Slip-behavior transitions of a heterogeneous linear fault
Slip-behavior transitions of a heterogeneous linear fault
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异质线性断层的滑动行为转变
DOI：
10.1002/2016jb013132
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
and S. Ide
中科院分区：
文献类型：
--
作者：
Yabe;S.;and S. Ide
地质断层具有摩擦非均匀性。在这里，我们在最简单的情况下研究这种非均匀断层的滑动行为，在二维弹性模型空间中模拟沿着无限线性断层的反平面剪切滑动，并受到以刚度和板块运动速度为特征的外部应力的恒定载荷。断层被离散为许多子断层，每个子断层都具有速度减弱（VW）或速度加强（VS）摩擦规律。我们改变断层的比例，是大众，揭示了几个不同的制度的滑动行为。粘滑行为开始的第一状态边界位于VW区的比例处，使得每个VW区达到其成核尺寸。另一个边界位于速率和状态摩擦定律的空间平均da − b值接近于零的地方。低于这个密度，VW区地震滑动，而VS区显示后滑。相反，在此密度以上，整个断层以地震滑动速度同时滑动。我们观察到过渡行为在第二个边界，相对较慢的变形占主导地位。我们还使用摩擦参数的Cantor集分布探索断层的滑动行为。我们认为，断层上的摩擦不均匀性不仅可以解释地震现象的多样性，还可以解释所观察到的摩擦参数的缩放，例如滑动弱化距离或普通地震的断裂能。
Geological faults have frictional heterogeneity. Here we investigate the slip behavior of such heterogeneous faults in the simplest situation, simulating antiplane shear slip along an infinite linear fault in a 2‐D elastic model space, subjected to constant loading by external stresses characterized by stiffness and plate‐motion velocity. The fault is discretized into many subfaults, each of which has either a velocity‐weakening (VW) or velocity‐strengthening (VS) friction law. We vary the proportion of the fault that is VW, revealing several different regimes of slip behavior. The first regime boundary, where stick‐slip behavior is initiated, is located at the proportion of VW zones such that each VW zone reaches its nucleation size. The other boundary is located where the spatially averageda−bvalue of the rate and state friction law is close to zero. Below this density, the VW zone slips seismically, whereas the VS zone shows afterslip. In contrast, above this density, the entire fault slips simultaneously at the seismic slip velocity. We observe transitional behavior at the second boundary, where relatively slower deformation dominates. We also explore the slip behavior of faults using Cantor‐set distributions of frictional parameters. We propose that frictional heterogeneity on the fault may explain not only the diversity of seismic phenomena but also the observed scaling of frictional parameters, such as slip‐weakening distance or the fracture energy of ordinary earthquakes.