We present the results of a detailed bathymetric survey of Pozzuoli Bay (Gulf of Naples, Italy). This shallow marine area, along with the Campi Flegrei inland, is a highly active volcanic district in the coastal zone of SW Italy. The area has been active since at least 78 ka B.P., and is structurally dominated by a caldera collapse ( 8 km in diameter) associated with the eruption of the Neapolitan Yellow Tuff (NYT), a 30 -50 km 3 dense rock equivalent (DRE) ignimbrite dated 15 ka B.P. The main cartographic product consists of a 1:10,000 scale morpho-bathymetric map of Pozzuoli Bay, derived from 1 m cell-size, colour hill-shaded, digital terrain model of the seafloor. Multibeam bathymetry data reveal the precise extent of Roman underwater archaeological remains located in the N -NW infralittoral zone of the Bay. Morphometric analysis allowed for the development of thematic representations, including slope and aspect maps. A complete data set of active fluid vents seafloor locations were also recorded during the survey and reported in the final map. The multibeam bathymetric survey illustrated in this study provides an unprecedentedly detailed image of the seafloor morphology of Pozzuoli Bay and represents a contribution to the understanding of the dynamic evolution of the Campi Flegrei caldera, a high-risk volcanic area densely populated by almost one million people.

We report evidences of active seabed doming and gas discharge few kilometers offshore from the Naples harbor (Italy). Pockmarks, mounds, and craters characterize the seabed. These morphologies represent the top of shallow crustal structures including pagodas, faults and folds affecting the present-day seabed. They record upraise, pressurization, and release of He and CO2 from mantle melts and decarbonation reactions of crustal rocks. These gases are likely similar to those that feed the hydrothermal systems of the Ischia, Campi Flegrei and Somma-Vesuvius active volcanoes, suggesting the occurrence of a mantle source variously mixed to crustal fluids beneath the Gulf of Naples. The seafloor swelling and breaching by gas upraising and pressurization processes require overpressures in the order of 2–3 MPa. Seabed doming, faulting, and gas discharge are manifestations of non-volcanic unrests potentially preluding submarine eruptions and/or hydrothermal explosions.

High-resolution, single-channel seismic and multibeam bathymetry data collected at the Amendolara Ridge, a key submarine area marking the junction between the Apennine collision belt and the Calabrian subduction forearc, reveal active deformation in a supposedly stable crustal sector. New data, integrated with existing multichannel seismic profiles calibrated with oil-exploratory wells, show that middle to late Pleistocene sediments are deformed in growth folds above blind oblique-reverse faults that bound a regional pop-up. Data analysis indicates that~10 to 20 km long banks that top the~80 km long, NW-SE trending ridge are structural culminations above en echelon fault segments. Numeric modeling of bathymetry and stratigraphic markers suggests that three 45°dipping upper crustal (2-10 km) fault segments underlie the ridge, with slip rates up to~0.5 mm/yr. Segments may be capable with M~6.1-6.3 earthquakes, although an unknown fraction of aseismic slip undoubtedly contributes to deformation. The fault array that bounds the southern flank of the ridge (Amendolara Fault System) parallels a belt of M w < 4.7 strike-slip and thrust earthquakes, which suggest current left-oblique reverse motion on the array. The eastern segment of the array shows apparent morphologic evidence of deformation and might be responsible for M w ≤ 5.2 historic events. Late Pliocene-Quaternary growth of the oblique contractional belt is related to the combined effects of stalling of Adriatic slab retreat underneath the Apennines and subduction retreat of the Ionian slab underneath Calabria. Deformation localization was controlled by an inherited mechanical interface between the thick Apulian (Adriatic) platform crust and the attenuated Ionian Basin crust.

Subduction-transform edge propagators are lithospheric tears bounding slabs and back-arc basins. The volcanism at these edges is enigmatic because it is lacking comprehensive geological and geophysical data. Here we present bathymetric, potential-field data, and direct observations of the seafloor on the 90 km long Palinuro volcanic chain overlapping the E-W striking tear of the roll-backing Ionian slab in Southern Tyrrhenian Sea. The volcanic chain includes arc-type central volcanoes and fissural, spreading-type centers emplaced along second-order shears. The volume of the volcanic chain is larger than that of the neighbor island-arc edifices and back-arc spreading center. Such large volume of magma is associated to an upwelling of the isotherms due to mantle melts upraising from the rear of the slab along the tear fault. The subduction-transform edge volcanism focuses localized spreading processes and its magnitude is underestimated. This volcanism characterizes the subduction settings associated to volcanic arcs and back-arc spreading centers.

No abstract

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. a b s t r a c tThe magnitude and rate of Late PleistoceneeHolocene vertical tectonic movements offshore of the Capo Vaticano Promontory (western Calabria, southern Italy) have been measured on the basis of the presentday depth variations of the edges of submerged depositional terraces (and associated abrasion platforms) that formed below the storm-wave base, during the sea level stillstand of the Last Glacial Maximum (LGM). These depositional features, represented by submerged prograding wedges and an associated terrace-shaped upper boundary, have been identified in high-resolution seismic reflection profiles acquired along the continental shelf and the upper slope of the promontory, and are referred to in this study as "Lowstand Infralittoral Prograding Wedges (LIPWs)". Our new data and methods provide evidence that LIPWs can be used as geomorphological indicators of vertical movements in offshore settings with well controlled uncertainty. Removal of the non-tectonic component of vertical changes using an ice-volume equivalent eustatic sea level compilation indicates w11 (AE3.2) m of uplift and w25 (AE3.2) m of subsidence, from southwest to northeast, along the promontory, over a distance of w22 km, during the post-LGM. The resulting uplift and subsidence rates (including both regional and local components) for the last 20.350 (AE1.35) years are 0.54 (AE0.2) mm/y and 1.23 (AE0.25) mm/y, respectively. These results are consistent with longer-term estimates based on uplifted 215e82 ka old coastal terraces and Late Holocene shorelines. This integration of offshore and coastal markers indicates a pattern of vertical movements characterized by a marked asymmetry associated with a northeast down tilt of the Capo Vaticano Promontory. The calculated tilt rate increases by one order of magnitude during the post-LGM in respect to the time interval from 215 to 82 BP. Displacement associated with the NWeSE striking normal fault that bound the Capo Vaticano Promontory to the Gioia Tauro Basin ended in the (?) Pleistocene, and thus does not contribute to the tilt of the promontory at least during the last 215 ka.

The Gulf of Patti and its onshore sector represent one of the most seismically\ud active regions of the Italian Peninsula. Over the period 1984–2014, about 1800 earthquakes\ud with small-to-moderate magnitude and a maximum hypocentral depth of 40 km occurred\ud in this area. Historical catalogues reveal that the same area was affected by several strong\ud earthquakes such as the Mw = 6.1 event in April 1978 and the Mw = 6.2 one in March\ud 1786 which have caused severe damages in the surrounding localities. The main seismotectonic\ud feature affecting this area is represented by a NNW–SSE trending right-lateral\ud strike-slip fault system called ‘‘Aeolian–Tindari–Letojanni’’ (ATLFS) which has been\ud interpreted as a lithospheric transfer zone extending from the Aeolian Islands to the Ionian\ud coast of Sicily. Although the large-scale role of the ATLFS is widely accepted, several\ud issues about its structural architecture (i.e. distribution, attitude and slip of fault segments)\ud and the active deformation pattern are poorly constrained, particularly in the offshore. An\ud integrated analysis of field structural geology with marine geophysical and seismological\ud data has allowed to better understand the structural fabric of the ATLFS which, in the study\ud area, is expressed by two major NW–SE trending, en-echelon arranged fault segments.\ud Minor NNE–SSW oriented extensional structures mainly occur in the overlap region\ud between major faults, forming a dilatational stepover. Most faults display evidence of\ud active deformation and appear to control the main morphobathymetric features. This aspect, together with diffused continental slope instability, must be considered for the\ud revaluation of the seismic and geomorphological hazard of this sector of southern\ud Tyrrhenian Sea

No abstract