Effects of Humidity, Shear Stress, and Strain Rate Localization on Fault Healing and Friction

地震周期要求断层在两次地震之间再次加强。摩擦愈合（在准静止接触过程中增加静摩擦）被认为是最可能的震间强度恢复机制。然而，人们对摩擦愈合的机制了解甚少。本研究旨在研究模拟颗粒状断层泥断层愈合和摩擦老化的物理化学机制。实验结果将对理解时间依赖和滑移依赖的摩擦演化之间的区别具有重要意义。最近关于动态破裂的理论研究表明，这种区别在确定地震特征方面起着关键作用，例如频率-震级尺度和破裂扩展模式（作为经典的自相似裂纹或自愈合滑动脉冲）。因此，这些结果将以一种重要的方式与震源物理学的其他研究联系起来，包括基于理论的研究和基于实地观测的研究。

Marone EAR-0001215 The seismic cycle requires that faults re-strengthen between earthquakes. Frictional healing (as evidenced by increasing static friction during quasi-stationary contact) is considered the most likely mechanism of interseismic strength recovery. However, the mechanisms of frictional healing are poorly understood. This proposal is to study the physical and chemical mechanisms of fault healing and frictional aging in simulated granular fault gouge. The results of the experiments will have significant implications for understanding the distinction between time- and slip-dependent friction evolution. Recent theoretical studies of dynamic rupture indicate that this distinction plays a key role in determining seismic characteristics such as frequency-magnitude scaling and the mode of rupture expansion (as a classical, self-similar crack or a self-healing slip pulse). Thus, the results will connect in an important way to other studies of earthquake source physics including theoretically-based studies and those based on field observations.