On June 1, 2022, an M(S)6.1 earthquake hit the Lushan County, Sichuan Province, southwestern China. Based on the data from Sichuan Regional Seismic Network, the S6.1 Lushan earthquake sequence with M-L = 1.0 (June 1-7, 2022) was relocated by HypoDD method. Focal mechanisms and centroid depths of the M-S >= 3.0 earthquakes were inverted by the gCAP (generalized Cut And Paste) method. Meanwhile, the stability of focal mechanism of the mainshock was evaluated by Bootstrap method and the minimum rotation angles of the central solution of multiple focal mechanisms from various sources were calculated. Relative shear stress and normal stress on nodal planes from focal mechanisms of the 2022 M(S)6.1 Lushan earthquake and the 2013 M(S)7.0 Lushan earthquake were calculated under the contemporary regional stress field, and the seismogenic fault plane was fitted by relocated distribution of Lushan earthquake sequence. The seismogenic structure of the 2022 M(S)6.1 Lushan earthquake sequence was analyzed. The main results are as follows: (1) The relocation distribution show that the aftershocks are mainly along Shuangshi-Dachuan fault and the predominant direction is to NE-SW. The events distribute in the 10 similar to 18 km depth range and the average depth of relocated earthquakes is 14.5 km. The shallow earthquakes distribute in the northwest and the deep in the southeast, and Lushan M(S)6.1 mainshock and M(S)4.5 aftershock are located in the southeast of the aftershocks region. Most of aftershocks are located in the northwest of the mainshock. The earthquake sequence shows the characteristics of unilateral rupture, and the fault plane dips to SE. (2) Both Bootstrap method and the minimum spatial rotation angle of the central solution of multiple focal mechanisms show that the error of the mainshock focal mechanism obtained by gCAP method is small, indicating that the results are reliable and stable. The mainshock focal mechanism solution is strike: 228 degrees, dip: 46 degrees and rake: 106 degrees for nodal plane I, and strike: 26 degrees, dip: 46 degrees and rake: 74 degrees for nodal plane II, and the centroid depth is 12 km while the moment magnitude is M(W)5.8. The focal mechanism inversion results show that the MS >= 3.0 earthquakes are mainly thrust earthquakes and the centroid depths are in 11 similar to 13 km range. P-axis azimuths are primarily in NW-SE direction which is consistent with the regional stress field. (3) Simulation on relationship between focal mechanisms and stress regimes reveals that the shape of fault plane of the 2022 M(S)6.1 Lushan earthquake and the 2013 M(S)7.0 Lushan earthquake inhibits the full release of stress. According to available geologic structure and results above, it is concluded that nodal plane ? of focal mechanism of 2022 MS6.1 Lushan earthquake is the seismogenic fault of earthquake. The seismogenic structure of the 2022 MS6.1 Lushan earthquake sequence is probably a NE-striking blind thrust fault which is dipping towards SE. It also may be related to the secondary backthrust fault on the NE-striking and NW-dipping seismogenic structure of the 2013 M(S)7.0 Lushan earthquake.
