Three-dimensional numerical modeling of contemporary mantle flow and tectonic stress beneath the Central Mediterranean Alik Ismail-Zadeh a,b,c, ⁎, Abdelkrim Aoudia c , Giuliano F. Panza c,d a Geophysical Institute, University of Karlsruhe, Hertzstr.16, Karlsruhe 76187, Germany b MITPAN, Russian Academy of Sciences, Profsoyuznaya str. 84/32, Moscow 117997, Russia c Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste 34014, Italy d Department of Earth Sciences, University of Trieste, via E. Weiss 4, Trieste 34127, Italy abstract article info Article history: Received 26 September 2008 Received in revised form 2 July 2009 Accepted 17 July 2009 Available online 24 July 2009 Keywords: Deviatoric stress Viscous flow Buoyancy Finite-element modeling Central Mediterranean The structure, density and effective viscosity of the crust and uppermost mantle beneath the Central Mediterranean influence lithospheric deformation, mantle flow, and tectonic stress state. To estimate the contribution of buoyancy forces to regional dynamics, three-dimensional finite-element models are devel- oped to determine contemporary uppermost mantle flow and tectonic stresses. We use density models for the crust and uppermost mantle derived from S-wave seismic velocities and constrained by gravity data. The viscosity model is constrained by the observed strain rate and regional heat flow data. The modeled movement of the uppermost crust is consistent with the northeast-oriented motion of the lithosphere and is in an agreement with the geodetic measurements. The modeled flow patterns of the lower crust and uppermost mantle are consistent with the regional observations. The models predict (i) northwest-oriented movements beneath the southeast part of the Adriatic Sea region, (ii) the northeastern subduction beneath the western part of the Adriatic Sea, (iii) the upwelling beneath the Tyrrhenian Sea and its eastern coast, (iv) the western movement of the Ionian Sea sub-plate, and (v) the subduction beneath the western Calabria region. Our models predict also a distinct compressional regime along the northeast part of the Italian peninsula and to the east of Sicily, and a tensional regime beneath the Tyrrhenian Sea, Umbria–Marche region, and Ionian Sea. The predicted tectonic stress regimes in the northern and central Apennines are in agreement with stress regimes derived from earthquake fault-plane solutions. Changes in the predicted crustal stress pattern and magnitude are likely to be caused by buoyancy-driven mantle circulation beneath the region rather than by gravitational potential energy differences in the crust itself. Based on the model results, we conclude that the buoyancy forces play an important role in the contemporary tectonics of the region. © 2009 Elsevier B.V. All rights reserved. 1. Introduction The Central Mediterranean geology has been mainly shaped by the interplay between the Eurasian and African plates. The extremely variable structure of the lithosphere–asthenosphere system in the region is the result of its complex geodynamic history. The Cenozoic to Quaternary regional evolution has been marked by the coexisting compression and tension developed between converging continental plates (e.g., Doglioni et al., 1999; Faccenna et al., 2004). However, the rate of convergence between the plates has been less significant compared to the east–west extension (e.g., Mantovani et al., 2002). The latter has been migrating from west to east and has been posi- tioned behind a compression front migrating in the same direction. As a consequence, a number of extensional basins have formed behind the Apennines–Maghrebian compression front. Orogenic magmatism followed the eastward migrating extensional regime, becoming younger from Sardinia (Oligo-Miocene) to the Tyrrhenian Sea floor and to the Southern Tyrrhenian Sea (Peccerillo, 2003, 2005 and references therein). The eastward migration of the Apennines compression front is accompanied by a fragmentation of the Apennines lithosphere, with progressive ending of the active subduction zone from the Northern Apennines to the south. The fragmentation of the Apennines litho- sphere created sectors that had an independent evolution (Locardi, 1993; Sartori, 2003). This may explain the variable lithosphere– asthenosphere structure in the region. Several authors suggested continuous west-dipping subduction of the Adriatic and Ionian plates beneath the southern margin of Europe (e.g., Carminati et al., 1998; Doglioni et al., 1999; Faccenna et al., 2004 and references therein). This follows an older subduction process, having an opposite dipping direction (e.g., Peccerillo and Martinotti, Tectonophysics 482 (2010) 226–236 ⁎ Corresponding author. Geophysical Institute, University of Karlsruhe, Hertzstr.16, Karlsruhe 76187, Germany. Tel.: +49 721 608 4610; fax: +49 721 71173. E-mail address: alik.ismail-zadeh@gpi.uni-karlsruhe.de (A. Ismail-Zadeh). 0040-1951/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.tecto.2009.07.013 Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto