Creation of a National Landslide Domain Map to Aid Susceptibility Mapping in Great Britain

Abstract

The need to develop a national map that characterises landslides across Great Britain has long been recognised by the British Geological Survey as part of its strategic role providing hazard information to stakeholders. Hierarchical landslide domains represent areas of similar physiographic, meteorological, climatic and geological characteristics that shaped the style of landsliding. Developed to underpin current research into how different types of landslides and terrains will be affected by changing environmental conditions, the map further assists development of a national landslide susceptibility map with conditioning factors tailored to a specific domain. This paper considers the role of national-scale land systems mapping to create a Landslide Domain Map, the refinement of a national model using landslide inventories to better reflect the spatial extent and characteristics of landslides within domains. The distribution of landsliding in Great Britain is a product of the complex range of lithologies and geomorphological processes active under a range of climatic conditions. The domains represent landslides across a series of unstable slopes ranging from very large, ancient landslides formed under periglacial climate conditions to small, modern failures, particularly along transport infrastructure corridors. Although analysis of the National Landslide Database broadly informed the nature of landsliding within a specific domain, expert knowledge was needed to supplement it especially in areas where recent mapping had not taken place. Targeted data collection is planned in data-poor domains to supplement the database. Further domain-specific research is ongoing and includes development of semi-empirical process-specific models involving the weighting of critical factors in order to refine the current national landslide susceptibility map, GeoSure. As an example of this refinement, this paper discusses an improved debris flow model for the Scottish Highlands.