Evaluation of site amplification factors using seismic observation and miniature array analysis of microtremors for damage estimations in Zushi City

According to previous studies and damage investigations after large earthquakes, the distribution of earthquake damage is different in each region, so in disaster management plan, it is important to understand dynamic characteristics of ground in detail. However, most of seismic hazard maps in Japan employ site amplification factors obtained from the engineering geomorphologic classification database and hence the accuracy of the ground motion estimations during earthquakes is not sufficient. In this study, therefore, to obtain high resolution seismic hazard map with higher accuracy, we have conducted high density seismic observation and microtremor miniature array measurements in Zushi City, Kanagawa, Japan. We have estimated site amplification factors using seismic observation data and microtremor miniature array measurements, and seen there is correlation between them. As the results, in Zushi City, site amplification factors vary even in small area, and site amplification factors estimated using seismic observation and microtremor miniature array measurements have good correlation if the stations are located within 50m. Furthermore, we have obtained seismic intensity maps and building damage risk maps for the Southern Tokyo Inland Earthquake and the Earthquakes along the Miura Peninsula Faults using seismic observation and microtremor miniature array measurements with higher resolution compare with conventional damage estimations.