Renaissance of Torsion Balance Measurements in Hungary

Abstract

In the 20th century, a large amount of torsion balance measurements have been carried out around the world. The measurements still provide a good opportunity to detect the lateral underground mass inhomogeneities and the geological fault structures using the so called edge eects in gravity gradients. Hitherto almost 60000 torsion balance measurements were made in Hungary mainly for geophysical purposes. Only the horizontal gradients were used for geophysical prospecting, the curvature gradients measured by torsion balance remained unused. However, curvature gradients are very useful data in geodesy, using these gradients precise deflections of the vertical can be calculated by interpolation and using astrogeodetic determination of the geoid the fine structure of the geoid can be derived. In our test area a geoid with few centimeters accuracy was determined based on the curvature data. Based on the horizontal and the curvature gradients of gravity the full Eötvös tensor (including the vertical gradients) can be derived by the 3D inversion method. In our earlier research works additional new torsion balance measurements were necessary. Applying the new technical opportunities we reconstructed and modernized our older instruments, and additional torsion balance measurements have been made to study the linearity of gravity gradients.