WEGENER 2010 15TH General Assembly of Wegener, İstanbul, Turkey, 14 - 17 September 2010, pp.1
Since 1995, a consistency has been tried to find out between fault networks suggested by active tectonic researchers and GPS velocities. Geodetic models related to active faults of Marmara were critically reviewed by considering measurement properties of station networks and modelling methods. According to GPS velocity models, a clear inconsistency is obvious between GPS measurements and generally accepted active fault network and its simplified variations based on pullapart model. Geodesists insistently point out that in the Marmara, most of the deformation occurs in the north and along a narrow ~E-W oriented single dextral fault trace from İzmit to North Aegean Trough. This simple continuous fault trace delineates the boundary between Anatolia and the Eurasian plate with ~25mm/yr velocity. On the other hand, dilatation rates have inconsiderable amounts based on GPS velocity fields. So extensive extension constructing a basin in any way is lack in the Marmara region. No extension related to the Aegean region is needed to explain opening of the Marmara basin with pull-apart model but any extension produced by the model is expected to be observed around the basin at least in İzmit bay. In addition, an acceptable consistency in a model should be available between pull-apart fault network and GPS velocities. For this reason, the pull-apart model that is used for explaining the active formation of the Marmara basin and draw active fault lines should be critically questioned.