EXTENSIONAL TECTONICS OF THE CENTRAL GREECE AS A MATTER OF COUPLING AND DECOUPLING OF THE AEGEAN PLATE OVER THE AFRICAN (NUBIAN) PLATE

The fault’s arrays crossing through Greece change in orientation and kinematics from south to north and from east to west, attesting to the geotectonic complexity of Greece. This complexity is related either to the proximity of faults to major plate boundaries or to the distance from the African (Nubian) – Aegean collision front. This paper will focus on the understanding of the intraplate deformation, far from the Aegean plate boundaries, as this is expressed by a series of active rifts dissected by primarily normal faults in the central Greece. These rifts are well known as, the Corinth, Saronikos, Euboea and Sperchios. The scope of this study is to understand the deformation between the Corinth and Sperchios rifts.

The Corinth rift is a rapidly expanding intra-continental extensional rift, involving active normal faults of ENE-WSW to WNW- ESE strike. Geological mapping and morphotectonic study re-populate the south gulf area with high (4 mm/yr) and the north one with low slip-rate (0.1-0.2 mm/yr). Similarly, in the area located between the Corinth and Euboea Gulfs, active normal faults are bimodal in trend. These are ENE to NE trending (Livadostras fault zone) or almost E – W trending (Kaparelli, Erithres and Leontari faults). Palaeoseismological and morphotectonic studies performed in this area suggest slip rates in the order of 0.3 mm/yr. This area north of the Corinth rift extending up to Sperchios area is dominated by spectacular active normal faults (Delphi, Atalanti, Agios Konstantinos and Thermopylae faults). Thus, the northernmost fault structure seems to deviate from what is thought to be the case of an area of homogenous deformation at back-arc setting or located at the interaction of the Cephalonia Transfer Fault and the North Anatolian Fault.

In summary faults south or north of the Corinth rift show remarkable similarities in their orientations but are characterized by a progressive reduction of their slip rate. Considering the reduction of slip rates from southwest to northeast we propose that the rapid extension is related with the almost flat African (Nubian) plate below Peloponnese that deepens strongly at Corinth area. Over the steeply dipping plate the slip rate of the faults is low expressing a rather low strain area.