Deviation of the Earth’s crust and upper mantle from isostatic equilibrium

The isostatically unbalanced crust and upper mantle structures conforming to the external gravitational field and minimizing deviation of the internal gravitational field from the isostatic equilibrium field, are determined. A dipole-type distribution of these structures associated with the motion of anomalous masses toward the potential energy minimum is revealed. On the basis of seismic data, it is inferred that the compensation of isostatically unbalanced masses is possible at the core-mantle boundary.