A possible mechanism of M 9 earthquake generation cycles in the area of repeating M 7∼8 earthquakes surrounded by aseismic sliding
A possible mechanism of M 9 earthquake generation cycles in the area of repeating M 7∼8 earthquakes surrounded by aseismic sliding
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DOI：
10.5047/eps.2011.06.022
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发表时间：
2011-01-01
影响因子：
3
通讯作者：
Miyazaki, Shin'ichi
中科院分区：
文献类型：
--
作者：
Hori, Takane;Miyazaki, Shin'ichi
本文提出了一个在俯冲带中发生类似于9级大地震的机制，在俯冲带中只发现了类似于8级地震的7级地震，而震源区周围是地震滑动的。9级地震中，7级类似8个震源区及其周边地区均发生地震破裂，同震滑动量比7级类似8个地震的滑动量大一个数量级。为了再现这种行为，我们假设M9地震发生是俯冲带的基本破裂模式，M9震源区被建模为一个大的断裂能区，其成核大小与震源区的大小相当。类似于8个微凸体的M = 7被建模为较小的断裂能区域，其成核尺寸小于微凸体尺寸。基于这些假设，我们演示了一个简单的地震生成周期的数值模拟。结果与2011年东北太平洋沿岸地震的特征以及在此事件之前观察到的一些现象在定性上一致。
We propose a generation mechanism of a giant earthquake of magnitude (M) similar to 9 in subduction zones where only M = 7 similar to 8 earthquakes have been identified and the surroundings of the source areas are sliding aseismically. In an M 9 event, both the M = 7 similar to 8 source areas and the surrounding area rupture seismically and the coseismic slip amount is one order larger than that of M = 7 similar to 8 earthquakes. To reproduce such behavior, we assume that an M 9 earthquake occurrence is the fundamental rupture mode in the subduction zone, and the M 9 source area is modeled as a large fracture energy area whose nucleation size is comparable to the size of the source area. The M = 7 similar to 8 asperities are modeled as smaller fracture energy areas whose nucleation size is smaller than the asperity size. Based on these assumptions, we demonstrate a simple numerical simulation of earthquake generation cycles. The results are qualitatively consistent with the characteristics of the 2011 off the Pacific coast of Tohoku Earthquake and a number of phenomena observed prior to this event.