The Sciara del Fuoco (SdF) collapse scar at Stromboli is an active volcanic area affected by rapid morphological changes due to explosive/effusive eruptions and mass-wasting processes. The aim of this paper is to demonstrate the importance of an integrated analysis of multi-temporal remote sensing (photogrammetry, COSMO-SkyMed Synthetic Aperture Radar amplitude image) and marine geophysical data (multibeam and side scan sonar data) to characterize the main morphological, textural, and volumetric changes that occurred along the SdF slope in the 2020-2021 period. The analysis showed the marked erosive potential of the 19 May 2021 pyroclastic density current generated by a crater rim collapse, which mobilized a minimum volume of 44,000 m in the upper Sciara del Fuoco slope and eroded 350,000-400,000 m of material just considering the shallow-water setting. The analysis allowed us also to constrain the main factors controlling the emplacement of different lava flows and overflows during the monitored period. Despite the morphological continuity between the subaerial and submarine slope, textural variations in the SdF primarily depend on different processes and characteristics of the subaerial slope, the coastal area, the nearshore, and "deeper" marine areas.

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 <20 m, a few hundred metres from the coast, acting as a main collector for sediments transported by hyperpycnal flows and/or littoral drift. These canyons mostly have a V-shaped cross-section and are characterized by a strong axial incision, where a network of dendritic gullies carving the canyon flanks converges. The second type of canyon occurs where the shelf is wider, hindering the direct connection between the subaerial and submarine drainage system. This setting exhibits canyon heads mostly confined to the shelf break, characterized by a weaker axial incision of the canyon and U-shaped cross-section. A total of 280 landslide scars are recognized in the study area and these are divided into three groups according to their morphology and location. A morphometric analysis of these scars is performed to investigate which parameters might be key factors in controlling instability processes and how they correlate with each other. We also try to assess the possible tsunamigenic potential associated with these landslide events by coupling the morphometric analysis with semi-empirical relationships available in the literature.

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.

In this study, we present a framework for seagrass habitat mapping in shallow (5-50 m) and very shallow water (0-5 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' 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 course of three years, the CNR-ISMAR of Naples carried out the surveys ("Lampedusa 2015", "Linosa 2016" and "BioGeoLin 2017") with the aim of studying the seabed of the insular shelf of Lampedusa, Linosa and Lampione, the three islands belonging to the Pelagie Archipelago. A common feature of all three surveys was the use of the multibeam Teledyne Reson SeaBat 7125 400 kHz (Innangi et al., 2018; Innangi et al., 2019), providing sub-centimetric resolution in the bathymetric data at that depth range between 5 to 180 m. Furthermore, the vessels employed were equipped with the same auxiliary instruments, i.e. an Oministar DGPS (for position data), an IxSea Octans 3000 (for attitude data), and a Valeport mini-SVS sound velocity probe installed near the transducer (for beam steering). For all surveys, the snippet data was logged (as backscatter information) with the same Absorption and Spread acquisition parameters. Also the data processing was the same, e.g. the snippet data was processed using FMGeocoder Toolbox (FMGT) in Fledermaus 7.6 version (QPS, 2016) to produce mosaic images with the same amplitude range, from -60 dB (lighter tones, corresponding to low backscatter) to -25 dB (dark grey tones, corresponding to high backscatter). Furthermore, ground-truth information, in the form of video-investigation (for all islands) and grab samples (only for Linosa and Lampione), were collected during the surveys. These characteristics made it possible to analyse all islands with RSOBIA (Remote Sensing Object Based Image Analysis) with the integrated information derived from backscatter data and bathy-morphological features, validated by ground-truth data (Innangi et al., 2018; Innangi et al., 2019) to produce three seabed maps, including seagrass distribution and benthoscape classification (according to Lacharité et al., 2017), and comparable to each other. Finally, it must be emphasized that the maps provided the first indication of the occurrence of rhodolith and maërl habitats at Lampione and Linosa, which are among the most important ecosystems in the Mediterranean Sea, while for Lampedusa further ground-truth data are necessary to better characterize the acoustic facies pattern of the island (Innangi et al., 2018; Innangi et al., 2019)

Linosa Island represents the emergent tip of a mostly submarine volcanic edifice, with at least 96% of its areal extent lying below sea level. Its morphology is the result of volcanic subaerial activity dated from ~1.06 Ma to 0.5 Ma (Rossi et al., 1996). Until now, the scant knowledge on its submarine extension led to consider this volcanic edifice as extinct. Marine geological surveys carried out by ISMAR CNR of Naples in 2016 and 2017 allowed to reconstruct the submarine portions of Linosa down to a depth of 1000 m, indicating a much wider submarine extension than expected. The new multibeam data, integrated by seismic profiles and ROV inspections, provided new insights on the evolution and biological colonization of this little-explored volcanic edifice. Overall, it extends for about 20 km in the NW-SE direction, evidencing a tectonic control from the main structural system of the Sicily Channel, as already suggested for the subaerial portions (Rossi et al., 1996). Along the same direction, also a marked tectonic lineament and a field of pockmarks can be observed at the base of the W/SW flanks, respectively. The shallow-water SE and NW portions of the volcanic edifice show wide insular shelves, giving evidence on the original extent of the early eruptive centres at the time of emersion stage, prior to their erosion during late-Quaternary sea-level fluctuations (Romagnoli, 2004). These areas are the seat of a very rich ecosystem with a pristine coralligenous habitat. Where insular shelves are lacking, canyons and gullies develop with a radial pattern from shallow water down to the base of the submarine flanks. A number of volcanic features such as lava fields, lava flows and are recognized on the submarine flanks, which appear punctuated by several eruptive centres. A specific morphometric investigation of the volcanic cones mapped on the Linosa submarine flanks was carried out, pointing out a strong similarity with the Pantelleria volcano, especially for what regards the distribution and morphometric characteristics of eruptive cones occurring in the submarine portions (Calarco et al. 2011). The study of the submarine extension of Linosa suggests that the growth and evolution of the volcanic edifice has likely been more complex than what inferred from its subaerial volcanism, and gives new insights on the development of volcanism in the Sicily Channel and on related potential hazard.

In this work, the seabed mapping of the shallow-water areas of Lampedusa, Lampione and Linosa, belonging to the "Pelagie Islands" Marine Protected Area, is presented. Three surveys were carried out (namely "Lampedusa2015", "Linosa2016" and "BioGeoLin") to collect bathymetric and acoustic backscatter data through the use of a Reson SeaBat 7125 high-resolution multibeam system. Ground-truth data, in the form of grab samples and diver video-observations, were also collected during the surveys. Sediment samples were analyzed for grain size, while video images were analyzed and described revealing the acoustic seabed and other bio-physical characteristics. Three seabed classification maps, including sediment types and seagrass distribution, were produced using Remote Sensing Object Based Image Analysis by integrating information derived from backscatter data and bathy-morphological features, validated by ground-truth data. The seabed maps, including sediment types and habitat distribution, contribute to the knowledge of the peculiar marine ecosystem observed at the islands.

The collection of high-resolution multibeam bathymetry off the tectonically controlled Tyrrhenian Calabrian margin (southern Tyrrhenian Sea) allowed us to recognize several mass-wasting processes, including shelf-indenting canyons and several landslide scars ranging over different spatial scales. In this paper, we aim to characterize two large submarine landslides (S1 and S2) affecting an area of c. 7 and 14 km2, respectively; both scars occur within water depths of 700-1000 m on slope gradients of 1.5-3°. S1 is interpreted as a disintegrative landslide, because most parts of the related landslide deposits were evacuated from the scar and are not recognizable on the present-day bathymetry, whereas the landslide deposits of S2 are well-preserved and mostly confined within the scar, indicating a different post-failure evolution. Based on the integration of multibeam bathymetry and single-channel seismic profiles, both the landslides are interpreted as translational failures, whereas their different post-failure behaviour has been associated with differences in material properties (inferred by headscarp morphology), depth of their failure plane and frontal confinement. We also suggest that thick contourite deposits recognized in the area may represent an important preconditioning factor for the development of these landslides, similarly to that observed in the nearby Capo Vaticano scar complex.

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 morphology of scour holes at tidal channel confluences was investigated through high-resolution acoustic mapping of the channel network in the Venice Lagoon (Italy). Our investigation identified 29 confluence scours ranging in depth from 7 to 26m and characterized by different confluence geometry and scour properties. Scours were found at the confluence of two or more channels, having equal or unequal bed heights and a diverse confluence planform geometry. The main morphological characteristics of the scours were compared to literature data from fluvial environments. Like in rivers, the scour depth tends to increase with the angle of the confluence. Moreover, the maximum depth of the confluence scours in the Venice Lagoon is positively correlated with the tidal prism of the channels joining the confluence. The investigation of the seafloor features in the scour holes highlighted that, generally, small- and medium-scale bedforms are present on the gentle slope. The scours' seafloor roughness indicated that in tidal channels both ebb and flood flows combine in shaping the confluence morphology. In addition, the analysis of historical bathymetric datasets dating back to the 1800s allowed us to analyze the morphological evolution of two of these erosive features. Our findings revealed the century-scale morphological dynamics of scour holes, as a consequence of changes in the flow regime.

We report the geomorphological features of the continental shelf of the Gulf of Naples along the submarine slopes of the Somma-Vesuvius volcanic complex. This area is characterized by seafloor morphologies that are related to mantle degassing. Significant phenomena associated with this process occur. Doming of the seafloor has been detected in the area of Banco della Montagna, whereas a hole-like morphology has formed at Bocca dei Pescatori, likely as a result of a phreatic explosion. Outcropping or partially submerged volcanic bodies are also present as well as two main debris avalanche deposits arising from the main Somma-Vesuvius edifice. A large area characterized by an overall concave external profile and a global sediment wave morphology covers most of the southwestern area of the volcano.

Lipari is the largest and most populated island of the active Aeolian volcanic archipelago (Southern Tyrrhenian sea). In this study we show and discuss data on the relative sea level change inferred from historical and archaeological indicators located along the eastern coast of Lipari. In particular we focus on a ? 200x60 m of size submerged pier of Roman age dated at 2000±100 years BP, located at Marina Lunga, that correspond to the location of the modern harbor of Lipari. This structure is a valuable indicator of relative sea level change and vertical land movements, being presently located between 9 and 13 m below sea level. Global Positioning System (GPS) data collected in the last 18 years also suggest that land subsidence is still continuing in this region. From our investigations, a mean subsidence rate exceeding ? 6±0.3 mm/yr-1 is estimated, with a volcanotectonic contribution of ? 5±0.3 mm/yr-1 for the last 2 ka BP, as inferred from the comparison against the latest sea level prediction for the Southern Tyrrhenian Sea. Based on i) Digital Terrain and Marine Models realized through the merging of ultra-high resolution multibeam data and aerial photogrammetric surveys realized using Unmanned Aerial Vehicles, ii) current rates of land subsidence estimated both from 18 years of GPS data, iii) the submerged roman pier and flooded buildings built during the last three centuries and iv) current and IPCC predicted rates of sea level rise, a flooding scenario is provided for the year 2100. The upper and lower limiting values of relative sea level rise are estimated at 1.68 m and 1.21 m, for the maximum and minimum 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.

Newly collected multibeam and seismic data on the intra-slope Palmarola ridge show widespread pockmarks and landslide-related morphologies along its flanks. In detail, two main types of slope failures were identified: disintegrative-like and cohesive like landslides. The first type is characterized by a complex of small, nested scars affecting the steep and tectonically-controlled eastern flank of the ridge, suggesting a genesis related to retrogressive processes. The cohesive landslides affect the northern flank of the ridge and are characterized by larger scars, where material was not completely evacuated, and well-defined debris deposits at their base, with the development of pressure ridges. Tectonic activity and slope gradients represent the main controlling factors for the develop- ment of instabilities; moreover, we noted a relationship between pockmarks and landslide scars.

High-resolution multibeam bathymetry was recently collected around Lipari, the largest and most densely populated island of the Aeolian Archipelago (Southern Tyrrhenian Sea). The data were acquired within the context of marine geological studies performed in the area over the last 10 years. We present the first detailed morphological map of the Lipari offshore at 1:100,000 scale (Main Map). A rugged morphology characterizes the submarine portions of Lipari volcano, reflecting both volcanic and erosive-depositional processes. The volcanic features include cones, lava flows and bedrock outcrops. Erosive-depositional features include an insular shelf topped by submarine depositional terraces related to Late-Quaternary sea-level fluctuations, as well as landslide scars, channelized features, fan-shaped deposits and wavy bedforms. The different distribution of volcanic and erosive-depositional features on the various sectors of Lipari is mainly related to the older age of the western flank with respect to the eastern one. The map also provides insights for a first marine geohazard assessment of this active volcanic area.

High-resolution morpho-bathymetric data at 1:200,000 scale obtained during the FAIVI cruise (2011) and the resulting geomorphologic map of the Terceira island offshore area (central Azores, Portugal) are presented for the first time. The uneven morphology around Terceira is primarily related to volcanic features, such as linear and cone-shaped eruptive centres and lava flows. Such features are mostly concentrated on volcanic ridges and are aligned along preferential axes, suggesting a strong interaction between tectonics and volcanic processes. The occurrence of active tectonics is also demonstrated by systems of faults cutting the seafloor to the north, east and south of the island. Mapped erosive-depositional features include an insular shelf located at , 150 m water depth (wd), small landslide headwalls, erosive scarps, channelized features and crescent-shaped bedforms. The presented map may represent the base for a first-order geo-hazard assessment.

The Gulf of Cadiz, off SW Iberia and the NW Moroccan margin, straddles the cryptic plate boundary between Africa and Eurasia, a region where the orogenic Alpine compressive deformation in the continental collision zone passes laterally to the west to strike-slip deformation. A set of new multibeam bathymetry, multi-channel and single-channel seismic data presented here image the main morphological features of tectonic origin of a significant part of the Gulf of Cadiz from the continental shelf to the abyssal plain. These morphotectonic features are shown to result from the reactivation of deeply rooted faults that changed their kinematics from the early Mesozoic rifting, through the Late Cretaceous-Paleogene collision, to the Pliocene-Quaternary thrusting and wrenching. The old faults control deep incised, more than 100 km long canyons and valleys. Several effects of neotectonics on deep water seabed are shown. These include: i) the complex morphology caused by wrenching on the 230 km long WNW-ESE faults that produced en echelon folds on the sediments; ii) the formation of up to 5 km wide crescent shaped scours at roughly 4 km water depth by reactivation of thrusts; iii) 10 km long creep folds on the continental slope: and iv) the formation of landslides on active fault escarpments. The present day deformation is partitioned on NE-SW thrusts and WNW-ESE to W-E strike-slip faults and is propagating northwards on N-S trending thrusts along the West Iberia Margin from 35.5 degrees N to 38 degrees N, which should be considered for seismic hazard. (C) 2009 Elsevier B.V. All rights reserved.

The catastrophic rupture of the North Anatolian Fault east of the Marmara Sea on 17 August 1999 highlighted a need for mapping the underwater extension of that continental transform. A new bathymetric map of Izmit Gulf indicates that the fault follows the axis of the gulf with a few minor bends. Submerged shorelines and shelf breaks that formed during the Last Glacial Maximum provide markers to quantify vertical deformation. Variable tilting of these horizons reveals that vertical deformation is highest just south of the fault. A correlation between vertical deformation of the southern fault block and distance to fault bends can be accounted for by a fault dipping steeply to the south. Hence subsidence (uplift) of the southern, hanging wall block would be expected where the fault strikes at a slightly transtensional (transpressional) orientation to relative plate motion. Subsidence reaches about 8 mm/yr west of the town of Golcuk and might be accommodated in 1–2 m subsidence events during large earthquakes. That scenario is compatible with the tsunami runups and the coseismic subsidence of the southern shore that occurred in 1999. Seafloor morphology also suggests that earthquakes are accompanied by widespread gas and fluid release. The periphery of the deepest basin displays a hummocky texture diagnostic of sediment fluidization, and mud volcanoes occur west of Hersek peninsula that might be activated by earthquakes. Finally, the backscatter imagery reveals a series of lineaments midway through the gulf that are interpreted as products of the 1999 surface rupture. The seafloor is undisturbed farther west, suggesting that surface slip decreased to an insignificant level beyond Hersek. Possibly, the stress shadow from the 10 July 1894 earthquake, which was felt strongly along the western Izmit Gulf, contributed to arrest the 1999 surface rupture.

An extensive, high-resolution bathymetric survey has recently been carried out, portraying the continental shelf-slope system of the Campania Region, in southern Italy (Eastern Tyrrhenian Sea). The relative bathymetric data were acquired between 1997 and 2002, using multibeam systems with an average vertical resolution of < 0.25 % water depth and a position accuracy of < 10 m. The survey data were successively merged with a Digital Terrain Model (DTM) created from topographic maps of the onshore coastal area and islands of theNaples Bay, to produce a Digital Elevation Model (DEM) based on a homogeneous grid with cell-spacing of 20 m. The shaded-relief, colour scale map of the Naples Bay presented in this study provides new, detailed information on the morphology of the coastal Campania Region. This continental margin displays evidence of the interplay between tectonics and volcanism and their interference with sedimentary processes during the latest Neogene and Quaternary. The major morphological features revealed by the 3D digital maps are: 1) the system of marine canyons (Dohrn and Magnaghi) that cut the continental slope at a depth between 250 m and 1100 m; 2) the funnelshaped marine slope system of the Ischia volcanic structure; 3) the onshore-offshore volcanic field of the Campi Flegrei; 4) the rugged seafloor area (of a diameter of ca 2 km) off the town of Naples (Banco della Montagna), caused by active uplift of small-scale volcaniclastic diapirs (pyroclastic lumps); and 5) the debris-flow/avalanche deposits on the inner continental shelf of the Eastern Bay of Naples, that evolved from the pyroclastic products of the Vesuvius