Abstract
Large part of urban area of Kobe, Ashiya and Nishinomiya city were damaged by the 1995 Hyogoken-nanbu earthquake. The authors attempted to detect their damages by ERS-1/SAR intensity images. The intensity images obtained before the earthquake indicated urban structure clearly, however, the structural pattern was unclear in the images after the earthquake. Norm type correlation coefficients of data pair between before and after the earthquake indicated decorrelation at damaged urban area. The decorrelation by the earthquake was detected obviously in comparison with the correlation of the data pairs which interval did not include the earthquake occurrence. The areas where the backscatter correlation changed significantly before and after the earthquake correspond to damaged built-up areas observed by aerial photographs. The ground surface change by the earthquake, such as collapse or burnt down of buildings, should cause the change of backscatter characteristics and further study is necessary to investigate its mechanism. Collapsed built-up area has not been recognized by optical sensor images like SPOT/HRV. The result of this study suggests the usefulness of SAR intensity images for urban disaster observation.
