简介:Researchoftidaltriggeringofearthquakesinrecentyearsissystematicallyreviewed,focusingontherelationshipbetweenthephasesofthemoonandseismicactivity,earthquakestriggeredbytidalforcesanditscomponents,basedonthelargesamplestatisticstodiscussthetidaltriggeringofanearthquake.Therelationshipbetweenthephaseofthemoonandseismicactivityisapreliminarystudyoftidaltriggeringofearthquakes,andthemodulationratioisaquantitativedescriptionofit.Usingtheresolutionoftidalstresstostudyseismicactivityisawaytorevealtherelationshipbetweenthetidesandearthquakesfromthemechanicspointofview.Largesamplestatisticsisanotherwaytostudytherelationshipbetweenthetidalandearthquakefromtheviewofstatistics.Inmanystatisticalmethods,Schuster'stestisusedmorewidely,whichtakesmanyfactorsintoaccount,suchasfocalmechanism,tidalstress,andstatisticalteststoquantitativelyanalyzethetidaltriggeringeffectonearthquakes.
简介:Thermalconvectiveprecipitation(TCP)oftenoccursovermainlandChinainsummerwhentheareaisdominatedbythewesternPacificsubtropicalhigh(WPSH).ItiswellknownthattheWPSHoftenbringsaboutlargescalesubsidence,thenwhycoulddeepmoistconvectionoccurandwheredoesthewatervaporcomefrom?Inthispaper,adeepconvectiveprecipitationcasethathappenedon2August2003isstudiedinordertoaddressthesetwoquestions.First,thecharacteristicsoftheTCPeventareanalyzedusingtheTropicalRainfallMeasuringMission(TRMM)satellitedata,automaticweatherstationobservations,andthedatafromtheUSNationalCentersforEnvironmentalPrediction(NCEP).Second,watervaporsourcesareidentifiedthroughexaminingsurfaceevaporation,watervaporadvection,andwatervaporfluxdivergencecalculatedbyusingaregionallyaveragedwatervaporbudgetequation.Furthermore,usinganAdvancedRegionalEta-coordinateModel(AREM),contributionsofsensibleandlatentheatfluxestotheTCParecomparedthroughfoursensitivityexperiments.TheresultsshowthatintheregionscontrolledbytheWPSH,surfacetemperaturerisesrapidlyaftersunrise.Uponreceivingenoughsensibleheat,theairgoesupandleadstoconvergenceintheloweratmosphere.Thenthewatervaporassembledfromthesurroundingsandthegroundsurfaceistransportedtotheupperlevels,andafavorableenvironmentfortheTCPforms.Amodeldatadiagnosisindicatesthatabouthalfofprecipitablewatercomesfromtheconvergenceofhorizontalfluxesofwatervapor,andtheotherhalffromsurfaceevaporation,whilelittleisfromadvection.AdditionalsensitivityexperimentsprovethatbothsensibleandlatentheatingareessentialfortheonsetoftheTCP.Thesensibleheatfluxtriggersthermodynamicascendingmotion,andthelatentheatfluxprovideswatervapor,butthecontributiontoTCPfromthelatterisalittlesmallerthanthatfromtheformer.
简介:TheresultsobtainedusingthegroupmodelofearthquakesgeneratedintectonicblocksarefurtherusedinthispapertoanalyzetherelationshipbetweentheMs≥7.0eventsinChinesemainlandandthemodulationandtriggeringfromtheearthtides.TheresearchshowsthattheMs7.0eventsinChinesemainlandhavebeensignificantlytriggeredbythetidalstress,especiallywithintheactiveperiodwithgroupstrongearthquakes.Inthequiescenceperiodofstrongearthquakes,noMs7.0eventsweretriggered,whilewithintheactiveperiod,over82.4%ofstrongearthquakestookplacewithinaspecialmoonphase,whichis36.4%higherthantheaverage.Therefore,themodulationandtriggeringoftidalstresscanbeusedtodistinguishtheactiveperiodsandtoforecastthetimeofthestrongearthquakeswithintheactiveperiod.Therelationshipbetweenthetidaltriggeringandthetectonicdynamicconditionisinvestigatedandthemechanismofthemodulationissimulatedwiththegroupmodelofearthquakesgeneratedintectonicblocks.
简介:AstudyoftheKunlunshanearthquakeofMS=8.1basedonobservedcoseismicstrainstepsfromtheboreholestrainmonitoringnetworkoverChinahasbeencarriedoutwithsomeinterestingresults.Firstly,manyrecordingsdisagreewiththeoreticcalculationusingstaticdislocationmodel.Secondly,abnormallylargestrainstepsareobservedatquiteafewstationsinthetectonicallyactiveeast-northernChina,whileintherelativelyinactiveeast-southernChinanoobviousstepsarerecorded.Itisinferredthatseismicstresstriggeringmaysignificantlyaffectremoteseismicstrainfield.Inotherwords,whetherremotefaultingbeseismicallytriggeredornotmaydeterminethepatternoflocalseismicstrainchanges.FurthercomparisonstudyresultsofMarch11,1999ZhangbeiearthquakeandNovember1,1999Datongearthquakeshowthatthespecificpatternofseismiczoneshasobviousinfluenceonseismicstrainchangesintheregion.Thissupportstheideathatobservedabnormalstrainstepsmightbeproducedbycoseismiclystress-triggeredlocalfaulting.
简介:CatalystcontainingshapeselectivezeoliteisusedtoinvestigatethecatalyticcrackingcharacteristicsofpalmoilandthreetypesofhydrocarbonVGOsonafixedfluidizedbed(FFB)unit.Theadvantageofproducinglightolefinsandlightaromaticsbycatalyticcrackingofplantoilisdiscussed.Resultsindicatethatthehydrocarbylgroupoftheplantoilmoleculeisquitereadilycrackable;theC6-C8aromaticsyieldiswellaboveandthelightolefinsyieldisaboutthesamewiththehydrocarbonfeeds,whiletheyieldsoflowvalueproductsarelower;thehydrocarbylgroupoftheplantoilmoleculehasstrongtendencyofaromatization,andcanenterthezeoliteporestoselectivelyformC6-C8aromatics;duringcatalyticcrackingofplantoilandfattyacids,aportionoftheoxygenisremovedintheformofwaterthroughhydrogentransferreaction,whileolefinsarepreventedfrombeingsaturated,whichcanensureproperyieldsofbothlow-carbonolefinsandlightaromatics.
简介:ThispapercalculatesthestaticCoulombstresschangesgeneratedbyfourearthquakesintheYutianareaduring2008~2014separately,thendiscussesthetriggeringinfluence,theiraccumulatedCoulombstresschangesandtheirinfluenceonnearbyfaults.TheresultsindicatethattheMS5.5earthquakein2011andtheM_S7.3earthquakein2014arebothintheregionswheretheCoulombstresschangeispositive,thestresschangesare0.004MPaand0.021MPa,respectively,meaningtheyaretriggeredbypriorearthquakes.TheMS6.2earthquakein2012occurredintheplacewhereCoulombstresschangewasnegative,soitispostponedbythepriorearthquakes.TheimageofCoulombstresschangesoftheMS7.3earthquakein2014isinaccordwithaftershocks(ML≥3.0)distribution,butsomeregionsonthefaultwheretheCoulombstresschangeispositivehavefewaftershocks,andstrongaftershocksmayoccuratthesedistrictsinfuture.Inaddition,thispapercalculatestheCoulombstresschangeonnearbyfaults,andfindsthattheCoulombstresschangesofdifferentelementsintheGGCfaultareverydifferent,andmustreceivestrongtriggered-influence,thoughtheresultmaybeinfluencedbytheinputfinitefaultmodel,sothereisstillalargeearthquake-risk.TheGGN,PLC,PLWandLBWfaultswerealsotriggeredbythefourearthquakesoccurringbetween2008~2014.TheirmaximumCoulombstresschangesallexceed0.002MPa,sotheyalsohaveastrongearthquakehazard.
简介:AstatisticalanalysisonearthquakeactivityintheKashi-WuqiaintersectionareatriggeredbyearthtideisdonebySchusterstestandthePermutationtestondailyandmonthlyscales.Thenorth-south,east-westcomponentofthetidalforceandtidalbodystressarechosenasthetidalcurveinthedailyscale.Theresultsshowthatmostoftheearthquakesoccurrednearthemaximum0°ofthethreekindsoftidalcurves,thepredominanttidalphasesoftheearthquakeare-5.86°,6.60°and-15.52°,andthefrequencyoftheearthquakesincreaseswiththeincreaseofthetide;withthreekindsoftidalcurves(thenorth-south,east-westcomponentofthetidalforceandtidalbodystress),thepSofSchusterstestforalltheearthquakesis10.52%,2.40%and2.06%,andthepPofthePermutationtestis10.90%,2.40%and2.06%,andtheresultsofpSandpPbasedontheeast-westcomponentofthetidalforceandtidalbodystressarebelowthethresholdof0.05thattidaltriggeringofearthquakes.Inthemonthlyscale,boththepSandpPareverylow(closeto0),farbelowthethresholdof0.05oftidaltriggeringofearthquakes,andthepredominanttidalphaseforearthquaketriggeringis-18.95°,closetothemaximum0°(newmoonandfullmoon)oftheearthtideinmonthlyscale.Regardingthestatisticaltestresultoftidaltriggeringofearthquakes,apreliminaryexplanationisgivenastowhythetriggereffectintheeast-westdirectionisgreaterthanthatinnorth-southdirection.