Imaging the rupture of 14 April, 2010 Yushu earthquake using back-projection of global subarray P-waves

We present the rupture details of Yushu earthquake from the back projection of teleseismic P waves. By applying ARF we get 29 out of 206 stations with distance range of 30 to 95 degree, which have a good array response function and high waveform cross-correlation coefficient, in the final back projecting process. We apply 4th root stack method and moving window with 2 sec length and 1 sec step to 100 sec long waveform starting 20 sec before P arrival. The back projection result shows that the total rupture time of the Yushu earthquake is 20 sec, and the rupture length is 60 km. The energy release of the Yushu earthquake is mainly concentrated at two time-space points. One is about 6 sec after the origin time and close to the epicenter. The second energy burst is 12 sec after the origin time and located southeast of the epicenter closing to the Jiegu county. This energy burst is the biggest energy burst in the whole source rupture process. The biggest energy burst is close to the heavily damaged area. The source rupture model from the back projection can aid the earthquake rapid response and rescue and can be a complement to ShakeMap.