HEAVY RA INFALL-INDUCED LANDSLIDE DETECTION FROM VERY HIGH RESOLUTION MULTI-ASPECT TERRASAR-X IMAGES IN DESSIE, ETHIOPIA

The impact of landslide is enormous in towns adjacent to the rift escarpments and highlands of Ethiopia, especially in rainy seasons. To study the seasonal variation and trend of slope instability in these areas with support of the current radar technology, 40 spotlight mode of TerraSAR-X/TanDEM-X (TSX/TDX) radar imageries were acquired from German Aerospace Agency (DLR). The conventional 2-pass DInSAR method has been applied to process the SAR data, and the DInSAR time series analysis result obtained by stacking 11 and 22 days interferograms from both ascending and descending orbits showed that there are 2-3 cm mass movements or deformation in the rainy season and 1-2 cm in the dry months. The results obtained from the DInSAR analysis were compared with a landslide inventory map containing more than 20 active landslides of the area of interest, and generally a good consistency was observed.