Gravity and magnetic surveys involve measuring the Earth's gravitational and magnetic fields using highly sensitive instruments. These Potential Field measurements can be made on the Earth surface, both on land and the sea bottom, from ships or from aircraft.
The data from the surveys are processed in a number of ways but usually produce some form of anomaly value, i.e. a variation from what would normally be expected at that point. These gravity and magnetic anomalies can be attributed to variations in the Earth's crust and are a major asset in mineral and hydrocarbon exploration, as well as furthering our understanding of the deeper Earth structure and processes.
The database comprises over 155 000 gravity observations covering the whole of Great Britain.
Most of the surveys were carried out by the BGS but the database includes data originally acquired by other organisations and subsequently given to the BGS to be managed as part of the national archive.
The Bouguer gravity anomaly records for the whole of Great Britain are available for free download.
More about the Land gravity survey data
A regional aeromagnetic survey of Great Britain was carried out as a series of surveys flown between 1955 and 1965.
Flying height mostly 1000 feet (305 m) with 2 km line separation.
Cornwall and Devon, which also includes Radiometric, VLF and EM data flown at 500 feet (with 400 m line separation).
The digital dataset was created by BGS during the 1980s by hand digitising some 540 000 magnetic values from the analogue records.
The aeromagnetic anomaly records for the whole of Great Britain are available for free download.
More about the GB Aeromagnetic Survey data