Using digital seismic waveform recorded by the Inner Mongolia seismic network from January 2008 to December 2017, the focal mechanisms of 138 ML≥2.5 earthquakes in eastern Inner Mongolia are calculated by P-wave initial motion and amplitude ratio (FOCMEC) method. The analysis of focal mechanism solution shows that the main source types in the study area are strike-slip with a certain proportion of thrust, while normal faults types are relatively few. The advantageous directions of P-axis and T-axis are NEE-SWW and NNW-SSE directions, respectively. The study area is divided into 1°×1°. The stress tensor and stress field images of the study area are obtained by damped stress inversion (MSATSI) method. The inversion results of stress field show that the stress state in eastern Inner Mongolia is mainly strike-slip, but shear and compression exist in some areas. The maximum principal stress square mainly distributes in NEE-SWW direction and rotates clockwise from north to south."/>
Inversion of Tectonic Stress Field in Eastern Inner Mongolia by Focal Mechanism
Abstract Using digital seismic waveform recorded by the Inner Mongolia seismic network from January 2008 to December 2017, the focal mechanisms of 138 ML≥2.5 earthquakes in eastern Inner Mongolia are calculated by P-wave initial motion and amplitude ratio (FOCMEC) method. The analysis of focal mechanism solution shows that the main source types in the study area are strike-slip with a certain proportion of thrust, while normal faults types are relatively few. The advantageous directions of P-axis and T-axis are NEE-SWW and NNW-SSE directions, respectively. The study area is divided into 1°×1°. The stress tensor and stress field images of the study area are obtained by damped stress inversion (MSATSI) method. The inversion results of stress field show that the stress state in eastern Inner Mongolia is mainly strike-slip, but shear and compression exist in some areas. The maximum principal stress square mainly distributes in NEE-SWW direction and rotates clockwise from north to south.
ZHANG Fan,WANG Xiaoshan,NA Renhua et al. Inversion of Tectonic Stress Field in Eastern Inner Mongolia by Focal Mechanism[J]. jgg, 2020, 40(8): 771-777.
ZHANG Fan,WANG Xiaoshan,NA Renhua et al. Inversion of Tectonic Stress Field in Eastern Inner Mongolia by Focal Mechanism[J]. jgg, 2020, 40(8): 771-777.
