Source Radiation Pattern Database Calculated from the 1-D Seismic Velocity Structure in Taiwan

Source Radiation Pattern Database Calculated from the 1-D Seismic Velocity Structure in Taiwan

The National Center for Research on Earthquake Engineering hosted the Senior Seismic Hazard Analysis Committee Level III project in Taiwan (NCREE, 2018) and rearranged the ground motion database and flat-file in the ground motion characteristics (GMC) team. The flat-file was built in an attempt to develop spectral acceleration based ground motion models (GMM) for application to seismic hazard evaluation. However, some complex effects or indices were not considered or calculated in the database and still require careful consideration. These include the Fourier amplitude spectrum, and hanging wall, directivity, seismic duration, and radiation pattern effects. In this study, to update the ground motion database in Taiwan, the necessary information from the GMC flat-file is gathered to upgrade systematically the applicability of the database. The theoretical source radiation pattern is calculated from the pseudo-bending ray-tracing method in a three-dimensional grid and the one-dimensional velocity structure for each record in the Taiwanese database. Specifically, takeoff angles and S wave radiation coefficients were added to the database for each record for future applications in GMM in Taiwan.