Active faults in the Anatolian-Aegean plate boundary region with Nubia

Abstract

Convergence of the Africa, Arabia, and Eurasia plates and the westward escape of Anatolia have resulted in an evolving plateboundary zone in the Eastern Mediterranean. The current location and nature of the plate boundary between the Anatolian and theAfrican plate is difficult to trace due to the scattered crustal earthquakes and the absence of deep ones. We examine various types andlocations for the plate boundary as constrained by seismicity, seismic reflection studies, tomographic studies, and geodetic measurementsand we use a spherical plane stress finite element model to test these possibilities. In our regional model, we impose the convergenceof Africa, Arabia, and stable Eurasia by applying GPS-derived velocities in the far-field, as well as the roll-back of the Hellenic trenchto solve for regional deformation. Model velocity and stress fields are compared with GPS-derived velocities and stress directionsfrom focal mechanism solutions. We find that the plate boundary via the Pliny and Strabo trenches, the Anaximander Mountains, theEratosthenes Seamount collisional segment, and the Latakia-Larnaka ridges gives the best fit to the data. The Anaximander Mountainsplate boundary has both down-dip and strike-slip motions, and the Latakia segment is pure strike-slip. The Cyprus subduction contactis 42% locked. From a combined analysis of indicators for long-term deformation (predominantly slip-rates on major faults) and modelresults we infer that this southern plate boundary configuration may have existed since the Late Pliocene.