Active faults and historical earthquakes in the Messina Straits area (Ionian Sea)

Abstract

Abstract. The Calabrian Arc (CA) subduction complex is located at the toe of the Eurasian Plate in the Ionian Sea, where sediments resting on the lower plate have been scraped off and piled up in the accretionary wedge due to the African/Eurasian plate convergence and back arc extension. The CA has been struck repeatedly by destructive historical earthquakes, but knowledge of active faults and source parameters is relatively poor, particularly for seismogenic structures extending offshore. We analysed the fine structure of major tectonic features likely to have been sources of past earthquakes: (i) the NNW-SSE trending Malta STEP (Slab Transfer Edge Propagator) fault system, representing a lateral tear of the subduction system; (ii) the out-of-sequence thrusts (splay faults) at the rear of the salt-bearing Messinian accretionary wedge; and (iii) the Messina Straits fault system, part of the wide deformation zone separating the western and eastern lobes of the accretionary wedge.Our findings have implications for seismic hazard in southern Italy, as we compile an inventory of first order active faults that may have produced past seismic events such as the 1908, 1693 and 1169 earthquakes. These faults are likely to be source regions for future large magnitude events as they are long, deep and bound sectors of the margin characterized by different deformation and coupling rates on the plate interface.

Integrating geologic fault data into tsunami hazard studies

“…The dip then increases again at a depth of 50 km, more or less beneath the Tyrrhenian coast. Constraints on the slab interface geometry in this area are provided essentially by seismic profiles (Finetti, 2005;Minelli and Faccenna, 2010;Polonia et al, 2011Polonia et al, , 2012. V p and V s tomography reveals the presence of a high velocity anomaly beneath the Tyrrhenian Sea as deep as 600 km (Piromallo and Morelli, 2003;Chiarabba et al, 2008;Giacomuzzi et al, 2011).…”

“…Recent seismic profile interpretations Van Dijk et al, 2000;Finetti, 2005;Minelli and Faccenna, 2010;Polonia et al, 2011) revealed that the accretionary wedge internal structure has two distinct lobes, the eastern lobe and western lobe, affected by large splay faults [C2-C6] deemed to be potentially seismogenic by Polonia et al (2011Polonia et al ( , 2012. These splay faults reach the subduction plane at a depth of 15-20 km in the eastern lobe and around 12 km in the western lobe with NW dipping plane of less than 20 • .…”

“…Argnani et al, 2012). Polonia et al (2011Polonia et al ( , 2012 argue that another NW-SE shear zone, located about 70 km east of the Malta Escarpment, deforms the overlying younger deposits of the accretionary wedge and should be considered as the major tectonic feature.…”

The limits of seaward spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

“…Nevertheless, the nature and origin of the Ionian basin crust is still a matter of debate (e.g. Polonia et al 2012;Gallais et al 2013). Due to its regional importance as a deep-seated weakness zone, a link between the Malta Escarpment and Mt E ' f c h b , as the maximum uplift rates in the regional setting of Mt Etna are related to the upthrown side of the Malta Escarpment (Rust and Kershaw, 2000).…”

Seismicity at the northeast edge of the Mexican Volcanic Belt (MVB) and activation of an undocumented fault: the Peñamiller earthquake sequence of 2010–2011, Querétaro, Mexico

“…Examples of similar documented events in other parts of the world where the seismic activity is too low are given in Polonia et al (2012), Vipin et al (2009) andDel Gaudio et al (2009). In this study we present a detailed analysis of the seismic source parameters of events of the Peñamiller sequence, monitored during the first three months of 2011.…”