Abstract
According to the analysis of seismic observation records, the site characteristics of strong motions at engineering base layer in Kanto region show the regionality. We have been conducted numerical simulation analyses to understand the reason of this phenomenon. Our tentative view of the reason is due to the amplification effects generated by the deep ground structure. In this study, the validity of 3D FEM numerical simulation was investigated with comparing the calculated results to the observation record. At the same time, parametric study was carried out in order to obtain the optimum source model. Then, the correction of calculated ground motion with respect to distance attenuation was performed to examine the quantitative spatial characteristic of simulation results. The attenuation relation model of ground motions at engineering base layer was developed by using the observation records in the target area. Quantitative investigation with respect to the mechanism to produce the regional site effects on seismic ground motion at engineering base layer in Kanto region was implemented by the process mentioned above.
