Precursory Stress Changes and Fault Dilation Lead to Fault Rupture: Insights From Discrete Element Simulations
Precursory Stress Changes and Fault Dilation Lead to Fault Rupture: Insights From Discrete Element Simulations
复制标题
DOI：
10.1029/2018gl081007
复制
发表时间：
2019-03
影响因子：
5.2
通讯作者：
D. Blank;J. Morgan
中科院分区：
文献类型：
--
作者：
D. Blank;J. Morgan
我们使用离散元方法来创建数值模拟俯冲巨型逆冲断层与自然粗糙度和非均质断层摩擦。边界条件模拟构造载荷，诱导断层滑动。间歇性地，滑动发展成复杂的破裂事件，包括前震，主震和余震。我们探讨断层带的运动学和应力演化，以深入了解这些现象的物理过程。长期的，局部的差应力下降之前的动态故障，一种现象，我们归因于逐步解锁的接触断层扩张破裂前。滑动稳定性在我们的系统似乎主要是由几何现象，这使得缓慢和快速滑动发生在同一地区沿着故障。模拟断层和真实的俯冲带之间滑动行为的相似性证实了模拟的物理过程也在自然界中起作用。
We use the discrete element method to create numerical analogs to subduction megathrusts with natural roughness and heterogeneous fault friction. Boundary conditions simulate tectonic loading, inducing fault slip. Intermittently, slip develops into complex rupture events that include foreshocks, mainshocks, and aftershocks. We probe the kinematics and stress evolution of the fault zone to gain insight into the physical processes that govern these phenomena. Prolonged, localized differential stress drops precede dynamic failure, a phenomenon we attribute to the gradual unlocking of contacts as the fault dilates prior to rupture. Slip stability in our system appears to be governed primarily by geometrical phenomena, which allow both slow and fast slip to take place at the same areas along the fault. Similarities in slip behavior between simulated faults and real subduction zones affirm that modeled physical processes are also at work in nature.