Gravimetry is a geophysical technique in which the Earth gravitational attraction is observed and interpreted in terms of mass distribution over space/time.
In principle any process that involve anomalies in the density distribution of a body or that can produce mass changes can be studied through Gravimetry; practically the application of gravimetry is actually limited by the capability to model and isolate the different sources of the gravitational field.
First of all, in order to facilitate the interpretation, the gravitational signal is generally filtered and interpolated from the acquisition points to a grid at constant altitude. In this process different data sources (e.g. satellite, airborne and ground) can also be integrated.
Secondly, in order to properly study a specific anomaly, its gravitational signal should be isolated by removing the effect of all the others sources.

Constituents of g

The constituent that make up the force of gravitational acceleration (g) at Earth’s surface (credit ESA–AOES Medialab).

Finally an inversion algorithm can be applied to retrieve information on the studied anomaly.

Gravimetry plays nowadays a key role in numerous Earth science applications such as mapping of crustal thickness, subsurface geology, monitoring of snow and water mass movement, tidal studies and oceanographic studies.

In this framework GReD has studied and developed:
– a set of numerically-optimized tools, based on fast Fourier techniques, to compute the gravitational effect of a given body;
– a semi-automatic software based on a least squares solution to merge gravitational observations coming from different sources and compute grids of gravity anomalies;
– a set of stochastic algorithms to perform the inversion of the gravitational field from global to local scales.

 

topography

Topography

potential_topo

Gravitational potential

first_topo

First radial derivative of the gravitational potential

second_topo

Second radial derivative of the gravitational potential