Global to local Moho estimate based on GOCE geopotential models and local gravity data

Collocation approach has been applied to get a global Moho model in spherical approximation based on a GOCE geopotential model. A simple single layer model, with known density contrast, has been considered and a linearized relationship between the spherical harmonic coefficients of the anomalous potential and those of the Moho depth has been derived. This allows the covariance propagation from gravity to Moho depth. The derived covariance functions are then used in the collocation estimate of the global Moho depth. In order to be as close as possible to the considered model, reductions for the gravity signal related to topography/bathymetry have been applied. Simulated and real data tests have been performed and the obtained global solution has been compared with Moho estimates available in literature. The obtained global Moho has been then used as a starting solution for a regional refinement assuming planar approximation. In this second step the computation has been performed in the Central Mediterranean area, based on collocation, local gravity and topography/bathymetry data.