Bouguer gravity anomaly

A gravity anomaly after removing an approximate topographic mass contribution, often an infinite slab $2\pi G\rho h$, in addition to free-air reduction. Terrain and spherical-curvature corrections refine the slab model.

An ideal laterally infinite horizontal slab, whose vertical gravity anomaly is proportional to its thickness $h$ and geophysical density contrast $\Delta \rho$ with replaced material. A negative geophysical density contrast gives a negative anomaly in a downward-positive convention. The slab's field above it does not specify burial depth; applying it to finite bodies is an approximation.

A correction for the difference between real surrounding relief and the assumed simple topographic slab. Its computation needs terrain geometry and an assumed density, and can matter in rough surface topography.