Coseismic surface-ruptures and crustal deformations of the 2008 Wenchuan earthquake Mw7.9, China



[1] The irregularly distributed surface fault-ruptures of the Wenchuan earthquake spanned over 200 km along the Longmen Shan(LMS) fault zone. Through field investigations, we found over 10 coseismic surface-ruptures, with maximum vertical displacements of approximately 6 m on the Yingxiu-Beichuan fault and 2 m on the Guanxian-Anxian fault; however, the entire fault rupture movement was still not clearly understood since high topographic areas were inaccessible. Thus, we used interferometric synthetic aperture radar (InSAR) satellite observations to capture whole coseismic surface-ruptures and crustal deformations across the LMS faults. We created a novel bi-fault-slip model to invert fault-slips using InSAR information which yielded that thrust fault-slips were dominant at YingXiu, Houshenggou and Bajiaomiao in the near-epicenter segment, while the dextral fault-slips were dominant at Pingtong and Nanba along the northeast segment. The combination of field investigations and simulations suggested that the two coseismic fault zones ruptured with an irregular surface distribution accompanied by crustal deformations.