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Continental Rift systems often involve narrow regions, which accommodate all the stretching. In some cases, the initial extension occurs with a diffuse style and may successively produce a narrow rift. An example is the West Antarctica Rift System, bearing evidence of the concurrent formation of multiple basins normal to the rift axis. This rift system has undergone extension between the Cretaceous and the middle Neogene age (105 to 11 Ma [1, 2]), due to the sea floor spreading in the northwestern Ross Sea. It is composed of three main basins (Victoria Land Basin, Central Trough, and Eastern Basin), which cover a present-day length of 900-1000 km, encompassing the lateral contact between the cratonic domains of East Antarctica and West Antarctica Phanerozoic lithosphere. The different basins, bounded by structural highs, exhibit significant variations in the thickness and thinning of the underlying crust and lithosphere. This multiple-basin pattern suggests that, at least for some part of the rifting, the deformation occurred in a diffuse way, instead of being localized in a small portion of the rift system [3].The factors controlling these deformation styles have been identified in the inheritance of structures and thermal/rheological heterogeneities [4], which acted concurrently with the extensional kinematics in shaping the present-day rift architectures. Therefore, an improved knowledge on how different thermo-structural initial conditions (e.g. lateral contacts, thermal transients, accumulated strain softening) influence the outcome of rifting may help identify the most likely state at the onset of rifting. To this purpose, we implement a series of numerical models, testing several starting structural conditions (rheology, temperature, prior damage) and distribution of extensional velocity (a single phase or multiple pulses, for the same total extension) that could trigger this peculiar diffuse deformation pattern.To build a 2-D simplified geometry of the structures of the rift system, we took as a reference the seismic profiles BGR-02 and ACRUP2, normal to the rift axis, along the 77° S parallel [5]. We assumed an initial crustal thickness of about 50 km and a kinematic pattern consisting of two main distinct extension phases, covering the Cretaceous-Cenozoic interval [1, 6].Modelling was carried out using the open source Underworld2 code [7], which relies on Lagrangian integration point finite element approach and provides a Python API to construct, run, and visualize the output of geodynamic models. The results show that the models that are more consistent with the observations require the existence of peculiar a-priori inherited features. In addition to the role of inheritance, diffuse patterns are favoured, for the same extension amount, by slow and long-lasting rifting phases, with respect to fast and short time pulses.This work was carried out in the context of PNRA project "Onset of Antarctic Ice Sheet Vulnerability to Oceanic conditions (ANTIPODE)".[1] Behrendt et al. (1991) https://doi.org/10.1029/91TC00868[2] Granot & Dyment (2018) https://doi.org/10.1038/s41467-018-05270-w[3] Huerta & Harry (2007) https://doi.org/10.1016/j.epsl.2006.12.011[4] Perron et al. (2021) https://doi.org/10.1051/bsgf/2020038[5] Trey et al. (1999) https://doi.org/10.1016/S0040-1951(98)00155-3[6] Davey & De Santis (2006) https://doi.org/10.1007/3-540-32934-X_38[7] Mansour et al. (2020) https://doi.org/10.21105/joss.01797

Increasing demand for freshwater requires the identification of additional and less-conventional water resources. Amongst these, offshore freshened groundwater is considered a new opportunity to face increasing water demand and has been studied in different parts of the world. Here we focus on the north-eastern Adriatic Sea, where offshore aquifers could be present as a continuation of onshore aquifers. Geophysical data, especially offshore seismic data, as well as onshore and offshore well data were integrated and interpreted to characterize the hydrogeological setting via the interpretation of seismo-stratigraphic sequences. Two areas located in the proximity of the Tagliamento and Isonzo deltas were studied. Well and seismic data suggest that Quaternary sediments, extending from onshore to offshore areas, represent the most promising from an offshore freshwater resources point of view. Firstly, onshore well data confirm the presence of freshwater aquifer systems in proximity to the coastline, supporting the hypothesis of their continuation offshore. Secondly, during the glacial periods, a drop in sea level (about -120 m with respect to today during the Last Glacial Maximum ), provided the total emergence of the northern Adriatic Sea, that represented a fluvial plain, allowing the storage of freshwater. Moreover, a lower sea level position could lead to a higher groundwater gradients towards offshore areas. On the contrary, during the interglacial ones, the sea level was some meters higher than the present one (about +8 m during the last transgression in the Middle/Late Pleistocene), with mainly starved conditions. During the deglaciation phases, the fluvial drainage fed by melting glaciers produced the deposition of sediment above the plain. Below these sediments, the several kilometres thick pre-Quaternary carbonate and terrigenous sequences seem to host mainly salty waters.

The present-day morpho-stratigraphy of the Ross Sea is the result of Cenozoic tectonic and cryospheric events, and constitutes a key record of Antarctica's cryospheric evolution. An enduring problem in interpreting this record in a broader regional context is that the correlation between eastern and western Ross Sea stratigraphy has remained uncertain due to the limited number of drill sites. We correlate the glacial-related features observed on a dense network of seismic reflection profiles in McMurdo Sound with those identified in the Nordenskjöld and Drygalski Basins, as well as the basins farther east in the central Ross Sea. We present an improved correlation of the regional patterns of early to middle Miocene ice-sheet variance across the Ross Sea constrained by new evaluation of seismic facies and age models from one site recovered by the Antarctic Drilling Project (ANDRILL) in the southwestern most part of McMurdo Sound. We also integrate this correlation with the recently published seismic framework in the central Ross Sea. The formation of U-shaped valleys during the early Miocene in McMurdo Sound, together with prograding sedimentary wedges in the western-most basins, and the central Ross Sea, suggest two major phases of overall advance of a marine-terminating ice sheet between ~18 Ma and ~ 17.4 Ma. Widespread formation of turbiditic channel-levee systems in McMurdo Sound and rapid sediment deposition in Nordernskjöld Basin point to subsequent ice-sheet retreat between ~17.4 Ma and ~ 15.8 Ma, coinciding with the onset of the Miocene Climate Optimum (MCO; ~17–14.5 Ma). However, the carving of troughs and formation of irregular morphologic features suggest that an extensive ice sheet still remained along the western Ross margin at ~17.4 Ma and a brief episode of ice-sheet advance occurred at ~16.8 Ma in the earliest interval of the MCO. Subsequent marine-based ice sheet advance during the Middle Miocene Climate Transition (MMCT, ~14.0–13.8 Ma) is indicated by widespread erosional features. Our results reconcile the semi-continouous seismic and drill core stratigraphy of the offshore Ross Sea continental shelf with inferences of ice sheet dynamics from continuous far-field deep sea and sea level records, as well as the highly discontinous (and heavily debated) onshore records of pre-MMCT glaciation and aridification of the Transantarctic Mountains at 14 Ma.

We present the results of a geophysical study carried out in the Isonzo Plain (NE of Italy), where the Paleogene External Dinarides and the Neogene eastern Southern Alps merge. We aim to provide imaging on the geological and tectonic setting in the area of convergence of the two chains. To this purpose multichannel seismic and geo-electrical profiles were acquired. Seismic processing and tomographic inversion of the first arrivals of multichannel seismic data were performed, allowing us to define geometries and velocities of the buried structures.Our data indicate the occurrence of a deformed Dinaric foredeep due to the Paleogene south-west migration of the External Dinaric chain and to the Neogene tectonic activity of the S-verging eastern South-Alpine chain. In addition, Plio-Quaternary transpressional fault systems produced structural highs such as the rocky outcrop of the Farra Hills rising from the plain. Plio-Quaternary tectonic activity displaced the late Miocene - Pliocene erosive surface at the top of the terrigenous sediment that fills the foredeep. The imaging of the buried structures provide a possible correlation with those outcropping in the Collio Hills and Karst Plateau.

Paleo-bathymetric reconstructions provide boundary conditions to numerical models of ice sheet evolution and ocean circulation that are critical to understanding their evolution through time. The geological community lacks a complex open-source tool that allows for community implementations and strengthens research synergies. To fill this gap, we present PALEOSTRIPv1.0, a MATLAB open-source software designed to perform 1D, 2D, and 3D backtracking of paleo-bathymetries. PALEOSTRIP comes with a graphical user interface (GUI) to facilitate computation of sensitivity tests and to allow the users to switch all the different processes on and off and thus separate the various aspects of backtracking. As such, all physical parameters can be modified from the GUI. It includes 3D flexural isostasy, 1D thermal subsidence, and possibilities to correct for prescribed sea level and dynamical topography changes. In the following, we detail the physics embedded within PALEOSTRIP, and we show its application using a drilling site (1D), a transect (2D), and a map (3D), taking the Ross Sea (Antarctica) as a case study. PALEOSTRIP has been designed to be modular and to allow users to insert their own implementations.

Seismic surveys allow estimating lithological parameters, as P-wave velocity and anelastic absorption, which can detect the presence of fracture and fluids in the geological formations. Recently, a new method has been proposed for high-resolution imaging of anelastic absorption, which combines a macro-model from seismic tomography with a micro-model obtained by the pre-stack depth migration of a seismic attribute, i.e., the instantaneous frequency. As a result, we can get a broadband image that provides clues about the presence of saturating fluids. When the saturation changes sharply, as for gas reservoirs with an impermeable caprock, the acoustic impedance contrast produces “bright spots” because of the resulting high reflectivity at its top. When the fluid content changes smoothly, the anelastic absorption becomes a good detector, as fluid-filled formations absorb more seismic energy than hard rocks. We apply this method for imaging the anelastic absorption in a regional seismic survey acquired by OGS in the Gulf of Trieste (northern Adriatic Sea, Italy).

In recent years, new approaches for developing earthquake rupture forecasts (ERFs) have been proposed to be used as an input for probabilistic seismic hazard assessment (PSHA). Zone- based approaches with seismicity rates derived from earthquake catalogs are commonly used in many countries as the standard for national seismic hazard models. In Italy, a single zone- based ERF is currently the basis for the official seismic hazard model. In this contribution, we present eleven new ERFs, including five zone-based, two smoothed seismicity-based, two fault- based, and two geodetic-based, used for a new PSH model in Italy. The ERFs were tested against observed seismicity and were subject to an elicitation procedure by a panel of PSHA experts to verify the scientific robustness and consistency of the forecasts with respect to the observations. Tests and elicitation were finalized to weight the ERFs. The results show a good response to the new inputs to observed seismicity in the last few centuries. The entire approach was a first attempt to build a community-based set of ERFs for an Italian PSHA model. The project involved a large number of seismic hazard practitioners, with their knowledge and experience, and the development of different models to capture and explore a large range of epistemic uncertainties in building ERFs, and represents an important step forward for the new national seismic hazard model.

In this study, we present a comparative analysis between two types of gravity data used in geophysical applications: satellite altimeter-derived gravity and sea-bottom gravity.It is largely known that the marine gravity field derived from satellite altimetry in coastal areas is generally biased by signals back-scattered from the nearby land. As a result, the derived gravity anomalies are mostly unreliable for geophysical and geological interpretations of near-shore environments.To quantify the errors generated by the land-reflected signals and to verify the goodness of the geologic models inferred from gravity, we compared two different altimetry models with sea-bottom gravity measurements acquired along the Italian coasts from the early 50s to the late 80s.We focused on the Gulf of Manfredonia, located in the SE sector of the Adriatic Sea, where: (i) two different sea-bottom gravity surveys have been conducted over the years, (ii) the bathymetry is particularly flat, and (iii) seismic data revealed a prominent carbonate ridge covered by hundreds of meters of Oligocene-Quaternary sediments.Gravity field derivatives have been used to enhance both: (i) deep geological contacts, and (ii) coastal noise. The analyses outlined a “ringing-noise effect” which causes the altimeter signal degradation up to 17 km from the coast.Differences between the observed gravity and the gravity calculated from a geological model constrained by seismic, showed that all datasets register approximately the same patterns, associated with the Gondola Fault Zone, a major structural discontinuity traversing roughly E-W the investigated area.This study highlights the importance of implementing gravity anomalies derived from satellite-altimetry with high-resolution near-shore data, such as the sea-bottom gravity measurements available around the Italian coasts. Such analysis may have significant applications in studying the link between onshore and offshore geological structures in transitional areas.

This study is a contribution to the reconstruction of the geomorphology and the glacial history of the northern Victoria Land coastal glaciers. High-resolution single-channel reflection seismic lines were collected in 2002 within the framework of the Italian Antarctic programme (PNRA), in Wood Bay and Lady Newnes Bay, north to Cape Washington (western Ross Sea, Antarctica). The data provide evidence of overdeepened marine subglacial valleys, more than 1 km deep and 1–2 km wide, formed along the seaward extension of the Tinker, Aviator, Fitzgerald and Icebreaker glaciers and converging into the major SW–NE ice stream system. The spatial distribution and the geometry of the seismic facies, as well as the direct correlation with the seismic sequences in the Northern Basin, are interpreted to document 1) the depositional activity of a coastal glacial system seaward of northern Victoria Land (NVL) after 18 Ma (based on the seismic correlation with the base of DSDP 273) and possibly in the early Pliocene, in coalescence with expanded ice streams coming from the south along the Drygalski Basin, possibly draining from the WAIS as documented at AND-1B in the McMurdo Sound (Naish et al., 2007, 2008, 2009), followed by 2) the development of TAM tidewater glaciers that carved sea valleys near the Victoria Land coast, onto the shelf. The transition from a dynamic thick ice sheet covering the coastal area of NVL to the NVL valley glaciers advancing and retreating up to about 100 km from the coast in the middle Pliocene would represent a significant environmental change, possibly from interglacial conditions more temperate than today and gradually cooling to a cold and dry coastal regime.

The analyses of about 800 km of Chirp sub-bottom profilers and 600 km2 of Multibeam data acquired during the 2005 and 2007 surveys of the R/VOGS Explora, and their correlation with one new, and several public, multichannel seismic profiles, allow us to propose a relation between the distribution of gas seepages, fracture systems and deep salt features present in the Central Adriatic Sea. Gas seepage is evident from pockmarks on the seabed and in the shallow sub-bottom, where acoustic chimneys and bright spots have been highlighted and analyzed. The Mid-Adriatic Depression (MAD) is a distinct morphological feature in the Central Adriatic Sea elongated in a NE-SW direction. The area is affected by salt doming of Triassic evaporites which cause the two main alignments of the Mid-Adriatic Ridge as far as the Palagruza High and the Jabuka Ridge. These salt tectonics have existed since, at least, Paleogene times and are still active: they characterize sectors with less resistance to deformation produced by successive regional compressive regimes that have affected the area differently during the different geodynamic phases. Gas- seep features are distributed preferentially above and along the fracture systems produced above and around the salt mounds.

The paper aims to describe and map the geomorphological and lithological features of the Gulf of Trieste and its eastern coasts and to define its neotectonic behaviour by means of the analysis of the morphoneotectonic evidence. The final map, produced at a scale of 1:30,000, shows the outcome of field investigations carried out along the coast and the sea bottom and a detailed geomorphological classification of the coastline. Published and new data coming from the analysis of archaeological remains, geomorphological and sedimentological sea-level indicators and geophysical researches are discussed in order to provide a complete overview of the study area.

Late Pleistocene and Holocene palaeoenvironmental changes were studied in four gravity cores up to 7.8 m long from the Pennell Trough, a NW–SE-trending basin 160 km long and 60 km wide in the central Ross Sea, Antarctica, with depths occasionally greater than 600 m. Differences in environments and depositional processes during the last glacial and postglacial epochs were investigated using X-rays and volume magnetic susceptibility (VMS). Further analyses included bulk and clay mineral composition, micropalaeontological studies (both benthic and planktic foraminifera) and radiometric dating. We compare our sedimentological, geochemical (organic carbon and nitrogen content), and geotechnical (shear strength and water content) results to those on cores previously taken from the region. These analyses suggest that prior to the Last Glacial Maximum (LGM), a glacial marine diamicton (

The Wilkes Land continental rise is characterised by mounds and channels with approximately a north–south elongation, perpendicular to the margin. Proximal mound relief is up to 1000 m, decreasing to about 300 m in the central part. During the geophysical and geological survey conducted on in February–March 2000 by the joint Italian and Australian WEGA Project, onboard R/V Tangaroa, 11 piston cores were collected along two transects crossing the channel-mound system. All cores were logged for physical (magnetic susceptibility and density) and acoustic properties (P-wave velocity). Split cores were X-rayed and samples were analysed for clay mineral assemblages, chemical and micropaleontological (diatoms, foraminifera and nannofossils) content. Glacial and interglacial intervals have been recognised in the sediment cores. The interglacial facies consists of massive mud, distinguished by: (a) bioturbated massive mud occasionally with fine-grained ice-rafted debris (IRD), and (b) structureless massive mud with abundant fine to coarse-grained IRD, containing well-preserved open-ocean diatoms. The glacial facies is represented by laminated mud with planar and/or cross laminations, with occasional isolated dropstones, and rare, poorly preserved, sea-ice diatoms. The sharp boundary, characterizing the limit between massive to laminated facies, is interpreted to indicate a fast glacial onset. In contrast, the smooth passage presents from laminated to massive sediments, indicates a gradual glacial waning. Recent down-slope gravity flows have been identified in a turbidite, a normally graded coarse-grained sand, recovered in the thalweg of Jussie Canyon, and probably also in the massive debris facies from the steep side of Mound A. The massive debris is characterised by structureless and unsorted gravel and pebbles within a muddy matrix. Clay mineral assemblages and grain lithologies indicate a hinterland Wilkes Basin and continental shelf provenance for the terrigenous fraction.

Climatically controlled glaciological and oceanographic environmental changes off the George V Coast during the Late Pleistocene and Holocene have been reconstructed from changes in sedimentation processes. The evolution of a sediment drift deposit (Mertz Drift) located in the deep trough on the shelf has been assessed using a sedimentological approach. Up to 5.5 m long cores have been collected. Four Late Pleistocene to Holocene sediment units have been distinguished on the basis of their physical properties, grain-size distributions, geochemical characteristics and ages. The basal Unit 1 is a grey, sandy clayey diamicton (27–37 wt% sand) deposited before 14,000 14 C yr before present ( 14 C yr BP). Unit 1 represents a Late Pleistocene, sub-ice shelf water-lain till, overlain by a thin current-winnowed sandy sub-unit. Unit 2 is a massive siliceous sandy mud (11–30 wt% sand), rich in ice-rafted debris, deposited between about 14,000 and 5000 14 C yr BP. It likely represents an open-marine setting, proximal to a retreating ice-front, where strong bottom currents were frequent. The overlying Unit 3 is a laminated siliceous mud and diatomaceous ooze, with less terrigenous material (4–5 wt% average sand), deposited between 5000 and 3000 14 C yr BP. The low wet bulk density values ( 3 ) and mass-specific magnetic susceptibility values ( −8 m 3 /kg) of sediments of Unit 3 are a consequence of the high content of biogenic material (C org content >1 wt%; biogenic opal averaging 55 wt%). Unit 3 is probably related to a phase of increased sediment accumulation on the drift site and low bottom current activity on the shelf, with a stratified upper water column that could have lead to an enhanced primary productivity. Occurrence of crossed lamination indicates episodes of slightly enhanced bottom currents, probably with velocities up to 3–5 cm/s. The top Unit 4 is a bioturbated siliceous sandy mud, on average 50 cm thick, deposited under an energetic bottom current regime after about 3000 14 C yr BP. This regime is probably related to the activation of a brine-rejection mechanism and is linked to the formation of high-salinity shelf water (HSSW) in a coastal polynya, which causes winnowing of the shelf deposits. In contrast, the mid-Holocene setting was characterised by weaker bottom currents that, together with high inputs of organic material from the photic zone, allowed for the deposition of thick fine-grained sediments of Unit 3, resulting in an anoxic environment.

A late Quaternary, current-lain sediment drift deposit over 30 m in thickness has been discovered on the continental shelf of East Antarctica in an 850 m deep glacial trough off George Vth Land. Radiocarbon dating indicates that a period of rapid deposition on the drift (averaging 290 cm/kyr) occurred in the mid-Holocene, between about 3000 and 5000 yr before present. Slower rates of around 10 cm/kyr, during the past 0-3000 yr and from 5000 to about 13000 yr BP, coincides with deposition of bioturbated, ice-rafted debris (IRD) rich, sandy mud under an energetic bottom current regime. In contrast, the mid-Holocene (3000-5000 yr BP) sediments are fine-grained, laminated to cross-laminated with minimal IRD content, and are contemporaneous with a period of warmer marine conditions with less sea ice production. This pattern suggests that bottom currents were weaker than present day in the mid-Holocene, and that the rate of dense bottom water production was reduced at that time. This scenario is consistent with the hypothesis of non-steady state rates of Antarctic bottom water production through the Holocene as recently proposed by Broecker and his colleagues.

In this study, we investigate the thermo-mechanical controls on the formation of the Ross Sea basin (Antarctica) and the uplift of the adjacent Transantarctic Mountains (TAM) rift shoulder, which started in the Late Cretaceous and continued until the present time. Quantitative forward modelling has been performed along three 700 to 800 km long East–West offshore profiles, extended inland to the front of the TAM. The modelling is constrained by an extensive database of multichannel seismic (MCS), refraction seismic, Ocean Bottom Seismographs (OBS), and gravity data. MCS data is tied to well stratigraphy from DSDP leg 28, CIROS-1 and MSTSS-1. Quantitative estimates of uplift of the TAM are provided by previous work on apatite fission track analysis. We incorporate the finite strength of the lithosphere in basin formation models using the concept of the level of necking. Lateral variations of necking level and associated bulk rheological properties (with necking levels ranging from 15 km in the northernmost, to 20 km in the central and 23 km to the southernmost profiles) are required to explain the observed crustal geometries. High values of effective elastic thickness (more than 30 km) and pre-rift lithospheric thicknesses (220–230 km), indicating a cold lithosphere in a pre-rift cratonic setting, are consistent with elevation of the rift shoulder. The western parts of the profiles appear to have unusually high stretching values without the development of oceanic crust. Inferred average values of stretching factors vary from 2.3 to 2.8, equivalent with extension in the Ross Sea of 115% to 140%. The modelling result for the uplift of the TAM predicts a late Cretaceous tectonic uplift of about 1.5 to 2.0 km, and a Cenozoic uplift of about 1.3 km restricted to southern Victoria Land.

The Ross Sea region of the East Antarctic plate provides evidence for intraplate tectonic activity in Cenozoic times. Still unresolved are the cause, timing and kinematics of this intraplate tectonism. By integrating and discussing the different (kinematic and temporal) signals of Cenozoic tectonism, intraplate dextral shearing is recognized as the main tectonic regime controlling the structural architecture of the Ross Sea region from the Mid-Eocene (c. 40–50 Ma) onward. We speculate that propagation and persistence of this tectonic regime through time constitutes a feasible seismogenetic framework to explain past and current tectonism in the Ross Sea region.

The Victoria Land Basin is the westernmost branch of the Ross Sea rift system. It runs parallel to the Transantarctic Mountains which experienced 5 km of uplift during the Cenozoic. Several subbasins, with more than 6 km of Cenozoic sedimentary fill, were formed along the Victoria Land Basin during the same period. The analysis of multichannel seismic profiles suggests that a large transcurrent system runs along the Lee Arch, at the center of the Victoria Land Basin, which separates the Discovery Graben from the eastern basins. As a result, large asymmetric basins have developed here. They are bounded on one side by the transcurrent fault system and on the other side by normal faults. This structural situation is similar to other large sedimentary basins along continental transforms where transform-normal extension takes place. Previous studies pointed out the strike-slip nature of the Victoria Land Basin. In the present study we propose the Transform-Normal Extension model as the best mechanism to explain the observed structural features and the reconstructed evolution.

[1] We present seismic evidence of the presence of gas hydrates and free gas in Victoria Land Basin (western Ross Sea, Antarctica). The occurrence of gas hydrates is inferred from a bottom simulating reflector (BSR), the first identified in the Ross Sea area. The gas presence was analyzed through targeted reprocessing of the multichannel seismic reflection data (3000 m streamer, 120 channels, 60-fold) acquired in 1990 by the Italian R/V OGS-Explora. The seismic data were reprocessed in order to increase the signal-to-noise ratio by adopting a true-amplitude approach, allowing a subsequent amplitude variations with offset (AVO) analysis to extract information on both P and S wave reflectivity. Along a profile from the deeper basin to an intrabasin structural high, the BSR evolves into crosscutting reflectors (CCRs) and enhanced amplitude reflectors (EARs). Locally, another seismic event is interpreted to be a second BSR (BSR0), identified about 150 m below the first BSR and is possibly related to the presence of a mixture of gases comprising methane and hydrocarbons with heavier molecular weight and therefore associated with a deeper hydrate stability zone. The presence of faults controls the upward gas migration, connecting the free gas zone below the BSR and the mud volcanoes and pockmarks on the seafloor. The modeling of the hydrate equilibrium zone shows that the observed BSR/BSR0 could be stable at the present pressure-temperature conditions.

A multidisciplinary approach has been used to evaluate Late Holocene relative sea level change along the eastern coast of the Gulf of Trieste. Published data, together with new 14 C dating, have been compared with predicted curves in order to evaluate the tectonic behaviour of the studied area. Observations derived from precise geomorphological, archaeological and sedimentological measurements dated from 10 ka cal., sampled at elevations ranging between −25 and +0.10 m. Tectonic rates range from 1.01 mm/y (Gulf of Trieste) and –1.99 mm/y (Villaggio del Pescatore), but are probably higher in the northwestern sector, where the elevation of post-Roman geomorphological markers is lower. A detailed surveying of notches, beachrocks, submerged shore platforms and the geological setting of the coastal area highlight the variability of tectonic subsidence, indicated by geophysical data collected in the central part of the gulf. Analyzed data indicate active tectonism. The tectonic setting of the northernmost sector is affected by the presence of strike-slip faults which cause differential downdrop of the shoreline, as suggested by significant increases of notch depths, ranging between −1.0 m and −2.7 m.

The Ross Sea region of the East Antarctic plate provides evidence for intraplate tectonic activity in 13 Cenozoic times. Still unresolved are the cause, timing and kinematics of this intraplate tectonism. By 14 integrating and discussing the different (kinematic and temporal) signals of Cenozoic tectonism, intraplate 15 dextral shearing is recognized as the main tectonic regime controlling the structural architecture of the Ross 16 Sea region from the Mid-Eocene (c. 40–50 Ma) onward. We speculate that propagation and persistence of this 17 tectonic regime through time constitutes a feasible seismogenetic framework to explain past and current 18 tectonism in the Ross Sea region.

An integrated study of onshore and offshore geology of the Ross Sea region (namely, Victoria Land, north of Ross Island, and the Ross Sea, Antarctica) has revealed a complex, post-Eocene tectonic framework. Regional NW-SE right-lateral, strike-slip faults are the outstanding feature of this framework and overprint an older Mesozoic extensional event, responsible for formation of N-S basins in the Ross Sea. The Cenozoic framework includes kinematic deformation and reactivation along the NW-SE faults, including formation of pull-apart basins, both positive and negative flower structures, and push-up ridges. N-S extensional faults are well developed between NW-SE faults and indicate E-W extension during the Cenozoic, produced by the NW-SE right-lateral strike-slip motion together with regional crustal extension. NNW-SSE compression, induced by the right-lateral, strike-slip kinematics, is indicated by locally inverted NE-SW faults and basins. The evolution, geometry, and location of the Rennick Graben and the Lanterman Range fit well into this model. Variations in the deformational style across the region can be linked to corresponding variations in the bulk crustal rheology, from brittle behavior in the west, to ductile deformation (at subseismic-scale resolution) near the Eastern Basin. A semibrittle region that favors N-S clustering of Cenozoic magmatic activity lies in between. In this region, Cenozoic volcanoes develop at the intersections of the NW-SE and the major N-S faults. The NW-SE faults cut almost continually from the Ross Sea to East Antarctica through lithospheric sectors with different rheology and thickness. At least two of the NW-SE faults correspond to older Paleozoic terrane boundaries in northern Victoria Land. The NW-SE faults link in the Southern Ocean with major transform faults related to the plate motions of Australia, New Zealand, and Antarctica.

The disastrous 1999 earthquakes in Turkey have spurred the international community to study the geometry and behavior of the North Anatolian Fault (NAF) beneath the Marmara Sea. While the area is considered mature for a large earthquake, the detailed fault geometry below the Marmara Sea is uncertain, and this prevents a realistic assessment of seismic hazards in the highly-populated region close to Istanbul. Two geological/geophysical surveys were recently conducted in the Marmara Sea: the first in November 2000 with the R/V Odin Finder, and the second in June 2001 with the R/V CNR-Urania. Both were sponsored and organized by the Institute of Marine Geology of the Italian National Research Council (CNR), in cooperation with the Turkish Council for Scientific and Technical Research (TUBITAK) and the Lamont-Doherty Earth Observatory of Columbia University Multi-beam bathymetry, multi-channel seismic reflection profiling, magnetometry high-resolution CHIRP sub-bottom profiling, and bottom imaging were carried out with a remotely operated vehicle (ROV). Over 60 gravity and piston cores were collected.

A seismic line acquired near Gorizia (NE of Italy) and long about 3.3 km was reprocessed and interpreted with the aim to investigate the buried geological structures and the tectonic of the area. The seismic profile well images the structures buried by the Quaternary alluvial deposits. In particular are well imaged the top of the flysch at about 100 m in depth and a dipping reflector from South to North that can be related to the limestone. The flysch outcrops in the south part of the seismic line in correspondence of the Farra hill., and is affected by compressional and transpressional tectonic deformation. Also tomographic inversion of refracted and diving waves was performed, allowing us to define the velocities of the alluvial deposits and of the flysh. Also the structural setting of the embricated thrusts are well imaged by the final velocity field obtained by tomographic inversion.