Earth Planets Space, Vol. 57 (No. 4), pp. 345-350, 2005LETTER
Wataru Suzuki, Tomotaka Iwata, Kimiyuki Asano, and Nobuyuki Yamada
Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
(Received December 3, 2004; Revised March 15, 2005; Accepted April 7, 2005)
We estimated the source model for the foreshock of the 2004 off the Kii peninsula earthquakes by empirical Green's function modeling. The size and the rise time of the strong motion generation area (SMGA) were estimated to be 30 × 15 km, and 0.9 sec, respectively. The stress drop of the SMGA was calculated to be 8.3 MPa. This model could reproduce long-period ground motions following the direct S-wave observed in the Osaka basin well. Using the derived source parameters, we simulated strong motions of the hypothetical Tonankai earthquake. Distribution of the seismic intensity derived here is similar to that obtained by the previous report. We could predict long-period ground motions which last for a long duration at the basin sites.
Key words: Empirical Green's function method, foreshock of the 2004 off the Kii peninsula earthquakes, source model, stress drop, strong ground-motion simulation, hypothetical Tonankai earthquake.