C. Foster

The national landslide database of Great Britain: development, evolution and applications

Landslide inventories are essential because they provide the basis for predictive landslide hazard and susceptibility assessments and because they allow for the manipulation and storage of temporal and spatial data. The National Landslide Database has been developed by the British Geological Survey (BGS). It is the most extensive source of information on landslides in Great Britain with over 15,000 records of landslide events each documented as fully as possible. This information is invaluable for planners and developers as it helps them investigate, avoid or mitigate areas of unstable ground in accordance with Government planning policy guidelines. Therefore, it is vital that the continual verification, collection and updating of landslide information is carried out as part of the Survey’s ‘National Capability’ work. This paper describes the evolution from a static database to one that is continually updated forming part of a suite of national digital hazard products. The history of the National Landslide Database and associated Geographical Information System (GIS) is discussed, together with its application and future development.

New Developments in Harmonized Landslide Susceptibility Mapping over Europe in the Framework of the European Soil Thematic Strategy

In the context of the European Soil Thematic Strategy, and the formulation of a draft of a European framework directive devoted to the sustainable use of soil, landslides are recognized as one of the eight soil threats requiring harmonized spatial hazard assessments over the EU territory. The general framework for such assessments consists of a nested geographical approach based on “Tiers”, where a low-resolution (1:1 Million) evaluation (“Tier 1”) using already available pan-European datasets should enable the delineation of priority areas requiring more detailed assessments with additional data (“Tier 2”). In this contribution, we present new developments in the elaboration of a “Tier 1” generic landslide susceptibility evaluation based on a heuristic modelling approach exploiting the most important landslide conditioning factors. Extensive landslide locations available at small spatial scales have been collected and harmonized over the EU territory to be used for input parameter specification and model calibration, evaluation and classification. Since the analyzed area is highly complex in terms of climato-physiographic conditions controlling landslide occurrences, a preliminary landslide terrain differentiation is proposed consisting of eight calibration zones where specific predictor class weights have been allocated through a heuristic indexing approach. The spatially combined preliminary pan-European susceptibility estimate classifies 13 % of the EU territory as prone to landslides, thus requiring more detailed, quantitative inventory-based susceptibility evaluations (“Tier 2”).

Mapping a Nation’s Landslides: A Novel Multi-Stage Methodology

Through combining new technologies and traditional mapping techniques, the British Geological Survey (BGS) has developed a novel, multi-stage methodology for landslide mapping. 3-D aerial photograph interpretation, variable-perspective 3-D topographic visualisation and field mapping with digital data capture are being used to map the UK’s landslides. The resulting ESRI ArcGIS polygons are published on BGS 1:50,000 geological maps and as digital data products. Data collected during mapping are also uploaded directly into the National Landslides Database maintaining a systematic, nationally-uniform landslide inventory. Repeat monitoring of selected landslides using terrestrial LIDAR and dGPS allows the database to be frequently updated and the proactive Landslide Response Team means that new landslide events can be mapped within days, if not hours, of their occurrence. The long-term aim is to apply this methodology throughout the UK, providing a wealth of data for scientific research and hazard assessment. This methodology is also suitable for application in an international context.