Probabilistic Linear Inversion of Satellite Gravity Gradient Data Applied to the Northeast Atlantic

• Published in: Journal of Geophysical Research: Solid Earth
• Main Authors: Minakov, Alexander, Gaina, Carmen
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley-Blackwell 2021
• Subjects: geostatistics; gravity; inverse problem; lithosphere; mantle; modeling; Greenland; Iceland; Northeast Atlantic
• Online Access: https://eprints.qut.edu.au/231399/

We explore the mantle density structure of the northeast Atlantic region using constrained linear inversion of the satellite gravity gradient data based on statistical prior information and assuming a Gaussian model. The uncertainty of the residual gravity gradient signal is characterized by a covariance matrix obtained using geostatistical analysis of controlled-source seismic data. The forward modeling of the gravity gradients in the 3D reference crustal model is performed using a global spherical harmonics analysis. We estimate the model covariance function in the radial and angular directions using a variogram method. We compute volumetric gravity gradient kernels for a spherical shell covering the northeast Atlantic region down to the mantle transition zone (410 km depth). The solution of the linear inverse problem in the form of the mean density model and the posterior covariance matrix follows a least squares approach. The results indicate that on average the seismic velocity variation is proportional to the density variation in the northeast Atlantic region. However, a noticeable mismatch or anti-correlation exists in some areas, such as the Greenland-Iceland-Faroe ridge and southwestern Norway. The predicted low-density anomalies at depths of 100–150 km underneath the northeast Atlantic Ocean are correlated with the distribution of Cenozoic submarine volcanoes and seamount-like features of the seafloor.