Abstract
To better quantify the relatively long period (< 0.3="" hz)="" shaking="" experienced="" during="" the="" 2015="" gorkha="" (nepal)="" earthquake="" sequence,="" we="" study="" the="" finite="" rupture="" processes="" and="" the="" associated="" 3d="" ground="" motion="" of="" the="" mw7.8="" mainshock="" and="" the="" mw7.2="" aftershock.="" the="" 3d="" synthetics="" are="" then="" used="" in="" the="" broadband="" ground="" shaking="" in="" kathmandu="" with="" a="" hybrid="" approach,="" summarized="" in="" a="" companion="" paper="" (chen="" and="" wei,="" 2017,="" submitted="" together).="" we="" determined="" the="" coseismic="" rupture="" process="" of="" the="" mainshock="" by="" joint="" inversion="" of="" insar/sar,="" gps="" (static="" and="" high-rate),="" strong="" motion="" and="" teleseismic="" waveforms.="" our="" inversion="" for="" the="" mainshock="" indicates="" unilateral="" rupture="" towards="" the="" ese,="" with="" an="" average="" rupture="" speed="" of="" 3.0="" km/s="" and="" a="" total="" duration="" of="" similar="" to="" 60="" s.="" additionally,="" we="" find="" that="" the="" beginning="" part="" of="" the="" rupture="" (5-18="" s)="" has="" about="" 40%="" longer="" rise="" time="" than="" the="" rest="" of="" the="" rupture,="" as="" well="" as="" slower="" rupture="" velocity.="" our="" model="" shows="" two="" strong="" asperities="" occurring="" 24="" s="" and="" 36="" s="" after="" the="" origin="" and="" located="" similar="" to="" 30="" km="" to="" the="" northwest="" and="" northeast="" of="" the="" kathmandu="" valley,="" respectively.="" in="" contrast,="" the="" mw7.2="" aftershock="" is="" more="" compact="" both="" in="" time="" and="" space,="" as="" revealed="" by="" joint="" inversion="" of="" teleseismic="" body="" waves="" and="" insar="" data.="" the="" different="" rupture="" features="" between="" the="" mainshock="" and="" the="" aftershock="" could="" be="" related="" to="" difference="" in="" fault="" zone="" structure.="" the="" mainshock="" and="" aftershock="" ground="" motions="" in="" the="" kathmandu="" valley,="" recorded="" by="" both="" strong="" motion="" and="" high-rate="" gps="" stations,="" exhibited="" strong="" amplification="" around="" 0.2="" hz.="" a="" simplified="" 3d="" basin="" model,="" calibrated="" by="" an="" mw5.2="" aftershock,="" can="" match="" the="" observed="" waveforms="" reasonably="" well="" at="" 0.3="" hz="" and="" lower="" frequency.="" the="" 3d="" simulations="" indicate="" that="" the="" basin="" structure="" trapped="" the="" wavefield="" and="" produced="" an="" extensive="" ground="" vibration.="" our="" study="" suggests="" that="" the="" combination="" of="" rupture="" characteristics="" and="" propagational="" complexity="" are="" required="" to="" understand="" the="" ground="" shaking="" produced="" by="" hazardous="" earthquakes="" such="" as="" the="" gorkha="">