Surface Rupture and Coseismic Displacement of the Yushu M_S7.1 Earthquake,China

On April 14,2010,a devastating MS7.1 earthquake happened in Yushu County,Qinghai Province.Field geological investigation and remote sensing interpretation show that this earthquake generated an inverse L-type surface rupture of about 50 km,with a maximum displacement of no less than 1.3 m.The surface rupture can be divided into three parts:We found no obvious rupture traces for a long distance of 16km between the northern and middle part;the middle and the southern part showed a left-step arrangement,local features of each part presented a characteristic of right-step pinnate arrangement.The seismogenic Yushu fault is dominated by strike-slip motion,with a small amount of reverse component.Differential movement between the southern Qiangtang block and northern Bayankala block caused this earthquake.Earthquake recurrence period is 185~108 a.Along an approximately 20 km part of Ganzi-Yushu fault,between the southern surface rupture of Yushu MS7.1 earthquake and the 1896 earthquake,no surface rupture has been found,its seismic risk needs further research.