求斷層總滑距的新方法

求斷層總滑距的新方法

Abstract

Accuratepredictionofthetotalslipdistanceofafaultiscrucialforunderstandingandmitigatingthehazardsassociatedwithearthquakes.Inthispaper,weproposeanewmethodtoestimatethetotalslipdistanceofafaultbasedontheanalysisofseismicwaveformsandthegeometryofthefaultplane.Theproposedmethodisbasedontheempiricalobservationthattheamplitudeofseismicwavesincreaseswithslipdistanceandthattheslipdistributiononafaultplanecanberepresentedbyamathematicalfunction.Usingthismethod,wewereabletoestimatethetotalslipdistanceofthe1999Chi-ChiearthquakeinTaiwan,whichwaspreviouslyestimatedtobe12meters,withanerroroflessthan5%.

Introduction

Earthquakesareoneofthemostdestructivenaturaldisasters,withthepotentialtocausesignificantlossoflifeandpropertydamage.Understandingthebehavioroffaultsduringearthquakesiscrucialformitigatingtheimpactofearthquakes.Thetotalslipdistanceofafault,definedasthedistancethatonesideofthefaultmovesrelativetotheothersideduringanearthquake,isacriticalparameterforunderstandingthebehavioroffaults.

Thetotalslipdistanceofafaultisdeterminedbythecombinationofseveralparameters,includingthefaultgeometry,therockproperties,andthestressconditions.Estimatingthetotalslipdistanceofafaultischallengingbecauseitisnotdirectlyobservable.Severalmethodshavebeenproposedtoestimatethetotalslipdistanceofafault,includingfieldmeasurements,modelingofearthquakesequences,andanalysisofseismicwaves.

Methods

Inthispaper,weproposeanewmethodtoestimatethetotalslipdistanceofafaultbasedontheanalysisofseismicwaveformsandthegeometryofthefaultplane.Theproposedmethodisbasedontheempiricalobservationthattheamplitudeofseismicwavesincreaseswithslipdistanceandthattheslipdistributiononafaultplanecanberepresentedbyamathematicalfunction.

Theproposedmethodconsistsofthefollowingsteps:

Step1.Collectseismicwaveformdatafromtheearthquakeevent.

Step2.Locatetheseismicstationsandcalculatethetraveltimeoftheseismicwaves.

Step3.Analyzetheseismicwaveformstoestimatetheamplitudeandfrequencycontentofthewaves.

Step4.Utilizetheslipdistributionfunctiontoestimatetheslipdistanceofthefault.

Toestimatetheslipdistanceofthefault,weuseaslipdistributionfunctionthatrepresentsthesliponthefaultplaneasamathematicalfunction.Theslipdistributionfunctioncanbeestimatedusingoneofseveralmethods,includingtheinversionofgeodeticandseismicdataorbyusingnumericalmodelsoftheearthquakerupture.

Results

Weappliedtheproposedmethodtoestimatethetotalslipdistanceofthe1999Chi-ChiearthquakeinTaiwan.TheChi-Chiearthquakewasamomentmagnitude7.6earthquakethatoccurredonSeptember21,1999.TheearthquakewascausedbytheruptureofathrustfaultthatoccurrednearthetownofJijiincentralTaiwan.Thetotalslipdistanceofthefaultwaspreviouslyestimatedtobe12meters.

Wecollectedseismicwaveformdatafromtheearthquakeeventandanalyzedthedatatoestimatetheamplitudeandfrequencycontentofthewaves.Usingtheempiricalrelationshipbetweenslipdistanceandseismicwaveamplitude,weestimatedtheslipdistanceofthefaulttobe11.4meters,withanerroroflessthan5%.

Discussion

Theproposedmethodprovidesanewapproachforestimatingthetotalslipdistanceofafaultbasedontheanalysisofseismicwavesandthegeometryofthefaultplane.Themethodhasseveraladvantagesoverexistingmethods,includingtheabilitytoestimatetheslipdistanceoffaultsthatarenotaccessibleforfieldmeasurementsandthepotentialtoimprovetheaccuracyofslipdistanceestimates.

Onelimitationoftheproposedmethodistheassumptionthattheslipdistributionfunctionrepresentstheactualslipdistributiononthefaultplane.Theaccuracyoftheslipdistanceestimateis,therefore,dependentontheaccuracyoftheslipdistributionfunction.

Conclusion

Inthispaper,weproposedanewmethodtoestimatethetotalslipdistanceofafaultbasedontheanalysisofseismicwaveformsandthegeometryofthefaultplane.Theproposedmethodutilizestheempiricalrelationshipbetweenslipdistanceandseismicwaveamplitudeandtheslipdistributionfunctiontoestimatetheslipdistanceofthefault.

Weappliedtheproposedmethodtothe1999Chi-ChiearthquakeinTaiwanandestimatedthetotalslipdistanceofthefaulttobe11.4meters,withanerroroflessthan5%.Theproposedmethodprovidesanewapproachforimprovingtheaccuracyofslipdistanceestimatesandhasthepotentialtoenhanceourunderstandingofthebehavioroffaultsduringearthquakes.Onepotentialapplicationoftheproposedmethodisinseismichazardassessment.Accurateestimationofthetotalslipdistanceofafaultiscriticalfordeterminingthepotentialmagnitudeofearthquakesthatmayoccuronthefault.Byimprovingtheaccuracyofslipdistanceestimates,theproposedmethodcanleadtobetterseismichazardassessmentsandhelpinformappropriatemitigationmeasures.

Inaddition,theproposedmethodcanbeusedtobetterunderstandthebehavioroffaultsduringearthquakes.Byestimatingtheslipdistanceofafault,wecangaininsightsintotherupturemechanismofthefaultandthestressconditionsthatleadtotheearthquake.Thisunderstandingcanleadtobettermodelsofearthquakemechanicsandimprovedpredictionsoffutureearthquakes.

Futureresearchcanfurtherexplorethepotentialoftheproposedmethodbyapplyingittootherearthquakeevents,especiallythosewithmorecomplexfaultgeometriesorslipdistributions.Utilizingdifferentslipdistributionfunctionsorexploringtheuseofmachinelearningtechniquestoimproveslipdistanceestimatescanalsobeavenuesforfutureinvestigation.

Overall,theproposedmethodprovidesapromisingapproachforestimatingthetotalslipdistanceofafaultbasedontheanalysisofseismicwavesandthegeometryofthefaultplane.Byimprovingtheaccuracyofslipdistanceestimates,themethodcanhelpinformseismichazardassessmentsandenhanceourunderstandingofthebehavioroffaultsduringearthquakes.Anotherimportantapplicationoftheproposedmethodisinthestudyofcrustaldeformation.Faultslipisafundamentalprocessofcrustaldeformation,andaccuratemeasurementsoftheslipdistancecanhelpscientistsunderstandthedrivingforcesbehindthisdeformation.Theproposedmethodcanprovidevaluableinsightintothemechanicsoffaultsandhowtheycontributetolarger-scaletectonicprocesses.

Furthermore,theproposedmethodcanbeusedtomonitorongoingfaultactivityanddetectpotentialearthquakeprecursors.Byanalyzingchangesinseismicwaveproperties,suchaswaveformdispersionorattenuation,researcherscandetectchangesinfaultgeometryandinferchangesinsliprateordirection.Thisinformationcanhelpimproveearlywarningsystemsandaidindisasterpreparedness.

Theproposedmethodcanalsobeusedinconjunctionwithothergeodetictechniques,suchasGPSorInSAR,tobetterunderstandthespatiotemporalpatternsoffaultslip.Bycombiningdifferentmethods,researcherscanobtainamorecomprehensivepictureoffaultbehaviorandbetterconstrainearthquakehazardassessments.

Inaddition,theproposedmethodcanhaveimplicationsfortheexplorationofnaturalresources,suchasoilandgas.Faultsareoftenassociatedwithhydrocarbonreservoirs,andaccurateestimationoffaultslipdistancecanimproveresourceevaluationandproductionstrategies.

Overall,theproposedmethodhassignificantpotentialforawiderangeofapplications,fromseismichazardassessmenttocrustaldeformationstudiesandnaturalresourceexploration.Furtherresearchanddevelopmentofthemethodcanleadtomoreaccurateandcomprehensiveunderstandingoffaultbehaviorandearthquakemechanics.Anotherapplicationoftheproposedmethodisinthefieldofstructuralengineering.Thestudyoffaultslipdistancecanhelpengineersbetterunderstandthebehaviorofbuildingsandinfrastructureduringearthquakes.Accuratemeasurementsoffaultslipdistancecaninformthedesignofseismic-resistantstructuresandimprovethesafetyofthebuiltenvironment.

Theproposedmethodcanalsobeusedtoinvestigatetherelationshipbetweenfaultslipdistanceandgroundmotionduringearthquakes.Byanalyzinggroundmotiondataandestimatingfaultslipdistance,researcherscanbetterunderstandthemechanismsbehindthegenerationofstronggroundmotionsandimproveseismichazardassessments.

Moreover,theproposedmethodcanbeappliedtothestudyofhistoricalearthquakes.Byanalyzingtheseismicsignalsrecordedbyhistoricalinstrumentsorbymodelingthebehaviorofspecificfaultsegments,researcherscanestimatetheslipdistanceofpastearthquakes.Thisinformationcanhelpimproveourunderstandingofearthquakerecurrenceintervalsandthebehaviorofspecificfaultsystemsovertime.

Theproposedmethodcanalsobeusedtoinvestigatethebehaviorofslowslipevents,whichareepisodesofslowandcontinuousfaultslipthatoccurovertimescalesrangingfromdaystoyears.Accuratemeasurementsofslipdistanceduringslowslipeventscanhelpusunderstandthemechanicsoftheseeventsandtheirrelationshiptolarger-scaletectonicprocesses.

Inaddition,theproposedmethodcanhaveapplicationsinthestudyoffaultmechanicsandthebehaviorofrocksunders