Paper No. 6
Presentation Time: 9:30 AM


BLAIS-STEVENS, Andree1, KREMER, Marian2, BONNAVENTURE, Philip3, SMITH, Sharon2, LIPOVSKY, Panya4 and LEWKOWICZ, Antoni G.5, (1)Geological Survey of Canada, Ottawa, ON K1A 0E8, Canada, (2)Geological Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8, Canada, (3)Geography, Queen's University, Mackintosh-Cory Hall, Kinsgton, ON K7L3N6, Canada, (4)Yukon Geological Survey, 300 Main Street, Whitehorse, YT Y1A2B5, Canada, (5)Geography, University of Ottawa, 60 University Private, Ottawa, ON K1N 6N5, Canada,

The Alaska Highway Corridor in southern Yukon traverses the discontinuous permafrost zone from the Alaska border to British Columbia. The highway is a vital transportation route with 85% of the local population living along it and a pipeline has also been proposed for the corridor.

Air-photos and high-resolution satellite imagery were utilized to update the landslide inventory and landslide susceptibility modelling was conducted to provide baseline geoscience information for decision-makers. A total of about 1400 landslides out of 1950 ground hazard features were identified, representing about 1 landslide per 15 km2. Prominent landslide types included debris slides (38%), debris flow deposits (37%), rock slides (13%), earth slides/flows (6%), rock falls (4%), combined active layer detachment slides (ALD) and retrogressive thaw slumps (RTS) (3%). Other ground hazards identified were thermo-karstic depressions, rock glaciers, and solifluction.

A qualitative heuristic method was used to develop landslide susceptibility models based on triggering factors and included Rockfall/rock slides, Debris flows, ALD and RTS. Weighted data layers combined in the model include slope, aspect, vegetation, surficial or bedrock geology unit, potential incoming solar radiation, distance to drainage or fault and a permafrost probability distribution model. Equilibrium permafrost distribution projected for air temperature increases of 1°C, 2°C, and 5°C, was also incorporated into RTF and ALD susceptibility models to assess the potential impact of climate change on landslide susceptibility. Results indicate that with reduced permafrost extent, there will be fewer zones of high susceptibility. Although landslide susceptibility maps for warmer conditions give a "snapsnot" of a potential decrease in zones of high susceptibility, the slope processes that will likely take place as permafrost warms and thaws have not been considered. As warming occurs, there will likely be more ALD and RTS activity until conditions stabilize following permafrost degradation.