INTERMEDIATE DEPTH SEISMICITY IN THE AEGEAN DEFINED BY TELESEISMIC DATA

The most reliably located intermediate depth earthquakes in the Aegean area, selected from the International Seismological Centre Catalogue, deepen towards the internal part of the Hellenic arc and reach a maximum depth of 150 km. During the last 20 years, most have occurred at the eastern and western ends of the arc, and very little activity is found in the middle area north of Crete. The seismic zone defines a contorted slab of lithosphere. In the western part a very shallow dipping seismic zone extends 200 km northeast from the trench and then steepens abruptly at depths of about 50-80 km, eventually reaching dips of 45-degrees. The 100 km and 150 km isodepth contours are not parallel to the Hellenic trench. In the western part, the geometry of the slab is more consistent with a south-southwestward translation of the Aegean arc with respect to the African plate than with a rotation around a pole located close to the Aegean region.