Distribution of dynamic and static stress changes during 2000 Tottori (Japan) earthquake: Brief interpretation of the earthquake sequences; foreshocks, mainshock and aftershocks

Abstract

The dynamic and static stress changes during the 2000 Tottori earthquake have been recovered from the results of waveform inversion. We use the DEM to solve the elastodynamic equation specifying the slip along the fault obtained by a kinematic fault model. The resulting shear stress distribution suggests an explanation of the foreshock and aftershock distributions. We conclude that the fault zone heterogeneity is strong and most of the foreshocks and aftershocks were located in the zone of negative stress drop and mainly in the area surrounding the asperity. This suggests that the asperity behaved as a barrier during the foreshocks and after the main shock the stress in the area surrounding the asperity increased and triggered most of the aftershocks. The foreshock distribution was confined to a finite localized zone in the central part of the fault, suggesting that this zone was bordered by barriers.