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Orographic reliefs are continuously created and modified in active continental tectonic settings, influencing the drainage pattern and interacting with it. It is not uncommon that stream capture occurs in these settings, causing major rearrangement of river courses. This process often produces a geomorphological feature known as wind gap, i.e. a gap through which a stream once flowed but that is now abandoned and dry as a result of the capture. Analizing a high resolution 3D seismic data set, kindly made available by ENI S.p.A., we discovered a similar feature in the Ionian offshore of the Crotone peninsula, northern Calabria. This underwater region is characterized by intense tectonic activity that is partly controlled by the occurrence of a mobile substrate, possibly overpressured shales. The relevant uplift affecting the nearby Calabria onshore can also contribute to promote gravitational instability. In this setting the "wind gap" is represented by a stretch of a downslope weakly incised channel that has soon been abandoned as a result of the growth of a tectonic structure. The course of the new submarine channel runs sub-parallel to the coast for a long strecth, before taking a downslope trajectory. The present-day submarine channel is deeply incised, showing at least two main phases: a deep valley incision containing an axial valley with a much lower relief, which likely represents the current route of turbidite flows. The main channel valley results from the major erosional episode that affected the continental slope offshore northern Calabria. The limited incision in the abandoned channel strecth suggests that drainage rearrangement occurred in the very early stage of channel incision. Therefore, the estimated age of the tectonic deformation that is responbile for originating the "wind gap" can offer a useful hint on the timing of onset of erosion in this area.

Ground motion prediction is one of the main goals in seismic hazard assessment. Empirical ground motion prediction equations may fail to reproduce the complexity of ground shaking in complex 3D media and therefore the use of full waveform modelling is increasingly adopted to model ground shaking. The knowledge of the 3D crustal structure in terms of geometries of the main discontinuities and velocities is fundamental to model wave propagation. However, we often lack detailed geological and geophysical information to build reliable models.We exploit here a large set composed of high-resolution 2D and 3D seismic data and of about 40 wells with stratigraphic and velocity information, both onshore and offshore, to constrain a 3D crustal velocity model in a sector of the Calabrian accretionary prism (southern Italy). We interpret the main reflection discontinuities and constrain their depth at all available wells in the study area and we use well’s check-shots and velocity data to estimate interval-velocities of the main stratigraphic units. We then combine all depth and velocity information into a regional 3D crustal velocity model of the first 8-10 km. This is subsequently extended to a depth of ~50 km using available regional crustal models to obtain the final model used for ground motion simulation.We implement our crustal model in the spectral-element code SPECFEM3D_Cartesian to simulate wave propagation in the 3D velocity model honoring surface topography. This allows reconstructing the low-frequency part of the waveforms (up to ~1 Hz), which is then combined with high-frequency seismograms obtained with a stochastic method following the hybrid broadband simulation approach by Graves and Pitarka (2010).We evaluate the goodness of our model by simulating real earthquakes and comparing simulated and recorded waveforms at the available seismic stations in the area. We compare the results from our 3D model with the ones obtained using a local tomography model and the European crust model EPcrust. The maps of ground motion obtained from the simulated broadband waveforms are then compared with empirical ShakeMaps. These results will also be useful for earthquake scenario calculations, by simulating potential seismic sources identified from structural analysis of geological and seismic data.

The Calabrian accretionary prism is the result of a complex interaction between subduction-related tectonics and sedimentation, active since the Eocene. The limited seismicity recorded in recent years in the area appears mostly associated to the subduction interface and could reflect either a weak subduction coupling or a slow subduction rate. Nevertheless, recent intense deformation and uplift of the seafloor has been observed within the accretionary prism.The analysis of multichannel 2D and high-quality 3D seismic data, morphobathymetric data and instrumental seismicity, allows defining and characterizing both the deeper and shallower tectonic deformation affecting the northeastern sector of the Calabrian accretionary prism. Besides the uppermost thrust fault of the Calabrian accretionary prism, that outlines the Crotone promontory, the shallow tectonic pattern of the prism is characterized by a belt of broad flat-topped anticlines, and a set of minor narrow structures, mainly NNW-SSE to N-S oriented, that present a variable relationship with the underlying main thrust faults. The uppermost sedimentary strata within the anticlines are affected by numerous small-scale extensional faults, not rooted at depth, likely due to outer-arc extension above uplifted depocenters. In places, the inversion of basin-bounding faults is also visible. More regularly spaced and cylindrical NW-SE anticlines are also observed in the Gulf of Taranto, in the outer sector of the accretionary prism, where a thrust/back-thrust tectonic style is present. The origin of the anticlines varies within the overall set and reflects the long-term tectonic evolution of the accretionary prism, with the oblique docking of the Calabrian accretionary prism onto the Apulian Escarpment as a key feature.

The Messinian primary gypsum sequence, formed during the first stage of the salinity crisis in the Caltanissetta basin (Sicily), is characterized by a high degree of disruption and deformation. The primary gypsum occurs as huge (up to 3 km large and up to 250 m high) tilted blocks, detached from their stratigraphic base, floating within a matrix of folded shales and clastic gypsum. This association represents a giant chaotic unit lying unconformably on the Gela Nappe, the youngest structural unit of the Maghrebian fold-and-thrust belt. The origin of the deformations affecting the Primary Lower Gypsum unit is still debated; in the past they have been related to intra-Messinian tectonics or to the collapse of primary gypsum platforms due dissolution of interbedded to halite. Our study on the distribution, size and bedding of the gypsum blocks reveals a pattern similar to that of modern giant submarine mass-transport deposits, which may have been triggered by a combination of active tectonics and sea-level change, and favored by the strong mechanical contrasts of the involved units. The chaotic unit shows a downslope evolution from the south, characterized by elongated blocks with their main axes parallel to the inferred slide headwall (NW-SE oriented), to intermediate and distal areas, where the blocks become progressively smaller in size with their main axes parallel to the flow (SW-NE). We identify the source area as either a shallow evaporitic basin above the Gela Nappe or on the Pelagian foreland ramp. A general implication for the Messinian salinity crisis is that no primary gypsum was deposited in deep water basins during the first stage; instead, during the second stage, large gypsum blocks collapsed from the basin margin and were mass-transported into a deeper water setting, where halite was depositing.

At 3:54 night time on November the 26th the city of Durres in Albania was hit by an earthquake of Mw 6.2, followed in the next 4 hours by three additional earthquakes with Mb > 5.0. These earthquakes, part of a sequence that continued with much reduced intensity until mid December, caused severe damages in Durres and the adjacent region, counting a final human toll of about 50 casualties and over 2000 injuried. The historical catalogues show that Albania has been affected by over 10 relatively strong earthquakes (Mw> = 6.0) in the last 200 years (Kiratzi and Dimakis 2013), testifying to an important seismic history.The focal mechanisms of the Durres earthquakes show compressive fault planes placed at ca. 10 km depth. These earthquakes are part of a belt of compressional earthquakes that borders to the east the southern Adriatic, including the strong Montenegro earthquake (Mw 7.1) of April 1979, indicating that shortening is currently ongoing at the front of the southern Dinarides and Hellenides.The geological structure of Albania, at the junction between the Dinarides and the Hellenides, shows structural complexities that have their roots in the Mesozoic paleogeography of the region (Argnani, 2013). The front of the Albanian fold-and-thrust belt extends to the sea, where it has been studied thanks to some seismic acquisition campaigns aimed at investigating the geology of the Adriatic Sea (Argnani 2013). This sector of the thrust front is characterized by the presence of important back thrusts, which are correlated to the spatial distribution of the Mesozoic domains of carbonate platforms and pelagic basins. In the sector facing the southern Adriatic basin the presence of a large thickness of Oligocene-Quaternary clastic sediments filling the foredeep promotes the development of triangle zones and backtrusts. The basal thrust of the triangle zone system affects Mesozoic carbonates at an estimated depth of 10-15 km (Fantoni and Franciosi, 2010) and appears to be the source of the Durres earthquakes. A similar structural setting can be envisaged for the Montenegro earthquake of 1979, as the offshore structures show a continuity, although a substantial change in strike occurs across the trend of the Shkoder-Peja line. A large lateral displacement of the internal units occurs along the Shkoder-Peja transversal line, which marks the junction between the Hellenides and the Dinarides. The shallow water limestones of the more external Kruja domain, however, are not laterally offset. Palaeomagnetic results indicate that the Miocene-Pliocene clock-wise rotation of the western arm of the Aegean opening was accomplished just south of the Shkoder-Peja line; these rotations impose an overall change in strike of the outer thrusts, although the frontal structures are specifically affected by the nature of the Mesozoic domains entering the thrust system.ReferencesArgnani A. (2013) -. Ital. J. Geosci., 132, 175-185.Fantoni R., Franciosi R. (2010) - Rend. Fis. Acc. Lincei 21, S197–S209.Kiratzi A., Dimakis E. (2013) - Ital. J. Geosci., 132, 186-193.

The recent release of a large number of subsurface geological data by the Italian Minister of Economic Development, including boreholes and seismic profiles, provided the occasion for a new assessment of the deposits associated with the Messinian salinity crisis (MSC) in the Adriatic foreland basin system and a new integration with the outcropping successions of the Apennines. In particular, the study of the Messinian evaporites allowed to reconstruct a new detailed palaeogeographic and palaeobathymetric framework for all the stages of the crisis. We identified the largest evaporitic marginal basin ever described for the Mediterranean hosting the precipitation of the primary shallow-water gypsum deposits (PLG, Primary Lower Gypsum) during the first stage of the crisis. During the second and third stages of the crisis, the PLG basin underwent uplift and erosion and the evaporite accumulation moved to the deeper part of the basin and was characterized by the deposition of the Resedimented Lower Gypsum unit including clastic evaporites, recycling the PLG ones, primary halite and terrigenous deposits. The distribution of the different evaporitic facies, was the basis for an improved reconstruction of the upper Miocene tectonic evolution of the Apennines thrust belt. Our results show a clear separation between shallower depocenters, located in the wedge-top and in the Adriatic foreland basins and characterized by MSC stage 1 PLG deposition, and deeper-water ones, located in the Adriatic foredeep and close to the Calabrian Arc, where MSC stage 2 terrigenous and gypsum-bearing clastic deposits and primary halite accumulated.

To obtain a 3-D crustal density and shear-wave velocity structure beneath the Po plain, we exploit seismic records gathered from 2006 to 2014 and Bouguer gravity data assembled for the last estimation of the Italian Geoid. 2-D maps for both Love and Rayleigh fundamental mode at periods between 4 and 20 s are obtained applying a tomographic inversion. The defined local dispersion curves are then jointly inverted using a linearized scheme to obtain a 3-D isotropic shear-wave velocity model across the Po plain region. The model, transformed into density through a priori velocity-density relationships, is then the input of the Sequential Integrated Inversion algorithm, which enables us to recover a new 3-D density-shear wave velocity coupling and inferences on the lithology and tectonics. Low and fast S-wave velocities are highlighted for the shallow Pliocene–Quaternary sediments along the foredeep, in front of the Northern Apennines, and for the presence of limestone units in the upper crust, respectively. Whereas sediment trends seem to be consistent with the results obtained, the Mesozoic carbonates, which are inherently characterized by high variability, are less resolved. A major result is the recovery of a high speed (3.3 km/s) - density (2.2 kg/m3) structure in the upper crust (6–10 km) localized beneath the arcuate Po plain thrust front expanding from the external margin of the Ferrara arc toward the Alps and the Adriatic Sea. At the boundaries of this brittle body, we locate earthquakes of the Emilia 2012 seismic sequence and the historical seismicity. Mapping lateral discontinuities in density and shear wave velocity could provide insights in defining strengthening and weakening zones, and in focusing on transition zones often prone to earthquakes.

South-eastern Sicily has been affected by large historical earthquakes, including the 11 January 1693 earthquake, considered the largest magnitude earthquake in the history of Italy (Mw = 7.4). This earthquake was accompanied by a large tsunami (tsunami magnitude 2.3 in the Murty-Loomis scale adopted in the Italian tsunami catalogue by Tinti et al., 2004), suggesting a source in the near offshore. The fault system of the eastern Sicily slope is characterised by NNW–SSE-trending east-dipping extensional faults active in the Quaternary. The geometry of a fault that appears currently active has been derived from the interpretation of seismic data, and has been used for modelling the tsunamigenic source. Synthetic tide-gauge records from modelling this fault source indicate that the first tsunami wave polarity is negative (sea retreat) in almost all the coastal nodes of eastern Sicily, in agreement with historical observations. The outcomes of the numerical simulations also indicate that the coastal stretch running from Catania to Siracusa suffered the strongest tsunami impact, and that the highest tsunami waves occurred in Augusta, aslo in agreement with the historical accounts. A large-size submarine slide (almost 5 km3) has also been identified along the slope, affecting the footwall of the active fault. Modelling indicates that this slide gives non-negligible tsunami signals along the coast; though not enough to match the historical observations for the 1693 tsunami event. The earthquake alone or a combination of earthquake faulting and slide can possibly account for the large run up waves reported for the 11 January 1693 event.

This study presents new geological and seismological data that are used to assess the seismic hazard of a sector of the Po Plain (northern Italy), a large alluvial basin hit by two strong earthquakes on May 20 (M-W 6.1) and May 29 (M-W 6.0), 2012. The proposed interpretation is based on high-quality relocation of 5369 earthquakes ('Emilia sequence') and a dense grid of seismic profiles and exploration wells. The analyzed seismicity was recorded by 44 seismic stations, and initially used to calibrate new one-dimensional and three-dimensional local Vp and Vs velocity models for the area. Considering these new models, the initial sparse hypocenters were then relocated in absolute mode and adjusted using the double-difference relative location algorithm. These data define a seismicity that is elongated in the W-NW to E-SE directions. The aftershocks of the May 20 mainshock appear to be distributed on a rupture surface that dips similar to 45 degrees SSW, and the surface projection indicates an area similar to 10 km wide and 23 km long. The aftershocks of the May 29 mainshock followed a steep rupture surface that is well constrained within the investigated volume, whereby the surface projection of the blind source indicates an area similar to 6 km wide and 33 km long. Multichannel seismic profiles highlight the presence of relevant lateral variations in the structural style of the Ferrara folds that developed during the Pliocene and Pleistocene. There is also evidence of a Mesozoic extensional fault system in the Ferrara arc, with faults that in places have been seismically reactivated. These geological and seismological observations suggest that the 2012 Emilia earthquakes were related to ruptures along blind fault surfaces that are not part of the Pliocene-Pleistocene structural system, but are instead related to a deeper system that is itself closely related to re-activation of a Mesozoic extensional fault system. (C) 2015 Elsevier B.V. All rights reserved.

Palynological studies are considered as an excellent tool for palaeoaltitude estimates as sedimentary basins receive abundant pollen grains from surrounding uplands, especially through riverine detritic inputs. Here, we provide new evidence for estimating the palaeoaltitude of the Northern and Central Apennines (Italy) during the late Neogene (from the late Tortonian to the early Zandean), based on vegetation data derived from pollen analysis of five sections (Trave, Legnagnone, Cava Li Monti, Maccarone and Stirone). The past vegetation changes reflect shifts in the vegetation belts on the nearby massifs. The climate reconstruction realised on these sites, at sea-level, suggests that mean annual temperatures were higher than today at the end of the Neogene. Therefore, the different vegetation belts occurred at higher elevation than at present to compensate for the higher temperatures. The results obtained in our study suggest that the Northern and Central Apennines were uplifted as early as the Tortonian attaining significant minimum altitudes around 1350 m up to 1500 m at the end of the Miocene in the Central part, a minimum altitude around 1900 m during the Messinian and around 2150 m during the early Zandean in the Northern part. (C) 2014 Elsevier B.V. All rights reserved.

Rapporto intermedio. ACCORDO OPERATIVO 2016 tra Consiglio Nazionale delle Ricerche - Istituto di Scienze Marine (ISMAR CNR) e Ministero dello Sviluppo Economico, Direzione Generale per la Sicurezza anche ambientale delle attivit? minerarie ed energetiche - Ufficio Nazionale Minerario per gli Idrocarburi e le Georisorse (DGS-UNMIG).

Geophysical studies point to a complex tectonic and geodynamic evolution of the Alboran Basin and Gulf of Cadiz. Tomographic images show strong seismic waves velocity contrasts in the upper mantle. The high velocity anomaly beneath the Alboran Sea recovered by a number of studies is now a well established feature. Several geodynamic reconstructions have been proposed also on the base of these images. We present and elaborate on results coming from a recent tomography study which concentrates on both the Alboran and the adjacent Atlantic region. These new results, while they confirm the existence of the fast anomaly below the Alboran region, also show interesting features of the lithosphere-asthenosphere system below the Atlantic. A high velocity body is imaged roughly below the Horseshoe Abyssal plain down to sub-lithospheric depths. This feature suggests either a possible initiation or relic subduction. Pronounced low velocity anomalies pervade the upper mantle below the Atlantic region and separate the lithospheres of the two regions. We also notice a strong change of the upper mantle velocity structure going from south to north across the Gorringe Bank. This variation in structure could be related to the different evolution in the opening of the central and northern Atlantic oceans.

Along the similar to 500 km long Sicily-Calabria segment of the Nubia-Eurasia plate boundary GPS data highlight a complex, and debated, kinematic pattern. We focus on eastern Sicily, where the style of crustal deformation rapidly changes in the space of few tens of kilometers. In southeastern Sicily, struck by the 1693 M-W similar to 7.4 earthquake, GPS measurements highlight a steep velocity gradient, with similar to 2.4 mm/yr of similar to N-S shortening in similar to 10 km, changing to broader extension (similar to 3 mm/yr in similar to 60 km) in northern Sicily and shortening in the southern Tyrrhenian Sea. GPS data and kinematic elastic block models highlight a complex fragmentation of the Sicilian domain into three tectonic blocks, which move independently from Nubia, describing an overall clockwise rotation of this crustal domain with respect to Eurasia. Shortening in southeastern Sicily is associated with a system of high-angle reverse faults resulting from tectonic inversion of extensional faults at the northern tip of the Hyblean plateau. Extension in northern Sicily occurs on a broader deformation belt, developed on the former Kumeta-Alcantara line, extending west of Mount Etna toward the southwestern Tyrrhenian Sea, accommodating the faster rotation of the northeastern Sicily block with respect to central Sicily. Although the seismic potential of inland faults is not negligible, our results strengthen the hypothesis that the Malta escarpment is the likely source of the large 1693 earthquake and tsunami. The observed kinematics appears only subordinately driven by the Nubia-Eurasia convergence and the dynamics of the Mediterranean subduction system is likely playing a major role in governing block motions and active tectonics in Sicily. (C) 2014 Elsevier B.V. All rights reserved.

In the westernmost Ionian Sea lies a steep, tectonically active marine basin influenced by turbidity currents generated by terrigenous river input from the adjacent mountains and strong tidal currents propagating through the Strait of Messina. Like many young marine rifts, the basin is lined by steep streams draining the uplifting coasts and supplying sediment across narrow shelves. However, unlike many rifts, this basin is semi-enclosed. The present study explores the seabed morphology and sediment structures in this complex environmental setting, based on multibeam sonar, chirp profiler and seismic reflection data collected in 2006. Offshore channels include many that can be directly linked to onshore streams, suggesting that hyperpycnal flows are important for their formation. Near the Strait of Messina in depths shallower than 400 m, the channels are subdued, plausibly explained as an effect of strong tidal currents. The Messina Channel is characterised by abundant mass-wasting features along its outer bends, particularly on the Calabrian side. Coincidence of the channel course with faults suggests that the channel is structurally controlled in places. The chirp profiles generally show only shallow penetration, the evidence for coarse texture being consistent with the steep gradient of the basin that inhibits deposition from turbidity currents. By contrast, some locally discontinuous mounds exhibiting layered sub-bottom reflectors in the chirp profiles are interpreted as modern levee deposits formed from channelised turbidity current overspill. Overall, this semi-enclosed basin shows little evidence of substantial accumulations associated with modern turbidity current activity, any contemporaneous sediment supply evidently bypassing the area to be deposited in the Ionian Trench; as a consequence, this trench should be an archive of local slope failure and flood events.

The front of the W-verging Albanide fold-and-thrust belt and its adjacent foreland have been investigated using a grid of seismic reflection profiles, purposely acquired in the Southern Adriatic Sea. This convergent margin is part of the continental collision that extends from former Yugoslavia to North-Western Greece. At the front of the Albanides, both the structural style of the external part of the fold-and-thrust belt, and the evolution of the related foredeep basin, are strongly controlled by the nature of the Mesozoic units that are progressively accreted to the belt, namely the Apulian Platform and its adjacent deep-water basins. Where a thick carbonate platform is accreted (souther Albania) the frontal mountain range presents a high topography, whereas the foredeep basin is relatively shallow. On the other hand, where the basinal domain is accreted (northern Albania), the topography of the fold-and-thrust belt is subdue, whereas the foredeep basin is very deep.

Several lines of geophysical evidence suggest that the slab subducted underneath the Tyrrhenian sea is made up of oceanic lithosphere. This requires that an oceanic domain was present to the west of the Apulian Platform during the Mesozoic. The sediments of the Lagonegro basin were likely deposited within this oceanic domain, and related continental palaeomargin. The sinking and rolling back of the dense Ionian oceanic lithosphere controlled, to a large extent, the Neogene geological evolution of the Southern Apennines - Tyrrhenian system. In fact, most of the evolution of the Southern Apennines can be accounted for by an accretionary wedge tectonic. Only in the final stages, from Late Miocene-Early Pliocene, the accretionary wedge docked on the continental margin and was emplaced on the Apulian Platform, originating the present structural stack of the southern Apennines. It is here proposed that the Apennine Platform had an original intraoceanic position and was successively incorporated within the accretionary wedge, being detached from its infra-Triassic substratum.

Despite the clear evidence of active flank dynamics that is affecting the eastern side of Mount Etna, the contribution of tectonic processes has not been yet understood. So far, the various models proposed to explain the observed flank deformation have been based on onshore structural data, coming from the volcanic edifice. The Ionian offshore of Mount Etna has been only recently investigated using multichannel seismic profiles, and offers the opportunity to image the structural features of the substrate of the unstable flank of the volcano. This contribution aims at describing the deformation located offshore Mount Etna using multichannel seismic profiles recently acquired during three seismic surveys. The onshore flank deformation of Mount Etna appears to be laterally confined by two tectonic guidelines, trending roughly E–W, located to the north and south of the deforming flank; the northern guideline, in particular, takes the surface expression of a sharp fault (Pernicana Fault). Though often assumed that these boundary structures continue offshore as linear features, connected to a frontal thrust ramp, the occurrence of this simple offshore structural system has not been imaged. In fact, seismic data show a remarkable degree of structural complexity offshore Mount Etna. The Pernicana Fault, for instance, is not continuing offshore as a sharp feature; rather, the deformation is expressed as ENE–WSW folds located very close to the coastline. It is possible that these tectonic structures might have affected the offshore of Mount Etna before the Pernicana Fault system was developed, less than 15 ka ago. The southern guideline of the collapsing eastern flank of the volcano is poorly expressed onshore, and does not show up offshore; in fact, seismic data indicate that the Catania canyon, a remarkable E–W-trending feature, does not reflect a tectonic control. Seismic interpretation also shows the occurrence of a structural high located just offshore the edifice of Mount Etna. Whereas a complex deformation affects the boundary of this offshore bulge, it shows only limited internal deformation. Part of the topography of the offshore bulge pre-existed the constructional phase of Mount Etna, being an extension of the Hyblean Plateau. Only in the northern part, the bulge is a recent tectonic feature, being composed by Plio-Quaternary strata that were folded before and during the building of Mount Etna. The offshore bulge is bounded by a thrust fault that can be related to the intrusion of the large-scale magmatic body below Mount Etna.

Sediment supplied by continental sources is commonly suspected to have exerted a strong influence on the development of canyons and other morphological features on the continental slopes, but rarely is the sediment supply known sufficiently quantitatively to test this link. Here, we outline an area where offshore morphology, in the western Ionian Sea, may be linked to estimated sediment fluxes produced by subaerial erosion in NE Sicily and SW Calabria. Shelves in this area are narrow (

The polarity of subduction in the Corsica–Northern Apennine system is a long-debated issue. Models adopting an original W-dipping subduction and models preferring a flip in the polarity of subduction, from E-dipping to W-dipping present inconsistencies that are mainly due to the 2D approach. A new proposal is presented, using Late Cretaceous to Present-Day kinematic reconstructions of the Central Mediterranean. A wide oceanic embayment is required to the west of the Adriatic Promontory, to account for the Oligocene-Present calcalkaline volcanism and back‐arc extension. This implies that the continental collision that originated the Alps s.s. could not continue SW-ward of Adria. The change in subduction polarity, going from the Alps, to the Apennines, is taken as on original feature since the beginning of convergence. Kinematic reconstructions show that the point where subduction polarity changes moved N-ward along the plate boundary, from Late Cretaceous to Eocene. As a result, areas that previously experienced the continental collision of the Adriatic Promontory were subsequently affected by the oceanic subduction of the Tethyan embayment. This sequence of events caused the collapse of Alpine Corsica and led to the opening of the Balearic back‐arc basin. A similar kinematic evolution is ongoing in Taiwan, where the N-ward subduction of the Philippine Sea plate is progressively substituting the E-ward subduction of the Eurasian plate, causing the collapse of the orogen in northern Taiwan. The slivers of continental basement rocks that are encased within the uppermost nappe in Corsica have been interpreted as remnants of a microplate that collided with Corsica. Plate kinematics offers an alternative explanation, with these basement rocks being derived from the colliding Adriatic promontory during Paleocene–Eocene; the promontory then passed away laterally, allowing the juxtaposition of the Alpine belt of Corsica with the early Apennines.

The Straits of Messina and its surroundings are considered as one of the most tectonically active area of the Mediterranean, but in spite of their hazard potential, modern geophysical data aimed at investigating their hidden structures are lacking. In order to bridge this gap, we carried out a marine multichannel seismic survey primarily aimed at: i) studying the regional fault pattern in the area of the Messina 1908 earthquake; and ii) checking the existence of a potentially seismogenic fault, the Taormina Fault, which many authors locate offshore, along the coast between Taormina and Messina. Our seismic profiles show a great structural complexity within the Messina Straits, with the best imaged faults occurring on the Calabrian side. In particular, a more than 30 km long NW-trending fault located at the SW tip of Calabria is cutting the sea floor. Moreover, our data did not image any extensional fault plane attributable to the Taormina Fault; rather, the whole slope has been tilted east-ward. The geodynamic implication is that extension in south-eastern Sicily, on the Ionian side of the Hyblean Plateau, and extension in southern Calabria and Messina Straits belong to two different tectonic systems and cannot be mechanically linked.

A new proposal attempting to solve the long-debated issue of the polarity of subduction in the Corsica-Northern Apennine system is presented. Models adopting an original W-dipping subduction and models preferring a flip in the polariy of subduction, from E-dipping to W-dipping, encounter major difficulties at a regional scale. It is considered here that the main inconsistencies faced by both models are due to the two-dimensional approach of reconstructions. The Late Cretaceous to Present-Day kinematics of the Central Mediterranean has been reconstructed using the magnetic anomalies in the Atlantic Ocean and assuming a solid connection between Africa and Adria. Oligocene to Present calcalkaline volcanism and backarc extension in the Balearic and Tyrrhenian basins requires the presence of a wide oceanic embayment to the west of the Adriatic Promontory. It follows that the continental collision that gave rise to the Alps s.s. could not continue SW-ward of Adria. The flip of subduction polarity that can be currently observed, going from the Alps, where Africa is overriding Europe, to the Apennines, where the opposite occurs, was likely on original feature since the beginning of convergence. Kinematic reconstructions allow the point along the plate boundary where the flip of polarity occurs to be tracked back in time. Following the N-ward motion of the colliding Adriatic Promontory, the point of polarity flip moved along the plate boundary from Late Cretaceous to Eocene. As a result, areas that previously experienced continental collision were subsequently affected by oceanic subduction. This sequence of events led to the collapse of the Alpine belt of Corsica and to the opening of the Balearic backarc basin above a retreating oceanic subduction. A similar kinematic evolution is currently ongoing in Taiwan. Finally, the Northern Tyrrhenian basin opened when delamination affected the Adriatic continental margin, following the consumption of oceanic lithosphere at the end of Corsica-Sardinia rotation.

The evolution of the southern Tyrrhenian subduction has been possibly controlled by distinct episodes of slab break-off as indicated by a critical review of the geological literature and by the analysis of purposely acquired multichannel seismic profiles. Within the proposed interpretation the first episode occurred from 8.5 to 4.0 Ma and affected the segment of the slab located in the Sardinia Channel, causing the abandonment of the Adventure thrust front in western Sicily. The second episode occurred between 2.5 and 1.6 Ma, affecting the segment of slab located north of Sicily, and was preceeded by rifting in the Strait of Sicily. The space and time location of these episodes appear controlled by discontinuities pre-existing within the subducted African plate that trend at high angle to the advancing subduction front. These discontinuities delimit segment of subducted slab that can be affected by slab break-off and can act as wayouts for magma and mantle derived He. The major of these discontinuities, the Malta Escarpment, has been reactivated in the Quaternary as a trench-perpendicular tear (STEP faults). Ultimately, the hierarchy in strength of these trench-perpendicular features could have affected the timing and amount of trench retreat and backarc opening.

The deep seismicity and lateral distribution of seismic velocity in the Central Western Mediterranean, point to the existence under the Alboran and Tyrrhenian Seas of two lithospheric slabs reaching the mantle transition zone. Gibraltar and Calabrian narrow arcs correspond to the slabs. Similarities in the tectonic and mantle structure of the two areas have been explained by a common subduction and roll-back mechanism, in which the two arcs are symmetrical end members. We present a new 3-D tomographic model at mantle scale for the Calabrian Arc and compare it with a recently published model for the Gibraltar Arc by Monna et al. ( 2013a ). The two models, calculated with inversion of teleseismic phase arrivals, have a scale and parametrization that allow for a direct comparison. The inclusion in both inversions of ocean bottom seismometer broadband data improves the resolution of the areas underlying the seafloor networks. This additional information is used to resolve the deep structure and constrain the reconstruction of the Central Western Mediterranean geodynamic evolution. The Gibraltar tomography model suggests that the slab is separated from the Atlantic oceanic domain by a portion of African continental margin, whereas the Calabrian model displays a continuous oceanic slab that is connected, via a narrow passage (~ 350 km), to the Ionian basin oceanic domain. Starting from the comparison of the two models we propose the following interpretation: within the Mediterranean geodynamic regime (dominated by slab rollback) the geometry of the African continental margin, located on the lower plate, represents a critical control on the evolution of subduction. As buoyant continental lithosphere entered the subduction zones, slab pull caused tears in the subducted lithosphere. This tectonic response, which occurred in the final stages of arc evolution and was strongly controlled by the paleogeography of the subducted plates, explains the observed differences between the Gibraltar and Calabrian Arcs.

In their comments Bonini et al. argue that our seismotectonic interpretation of the Emilia 2012 seismic sequence does not agree with observations, and follow three lines of arguments to support their statement. These concern the structural interpretation of seismic reflection profiles, the relationship between seismogenic sources and seismicity patterns, and the fit of inferred fault geometry to InSAR observations. These lines of arguments are mostly repeating what has been previously presented by the same authors, and none of them, as discussed in detail in our reply, presents a strong case against our structural interpretation, that, we are convinced, does not conflict with the available data. The two adjacent rupture surfaces outlined by accurately relocated aftershocks are an indication of the presence of two different active fault planes. Interpretation of seismic profiles supports seismological observation and indicates the occurrence of relevant along-strike changes in structural style. These pieces of information have been integrated to build a new seismotectonic interpretation for the area of the Emilia 2012 seismic sequence. Analysis of geodetic data from the area of the Emilia earthquakes has produced very different models of the fault planes; unlike what has been stated by Bonini et al., who see a difficult fit to InSAR data for the fault planes we have identified, the most recent results are consistent with our interpretation that see a steep fault in the upper 8–10 km under the Mirandola anticline. We point out that the geological structures in the subsurface of the Ferrara Arc do change along strike, and the attempt of Bonini et al. to explain both the May 20 and May 29 sequences using a single cross section is not appropriate.

The Upper Cretaceous Helminthoid Flysch (HF) of the Northern Apennines consists of thick and regionally widespread deep-water carbonate turbidite successions, deposited during the initial stages of Alpine collision. The HF spans the time from Turonian to Early Eocene and is mainly composed of intrabasinal carbonate ooze mixed with clay; siliciclastic terrigenous beds are also present, but they are a volumetrically minor component of the successions. Petrographic and sedimentological signatures indicate that the HF was deposited in distinct basins located below the carbonate compensation depth. Bulk composition and heavy minerals of terrigenous beds indicate provenance from different crustal levels of the European and Adria plates. The petrographic and palaeobathymetric characteristics of these turbidites indicate the coexistence of an active-margin tectonic setting, a palaeogeographical position suitable for carbonate ooze production and storage, and limited supply of terrigenous detritus into the basin. Palaeotectonic reconstructions and stratigraphic data suggest that Adria represented a vast repository of penecontemporaneous carbonate mud; the presumably intense seismic activity related to the pre-collisional Alpine orogeny promoted large-scale failures of shelf and/or slope biogenic muddy sediments, resulting in the deposition of a large volume of carbonate turbidites. Only occasionally, turbidity currents probably linked to exceptional fluvial floods generated pure terrigenous beds with different petrographic signatures for each HF succession. The oceanic crust of the Tethyan domain and its overlying sediments have been extensively involved in the long-lasting subduction processes that ultimately led to the Eocene continental collision in the Alps (Coward & Dietrich 1989). Large volumes of carbonate turbidites, known in the Apennines as Helminthoid Flysch (HF), were deposited within deep-sea trenches and on the remnant ocean basin floor (Abbate & Sagri 1970; Argnani et al. 2004) during the period preceding collision between Africa and Europe (Dewey et al. 1973, 1989). Sedimentary successions comparable with the HF crop out in a fairly continuous belt along the Alpine system, from the Northern Apennines to the Eastern Alps (Fig. 1a; Rowan, 1990) and span the time from Turonian to Early

The neotectonics of the Northern Apennines is illustrated using a crustal-scale geoseismic cross-section, based on seismic profiles and field mapping. The geological profile crosses a variety of tectonic settings, from the Val di Vara and Val Magra (VV–VM) grabens in the inner side of the Apennines, to the pede-Apennine thrust fronts (PTF), and finally to the external fronts of the Apennines. Both the VV–VM extensional system and the PTF show evidence of Early Pleistocene tectonic activity, whereas thrusting in the external Apennine ended by Late Pliocene. The sole decollement of the external thrusts cuts down westwards into the basement to a depth of about 15 km, whereas the PTF joins a shallower detachment surface that follows the top of the basement. This basal surface also represents the basal detachment of the VV–VM extensional system, with the VV–VM and PTF defining a large-scale gravitational spreading system. We hypothesise that the regional Quaternary uplift that affected the internal sector of the Apennines promoted a gravitational spreading in the upper part of the orogenic wedge, accounting for the coeval extension in the VV–VM and shortening at the PTF, and applicable to a 100 km long sector of the Northern Apennines.

We built a 3D seismic model of the Po Plain and neighboring regions of northern Italy, covering altogether an area about 600 km by 300 km with an approximately 1 km spaced grid. We started by collecting an extensive and diverse set of geological and geophysical data, including seismic reflection and refraction profiles, borehole logs, and available geological information. Major geological boundaries and discontinuities have thus been identified and mapped into the model. We used kriging to interpolate the geographically sparse information into continuous surfaces delimiting geological bodies with laterally varying thickness. Seismic‐wave properties have been assigned to each unit using a rule‐based system and, V P , V S , and ρ derived from other studies. Sedimentary strata, although with varying levels of compaction and hence material properties, may locally reach a thickness of 15 km and give rise to significant effects in seismic‐wave propagation. We have used our new model to compute the seismic response for two recent earthquakes, to test its performance. Results show that the 3D model reproduces the large amplitude and the long duration of shaking seen in the observed waveforms recorded on sediments, whereas paths outside the basin may be well fit by more homogeneous (1D) hard rock structure. We conclude that the new model is suited for simulation of wave propagation, mostly for T >3 s, and may serve well as a constraint for earthquake location and further improvements via body‐ or surface‐wave inversion.

Paleomagnetic analysis was carried out in the northern Apennines on Eocene to Pliocene Epiligurian units. Five Early Miocene and two Middle Miocene sites yielded dual polarity site-mean directions which show signs of clustering after correction for bedding tilt. These likely primary magnetizations, in conjunction with data from the literature, give an overall mean Late Oligocene–Middle Miocene paleomagnetic pole which shows a large and significant counterclockwise rotation of 52° (±≈8°) with respect to the Africa reference paleopoles (or a similar amount of rotation with respect to the coeval Europe reference paleopole). However, this paleopole falls close to the roughly coeval paleopole for Corsica–Sardinia, which is here calculated by averaging data from the literature. Three additional Early Miocene sites from an area west of Parma affected by Pliocene tectonics yielded site-mean directions which pass the fold test and are rotated counterclockwise by a lesser amount than the rest of the Miocene sites. Most of the remaining sites bear paleomagnetic directions acquired after tilting during a recent phase of remagnetization. We suggest that the large-scale rotation observed in the northern Apennines was associated with the motion of the Corsica–Sardinia block within the general context of the Africa–Europe relative motions. A compilation of published data from the central Apennines also shows a differential rotation of the northern relative to the southern Umbria belt which occurred after the motion of Corsica–Sardinia and may have been due to pivoting of the northern Umbria belt against a deep-seated lineament during the non-rotational opening of the Tyrrhenian Sea.

The oceanic lithosphere of the Ionian Sea is subducted under the Calabrian Arc, and it has been proposed that the Ionian lithosphere has been torn apart (STEP fault sensu Govers and Wortel, 2005) on its western side, close to the Malta escarpment, a major morphological feature inherited from the Mesozoic palaeogeography. In a recent paper Gallais et al. (Tectonophysics, 2013) have traced a right-lateral strike-slip fault that extends from south of the Alfeo Seamount all the way to the Tyrrhenian Sea. They also argue that the position of the STEP fault is distinct from, and located ca. 50 km east of, the Malta escarpment. Gallais et al. document with some additional details a fault segment that was already reported in the literature and that is located south of the Alfeo Seamount. However, Gallais et al. have little constraints to trace the STEP fault further to the north; in this sector a belt of surface deformation that can be related to the STEP fault has been mapped from a denser grid of seismic profiles, and is located west-ward, close to the Malta escarpment (Argnani and Bonazzi, 2005). This undermines the conclusion of Gallais et al. that the lithospheric tear is distinct from the Malta escarpment. It is therefore likely that surface deformation associated with the lithospheric tear fault is more complex and is not represented by a single strike-slip fault.

Extensional basins are known to occur on top of the Apennine Maghrebian fold-and-thrust belt that runs along Sicily and peninsular Italy. They formed mainly during the Plio-Quaternary, presumably in relation to the opening of the Tyrrhenian back-arc basin, while contraction was active at the thrust front. Contractional structures are often present within their sedimentary infill. One of these basins, INVO-2 located southwest of the Egadi islands, has been investigated using a closely spaced grid of multichannel seismic reflection profiles in order to define its structural style. Basin INVO-2 was formed along a system of NW-SE-trending extensional faults and is subdivided into two subbasins separated by a morphologic high. Flipping of half-graben polarity is often encountered along the axis of the two subbasins. Contractional structures, trending both perpendicular and parallel to the basin axis, occur within the basin infill, and in some instances these structures can be related to reactivation of previous extensional faults. Although the lack of well control does not allow a precise dating of the contractional episodes, they appear to occur intermittently, from the onset of the basin until recent times, intercalated to a dominant extensional regime. The origin of compressional pulses in this extensional setting can be looked for in the dynamics of the adjacent Maghrebian collision zone.

The general modular Bayesian procedure is applied to provide a probabilistic tsunami hazard assessment (PTHA) for the Messina Strait Area (MSA), Italy. This is the first study in an Italian area where the potential tsunamigenic events caused by both submarine seismic sources (SSSs) and submarine mass failures (SMFs) are examined in a probabilistic assessment. The SSSs are localized on active faults in MSA as indicated by the instrumental data of the catalogue of the Italian seismicity; the SMFs are spatially identified using their propensity to failure in the Ionian and Tyrrhenian Seas on the basis of mean slope and mean depth, and using marine geology background knowledge. In both cases the associated probability of occurrence is provided. The run-ups were calculated at key sites that are main cities and/or important sites along the Eastern Sicily and the Southern Calabria coasts where tsunami events were recorded in the past. The posterior probability distribution combines the prior probability and the likelihood calculated in the MSA. The prior probability is based on the physical model of the tsunami process, and the likelihood is based on the historical data collected by the historical catalogues, background knowledge, and marine geological information. The posterior SSSs and SMFs tsunami probabilities are comparable and are combined to produce a final probability for a full PTHA in MSA. © 2012 Springer Science+Business Media B.V.

Geophysical and geological marine data recently collected allow to outline the structure of the basement-involved fold-thrust belt, developed during the Late Cenozoic between Sardinia and Tunisia, along the Africa-Europe plate boundary. By integrating these with inland data, it is possible to document, step by step, the progression of crustal thickening from north to south, and the collapse of the first uplifted northern units, while collision was still going on. The geodynamic setting suggests that coupled extensional collapse and fold-thrust propagation were driven by island arc drifting above a southward-retreating subduction zone.

The southern Adriatic basin is the current foredeep of the Albanide fold-and-thrust belt that runs along the eastern boundary of the Adriatic basin and partly owes its remarkable water depth, deeper than 1,000 m, to the Mesozoic palaeogeography of the region. The eastern slope of the southern Adriatic basin is characterized by a thick stack of sedimentary prograding units, fed by sediments coming from the adjacent fold-and-thrust belt, which is still seismically active (e. g. 1979 Montenegro, M = 6. 8). This slope presents extensive evidence of large-scale mass wasting throughout its Quaternary evolution and appears as a destructive slope system affected by progressive retreat. A submarine slide located along the eastern slope of the southern Adriatic basin has been recently characterized with good detail. The slide is of relatively small volume (0. 031 km3) and shows a limited displacement, without major internal disruption. The small volume of the landslide combined with its relatively large water depth (headscarp at about 560 m and deposit at 700 m) result in a limited tsunamigenic potential, that has been assessed numerically by means of a Lagrangian block model as regards the slide motion and through a shallow-water finite-difference code for the tsunami waves propagation. Despite the almost negligible tsunami effects, the studied landslide can be taken as a lower case limit for other events along the scarp, and the observed features concerning the generated wave and its impact on the coast can be considered valid also for bigger events.

[1] The December 28th 1908 Messina Earthquake has been ranked as one of the most destructive events of the last centuries [Davison, 1936] The damages produced by ground shaking were aggravated by the effects of a remarkable tsunami, with up to 11 m of run-up height, that followed the earthquake [Omori, 1909; Baratta, 1910; Tinti et al., 2004]. The location of the causative fault is still a matter of debate [e.g., Argnani et al., 2009], the modelling of the associated tsunami [Tinti and Armigliato, 2003] allowing uncertainty. [2] Billi et al. [2008] have recently proposed that the tsunami that stroke the coast of the Strait in December 1908 originated from a large submarine landslide (20 km) located offshoreGiardini-Naxos. The hypothesis is based on the study of tsunami arrival times [Platania, 1909; Baratta, 1910] and is supported, according to Billi et al. [2008], by inspection of: a multibeam morphobathymetry [Marani et al., 2004] and of a crustal-scale seismic profile [Scrocca et al., 2004]. [3] The arguments of Billi et al. [2008], however, have weak points that cast doubt on their interpretation. But most importantly, data collected in the last few years by the authors of this comment (A. Argnani and F. Chiocci), and work on tsunami modelling (S. Tinti and his group) cast further doubt on the proposed hypothesis that a large submarine landslide that was caused by the 1908 earthquake is located offshore Giardini-Naxos. These issues will be discussed in the following.

A reappraisal of the seismic profiles available over the Strait of Sicily rift zone has been undertaken in order to unravel its tectonic evolution. Although the area presents great structural complexity, the motion along the basin-boundary faults appears to have been mostly dip-slip with extension directed roughly NE-SW. A wide N-S trending belt characterized by localized uplifts and depocentres, alkaline volcanics and structural inversions, separates the Pantelleria Trough to the west from the Malta and Linosa troughs to the east. This belt presents evidence of strike-slip tectonics and acted as a transfer fault zone between two segments of the rift system. The rifting occurred mostly during the Pliocene and was followed by a post-rift phase, with no sign of extension within the troughs, that probably spanned the whole Quaternary. Only within the Pantelleria Trough has a recent contractional episode been observed. The origin of the rift system is hypothetically related to the opening of the Tyrrhenian back-arc basin which occurred at the same time. Roll-back of the subducted slab and lithospheric mantle delamination have been proposed as feasible mechanisms originating the Tyrrhenian back-arc basin and the coeval contraction in the Apennine-Maghrebian fold-thrust belt. Both these mechanisms can also produce a limited amount of extension in the Strait of Sicily due to slab-pull and secondary mantle convection, respectively.

The 1,500-km2 Gela slide and associated debris flow deposits cover most of the Gela foredeep basin (Sicily channel). The head of the slide follows the tip of the arcuate Gela nappe. A basin-wide detachment surface extends from the extensional slide head to a distal, contractional zone.

SUMMARY The Western Mediterranean displays a complex pattern of crustal deformation distributed along tectonically active belts developed in the framework of slow oblique plate convergence. We used earthquake and Global Positioning System (GPS) data to study the present-day kinematics and tectonics of the Africa-Eurasia plate boundary in this region. Crustal seismicity and focal mechanisms, analysed in terms of seismic moment release and seismic deformation, outline the geometry of major seismic belts and characterize their tectonics and kinematics. Continuous GPS data have been analysed to determine Euler vectors for the Nubian and Eurasian plates and to provide the global frame for a new Mediterranean GPS velocity field, obtained by merging continuous and campaign observations collected in the 1991‐2005 time span. GPS velocities and displacements predicted by the Nubia-Eurasia rotation pole provide estimates of the deformation accommodated across the tectonically active belts. The rather simple deformation occurring in the Atlantic region, characterized by extension about perpendicular to the Middle Atlantic and Terceira ridges and right-lateral motion along the Gloria transform fault, turns into a complex pattern of deformation, occurring along broader seismic belts, where continental lithosphere is involved. Our analysis reveals a more complex fragmentation of the plate boundary than previously proposed. The roughly E-W trending mainly compressive segments (i.e. southwestern Iberia, northern Algeria and southern Tyrrhenian), where plate convergence is largely accomodated across rather localized deformation zones, and partially transferred northward to the adjacent domains (i.e. the Algero-Balearic and Tyrrhenian basins), are interrupted by regions of more distributed deformation (i.e. the Rif-Alboran-Betics, Tunisia-Libya and eastern Sicily) or limited seismicity (i.e. the Strait of Sicily), which are characterized by less homogeneous tectonics regimes (mainly transcurrent to extensional). In correspondence of the observed breaks, tectonic structures with different orientation interfere, and we find belts with only limited deformation (i.e. the High and Middle Atlas, the Tunisian Atlas and the offshore Tunisia-Libya belt) that extends from the plate boundary into the Nubian plate, along pre-existing tectonic lineaments. Our analysis suggest that the Sicilian-Pelagian domain is moving independently from Nubia, according to the presence of a right-lateral and extensional decoupling zone corresponding to the Tunisia-Libya and Strait of Sicily deformation zone. Despite the space variability of active tectonic regimes, plate convergence still governs most of the seismotectonic and kinematic setting up to the central Aeolian region. In general, local complexities derive from pre-existing structural features, inherited from the tectonic evolution of the Mediterranean region. On the contrary, along Calabria and the Apennines the contribution of the subducted Ionian oceanic lithosphere and the occurrence of microplates (i.e. Adria) appear to substantially modify both tectonics and kinematics. Finally, GPS data across the Gibraltar Arc and the Tyrrhenian-Calabria domain support the hypothesis that slab rollback in these regions is mostly slowed down or stopped.

The tectonics of the central Aeolian Islands, which are located within the Tyrrhenian backarc basin, has been investigated through a marine seismic reflection survey. We find that compressional structures dominate around the islands, whereas extensional faults occur only to the north of Salina and Filicudi, towards the Marsili basin. This pattern of deformation, although different from previously reported, is in agreement with the strain field and stress regime obtained from GPS measurements and seismological data. Age constraints suggest that contractional deformation was active since middle Pleistocene, being coeval with the building of the volcanic edifices of the Aeolian Islands, and is superimposed on pre-existing extensional deformation. Compressional and extensional regimes, therefore, can coexist within a backarc setting. Seismic profiles show that the Tindari-Letojanni fault, considered as a major tectonic element, does not extend to the north towards the island of Vulcano as a throughgoing fault; rather, deformation is accommodated in a broader belt displaying greater structural complexity.

[1] The Malta Escarpment represents the dominant morphological feature offshore eastern Sicily, linking the deep Ionian basin to the east with the Hyblean carbonate platform to the west. Interpretation of purposely acquired multichannel seismic data allows division of the Malta Escarpment into two portions characterized by different tectonic structures. Along the segment south of Siracusa the Malta Escarpment is not affected by recent faulting and appears as a steep surface that flattens out toward the Ionian basin. A recent deformation, characterized by a broad area of uplift, occurs 20–30 km east from the slope, along a NNW-SSE trend. The segment of the Malta Escarpment extending north of Siracusa, on the other hand, is characterized by the presence of NNW-SSE, east dipping recent extensional faults and related sedimentary basins. The observed structural features support the occurrence of a lithospheric tear between the Ionian oceanic basin and the Hyblean plateau.