Extraction of damaged buildings due to the 2011 Tohoku, Japan earthquake tsunami

The 11 March 2011 Tohoku, Japan earthquake caused gigantic tsunamis and widespread devastations. Various satellites quickly captured the details of affected areas, and were used for emergency response. In this study, high-resolution pre- and post-event TerraSAR-X (TSX) intensity images were used to identify damaged buildings. Since the damaged buildings show changes in backscattering intensity, they can be detected by calculating the difference. A GIS map was introduced to identify individual damaged buildings and investigate their characteristics. According to the side-looking nature of SAR sensors, the buildings´ shapes obtained from the GIS map were converted to match their locations in the TSX images. Then washed-away and damaged buildings were extracted using the changed area of SAR intensity within a building´s wall and outline. The results were compared with visual interpretation results, and the accuracy of the proposed method was confirmed.