Vibration-induced slip in sheared granular layers and the micromechanics of dynamic earthquake triggering

We perform 2D Molecular Dynamics simulations of sheared granular layers in the presence of applied vibration. A primary goal is to understand the physics of dynamic earthquake triggering. We adopt a mesoscopic measure of non-affine deformation for characterizing the granular dynamics during slip without or with applied vibration. Our results show that the onset of non-affine strains correlates with the onset of slip and appears earlier in the presence of vibration than in its absence, in agreement with the evidence for triggered slip.