Abstract We discuss the seismogenic structure of the Yingcheng MS4.9 earthquake on 2019-12-26 from aspects of seismology and geology. The sequence is relocated by HYPO2000 method. The results show that aftershocks are mainly distributed between Zaoshi and Changjiangbu faults, and are distributed in NW direction, which is basically consistent with the long axis direction of the intensity Ⅵ isoseismal in the field survey. The focal mechanism solution inverted by kiwi method shows that the main rupture is characterized by strike slip and thrust. The strike of plane Ⅰ is NE, which is consistent with Qianbei fault in the west of epicenter, but it is far away, and it is not consistent with the occurrence and stress mode of the fault. The strike of plane Ⅱ is NW, which is similar to Zaoshi fault and Changjiangbu fault. Through the analysis of dynamic mode of these faults, it is considered that under the control of NWW principal compressive stress in Jianghan basin, both Zaoshi fault and Changjiangbu fault are characterized by left-lateral strike slip. The strike of the main seismogenic plane is in the middle of two faults by an anticlockwise turn-slip due to the different strike. At the same time, the inclination of slip plane is also different with the actual fault plane, and aftershocks are partial to the east of the main shock. The analysis shows that the combined tectonic activity of Zaoshi fault and Changjiangbu fault triggered the Yingcheng MS4.9 earthquake sequence.
WU Haibo,CHEN Junhua,WANG Jie. Discussion of the Sequence and Seismogenic Structure of Yingcheng MS4.9 Earthquake on 2019-12-26[J]. jgg, 2021, 41(4): 419-424.
WU Haibo,CHEN Junhua,WANG Jie. Discussion of the Sequence and Seismogenic Structure of Yingcheng MS4.9 Earthquake on 2019-12-26[J]. jgg, 2021, 41(4): 419-424.
