Abstrct: Convection Currents in the Earth's Mantle and the Spherical Harmonic Development of the Topography of the Earth

Abstract

Convection Currents in the Earth's Mantle and the Spherical Harmonic Development of the Topography of the Earth

A system of simple principles concerning the kinematics of the convection currents in
the Earth's mantle was postulated as the starting point. The mantle is supposed to become more and
more homogeneous downward. Here it is essential, for the reason of symmetry, that the current
system has a degree of regularity as high as possible and is modified only in the upper part, mainly
due to the distribution of continents and oceans. The adequate system is chosen by the help of the
theory of point groups. Evaluating the distribution to be expected of the coefficients of the spherical
harmonic development of the Earth's theoretical topography by means of electronic computers,
accordance is found for the extrema to the 31st order, i.e. as far as they have been determined until
now. - The system yields the seismic discontinuities of the Earth's mantle as a secondary product.
That does not mean that the system explains them, but it is absolutely consistent with them. That
seems to be a quantitative proof of the system regarded as probable on the strength of group-theoretic
considerations.