Inventory of Holocene Landslides, Peace River Area, Alberta (NTS 84C)

The Peace River Lowlands of Alberta and British Columbia are one of the most historically active mass movement areas in western Canada. At the town of Peace River, Alberta, the Peace River has incised through approximately 120 m of Quaternary sediments and 30 m into the underlying bedrock. Failures of varying types have occurred in both the Quaternary sediments and the underlying shale bedrock during incision and valley widening processes. Numerous failures continue to cause infrastructure problems for the town of Peace River and impacts roads and rail lines in the area. Valleys containing tributaries of the Peace River, such as the Smoky River, Heart River, Whitemud Creek, Cadotte River and Buchanan Creek valleys have also been actively failing during the Holocene.

The Alberta Geological Survey has recently completed a large surficial mapping program in the Peace River map-area (NTS 84C). Relevant information such as colluvium polygons, landslide symbols and sediments of known higher activity levels (i.e., glaciolacustrine sediments) were filtered in a geographical information system (GIS) to produce a landslide inventory map. The landslides represented by point and line symbols were then examined using air photograph stereo pairs and crudely classified and subsequently tagged in the GIS. This process created a derivative digital product from existing surficial maps with active digital layers of various surficial materials, landslide types and areas affected by existing landslides. A total of 157 landslide features are contained in the inventory and were classified according to material type, movement type and mode of movement. The scale of the air photos used allowed the identification of landslides with minimum length and width dimensions of 240 m.

This regional inventory provides an overview of landslide data for the Peace River map area that may be incorporated into future landslide hazard investigations in the area, and provides a framework for the development of similar inventories from other maps created through the surficial mapping initiative.