【摘要】 基于新疆及西藏区域数字地震台网的宽频带资料,采用CAP方法反演了2014年2月12日于田7.3级地震的前震、主震及早期MS≥3.5余震序列的震源机制解。结果显示,此次7.3级强震为带有正断分量的走滑型地震,结合震源区的构造和余震分布,节面I走向241°/倾角90°/滑动角-22°,判定该节面代表了主震的发震断层面。主震主压力轴方位为194°,与该区历史中强震主压应力P轴方位近NS向较为接近。其5.4级前震和主震震源机制解具有较高的一致性。18次余震中有10次为走滑型地震,其中6次为正断型,2次为逆断型,且70%的地震的P轴方位近SN向。此次7.3级地震序列震源深度为5~28km,而大部分地震为15~20km,略大于本文得到的主震震源深度10km。更多还原

【Abstract】 Based on the broadband waveforms recorded by the Xinjiang and Tibetan Digital Seismic Networks,we inversed the focal mechanism solutions of the main shock,foreshock and MS≥3. 5 aftershocks of the MS7. 3 earthquake,by using the CAP method. The results showed that the focal mechanism of the main shock had Nodal plane I with strike 241° / dip 90° / rake- 22°,and Nodal plane II with strike 331° / dip 68° / rake- 180°,and the focal depth was about 10 km. Combined with the active geologic structures of the seismic area,Nodal plane I was identified to be the seismogenic fault plane of the main shock. The direction of P-axis for the main shock was 194°,closed to the NS direction of P-axis of history earthquakes this area. The MS5. 4 foreshock,main shock and 10 aftershocks were strike-slip earthquakes. 6 aftershocks were normal faulting and 2 aftershocks were thrust type earthquakes. 70% of earthquake in the sequence had near NS direction P-axis. The focal depth of this MS7. 3 earthquake sequence distributed 5 ~28km,most of the earthquakes occurred within the depth range of 15 ~ 20 km,slightly deeper than the focal depth 10 km we calculated.更多还原