Use of GOCE Satellite Gradient Gravity Data for Forward and Inverse Modeling of the NE Atlantic Margin

Abstract

We present a case study for the North-East Atlantic margin, where we analyze the use of satellite gravity gradients by comparison with a well-constrained 3D model. The model is based on a wealth of seismic profiles, commercial and scientific borehole data from the shelf and mainland Norway, petrophysical sampling and a dense coverage of gravity and aeromagnetic data. The 3D model provides a detailed picture from the upper mantle to the top basement (base of sediments). We analyze how gravity gradients can increase confidence in the modeled structures. Initial results indicate for example that a lateral variable surface density, which reflects geology, has a small influence on the gravity gradients at satellite height. However, the gravity gradients are sensitive to the crustal geometry and upper mantle density structure, which make them an ideal addition to forward and inverse modeling of the lithosphere. The next step will be to calculate a sensitivity matrix for the entire 3D model. This sensitivity matrix describes the relation between calculated gravity gradient data and geological structures with respect to their depth, extent and relative density contrast, and will be used for joint inversion of gravity and gravity gradients.