Authors: MICHAEL FLOYD, ROBERT KING, DEMITRIS PARADISSIS, HAYRULLAH KARABULUT, SEMİH ERGİNTAV, KOSTAS RAPTAKIS, Robert Reilinger

Abstract: GNSS observations in and around the Aegean Sea, Peloponnese, and western Turkey are sufficiently precise and densely spaced to provide an image of the deformation associated with the Hellenic subduction zone. To isolate deformation associated with the plate boundary, we use GNSS secular velocities and shallow earthquake locations to determine an upper plate reference frame with low internal deformation (<2 mm/yr) that includes a large area of the central and western Aegean. We interpret upper plate deformation as resulting from stronger coupling on the subduction plate interface beneath western Crete than on the western or eastern segments of the Hellenic subduction zone, and the geometry of the subducting plate along-strike. If the long-term tectonic extension of the Aegean upper plate counteracts some of the contractional deformation signal from elastic strain accumulation on the subduction interface, as measured at the surface, the coupling coefficient may be as high as 40% around western Crete, although this is the upper limit.

Keywords: GNSS, tectonics, Hellenic subduction zone, Aegean

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