Catherine Pennington

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.

Landslide management in the UK—the problem of managing hazards in a ‘low-risk’ environment

The UK is a country with limited direct experience of natural disasters. Whilst landslide losses are not negligible and fatalities are rare, accounts are under-reported. Financial losses from landslides are poorly understood but likely to be considerably in excess of £10 million per year. As a result, a strategic management framework has evolved based upon small, low-impact events punctuated by occasional larger events or larger landslides affecting urban areas. We present an overview of the different landslide management mechanisms in the UK and discuss them in context of cases studies to explore their effectiveness. We conclude with three issues that may have implications for landslide management in the UK and other ‘low-risk’ countries. Firstly, the evidence base by which landslide hazards and risks are measured is insufficient and limitations in existing information need to be better understood. Secondly, existing guidance on strategic and responsive management needs to be assessed for its fitness for purpose. Thirdly, we encourage debate about the importance of near misses.

Monitoring coastal change using terrestrial LiDAR

Abstract The paper describes recent applications by the British Geological Survey (BGS) of the technique of mobile terrestrial Light Detection And Ranging (LiDAR) surveying to monitor various geomorphological changes on English coasts and estuaries. These include cliff recession, landslides and flood defences, and are usually sited at remote locations undergoing dynamic processes with no fixed reference points. Advantages, disadvantages and some practical problems are discussed. The role of GPS in laser scanning is described.

Antecedent Precipitation as a Potential Proxy for Landslide Incidence in South West United Kingdom

This paper considers the effects of antecedent precipitation on landslide incidence in the United Kingdom. During 2012–2013 an extraordinary amount of precipitation resulted in an increase in the number of landslides reported in the UK, highlighting the importance of hydrogeological triggering. Slope failures (landslides on engineered slopes) in particular caused widespread disruption to transport services and damage to property. SW England and S Wales were most affected. Easy-to-use and accessible indicators of potential landslide activity are required for planning, preparedness and response and therefore analyses have been carried out to determine whether antecedent effective precipitation can be used as a proxy for landslide incidence. It is shown that for all landslides long-term antecedent precipitation provides an important preparatory factor and that relatively small landslides, such as slope failures, occur within a short period of time following subsequent heavy precipitation. Deep-seated, rotational landslides have a longer response time, as their pathway to instability follows a much more complex hydrogeological response. Statistical analyses of the British Geological Survey landslide database and of weather records have enabled determination of the probability of at least one landslide occurring based on antecedent precipitation signals for SW England and S Wales. This ongoing research is of part of a suite of analyses to provide tools to identify the likelihood of regional landslide occurrence in the United Kingdom.

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.

Geophysical-Geotechnical Sensor Networks for Landslide Monitoring

In this study we describe the development of an integrated geophysical/geotechnical sensor network for monitoring an active inland landslide near Malton, North Yorkshire, UK. The network is based around an automated time-lapse electrical resistivity tomography (ALERT) monitoring system, which has been expanded to incorporate geotechnical sensor arrays. The system can be interrogated remotely using wireless telemetry to enable the near-real-time measurement of geoelectric, geotechnical and hydrologic properties.

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

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.