Relocation of three Yutian M_S≥5.0 earthquake sequences during 2011—2014 and their seismogenic structures

Based on the phase observation reports of Xinjiang regional digital seismic network， this paper relocated the three Yutian M_S≥5.0 earthquake sequences in the southwestern segment of the Altyn Tagh fault during 2011—2014 by using the double-difference location algorithm， and then analyzed the distribution of aftershocks and seismogenic structure of the sequences. The results show that the seismogenic structure of the Yutian M_S5.5 earthquake in 2011 is the Altyn Tagh fault， meanwhile small earthquakes were triggered in Pulu fault， and the earthquake sequence is distributed in nearly NS direction．The Yutian M_S6.2 earthquake sequence in 2012 is distributed mainly along the NNE direction， and its seismogenic structure is the Kuyake fault. The Yutian M_S7.3 earthquake sequence in 2014 is distributed in NE and NNE direction. Along the Altyn Tagh fault exist three aftershocks clusters， suggesting that the relocated small earthquakes may be a larger asperity to terminate the spread of the rupture， and its seismogenic structure is Ashikule fault and the Kuyake fault. In addition， characteristics of section of the Yutian sequences indicate that the secondary faults at the southwestern segment of the Altyn Tagh fault and the Pulu fault were ruptured by the three Yutian M_S≥5.0 earthquake sequences during 2011-2014．