Landslide hazard assessment in the Three Gorges area, China, using ASTER imagery: Wushan–Badong

The objectives of this study are to develop a methodology for regional scale assessment of landslide hazard using remotely sensed data, and to produce a landslide hazard map of the Wushan–Badong area in the Three Gorges, China, from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images. The area is undergoing rapid urban development, with slope instability causing a widespread natural hazard. Landslide-related parameters were largely estimated through image processing and visual interpretation of ASTER multi-spectral and topographic data. We used field measurements to define the quantification for three parameters: (a) slope angle in relation to lithology; (b) distance to drainage network in relation to stream order; and (c) distance to tectonic lineament in relation to lineament length. We employed a multi-parameter elimination and characterization model, based on estimation of the geometric mean, to remove areas where landslides are not expected to occur, and classify the remaining areas into landslide hazard categories. Our results show increased landslide hazard in and around Wushan and Badong Towns, as well as other populated areas along the Yangtze and its tributaries. We used field data on landslide distribution to identify typical geomorphological settings for different landslide types, and to provide ground control for the hazard assessment. The results indicate good correlation between classified high-hazard areas and field-confirmed slope failures, and show the usefulness of ASTER imagery for landslide hazard assessment at a regional scale.