Refinement of the normal Eötvös matrix and its influence on the estimation of the deflections of the vertical

The elements of the Eötvös matrix, usually determined by torsion balance measurements, are useful in many geodetic applications. We present a method for the computation of the elements of the normal Eötvös matrix at a point on the Earth’s physical surface, resulting in an improvement in the determination of the deflection of the vertical at intermediate points of a network. In the process, we also present analytical expressions for the computation of the components of the deflection of the vertical. From those expressions and using also a numerical example, we show that the proposed refinement is not completely negligible.

A 3D model of the Wathlingen salt dome in the Northwest German Basin from joint modeling of gravity, gravity gradient, and curvature

In the past few decades, numerous attempts have been made on modeling of salt tectonics and deciphering the geometry of salt domes, which is a key challenge in petroleum exploration. We have derived a 3D density model of the Wathlingen salt dome, situated in the southern part of the Northwest German Basin from joint modeling of reprocessed torsion balance measurements. Gravity, gravity gradients [Formula: see text], curvature derived from horizontal gravity gradients [Formula: see text], and horizontal directive tendency are jointly modeled to decipher the geometric structure of the salt dome. The model was constrained by geologic and borehole information. We found that the Wathlingen salt dome is a mushroom-structured salt body, which is 14-km long, 4–8-km wide extending up to [Formula: see text] depth. The top mushroom structure of the salt is horizontally spread up to [Formula: see text]. It would not have been possible to derive the complex 3D structure from modeling of gravity data alone.