Landslide susceptibility in sensitive clay in eastern Canada: some practical considerations and results in development of an improved model

Abstract

This article describes the development of an improved and expanded landslide susceptibility model for eastern Ontario and southern Quebec, where the clay plains of the former Champlain Sea are affected by large landslides in sensitive clay. The work uses the weights of evidence method and considers 12 different geospatial themes, of which seven are included in the final model: soil type, overburden thickness, flow accumulation, elevation, stream sinuosity, local relief, and slope angle. The article describes some practical considerations in the current modelling work, with emphasis on a number of key aspects, including identification of target hazard types, selection of analytical and predictive study areas, selection of geospatial thematic data for analysis, image processing and analysis of both discrete- and continuous-valued raster data, and combination of thematic weights for development of a meaningful susceptibility model. The new model has significantly better predictive power than the older model and covers the entire area. It does not fully address earthquake-related landslide hazards and would benefit from expansion of the digital landslide inventory.