Continental collision with finite indenter strength: 2. European Eastern Alps

Abstract

Comparison of the results of a thin viscous sheet model with the velocity field determined by GPS stations in the Alpine‐Pannonian realm shows that the Adriatic plate is only slightly stronger than the Eastern Alps. The observed velocity field is best approximated with a Newtonian fluid. However, this scenario must be fairly recent, as the overall geometry of the orogen can only be reproduced if the rheology contrast was about 1:10 before the late Miocene. The boundary conditions for this model are tested against the orientation of the intraplate stress field and are robust for Argand numbers between 1 and 5. We conclude that the convergence rate between the Adriatic and European plates must have slowed since the Miocene and that the present‐day eastward extrusion of the Eastern Alps is largely due to lateral escape and only to a minor degree due to gravitational collapse. Scaled viscosities of the Eastern Alps are on the order of 1023 Pa s.