Deep slow-slip events promote seismicity in northeastern Japan megathrust
Deep slow-slip events promote seismicity in northeastern Japan megathrust
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DOI：
10.1016/j.epsl.2020.116261
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发表时间：
2020-06
影响因子：
5.3
通讯作者：
M. Khoshmanesh;M. Shirzaei;N. Uchida
中科院分区：
文献类型：
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作者：
M. Khoshmanesh;M. Shirzaei;N. Uchida
俯冲带中海洋板块与地壳板块之间的滑动运动是通过地震和准静态或短暂的无震滑动来调节的。在日本东北部的巨型逆冲断层，地震瞬变，被称为慢滑事件，建议之前，并触发其附近的大地震。然而，这些情节慢滑事件的大地测量证据，以及他们的联系，对相邻的锁定段的巨型逆冲断层的地震活动，是失踪。在这里，我们结合联合收割机的陆上大地测量数据集与地震观测期间的1996-2003年，并证明，幕式慢滑事件是普遍的下倾部分（30-70公里深度）的巨型逆冲断层和相关的应力变化调制的地震活动率对邻近孕震区。因此，小到中等规模的地震被周期性地触发，它们通过多米诺骨牌效应的相互作用偶尔可能导致大地震。这一观测结果对估计该区域的地震危险性产生了深远影响，它引入了一种新的触发机制，这种机制在以前未被承认的程度上作用于整个巨型逆冲断层。
The sliding movement between oceanic and crustal plates in subduction zones is accommodated through both earthquakes and quasi-static or transient aseismic slip. On northeastern Japan megathrust, aseismic transients, known as slow-slip events, are suggested to precede and trigger major earthquakes in their immediate surroundings. However, the geodetic evidence for these episodic slow-slip events, as well as their link to the seismicity on neighboring locked segments of the megathrust, is missing. Here, we combine the on-shore geodetic data set with seismic observations during the interseismic period of 1996–2003 and demonstrate that episodic slow-slip events are prevalent across the down-dip portion (∼30–70 km depth) of the megathrust and the associated stress changes modulate the seismicity rate on the neighboring seismogenic zone. Consequently, small- to moderate-size earthquakes are periodically triggered, whose interaction through a domino effect might occasionally lead to major earthquakes. This observation has a profound impact on the estimation of seismic hazard in the region, introducing a new triggering mechanism that acts across the megathrust to the extent that has not been acknowledged before.