The past and future geography of the Eastern Mediterranean constructed from GNSS observations

Abstract

The seismic activity of the Alpine-Himalayan belt is distributed over a wider region than is that of most oceanic active belts, and its deformation cannot be described by the relative rotation of a small number of large rigid plates. One of the most active regions of this belt is the Eastern Mediterranean, which has been intensively studied using earthquake seismology and satellite geodesy. At present there is no agreement as to whether the observed kinematics should be described using a large number of microplates or by continuous deformation. The two approaches are combined here, by dividing the region into four large deformable patches whose relative velocity consists of two parts: a rigid rotation about a pole and a continuous distributed deformation. This description of the kinematics allows reconstruction of the past geography of the region and its elevation to be made relative to Eurasia taken to be fixed. The resulting displacements agree reasonably well with independent estimates of the displacements on the North and East Anatolian Faults, the length of the subducted slabs beneath the Aegean and Western Turkey, and paleomagnetic measurements of rotation. The principal force driving the deformation is the release of gravitational energy by the subduction of old oceanic lithosphere and rollback of the Hellenic Arc, not continental spreading. Projection of the displacements 8 Ma into the future shows how the Eastern Mediterranean will evolve to resemble the Western Mediterranean.