GEODETIC MEASUREMENTS IN THE AEGEAN SEA REGION FOR THE DETECTION OF CRUSTAL DEFORMATION

Abstract

Greece and the Aegean Sea form part of one of the most rapidly deforming areas of the Earth's surface and are characterized by a high level of intra-plate seismicity in comparison to neighboring regions. AEGEANET is a geodetic network that we have established in order to consistently measure the geodetic strain in the broader Aegean Sea region, including parts of the Greek mainland and spanning several areas of known fault systems. Our measurements so far span approximately 4- and 42-year periods up to 1997 using a combination of old triangulation/trilateration-derived coordinates and repeated GPS observations at various subsets of the stations of this network. The observed displacements reflect the present-day tectonic deformation of the region, showing more than one meter of north-south extension across the network. The crust in this region appears to contain a few relatively rigid blocks separated by more rapidly deforming zones. This conclusion is Supported by the velocity and strain fields that we have estimated for six sub-regions, which provide a more detailed view of the crustal deformation in this region.