Page "Gravimetry" Paragraph 5

Besides precision, stability is also an important property of a gravimeter, as it allows the monitoring of gravity changes.

These changes can be the result of mass displacements inside the Earth, or of vertical movements of the Earth's crust on which measurements are being made: remember that gravity decreases 0. 3 mGal for every metre of height.

The study of gravity changes belongs to geodynamics.