Structural vulnerability in the affected area of the 2011 Tohoku earthquake tsunami, inferred from the post-event aerial photos

Using the aerial photos published by Geospatial Information Authority of Japan (GSI), the authors visually inspected the building damage to identify the structural vulnerability in the tsunami affected area due to the 2011 Tohoku earthquake tsunami. First, the electronic map of buildings and the aerial photos were superimposed on GIS. Then, visual inspection of building damage was conducted in Iwate and Miyagi Prefectures, and in order to identify the structural vulnerability in each municipality, damage probabilities(P_D) were calculated by taking a ratio of the number of devastated buildings those were washed away over the number of total buildings exposed by the tsunami. Finally, the relationship between the number of devastated buildings and the number of fatalities were discussed to identify local vulnerability against the tsunami.