Downie Slide: An integrated remote sensing approach to characterization of a very slow moving landslide

This study demonstrates the advantages of combining remote sensing with field data in landslide investigations and provides improved data on the structural geology and its influence on slope movements at Downie Slide, a large landslide located in southeastern British Columbia, Canada. The geomorphology of the Downie Slide was studied using airborne LiDAR in a GIS environment to provide new insights on the landslide displacement mechanism. Surface and underground areas of the slide were compared and contrasted using terrestrial laser scanning and photogrammetry. Six joint sets were identified. Some structures and domain boundaries were found to be pervasive throughout the slide. A correlation between slope deformation, and large-scale structural and damage features was made and 12 structural domains defined within the landslide. Large secondary retrogressive-failures were identified for the head scarp and retrogression of the northern boundary, increasing the overall area of slide material by ~ 1 km2.