Project Abstract
|
Unraveling the governing laws behind rupture dynamics within seismic cycles is imperative for advancing earthquake prediction. However, the choice of a theoretical framework remains ambiguous. Fracture mechanics provides an integrated description of rupture characteristics based on the energy balance at the crack tip and a posteriori knowledge of the strength versus slip profile. In contrast, empirical friction laws provide a point-wise description of the constitutive behavior that reproduces many natural observations, albeit with unclear physical origins. Here, we use velocity-step and dynamic rupture experiments on transparent materials to show that a physical model of the slip-rate and state dependency of frictional sliding based on the real area of contact reconciles and explains both frameworks. We compare laboratory observations with numerical simulations spanning all phases of the seismic cycle, including the propagation of seismic waves. The model not only captures the source characteristics of dynamic ruptures, such as rupture velocity and stress drop, but also reproduces the evolution of light transmitted across the frictional interface during seismic ruptures. The physical assumptions explain the origin of the slip-rate and state dependency of friction and lead to a linear slip-weakening model under particular parametric configurations relevant to dynamic ruptures, compatible with principles from fracture mechanics. Continuous measurements of the state of a fault during seismic cycles emerge as a novel tool for advancing our understanding of the earthquake phenomenon. |
