2020-07-12河北唐山MS5.1地震震源参数及发震构造分析

基于河北区域数字地震台网资料，采用CAP波形反演方法计算2020-07-12唐山M_S5.1地震的震源机制解，同时采用sPL深度震相方法对震源深度进行精确测定。结果显示，唐山M_S5.1地震震源机制解节面Ⅰ走向143°、倾角83°、滑动角-14°，节面Ⅱ走向235°、倾角76°、滑动角-173°；sPL深度震相方法测定的主震震源深度为14 km，与CAP波形反演方法的计算结果一致。结合地震序列分布特征、等震线形态、区域地质构造及深地震反射剖面等资料分析认为，节面Ⅱ为发震断层面，并推测此次地震的发震断层为唐山-古冶断裂。

Source Parameters and Seismogenic Structure Analysis of the July 12,2020 Tangshan MS5.1 Earthquake

Based on seismic data provided by Hebei regional seismic network, we use the CAP waveform inversion method to obtain the focal mechanism of the July 12, 2020 Tangshan M_S5.1 earthquake. In order to get a more accurate focal depth, we employ the depth phase sPL fitting method to measure the focal depth. The results show the parameters of the focal mechanism solution of the mainshock are strike 143°, dip 83°, rake -14° for the nodal planeⅠ, strike 235°, dip 76°, rake -173° for the nodal plane Ⅱ, and centroid depth is 14 km. The result of the focal depth is 14 km by sPL phase method, which is the same as that measured by the methods of CAP. Combined with distribution of earthquake sequence, the seismic intensity map, tectonic setting and deep seismic reflection profiles, we conclude that the nodal plane Ⅱ is the seismogenic fault plane of this earthquake and the Tangshan-Guye fault is the control fault.