Evolution of the full-interface shear stress of a fault during frictional instability

Abstract

In this paper, mechanoluminescent material is first developed to measure the full-interface shear stress of the fault. The luminous intensity of mechanoluminescent material during frictional instability is captured in real time, and its luminous intensity is calibrated by the rosette strain gauge to determine the shear stress of the fault. The experimental and numerical results show that the fault interface can be divided into shear stress-strengthening zone and shear stress-weakening zone. Moreover, the effects of the normal stress and impact energy on the shear stress of the fault interface are experimentally and numerically investigated, and the experimental and numerical results are consistent. Finally, the relationship between the stress state of the interface rupture front and the analytical solution of the shear crack in the framework of the linear elastic fracture mechanics is investigated. This study is helpful to explain the mechanism of shallow-focus tectonic earthquakes.