Preparing a Detailed Landslide-Inventory Map for Hazard Evaluation and Reduction

A method of preparing a detailed landslide-inventory map has been developed which provides the engineering geologist with the basic information for evaluating and reducing landslide hazards or risk on a regional or community level. For each landslide, the map depicts state of activity, certainty of identification, dominant type of slope movement, primary direction of movement, estimated thickness of material involved in landsliding, and date(s) of known activity. This information is developed from interpreting aerial photographs and examining landslide features in the field. Although preparing detailed landslide-inventory maps involves considerably more time and effort than landslide reconnaissance mapping, these maps are directly useable by planners and decisionmakers as a basis for requiring site-specific investigations prior to development or adopting land-use regulations. Refs.