1995年兵庫県南部地震での建物被害地域における人工衛星SAR強度画像の特徴

抄録

Satellite and airborne remote sensing, which can easily monitor a large area with high resolution, can provide effective spatial information to detect earthquake-induced damage. As a sensor installed on satellites JERS and ERS, synthetic aperture radar (SAR) is one of the most promising technologies since it is not affected by clouds. One of distinctive characteristics of SAR systems is their capability of recording both amplitude and phase of the backscattering echoes from objects on the earth's surface. In this paper, we investigated the microwave scattering characteristics of areas damaged by the 1995 Hyogo-ken Nanbu (Kobe) earthquake using ERS/SAR images for the purpose of possibility of extracting earthquake damage distribution by satellite SAR. According to the difference in backscattered intensity and spatial correlation of SAR images taken before and after the earthquake, we found that the characteristics of the backscattering properties of damaged areas showed significant variations. The relationship between building damage and the SAR images was found to be related to the damage level. This trend in areas of heavy building damage was revealed when the backscattered intensity and the correlation of pre- and post-event images became low. The damage distribution extracted by discriminant analysis based on backscattering properties agreed with the results of an actual damage survey. Therefore, the images obtained by remote sensing SAR could be a powerful tool for post-disaster management.