Geodetic analysis of the tectonic crustal deformation pattern in the North Aegean Sea, Greece

The satellite geodesy contribution is decisive for active tectonics determination, as it provides both qualitative and quantitative evidence of a tectonically active region. North Aegean Sea is characterized by intense tectonic, and hence, seismic activity. To estimate the tectonic regime, 7-year primary raw geodetic datasets are implemented, deriving from 32 permanent GPS/GNSS stations. After applying a 30-s sampling rate and ETRF2000 as reference frame, the data are processed using the triangulation methodology, i.e. setting three GPS/GNSS stations each time as the three triangle vertices, from which the barycentre is determined. On each of the 404 barycentres, four-strain quantities are calculated: MAXIMUM and Minimum Horizontal Extension (MaxHE), Total Velocity (TV), Maximum Shear Strain (MaxSS), and Area Strain (AS). The parameterized barycentres are geostatistically processed by applying the Kriging interpolation technique to visualize the pattern of each strain quantity. The results reveal intense crustal deformation in the northern Aegean, directly associated with tectonic activity and, furthermore, plate tectonics. The prevailing shear along with the most dominating tectonic structure of the North Aegean Sea, i.e. the western continuation of the North Anatolian Fault (NAF) in the form of the North Aegean Trough and Basin (NAT and NAB, respectively), is consistent with all the previous geodetic, tectonic and seismological results.