西南天山—帕米尔2008年10月5日M_S6.7级地震震源机制研究

A study of focal mechanisms of the M_S6.7 earthquake of 5 October 2008 in southwestern Tianshan-Pamier

利用Incorporated Research Institutions for Seismology(IRIS)提供的远场宽频带P波及SH波记录,基于点源模型及有限断层模型方法,反演研究了2008年10月5日发生在中国天山与塔吉克斯坦交界区域的一次MS6.7级地震震源机制.结果表明,本次地震为南倾高角度稍具小幅度走滑分量的逆冲破裂事件,断层走向为57.2°,倾角为42.7°,震源深度为7.4km.根据研究结果,我们认为这是一次逆断层加小幅度走滑分量的地震事件,推断该地震可能与帕米尔向北北西方向挤压西南天山,在帕米尔—西南天山边界引发的逆冲断层活动有关.

The rupture process of the Ms6. 7 earthquake occurring near the border between Xinjiang and Tajikistan on 5 October 2008 was investigated by pointsource and finite fault models using far field broadband P and SH waves provided by the IRIS. The results suggest that this shock resulted from rupturing on a southdipped thrust fault with lateral strike slip. The fault plane has a strike of 57.2%, a dip of 42.7% and focal depth of 7.4 kin. Based on our inversion, we proposed that this earthquake was generated by thrust faulting due to NNW directed pushing of the Pamir toward the southwestern Tianshan Mountains.