Earthquakes as a coupled shear stress‐high pore pressure dynamical system
Earthquakes as a coupled shear stress‐high pore pressure dynamical system
复制标题
地震作为剪切应力-高孔隙压力耦合动力系统
DOI：
10.1029/95gl03178
复制
发表时间：
1996
影响因子：
5.2
通讯作者：
D. Olgaard
中科院分区：
文献类型：
--
作者：
S. A. Miller;A. Nur;D. Olgaard
利用孔隙度降低机制来模拟滑动、地震和高孔压带的迁移、合并和局部化，以在超过静水压的断裂带内驱动孔压。离散细胞中孔压的增加会产生低效应力区，这会导致滑移，根据局部应力状态，滑移可能会传播到周围的细胞。在滑移时，利用弹性半空间中矩形位错的解来传递应力，并通过守恒流体质量来重新分布孔压。在简单的断层流变性和渗透性假设下，剪应力和有效应力之间的相互作用演化为一种地震丛集状态，具有反复事件、闭锁带和断层强度变化较大的特点。该模型由强断层上的均匀剪应力状态演化为弱断层上的非均匀剪应力状态。
The migration, coalescence and localization of slip, seismicity, and zones of high pore pressure are modeled using a porosity reduction mechanism to drive pore pressure within a fault zone in excess of hydrostatic. Increased pore pressure in discrete cells creates zones of low effective stress, which induces slip that may propagate to surrounding cells depending on the local state of stress. At slip, stress is transferred using the solution for a rectangular dislocation in an elastic half-space, and pore pressures are redistributed by conserving fluid mass. Using simple assumptions about fault rheology and permeability, it is shown that the interaction between shear stress and effective stress evolves to a state of earthquake clustering with repeated events, locked zones, and large variations in fault strength. The model evolves from a uniform shear stress state on a strong fault, to a heterogeneous shear stress state on a weak fault.