THE QUESTION OF SECULAR VARIATIONS IN THE EARTH'S GRAVITY FIELD FROM MASSDISPLACEMENTS IN THE EARTH'S DEEP INTERIOR

There is no doubt that gravity changes due to mass displacement close to the earth's surface. There can be variations from fluctuations of the groundwater table, tectonic movements connected with landuplift or magna flow. The question, if there are variations due to mass displacements, is very much the question, where we have the origin of the lower harmonics in the earth's gravity field. If their sources are zonal density anomalies in the fluid core, secular variations can be expected. The lower harmonics do not show any correlation to the distribution of continents and oceans. Consequently an anomalous density distribution must exist in parts of the earth's interior which are deeper than the earth's crust. The report discusses mass distributions to explain lower harmonics in the earth's gravity field. (Author) See also AD-702 486.