Continuous estimates on the earthquake early warning magnitude by use of the near-field acceleration records

Inthisarticle,theseismicrecordsofJapan’sKik-netareselectedtomeasuretheacceleration,displacement,andeffectivepeakaccelerationofeachseismicrecordwithinacertaintimeafterPwave,thenacontinuousestimationisgivenonearthquakeearlywarningmagnitudethroughstatisticalanalysismethod,andWenchuanearthquakerecordisutilizedtocheckthemethod.Theresultsshowthatthereliabilityofearthquakeearlywarningmagnitudecontinuouslyincreaseswiththeincreaseoftheseismicinformation,thebiggestresidualhappensiftheaccelerationisadoptedtofitearthquakemagnitude,whichmaybecausedbyrichhigh-frequencycomponentsandlargedispersionofpeakvalueinaccelerationrecord,theinfluencecausedbythehigh-frequencycomponentscanbeeffectivelyreducediftheeffectivepeakaccelerationandpeakdisplacementisadopted,itisestimatedthatthedispersionofearthquakemagnitudeobviouslyreduces,butitiseasyforpeakdisplacementtobeaffectedbylong-perioddrifting.Invariouscomponents,theresidualenlargementphenomenonatverticaldirectionisalmostunobvious,thusitisrecommendedinthisarticlethattheeffectivepeakaccelerationatverticaldirectionispreferredtoestimateearthquakeearlywarningmagnitude.ThroughadoptingWenchuanstrongearthquakerecordtocheckthemethodmentionedinthisarticle,itisfoundthatthismethodcanbeusedtoquickly,stably,andaccuratelyestimatetheearlywarningmagnitudeofthisearthquake,whichshowsthatthismethodiscompletelyapplicableforearthquakeearlywarning.