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Published September 1978 | public
Journal Article

Equation of state fits to the lower mantle and outer core

Abstract

The lower mantle and outer core are subjected to tests for homogeneity and adiabaticity. An earth model is used which is based on the inversion of body waves and Q-corrected normal-mode data. Homogeneous regions are found at radii between 5125 and 4825 km, 4600 and 3850 km, and 3200 and 2200 km. The lower mantle and outer core are inhomogeneous on the whole and are only homogeneous in the above local regions. Finite-strain and atomistic equations of state are fit to the homogeneous regions. The apparent convergence of the finite-strain relations is examined to judge their applicability to a given region. In some cases the observed pressure derivatives of the elastic moduli are used as additional constraints. The effect of minor deviations from adiabaticity on the extrapolations is also considered. An ensemble of zero-pressure values of the density and seismic velocities are found for these regions. The range of extrapolated values from these several approaches provides a measure of uncertainties involved.

Additional Information

© 1978 Published by Elsevier B.V. Received 22 September 1977, Accepted 11 November 1977, Available online 25 October 2002. Contribution Number 2931, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, U.S.A. This research was supported by NASA contract No. NGL (05-002-069). Rhett Butler was supported by a Fannie and John Hertz Foundation fellowship.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023