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。

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 10km． 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 ～ 20km，slightly deeper than the focal depth 10km we calculated．

新疆地震局基金(201401)和2014 年度震情跟踪合同制定向工作任务(2014020106)联合资助