Reevaluation Method of Fragility Curves of Wooden House Based on Collected Damage Information

The distribution of earthquake damage plays an important role in the rescue operation and the restoration work in the aftermath of a seismic event. Immediately after an earthquake, the building damage ratios are estimated using ground motion indices and fragility curves constructed from the prior earthquake damage information. However, it should be noted that the fragility curves may sometimes provide less accurate estimations for recent earthquakes. On the other hand, some researchers are focusing efforts on collecting the actual damage information efficiently soon after an earthquake has occurred. The increased attention to collecting the actual damage information is expected to improve the efficiency in the near future and become increasingly helpful for a rapid disaster assessment. In this study, a method for data synthesis to restructure fragility curves is proposed, with respect to the actual gathered damage information. Either the mean or the standard deviation of the prior fragility curve is updated based on collected building damage datasets after recent earthquakes. As a result, the restructured fragility curves with the updated mean values show better estimations than the original ones.