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A comparative analysis of bedform fields along the submarine flanks of insular volcanoes, characterized by different morpho-structural settings, volcanic and meteo-marine regimes (Vanuatu, Kermadec, Bismark, Madeira and Aeolian archipelagos), is presented here to provide insights on the size distribution, morpho-dynamic and genesis of such bedforms. Two main types of bedforms are recognized according to their size, location and preconditioning/triggering processes. Small-scale bedforms have wavelengths of tens to hundreds of metres and wave heights of metres. Because of their small-size, they are typically not recognizable at water depths greater than 400 m from vessel-mounted bathymetric surveys. Few examples of small-scale bedforms are reported from upper volcanic flanks, where steep gradients commonly hinder their formation. Their recognition is mostly limited to the thalweg of shallow and flat-bottomed channels that carve the insular shelf on slope gradients

[Conceptual stratigraphic section of the Po di Pila clinothem throughout the 4‐years bathymetric surveys. Bottom, year 2013: the Po di Pila shows compound progradation in the central sector, with a subaqueous Rollover Point (RP) at 8 m, whereas in the northern sector a single RP develops at an average of 3 m water depth. Center, year 2014: the Po di Pila shows compound progradation in both (central and northern) sectors, but a destruction phase in the central sector (eroded topset and RPs separated by a collapse depression) and a constructional phase in the northern sector (normal regression with compound clinothems) occur simultaneously. Top, year 2016: the Po di Pila shows a subaqueous RP at an average 5 m of water depth of the transverse bar in the central sector, whereas compound progradation is recorded in the northern sector. Note that in a subaerial delta, such as the modern Po Delta, subaerial RPs correspond to breaks in slope associated with the presence of mouth bars, whereas subaqueous nearshore RPs correspond to breaks in slope due to the presence of transverse bars and delta lobes. , Abstract Reconstructions of ancient delta systems rely typically on a two‐dimensional (2D) view of prograding clinothems but may miss their three‐dimensional (3D) stratigraphic complexity which can, instead, be best documented on modern delta systems by integrating high‐resolution geophysical data, historical cartography, core data and geomorphological reconstructions offshore. We quantitatively compare three precisely positioned, high‐resolution multi‐beam bathymetry maps in the delta front and pro delta sectors (0.3 to 10 m water depth) of Po di Pila, the most active of the modern Po Delta five branches. By investigating the detailed morphology of the prograding modern Po Delta, we shed new light on the mechanisms that control the topset to foreset transition in clinothems and show the temporal and spatial complexity of a delta and its pro delta slope, under the impact of oceanographic processes. This study documents the ephemeral nature of the rollover point at the transition between sandy topset (fluvial, delta plain to mouth‐bar) and muddy seaward‐dipping foreset deposits advancing, in this case, in >20 m of water depth. Three multibeam surveys, acquired between 2013 and 2016, document the complexity in space and time of the topset and foreset regions and their related morphology, a diagnostic feature that could not be appreciated using solely 2D, even very high‐resolution, seismic profiles. In addition, the comparison of bathymetric surveys gathered with one‐year lapses shows the migration of subaqueous sand dunes on the clinothem topset, the formation of ephemeral cut‐and‐fill features at the rollover point (few m below mean sea level), the presence of collapse depressions derived by sagging of sediments and fluid expulsion (possibly induced by storm waves) on the foreset, and splays of sand likely reflecting gravity flows on the lower foreset. Though the modern Po Delta is anthropogenic in many respects, its subaqueous clinothem can be studied as a scale model for ancient clinothems that are less resolved geometrically and far less constrained chronologically.]

The NE Sicilian continental margin is largely affected by canyons and related landslide scars. Two main types of submarine canyons are recognizable: The first type carves the shelf up to depths

Seismological data recorded in the Ionian Sea by a network of seven Ocean Bottom Seismometers (OBSs) during the 2017–2018 SEISMOFAULTS experiment provides a close-up view of seismogenic structures that are potential sources of medium-high magnitude earthquakes. The high-quality signal-to-noise ratio waveforms are observed for earthquakes at different scales: teleseismic, regional, and local earthquakes as well as single station earthquakes and small crack events. In this work, we focus on two different types of recording: 1) local earthquakes and 2) Short Duration Events (SDE) associated to micro-fracturing processes. During the SEISMOFAULTS experiment, 133 local earthquakes were recorded by both OBSs and land stations (local magnitude ranging between 0.9 and 3.8), while a group of local earthquakes (76), due to their low magnitude, were recorded only by the OBS network. We relocated 133 earthquakes by integrating onshore and offshore travel times and obtaining a significant improvement in accuracy, particularly for the offshore events. Moreover, the higher signal-to-noise ratio of the OBS network revealed a significant seismicity not detected onshore, which shed new light on the location and kinematics of seismogenic structures in the Calabrian Arc accretionary prism and associated to the subduction of the Ionian lithosphere beneath the Apennines. Other signals recorded only by the OBS network include a high number of Short Duration Events (SDE). The different waveforms of SDEs at two groups of OBSs and the close correlation between the occurrence of events recorded at single stations and SDEs suggest an endogenous fluid venting from mud volcanoes and active fault traces. Results from the analysis of seismological data collected during the SEISMOFAULTS experiment confirm the necessity and potential of marine studies with OBSs, particularly in those geologically active areas of the Mediterranean Sea prone to high seismic risk.

Small-scale landslides affecting insular and coastal volcanoes are a relevant geohazard for the surrounding infrastructures and communities, because they can directly impact them or generate local but devastating tsunamis, as demonstrated by several historical accounts. Here, a review of such landslides and associated predisposing/triggering mechanisms is presented, with particular reference to the submarine volcanic flanks. We take into account, as a case study, the instability phenomena occurring on the Sciara del Fuoco (SdF, hereafter), a 2-km wide subaerial-submarine collapse scar filled by volcaniclastic products, which form the NW flank of the Stromboli volcano. Because of its steepness (> 30°) and the high amount of loose volcanic material funneled from the summit crater towards the sea, the submarine part of the SdF is prone to instability phenomena recurring at different spatial and temporal scale. Particularly, landsides with a volume of some millions of cubic meters, as the 2002 tsunamigenic landslide, can repeatedly affect the submarine slope. Based on the integration of 11 years (2002–2013) of morpho-bathymetric monitoring of the SdF with geotechnical characterization of volcaniclastic and lava flow materials, stability analyses of the subaerial and submarine slope and previous literature studies, we analyze the role of different triggering mechanisms in controlling the occurrence and size of submarine slope failures at the SdF, such as dykes intrusion as occurred in 2002 or the emplacement of a large delta as occurred in 2007.

19 pages, 15 figures, 2 tables, supplementary material https://doi.org/10.1016/j.margeo.2020.106372.-- Data availability: The datasets analysed during the current study are available from the corresponding author on reasonable request, The upper continental slope offshore Capo Vaticano (southern Tyrrhenian Sea) is characterized by a contourite depositional system with well-developed elongated sediment drifts. This system is related to a northward paleo-bottom current, similar to the present-day modified-Levantine Intermediate Water (modified-LIW) flowing from the Messina Strait. In this work, we show results from an integrated analysis of descriptive oceanography, high-resolution seismic profiles and core data (i.e., grain size, foraminiferal assemblages, tephrostratigraphy and AMS radiocarbon dating) collected from the crest and moat sectors of drift deposits. The studied succession formed since the mid Holocene, under the action of the modified-LIW and the stratigraphic architecture indicates an upslope migration of the moat and rather stable position of the crest sector. Grain-size features recorded from two sediment cores indicate the occurrence of a succession of complete bi-gradational sand-rich contourite sequences. Sandy facies were observed both as lag deposits formed in active moat channel and as coarser intervals of bi-gradational sequences forming drift deposits close to its crest. Their occurrence would highlight that upper slope environments impacted by intermediate water masses and proximal to sandy sources may represent favorable settings for accumulation of sandy sediment. The moat sector is characterized by a more complex stratigraphic record, where either moat sedimentation or lateral deposition of finer sediment occur, suggesting that further investigation is required to better understand this complex element of contourite systems. Based on available age information, some of the bi-gradational sequences probably formed during the Dark Age Cold Period, providing example of a small-scale cyclicity of contourite deposition, likely related to short-term (possibly multicentennial scale) fluctuations of the paleo modified-LIW. According to age constraints and analysis of foraminiferal assemblages, these fluctuations were likely governed by climate variations, with a weaker activity during warmer periods and faster currents during colder events, Core LGT5 was collected during the Gioia77 cruise funded by the Eurofleets2 Project. With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Stromboli is an active insular volcano located in the Southern Tyrrhenian Sea and its recent volcanic activity is mostly confined within the Sciara del Fuoco (SdF, hereafter), a 2-km wide subaerial–submarine collapse scar, which morphologically dominates the NW flank of the edifice. In August-November 2014, an effusive eruption occurred along the steep SdF slope, with multiple lava flows reaching the sea. The integration of multisensor remote sensing data, including lidar, photogrammetric, bathymetric surveys coupled with SAR amplitude images collected before and after the 2014 eruption enabled to reconstruct the dynamics of the lava flows through the main morphological changes of the whole SdF slope. Well-defined and steep-sided ridges were created by lava flows during the early stages of the eruption, when effusion rates were high, favoring the penetration into the sea of lava flows as coherent bodies. Differently, fan-shaped features were emplaced during the declining stage of the eruption or in relation to lava overflows and associated gravel flows, suggesting the prevalence of volcaniclastic breccias with respect to coherent lava flows. The estimated volume of eruptive products emplaced on the SdF slope during the 2014 eruption, accounts for about 3.7 × 106 m3, 18% of which is in the submarine setting. This figure is different with respect to the previous 2007 eruption at Stromboli, when a large lava submarine delta formed. This discrepancy can be mainly related to the different elevation of the main vents feeding lava flows during the 2007 eruption (around 400 m) and the 2014 eruption (around 650 m). Besides slope accretion, instability processes were detected both in the subaerial and submarine SdF slope. Submarine slope failure mobilized at least 6 × 105 m3 of volcaniclastic material, representing the largest instability event detected since the 2007 lava delta emplacement.

The distribution and morphological characteristics of the shelves around Salina Island have been analyzed and integrated with observations from onshore geological field studies in order to improve knowledge about its evolution, and to demonstrate how shelf width/depth can be used as proxies for reconstructing the development of the volcanic edifice. Insular shelves form essentially through marine erosion of volcanic centres during stages of reduced or inactive volcanism, and are representative of their original extension. Shelves having larger widths (commonly > 1000 m) and deeper edges (over 125 m depth) experienced wave erosion during successive cycles of sea-level fluctuations and subsidence after their formation, thus being indicative of a relatively older age of the eroded volcanic centres. Accordingly, we document offshore Salina the occurrence of presently submerged and largely dismantled volcanic centres (namely Pizzo Capo North and Fossa delle Felci South) predating the oldest subaerial products exposed on the adjacent coastal sectors. These offshore centres have subsided after their erosion and are no more documented on land. Furthermore, the finding of the largest and deepest shelf around the subaerial remnants of Pizzo di Corvo volcanic edifice allows relating it to an earlier stage of evolution of Salina, shedding light on contradictory radiometric ages on land. Narrower shelves (commonly < 1000 m) indicate a lower evolutionary maturity with respect to the larger ones; they are, in fact, formed along the sectors of the island where younger volcanic products are exposed, such as to the north and south of Monte dei Porri. The depths of the shelf edges, mostly at - 110 m (in the areas not affected by later mass-wasting), suggest that these coastal sectors were relatively stable or even slightly uplifted after erosion during Last Glacial Maximum. Moreover, several interacting factors (such as lithology of volcanic products, fetch and exposure to prevailing storms, degree of submarine erosion, relative sea level changes) have been taken into account to explain the morphological setting of the different shelf and coastal sectors of Salina. On the whole, our results show the importance of integrated field and marine studies to unravel the geological evolution of insular volcanoes and to obtain inferences on their vertical mobility.

Multibeam bathymetry, high-resolution seismic profiles and seafloor samples have been analyzed to characterize depositional and erosional dynamics recorded pro-deltaic deposits and outer shelf sediments along of a sector of the NE Sicilian margin (southern Tyrrhenian Sea). The deltaic deposits cover an area of ca. 15 km 2 in front of the Mazzarra River, and are morphologically characterized by waveforms trending overall along strike and incised cross-strike gullies of variable length. The gullies are shallow and characterized by small, coaxial erosive scours in the inner-middle shelf, whereas they become larger and deeper in the outer shelf-upper slope, in relation to the marked increase of slope gradients at the shelf break. Here, the wider gullies are characterized by a frame of crescent-shaped bedforms interpreted as cyclic steps, indicating the occurrence of sedimentary gravity flows in supercritical regime. Prodelta waveforms are widespread between − 50 and − 120 m, with wave lengths of 34–110 m and wave heights of 0.5–3 m. Morphometric characterization and spatial distribution of the waveforms suggests a main role in their genesis played by hyperpycnal flows, although we cannot discard the possible effect of internal waves or slow deformation processes (i.e., creep). Depositional and erosional features similar to those observed on the seafloor are evident in the subsurface stratigraphy, revealing the onset and growth of the Mazzarra Delta since the Last Glacial Maximum. The post-glacial sea level rise caused lateral shifts of the Mazzarra River mouth controlling migration of depositional lobes and intensity of seafloor incision and sediment reworking, ultimately resulting in the observed wavy bedforms extending from the inner shelf to the upper slope.

The SEISMOFAULTS project (www.seismofaults.it) was set up in 2016 with the general plan of exploring the seismicity of marine areas using deep seafloor observatories. The activity of the first two years (Seismofaults 2017 and 2018) consisted of the installation of a geophysical-geochemical temporary monitoring network over the Ionian Sea floor. Eleven ocean-bottom seismometers with hydrophones (OBS/H) and two seafloor geochemical-geophysical multiparametric observatories were deployed to: (1) identify seismically active faults; (2) identify potential geochemical precursors of earthquakes; and (3) understand possible cause–effect relationships between earthquakes and submarine slides. Furthermore, five gravity cores were collected from the Ionian Sea bottom and ~4082 km of geophysical acquisition, including multibeam and single channel seismic reflection data, were acquired for a total of 4970 km 2 high-resolution multibeam bathymetry. Using Niskin bottles, four water column samples were collected: two corresponding at the location of the two multiparametric observatories (i.e., along presumably-active fault zones), one corresponding at a recently discovered mud volcano, and one located above a presumably-active fault zone away from the other three sites. Preliminary results show: (1) a significant improvement in the quality and quantity of seismological records; (2) endogenous venting from presumably active faults; (3) active geofluid venting from a recently-discovered mud volcano; and (4) the correct use of most submarine devices. Preliminary results from the SEISMOFAULTS project show and confirm the potential of multidisciplinary marine studies, particularly in geologically active areas like southern Italy and the Mediterranean Sea.

River deltas are highly dynamical and valuable environments and often undergo strong natural changes and human-induced pressures that need careful observation and monitoring. However, the high dynamicity of submerged deltas makes it very hard to observe how sediment are distributed across the delta area, a crucial element in understanding their morpho-dynamic evolution. To fill this observational gap, in the last few years (2013-2016) repeated high-resolution multibeam bathymetry surveys were carried out for the first time at the Po della Pila delta, the recent-most delta lobe of the Po river. The collected bathymetric and acoustic reflectivity (backscatter), seabed samples and seismic profiler datasets provided insights on the short-term morphological and sedimentological evolution of the extremely dynamic submarine portion of the delta in the framework of the hydrodynamical, seismo-stratigraphical and environmental setting. A high variety of geomorphological features and depositional bodies at different scales were observed from the mouth bar to the prodelta slope such as the alongshore and radial bars under the effect of marine currents, gravitational-instability phenomena and collapse depressions driven by fluid expulsion. Concurrently, the analysis of the seabed reflectivity and sediment samples allowed the identification of two main classes of seafloor sediment, corresponding to dominantly sandy vs. muddy substrata. The comparison among time-lapsed, high-resolution DEMs in the time frame 2013-2016 showed that the main changes occurred on the northern side of the prodelta slope in front of the active channel: mainly as a consequence of the flood of November 2014, a new lobe-shaped fine-sediment deposit up to 4.5 m thick corresponds to a newly-added sediment volume of 1.16 Mm3. Other major morphological changes occurred in the prodelta slope, where radial depositional bars showed a net S-ward migration. Moreover, a generalized seafloor deepening was documented, accompanied by changes in seabed reflectivity with a general coarsening of the delta lobe sediment distribution from the first to the third survey. We document the morphological and sedimentological complexity and the rapidity of the geomorphological changes in the shallow reaches of the Po della Pila lobe. Given the high rates of sediment accumulation and rapid erosion related to storms and currents, this area represents as well a relevant site to study the Anthropocene short-term climate-driven variability of the coastal region including the possible interaction among human-induced changes in sediment supply, coastal erosion, alongshore sediment transport, local subsidence (both natural and anthropogenic) and submarine slope instability.

Discoveries from multibeam bathymetry and geochemical surveys performed off Zannone Island (western Pontine Archipelago, Tyrrhenian Sea) provide evidence of an undocumented hydrothermal field characterized by ongoing fluid emissions and morphologically complex giant depressions located in shallow water ( 250 m) that host pockmarks, mounds, small cones and active fluid vents, and which are interpreted as complex fluid escape features developed both through vigorous-explosive events and steady seepage. Their spatial distribution suggests that the NE-SW trending faults bounding the Ponza-Zannone structural high and the shallow fractured basement are favorable conditions for the upward migration of hydrothermal fluids. Moreover, we performed a detailed geochemical study to investigate the source of the hydrothermal fluids. The geochemical signature of the collected fluids provides information of active CO2-dominated degassing with a significant contribution of mantle volatiles, with measured 3He/4He values > 3.0 Ra that are similar to those recorded at Stromboli and Panarea volcanoes. The hydrothermal system produces volatiles that may originate from residual magma batches, similar to the Pleistocene trachytes cropping out in the SE sector of Ponza Island, that were probably intruded in the shallow crustal levels and never erupted. The discovery of the Zannone hydrothermal field updates the record of active hydrothermal areas of the Mediterranean Sea. Moreover, the recognition of several giant hydrothermal depressions characterized by a complex morphology is peculiar for the Mediterranean Sea.

The Late Quatemary architecture of the upper slope-shelf sector of the Calabro-Tyrrhenian continental margin off Capo Vaticano was reconstructed to decipher the interaction of along-slope and down-slope sedimentary processes, based on the analysis of very high-resolution single-channel seismic profiles and multibeam bathymetry. Both along-slope bottom currents and downslope gravity processes influenced the stratigraphic architecture of the margin during the last eustatic cycle, locally forming a mixed turbidite and contourite system. Along-slope processes formed elongated drifts located on the upper continental slope and outer shelf, while gravity-driven down-slope processes formed mass-transport deposits and turbidite systems with erosive channels, locally indenting the present-day shelf. Several slide events affected the elongated drifts and failure processes appear to be dominated by translational sliding that affect the upper 10-20 m of the stratigraphic record, with glide plains developed within contourite deposits. The most striking feature is the Capo Vaticano slide complex, which displays a large spatial coverage (area of about 18 km(2)), between ca - 190 m and 500 m and is composed of several intersecting slide scars and overlapping deposits. These characteristics are peculiar for the Tyrrhenian continental margins, where slide events developed in open-slope areas are usually less complex and smaller in size. This would indicate that high sedimentation rates and occurrence of contourite deposits can represent a preconditioning factor for medium-large scale slope instability on the Tyrrhenian margins. (C) 2016 Elsevier B.V. All rights reserved.

In this study, we present a framework for seagrass habitat mapping in shallow (5&ndash, 50 m) and very shallow water (0&ndash, 5 m) by combining acoustic, optical data and Object-based Image classification. The combination of satellite multispectral images-acquired from 2017 to 2019, together with Unmanned Aerial Vehicle (UAV) photomosaic maps, high-resolution multibeam bathymetry/backscatter and underwater photogrammetry data, provided insights on the short-term characterization and distribution of Posidonia oceanica (L.) Delile, 1813 meadows in the Calabrian Tyrrhenian Sea. We used a supervised Object-based Image Analysis (OBIA) processing and classification technique to create a high-resolution thematic distribution map of P. oceanica meadows from multibeam bathymetry, backscatter data, drone photogrammetry and multispectral images that can be used as a model for classification of marine and coastal areas. As a part of this work, within the SIC CARLIT project, a field application was carried out in a Site of Community Importance (SCI) on Cirella Island in Calabria (Italy), different multiscale mapping techniques have been performed and integrated: the optical and acoustic data were processed and classified by different OBIA algorithms, i.e., k-Nearest Neighbors&rsquo, algorithm (k-NN), Random Tree algorithm (RT) and Decision Tree algorithm (DT). These acoustic and optical data combinations were shown to be a reliable tool to obtain high-resolution thematic maps for the preliminary characterization of seagrass habitats. These thematic maps can be used for time-lapse comparisons aimed to quantify changes in seabed coverage, such as those caused by anthropogenic impacts (e.g., trawl fishing activities and boat anchoring) to assess the blue carbon sinks and might be useful for future seagrass habitats conservation strategies.

In the Mediterranean Sea, coralline algae assemblages (i.e. rhodolith beds and coralligenous assemblages) are considered biodiversity hotspots comparable to tropical reefs. However, information regarding their environmental distribution is still poor. In this view, relevant international actions have been adopted by the European Union to fill this gap. This work represents one of a few cases of predictive (fine-scale) habitats distribution map obtained through an integrated semi-automatic approach based on bathymetry, backscatter, seismic profiles, video, and sampling data. The used method has permitted the identification of nine morphological zones, four backscatter facies, and four benthic habitats distributed on the Zannone seafloor (western Pontine Archipelago; Tyrrhenian Sea). In particular, the finding of widespread sensitive habitats (i.e. coralligenous assemblages and rhodolith beds) reveals as the marine area off the western Pontine Archipelago (Tyrrhenian Sea) is highly suitable for their development (distance from the mainland, lack of river mouths), confirming the relevant ecological value of the Zannone area. Therefore, such information constitutes an update to the Mediterranean habitats distribution inventory, highlighting the need for the application of protection actions possibly targeted in the establishment of a Marine Protected Area.

A mono-specific population of Isidella elongata in the Ventotene Basin (Pontine Islands, western Mediterranean Sea) was recently revealed by ROV survey. This vulnerable marine community was found on top of a 3.6 km long morphological high, in water depths between 510 and 560 m. Side scan sonar data showed the presence of several trawl marks suggesting a high anthropogenic impact of the study area. Furthermore, multibeam and high-resolution seismic data revealed the presence of widespread pockmarks, indicating occurrence of fluids in the sub-seafloor.

The recent high-resolution multibeam bathymetry surveys around Lipari Island allowed to evidence several submarine canyons, whose head often cut back up to very shallow water and at a few tens of meters far from the coast. These canyons are mainly located in the eastern and southern side of the island and are characterized by an ongoing retrogressive (landward) erosion, that also controlled the shape and the evolution of the coastline. The canyon heads are formed by minor slide scars. By coupling slide scar morphometry and simple numerical model we have been able to roughly estimate the potential tsunami wave amplitudes generated by related slope failures. Moreover, the retrogressive erosion of canyon heads can be claimed as a cause of the enhanced subsidence reported in the last few thousand years in the eastern part of Lipari, where the main villages are located. Based on these evidence, we propose a first assessment of the coastal hazard due to marine retrogressive activity in the largest and most densely populated island of the Aeolian Archipelago.

The integrated analysis of high-resolution multibeam bathymetry and single-channel seismic profiles around Salina Island allowed us to characterize the stratigraphic architecture of the insular shelf. The shelf is formed by a gently-sloping erosive surface carved on the volcanic bedrock, mostly covered by sediments organized in a suite of terraced bodies, i.e. submarine depositional terraces. Based on their position on the shelf, depth range of their edge and inner geometry, different orders of terraces can be distinguished. The shallowest terrace (near-shore terrace) is a sedimentary prograding wedge, whose formation can be associated to the downward transport of sediments from the surf zone and shoreface during stormy conditions. According to the range depth of the terrace edge (i.e., 10–25 m, compatible with the estimated present-day, local storm-wave base level in the central and western Mediterranean), the formation of this wedge can be attributed to the present-day highstand. By assuming a similar genesis for the deeper terraces, mid-shelf terraces having the edge at depths of 40–50 m and 70–80 m can be attributed to the late and early stages of the Post-LGM transgression, respectively. Finally, the deepest terrace (shelf-edge terrace) has the edge at depths of 130–160 m, being thus referable to the lowstand occurred at ca. 20 ka. Based on the variability of edge depth in the different sectors, we also show how lowstand terraces can be used to provide insights on the recent vertical movements that affected Salina edifice in the last 20 ka, highlighting more generally their possible use for neo-tectonic studies elsewhere. Moreover, being these terraces associated to different paleo-sea levels, they can be used to constrain the relative age of the different erosive stages affecting shallow-water sectors.

The collection of high-resolution multibeam bathymetry, single-channel seismic profiles, TOBI side scan sonar data, and gravity cores allowed the characterization of the main morpho-sedimentary processes acting along the lower reach of the shelf-indenting Gioia-Mesima canyon-channel system (GMS) and the surrounding continental slope (southern Tyrrhenian Sea). This last area, developing across a depth range of 1000–1700 m, shows a complex morphology due to the interaction between downslope gravitative processes (mainly turbidite sheet flows) and abrupt changes in slope gradients related to tectonically-controlled scarps. Particularly, several erosive-depositional features (levee deposits, sediment undulations, channels) have been related to overflow processes from the northern flank of the GMS, although the lower reach of the GMS is characterized by strong entrenchment (canyon height ranging from 120 to 270 m) and low sinuosity. Morphological and seismic stratigraphy data indicate that the distribution and dimension of these features vary in response both to the proximity to the external levee of the GMS and to the topographic gradient of the lower continental slope. Particularly, we were able to discriminate between a gently sloping sector (on average 1.5°) dominated by sedimentary bypass of the turbidity currents and a steeper sector (about 3°), where the erosional capability of these currents seems to increase. Indeed, three channels, 4,3–6,5 km long and up to 20 m deep, incise this steeper sector, running parallel to each other at a distance of 1250–1500 m. To support the capability of overbanking flow in producing these channels, we used a physical model for the ignition of turbidity currents that provides realistic values for the ignitive state of the overbanking turbidity flows. More generally, the methodological approach used in this study may be useful to provide constraints on the genesis and evolution of erosive-depositional features in other tectonically-controlled margins, where sedimentary gravity flows interact with an uneven morphology.

Recent underwater archaeological surveys recovered hundreds of flint artefacts between depths of 18 and 21 m at cala tramontana, a small bay located in the eastern part of pantelleria island. Most of the flint artefactsindicate debitage, and are characterized by cores and flakes without any specific morphology. Different lithic tools were also identified, such as fragments of blades, truncations, end-scrapers, points and crested blades. Aninitial hypothesis is that this lithic industry represents the oldest traces of human visitation to the island,possibly related to the exploitation of the nearby obsidian source, and favoured because of the sheltered coastalconfiguration of cala tramontana and cala levante with respect to the dominant winds and related storms. However,the present-day coastal setting in the bay is rather inhospitable, with high cliffs and difficult marine access.in contrast, palaeo-landscape reconstructions by means of high-resolution multibeam bathymetry reveal thepossible presence of a small palaeobeach in the inner part of the bay when the sea level was 15 m lower than at present.By comparing this palaeo-sea level with the eustatic curve (and by excluding possible vertical movements), we roughly estimate an age of the lithic industry of 9.6-7.7 cal ka BP © The geological society of london 2016.

Archaeological and instrumental data indicate that the southern sector of the volcanic island of Lipari has been subsiding for the last 2100 years due to isostatic and tectonic factors, at variable rates of up to ~11 mm/yr. Based on this data, a detailed marine flooding scenario for 2100 A.D. is provided for the bay of Marina Lunga in the eastern part of the island from (i) an ultra-high-resolution Digital Terrain and Marine Model (DTMM) generated from multibeam bathymetry (MB) and Unmanned Aerial Vehicles (UAV), (ii) the rate of land subsidence from GPS data and (iii) the regional sea-level projections of the International Panel on Climate Change (IPCC). When land subsidence is considered, the upper bound of sea-level rise is estimated at 1.36 m and 1.60 m for RCP4.5 and RCP8.5 climate change scenarios, respectively. Here, we show the expected impact of marine flooding at Lipari for the next 85 years and discuss the hazard implications for the population living along the shore. This article is protected by copyright. All rights reserved.

New high-resolution geophysical data collected along the eastern margin of the Tyrrhenian back-arc basin, in the Pontine Islands area, reveal a ~NW-SE elongated morphological high, the Ventotene Volcanic Ridge (VR), located on the northern edge of the Ventotene Basin. High-resolution multibeam bathymetry, combined with magnetic data, multi- and single-channel seismic profiles, and ROV dives, suggest that VR results from aggregation of a series of volcanic edifices. The summit of these volcanoes is flat and occurs at about 170 m water depth. Given their depths, we propose that flat morphologies were probably caused by surf erosion during Quaternary glacial sea level lowstands. Seismic stratigraphy together with magnetic data suggest that the volcanic activity in this area is older than 190-130 ka age and may be coeval with that of Ventotene Island (Middle Pleistocene). The submarine volcanoes, located 25 km north of Ventotene, are part of a ~E-W regional volcanic alignment and extend the Pontine volcanism landward toward the Gaeta bay. Integration of structural data from multichannel seismic profiles in this sector of the eastern Tyrrhenian margin indicates that several normal and/or transtensional faults, striking WNW-ESE, NNW-SSE, and NE-SW, offset the basement and form alternating structural highs and depressions filled by thick, mostly undeformed, sedimentary units. Arc-related magmatism is widespread in the study area, where the VR is placed at the hangingwall of the west-directed Apennines subduction zone, which is undergoing tensional and transtensional tectonics. Bathymetric and topographic evidence shows that VR lies in between a major NE-SW trending escarpment east of Ponza and a NE-SW trending graben southwest of the Roccamonfina volcano, a NE-SW transfer zone that accommodate the extension along this segmented portion of the margin. This suggests that the interaction between NE-SW and NW-SE trending fault systems acts as a structural control on location of eruptive centers, given that main volcanic edifices develop along the NW-SE direction, compatible with the extensional setting of the Tyrrhenian basin.

Small-scale crescent-shaped bedforms were identified within flat-bottomed channelized features carving the submarine volcanic flanks of the Stromboli and Salina edifices. The bedforms are downslope-asymmetric, with a sub-horizontal stoss side and a steep lee side. They have a wavelength of tens of metres and a wave height of metres, and their crest-lines are roughly perpendicular to the maximum slope. Based on their size, texture and similarities to other bedforms, they can be interpreted as cyclic steps, i.e. a class of upslope-migrating turbidite sediment waves. Although their genesis must be similar, some differences are observed between the two cases. At Stromboli, repeated multibeam surveys at an 11-year scale showed a significant upslope migration of the bedforms because they lie on the bottom of a channel connected to active coastal dynamics, whose headwall is located at a few metres depth. By contrast, the surveys showed no significant morphological variations at Salina, where the bedforms are larger than at Stromboli and the channel headwall is located at about -100 m, suggesting that these feature are mostly inactive at present.

High-resolution multibeam bathymetry have revealed coaxial trains of crescent-shaped bedforms within the heads of channelized features lying in shallow-water sectors along the tectonically-controlled Calabrian Margin. These bedforms have wavelengths of tens or a few hundreds of metres and wave heights of a few metres, and their crest-lines trend perpendicular to the maximum slope gradients. Repeated multibeam surveys carried out in 2007, 2008, 2012 and 2013 showed a rapid and significant morphological evolution of the channel’s floors, with the generation or upslope migration of the bedforms. Based on their size, upslope migration and similarities to crescent-shaped bedforms recognized in other active canyon heads, these features can be interpreted as cyclic steps. The bedforms are, in fact, formed or modified by frequent slope failures and related sedimentary flows, whose occurrence is favoured by the concurrent presence of several predisposing and triggering mechanisms, such as a high sedimentation rate due to a steep coastal creek, severe storms and seismic events.

The analysis of high resolution morpho&ndash, bathymetric data on the Calabro Tyrrhenian continental margin (Southern Italy) enabled us to identify several morphological features originated by mass&ndash, wasting processes, including shallow gullies, shelf&ndash, indenting canyons and landslides. Specifically, we focus our attention on submarine landslides occurring from the coast down to &minus, 1700 m and affecting variable areas from thousands of square meters up to few tens of square kilometers. These landslides also show a large variability of geomorphic features which seems strictly related to the physiographic/morphological domains where the landslide formed. Tectonically&ndash, controlled scarps and canyon flanks are typically characterized by several coalescent and nested landslides, with diameters ranging from hundreds to a few thousands of meters. Canyon headwalls are commonly characterized by a cauliflower shape due to an array of small (diameters of tens of meters) and coalescent scars. In all these sectors, disintegrative&ndash, like landslides dominate and are generally characterized by a marked retrogressive evolution, as demonstrated by their morphology and comparison of repeated bathymetric surveys at the canyon headwall. Only in the lower part of tectonically&ndash, controlled scarps, a few cohesive&ndash, like and isolated landslides are present, indicating the main role of slope gradients and height drop in controlling the post&ndash, failure behavior of the mobilized material. Open slopes are generally characterized by large&ndash, scale (diameters of thousands of meters) and isolated scars, with associated landslide deposits. A peculiar case is represented by the Capo Vaticano Scar Complex that affected an area of about 18 km2 and is characterized by an impressive variability of landslide morphologies, varying also at short distance. The large extent and variability of such scar complex are thought to be associated with the occurrence of a mixed contouritic&ndash, turbidite system. By integrating the high&ndash, resolution morpho&ndash, bathymetric dataset with the results of previous studies, we discuss the main factors controlling the variability in size and morphology of submarine landslides developed in a tectonically&ndash, controlled setting and provide preliminary considerations on their potential geohazard in a densely populated coastal area.

Lipari island belongs to the Aeolian archipelago, located in the Southern Tyrrhenian Sea (Italy), which is one of the most active volcanic areas of the Mediterranean basin. Although this region has been settled since prehistory, only during Roman times were coastal installations built in these islands. In this study, we present and discuss data on the relative sea level change estimated from a submerged pier of Roman age dated 2100 ± 100 BP. This structure, about 140 × 60 m, is located along the coast of Marina Lunga, corresponding to the present location of the main harbor of Lipari island. This pier, which was accidentally discovered in 2008 during preliminary excavations for the construction of a new pier, is a valuable indicator of relative sea level changes and vertical land movements. Its top surface is presently located at −9.1 ± 0.05 m, while the foundations at the outer end of the pier are at −11.6 ± 0.05 m, above a shoreline placed at −13.0 ± 0.05 m. We studied this site through direct archaeological investigations and ultra-high resolution multibeam bathymetry. The current submergence of this pier can be explained by the cumulative effect of the relative sea level changes caused by the regional glacio-hydro-isostatic signal, active since the end of the last glacial maximum, and the local volcano-tectonic land subsidence. From our investigations, a relative sea level change at 12.3 ± 0.7 m with a subsidence rate at 5.79 ± 0.01 mm y −1 and an average value of volcano-tectonic contribution at 5.17 ± 0.01 m y −1 for the last 2100 ± 100 years BP, is estimated from comparison against the latest predicted sea level model for the Southern Tyrrhenian Sea. These rates of relative sea level change led to the disuse of the harbor after around the fourth century AD, in agreement with archaeological interpretations. Our results provide new insights on the recent evolution of this active volcanic area.

Dense aggregations of antipatharian corals have been discovered by means of remotely operated vehicle (ROV) photo-imaging off the western Pontine Islands (Central-Tyrrhenian Sea, Italy). These black coral assemblages are mainly composed of Parantipathes larix and Leiopathes glaberrima . This discovery constitutes an update of their habitat distribution for the Mediterranean Sea and is relevant for the development of focused protection measures for the study area.