Effects of Barriers on Fault Rupture Process and Strong Ground Motion Based on Various Friction Laws
Effects of Barriers on Fault Rupture Process and Strong Ground Motion Based on Various Friction Laws
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DOI：
10.3390/app10051687
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
Jie Yuan;Jinting Wang;Shoubiao Zhu
中科院分区：
文献类型：
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作者：
Jie Yuan;Jinting Wang;Shoubiao Zhu
障碍物可能在断层上引起超剪切破裂。本文主要研究两个问题：一是障碍物的存在是否加速了整个断层破裂的传播速度；二是障碍物的摩擦规律和强度对破裂传播过程有何影响。为此，采用经典的滑移弱化、速率状态和修正的滑移弱化摩擦定律来模拟障碍对断层破裂过程的影响。模拟结果表明，当破裂锋向障碍体传播时，断层的破裂速度明显减慢，而当破裂锋离开障碍物时，破裂速度明显增加。研究还发现，断层上的势垒可以通过速率-状态摩擦定律引起超剪切破裂。模拟结果还表明，随着障碍物强度的增加，障碍物附近的破裂速度波动越来越大；当障碍物强度超过一定程度时，断层上出现了超剪切破裂区；随着障碍物强度的增加，超剪切波速下破裂的传播距离也相应增加。另外，随着障碍体强度的增加，断层的整体破裂持续时间略有增加。这表明，障碍不能缩短断层破裂的总持续时间。尽管障碍物会导致超剪切破裂，但它只是调节断裂速度在断层表面的分布。而且，随着障碍物强度的增加，通过障碍物破裂引起的地面峰值加速度也增加，表明障碍物的存在可能会导致地震灾害的加剧。
A barrier may induce a supershear rupture on a fault. This paper focuses on two questions: One is whether the existence of a barrier accelerates the propagation speed of a whole fault rupture, and the other is what are the effects of friction laws and strength of a barrier on the rupture propagation process. For these purposes, classical slip-weakening, rate-state, and modified slip-weakening friction laws are employed to simulate the effect of a barrier on the fault rupture process. The simulation results showed that the rupture speed of the fault obviously decreases when the rupture front propagates to the barriers, and the rupture speed obviously increases when the rupture front leaves barriers. It was also found that a barrier on a fault may induce a supershear rupture via the rate-state friction law. The simulation results also showed that with the increase of barrier strength, the rupture speed near barriers fluctuates more and more; when the barrier strength exceeds a certain level, a supershear rupture area appears on the fault; with the increase of barrier strength, the propagation distance of the rupture at supershear wave velocity correspondingly increases. In addition, with the increase of barrier strength, the overall rupture duration of the fault slightly increases. This indicates that a barrier cannot shorten the total duration of a fault rupture. Though a barrier will lead to a supershear rupture, it just regulates the distribution of the rupture speed on the fault surface. Moreover, with the increase of barrier strength, the peak ground acceleration caused by rupture through the barrier also increases, indicating that the existence of a barrier may lead to the intensification of seismic hazards.