Potential Field Techniques
Microgravity Profiling
Outline
Microgravity profiling is a passive technique that involves highly accurate (to within 1 part in 109 (1mgal)) measurement of relative changes in the Earth's gravitational field. Measurements are made using a microgravity meter, which essentially comprises a highly sensitive temperature stabilised spring balance. Subtle changes in gravity result from variations in the density of materials within the subsurface and the method can therefore be used to successfully locate voids or buried features such as underground storage tanks (USTs). The effects of tidal and instrument drift that would otherwise mask any subtle anomalies are overcome by repeat readings at a fixed base station throughout the survey. Accurate topographic levelling is carried out at each station in order to correct for the effects of terrain.
