Abstract: Based on the digital waveforms of Xinjiang Seismic Network, The Shufu M_S5.1 earthquake sequence (M_L≥1.0) was relocated precisely by HypoDD. The best double-couple focal mechanisms of the main shock was determined by the CAP method. We analyzed the seismogenic structure of earthquake sequences.The results show that the main shock was relocated at 39.59°N, 75.57°E, the depth of the initial rupture and centriod is about 18.2 km and 18 km. The distribution of aftershocks presents an asymmetric conjugate shape in NEE and NE directions. The NEE is the main rupture distribution of the aftershocks with length of about 13 km which is closed to the Kashi fault. Another advantage is that the NE is about 9 km which may be related to the Kashi faults step.The characteristics of the depth profiles show that the focal depth of the earthquake were mainly located in the depth of 8~20 km. The depth profile of the NEE shows that the Shufu 5.1 earthquake ruptured to the depth and tended to be deeper. The depth profile perpendicular to the Kashi fault shows that the fault plane was dipping north. It showed that the focal mechanism of the main shock was thrust. The dip of nodal plane Ⅱ is consist with the dip of the depth profile, which is inferred from the seismogenic nodal. According to the precise positioning results derived, the focal mechanism and geological structure in the source region, a comprehensive analysis of the M_S5.1 earthquake seismogenic structure may be Kashi fault, and the aftershocks extend to shallow.

Key words: Shufu M_S5.1 earthquake, HypoDD location, focal mechanism, seismogenic structure, Kashi fault