Detection method of slope failures due to the 2009 sumatra earthquake by using TerraSAR-X images

This paper describes a slope failure detection method by using high resolution SAR satellite images when the disaster occurs. We have proposed the detection method of slope failures by using the optical sensor image in such a situation. The optical sensor images are not applied to observe the ground surfaces if the clouds cover the suffered area. On the other hand, the SAR images are effective for the cloudy whether because the micro wave passes the clouds. Therefore, the SAR image can be used for an urgent observation when the disaster occurs. When the remote sensing image is applied to disaster prevention, the concept of time is important. It is demanded to understand the outline of damage immediately after the occurrence of the earthquake. In this research, we proposed a slope failure detector using high resolution SAR satellite (TerraSAR-X (TSX) and TanDEM-X (TDX)) images. The proposed method was applied to the detection of large number of earthquake induced slope failures in the Padang Pariaman prefecture triggered by the 2009 Sumatra earthquake in West Sumatra, Indonesia. The conclusions are shown as follows. (1) The case of two time series TSX image was used, the main scape was possible to distinguish easily by using color composite image. (2) When the TSX image after the earthquake and local incidence angle were used, the main scape was able to be detected by the accuracy of about 65%. (3) InSAR analysis was done by using TDX image after the earthquake, and clear interferogram appeared in slope failure area. Therefore, the InSAR analysis was effective to the detection of slope failures.