Determination of the displacements along the Tuzla fault (Aegean region-Turkey): Preliminary results from GPS and precise leveling techniques

Abstract

Both seismological and geodynamic studies emphasize that the Aegean region is deforming internally mainly under pure shear stress and rotating in an anti-clockwise direction relative to the Eurasia plate. The Aegean region is seismically the most active region in western Anatolia, which comprises the Hellenic Arc, Greece, and western Turkey. Izmir is the third largest city in Turkey, with a population about 2.7 million in 2010. The Tuzla fault has a particular importance in terms of its proximity to the city of Izmir and its seismic activity. The Tuzla fault has NE–SW trending lineaments and lies between the towns of Menderes and Cape Doganbey.This study intended to investigate crustal deformation and relative displacement along the Tuzla fault and Izmir Bay by two different geodetic techniques: GPS and precise leveling. Toward this aim, a geodetic network consisting of 16 points has been established. The first GPS observation campaign and precise leveling measurements were performed in 2009, and the second set of measurements was performed in 2010. The data collected by the GPS campaigns were processed with GAMIT/GLOBK software. The displacements inferred from GPS data are between 21mm/yr and 25mm/yr with respect to Eurasia as the fixed reference frame. In addition, the precise leveling results show that there is a vertical displacement in the region of around 7mm along the fault, which is higher than expected during a nine-month interval.