5:15 PM - 6:30 PM
[SSS25-P01] Estimation of source model of the 1931 NISHI-SAITAMA earthquake using long-period ground motion at Hongo in Kanto basin
Keywords:The 1931 Nishi-Saitama earthquake, long-period seismogram, focal depth
In this study, we tried to estimate a source model of the 1931 Nishi-Saitama earthquake by comparing a long-period seismogram observed in Hongo, Tokyo, which is the only seismogram recorded completely in the Tokyo Metropolitan area with synthetic seismograms simulated by a 3D finite differential method considering recent detailed model of the Kanto basin. It is clarified that the main part of the observed long-period seismogram is composed of surface waves affected by the three-dimensional effect of the sedimentary layers in the Kanto basin. We also found good agreement between the calculated and observed seismograms, when the depth of the source fault is set to be in a range of 20-30 km with a rupture propagating from the bottom edge of the center of the fault.