Topographic masses and mass heterogeneities in the upper mantle

Ctirad Matyska

Summary

The modified geoid which had been evaluated by incorporating the gravitational effect both of the Earth's surface undulations and the crustal thickening exhibits a high correlation with surface tectonics. It was interpreted by means of mass heterogeneities in the upper mantle. To get the uniqueness of this inversion, Tanimoto's tomographic density anomalies were employed as the a priori reference model. Results were compared with the case when only a spherically symmetric reference model was available. Good correlation between the mass heterogeneities and the surface tectonics as well as relatively low amplitudes were obtained in both cases. This suggests that the part of surface topography, which is not compensated by the crustal thickening, is associated with dynamic processes in the Earth's mantle and could be used to constraint models of dynamic topography resulting from computations of mantle convection.


In: Gravimetry and Space Techniques Applied to Geodynamics and Ocean Dynamics, B. E. Schutz, A. Anderson, C. Froidevaux, and M. Parke (eds.), Geophysical Monograph 82, IUGG Volume 17, IUGG and AGU, pp.125-132, 1994.