Method for detection of gravitational anomalies

A method of producing a gravitational survey of a region comprising the steps of:

• a) recording a plurality of gravitational measurements from a region in known locations;
• b) obtaining information on the locations of any surface relief in the region likely to have an influence on the gravitational measurements, and estimating the density thereof;
• c) using any information from step (b) to adjust the gravitational measurements to remove the effects thereon caused by the surface relief;
• d) estimating a topological distribution of underground mass in the region;
• characterised in that it includes the additional steps of
• e) measuring a three dimensional (3D) representation of additional elements of the region likely to influence the gravitational measurements, and processing the 3D representation to estimate position and shape characteristics of the additional elements;
• f) estimating a mass or masses of the additional elements of the region from the 3D representation;
• g) providing estimated mass(es) calculated in step (f) along with their position and shape information from step (e), to initialise the estimation procedure of step (d).