Application of high-resolution satellite images to detailed landslide hazard assessment

The study investigates and demonstrates the state of the art in remote sensing techniques for detailed landslide hazard assessment over large areas using (i) single and (ii) stereo satellite images from IKONOS Very High Resolution (VHR) sensor. The image fusion technique provides the ability for detailed landslide interpretation using single image and this is comparable to that obtainable from 1:10,000 scale air photos. The Pan-sharpening method of image fusion permits most of the qualitative (spatial and spectral) parameters used in air photo interpretation to be available on satellite images. For more detailed investigation such as the evidence of shadow, positional relationships to streams and ridges, stereoscopic viewing using a pair of stereo-images can be used. The DEM created from IKONOS stereo images appears to be much more accurate, and sensitive to micro-scale terrain features, than a DEM created with digital contour data with 2m contour interval, when both are compared with a high resolution photogrammetric model. This terrain sensitivity permits interpretation of recent landslides, as small as 2-3m in width on pan-sharpened, stereo IKONOS images, as well as relict landslides over 50 years old.