UPPER MANTLE STRUCTURE IN THE ALPINE ZONE FROM SURFACE WAVE TOMOGRAPHY

Abstract

The present-day Alpine region began to form more than 100 Ma ago with the subduction of a Tethyan branch beneath the Adriatic plate, eventually arriving at the collisional stage of the European continental lithosphere at about 40 Ma ago. Presently, Africa is moving northward relative to Europe at a rate of about 0.5 cm/yr, but most of the shortening is absorbed in the Southern Tyrrhenian Sea. The eastern Alps overlap with the Dinarides subduction, where the Adriatic plate is rather subducting underneath Eurasia. For a better understanding of the geodynamic processes in the Alpine–Dinaric region, a reliable knowledge of the lithosphere–asthenosphere system structure is needed. However, existing information on the upper mantle structure obtained from body and surface wave tomography data is fragmentary and sometimes contradictory.