GNGTS 2014 - Atti del 33° Convegno Nazionale

Benkhelil et al.�� .; 2011: �� Seismic atlas of the “Messinian salinity crisis” markers in the Mediterranean and Black Seas �� Paris . Memoire de la Société Géologique de France, 179 , 71 pp. ISBNs:2853630978, 9782853630979. Maillard A., Mauffret A.; 2013: Structure and present-day compression in the offshore area between Alicante and Ibiza Island (Eastern Iberian Margin). Tectonophysics, 591 , 116-130. Mauffret A., Frizon de Lamotte, D., Lallemant S., Gorini C. and Maillard, A.; 2004: E-W opening of the Algerian Basin (Western Mediterranean) . Terra Nova, 16 , 257-264. Rehault J. P., Boillot G. and Mauffret A.; 1984: The Western Mediterranean Basin geological evolution . Mar. Geol., 55 , 447-477. Sabat F., Roca E., Munoz A., Verger J., Santanach P., Sans M., Masana E., Estevez A. and Santisteban, C.; 1995: Role of extension and compression in the evolution of the eastern marfin of Iberia: the ESCI-Valèntia Trough seismic profile . Rev. Soc. Geol. Espana, 8(4), 431-448. Speranza F., Villa I.M., Sagnotti L., Florimdo F., Cosentino D., Cipollari P., and Mattei M.; 2002: Age of the Corsica-Sardinia rotation and Liguro-Provençal Basin spreading: new paleomagnetic and Ar/Ar/ evidence . Tectonophysics, 347 , 231-251. Active tectonics and seismic/tsunami hazard in the Messina Straits region: the Ionian and Alfeo/Etna fault systems A. Polonia 1 , L. Torelli 2 , L. Gasperini 1 , S. Romano 1 , S. Vaiani 3 , A. Artoni 2 1 ISMAR, Istituto di Scienze Marine, U.O. Geologia Marina, CNR, Bologna, Italy 2 Dip. di Fisica e Scienze della Terra “Macedonio Melloni”, Università degli Studi di Parma, Italy 3 Dip. di Sc. Biol., Geol. e Amb., Univ. of Bologna, Italy Abstract. �� The Messina Straits region is one of the most seismically active areas in the central Mediterranean Sea where different interacting fault systems produce a complex pattern of shallow deformation. It is part of the CalabrianArc subduction complex, a narrow subduction- rollback system related to Africa/Eurasia plate convergence which has been shaped by rollback processes, slab tearing and recent plate boundary re-organization. Shortening in the accretionary wedge is taken up along the outer deformation front and out- of-sequence thrust faults (splay faults). Transtensive deformation, on the other hand, accounts for margin segmentation along transfer tectonics systems bounding different margin segments. Transfer faults represent the shallow expression of deeply rooted processes at the slab edge. One of these structures is the NNW-SSE trending transtensive fault system located East of the Malta Escarpment from the Alfeo seamount to the Etna volcano (Etna-Alfeo fault system). The second major transfer fault system is represented by a NW-SE fault system dissection the whole subduction complex from the Messina Straits region to the Ionian abyssal plain (Ionian fault system). Newly acquired geophysical data (CALAQUAKE Urania cruise, May 2014), reveal that the deformation zone between the two lobes of the accretionary wedge displays fresh seafloor scarps and mud volcanoes suggesting it represents an active tectonic boundary and a deep fluid/mud conduit. We propose that this discontinuity accommodates a recent plate boundary re-organization in the Ionian Sea, connecting the compressive belt in northern Sicily to the Hellenic Arc system and dissecting the CA subduction complex. This �� deformation zone accommodates differential movements of the Calabrian and the Peloritan portions of CA and can explain the NW-SE extension observed in the straits of Messina as well as the relative motion between Calabria and NE Sicily. The complex tectonic setting of the central Mediterranean region, irregular plate boundaries and the final stage of subduction processes produce dynamic topography of the Calabrian Arc and very high uplift rates of the coastal mountain ranges, accompanied with a great sediment discharge to the continental margins. This implies a strong interplay between active tectonics, seismicity, mass flows and tsunami generation in the Messina Straits region where more than GNGTS 2014 S essione 1.2 163