The dynamics of earthquake precursors controlled by effective friction
The dynamics of earthquake precursors controlled by effective friction
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有效摩擦力控制的地震前兆动力学
DOI：
10.1093/gji/ggx438
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发表时间：
2018
影响因子：
2.8
通讯作者：
P. Dublanchet
中科院分区：
文献类型：
--
作者：
P. Dublanchet
许多大地震之前都有缓慢滑动和前震序列。这些异常现象激活了主震断层的震源区。然而，慢滑动事件和震群并不系统地导致大地震，不能被认为是短期预测。了解是什么控制了构造断层上前兆的发生和动态，对改进地震危险性评估至关重要。这项研究表明，有限平面断层上的摩擦不均匀性如何以统一的艾德方式解释大地震前的不同断层行为。它表明，在非均匀条件下，四个不同的地区的地震成核发生。所有这些都以缓慢的滑动加速为特征，但只有一个涉及到越来越多的前震活动。不同制度之间的过渡，和断层滑动历史之前的主震是在四个制度控制的有效摩擦参数，并通过断裂力学标准，涉及的特征波长的非均匀性。这里开发的地震成核的有效摩擦理论可能有重大影响，在其他故障过程的非均质条件下，如动态破裂或幕式慢滑事件的理解。
SUMMARY Many large earthquakes are preceded by slow slip and foreshock sequences. These precursory phenomena activate the hypocentral region of the main-shock fault. However, slow slip events and earthquake swarms do not systematically lead to large earthquakes and cannot be considered for short-term prediction. Understanding what controls the occurrence and the dynamics of precursors on tectonic faults is of critical importance to improve seismic hazard assessment. This study shows how frictional heterogeneity on a finite planar fault can explain the different fault behaviours preceding a large earthquake in a unified manner. It is demonstrated that under heterogeneous conditions, four different regimes of earthquake nucleation occur. All of them are characterized by slow slip acceleration, but only one involves a growing foreshock activity. The transitions between the different regimes, and the fault slip history preceding the main-shock are in the four regimes controlled by effective friction parameters, and by a fracture mechanics criterion involving the characteristic wavelength of heterogeneity. The effective friction theory developed here for earthquake nucleation may have major implications in the understanding of other fault processes under heterogeneous conditions, such as dynamic rupture or episodic slow slip events.