Abstract
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 at nighttime. Hence a blank time of information may occur if a disaster happens at nighttime. On the other hand, satellite thermal infrared images can be taken at nighttime although it has an inferior spatial resolution. Thermal infrared images are also expected to grasp flooded areas by tsunami using the temperature distribution. This study extracted the flooded areas from ASTER thermal infrared images by calculating the difference in temperature before and after the earthquake. The examples of the extraction method were demonstrated for Soma and Ishinomaki cities, where significant tsunami damages were observed. The results were compared with ASTER false-color composite images and the inundated area map created by Geospatial Information Authority of Japan (GSI) to evaluate the accuracy of the proposed method. These comparisons show reasonable agreement of flooded areas with the daytime optical images and the GIS map. The extraction results were also compared with the distribution of the normalized difference vegetation index (NDVI) and high correlation between them was observed.
