Gravity derived by observing orbital variations of satellites as they are perturbed by the Earth's gravity field provides valuable information about the deep internal structure of the Earth. The coverage is global, encompassing both land and oceans. These data are used in studies of plate tectonics, subduction zones, coremantle and mantle-crust anomalies, and isostatic compensation beneath mountain ranges.
Gravity derived from satellite altimetry measurements and analysis of satellite orbits is an inexpensive way to obtain good spatial coverage over large areas of ocean. It has been used to map fracture zones, seamounts, hot-spot chains, midoceanic ridges, subduction zones, and many previously undiscovered features. In offshore areas where reliable bathymetry is available, the effects of sea-bottom topography can be removed to produce gravity maps suitable for mapping continental-margin structure and detecting sedimentary basins. The long-wavelength components of satellite gravity maps can be used to tie and level smaller marine gravity surveys, providing a common mesh in which local high-resolution surveys are imbedded. In frontier areas, satellite gravity can be processed with bathymetry data to detect submarine basins.