A New Velocity Field Of Greece Based On Seven Years (2008-2014) Continuously Operating Gps Station Data

Greece is characterized by complex and intense geodynamics, because it is located between the collision boundaries of two tectonic plates (Africa-Nubia and Eurasia), with major active tectonic features such as the Hellenic Arc, the Anatolian fault in North Aegean Trough and the Kefalonia fault in the Ionian Sea. GPS is a well-established tool for geophysical research purposes, because it is able to provide continuous measurements for monitoring displacements of the Earth's crust. The aim of the present study is to create a modern and improved geodetic velocity field for Greece using GPS observations from continuously operating reference stations. The new set of geodetic velocities is derived from the processing of 7 years (2008-2014) of daily GPS data, using 155 stations distributed in the broader Greek territory and 30 IGS-EPN GPS stations. The GAMIT/GLOBK software package was used to process the GPS measurements. The results are expressed in the ITRF2008 reference frame. The analysis showed that the northern region of Greece is the most stable and has identical movement with the Eurasian plate in contrast with the region of the southern part and the Aegean Sea. According to the results, the estimated horizontal geodetic velocities show completely different pattern between northern and southern Greece with significant differences both in magnitude and direction. The derived site values were used for a velocity grid creation in order to predict velocities within the Greek area and to enforce proper realization of GNSS reference systems in Greece.