Development of a loading and diagnostic system to study laboratory earthquakes

Studies on spontaneous rupture mechanisms are limited because using existing experimental apparatuses is difficult to accurately observe parameters related to the rupture (e.g., slip history and frictional properties of fault). This study proposes multiple diagnostic systems combined with a biaxial loading device to study the rupture mechanism. Two isosceles right triangle PMMA plates are held together to form a fault model. The spontaneous rupture is achieved under various friction angles through different combinations of the x-axis and y-axis loading forces. A digital image correlation (DIC) method is systematically used to measure displacement and stress fields along the fault during rupture, thus accurately quantifying rupture velocity and stress distribution. Accelerometers are used to measure seismic waves. In this experiment, the supershear rupture can be detected, and the potential energy and the energy consumed are discussed. Typical results prove the feasibility and flexibility of the proposed system.