GEODETIC DETERMINATION OF THE KINEMATICS OF CENTRAL GREECE WITH RESPECT TO EUROPE - IMPLICATIONS FOR EASTERN MEDITERRANEAN TECTONICS

We use a new satellite laser ranging/Global Positioning System (SLR/GPS) solution at seven sites in Anatolia and Aegea to obtain a better definition of the extrusion motion of the Anatolian-Aegean block with respect to Europe. We show that this motion can be described in a first approximation by a counterclockwise rotation which transfers most of the motion of Arabia to Anatolia. We combine 78 displacement vectors obtained at common points of two triangulation nets measured in central Greece in 1895 and 1975 with the SLR/GPS measurements to compute the velocity field over Greece with respect to Europe. These measurements indicate that central Greece is a zone of extension between the Anatolian-Aegean counterclockwise rotation to the south and the northern Greece clockwise rotation to the north. This extension is principally localized within the Gulf of Corinth to the east but is distributed to the west. We then extrapolate this velocity field to the whole Aegea and western Anatolia using recently published GPS results as well as the SLR results. The narrow dextral North Anatolian fault, which limits the velocity field to the north, progressively gives way to a much wider boundary zone where extension becomes dominant. We show that the collision between the Mediterranean Ridge and Africa began 3-6 Ma, and we describe the modifications that this collision has produced on the kinematic pattern both in Aegea and on the Mediterranean Ridge.