Active deformation evidence in the offshore of western Calabria (southern Tyrrhenian Sea) from ultra-resolution multichannel seismic reflection data: results from the Gulf of Sant'Eufemia

An ultra-resolution, multichannel seismic reflection data set was collected during an oceanographic cruise organised in the frame of the “Earthquake Potential of Active Faults using offshore Geological and Morphological Indicators” (EPAF) project, which was founded by the Scientific and Technological Cooperation (Scientific Track 2017) between the Italian Ministry of Foreign Affairs and International Cooperation and the Ministry of Science, Technology and Space of the State of Israel. The data acquisition approach was based on innovative technologies for the offshore imaging of stratigraphy and structures along continental margins with a horizontal and vertical resolution at decimetric scale. In this work, we present the methodology used for the 2D HR-seismic reflection data acquisition and the preliminary interpretation of the data set. The 2D seismic data were acquired onboard the R/V Atlante by using an innovative data acquisition equipment composed by a dual-sources Sparker system and one HR 48-channel, slant streamers, with group spacing variable from 1 to 2 meters, at 10 kHz sampling rate. An innovative navigation system was used to perform all necessary computations to determining real-time positions of sources and receivers. The resolution of the seismic profiles obtained from this experiment is remarkable high respect to previously acquired seismic data for both scientific and industrial purposes. In addition to the seismic imaging, gravity core data were also collected for sedimentological analysis and to give a chronological constraint using radiocarbon datings to the shallower reflectors. The investigated area is located in the western offshore sector of the Calabrian Arc (southern Tyrrhenian Sea) where previous research works, based on multichannel seismic profiles coupled with Chirp profiles, have documented the presence of an active fault system. One of the identified faults was tentatively considered as the source of the Mw 7, 8 September 1905 seismic event that hit with highest macroseismic intensities the western part of central Calabria, and was followed by a tsunami that inundated the coastline between Capo Vaticano and the Angitola plain. On this basis, the earthquake was considered to have a source at sea, but so far, the location, geometry and kinematics of the causative fault are still poorly understood. In this study we provide preliminary results of the most technologically advanced ultra-high-resolution geophysical method used to reveal the 3D faulting pattern, the late Quaternary slip rate and the earthquake potential of the marine fault system located close to the densely populated west coast of Calabria

DAVID The First 6U Cubesat Mission of the Italian Space Agency Programme Iperdrone as Demonstration of New On Orbit Services Performed by Space Drones

The Italian Space Agency is promoting a roadmap for the design, manufacturing and operation of a new space reentry drone. The Iperdrone program will qualify a new type of operative mission, through an incremental phased approach. The program includes, as first step, the demonstration of inspection services for the International Space Station, optimizing the EVA activities and increasing the in space experimentation opportunities. The paper will present the status of development of the first mission, which will demonstrate the system\u27s capabilities such as proximity operations, inspection and interaction with a target, including a close rendez-vous demonstration. The first mission, DAVID to be launched within 2023, is based on a 6U cubesat architecture

The use and beauty of ultra-high-resolution seismic reflection imaging in Late Quaternary marine volcaniclastic settings, Bay of Naples, Italy

A Nápolyi-öbölben felvett ultra nagy felbontású egycsatornás (IKB-Seistec™) reflexiós szeizmikus szelvények korábbi geológiai és geofizikai vizsgálatok eredményeivel együtt kivételes, eddig soha nem látott felbontású szeizmikus leképezését nyújtják a Flegrei-mezők és a Somma-Vezúv felszín alá süllyedt késő-pleisztocén–holocén rétegtani felépí - tésének. A szeizmikus szelvényeken látott geometria és gravitációs magvevővel nyert üledékek adatainak összevetéséből Campania partközeli kontinentális talapzatán számos olyan üledékes és vulkáni szerkezet, valamint hidrotermális jelenség került leképezésre, melyek a legutolsó glaciális maximum (kb. 18 000 év) óta keletkeztek. A Pozzuoli-öbölben mért Seistec szelvények jól mutatják a beomlott kaldera gyűrűs vetőjét, a kb. 15 ezer éves Nápolyi Sárga Tufa (NYT) lerakódáshoz vezető kitöréskor felújuló boltozatot, és alátámasztják a deformáció későnegyedidőszaki korára és stílusára vonatkozó hipotéziseket. A szeizmikus szelvényeken látható a NYT rétegeinek töréses szerkezete, valamint hidrotermális fluidum-feláramlások és vulkáni/szubvulkáni intrúziók a gyűrűs vetők mentén. A Somma-Vezúv rétegvulkán előterében a kontinentális talapzat felett mért szeizmikus szelvények leképezték a Vezúv i.sz. 79-es kitörésekor Herculaneum városát elpusztító piroklaszt-ár tengervízbe érésekor keletkező, gravitációsan összeomló homokhullámok szerkezetét is. A Somma-Vezúv és a Pozzuoli-öböl közti, buckás felszínű Banco della Montagna területén mért szelvények és fúrómagok vulkanoklasztos diapírok sorát tárták fel. Ezeket a konszolidálatlan horzsakőből álló testeket a fluidum - feláramlás és aktív kigázosodás hatására kialakult mélybeli túlnyomás hozta fel a tengerfenékre.Very high-resolution, single channel (IKB-Seistec™) reflection seizmic profiles acquired in the Bay of Naples, com - plemented with geological and geophysical data from the literature, provide unprecedented, superb seismic imaging of the latest Pleistocene–Holocene stratigraphic architecture of the submerged sectors Campi Flegrei and Somma-Vesuvius volcanic districts. Seismic profiles were calibrated by gravity core data and document a range of depositional systems, volcanic structures and hydrothermal features that evolved after the onset of the Last Glacial Maximum (~ 18 ka BP) over the continental shelf on the Campania coastal zone. Seistec profiles from the Pozzuoli Bay yield high-resolution images of the shallow structure of the collapse caldera-ring fault — resurgent dome system associated with the eruption of the Neapolitan Yellow Tuff (NYT) (ca 15 ka) and support a working hypothesis to assess the timing and the styles of deformation of the NYT resurgent structure throughout the latest Quaternary. Seismic images also revealed the nature of the fragile deformation of strata along the NYT ring fault system and the occurrence of hydrothermal fluids and volcanic/subvolcanic intrusions ascending along the ring fault zone. Seismic data acquired over the continental shelf off the Somma-Vesuvius stratovolcano, display evidence of gravit - ational instability of wavy bedforms representing the submarine prosecution of pyroclastic flows originated from the Vesuvius during the eruption that destroyed the Roman city of Herculaneum in 79 CE. At the Banco della Montagna, a hummocky seafloor knoll located between the Somma-Vesuvius and the Pozzuoli Bay, seismic profiles and gravity core data revealed the occurrence of a field of volcaniclastic diapirs formed by the dragging and rising up of unconsolidated pumice, as a consequence of fluid overpressure at depth associated with active degassing and fluid venting at the seafloor

A roadmap for amphibious drilling at the Campi Flegrei caldera: insights from a MagellanPlus workshop

Large calderas are among the Earth's major volcanic features. They are associated with large magma reservoirs and elevated geothermal gradients. Caldera-forming eruptions result from the withdrawal and collapse of the magma chambers and produce large-volume pyroclastic deposits and later-stage deformation related to post-caldera resurgence and volcanism. Unrest episodes are not always followed by an eruption; however, every eruption is preceded by unrest. The Campi Flegrei caldera (CFc), located along the eastern Tyrrhenian coastline in southern Italy, is close to the densely populated area of Naples. It is one of the most dangerous volcanoes on Earth and represents a key example of an active, resurgent caldera. It has been traditionally interpreted as a nested caldera formed by collapses during the 100–200 km3 Campanian Ignimbrite (CI) eruption at ∼39 ka and the 40 km3 eruption of the Neapolitan Yellow Tuff (NYT) at ∼15 ka. Recent studies have suggested that the CI may instead have been fed by a fissure eruption from the Campanian Plain, north of Campi Flegrei. A MagellanPlus workshop was held in Naples, Italy, on 25–28 February 2017 to explore the potential of the CFc as target for an amphibious drilling project within the International Ocean Discovery Program (IODP) and the International Continental Drilling Program (ICDP). It was agreed that Campi Flegrei is an ideal site to investigate the mechanisms of caldera formation and associated post-caldera dynamics and to analyze the still poorly understood interplay between hydrothermal and magmatic processes. A coordinated onshore–offshore drilling strategy has been developed to reconstruct the structure and evolution of Campi Flegrei and to investigate volcanic precursors by examining (a) the succession of volcanic and hydrothermal products and related processes, (b) the inner structure of the caldera resurgence, (c) the physical, chemical, and biological characteristics of the hydrothermal system and offshore sediments, and (d) the geological expression of the phreatic and hydromagmatic eruptions, hydrothermal degassing, sedimentary structures, and other records of these phenomena. The deployment of a multiparametric in situ monitoring system at depth will enable near-real-time tracking of changes in the magma reservoir and hydrothermal system

Architecture and kinematics of forearc basins and intra-caldera resurgences: new insight from the Paola Basin (western offshore Calabria region) and the Campi Flegrei caldera (Campania region)

This thesis deals with the patterns of tectonic deformation at different time and spatial scales ranging from tens to millions of years and from one to tens of kilometers, respectively. The study areas are the Campi Flegrei (Campania region, Italy) and Paola Basin (western offshore Calabria region, Italy). The Campi Flegrei and its offshore prolongation, the Pozzuoli Bay, are a laboratory for investigating volcano-tectonic deformations at 1yr-1kyr timescale and 1km spatial scale related to the dynamics of the Neapolitan Yellow Tuff (NYT) caldera and its intra-caldera resurgence. Resurgence is the late stage, long-term uplift of a collapse caldera floor to form a dome-like structure. The comprehension of its development and structural pattern is crucial for predicting the caldera behaviour during periods of unrest. This work investigates the resurgent activity of the NYT caldera using an integrated analysis of high-resolution swath bathymetry, reflection seismic profiles and interferometric synthetic-aperture radar (InSAR) data. The interpretation of the data shows that resurgence affects a ~ 50 km2 wide almost circular area centred in the Pozzuoli harbor. The resurgent area is surrounded by a ~ 3-4 km wide structural discontinuity corresponding to the Ring Fault Zone (RFZ) that formed during the NYT caldera collapse (~15 ka BP). The uplift of the caldera resurgence occurs along a series of inward-dipping reverse faults of the RFZ characterized by a decreasing-upward inclination of fault planes from ~70° to ~15°. The development of these structures is controlled by the reactivation and deformation of pre-exiting normal faults associated with the NYT caldera collapse. Deformation of reactivated faults often results in folding of overlying and/or juxtaposed strata, in the style of ~ 500 m wide antiformal folds, mostly located along the periphery of the resurgent area. The structural pattern of the resurgence consists of disjoint uplifted blocks of the caldera floor. Two main structural elements are detected inside the resurgent area both off- and onshore, separated by a NNE-SSW trending high-angle normal fault. The most uplifted block comprises the area from Mt Nuovo to La Pietra, whereas the adjacent uplifted sector extends eastwards to include Mt Spina. The morpho-bathymetric expression of the two uplifted blocks is represented by a ~5 km wide antiformal structure, encircled by Bagnoli and Epitaffio valleys. In the hinge zone of the resurgent dome a series of high-angle normal faults form a small apical graben. In order to analyze long term deformations (Myr timescale) occurring at a tens of kilometers spatial scale, this study focuses on the Paola Basin, a segment of the forearc region of the Tyrrhenian-Ionian subduction system. Fore-arc basins are parts of fore-arc region that form structurally in response to a variety of subduction zone processes. The sedimentary infill records the complex tectono-stratigraphic evolution of basin associated with subduction system, and thus, allows deciphering the formation mechanisms of basins developed in compressional intraplate settings. We analyse these processes in the Paola Basin using reflection seismic profiles and bathymetric data. The Paola Basin is a NNW-SSE trending asymmetric syncline, bounded by the offshore sector of the Coastal Chain to the East and by the regional-scale Paola Anticline to the West. It hosts up to 5.5 km thick Plio-Quaternary deposits, most of them showing eastward-dipping clinoforms. These latter are associated to shelfal progradation, supplied from the north via longshore currents, dispersing sediments from unknown Apenninic/Sila entry points. A local circulation of longshore currents flowed southwards and dispersed sediments from unknown Apenninic/Sila entry points. An aggradational internal geometry characterizes the uppermost part of the sedimentary infill with a thickness decreasing westwards, suggesting a sediment supply from the Coastal Chain. In the Early Pliocene, the proto Paola Basin extended from the Paola Anticline up to the western flank of the Sila Massif. Since ∼ 3.5 Ma, the uplift of the Coastal Chain shortened the proto Paola Basin, leading to the separation of the basin from the Crati basin. Short wavelength (∼ 80 km) lithospheric buckling, caused by a ENE-WSW oriented, arc-normal paleo-stress field, is the most likely mechanism that explains the pattern of tectonic subsidence of the Paola Basin, the uplift of the Paola Anticline and part of the uplift experienced by Sila Massif during the Plio-Quaternary. Kilometre-scale, strike-slip restraining and releasing bends are widely spread over the hinge zone of the Paola Anticline, defining the Paola Ridge. Their formation is compatible with an NW-SE oriented maximum stress axis meanwhile strike-slip fault accommodates the arc-parallel component of the plate motion. The change in direction from ENE-WSW to NW-SE of the maximum stress axis in the fore-arc region is a consequence of the transition from orthogonal to oblique subduction, associated to the bending of the Northern Calabria Arc. Regional uplift and folding of the Northern Calabrian Arc induced tensile stress resulting in the formation of N-S trending normal faults in the extrados of the Sila Massif anticline. In this context, the Paola Basin can be defined as a “Neutral Accretionary-type” forearc basin

Arc and forearc rifting in the Tyrrhenian subduction system

The evolution of forearc and backarc domains is usually treated separately, as they are separated by a volcanic arc. We analyse their spatial and temporal relationships in the Tyrrhenian subduction system, using seismic profiles and numerical modelling. A volcanic arc, which included the Marsili volcano, was involved in arc-rifting during the Pliocene. This process led to the formation of an oceanic backarc basin (~ 1.8 Ma) to the west of the Marsili volcano. The eastern region corresponded to the forearc domain, floored by serpentinised mantle. Here, a new volcanic arc formed at ~ 1 Ma, marking the onset of the forearc-rifting. This work highlights that fluids and melts induce weakening of the volcanic arc region and drive the arc-rifting that led to the backarc basin formation. Later, the slab rollback causes the trench-ward migration of volcanism that led to the forearc- rifting under the control of fluids released from the downgoing plate.ISSN:2045-232

Active Tectonics along the South East Offshore Margin of Mt. Etna: New Insights from High-Resolution Seismic Profiles

The offshore margin of Mt. Etna has been shaped by Middle Pleistocene to Holocene shortening and extension and, more recently, by gravity-related sliding of the volcanic edifice. These processes have acted contemporaneously although the gravitational component largely prevails over the tectonic one. In order to investigate this issue, we focused on the main role of active tectonics along the south-eastern offshore of Mt. Etna by means of marine high-resolution seismic data. Seismic profiles revealed post-220 ka sedimentary deposits unconformably overlaying the Lower-Middle Pleistocene Etnean clayey substratum and volcanics of the Basal Tholeiitic phase and the Timpe phase. Offshore Aci Trezza-Catania, the architecture of the sedimentary deposits reflects syn-tectonic deposition occurred into “piggy-back” basin setting. Shortening rate was estimated at ~0.5 mm/a since ~220 ka. Asymmetric folding also involves post Last Glacial Maximum deposits, evidencing that compressional deformation is still active. In the continental slope, a belt of normal faults offset the Lower-Middle Pleistocene Etnean clayey substratum and younger deposits, also producing seafloor ruptures. Thrust and fold structures can be related to the recent migration of the Sicilian chain front, while extensional faults are interpreted as part of a major tectonic boundary located in the Ionian offshore of Sicily

The use and beauty of ultra-high-resolution seismic reflection imaging in late quaternary marine volcaniclastic settings, bay of Naples, Italy

Very high-resolution, single channel (IKB-Seistec™) reflection profiles acquired offshore the Napoli Bay, complemented with geological and geophysical data from the literature, provide unprecedented, superb seismic imaging of the Latest Pleistocene-Holocene stratigraphic architecture of the submerged sectors Campi Flegrei and Somma-Vesuvius volcanic districts. Seismic profiles were calibrated by gravity core data and document a range of depositional systems, volcanic structures and hydrothermal features that evolved after the onset of the Last Glacial Maximum (ca. 18 ka BP) over the continental shelf on the Campania coastal zone. Seistec profiles from the Pozzuoli Bay yield high-resolution images of the shallow structure of the collapse caldera-ring fault - resurgent dome system associated with the eruption of the Neapolitan Yellow Tuff (NYT) (ca 15 ka BP) and support a working hypothesis to assess the timing and the styles of deformation of the NYT resurgent structure throughout the Latest Quaternary. Seismic images also revealed the nature of the fragile deformation of strata along the NYT ring fault system and the occurrence of hydrothermal fluids and volcanic/sub-volcanic intrusions ascending along the ring fault zone. Seismic data acquired over the continental shelf off the Somma-Vesuvius stratovolcano, display evidence of gravitational instability of sand wave deposits originated by the underwater modification of pyroclastic flows that entered the seawater after destroying the Roman city of Herculaneum during the 79 CE eruption of Vesuvius. At the Banco della Montagna, a hummocky seafloor knoll located between the Somma-Vesuvius and the Pozzuoli Bay, seismic profiles and gravity core data revealed the occurrence of a field of volcaniclastic diapirs formed by the dragging and rising up of unconsolidated pumice, as a consequence of fluid overpressure at depth associated with active degassing and fluid venting at the seafloor

Architecture and 15 ka to present volcano-tectono-sedimentary evolution of the Neapolitan Yellow Tuff caldera offshore the Campi Flegrei, (Naples, Eastern Tyrrhenian Margin)

The Campi Flegrei area is structurally dominated by the caldera associated with the eruption of the Neapolitan Yellow Tuff (NYT), a 40 km3 DRE ignimbrite dated at ca 15 ka BP [Deino et al., 2004], The volcanological evolution of the NYT caldera as been long described on the basis of outcrop and subsurface studies onland [Rosi & Sbrana, 1987; Orsi et al., 1996, and references therein; Di Vito et al., 1999; Perrotta et al., 2006; Fedele et al., 2011], but its offshore morphology, the stratal geometry of the volcaniclastic products and structures and the late-stage geodynamic evolution of the inner caldera resurgence are still poorly known. We integrate geological and geophysical data obtained from high-resolution reflection seismic profiles (Sparker and Chirp sources) with gravity cores and swath bathymetry to better constrain the shallow structure and stratigraphic architecture and latest Quaternary to Holocene evolution of the submerged sector of the NYT caldera off the Pozzuoli Bay. Our data clearly image, for the first time, the offshore geometry of the NYT caldera ring-fault zone, as well as the volcano-tectono-sedimentary evolution associated with the late stage evolution of the NYT inner caldera resurgence. Our interpretation suggests that since 15 ka the offshore sector of NYT inner caldera underwent significant deformation and uplift (with minor subsidence episodes) that occurred almost at the same rate as the post-glacial sea-level rise. Particularly, the inner Pozzuoli Bay started to deform soon after 15 ka BP, when the sea-level rise was initially faster than uplift. This caused a general increase of the accommodation space that was progressively filled up by volcaniclastic sediments. Since ca. 8 ka BP, along with the mid Holocene decrease in the rate of the sea-level rise, the early NYT resurgent structure was then uplifted up to the sea-level or even to partial subaerial exposure. From ca. 8 to 5 ka BP two distinct layers of resediments, mostly represented by density current deposits, separated by an interval of hemipelagic sediments. The two density flow units display a remarkable difference in their thickness and internal geometry. Across the bay, the lower unit is ca 5m thick in the western sector and reaches its maximum of ca 10 m in the central sector while it is absent towards the east. The upper unit, on the contrary, displays the minimum thickness of 10 m close to the central sector of the bay and increases up to ca 16 and 12 m in the western and eastern sector of the bay, respectively. The variation in thickness of the density flow deposits appears to be related with the amount of sediments available. The upper density flow deposits is also internally more chaotic respect to the lower one, suggesting higher energy and/or turbulence A significant post 2 ka BP subsidence phase of ca 10 m is then recorded offshore Pozzuoli by the drowning of the infralittoral prograding wedge below the present-day fair-weather wave base. Sections clearly illustrate that the basin depocentre topography is not fixed at one position but migrates southwards in time. We suggest that the uplift of the resurgent dome and subsidence of the southern sector, occurred after the eruption of the NYT, acted as a major control in the increase of the sea-floor gradient in the Pozzuoli bay. This may have triggered in turn, the deposition of gravity flow deposits along with a progressive migration of basin depocentres through time