A large rockslide-debris avalanche in cohesive soil at Pink Mountain, northeastern British Columbia, Canada

摘要

In early July 2002, a large rockslide-debris avalanche occurred on the west slope of the Pink Mountain anticline in northeastern British Columbia (57 deg 04 min N; 122 deg 52 min W). The slopes have been subjected to previous deformation and landsliding. Pre- and post-slide digital elevation models (DEM-s) were created from aerial photography. Approximately 1.04 M m~3 of sandstone and shale travelled nearly 2 Ian from an elevation of 1460 m to 1010 m. The landslide has a fahrboschung of 11.6 deg and covered 43 ha. The rock debris entrained a certain amount of fine-textured till and colluvium increasing its volume by 15 percent This entrainment caused partial liquefaction of the underlying soil thereby enhancing the mobility of the landslide. We used a Bingham rheological model to dynamically model the landslide with excellent correspondence between the analysis of the actual observed behaviour of the landslide