1996年3月19日新疆阿图什6.9级地震:单侧破裂过程

THE 1996 ARTUX,XINJIANG,EARTHQUAKE: A UNILATERAL RUPTURE EVENT

结合已有的地质、余震分布及地震宏观考察资料 ,使用全球数字地震台网(GDSN)宽频带P波数据 ,利用波形拟合和有限断层的全局混合反演方法研究了 1 996年 3月1 9日新疆阿图什地震的震源破裂时空过程 .结果表明 ,这次地震是发生在柯坪断裂带的哈帕雷克断层上的一次具有逆倾和较小走滑分量的由西向东单侧破裂事件 .断层面的走向为2 52°,倾角 3 0°,震源深度为 1 3km ,震源持续时间为 1 5s.破裂面上的滑动分布主要由两部分构成 :初始破裂 0 .3m对应较小上升时间 0 .8s;最大滑动尺度 1 .0m则位于沿破裂方向离初始点约 2 5km处 ,相应的上升时间为 3 .5s.由于微观震中是指震源开始破裂的地方 ,而宏观震中则代表地面破坏最严重的区域 ,我们的反演结果解释了其他研究者得出的微观震中与宏观震中相距约 3

Using the broadband P wave records of the Global Digital Seismograph Network(GDSN) and the adaptive hybrid global search algorith,we investigate the rupture process of the 19 March,1996 Artux,Xinjiang,earthquake( M S=6.9). Slip vectors,risetime and rupture time for a finite fault are obtained and their errors is estimated by introducing a random weight method. Aftershock data,field geology and seismic investigations are applied to constrain the fault plane. This event occurred in the west part of the Kalpin fault zone and is a unilateral rupture thrust event with a small strike slip component. The fault plane has a stricke of 252° and a dip of 30°. The rupture duration is 15s and the focal depth is 13km. We conclude that the inferred slip distribution contains two major slip sources. A sub event with a slip amplitude of 0.3m and a risetime of 0.8s is located at the hypocenter. The maximum slip amplitude of 1.0m is associated with a 3.5s risetime subevent located to the east of the first major slip source. The distance between the two major slip sources is about 25km,and corresponds with the 30km difference between the instrumental and macroseismic epicenters. [