A great earthquake doublet and seismic stress transfer cycle in the central Kuril islands
A great earthquake doublet and seismic stress transfer cycle in the central Kuril islands
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DOI：
10.1038/nature06521
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发表时间：
2008-01-31
期刊：
影响因子：
64.8
通讯作者：
Lay, Thorne
中科院分区：
文献类型：
--
作者：
Ammon, Charles J.;Kanamori, Hiroo;Lay, Thorne
与大的板间地震的粘滑周期相关的俯冲带板块边界断层上的摩擦阻力的时间变化被认为调制了俯冲洋板块内的应力状态和地震活动（1-3）。在这里，我们报告了两个大地震，发生在千岛群岛附近，揭示了这一过程，并证明了增强的地震危险性伴随触发断层。2006年11月15日，一个震级为8.3级的地震使太平洋板块沿沿着下降到千岛群岛中部弧下的浅倾板块边界破裂。逆冲断层破坏了一个地震空区，该空区以前具有不确定的孕震潜力（4、5），尽管早期发生的外隆挤压事件表明存在摩擦阻力（1、2）。在这次大规模的下冲事件发生后的几分钟内，板内伸展地震开始在千岛海沟向海的外部隆起区发生，2007年1月13日，一次矩震级为8.1的事件破坏了一个延伸穿过太平洋板块上部的正断层，产生了有记录以来最大的浅层伸展地震之一。这一强地震序列反映了俯冲岩石圈内的应力传递过程，这些大地震的明显破裂特征说明了板间和板内断裂的孕震性质和地震危险性的差异。
Temporal variations of the frictional resistance on subduction-zone plate boundary faults associated with the stick - slip cycle of large interplate earthquakes are thought to modulate the stress regime and earthquake activity within the subducting oceanic plate(1-3). Here we report on two great earthquakes that occurred near the Kuril islands, which shed light on this process and demonstrate the enhanced seismic hazard accompanying triggered faulting. On 15 November 2006, an event of moment magnitude 8.3 ruptured the shallow- dipping plate boundary along which the Pacific plate descends beneath the central Kuril arc. The thrust ruptured a seismic gap that previously had uncertain seismogenic potential(4,5), although the earlier occurrence of outer- rise compressional events had suggested the presence of frictional resistance(1,2). Within minutes of this large underthrusting event, intraplate extensional earthquakes commenced in the outer rise region seaward of the Kuril trench, and on 13 January 2007, an event of moment magnitude 8.1 ruptured a normal fault extending through the upper portion of the Pacific plate, producing one of the largest recorded shallow extensional earthquakes. This energetic earthquake sequence demonstrates the stress transfer process within the subducting lithosphere, and the distinct rupture characteristics of these great earthquakes illuminate differences in seismogenic properties and seismic hazard of such interplate and intraplate faults.