Fault geometry based on coseism ic ground displacemen ts from satellite images for the 2008 Wenchuan earthquake,Sichuan,China

Yu-Ting Kuo(郭昱廷),Yue-Gau Chen,Mong-Han Huang,John Suppe,Jean-Philippe Avouac,Sébastien Leprince,Francois Ayouband Yu-Ju Kuo

1)Department of Geosciences,Taiwan University,Taipei 10617 2)EPS,UC Berkeley,California 3)Division of Geological and Planetary Sciences,Caltech,California 4)Mathematics Department,Indiana University of Pennsylvania

On 12thMay 2008,a MW7.9 earthquake occurred on the Longmenshan fault in the mountains to the west of Sichuan Province,which shook many Asian cities and killed at least 69000 people.The surface ruptures strike NE and extend up to 270 km along the boundary between the eastern Tibetan Plateau and the Sichuan basin.It was difficult to comp lete the detailed mapping of surface ruptures and to measure fault slip in the field because w ell-defined features to co rrelate across the fault w ere rare in mountainous area.Near surface defo rmation is in fact composed of contributions from internal faulting and folding.U-sing the COSI-Corr software,we obtain coseismic ground displacements deduced from subpixel correlation of SPOT5 and ENV ISA T and also from D-InSAR on ENV ISA T.The results can provide continuous surface displacements.In the south,the results show significant shortening,generally＜10 meters,and two parallel ruptures,while in the north,they show strike slip dominant and only a single rupture.Based on our results,we simulate the fault geometry in different locations.To realize the long-term fault kinematics a comparison is further needed between coseismic deformation and long-term geomorphic deformation recorded in the landforms.