ABSTRACT
Authors have conducted seismic risk evaluation for individual facilities and for portfolios of facilities for years. Through the evaluations, it was pointed out that there is a gap between estimated loss and actual loss in case of real earthquake disasters. The gap is given by some causes, such as an error in ground motion prediction, one in vulnerability of facilities and one in damage ratio, and so on. Among the causes, authors focus on the aftershocks since there was a large gap between losses in case of 2016 Kumamoto earthquake, when series of large earthquakes hit the site and caused large disaster. In order to conduct realistic risk evaluation, authors have developed the procedure based on multi event model for risk evaluation considering aftershocks by adding following two features; (1) generating the conditional aftershock events, and (2) reducing the capacity of buildings reflecting damage status by main shock event.
