The Attenuation Field in the Focal Zone of the 2003 Altai Earthquake, Using the Coda Envelopes of the Aftershocks

摘要

The results of the study of the field of shear-wave attenuation in the focal zone of the 2003 Altai earthquake using a short-period coda method are presented. The attenuation field of the Altai earthquake focal zone includes blocks with a high Q-factor and linear weakened zones. During the main shock, surface rupture is confined to the zone of strong attenuation. The epicenters of the main shock and its two strongest aftershocks are located in the zones of maximally contrasting shear-wave attenuation in the Earth's crust and the upper mantle. The subcrustal fluid-saturated layer here is characterized by high viscosity, which is apparently the reason for the relatively low level of seismic activity in the Altai.