Quantitative relationship between aseismic slip propagation speed and frictional properties
Quantitative relationship between aseismic slip propagation speed and frictional properties
复制标题
DOI：
10.1016/j.tecto.2019.06.021
复制
发表时间：
2019-09-20
期刊：
影响因子：
2.9
通讯作者：
Hori, Takane
中科院分区：
文献类型：
--
作者：
Ariyoshi, Keisuke;Ampuero, Jean-Paul;Hori, Takane
最近的观测表明震后滑动传播的证据，其中可能包含有关断层的力学性质的信息。在这里，我们开发了一个新的分析之间的关系的传播速度的无源滑动瞬变和故障摩擦性能，建模的速率和状态相关的摩擦法。这种关系解释了三维数值模拟中后滑的传播速度到一阶。基于这种关系，我们确定了系统的依赖性的后滑传播速度的有效正应力σ和摩擦性能（系数a和a-b，分别量化的瞬时和稳态速度依赖性的摩擦，和故障状态演变的特征滑动距离L）。较低的参数A = a σ的值会导致更快的传播，在这些地区，震后滑动锋的通道会引起较大的剪切应力变化Δ τ相比，A，这通常是位于附近的主震破裂。在Delta tau/A很小的区域，通常离主震更远，后滑传播速度对（a-b）sigma更敏感。在加载跨度明显小于震后滑动通道的条件下，传播速度与初始滑动速度成正比，与L成反比。这里开发的关系应该是有用的，以约束摩擦性能的故障的基础上观察到的传播速度，独立的岩石实验室实验，然后可以用于预测数值模拟的asependentslip现象。
Recent observations show evidence of propagation of postseismic slip, which may contain information about the mechanical properties of faults. Here, we develop a new analytical relationship between the propagation speed of aseismic slip transients and fault frictional properties, modeled by a rate- and state-dependent friction law. The relationship explains the propagation speed of afterslip in 3-D numerical simulations to first order. Based on this relationship, we identify systematic dependencies of afterslip propagation speed on effective normal stress sigma and frictional properties (the coefficients a and a-b which quantify the instantaneous and the steady-state velocity -dependence of friction, respectively, and the characteristic slip distance L of fault state evolution). Lower values of the parameter A = a sigma cause faster propagation in areas where the passage of the postseismic slip front induces large shear stress changes Delta tau compared to A, which are typically located near the mainshock rupture. In areas where Delta tau/A is small, typically more distant from the mainshock, afterslip propagation speed is more sensitive to (a-b)sigma. The propagation speed is proportional to initial slip velocity and, under the condition that loading span is significantly shorter than the passage of postseismic slip, inversely proportional to L. The relationship developed here should be useful to constrain the frictional properties of faults based on observed propagation speeds, independently of rock laboratory experiments, which can then be used in predictive numerical simulations of aseismic slip phenomena.