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- Title
Probabilistic Linear Inversion of Satellite Gravity Gradient Data Applied to the Northeast Atlantic.
- Authors
Minakov, Alexander; Gaina, Carmen
- Abstract
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. Plain Language Summary: In our study, we use data obtained by the GOCE satellite mission which measured with high precision how strongly the Earth's gravity changes in three dimensions. We develop a numerical method to link these data to local density changes inside the deep Earth. Using this method, we identify low‐density regions (rocks that are lighter by about 30 kg m−3 compared to the average) at the depth of 100–150 km beneath the North Atlantic Ocean. The location of the anomalous density regions coincides with the areas of volcanic activity such as Iceland, Jan Mayen, and other groups of smaller underwater volcanoes. Key Points: We present a methodology for 3‐D linear inversion of satellite gravity gradient data using statistical prior informationWe apply the inversion method to estimate the density variation in the upper mantle beneath the northeast Atlantic OceanThe predicted density variations are compared to independent results of seismic tomography and linked to distribution of Cenozoic submarine volcanoes and seamount‐like features of the seafloor
- Subjects
ATLANTIC Ocean Region; SATELLITE-based remote sensing; PROBABILISTIC databases; GRAVIMETRY; EARTH'S mantle; GAUSSIAN distribution; SEISMIC tomography
- Publication
Journal of Geophysical Research. Solid Earth, 2021, Vol 126, Issue 12, p1
- ISSN
2169-9313
- Publication type
Article
- DOI
10.1029/2021JB021854