakecouldbenewsedimentsourcesfortheupperYangtzeRiver.Moreseriously,possiblereleaseofthissedimentintotheupperYangtzeRiverduetonewearthquakesorextremeclimateeventscouldoverwhelmtheriversystem,andproducecatastrophicconsequences.(2)IncreasingsedimentdepositionintheTGRisharmfultothesafetyandefficiencyofprojectoperationandnavigation.(3)ThedrasticscouralongthemiddleYangtzeRiverhasintensifiedthedown-cuttingoftheriverbedanderosionofrevetment,ithasalreadyledtoincreasingrisktofloodcontrolstructuresandecologicalsafety.ItissuggestedtocontinuetheFieldObservationProgram,toinitiateresearchprogramsandtofocusonrisksofsedimentation.

简介：Therelationbetweenthewaterdischarge(Q)andsuspendedsedimentconcentration(SSC)oftheRiverRamgangaatBareilly,UttarPradesh,intheHimalayas,hasbeenmodeledusingArtificialNeuralNetworks(ANNs).Thecurrentstudyvalidatesthepracticalcapabilityandusefulnessofthistoolforsimulatingcomplexnonlinear,realworld,riversystemprocessesintheHimalayanscenario.ThemodelingapproachisbasedonthetimeseriesdatacollectedfromJanuarytoDecember(2008-2010)forQandSSC.ThreeANNs(T1-T3)withdifferentnetworkconfigurationshavebeendevelopedandtrainedusingtheLevenbergMarquardtBackPropagationAlgorithmintheMatlabroutines.Networkswereoptimizedusingtheenumerationtechnique,and,finally,thebestnetworkisusedtopredicttheSSCvaluesfortheyear2011.ThevaluesthusobtainedthroughtheANNmodelarecomparedwiththeobservedvaluesofSSC.Thecoefficientofdetermination(R2),fortheoptimalnetworkwasfoundtobe0.99.ThestudynotonlyprovidesinsightintoANNmodelingintheHimalayanriverscenario,butitalsofocusesontheimportanceofunderstandingariverbasinandthefactorsthataffecttheSSC,beforeattemptingtomodelit.Despitethetemporalvariationsinthestudyarea,itispossibletomodelandsuccessfullypredicttheSSCvalueswithverysimplisticANNmodels.

简介：Arobustmethodforcharacterizingthemineralogyofsuspendedsedimentincontinentalriversisintroduced.Itencompasses3steps:thefiltrationofafewmillilitersofwater,measurementsofX-rayenergydispersivespectrausingScanningElectronMicroscopy(SEM),androbustmachinelearningtoolsofclassification.ThemethodisappliedtosuspendedparticlescollectedfromvariousAmazonianrivers.Atotalofmorethan204,000particleswereanalyzedbySEM-EDXS(EnergyDispersiveX-raySpectroscopy),i.e.about15,700particlespersamplingstation,whichleadtotheidentificationof15distinctgroupsofmineralogicalphases.ThesizedistributionofparticlescollectedonthefilterswasderivedfromtheSEMmicrographstakeninthebackscatteredelectronimagingmodeandanalyzedwithImageJfreeware.Thedeterminationofthemainmineralogicalgroupscomposingthebulksedimentassociatedwithphysicalparameterssuchasparticlesizedistributionoraspectratioallowsaprecisecharacterizationoftheloadoftheterrigenousparticlesinriversorlakes.InthecaseoftheAmazonianriversinvestigated,theresultsshowthattheidentifiedmineralogiesareconsistentwithpreviousstudiesaswellasbetweenthedifferentsamplescollected.Themethodenabledtheevolutionofgrainsizedistributionfromfinetocoarsematerialtobedescribedinthewatercolumn.Implicationsabouthydrodynamicsortingofmineralparticlesinthewatercolumnarealsobrieflydiscussed.Theproposedmethodappearswellsuitedforintensiveroutinemonitoringofsuspendedsedimentinriversystems.

简介：Theattenuationfactororqualityfactor(Q-factororQ)hasbeenusedtomeasuretheenergyattenuationofseismicwavespropagatinginundergroundmedia.ManymethodsareusedtoestimatetheQ-factor.WeproposeamethodtocalculatetheQ-factorbasedontheprestackQ-factorinversionandthegeneralizedS-transform.TheproposedmethodspecifiesastandardprimarywaveletandcalculatesthecumulativeQ-factors;then,itfindstheinterlaminarQ-factorsusingtherelationbetweenQandoffset(QVO)andtheDixformula.TheproposedmethodisalternativetomethodsthatcalculateinterlaminarQ-factorsafterhorizonpicking.Becausethefrequencyspectrumofeachhorizoncanbeextractedcontinuouslyona2Dtime–frequencyspectrum,themethodiscalledthecontinuousspectralratioslope(CSRS)method.ComparedwiththeotherQ-inversionmethods,themethodoffersnearlyeffortlesscomputationsandstability,andhasmathematicalandphysicalsignificance.WeusenumericalmodelingtoverifythefeasibilityofthemethodandapplyittorealdatafromanoilfieldinAhdeb,Iraq.TheresultssuggestthattheresolutionandspatialstabilityoftheQ-profileareoptimalandcontainabundantinterlaminarinformationthatisextremelyhelpfulinmakinglithologyandfluidpredictions.

简介：JointPP–PSinversionoffersbetteraccuracyandresolutionthanconventionalP-waveinversion.P-andS-waveelasticmodulideterminedthroughdatainversionsarekeyparametersforreservoirevaluationandfluidcharacterization.Inthispaper,startingwiththeexactZoeppritzequationthatrelatesP-andS-wavemoduli,acoefficientthatdescribesthereflectionsofP-andconvertedwavesisestablished.Thismethodeffectivelyavoidserrorintroducedbyapproximationsorindirectcalculations,thusimprovingtheaccuracyoftheinversionresults.Consideringthattheinversionproblemisill-posedandthattheforwardoperatorisnonlinear,priorconstraintsonthemodelparametersandmodifiedlow-frequencyconstraintsarealsointroducedtotheobjectivefunctiontomaketheproblemmoretractable.Thismodifiedobjectivefunctionissolvedovermanyiterationstocontinuouslyoptimizethebackgroundvaluesofthevelocityratio,whichincreasesthestabilityoftheinversionprocess.TestsofvariousmodelsshowthatthemethodeffectivelyimprovestheaccuracyandstabilityofextractingPandS-wavemodulifromunderdetermineddata.Thismethodcanbeappliedtoprovideinferencesforreservoirexplorationandfluidextraction.

简介：MostcurrentprestackAVAjointinversionmethodsarebasedontheexactZoeppritzequationanditsvariousapproximations.However,theseequationsonlyreflecttherelationbetweenreflectioncoefficients,incidenceangles,andelasticparametersoneithersideoftheinterface,whichmeansthatwave-propagationeffects,suchassphericalspreading,attenuation,transmissionloss,multiples,andeventmismatchingofP-andS-waves,arenotconsideredandcannotaccuratelydescribethetruepropagationcharacteristicsofseismicwaves.ConventionalAVAinversionmethodsrequirethatthesewave-propagationeffectshavebeenfullycorrectedorattenuatedbeforeinversionbuttheserequirementscanhardlybesatisfiedinpractice.Usingaone-dimensional(1D)earthmodel,thereflectivitymethodcansimulatethefullwavefieldresponseofseismicwaves.Therefore,weproposeanonlinearmulticomponentprestackAVAjointinversionmethodbasedonthevectorizedreflectivitymethod,whichusesafastnondominatedsortinggeneticalgorithm(NSGAII)tooptimizethenonlinearmultiobjectivefunctiontoestimatemultipleparameters,suchasP-wavevelocity,S-wavevelocity,anddensity.Thisapproachisrobustbecauseitcansimultaneouslycopewithmorethanoneobjectivefunctionwithoutintroducingweightcoefficients.Modeltestsprovetheeffectivenessoftheproposedinversionmethod.Basedontheinversionresults,wefindthatthenonlinearprestackAVAjointinversionusingthereflectivitymethodyieldsmoreaccurateinversionresultsthantheinversionbyusingtheexactZoeppritzequationwhenthewave-propagationeffectsoftransmissionlossandinternalmultiplesarenotcompletelycorrected.

简介：Inmarineseismicexploration,ocean-bottomcabletechniquesaccuratelyrecordthemulticomponentseismicwavefield;however,theseismicwavepropagationinfluid–solidmediacannotbesimulatedbyasinglewaveequation.Inaddition,whentheseabedinterfaceisirregular,traditionalfinite-differenceschemescannotsimulatetheseismicwavepropagationacrosstheirregularseabedinterface.Therefore,anacoustic–elasticforwardmodelingandvector-basedP-andS-waveseparationmethodisproposed.Inthismethod,wedividethefluid–solidelasticmediawithirregularinterfaceintoorthogonalgridsandmaptheirregularinterfaceintheCartesiancoordinatessystemintoahorizontalinterfaceinthecurvilinearcoordinatessystemofthecomputationaldomainusingcoordinatestransformation.Theacousticandelasticwaveequationsinthecurvilinearcoordinatessystemareappliedtothefluidandsolidmedium,respectively.Attheirregularinterface,thetwoequationsarecombinedintoanacoustic–elasticequationinthecurvilinearcoordinatessystem.Wenextintroduceafullstaggered-gridschemetoimprovethestabilityofthenumericalsimulation.Thus,separateP-andS-waveequationsinthecurvilinearcoordinatessystemarederivedtorealizetheP-andS-waveseparationmethod.