论文部分内容阅读
本研究将利用余震分布和区域应力场确定大震断层面参数的方法应用于2010年玉树MS7.1级地震发震断层面参数的确定,获得了本次地震断层面参数为:走向294.6°,倾角78.0°,滑动角7.5°,属于左旋走滑型地震和甘孜—玉树断裂带的性质相一致.主震前后应力场反演结果表明该区域的应力场为:中间主应力轴近直立,最大和最小主应力轴近水平,且发现玉树地震前后震源区应力场存在偏转现象,最大主压应力轴由震前的NEE向逆时针旋转至震后的NNE向,震后最大主压应力轴与断层走向近垂直,表明主震对震源区应力释放较为充分.
In this study, the method of using aftershock distribution and regional stress field to determine the fault plane parameters of large earthquakes was applied to the determination of the seismogenic fault plane parameters of the Yushu MS7.1 earthquake in 2010. The parameters of this fault section are 294.6 °, Inclination angle of 78.0 ° and sliding angle of 7.5 ° are consistent with the characteristics of left-lateral strike-slip earthquakes and the Garze-Yushu fault zone.The inversion of stress field before and after the main shock shows that the stress field in this region is: the middle principal stress axis is nearly upright and the maximum And the minimum principal stress axis is near horizontal. The stress field in the source region before and after the Yushu earthquake is found to be deflected. The maximum principal compressive stress axis rotates counterclockwise from the pre-earthquake NNE to the post-earthquake NNE direction. The maximum principal compressive stress axis The faults are nearly perpendicular to each other, indicating that stress release from the mainshock in the source area is sufficient.