Lower mantle heterogeneity, dynamic topography and the geoid

Density contrasts in the lower mantle, inferred using seismic tomography, drive viscous flow; this results in kilometres of dynamically maintained topography at the core–mantle boundary and at the Earth's surface. The total gravity field due to interior density contrasts and dynamic boundary topography predicts the longest-wavelength components of the geoid remarkably well. Neglecting dynamic surface deformation leads to geoid anomalies of opposite sign to those observed.

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