Overview

The gravity method of geophysical exploration is based on the measurement of variations in the gravity field caused by horizontal variations of density within the subsurface. It is an important technique for many problems that involve subsurface mapping, and it is the principal method in a number of specific types of geological studies. The method, which has its roots in geodetic studies from the seventeenth to the twentieth centuries, has developed rapidly over the past century as a result of significant technological advances: primarily high-accuracy gravity measuring instruments for use on land, sea, and air, and in space, as well as the increasing computational and graphics power of digital computers. These advances are backed up by continuing improvements in data processing, interpretational schemes, practical experience, and surveying methodologies.

Traditionally the gravity method has been used primarily in regional characterization of the Earth for determining the architecture of the crust, identifying potentially favorable regions for resource exploration, and developing conceptual exploration models. This is made possible by the millions of gravity observations now available worldwide in both public and commercial data sets. The accuracy now available in gravity observations and the relative ease of measurement have made the method viable for exploration objectives such as assessing subsurface changes over time and combined interpretation with seismic reflection mapping.