【摘要】 利用IRIS全球台网记录到的远场波形对2012年新源、和静交界MS6.6地震的破裂过程进行了反演,同时,结合发震构造喀什河断裂东段的构造特征和MS6.6地震前天山中段区域应力场状态,对MS6.6地震的可能发生机理进行了讨论。结果表明:1)MS6.6地震破裂持续时间约35s,地震能量主要在前16s内释放。整个破裂过程由2次子事件组成,第1次破裂强度大于第2次。此次地震破裂过程相对简单,具有双侧破裂特征,最大滑移量为45cm。MS6.6地震初始破裂点位于高滑动量区域的边缘,深部主体破裂区以逆冲兼右旋走滑错动为主,浅部以右旋走滑错动为主;2)MS6.6地震的3级以上余震主要分布在主震破裂大滑动量区域的外围或滑动量变化梯度较大的区域,主震发生后短期内余震的震源机制特征与主震破裂面在断层面上产生的滑动矢量分布较为一致;3)新源、和静交界MS6.6地震前,新疆地区逆冲类型的中强地震明显增多,尤其是天山中段,且这些地震的震源机制与区域应力场的状态较为一致。显示了天山中段受构造应力场控制作用增强,进而有利于具有右旋扭错性质的喀什河断裂东段发生右旋走滑运动,这可能是6.6级地震发生的直接原因。更多还原

【Abstract】 By using the digital teleseismic seismograms recorded by the global network( IRIS),we studied the rupture process of the MS6. 6 earthquake of Jun. 30,2012,in the border area between Xinyuan and Hejing Counties. In addition,based on the tectonic feature of the eastern segment of Kashi River Fault and regional stress state in the central segment of Tienshan region before the MS6. 6 earthquake,we discussed the possible seismogenic mechanism of the MS6. 6 earthquake. The result indicates that the lasting time of the MS6. 6 earthquake’s rupture process is about 35 s and the main energy release appears in the early 16 s. The total rupture process consists of two sub-events,strength of the first rupture is higher than the second one. The rupture process is relatively simple and has bilateral rupture characteristics; the maximum slip amount is 45. 0cm. The initial rupture point of the MS6. 6earthquake locates on the verge of high slip amount area,the dislocation mode of main rupture area in the depth is reverse and right-lateral strike-slip type,and the one in the shallow is mainly right-lateral strike-slip type; MS≥3. 0 aftershocks are mainly distributed on the verge of high slip amount area or high gradient area of slip amount change; the feature of focal mechanisms of those aftershocks occurring within the short time after the mainshock is consistent with the slip vector distribution on the fault surface; The mid-strong earthquakes with reverse fault type taking place before the MS6. 6earthquake had increased obviously in Xinjiang area,especially in the central segment of Tienshan area,and the azimuth and plunge of P axis of these earthquakes are consistent with the regional stress field. This suggests to a certain extent that the central segment of Tienshan area is more under the control of the tectonic stress field,which may promote the right-lateral strike-slip motion on the rightlateral wrench faulting eastern segment of the Kashi River Fault. And this may be the generating mechanism of the MS6. 6 earthquake.更多还原