A scaling law for earthquakes and fault rheology

摘要

An earthquake has been regarded as the sudden slip of a fault or a plate boundary. However, the recent observations reveal that much slower slip is also ubiquitous. One of the most illustrating examples is the "slow slip", which takes place during several months. A natural question might be; what determines the nature of slip? This question involves the physical law of friction, which we still do not fully understand. In particular, the nature of friction on a fault involves rheology of rock powder, because a fault consists of layers of fine rock grains that are ground-up by the fault motion of the past. Here we numerically investigate the nature of granular friction focusing constitutive laws for both stable and unstable sliding.