Detection of the Flooded Area by Tsunami Using Satellite Thermal Infrared Images

Heavy casualties and severe property losses occurred by the tsunami in the Off Pacific Coast of Tohoku, Japan Earthquake on March 11, 2011. Satellite visible images are easy to grasp damages caused by disasters, but they cannot be obtained in nighttime. Hence a blank time of information may occur if a disaster happens in nighttime. On the other hand, a satellite thermal infrared image can be taken in nighttime while it has an inferior spatial resolution. It is also expected to grasp flooded areas by tsunami using the temperature distribution from thermal infrared band images. In this study, the extraction of flooded areas was carried out by superimposing ASTER thermal infrared band images captured before and after the Tohoku earthquake, obtaining the difference in temperature. This result was compared with the flooded area map that was created by the interpretation of aerial photos and site investigations. The comparison shows a reasonably good agreement although the times of acquiring the post-event images were not the same. A further improvement of flooded area extraction may be achieved by introducing land-cover information and DEM data.