Seafloor topography variations mapped by regional gravity tensor analysis

The AGOSTA project initially proposed by our team and lately funded by CNES TOSCA consists of developing efficient approaches to restore seafloor shape (or bathymetry), as well as lithospheric parameters such as the crust and elastic thicknesses, by combining different types of observations including gravity gradient data. As it is based on the second derivatives of the potential versus the space coordinates, gravity gradiometry provides more information inside the Earth system at short wavelengths. The GOCE mission has measured the gravity gradient components of the static field globally and give the possibility to detect more details on the structure of the lithosphere at spatial resolutions less than 200 km. We propose to analyze these satellite-measured gravity tensor components to map the undersea relief more precisely than using geoid or vertical gravity previously considered for this purpose. Inversion of vertical gravity gradient data derived from the radar altimetry technique also offers the possibility to reach greater resolutions (at least 50 km) than the GOCE mission one. The seafloor topography estimates are tested in areas well-covered by independent data for validation, such as around the Great Meteor guyot [29°57′10.6″N, 28°35′31.3″W] and New England seamount chain [37°24′N 60°00′W, 120° 10' 30.4" W] in the Atlantic Ocean as well as the Acapulco seamount [13° 36' 15.4" N, 120° 10' 30.4" W] in the Central Pacific.