Relationship between coseismic slip and static stress drop of similar aftershocks of the 2007 Noto Hanto earthquake Seismology

Abstract

We have investigated the spatial distribution of the static stress drop of similar aftershocks of the 2007 Noto Hanto earthquake, central Japan, and have examined the relationship between the coseismic slip of the mainshock and the static stress drop of the similar aftershocks. The static stress drop is estimated by using the empirical Green's function method for P- and S-waves. The estimated static stress drop approximately ranges from 5 to 20 MPa, which is a typical range of values for tectonic earthquakes. The static stress drops of the aftershocks in a large slip area of the mainshock tend to be larger than those in a small slip area. This suggests a large difference between the strength and the dynamic stress level in the large slip area and a small difference in the small slip area if the final stress level is equal to the dynamic stress level.