Co-seismic deformation due to the 20 March 2008 Yutian earthquake (M7.2) in Tibet and its Fault Model

On 20 March 2008, an earthquake (M7.2) struck northern Tibet, west Kunlun, China. Because of the high altitude (> 4500 meters), no casualties were reported associated with this earthquake. However, the associated crustal deformation signals, if detected and examined in detail, will provide us with important constraints on how the continental crust in Tibetan plateau has been deforming, which has been contentious over the past decades. It has been known from seismological studies that a combination of normal and strike-slip faulting earthquakes prevail over the central to northern areas of Tibet. The nodal planes in those fault solutions, however, remain uncertain, because those solutions have been usually base on far-field seismological data, and near-field observations have been lacking. Here we report our detection of the associated crustal deformation signals using SAR data, and its fault source model. Despite the high altitude and the seasons of that data we used, the interferometric coherence was rather good, providing us with excellent data covering almost the entire deformed areas. The earthquake source mechanism was, as a seismological study already suggested, of normal faulting, but the slipped region was probably shallower than the estimate. We will present our fault source model derived from SAR observation data.