ABSTRACT: Recent landslides on frozen rupture surfaces in British Columbia.

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

Recent debris flows occurred in Mount Robson Provincial Park and on Pink Mountain, in east-central and northeastern British Columbia, respectively. While both landslides involved frozen rupture surfaces, one occurred in seasonally frozen ground, whereas the other occurred along the upper boundary of permafrost. In both cases, the frozen horizons likely acted as barriers to water movement, with preferential flow occurring along their upper boundaries. The Mount Robson Park landslide occurred in early November 2007, on a steep, 35°, south-facing slope. Field evidence supports movement of a thin layer of thawed soil over seasonally frozen ground. The debris flow travelled 750 m down a steep slope and another 600 m on a fan. Distal debris flood sediments were deposited across two buried pipelines and came to rest in the ditch against the Yellow Head - Trans Canada Highway. No damage was done to infrastructure. Sometime around September 2008 a steep, 32°, matrix-supported talus slope failed, resulting in a landslide. The rupture surface, 3 m below the pre-slide ground surface, contained ice-rich permafrost. After 90 m of sliding, the moving mass transformed into a slow-moving debris flow. The total travel distance of the landslide was 260 m. The studied events give the opportunity of analyzing the role of frozen ground in conditioning slopes for mass movements, as well as examining landslide triggers under a warming climate.

Bibliography of Canadian Geomorphology