CGRG Bibliography of Canadian Geomorphology
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Author : Geertsema, M.; and Schwab, J.W.
Date : 2006.
Title : Challenges with terrain stability mapping in northern British Columbia.
Publication : Streamline. Watershed Management Bulletin
Issue : 10(1):
Page(s) : 18-26.
Abstract
In British Columbia, the basis for most landslide hazard mapping is the terrain stability map (TSM), which combines surficial geology with modifying geomorphic processes. A system of TSM has been developed for the forest sector to identify a polygon-based classification of the likelihood of landslide occurrence following timber harvesting and (or) road building. The purpose of this paper is to introduce geological conditions common in northern BC that require special considerations in terrain stability mapping and assessments, where standard forestry-related TSM may not be sufficient or is not the appropriate tool for assessing the over all slope stability hazard. More importantly, below-ground (not visible) and off-site conditions should be considered for assessing hazards for large and (or) complex land slides. Slope hazards generally not considered in forestry application are discussed in this article. Topics include situations where rock slides trigger larger movements in soil, glaciomarine sediments, permafrost areas, and preglacial buried valleys. Accurate assessment of terrain stability hazard can be challenging in certain landscapes of northern BC. This is especially true of landscapes: where upslope rock slides trigger larger landslides in soil—phenomena not possible without the undrained loading mechanism; and where key elements that affect landslide kinematics are not discernible (or readily discernible) from surface morphology. Key elements include sensitive or quick zones in glaciomarine sediments, permafrost, and subsurface bed rock topography. In the latter case, terrain is particularly prone to large catastrophic landslides where preglacial valleys are infilled with clayey tills or with till-covered glaciolacustrine sediments.
Bibliography of Canadian Geomorphology