Modeling strong motion in the Ashigara Valley for the 1990 Odawara, Japan, earthquake

Finite-difference seismograms are calculated for the 1990 Odawara earthquake. Using a basin structure derived from a geotechnical survey and a double-couple solution determined from the P first-motion data, a two-dimensional SH finite-difference calculation reproduces the observed spatial variation in amplitude and waveform of the transverse records at the Ashigara Valley Blind Prediction sites for Frequencies lower than 2 Hz. Comparison of the synthetics and the observed seismograms suggests that the observed amplitude variation of the transverse records in the Ashigara Valley is mainly due to the source radiation pattern rather than the basin structure. -from Authors