Linking fault morphology to its mechanical properties in laboratory experiments may shed some light on analyzing the seismogenic potential of a natural fault. Many previous experiments suggested that increasing the roughness of a polished fault tends to stabilize the fault. Furthermore, the roughness of faults, both experimental and natural, spontaneously evolves during slip. Here, we investigate the effects of the polished roughness and the post-slip roughness on experimental fault stability. The experiments were conducted on a granodiorite fault under initial normal stresses of 5–6 MPa and total slip distances of 1.5–2.5 mm. The results reveal that the polished fault with a higher roughness exhibits stick-slip, while the post-slip fault with a lower roughness exhibits stable slip. Moreover, a decrease in the roughness of a post-slip fault tends to stabilize the fault. The monitored macroscopic loading data indicate that the critical slip distance is significantly greater in a post-slip fault than in a polished fault. These results imply that the critical slip distance of young, rough faults may evolve dramatically with slip, subsequently affecting the fault stability.

中文翻译：

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抛光粗糙度和后滑移粗糙度对断层稳定性的不同影响

在实验室实验中将断层形态与其机械特性联系起来可能有助于分析自然断层的发震潜力。先前的许多实验表明，增加抛光断层的粗糙度往往会稳定断层。此外，断层的粗糙度，无论是实验断层还是自然断层，都会在滑动过程中自发演化。在这里，我们研究了抛光粗糙度和后滑移粗糙度对实验断层稳定性的影响。实验在花岗闪长岩断层上进行，初始正应力为 5-6 MPa，总滑移距离为 1.5-2.5 mm。结果表明，粗糙度较高的抛光断层表现为粘滑，而粗糙度较低的后滑断层表现为稳定滑移。此外，滑移后断层粗糙度的降低往往会使断层稳定。监测的宏观载荷数据表明，后滑断层中的临界滑移距离明显大于抛光断层中的临界滑移距离。这些结果意味着年轻、粗糙断层的临界滑移距离可能会随着滑移而急剧变化，从而影响断层的稳定性。