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The investigation of submarine volcanoes and the tsunamigenic potential of possible movements on their flanks is arduous. In most cases, the lack of specific information about the eruptions’ history and their consequences does not allow a comprehensive analysis in terms of hazard. Nevertheless, useful clues on the possible occurrence of mass movements on seamounts can be obtained from a series of research fields. These account for morphological studies, observations of hydrothermal activity, collection of geophysical data (for example, detailed DEM, seismic profiles, magnetic data), etc. In this context, this study presents new bathymetric data of the Vavilov submarine volcano (Tyrrhenian Sea, Italy) and a detailed morphological analysis of the structure. The latter allows the identification of zones potentially prone to mass movements and the development of numerical scenarios to investigate the tsunami potential associated to these movements on the Vavilov flanks. Results prove that the waves generated by the mass displacements in the proposed scenarios (involving sliding volumes between 0.32 km3 and 1.7 km3) reach maximum values in the order of centimetres, not considering dispersive effects. Eventually, a scenario involving the partial collapse of the west flank of the Vavilov Seamount is simulated, although the occurrence of such an event in the past is still debated due to the uncertainties related to the origin and development of the volcano dome. In this scenario, water elevation as high as 10 m are found in large portions of the Tyrrhenian coasts: waves are large enough to emplace sizeable tsunami deposits onshore, that could have been preserved until today in some specific stretches of the coast and could be detected by a finalised geological search. This study belongs to a series of works devoted to the submarine structures of the Tyrrhenian Sea aiming to disclose the tsunamigenic potential of submarine mass movements on their flanks.

Endometriosis is defined as the presence of endometrial tissue outside the uterine cavity. It is a common finding in premenopausal women and commonly affects the gastrointestinal tract, especially the rectosigmoid tract. Small bowel involvement is rare and usually asymptomatic making diagnosis difficult. Here we report an uncommon case of exophytic ileal endometriosis surgically treated. Detailed pre-operative counselling on the risk of ileal surgery should always be considered in all cases with endometriosis requiring surgery. We also present a review of the literature regarding the clinical presentation, diagnosis, and treatment of this challenging condition.

Objectives: Deep infiltrating endometriosis is associated with chronic pelvic pain, dyspareunia, and pelvic floor muscle hypertone. The primary aim of the study was to evaluate the effects of pelvic floor physiotherapy on changes in the area of levator ani muscle hiatus under Valsalva maneuver assessed with transperineal ultrasound in women with deep infiltrating endometriosis suffering from superficial dyspareunia. Methods: In this randomized controlled trial, 34 nulliparous women diagnosed with deep infiltrating endometriosis and associated superficial dyspareunia were enrolled. After an initial clinical examination, evaluation of pain symptoms using Numerical Rating Scale and 3D/4D transperineal ultrasound, eligible women were randomly assigned (1:1) to no intervention (control group, 17 women) or treatment with five individual sessions of pelvic floor physiotherapy (study group, 17 women). Four months after the first examination, all women underwent a second evaluation of pain symptoms and transperineal ultrasound. During both ultrasound examinations, the levator hiatal area was measured at rest, upon maximum pelvic floor muscle contraction and maximum Valsalva maneuver. The primary outcome measure was the change in the levator hiatal area at maximum Valsalva maneuver between the two examinations in the two groups. Results: Thirty women completed the study and were included in the analysis: 17 in the study group and 13 in the control group. The percentage change in levator hiatal area at maximum Valsalva maneuver between the two examinations was higher in the study group than in the control group (20.0±24.8% vs. -0.5±3.3%, P=0.02). After treatment, the change in the Numerical Rating Scale score of superficial dyspareunia was higher in the study group than in the control group (median [interquartile range] -3 [-4,-2] vs. 0 [0,0], P

New multichannel seismic reflection profiles were acquired to unravel the structure of a portion of the eastern margin of the Tyrrhenian basin. This extensional feature is part of an Oligocene to Present back-arc basin in the hangingwall of the west directed Apennines subduction system. The basin provides excellent conditions to investigate the early stage processes leading to the development of rifted passive margins and to the emplacement of oceanic crust in an oblique setting. The interpreted post-stack-migrated seismic profiles highlight the geometry and kinematics of the Pontine escarpment that connects the Latium-Campania continental margin to the Vavilov basin. The latter is the main feature of the area, related to the early Pliocene extension of the Tyrrhenian Sea. Several morphological variations are pointed out along strike, mirroring different structural settings of the margin itself: a steeper margin to the north corresponds to high-angle possibly transtensional faults, whereas a smooth slope in the southern portion corresponds to several more distributed listric faults. This work contributes to the understanding of the interplay between extensional and transtensional tectonics along the margins of an oblique back-arc basin.

New high-resolution bathymetric and magnetic data from the western Aeolian sector, southern Tyrrhenian Sea, provide insights into structural and volcanic development of the area, suggesting a strong interaction between volcanism and tectonics. The analysis of these data combined with relocated earthquake distribution, focal plane solutions and strain rate evaluation indicates that the dextral strike-slip Sisifo-Alicudi shear zone is a complex and wide area of active deformation, representing the superficial expression of the deep seated lithospheric tear fault separating the subduction slab below Sicily and Calabria. Most of the observed volcanic features are aligned along a NW-SE trend, such as the Filicudi island-Alicudi North Seamount and Eolo-Enarete alignments, and are dissected by hundred-metre-high scarps along conjugate NNE-SSW trending fault systems. The magnetic field pattern matches the main trends of volcanic features. Spectral analysis and Euler deconvolution of magnetic anomalies show the existence of both deep and shallow sources. High-amplitude, high-frequency anomalies due to shallow sources are dominant close to the volcanic edifices of Alicudi and Filicudi, while the main contribution on the surrounding Eolo, Enarete, Alicudi North and Filicudi North seamounts is given by low-amplitude anomalies and/or deeper magnetic sources. This is probably related to different ages of the volcanic rocks, although hydrothermal processes may have played an important role in blanketing magnetic anomalies, in particular at Enarete and Eolo seamounts. Relative chronology of the eruptive centres and the inferred deformation pattern outline the Quaternary evolution of the western Aeolian Arc: Sisifo, Alicudi North and Filicudi North seamounts might have developed in an early stage, following the Late Pliocene-Early Pleistocene SE-ward migration of arc-related volcanism due to the Ionian subduction hinge retreat; Eolo, Enarete and Filicudi represent later manifestations that led volcanoes to develop during Mid-Late Pleistocene, when the stress regime in the area changed, due to the SSE-ward propagation of the subduction slab tear fault and the consequent reorientation and decrease of trench migration velocity. Finally, volcanic activity occurred in a very short time span at Alicudi, where an almost conical volcanic edifice emerged, suggesting negligible interactions with regional fault systems.

Since the exhalative crisis of 2002 cruises were carried out to investigate morphology, magnetic and gravity fields, fluid escape, plume anomalies, biological and microbiological activity, benthic fluxes, early diagenesis, mineralogy and geochemistry of water and sediments of the hydrothermal system of Panarea. The volcanic complex was mapped by multibeam, including backscatter analysis, and magnetometric surveys were done to detect low magnetization in areas with hydrothermal activity, i.e., vents, sulphide deposits, chimney fields. CTD by ship and on ROV detected acidic plumes at bottom (minimum pH value 6.5) and mid depths. An Automatic Benthic Chamber was deployed on a terrace (40m) and in depressions with gascharged and hydrothermally altered sediments (80m). At the 40m site, strong releases of Dissolved Inorganic Carbon (DIC) and Fe, Mn, Zn (75.7, 2.0, 2.9, 3.4 mmol m-2 day-1) were found. Average decrease of pH in the chamber was ~4 units day-1 with a H+ benthic flux of 0.32 mmol m-2 day-1). DIC values of seawater had average 2.3, increasing to 3.1 on degassing vents, while 7.5 mmol was measured on top of a bubbling core. ROV dives explored and sampled several sites; active chimneys (black, red crusts and yellowishorange precipitates at top) were recovered on the SE flanks of Basiluzzo; pH value of 5 was measured aboard on sediments. XRD and XRF data on the external crust showed Fe-Mn oxyhydroxides, including goethite and opal, with Co, Ce, Sr, Zn and Cu enrichments, whereas the inner part are depleted of Fe, Mn and other metals, mostly under detection limits. SEM imagery shows porous filamentous minerals, that are probably bacterial in origin. Dives to SW discovered fields of partially or totally relict chimneys at the same depth (~200m). Chimneys are present on the edges of slope failures and settled on areas of relative lower positive magnetic anomaly, indicating possible shallow depth level of hydrothermal alteration. Reddish crusts and sediments, and acid, gas boiling water (pH 5.5) were cored at 90 m depth upslope of the 'active' chimneys; upslope from the 'relict' chimney's fields, oxized-normal sediments were found. Biological investigations on the sediments revealed a community strongly dominated by the amphipod Ampelisca ledoyeri (43.8 % of the total abundance), probably dwelling in the tubepatches. Rare species were detected on the chimney's samples. The phylogenetic diversity of microbial communities in the precipitates collected on chimneys and on Bottaro vent was analyzed by bacterial and archaeal 16S rDNA clone libraries, showing a dominance of sulfur-oxidazing epsilon and gamma proteobacteria. Very interesting groups of archaea were revealed including methanotrophic Thermoplasmatales and members of SM1 candidate division. Overall prokaryotic diversity was found similar to that of deep sea hydrothermal vents and other sulfidic habitats. White microbial mats were found in an area S of Panarea, on a NS oriented fracture.

We obtained areal variations of crustal thickness, magnetic intensity, and degree of melting of the sub-axial upwelling mantle at Thetis and Nereus Deeps, the two northernmost axial segments of initial oceanic crustal accretion in the Red Sea, where Arabia is separating from Africa. The initial emplacement of oceanic crust occurred at South Thetis and Central Nereus roughly similar to 2.2 and similar to 2 Ma, respectively, and is taking place today in the northern Thetis and southern Nereus tips. Basaltic glasses major and trace element composition suggests a rift-to-drift transition marked by magmatic activity with typical MORB signature, with no contamination by continental lithosphere, but with slight differences in mantle source composition and/or potential temperature between Thetis and Nereus. Eruption rate, spreading rate, magnetic intensity, crustal thickness and degree of mantle melting were highest at both Thetis and Nereus in the very initial phases of oceanic crust accretion, immediately after continental breakup, probably due to fast mantle upwelling enhanced by an initially strong horizontal thermal gradient. This is consistent with a rift model where the lower continental lithosphere has been replaced by upwelling asthenosphere before continental rupturing, implying depth-dependent extension due to decoupling between the upper and lower lithosphere with mantle-lithosphere-necking breakup before crustal-necking breakup. Independent along-axis centers of upwelling form at the rifting stage just before oceanic crust accretion, with buoyancy-driven convection within a hot, low viscosity asthenosphere. Each initial axial cell taps a different asthenospheric source and serves as nucleus for axial propagation of oceanic accretion, resulting in linear segments of spreading.

GP43B-1138

Hydrothermal alteration may weaken volcanic rocks, causing the gravitational instability of portions of active volcanoes with potentially hazardous collapses. Here we show high-resolution multibeam, magnetic and gravity surveys of the Marsili seamount, the largest active volcano of Europe located in the southern Tyrrhenian back-arc basin. These surveys reveal zones with exceptionally low densities and with vanishing magnetizations, due probably to the comminution of basalts during hyaloclastic submarine eruptions and to their post-eruptive hydrothermal alteration. The location of these regions correlates with morphological data showing the occurrence of past collapses. Similar evidence has been obtained from pre-existing data at Vavilov Seamount, another older volcanic system in the Tyrrhenian back-arc basin. Here a large volume of at least 50 km(3) may have collapsed in a single event from its 40 km long western flank. Given the similarities between these volcanoes, a large collapse event may also be expected at Marsili.

Hydrothermal alteration may weaken volcanic rocks, causing the gravitational instability of portions of active volcanoes with potentially hazardous collapses. Here we show high-resolution multibeam, magnetic and gravity surveys of the Marsili seamount, the largest active volcano of Europe located in the southern Tyrrhenian back-arc basin. These surveys reveal zones with exceptionally low densities and with vanishing magnetizations, due probably to the comminution of basalts during hyaloclastic submarine eruptions and to their post-eruptive hydrothermal alteration. The location of these regions correlates with morphological data showing the occurrence of past collapses. Similar evidence has been obtained from pre-existing data at Vavilov Seamount, another older volcanic system in the Tyrrhenian back-arc basin. Here a large volume of at least 50 km(3) may have collapsed in a single event from its 40 km long western flank. Given the similarities between these volcanoes, a large collapse event may also be expected at Marsili. Citation: Caratori Tontini, F., L. Cocchi, F. Muccini, C. Carmisciano, M. Marani, E. Bonatti, M. Ligi, and E. Boschi (2010), Potential-field modeling of collapse-prone submarine volcanoes in the southern Tyrrhenian Sea =(Italy), Geophys. Res. Lett., 37, L03305, doi: 10.1029/2009GL041757.

Mantle-derived serpentinites have been detected at magma-poor rifted margins and above subduction zones, where they are usually produced by fluids released from the slab to the mantle wedge. Here we show evidence of a new class of serpentinite diapirs within the external subduction system of the Calabrian Arc, derived directly from the lower plate. Mantle serpentinites rise through lithospheric faults caused by incipient rifting and the collapse of the accretionary wedge. Mantle-derived diapirism is not linked directly to subduction processes. The serpentinites, formed probably during Mesozoic Tethyan rifting, were carried below the subduction system by plate convergence; lithospheric faults driving margin segmentation act as windows through which inherited serpentinites rise to the sub-seafloor. The discovery of deep-seated seismogenic features coupled with inherited lower plate serpentinite diapirs, provides constraints on mechanisms exposing altered products of mantle peridotite at the seafloor long time after their formation., Understanding subduction zone mechanics and resulting volcanism remains challenging. Here, the authors present seismic reflection profiles from the Mediterranean Sea where serpentinite diapirs are present on the external subduction system of the Calabrian Arc and may be linked to recent volcanism at Etna.

The TOMO-ETNA experiment was planned in order to obtain a detailed geological and structural model of the continental and oceanic crust beneath Mt. Etna volcano and northeastern Sicily up to the Aeolian Islands (southern Italy), by integrating data from active and passive refraction and reflection seismic methodologies, magnetic and gravity surveys. This paper focuses on the marine activities performed within the experiment, which have been carried out in the Ionian and Tyrrhenian Seas, during three multidisciplinary oceanographic cruises, involving three research vessels (“Sarmiento de Gamboa”, “Galatea” and “Aegaeo”) belonging to different countries and institutions. During the offshore surveys about 9700 air-gun shots were produced to achieve a high-resolution seismic tomography through the wide-angle seismic refraction method, covering a total of nearly 2650 km of shooting tracks. To register ground motion, 27 ocean bottom seismometers were deployed, extending the inland seismic permanent network of the Istituto Nazionale di Geofisica e Vulcanologia and a temporary network installed for the experiment. A total of 1410 km of multi-channel seismic reflection profiles were acquired to image the subsurface of the area and to achieve a 2D velocity model for each profile. Multibeam sonar and sub bottom profiler data were also collected. Moreover, a total of 2020 km of magnetic and 680 km of gravity track lines were acquired to compile magnetic and gravity anomaly maps offshore Mt. Etna volcano. Here, high-resolution images of the seafloor, as well as sediment and rock samples, were also collected using a remotely operated vehicle.

Summary Several shallow submarines areas are characterized by considerable releases of hydrocarbon gases, which, during earthquakes or volcanic activity, may suddenly and violently occur. In some instances, changes in chemical and physical properties of gas emissions, which are generated by geothermal systems connected to the volcanoes’ plumbing system, are important precursors of volcanic activity and useful indices for the study of the geothermal field. Furthermore, some superficial structures such faults, landslide slopes or archaeological relics should be studied with such a high detail that geophysical and bathymetric surveys are unable to provide. In response to the needs increasingly felt of a completely customizable low cost tool for geological/geophysical/geochemical investigation of shallow submarine system, in the framework of the ROVER project, starting from an international project called OpenROV, is being implemented a micro-ROV for multidisciplinary environmental investigation. In this paper, we will describe the project progress, with particular reference to the first tests conducted in pool and in sea water, the geophysical/geochemical instrumentation of which will be equipped and the automatic control algorithms that are being developed for the semi-automatic navigation.