Extraction of topographic features in landslide areas from ERS-1 SAR data

An analysis has been undertaken of characteristic features of the ERS-1 SAR image in areas where landslides may occur. First, statistical quantities of SAR data corresponding to landslide areas and non-landslide areas are computed for the study site (the Noto peninsula in Japan). As a result, it is shown that the difference of mean values of gray levels between landslide areas and non-landslide areas is of no significance. Moreover, the drainage system is extracted on the basis of the assumption that some streams will be defined by the dark strips caused by the combined effects of shadow and open water. It is found that the extracted drainage courses correspond to the dark strips that are visible on the SAR image as valleys