Stress drop and fractional heating during the 1994 deep Bolivia earthquake

Abstract

We use the slip model of the Bolivian earthquake obtained by Ihmlé [1998] to investigate the spatial distribution of stress drop and calculate the frictional heat generated locally on the fault. We find that the stress drop associated with the earthquake averages between 5 and 10M Pa over the fault. The total frictional energy is estimated at between 3×1017 and 2×1018 J. If the fault width is as thin as the one produced by transformational faulting in laboratory experiments, where it is about two orders of magnitude smaller than the local shear displacement, melting likely occurred on a significant portion of the fault. In this event, as proposed by Kanamori et al. [1998], once rupture is triggered, shear melting can quickly promote extensive slip. Copyright 1999 by the American Geophysical Union.