人工衛星SAR強度画像を用いた被害地域検出手法の最近の地震への適用とその妥当性の検討

概要

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The 1994 Northridge and the 1995 Kobe earthquakes realized us the importance of grasping damage information on built-up areas in the early stage for recovery activities and restoration planning. One of the remarkable characteristics of synthetic aperture radar (SAR) is its capability of recording the physical value, called the backscattering coefficient, of the earth's surface under independence of weather condition and sun illumination. Therefore SAR could be a powerful tool and possibly be used to develop a universal method for grasping damaged areas during disasters such as earthquakes, forest fires and floods. Detailed ground truth data with building damage due to the 1995 Kobe earthquake provided us the opportunity to examine the relationship between the backscattering property and degree of damage. From the above analysis we have already developed a method to detect areas of building damage. In this paper, we introduced the automated detection method using the average difference in the backscattering coefficient and the spatial correlation derived from the pre- and post-event speckle-reduction-filtered images. Then we applied this method to the images taken over the area hit by the 1993 Hokkaido Nansei-Oki, Japan, the 1999 Kocaeli, Turkey, and the 2000 Gujarat, India earthquakes, and then the accuracy of the proposed method was examined by comparing the results of the analyses with those from the damage surveys.
2002-08-30