THE CRUST AND UPPER MANTLE STRUCTURES IN CENTRAL ANATOLIA, TURKEY, CONSTRAINED BY GRAVITY AND SEISMIC DATA

Central Anatolia, located in the eastern Mediterranean Region, is tectonically active due to the westward escape of the Anatolian plate between the North and East Anatolia Fault zones and subduction of the Cyprus slab along the Cyprus arc. In recent years, Western and Eastern Anatolia have been subjected to gravity and seismic studies to identify the crust and upper mantle structures of the subduction and collision zones in Turkey and surrounding regions. The crust in western Anatolia is thinner than the average continental crust and it is thermally affected by slab break off events. The eastern Anatolian lithosphere is underplated by low-velocity asthenospheric material in the uppermost mantle following slab break off events and lithospheric delamination in the region. However, the crust and upper mantle structure in central Anatolia is not well established.

This study aims to determine the crust and upper mantle structures of central Anatolia along seven profiles between 30-38°E Longitude and 32-40°N Latitude based on gravity data from the EIGEN-6C4 geopotential model. We constructed density models of the crust and upper mantle structure of central Anatolia. The models are constrained by velocities from seismic tomography, receiver function, and earthquake hypocenters.

Our preliminary result along the longitude 31°E suggests that the Cyprus slab subducts with almost 45 degree angle. The presence or absence of lithospheric delamination and/or slab break off event in central Anatolia will be interpreted once all gravity profiles are modeled. The evidence for lithospheric delamination and/or slab break-off event might be relatively thin lithosphere and thermally altered material in the upper most mantle, which is relatively low in density and velocity.