Tectonic versus glacial isostatic adjustment deformation in Europe

Tectonic deformation induced by the Alpine collision and Glacial Isostatic Adjustment (GIA) in Europe are modelled by means of a finite element scheme and viscoelastic normal modes techniques in order to compare the resulting deformation patterns with the ITRF2000 (International Terrestrial Reference Frame) geodetic dataset. Due to the Alpine collision and to the flow from the equatorial mantle to the deglaciated regions in the northern hemisphere, both tectonics and GIA contribute to the observed widespread shortening, with tectonics playing a major role in the southern part of the modelled domain, from Potsdam to the Alpine front, and GIA affecting the shortening in proximity of the region subject to post glacial rebound. Since the stiff Baltic Shield causes a counterclockwise rotation of the collision velocity away from the shield itself and the GIA induced velocities are directed outward from the deglaciated region, both tectonics and GIA contribute to the observed east-west baseline extension of 0.8-1.1 mm/yr at the latitude of ONSA.