High-Resolution Measurements of Non-Linear Spatial Distribution of Gravity Gradients in Hungary

Linear changing of the gravity gradients between the adjoining network points is an important demand for different interpolation methods in geodesy (e.g. interpolation of the deflection of the vertical, geoid computations, and interpolation of the gravity values or the vertical gradients of gravity). To study the linearity of gravity gradients, torsion balance measurements were made both at the field and in a laboratory: one is at the southern part of the Csepel island, and the other in the Geodynamical Laboratory of Loránd Eötvös Geophysical Institute in the Mátyás cave. The results of our investigations show that the linearity of the gravity gradients mainly depends on the given point density and the the geological fine structure of rocks and shallow subsurface density. It seems the given point density of the earlier torsion balance stations may be not enough for some geodetic purposes, moreover the problem could not be solved even applying topographic reduction of gravity gradients.