The GeoSure Insurance Product (GIP) dataset identifies potential natural ground movement hazard within Great Britain by postcode. These data are available in GIS point feature and database format, updated on a 6 monthly basis. The GeoSure Insurance Product represents the end of an interpretation process starting with the BGS Digital Geological Map of Great Britain at the 1:50,000 scale (DiGMapGB-50). This digital map is the definitive record of the types of rocks underlying Great Britain (excluding Northern Ireland), as represented by various layers, starting with Bedrock and moving up to overlying Superficial layers. In 2003, the BGS published a series of GIS digital maps identifying areas of potential natural ground movement hazard in Great Britain, called GeoSure, demonstrating a grade of potential for 6 separate hazards: shrink-swell clays, slope instability, dissolution of soluble ground, running sand, compressible and collapsible deposits. These maps were derived by combining the rock-type information from DiGMapGB-50 with a series of other influencing factors which may cause the geological hazards (e.g. steep slopes, groundwater). In 2005, the BGS used the GeoSure maps to make an interpretation of subsidence insurance risk for the British property insurance industry, released as the GeoSure Insurance Product. This represents the combined effects of the 6 GeoSure hazards on buildings in a postcode database. The combined hazard is represented numerically in the database as the Total Hazard Score, with a breakdown into the component hazards. The methodology behind these data involves balancing the 6 GeoSure natural ground stability hazards against each other. The GeoSure maps themselves have a fivefold coding (A to E), and the balancing exercise involves comparing each level across the six hazards e.g. comparing a level C shrink-swell clay area with a level C running sand area. Each level of each of the hazards is given a 'hazard score' which can then be added together to derive a Total Hazard Score within a 300m radius from the population weighted postcode point.
