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The Sicily dominates the central Mediterranean Sea. The Northern Sicily Continental Margin (NSCM) is a segment of the Appeninic-Tyrrhenian System whose upbuilding refers to both the postcollisional convergence between Africa and a very complex “European” crust (Bonardi et al., 2001) or AlKaPeKa (sensu Boullin, 1986) and the opening of the Tyrrhenian back-arc basin. Seismostratigraphic and structural analysis of a large number of available (from ViDePi project) and unpublished (from Department of Earth and Marine Science of the University of Palermo) multichannel seismic reflection profiles acquired across the NSCM, allow us to produce an accurate seismotectonic map, in order to obtain a useful tool for the assessment of the seismic hazard of the sea-land region. This first seismotectonic map has been realised from the overlapping of different geological layers that represent the main identified seafloor and sub-seafloor features, such as tectonic elements (normal and revers faults), earthquakes, heat flow, gravimetric (Bouguer) and magnetometric anomalies, Moho depth, masswasting, fluid escape structures (e.g. pockmarks, mounds, gas flares, and gas chimneys), sedimentary successions, and lateral and vertical motions. The NSCM is suitable to test this approach because it is located in a transitional area between the Sicilian-Maghrebian chain to the south and the Tyrrhenian back-arc basin to the north. Along this transect the Moho depth ranges from about 10 km, in the Marsili bathyal plain, to about 40 km, towards the northern Sicily coast. The Bouguer anomalies change from 180 mGal in the Tyrrhenian region to negative anomalies in central Sicily (-100 mGal), while positive magnetic anomalies characterize the volcanic edifices, both submerged and buried. While, the heat flow shows very high values across the southern Tyrrhenian Sea (200 mW/m-2) that decrease (30- 40 mW/m-2) towards the stable sector of the foreland area (Iblean plateau in SE Sicily). Along the NSCM, we distinguished, at a regional scale, different shallow and deep seismogenetic volumes. The eastern part of the Sicilian continental margin is characterised by a deeper seismicity related to the Ionian subduction, which is prevailingly linked both to extensional fault systems (Pollina, Messina strait) and to rightlateral NW-SE transcurrent systems (Vulcano- Lipari and Tindari-Giardini). While the western region shows shallow earthquakes (up to 25 km) of low to moderate magnitude (max Mw 5.9 on September 2002) occurring along an E-W trending belt and resulting from the brittle deformation of the Maghrebian chain. The focal mechanisms related to the main seismic shocks are in agreement with a dominant NW-SE compressive offset direction, with a right strike-slip component, and an antithetic NE-SW fault trend. Evidences of mass-wasting processes have been identified across the continental shelf and the continental slope and their spatial distribution, geometry, and seismic character suggest that the fluid seepage, oceanographic processes and the slope oversteepening could be important preconditioning factors, while the tectonic activity showing fault displacements during earthquakes is the main trigger. During the last 125 ky tectonic activity is evidenced by an uplift/subsidence patterns, decreasing from E to W. The continental regions are raised while offshore areas are subsiding, suggesting the occurrence of vertical differential movements. The GPS measurements document the active deformation with differential movements of individual blocks northwarddirected, in agreement with the shallow seismicity, as well as with the convergence between Sicily and Sardinia, with values of about 2-6 mm/y. The first step of this work produced the detailed seismotectonic map between the Castellammare and Palermo gulfs, including both the terrestrial and marine areas. Across the NSCM, we defined two main seismogenetic volumes that are produced by a NW-SE oriented compressional stress field defining an intraplate shallow seismogenetic zone. Though these results are only preliminary, we are developing a scientific product that can provide useful information in terms of seismic hazard in a complex region that includes both continental and marine sectors. Therefore, the identified geological features may be potentially geohazard elements for the neighbouring population and for the near goods, as well as submarine infrastructures (i.e. cables) and our seismotectonic map represent an important tool for monitoring the potentially seismogenic structures and assessing geohazards in marine and coastal environments.

An integrated analysis approach, based on geological investigations and 2D high-resolution shallow geophysical data, was proposed along a slope in the Bellolampo landfill area (Palermo, Italy) where the presence of a fault zone was hypothesized. Geophysical surveys included electrical resistivity tomography (ERT), induced polarization tomography (IPT) and seismic refraction tomography (SRT) techniques. The inversion of single geophysical parameter often does not allow to justify the complexity of the subsoil structures. The most appropriate solution should be to add additional physical or geological information so to get a constrained geological model. However, it is not at all easy to work with multivariate datasets due to the lack of well-defined relationships between different parameters. A solution can be a joint inversion procedure with mathematical constraints that favoured final models providing similar spatial distribution of the discontinuities (Gallardo and Meju 2007; 2011). In addition, the use of post-inversion techniques of independent univariate models can help to understand the relationships between different observable parameters (Bedrosian et al. 2007; Dell'Aversana 2001; Di Giuseppe et al. 2014). In particular, these techniques have shown excellent results when applied to seismic and electrical tomography data (Bohm et al. 2017; Capizzi et al. 2017; Gallardo and Meju 2003; 2004).

Active processes in the Northern Sicily Continental Margin (NSCM) have been analysed to produce a seismotectonic map, in order to obtain a useful tool for the assessment of the seismic hazard of the sea-land region. The seismotectonic map is composed of overlapping layers that represent the distribution of different features, such as lithostratigraphy, tectonic elements, seismicity, heat flow, gravimetry, magnetometry, Moho depth, horizontal and vertical movements, submarine landslides, fluid emissions, outlining the mutual relationship and the active structures. The NSCM is suitable to test this approach because it’s located in a transitional area between the Sicilian-Maghrebian chain to the south and the Tyrrhenian back-arc basin to the north. Along this transect the Moho depth ranges from about 10 km, in the Marsili bathyal plain, to about 40 km, towards the northern Sicily coast. The Bouguer anomalies change from 180 mGal in the Tyrrhenian region to negative anomalies in central Sicily (-100 mGal), while positive magnetic anomalies characterize the volcanic edifices, both submerged and buried. The heat flow values are high in the Tyrrhenian Sea (200 mW/m-2), decreasing (30-40 mW/m-2) towards the stable sector of the foreland area (Iblean plateau in SE Sicily). At a regional scale, in the NSCM we distinguished different seismogenetic volumes, both shallow and deep. The deep seismicity, relative to the Ionian subduction, is prevailing in the eastern margin, but the shallow events are the result of the brittle deformation of the Maghrebian chain. In the western sector, shallow hypocentres occur along an E-W belt, with focal mechanisms coherent with a NW-SE compression. To the East seismicity is linked to NW-SE trending extensional to right-lateral transcurrent fault systems. During the last 125 ky tectonic activity is evidenced by vertical movements, decreasing from E to W; moreover, while the continental sectors are raised, offshore areas are subsiding, suggesting the occurrence of vertical differential movements. The GPS values document the active deformation with differential movements of individual blocks northward-directed, in agreement with the shallow seismicity, as well as the convergence between Sicily and Sardinia, with values of about 2-6 mm/y. The first step of this research produced the detailed seismotectonic map between the Castellammare and Palermo gulfs, including both the emerged and marine areas. In this sector we defined two seismogenetic volumes, produced by a NW-SE oriented compressional stress field, and defining an intraplate shallow seismogenetic zone. Though these results are only preliminary, we are developing a scientific product that can provide useful information in terms of seismic hazard in a complex region that includes both continental and marine sectors. Therefore, it could represent an important tool for monitoring the potentially seismogenic structures and assessing geohazards in marine and coastal environments

The Sicilian Fold and Thrust belt (SFTB) is a structurally complex area where along-strike variations of structural styles, shortening amounts, exhumation rates and amounts of syn-tectonic sedimentation frequently occur. Moreover strong differential clockwise rotations around vertical axes affected the different tectonic units during their emplacement. This complexity, coupled with debatable or incomplete subsurface dataset (e.g., available 2D onshore seismic lines) allowed previous authors to propose different interpretations for the tectonic evolution of the SFTB since Cenozoic time. The study area, located in the Western sector of the SFTB comprises the Kumeta and Busambra ridges (derived from the deformation of Mesozoic and Cenozoic shallow water and pelagic carbonate deposits, named Trapanese unit), represents a paradigm of such a structural complexity. The two main structural interpretations available for this area consider the Kumeta and Busambra ridges either as: I) flower structures due to strike-slip tectonics or II) thrust sheets deeply buried by the overthrusting of Mesozoic-Cenozoic deep-water carbonate thin-skinned thrust sheets (named Imerese and Sicanian units), subsequently exhumed by more deeply seated thrusts or transpressive faults. The 3D structural model was reconstructed based on both seismic interpretation and field data. The horizons interpreted are: the top of Cretaceous carbonates and top of Miocene marl deposits of the Trapanese unit, which represent the “autochthonous” unit, and the top of Mesozoic-Cenozoic deep-water carbonates (Sicano, Imerese units) and Oligocene-Miocene foredeep deposits (named Numidian Flysch unit) which represent the allochthonous unit. A detailed structural model was reconstructed only for the autochthonous unit. Along strike variation of structural style was recognized. The main structures reconstructed are: WNW-ESE thrusts in the western sector of the study area; WNW-ESE backthrusts in the eastern sector; NNE-SSW tear faults in the northern sector; WNW-ESE to E-W high angle reverse to transpressive faults along the Kumeta and Busambra ridges. The transpressive movement along high angle faults probably reactivates pre-existing normal faults of the original passive margin. Paleo-thermal data (vitrinite reflectance, Tmax, illite content in mixed layers illite-smectite) and thermal modelling indicate levels of thermal maturity higher in the Imerese unit than the Trapanese unit. Low burial amounts (0.8 - 1.2 km) occurred on top of the outcropping Trapanese unit. Conversely, the structural low between the Kumeta and Busambra structural highs hosted at least 2 km of sedimentary rocks whose origin could be either tectonic, gravitational or sedimentary. On the basis of geometric and thermal reconstructions and differential rotations of blocks, we suggest the following kinematic evolution for the study area: I) internal thrusting of the Imerese unit (located in a more internal position) during Serravallian times; II) overthrusting of Imerese unit/Numidian flysch above the Trapanese unit during Tortonian times; III) deformation of the Trapanese unit (since the end of Tortonian) with complex deformation, strongly influenced by inherited paleogeography.

The paleomagnetic investigation of the western Sicily Maghrebian belt has revealed since the 1970s that large clockwise (CW) rotations up to 140° with respect to the Hyblean-African foreland occurred synchronous with Tertiary shortening of the chain. The observation that rotations decrease stepwise from internal to external tectono-stratigraphic units led in the 1990s to a widely accepted model postulating that rotational thrust-sheet emplaced during forward orogenic propagation. More recently, other authors suggested that CW rotations from Sicily are conversely the result of late orogenic dextral strike-slip tectonics. Here we report on a paleomagnetic investigation of 30 Jurassic-Eocene sedimentary sites sampled mainly across the WNW-ESE Mt. Kumeta and Rocca Busambra ridges (Trapanese Unit), both bounded to the north by high-angle reverse faults with dextral strike-slip components. We find rotations of 110°-120° at faults of northern ridge margins, that decrease to 80°-90° at ~200 m to the south and rise again moving further south. Thus an excess rotation of 20°-40° due to dextral-strike slip shear is annulled to the regional rotational background of the Trapanese Unit at only 200 m from fault traces, translating to paleomagnetically-calculated strike-slip offsets not exceeding 600 m. Further north, seven sites sampled in the Imerese Unit, tectonically stacked above the Trapanese Unit, yield a ~130° rotation. Thus our data confirm that CW rotations in Sicily are predominantly related to thrust-sheet emplacement. Strike-slip tectonics has very limited relevance, and gives local rotations that fade out at only 200 m from fault planes. No differential rotation occurred between the Panormide and Imerese units, both characterized by 130° rotation values and likely representing contiguous paleogeographic domains separated by secondary thrust faults. Considering data from Mt. Kumeta, we constrain at 80° the rotation of the Trapanese Unit. The upper Cretaceous-Eocene Scaglia cover of both Mt. Kumeta and Rocca Busambra records an additional 20°-30° rotation with respect to the Jurassic ridge backbones, implying that it was décolled from the substratum. Assuming rigid nappe rotations and a rotation pole along the west Sicily coast, we derive (at a 13.5°E longitude) a total 230 km rotational shortening of the chain, and individual nappe displacements in the 20-120 km range, although further non-rotational shortening might have occurred. Thus paleomagnetism definitely represents a proof for the high allochthony of the Maghrebian chain of Sicily, consistently with recent seismic reflection data interpretations. By further assuming that rotations occurred during late Miocene thrusting events in the 12-5 Ma age window (except the Saccense Unit, later stacked onto the foreland), we derive an average 17°/Myr rotation rate, and a paleomagnetically-calculated average shortening rate of 3 cm/yr, that is again consistent with recent geological estimates.

From 2017 to 2019 a new rural settlement has been investigated in Contrada Castro (Corleone, Palermo) within the wider framework of the project ¿Harvesting Memories, Ecology and Archaeology of Monti Sicani landscapes¿ (Central-Western Sicily). Following a first occupation dated to the 6th-5th c. BC, the site was re-occupied between the Byzantine and Islamic period (7th-11th c. AD). Under the 10th-11th c. AD structures, a large square buildinghas been uncovered, that shows two subsequent phases dated from the mid-8th c. AD to the 9th c. AD. The structures belonging to the first phase of the building have revealed traces of pottery production, as indicated by the recovery of a two-chambered kiln as well as the presence of several ceramic wastes. This paper presents the material evidence connected to this recently unearthed building and discusses its implication in terms of craft production in a rural area during the transition from the Byzantine to the early Islamic period. This analysis enables us to reassess the existing chrono-typology for specific ceramic vessels, such as painted amphorae- in particular the ones showing band and sinusoidal decoration-and cooking wares recovered from this building. Moreover, the possibility to study specific pottery types in association with both a sound stratigraphic sequence ¿the kiln lies under the 10th-11th c. AD structuresand new radiocarbon data acquired from several key contexts, provides important insights into the material culture of a rural community living in the inland of Sicily between the 8th and 9th c. AD. In addition, we will also introduce the preliminary outcomes of the geological prospection carried out to identify the raw materials suitable for potting within the area, combined with the petrographic analysis of modern clay samples. Such integrated approach enables us to gain a better understanding on ceramic craft-technology, clay procurement strategies and more broadly the consumption of household pottery in the countryside of western Sicily between the late Byzantine period and the early Islamic age, adding to our knowledge of a crucial as well as ¿dark¿ period in the history of Early Medieval Sicily.

Seismogenic fault models and active deformation ones coupled with models of both earthquake rate and earthquake probability were recently used in a time-independent modelling. The integration of models allows to estimates the magnitude, location, and likelihood of potentially damaging earthquake ruptures in regions with high natural seismic hazard. Improvements of these models imply the recognition of the spatial geometry of the larger, active faults, deemed to be the source of the most damaging future earthquakes. However, identifying active faults and calculating their geologic slip rates for deriving earthquake rates are not easy tasks in regions inaccessible to direct field studies like active offshore areas. To improve the ability to define seismogenic fault models and active deformation models in offshore areas, we aim to develop a geophysical/geological method that allows to (a) identify the spatial geometry of active faults and fault systems in coastal areas, and (b) deduce the average long-term slip rates and recurrence interval, displacement per event, and elapsed time since the last event along the fault plane. The approach consists of innovative combination of geological and geophysical dataset, sampling methodology and GIS based on morphometric analysis. Preliminary results of this multidisciplinary approach applied to the coastal area of north Sicily document active deformation in an on-land sector of the Sicilian Maghrebian Chain and in its off-shore prolongation. Here we present results concerning the Palermo-Termini Imerese coastal sector based on a combination of: 1) structural data, 2) high-resolution reflection seismic data, 3) time series of GNSS data of the permanent stations of Palermo, Partinico, Prizzi, and Termini compared to the IGS station of Noto, 4) morphometric analysis of high-resolution digital elevation data for the hydrographic basins of the Oreto, Eleuterio, Milicia, San Leonardo, Torto and Imera Settentrionale rivers, and 5) seismological data. In the area of the Capo Zafferano promontory, Pleistocene conglomerates and grainstones are affected by recent tectonic deformation. In particular, at two sites near the village of Porticello we observed two sets of N-S to NNW-SSE and NE-SW striking deformation bands. Both sets have an almost vertical dip and show mutual cross-cutting relationships, suggesting their contemporaneous development. The N-S to NNW-SSE striking set shows left-lateral strike slip kinematic. At place, the deformation bands affect also Upper Pleistocene (Tyrrhenian) bio-calcarenites. In the off-shore, a number of seismic units, bounded by unconformities, were identified on seismic lines. The unit of inferred late Pleistocene age appears to be folded and faulted. Faults generally have an inclination of ca. 50°, small displacements up to 10 m and are sealed by the unit of inferred post-LGM age. Only a limited number of these faults are observed moving ca. 3 km offshore towards the NE. The average values of the velocity vectors obtained for the Palermo, Partinico, Prizzi, and Termini Imerese stations are 4.55, 2.97, 2.96, and 2.15 mm/yr, respectively. The direction of the velocity vectors for all stations is oriented towards the IGS reference station of Noto. The relative displacements of the Termini Imerese, Partinico and Prizzi stations respect to Palermo station are most equal to 0.5 mm/yr. Also, the directions of vectors suggest a clockwise rotation. The drainage network analysis highlights that the trunk streams of Eleuterio and San Leonardo drainage networks are asymmetric towards SE and the absolute asymmetry are ~ 3 and ~ 2 km, respectively. On the contrary, the trunk streams of the Milicia, Torto and Imera Settentrionale rivers are asymmetric towards W-NW with an asymmetry ranging from 3.5 up to 4 km. The Oreto stream does not show any evidence of lateral shift. Hypsometric analysis shows two types of statistical distributions of elevation classes. The latter have a bi-modal distribution for the Eleuterio, Oreto and Torto basins while uni-modal for the Milicia and San Leonardo basins. Values of the hypsometric integral are ~ 0.4 for the Milicia, San Leonardo and Torto basins, ~ 0.5 for the Eleuterio basin and 0.35 for the Oreto basin. The study area has been struck in the past centuries by several significant earthquakes of I0 ≥ 6. Mainly low-to-moderate magnitude seismicity, instead, occurred in this sector in the more recent times, showing highest earthquake concentration in the Tyrrhenian off-shore of the study area with respect to the onshore sector. To furnish a first constraint on seismogenic sources lying in this area, we performed hypocenter location and focal mechanism computation of the seismicity that occurred in the last thirty years. Then, we jointly evaluated data and information coming from historical seismicity with the results obtained by the geophysical, geological, and seismological analyses performed in order to better characterize the possible seismogenic sources present in the study region.

Tettonica sinsedimentaria del Pliocene inferiore nei Monti delle Madonie settentrionali (Sicilia). L'analisi stratigrafico-strutturale condotta in un piccolo bacino infra-pliocenico nelle Madonie settentrionali (Lascari-Capo Plaja) permette di descrivere un evento tettonico sin-sedimentario. La sinclinale EW in cui si sviluppa il bacino sintettonico appartiene ad un sistema di pieghe nord vergenti che deformano un piano di sovrascorrimento più antico (Langhiano-Serravalliano). La geometria di crescita che caratterizza il pattern stratale dei depositi pliocenici e la discordanza angolare alla base suggeriscono che la nucleazione di queste strutture compressionali si possa essere realizzata almeno dal Messiniano al Pliocene inferiore. Le strutture nordvergenti riconosciute nell'area in studio mostrano stile deformativo ed orientazione compatibile con le fasi tardive della strutturazione riconosciute in Sicilia occidentale da autori precedenti. I dati raccolti sono pertanto un contributo alla datazione delle strutture traspressive nord vergenti che seguono la messa in posto dei sovrascorrimenti principali e che sono connesse al sollevamento della sottostante piattaforma.

Rilievi geologici finalizzati alla compilazione di carte geologiche in Sicilia nord-occidentale (Progetto CARG) Vengono descritti i risultati del rilevamento di numerosi fogli geologici a scala 1:50.000 ubicati nella Sicilia settentrionale (dalle Isole Egadi fino ai Monti delle Madonie), eseguito nel quadro del Progetto CARG. I rilievi sul terreno sono stati integrati con i dati di sottosuolo provenienti da profili sismici a riflessione e perforazioni profonde. I risultati ottenuti offrono un quadro a scala regionale dell’assetto stratigrafico-strutturale di uno dei settori più complessi della Catena Siciliano-Maghrebide. Sono state ricostruite le successioni stratigrafiche dei paleodomini meso-cenozoici, così come la loro progressiva deformazione avvenuta in due principali eventi tettonici, il più antico tra il Langhiano ed il Tortoniano, il più recente tra la fine del Miocene ed il Pleistocene inferiore.

The coastal landscape of the Kachchh Upland (KU) region (NW-India) changed over the last few thousand years from a shallow marine gulf to a salty desert (1-4 meters asl). In this area, bordered to the south by the Northern Hill Range (NHR), the tectonic-climatic interaction triggered the sea level fall from +2/4 m circa (6000-2000 BP) to zero. An ancient river pattern deposited a tidally regulated delta area during the sea level fall that stopped 2000-3000 years ago due to tectonic activity and a dry climate. Deltaic-alluvial fans (DAF) in front of the NHR suggest that the KU's tectonic activity led to fast landscape evolution. We explored such drastic changes by integrating scientific information from a multidisciplinary literature review, identifying terraces and DAFs, and inferring faults through landform recognition, quantitative morphometry, and field surveys. Our interpretation, summarized in a map, provides new information on active processes along the NHR.

We present and discuss the results of a geomorphological and geological study aimed at reconstructing the Plio-Quaternary evolution of the NW Sicily coastal belt, a low strain rate region in the central Mediterranean Sea. We performed morphometric and field analysis of Quaternary marine terraces extracting more than 300 shoreline location points subdivided into six orders. The obtained dataset was validate by investigating the morphological changes along topographic profiles and comparing the extracted locations and elevations with the stratigraphic boundaries in the Plio-Quaternary units. We distinguished two contiguous coastal sectors characterized by different paleo-shoreline elevations and Plio-Quaternary evolution, whose estimated uplift rates fit well with the well-known, regional eastward uplift rate increase along the Northern Sicilian continental margin. Obtained results, summarized in a geomorphological map and a morpho-evolutionary model, provide new valuable data to characterize the active deformation processes and the seismotectonic setting in this critical sector of the Africa-Europe plate boundary.

This paper aims at an interdisciplinary, archaeological and archaeometric characterisation of the western Greek amphorae series produced in late Archaic and Classical-period Agrigento (southern Sicily). The research is based on a macroscopic examination, according to the standardised methods of Fabrics of the Central Mediterranean (FACEM), combined with petrographic analyses of 21 amphorae samples of presumed local fabric found in Agrigento itself. These were found in the artisanal area outside Porta V, in the excavations South of the temple of Zeus, and in several Sicilian consumption sites. Furthermore, a selection of 12 coarse ware samples and three tiles, all of supposed local manufacture and unearthed in Agrigento, has been investigated. For comparison, 12 raw clays sampled in the gullies between the Tempio di Giunone and the Tempio della Concordia have been included in this study and are complimented by chemical analyses (ICP-MS and ICP/OES) undertaken on a group of 19 ceramic samples and seven raw materials. As a result, our study confirms the local manufacture of the entire selection of 36 ceramic samples and the more than acceptable petrographic and chemical homogeneity of the ceramic pastes produced with locally sourced clays. The identification of a production of western Greek wine (?) amphorae in Agrigento dating from the late 6th-4th century BCE breaks ground for a better understanding of the colony's economic development during the late Archaic and Classical periods. The city has to be regarded, in fact, as one of the major global players within the wider frame of Sicilian commercial interaction, especially during the 5th century BCE.

18 pages, 13 figures, 1 table, We present here for the first time a morpho-structural study of the submarine sector of the Ustica volcanic edifice, located in the south-western Tyrrhenian Sea, considered as an inactive volcanic system, middle Pleistocene in age. The main aim of this research study is to unravel the submarine dynamics along the slope sectors of the Ustica volcano, in order to provide new insights on one of the most tectonically active regions of the Central Mediterranean during the Quaternary. We analysed and interpreted an integrated seismo-acoustic data set consisting of multibeam swath-bathymetry, sub bottom profiles, single-channel seismic reflection records, all of them acquired during the last two decades. The seismostratigraphic analysis indicates that the Ustica volcano is composed by a sequence of lava flows and pyroclastic products, whose geometry can be interpreted as the consequence of combined upward growing and northward shifting of the volcanic centers. The mapped geomorphological elements distributed along the submerged slopes were classified based on their specific morphogenetic process. The achieved results reveal that volcanic, tectonic, oceanographic and gravity processes interacted in shaping the complex current physiography of the volcanic edifice, which is characterized by extremely uneven submarine flanks. The northern region is characterized by the widespread occurrence of well-preserved cones, probably linked to the last submarine volcanic activity of the area. Along the eastern sector, elongate gullies and linear furrows locally incise the shelf break and develop downward producing slope failures. Furrows and gullies represent the main conduits for flushing sediments through various types of flows and mass wasting, from the shallow sectors to the bathyal plain. Along the southern and eastern region slope failures processes carve almost totally of the shelf edge and mainly propagate through retrograding collapses. Further on, the southern region is mainly shaped by E-W and N-S trending fault escarpments that may have triggered the largest slope failures of the area. The main results of this study contribute to improve the understanding of the geological processes and geodynamic activity between the Northern Sicily Continental Margin and the Tyrrhenian Basin and represent a baseline for assessing the geo-hazard potential on the Ustica Island, We acknowledge the CARG Project (Geological Maps of Italy) funded by the ISPRA-Italian Geological Survey and the Italian National Research Projects MaGIC (Marine Geological Hazard along the Italian Coast) funded by the Italian Civil Protection Department.-- With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

This study presents a global overview of the submerged speleothems used to reconstruct paleo sea levels and reports new results from two stalactites collected in the Mediterranean Sea. Coastal cave deposits significantly contributed to the understanding of global and regional sea-level variations during the Middle and Late Quaternary. The studied speleothems cover the last 1.4 Myr and focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. The results indicate that submerged speleothems represent extraordinary archives that can provide detailed information on former sea-level changes. The two stalactites collected in the central Mediterranean Sea, at Favignana and Ustica islands (Sicily, Italy), are both characterized by continental, phreatic or marine layers. The U-Th and 14C ages of the new speleothems provide results of great interest for relative sea-level changes over the last 1000 years.

A three-stage evolution has characterized the Sicilian Fold and Thrust Belt (SFTB) during the last 15 My: two main thin-skinned shortening events involving mainly Meso-Cenozoic carbonate units, followed by thick-skinned thrusting involving Plio-Pleistocene deposits in the frontal area as well as the crystalline basement in the inner and deeper sector of the chain. We investigated the northern Sicily continental margin, by using differently-penetrative seismic reflection data and new field surveys, which revealed, both offshore and onshore, north-vergent compressional structures that affected the tectonic edifice during Quaternary time. These structures, correlated with the kinematic setting pointed out by seismicity and GPS measurements, could disclose an important change in distribution and orientation of deformation in the frame of the Africa-Europe convergence. Our hypothesis is that the most recent tectonic processes in the northern Sicily continental margin are representative of a jump of the deformation from the frontal area of the SFTB in the Sicily Channel to the inner sector in the Southern Tyrrhenian Sea. This study is in agreement with recent interpretations about a change in the subduction polarity in the central Mediterranean orogenic system, as a consequence of the ongoing collision of the African promontory with the thinned continental to oceanic sectors (Algerian and Tyrrhenian basins) of the European plate. The seismic activity associated with the north-vergent thrust could have implication for the assessment of the seismic risk in the Central Mediterranean and understanding of active structures in marine areas that could be responsible for tsunami hazard.

Geomorphological Tools for Mapping Natural Hazards.-- 12 pages, 7 figures, supplemental material https://doi.org/10.1080/17445647.2020.1866703.-- Software: The geomorphological main map and the Figures in the text were compiled using GLOBAL MAPPER, Surfer and Quantum-G GIS Software and redesigned to print with Adobe Illustrator, In this paper we present geomorphological hazard mapping of the San Vito Peninsula offshore (Sicilian margin of Tyrrhenian Sea), characterised by a very narrow continental shelf and a very dipping, tectonically active continental slope, no far from a seismogenic belt. The data set consists of morpho-bathymetric models achieved by means of multibeam survey and scattered high resolution seismic profiles. The morpho-bathymetric study highlighted some potential sites of geomorphological hazards, the most representative of which are: (i) two canyons developing from the upper slope off San Vito Cape down to the Erice basin; (ii) a dense network of small incisions across the upper slope; (iii) a very active landslide, developed onland and extending in the continental shelf close to the Scopello village. The geomorphological features that can generate submarine hazard are represented by: unstable sediment packages into canyon heads or along the upper slope; submarine canyons with regressive erosion; coastal landslides, With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

In order to investigate the variability of helium degassing in continental regions, its release from rocks and emission into the atmosphere, here we studied the degassing of volatiles in a seismically active region of northern Italy (MwMAX = 6) at the Nirano-Regnano mud volcanic system. The emitted gases in the study area are CH4–dominated and it is the carrier for helium (He) transfer through the crust. Carbon and He isotopes unequivocally indicate that crustal-derived fluids dominate these systems. An high-resolution 3-dimensional reconstruction of the gas reservoirs feeding the observed gas emissions at the surface permits to estimate the amount of He stored in the natural reservoirs. Our study demonstrated that the in-situ production of 4He in the crust and a long-lasting diffusion through the crust are not the main processes that rule the He degassing in the region. Furthermore, we demonstrated that micro-fracturation due to the field of stress that generates the local seismicity increases the release of He from the rocks and can sustain the excess of He in the natural reservoirs respect to the steady-state diffusive degassing. These results prove that (1) the transport of volatiles through the crust can be episodic as function of rock deformation and seismicity and (2) He can be used to highlight changes in the stress field and related earthquakes.

Temperature-dependent clay mineral assemblages, vitrinite reflectance, and one-dimensional (1-D) thermal and three-dimensional (3-D) geological modeling of a Neogene wedge-top basin in the Sicilian fold-and-thrust belt and its pre-orogenic substratum allowed us to: (1) define the burial history of the sedimentary succession filling the wedge-top basin and its substratum, (2) reconstruct the wedge-top basin geometry, depocenter migration, and sediment provenance through time in the framework of a source-to-sink system, and (3) shed new light into the kinematic evolution of the Apennine-Maghrebian fold-and-thrust belt.The pre-orogenic substratum of the Scillato basin shows an increase in levels of thermal maturity as a function of stratigraphic age that is consistent with maximum burial to 3.5 km in deep diagenetic conditions. In detail, Ro% values range from 0.40% to 0.94%, and random ordered illite-smectite (I-S) first converts to short-range ordered structures and then evolves to long-range ordered structures at the base of the Imerese unit. The wedge-top basin fill experienced shallow burial (∼2 km) and levels of thermal maturity in the immature stage of hydrocarbon generation and early diagenesis. Vitrinite reflectance and mixed-layer I-S values show two populations of authigenic and inherited phases. The indigenous population corresponds to macerals with Ro% values of 0.33%–0.45% and I-S with no preferred sequence in stacking of layers, whereas the reworked group corresponds to macerals with Ro% values of 0.42%–0.47% and short-range ordered I-S with no correlation as a function of depth.Authigenic and reworked components of the Scillato basin fill allowed us to unravel sediment provenance during the Neogene, identifying two main source areas feeding the wedge-top basin (crystalline units of the European domain and sedimentary units of the African domain), and to detect an early phase of exhumation driven by low-angle extensional faults that predated Neogene compression.

We describe soft-sediment deformation structures into the Upper Triassic cherty limestone outcropping in the Pizzo Lupo section (Central Sicily, Italy), pertaining to the deep-water palaeodomain of the Southern Tethyan margin. In the study section, mainly consisting of thin-bedded mudstone/marl alternations with bedded chert intercalations, some lithofacies have been separated on the basis of the abundance of the calcium carbonate/clay content and the overall textural features. The deformational structures, displaying different deformational styles as folded and faulted beds, disturbed layers, clastic dikes, and slumps occur mainly in the deformed horizons that involve marl-dominated lithofacies. Small-scale water-escape structures involve beds with nodular fabric. Synsedimentary faults affect the mud-limestone dominated lithofacies, which are characterized by fault-rotating blocks producing lateral thinning. These bodies appear to have moved coherently along an overall planar surface. We relate these soft-sediment deformations to slump sheets, associated with down-slope sliding of sedimentary masses. The deformation mechanism and driving force for these soft-sediment deformations are due essentially to gravitational instability and dewatering. Detailing, rotational (slump) and translational (glide) slides and water-escape are the main processes causing the distinguished deformational styles. The synsedimentary extensional tectonics that affected the Upper Triassic pelagic deposits was the triggering process responsible for the instability of the seafloor inducing loss of coherence of the unconsolidated sediments on the sea bottom, developing a large number of gravity-driven slides. The analysis of both of these SSDSs and their relationships with the structural scenario allow us to hypothesise that they are seismically-induced.

An integrated analysis of 2D high-resolution shallow seismic refraction tomographies (SRT) and electrical resistivity tomographies (ERT) has been carried out along a slope where the presence of a fault zone was assumed. It was also applied a post-inversion k-means cluster analysis of the P-wave velocity, the density of the seismic rays and the electrical resistivity of the interpretation models. Distribution maps of the cluster in multi-space were built, allowing to better definethe lateral geometry of a NE-SW directed band composed of intensely tectonized carbonate breccias. Finally, the fracturing and kinematic analysis on fault planes observed along the trenches, highlighted systems of left and right-lateral transtensional faults NW-SE, NNW-SSE and NE-SW trending, respectively, which antedate the extensional tectonic event. The reconstructed stress-field-orientation related to the latter tectonic system does not comply with the active stress field for this sector of the Sicilian chain. Moreover all the tectonic structures are sealed by Upper Pleistocene – Holocene continental deposits.

During the Messinian inherited palaeo-topography and ongoing deformation conditioned the depositional environments of the Mediterranean region, already strongly influenced by the effects of the salinity crisis. It occurred mainly in the central region, where seabed at that time is expected to be very uneven and shallower than Western and Eastern Mediterranean. Indeed in this area as from 15 Ma the Sicilian Fold and Thrust Belt (SFTB) was originating, characterized by a multi-stage evolution. Two main shortening events generated and developed at different structural levels (shallow- and deep-seated thrusts following a thin-skinned thrust-model) and at different time intervals, involved mainly the Meso-Cenozoic carbonate units of the ancient African passive continental margin; a more recent thick-skinned thrusting involved the Plio-Pleistocene deposits in the frontal area, as well as the crystalline basement in the internal sector of the chain. Just in the Messinian time interval along the internal sectors of this edifice the transition from shallow to deep seated tectonics was recorded. On top of the SFTB different types of basins originated progressively in response to the shortening wave. Depending on their position and related active processes during the Messinian we can distinguish: intramountain (mainly post-tectonic), thrust-top (syn-tectonic), and foreland (pre-tectonic) Messinian basins, with different characters and geometries. Our results are only preliminary and could represent a first approach towards a better understand of the present complex distribution of the different variety of the Messinian sequences. The next step of this study should be the palinspastic restoration of the strongly deformed Messinian successions, in order to reconstruct a more detailed Mediterranean paleogeography.

Neogene-Quaternary wedge-top-basins arose during the Sicilian fold and thrust belt (FTB) build-up. The infilling sedimentary successions are: i) middle-upper Miocene silicoclastics succession, accommodated on top of the accreted Sicilide and Numidian flysch nappes; ii) upper Miocene-lower Pliocene deepening-upwards sediments unconformably overlying the inner Meso-Cenozoic deep-water, Imerese and Sicanian thrust units; iii) Upper Pliocene-Quaternary coastal-open shelf deposits unconformably covering (in the outer sector of the FTB) a tectonic stack (Gela thrust system). These successions are characterized by a basal unconformity on the deformed substrate believed to be the depositional interface common both to the coeval wedge-top and foredeep basins. The tectono-sedimentary evolution of the syn-tectonic basins was controlled by the progressive deepening of the structural levels, which were active during the growing of the FTB. The palinspastic restoration of a crustal geological transect in central Sicily points to: i) the occurrence of two subsequent, basal main thrusts (MT1 and MT2) active during the Neogene-middle Pleistocene tectonic evolution, as well as ii) a decrease in slip- and shortening-rate, estimated for the later MT2 as compared to earlier MT1 basal main thrust. The foreland-basin system evolution recorded during these two steps suggests: – the regional lithofacies distribution, during late Tortonian-early Pliocene, accounted for a wide depozone including the Iblean plateau and its offshore;– a crucial change was recorded by the late Pliocene-Pleistocene wedge-top depozone, when the deeper basal main thrust (MT2) involved and thickened (in the inner sector of the FTB) the crystalline basement (thin- to thick-skinned thrust tectonics); this change influenced the depozones, progressively narrowing up to the present-day setting. As regards this general evolutionary framework, thin-skinned and thick-skinned thrust tectonics can be recognized in the Sicilian FTB evolution. The late Tortonian-early Pliocene, thin-skinned thrust tectonics include two main tectonic events, a “shallow-seated” Event 1 and a “deep-seated” Event 2, with the Pliocene-Pleistocene thick-skinned thrust tectonics representing a third tectonic event (Event 3).

We present a 1:25.000 scale geological map of the Kumeta-Pizzuta ridge in north-western Sicily (Italy), achieved by integrating stratigraphic, structural and geophysical data. In this area, the tectonic edifice results from the piling-up of deep-water-, carbonate platform- and pelagic platform-derived tectonic units (Imerese and Sicilide, Panormide and Trapanese domains, respectively) resulting from deformations of the former southern Tethyan continental margin. The structural setting shows interference of tectonic events, different types of structural styles and different scales of deformational patterns. Early overthrust of the Imerese on the Trapanese units (since the late Serravallian) was followed by wedging at depth of the Trapanese units (after the Tortonian). The wedging implied re-embrication and shortening into the overlying Imerese tectonic units and so produced the main folding and compressive to transpressive structures along the Kumeta-Pizzuta Ridge. Seismic reflection profiles integrated with field data reveal that the main E-W-trending anticlines have been offset by high-angle reverse faults flattening at depth until they connect with low-angle, regionally widespread, decollement surfaces with a northward tectonic transport. This setting supports backthrusting along transpressional faults in the study area, ruling out that the Kumeta ridge is a positive flower structure related to a near-vertical deep, crustal, shear zone as formerly suggested.

In this paper we present and discuss data concerning the morphostructural evolution at Ustica Island (Tyrrhenian Sea, Italy) during Late Quaternary. New insights on the relative sea-level changes of Ustica are coming from data collected during a geomorphological field survey around the island, together with the bathymetric analysis of the surrounding seabed and 14C datings on samples of speleothems, flowstones and marine shells found inside three selected sea caves. The survey was mainly accomplished on June 2015 through the first complete snorkel investigation off the about 18 km-long volcanic coast of the island, which allowed to precisely define location, relationship and morphometric features of coastal landforms associated with modern sea level. This study highlights the occurrence, for the first time in the Mediterranean, of tidal notches in correspondence of carbonate inclusions in volcanic rocks. The elevation of the modern tidal notch suggests that no significant vertical deformations occurred in the southeastern and eastern sectors of Ustica in the last 100 years. However, the presence of pillow lavas along the coast demonstrates that Ustica was affected by a regional uplift since the Late Quaternary, as also confirmed by MIS5.5 deposits located at about 30 m a.s.l., which suggests an average uplift rate of 0.23 mm/y. Radiocarbon dating of fossil barnacles collected inside the Grotta Segreta cave indicate an age of 1823 ± 104 cal. BP. The difference in height with respect to living barnacles in the same site suggests that their present elevation could be related to stick-slip coseismic deformations caused by the four earthquake sequences (two of which with Mw = 4.63 ± 0.46) that strongly struck the island between 1906 and 1924. © 2017 Elsevier B.V.

We illustrate the tectono-sedimentary evolution of a Jurassic-Cretaceous intraplatform basin in a fold and thrust belt present setting (Cala Rossa basin). Detailed stratigraphy and facies analysis of Upper Triassic-Eocene successions outcropping in the Palermo Mts (NW Sicily), integrated with structural analysis, restoration and basin analysis, led to recognize and describe into the intraplatform basin the proximal and distal depositional areas respect to the bordered carbonate platform sectors. Carbonate platform was characterized by a rimmed reef growing with progradational trends towards the basin, as suggested by the several reworked shallow-water materials interlayered into the deep-water succession. More, the occurrence of thick resedimented breccia levels into the deep-water succession suggests the time and the characters of synsedimentary tectonics occurred during the Late Jurassic. The study sections, involved in the building processes of the Sicilian fold and thrust belt, were restored in order to obtain the original width of the Cala Rossa basin, useful to reconstruct the original geometries and opening mechanisms of the basin. Basin analysis allowed reconstructing the subsidence history of three sectors with different paleobathymetry, evidencing the role exerted by tectonics in the evolution of the narrow Cala Rossa basin. In our interpretation, a transtensional dextral Lower Jurassic fault system, WNW-ESE (present-day) oriented, has activated a wedge shaped pull-apart basin. In the frame of the geodynamic evolution of the Southern Tethyan rifted continental margin, the Cala Rossa basin could have been affected by Jurassic transtensional faults related to the lateral westward motion of Africa relative to Europe.

We present a 1:10,000 scale geological map of Marettimo Island and its offshore (Egadi Archipelago, central Mediterranean Sea). The map was achieved by integrating a new geological survey with data from recent, marine, geological and geophysical surveys acquired along the adjacent continental shelf. The island is composed of a Mesozoic, mostly carbonate platform succession, which is overlain by continental to coastal marine Quaternary deposits. Extensional tectonics have affected the carbonate platform since the Late Triassic producing an initial increase of accommodation space that was filled by interbed breccias, marls and calcareous marls. During the Jurassic, a NE-SW-directed normal fault-bounded structural lows where thick beds of megabreccias accumulated followed upwards by cherty limestone and bedded cherts. During the building of the chain, the compressional tectonics generated a southeast-verging tectonic wedge, displaced by subsequent transpression. During the Quaternary, repeated sea-level changes shaped a rough erosional surface along the inner shelf and controlled the lateral facies variation of the continental and marine coastal deposits along the present day coastline.

We illustrate the tectono-sedimentary evolution of a Jurassic–Cretaceous intraplatform basin in a fold and thrust belt present setting (Cala Rossa basin). Detailed stratigraphy and facies analysis of Upper Triassic–Eocene successions outcropping in the Palermo Mts (NW Sicily), integrated with structural analysis, restoration and basin analysis, led to recognize and describe into the intraplatform basin the proximal and distal depositional areas respect to the bordered carbonate platform sectors. Carbonate platform was characterized by a rimmed reef growing with progradational trends towards the basin, as suggested by the several reworked shallow-water materials interlayered into the deep-water succession. More, the occurrence of thick resedimented breccia levels into the deep-water succession suggests the time and the characters of synsedimentary tectonics occurred during the Late Jurassic. The study sections, involved in the building processes of the Sicilian fold and thrust belt, were restored in order to obtain the original width of the Cala Rossa basin, useful to reconstruct the original geometries and opening mechanisms of the basin. Basin analysis allowed reconstructing the subsidence history of three sectors with different paleobathymetry, evidencing the role exerted by tectonics in the evolution of the narrow Cala Rossa basin. In our interpretation, a transtensional dextral Lower Jurassic fault system, WNW–ESE (present-day) oriented, has activated a wedge shaped pull-apart basin. In the frame of the geodynamic evolution of the Southern Tethyan rifted continental margin, the Cala Rossa basin could have been affected by Jurassic transtensional faults related to the lateral westward motion of Africa relative to Europe.

A description of the stratigraphic setting and tectonic evolution of the Late Neogene Ciminna basin (Northern Sicily)

Wedge top basins are key elements for unravelling the tectonic evolution of fold-and-thrust belts. In detail, their thermal signature and sedimentary fill records modes and time of exhumation of their edges. The Scillato basin is a wedge-top basin located in the central-northern sector of the Sicilian fold-and-thrust belt (western sector of the Madonie Mts). Upper Serravallian-upper Tortonian succession composed by up to 1,200 m thick delta-river to open marine siliciclastic sediments, fills the basin. This succession lies on a deformed substrate made up of thrust sheets composed of Numidian Flysch, Sicilidi and Imerese units stacked with a SW tectonic transport. The basin fill records a polyphase tectonic evolution with two non-coaxial compressional to transpressional tectonic events since the middle-late Miocene that caused changes in basin geometry, uplift of local structural highs and creation of new source areas for sediments. Organic matter optical analysis and X-ray diffraction of clay minerals have been performed from the basin fill and the substrate to unravel source to sink evolution. The organic matter shows two separate clusters of vitrinite reflectance (Ro%) in the basin fill. The first one has values of 0.4-0.5 Ro% with an increase of thermal maturity with depth. The second one has values of 0.7-0.8 Ro%, indicating reworked, more mature kerogen. The substrate shows higher Ro% values: from 0.6% in Numidian Flysch up to 0.9 % at the base of the Imerese unit. XRD on clay minerals presents, among the other phases, two population of mixed layers Illite-Smectite (R0 and R1 stacking order) in the wedge top basin. The first population, R0, indicates thermal maturity levels in agreement with the Ro% and is authigenic; the second one, R1, has detrital origin. The substrate shows R3 in the older formations of the Imerese unit and R1 in younger formations of the Imerese unit and Numidian Flysch. Coupling the results from the organic and inorganic fine fractions of the studied sedimentary successions, it has been possible to: 1. quantify the maximum sedimentary/tectonic loads and exhumation the wedge top and the substrate underwent; 2. identify, at least, two distinct source areas for the basin fill changing through time: the Numidian flysch in the initial stage of the basin development and the Imerese unit in the final stages of basin filling.

Backthrusting, nappe refolding, and normal faulting frequently characterize late collisional stage of an orogen. Shortening driven by backthrusting is widely reported in the Alpine orogen, and it has been proposed to be responsible for the increase of subsidence. Moreover delamination and backthrusting has been considered as related to subcritical condition of a Coulomb-type accretional wedge (Torres Carbonell et al., 2011). The Sicilian Fold and Thrust Belt (SFTB) was characterized by a three-stage evolution during the last 15 My: two main shortening events generated and developed at different structural levels (shallow- and deep-seated thrusts in thinskinned thrust-model) and different time intervals, involving mainly the Meso-Cenozoic carbonate units of the ancient African passive continental margin, followed by a more recent thick-skinned thrust-model involving the Plio-Pleistiocene deposits in the frontal area as well as the crystalline basement in the internal sector of the chain. We investigated the northern Sicily continental margin, by using differently-penetrative seismic reflection data, including a deep crustal profile, calibrated with detailed field surveys and borehole data. On the whole, the tectonic edifice appears to be interested, both offshore and onshore, by a peculiar structural style that can be interpreted as a triangle zone bounded, on the southern side by N-dipping high-angle transpressional faults (e.g. Busambra fault), mainly Early Pliocene to Early Pleistocene in age, and on its northern side, by high-angle S-dipping thrusts (e.g. Kumeta fault), deeply connected with a low-angle décollement layer. In the outer sector of the SFTB, double-verging structures (with NW and SE-tectonic transport) have been described for the Plio-Pleistocene evolution of the Gela Thrust System. The southern Tyrrhenian region is also interested by normal faulting and subsidence (e.g. Cefalù basin), delamination processes, and widespread deep seismicity. A late Miocene-Quaternary northern migration of the plate margin producing opposite-verging structures is reported in the northern Africa plate boundary (e.g. NW Algeria Neogene margin; Mauffret, 2007). A plate boundary reorganization during the latest 0.8–0.5 My with the development of backthrusts have been documented in the Mediterranean region (Goes et al., 2004). Our hypothesis is that the most recent tectonic processes in the study region are representative of a late collisional stage in the northern Sicily mountain building and at a larger scale could be a precursor of a change in the subduction polarity in the central belt of Mediterranean, as a consequence of the ongoing collision of the African promontory with the thinned continental to oceanic sectors (Algerian and Tyrrhenian basins) of the European plate.