Relocation of the 2008 Panzhihua M_S6.1 Earthquake Sequence

The Panzhihua MS6. 1 earthquake sequence on August 30,2008 was relocated using the Hypo2000 + Hypo DD algorithm with the seismic phase data from the Sichuan and Yunnan regional digital seismic networks,and the results show that the epicenters are distributed in the near NS direction,the length of aftershock concentration zone is about 30 km,and the main shock is about 14 km in depth. The depth of the sequence is distributed in the range of 0- 4km and 5- 20 km,and the layer of 4- 5km depth is an apparent earthquake absence layer. The cross-section along the fractures long axis shows there is an irregular seismic gap in the middle segment of the aftershock region,which is the rupture region of the M6 3/4 earthquake in 1955,and this earthquake occurred in the south of the gap. We believe that the Panzhihua MS6. 1 earthquake sequence on August 30,2008 was a result of rupture of the residual asperity caused by the stress adjustment of the Wenchuan MS8. 0 earthquake. The other two profiles perpendicular to the long axis show that the focal depth in the north segment is larger and the fault plane dips NW,which is consistent with the dip of the Hongge fault.

The Panzhihua Ms6. 1 earthquake sequence on August 30, 2008 was relocated using the Hypo2000 ＋ HypoDD algorithm with the seismic phase data from the Sichuan and Yunnan regional digital seismic networks, and the results show that the epicenters are distributed in the near NS direction, the length of aftershock concentration zone is about 30kin, and the main shock is about 14km in depth. The depth of the sequence is distributed in the range of 0 -4km and 5 -20km, and the layer of 4 -5kin depth is an apparent earthquake absence layer. The cross-section along the fracture＇s long axis shows there is an irregular seismic gap in the middle segment of the aftershock region, which is the rupture region of 3 the M6 3/4earthquake in 1955, and this earthquake occurred in the south of the gap. We believe that the Panzhihua Ms6. 1 earthquake sequence on August 30, 2008 was a result of rupture of the residual asperity caused by the stress adjustment of the Wenchuan Ms8. 0 earthquake. The other two profiles perpendicular to the long axis show that the focal depth in the north segment is larger and the fault plane dips NW, which is consistent with the dip of the Hongge fault.