Mantle lithosphere, asthenosphere and transition zone beneath Eastern Anatolia

By using P and S wave receiver functions and P and S wave travel time residuals, we have found velocity models for 16 seismograph stations in Eastern Anatolia. Our study is focused mainly on the mantle lithosphere, asthenosphere and transition zone. The volcanism and uplift of the Eastern Anatolia Plateau are thought to be related to the Bitlis slab break off and delamination of the continental lithosphere. Sinking cold slab and lithospheric drips can reduce temperature in the mantle transition zone (MTZ) by up to a few hundred degrees C. However, our analysis of seismic data provides no robust evidence of significant cooling of the transition zone. In the mantle immediately above the 410-km discontinuity there is a pronounced low S wave velocity layer that may be a source of the volcanism in the study region. Another low velocity layer is present at the base of the MTZ. The obtained S wave velocity models of the upper mantle can be divided into three groups. In the first group, the lithosphere—asthenosphere boundary (LAB) is at a depth of ~ 60 km. In the second group, the LAB is at a depth from 90 to 100 km. In the third group, the mantle lithosphere is practically absent. On a scale of our analysis there is no clear correspondence between the obtained mantle velocity models and the volcanism (< 23 Ma) exposed at the surface. Only the models of the first group are well represented in the neighboring Central Anatolian Plateau.