SAR Image Techniques for Mapping Areas of Landslides

Abstract
This paper shows that InSAR perspective view and airborne InSAR images are very useful for geomorphic characterization of landslide features in high relief terrains. Landslides cause approximately 1000 deaths a year, worldwide, with property damage of about US $4 billion. Developing new remote sensing techniques to identify and characterise landslides and debris flows will assist in the current national landslide inventory and hazard mapping in mountainous areas. Geomorphic characterization using large scale air photos are essential for large scale landslide hazard zonation maps. This is effectively done from the interpretation of large scale stereo air photographs and field mapping. In this study, we report on the use high-resolution airborne InSAR and perspective visualization techniques to map detailed landslide features in high relief terrains. We also show that high resolution fine mode (8m) RADARSAT image (40-50 degrees), although not as useful as the airborne InSAR images, can be used to identify some landslide features, thereby assisting in hazard mapping. The SAR image techniques provided information on detail slope profiles of the large rockslides occurring on steep slopes and along faults. From the images, faults, rock slumps, block slides, slide scars and debris slopes and ridges were identified. This study points the way of the potential of using high resolution optical and SAR stereo images to identify landslide features in areas where air photos are not readily available.