GeoSure Insurance Product V7 2016.1

This dataset is the Derived Postcode Database issued as part of the GeoSure Insurance V7 incorporating postcode data from OS Code-Point Open version 2016.1. The GeoSure Insurance Product (including the Derived Postcode Database) 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 the Isle of Man), as represented by various layers, starting with Bedrock and moving up to overlying Superficial layers. In 2003, the BGS also published a series of GIS digital maps identifying areas of potential natural ground movement hazard in Great Britain, called GeoSure. There are six separate hazards considered - 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 Great Britain property insurance industry, released as the new GeoSure Insurance Product. This represents the combined effects of the 6 GeoSure hazards on (low-rise) buildings in a postcode database - the Derived Postcode Database, which can be accompanied by GIS maps showing the most significant hazard areas. The combined hazard is represented numerically in the Derived Postcode Database as the Total Hazard Score, with a breakdown into the component hazards. The GeoSure Derived Postcode Database (DPD) is a stand-alone database, which can be provided separately to the full GeoSure Insurance Product V7. The methodology behind the DPD 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. The comparison is done by a process involving expert analysis and statistical interpretations to estimate the potential damage to a property (specifically low-rise buildings only). Each level of each of the hazards is given a 'hazard score' which can then be added together to derive a Total Hazard Score at a particular location (e.g. within a given postcode).