Rupture speed and slip velocity: What can we learn from simulated earthquakes?

In this paper we consider a wide catalog of synthetic earthquakes, numerically modeled as spontaneous, fully dynamic, 3-D ruptures on extended faults, governed by different friction laws, including slip-dependent and rate- and state-dependent equations. We analyze the spatial correlations between the peak of fault slip velocity (vpeak) and the rupture speed (vr) at which the earthquake spreads over the fault. We found that vpeak positively correlates with vr and that the increase of vpeak is roughly quadratic. We found that near the transition between sub- and supershear regimes vpeak significantly diminishes and then starts to increase again with the square of vr . This holds for all the governing models we consider and for both homogeneous and heterogeneous configurations. Moreover, we found that, on average, vpeak increases with the magnitude of the event (vpeak ~ M00.18). Our results can be incorporated as constraints in the inverse modeling of faults.