Use of GIS to Assess Susceptibility per Landform Unit to Gravitational Processes and their Volume

Abstract

AbstractLandslide susceptibility per landform unit and its potential contribution of material was calculated for a 105 km2 watershed on the south flank of Pico de Orizaba volcano, Mexico. More than six hundred landslides were mapped and grouped into landform units. Fifteen landform units were derived from fieldwork, aerial photo interpretation, land use, and morphometric parameters. For each landform, landslide susceptibility was calculated from the area and frequency of landslides. Volume calculation used a surface area-volume power law from geometric values of shallow landslides. Support by Geographic Information Systems created a comprehensive method. Although most landslides were in volcanic landform units, those in sedimentary units contributed more sediment per square kilometer. The study shows that landform units can be used to explain the predisposition and variability of landslide sediment production for a large and complex geological watershed.