Abstract Stick-slip failure, as a possible mechanism for destructive shallow focus earthquakes, often occurs in heterogeneous faults. To investigate the physical processes of stick-slip failure in heterogeneous faults, direct shear tests are performed in the laboratory, combined with the use of multi-channel high-speed dynamic strain acquisition system, on the bimaterial samples. The bimaterial samples consist of PMMA (poly methyl methacrylate) and PC (poly carbonate). This experimental study is concerned with the effects of fault roughness on the stick-slip behaviors along the heterogeneous faults. The metallographic microscope is used to quantitatively measure the surface morphology of the heterogeneous faults. The stress distribution along the simulated fault is highly non-uniform, which dictates the initiation locations of stick-slip failure. The nucleation starts at a firstly-yielded material point, and as the energy accumulation in the heterogeneous fault, the nucleation zone is progressively formed. The crack tip propagates at an increasing velocity until the entire fault is penetrated. It is found that a rougher fault is corresponding to a slower rupture velocity, a smaller local stress drop, a larger critical slip-weakening displacement, and a larger critical crack length.

中文翻译：

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不同断层粗糙度的非均质剪切断层中的粘滑破坏

摘要 粘滑破坏作为破坏性浅源地震的一种可能机制，常发生在非均质断层中。为了研究非均质断层中粘滑破坏的物理过程，在实验室中进行了直剪试验，结合使用多通道高速动态应变采集系统，对双材料样品进行了测试。双材料样品由 PMMA（聚甲基丙烯酸甲酯）和 PC（聚碳酸酯）组成。本实验研究涉及断层粗糙度对沿非均质断层粘滑行为的影响。金相显微镜用于定量测量非均质断层的表面形貌。沿模拟断层的应力分布高度不均匀，这决定了粘滑破坏的起始位置。成核从最先屈服的物质点开始，随着能量在非均质断层中的积累，成核区逐渐形成。裂纹尖端以增加的速度传播，直到穿透整个断层。发现越粗糙的断层对应于较慢的破裂速度、较小的局部应力降、较大的临界滑移弱化位移和较大的临界裂缝长度。