Modeling of slow slip events along the deep subduction zone in the Kii Peninsula and Tokai regions, southwest Japan
Modeling of slow slip events along the deep subduction zone in the Kii Peninsula and Tokai regions, southwest Japan
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日本西南部纪伊半岛和东海地区深俯冲带慢滑移事件的模拟
DOI：
10.1029/2011jb009083
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发表时间：
2012
影响因子：
--
通讯作者：
H. Hirose
中科院分区：
文献类型：
--
作者：
B. Shibazaki;K. Obara;T. Matsuzawa;H. Hirose
[1]在日本西南部的俯冲带，每隔几个月就会发生一次短期慢滑事件(SSE)，并伴有低频地震(LFT)。最近，对LFT进行了高分辨率定位，并对它们的活动进行了详细检查。通过设置SSE的产生区，使这些区域包含LFT震中，我们在Kii半岛和东海地区下方的3D板块界面上，使用具有小截止速度的速率和状态相关的摩擦定律来模拟SSE的演化效应。我们的数值结果表明，Kii半岛南部和中部、Kii半岛北部和东海地区SSE的重现间隔分别为2.5-3.0个月、4.8-5.6个月和3.5-4.5个月，这与观测到的SSE活动一致。我们的模拟还产生了一个多段事件，它以10公里/天的速度从Kii段传播到东海段，这与观测结果是一致的。结果表明，LFTs的产生带与SSE区重合，这两个事件是同一滑移过程在俯冲带上的不同表现。我们还通过考虑临界位移较小的局部圆形斑块，以及临界位移较大的SSE区域，对伴随着短期SSE的较快事件进行了3D模拟。在观测到的LFT位置设置局部圆形贴片。模拟再现了在单个SSE事件期间以100-200公里/天的速度传播的快速事件。
[1] In the subduction zone of southwest Japan, short-term slow slip events (SSEs) occur with low frequency tremors (LFTs) at intervals of several months. Recently LFTs have been located with high resolution and their activities have been examined in detail. By setting the generation zones of SSEs such that these zones contain the LFT hypocenters, we simulate SSEs on a 3D plate interface beneath the Kii Peninsula and Tokai regions by using a rate- and state-dependent friction law with a small cut-off velocity for the evolution effect. Our numerical results show that recurrence intervals of SSEs in the southern and central Kii Peninsula, in the northern Kii Peninsula, and in the Tokai region are 2.5–3.0, 4.8–5.6, and 3.5–4.5 months, respectively, which are consistent with observed SSE activity. Our simulation also produces a multisegment event that propagates from the Kii to Tokai segments at a speed of 10 km/day, which is consistent with observations. The results suggest that generation zones of LFTs coincide with SSE regions and that these two events are different manifestations of the same slip process along the subduction zone. We also perform 3D modeling of faster events accompanied by short-term SSEs by considering local circular patches with a smaller critical displacement, surrounded by SSE zones with a larger critical displacement. Local circular patches are set at the observed LFT locations. The simulation reproduces fast events that propagate at a speed of 100–200 km/day during a single SSE event.