Numerical Modeling of Dynamically Triggered Shallow Slow Slip Events in New Zealand by the 2016 M w 7.8 Kaikoura Earthquake
Numerical Modeling of Dynamically Triggered Shallow Slow Slip Events in New Zealand by the 2016 M w 7.8 Kaikoura Earthquake
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2016 年 7.8 级凯库拉地震动态触发新西兰浅层慢滑事件的数值模拟
DOI：
10.1029/2018gl077879
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发表时间：
2018
影响因子：
5.2
通讯作者：
Liu, Yajing
中科院分区：
文献类型：
--
作者：
Wei, Meng;Kaneko, Yoshihiro;Shi, Pengcheng;Liu, Yajing
2016年凯库拉7.8级地震在希库朗吉俯冲带北方引发了广泛的慢滑事件（SSE），为研究SSE的动态触发机制提供了独特的机会。在这里，我们模拟了新西兰吉斯伯恩附近的SSE，在速率和状态摩擦的框架内。浅俯冲界面上的低有效正应力（~0.4 MPa）需要再现所观察到的重复自发的SSE。来自凯库拉主震的动态应力扰动足以触发具有与观测相似特征的SSE。SSE的动态触发倾向主要取决于扰动的时间相对于SSE周期和最大库仑应力变化。一旦扰动幅度超过初始阈值，长时间的应力扰动倾向于降低触发阈值，从而促进SSE的动态触发。因此，浅SSE更有可能是动态触发比深同行，因为增强应力扰动（幅度和持续时间）的沉积楔。
The 2016Mw7.8 Kaikoura earthquake triggered widespread slow slip events (SSEs) in the northern Hikurangi subduction zone, providing a unique opportunity to study the mechanism of dynamic triggering of SSEs. Here we simulate SSEs near Gisborne, New Zealand, in the framework of rate‐and‐state friction. Low effective normal stress (~0.4 MPa) on the shallow subduction interface is needed to reproduce the observed repeating, spontaneous SSEs. Dynamic stress perturbations from the Kaikoura mainshock are adequate to trigger SSEs with characteristics similar to observation. SSE propensity to dynamic triggering mainly depends on the timing of perturbation with respect to the SSE cycle and the maximum Coulomb stress change. Once the perturbation amplitude exceeds an initial threshold, prolonged stress perturbations tend to decrease the triggering threshold hence promote dynamic triggering of SSEs. Therefore, shallow SSEs are more likely to be dynamically triggered than their deep counterparts because of enhanced stress perturbation (magnitude and duration) from the sedimentary wedge.