From earthquake centroid to spatial‐temporal rupture evolution: Mw 6.3 Movri Mountain earthquake, June 8, 2008, Greece

Abstract

We propose a new strategy to reveal the spatial‐temporal evolution of the earthquake rupture process from near‐regional data, without assuming a constant rupture velocity. The approach is based on a conjugate gradient method, for which we express analytically the required waveform‐misfit derivative with respect to slip on the fault. The derivative is given by back‐propagation of residual seismograms towards the source. A good initial source approximation is necessary, being obtained from hypocenter location and centroid‐moment tensor solution. The iterative approach then gradually reveals major characteristics of the source process. As an application, we investigate a line source model of a damaging Mw6.3 earthquake in Greece, revealing predominantly unilateral rupture propagation and two or three main slip patches, one of which being significantly delayed, indicating a temporary rupture arrest. The region of largest slip coincides with the region of least abundant aftershocks between hypocenter and centroid. The method has application potential for shakemaps, emergency response, and/or aftershock hazard assessment.