Landslide Mapping with Airborne Laser Swath Mapping (ALSM): Accuracy Assessment

Landslides can cause extensive damage to infrastructure systems including transportation corridors, housing developments, and reservoir systems. Landslides in soil and rock manifest themselves as a surface expression in the earth. An often first step in the delineation and characterization of a landslide is the mapping of the surface of the landslide coupled with the determination of the location of the slip surface. Recent advances in laser scanning technologies provide the ability to delineate surface expressions in intricate detail. Airborne laser swath mapping (ALSM) was used to survey a landslide area along the Missouri River in South Dakota in August 2000. This paper presents the results of a study to assess accuracy of ALSM for application to geotechnical engineering, in particular landslide features. Vertical accuracy of approximately 5 to 20 mm was achieved on the surface of a landslide on the Powerhouse slope near Oahe Dam.