【摘要】 利用大量远场观测地震图反演了新疆伽师地区三次不同机制类型M_s6级地震的破裂过程.结果表明。1998年8月2日M_s6.1级地震破裂尺度小,破裂过程简单,最大滑动量为12 cm,主破裂过程持续时间为8 s.1998年8月27日M_s6.5地震破裂过程的空间分布反映出双侧破裂特征。主破裂过程在前13 s基本完成,最大滑动量为63 cm,破裂面上起始破裂点两侧的滑动矢量方向不同.2003年2月24日M_s6.8地震的破裂过程最为复杂,震源时间函数由两次上升时间组成,破裂一共持续了32 s,最大滑动量为32 cm.研究表明,余震主要发生在主震破裂图像中大滑动量区域的外围或滑动量变化梯度较大的区域,主震后短期内发生的余震震源机制解也与破裂面上断层的错动方向一致,表明余震的位置和机制与主震破裂所引起的应力重新分布有关.更多还原

【Abstract】 By using the far field body waves,the temporal and spatial rupture process of 3 M_s 6.1 events with different focal mechanisms occurred in Jiashi,Xinjiang,from 1998 to 2003 were studied.The rupture pattern of Aug.2,1998,reveals that the rupture zone is small,the rupture process is simple and lasted about 8s,the maximum slip is 12cm.The rupture process of Aug. 27,1998,demonstrates a bilateral rupture characteristic,the process finished within 13s with the maximum slip of 63cm.The rupture process of M_s6.8 on Feb.24 2003 is the most complicated among them.Its source time function is composed of 2 rise periods,and totally lasted 32s,with the most slip 32cm.Our study reveals that aftershocks following the corresponding main shock occurred along the edge of area formed by large main shock slip on the fault plane,or on the area of slip rapidly decreased.Furthermore,aftershocks following the main shock within the first two weeks exhibit focal mechanisms coincident with the direction of the main shock slip,suggesting that the location and mechanism of aftershocks following the main shock are related with the stress redistribution after the main shock occurred.更多还原