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The eastern Mediterranean is shaped by the interaction between the African, Arabian, and Eurasian plates resulting in a complex tectonic framework. The Hellenic subduction is well documented and studied but, the northeast corner of the eastern Mediterranean Sea remains enigmatic. It is a tectonically active region where different plate boundary conditions coexist (i.e., oceanic subduction, continental collision, extension, and strike-slip movements). An active and tsunamigenic system has been interpreted west and east of Cyprus by using deep seismic reflection lines. Vintage deep-penetrating seismic reflection profiles of the Mediterranean Sea project (MS project) - acquired during the ’70 - were re-analyzed and merged with a synthesis of available subsurface data from the scientific literature. This study focuses on two transects (MS53 and MS56) that cross the major offshore structures (i.e., Florence Rise, Latakia Ridge, and Kyrenia Ridge) from north to south. The western transect (MS53) shows the Herodotus oceanic crust subducting northward beneath the Eurasian plate. The Florence Rise is the leading edge of the system, and the Antalya Basin is its forearc basin. Close to the Turkish coast, a buried block seems to act as a backstop for the offshore system, and north of it, some out-of-sequence thrusts have been interpreted. The strain is partitioned between the Florence Rise and the Taurides front. The eastern transect (MS56) crosses the Latakia Ridge, i.e., the northern boundary of the Levant Basin, where shortening is greater than in the western area. The seismic line continues northward into the Cyprus – Latakia Basin, crossing the Kyrenia Ridge, and reaching the Turkish coast. On the seismic section, we interpreted the Mesozoic subduction front now hindered by strike-slip movements on the Latakia Ridge. Another prominent transpressive structure is the Kyrenia Ridge, which is interpreted as an active structure with a well-imaged thrust system in front of it. The seismic sections were depth converted to provide a regional geologic model for the northeastern Mediterranean Sea. Active subduction fronts, which are only partially imaged, were structurally modeled and then crosschecked with previous studies to better constrain their geometry. In the northeastern Mediterranean Sea, a plate boundary is buried offshore with active subduction west of Cyprus and mainly transpressional tectonics to the east. A better understanding of its nature and kinematics would be useful to assess the tsunami hazard in this area.

Well-preserved SSE-dipping low-angle normal faults (LANF) active during the Early Permian (Cisuralian) were recognized along the northern margin of the Orobic Basin (central Southern Alps, N Italy). These faults, which escaped most of the Alpine deformations, exhumed the Variscan basement during the deposition of the upper part of the Lower Permian succession (Pizzo del Diavolo Formation). Fault planes show evidence of frictional processes typical of the upper crust associated with hydrothermal circulation, responsible for the deposition of cm to m thick tourmalinite and Uranium mineralization. The recognized LANFs interacted with high-angle normal faults producing half grabens that stored the Lower Permian deposits, where synsedimentary fault activity in their hangingwall is testified by abrupt vertical and lateral facies changes, thickness variations and by soft-sediment deformations. Mesoscopic structures, exposed in the hangingwall of a major LANF (the Aga-Vedello Fault system) along a synthetic high-angle normal fault, include conjugate normal faults, horst-and-graben, domino-style planar and listric faults, which clearly record synsedimentary deformations testified by liquefaction and dewatering structures, typical of pre-consolidation hydroplastic conditions. This xceptional record indicates deformations at shallow crustal level which occurred during the Early Permian along highangle normal faults soling into the LANFs, forming the northern boundary of the Orobic Basin. The outcrop continuity, the perfectly preserved relationships among high- and low-angle normal faults together with the synsedimentary record of fault activity and the occurrence of mesoscopic faults developed during the deposition of the sediments, make this case-study an excellent reference for the analysis of extensional tectonics in synsedimentary conditions. In addition, the occurrence of large LANF systems, typical of a stress regime characterized by a vertical σ1, suggests that the Lower Permian Orobic Basin was dominated by pure extension at least in the study area, alternatively to existing interpretations, which favor a transtensional origin of the basin. Strike-slip tectonics can be responsible for a later partial tectonic inversion of the basin, as testified by the angular unconformity with the overlying Upper Permian succession (Verrucano Lombardo), marking a Middle Permian stratigraphic gap.

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.

The present‐day tectonic setting of the Eastern Mediterranean Sea results from a long deformation history, characterized by an alternation of extensional and contractional phases: from Mesozoic rifting to Late Cretaceous-present-day compression. This study focused on the tectonic reconstruction of the north-eastern side of the Mediterranean Sea, on a sector located between the Turkish coast and the northern Levantine Basin, using seismic reflection profiles. Previous studies dealt with the recent (Neogene) evolution because they did not have enough depth of investigation to recognize deeper reflections. We used vintage data such as MS and Strakhov surveys to analyze the deeper part of the area. We interpreted and depth-converted these seismic data, and we developed a sequential restoration to reconstruct the stratigraphic and structural evolution of the study area. In general, from north to south, we recognize the Cilicia Basin: a piggy-back basin bordered to the south by the offshore continuation of the Kyrenia Range. The Kyrenia Range is a positive flower structure generated during a transpressional phase because of the rotation of the Arabic plate. Southward, a secondary contractional system with an onlapping wedge is present in the area between the Kyrenia Range and another prominent ridge, i.e. the Larnaca Ridge. In the southern part, the same transpressional phase that generated the Kyrenia Range led to a positive inversion of an ancient extensional system, i.e. the Latakia Ridge. Beyond these positive flowers, the Levantine Basin is affected by extensional structures showing weak positive reactivation, including halokinetic features.In summary, we found that the inherited extensional structures strongly impacted the following contractional ones affecting both their geometry and their kinematics.

The Adriatic basin represents one of several restricted basins located in the Mediterranean Area. It consists of the foreland of three different orogenic belts: the Dinarides to the East, active during the Eocene, the Southern Alps to the North, active since the Cretaceous time, and the Apennines to the West, active since the Paleogene. The Apennines had a primary role during the Messinian Salinity Crisis (MSC), conditioning the connection between the Adriatic basin, the Ionian basin, and the proto-Tyrrhenian basin. During the Messinian, the present Adriatic Sea was characterized by shallow water domains, where gypsum evaporites initially deposited and often successively incised or outcropped. In the past 50 years, a massive dataset, composed of 2D multichannel seismic data and boreholes, was collected, covering almost the whole Adriatic basin in the Italian offshore. In this work, we interpreted the Plio-Quaternary base (PQb), based on available public datasets and on seismic profiles present in literature, which provided regional information from the northernmost Trieste Gulf (Northern Adriatic Sea) to the Otranto Channel (Southern Adriatic Sea). Here, we propose the PQb time-structural map, obtained by analyzing more than 600 seismic profiles. The PQb represents both the Messinian erosion and/or the top of the Messinian evaporites. It is characterized by a high-amplitude reflector, commonly called “horizon M” in the old literature. Principal findings concerning the Messinian event are summarized as below: -The Northern Adriatic (Gulf of Trieste, Gulf of Venice, Po delta, Kvarner Area) reveals widespread channelized systems produced by the initial decrease of the sea level, followed by subaerial erosion, related to further sea level decrease. High-grade erosion involved the nearby Adriatic carbonate platform in the Croatian offshore, where deep valleys, filled with Last Messinian or post- Messinian sediments, cut through the limestones.-The Central Adriatic (from the Po delta to the Gargano Promontory) displays a higher evaporites accumulation than the northern sector. Meanwhile, the Mid-Adriatic Ridge was already developing, along with the Apennine Chain, which was in a westernmost position. Erosional features in the deeper area are related to channelized systems, which followed the evaporites deposition. Meanwhile, also the Mid-Adriatic Ridge was affected by erosion.-The Southern Adriatic (from the Gargano Promontory to the Otranto Channel) is characterized by the Mesozoic Apulia carbonate platform, covered by a thin Cenozoic sequence affected by subaerial erosion or non-deposition. The platform margin and the slope leading to the deepest South Adriatic basin, where a Messinian gypsum layer, also recorded in the Albanian and Croatian offshore, shows a lower level of upper erosion.In general, we notice strongly variable thicknesses of the horizon M, which is related to submarine erosion (channels), subaerial erosion (discontinuous surfaces), non-deposition (possible unconformity), and tilting toward the surrounding chains (deepening horizons). In this work, we evaluate these different components from a regional point of view.

The Plio-Quaternary tectonic evolution of the central sector of the Sicilian Channel and the resulting morphostructural setting have been analyzed using a large geophysical dataset consisting of multichannel seismic profiles, which some of them never published, and available bathymetric data. This area hosts two regional-scale tectonic domains that registered the complex pattern of deformation occurred since the Early Pliocene: (1) the Sicilian Channel Rift Zone (SCRZ), which can be divided into a western sector formed by the Pantelleria graben (PG) and in a eastern one represented by the Linosa and Malta grabens (LG and MG) and (2) the Capo Granitola-Sciacca Fault Zone (CGSFZ), a NNE-oriented lithospheric transfer zone that crosses the Sicilian Channel from the Sicily coast to the Linosa Island, of which only its northern part has been studied to date. Data interpretation has allowed achieving the following outcomes: (i) the presence of an alternation of basins and structural highs forming a NNE-oriented separation belt between the western and eastern sectors of the SCRZ, and interpreted as the shallow expression of the southern part of the CGSFZ; (ii) a NE-oriented tectonic lineament separating the MG in a northern and southern part, and interpreted as the southern prosecution of the Scicli-Ragusa Fault System; (iii) the presence of syn-rift deposits in the Plio-Quaternary fill of the grabens, suggesting that the opening of the grabens of the SCRZ was coeval, and started since Early Pliocene in the framework of a NW-oriented right-lateral transtensional mega-shear zone; (iv) continental rifting ended around the Early Calabrian, during which extensional tectonics dominated along the separation belt; (v) the CGSFZ conditioned the SCRZ configuration at a regional scale, leading to the development of the PG in the western sector and of the LG and MG in the eastern one; and (vi) after the Early Calabrian, the PG and the southern MG followed a different tectonic evolution with respect to the LG and northern MG. The syn-rift deposits of the PG and southern MG were sealed by an undeformed post-rift succession, while the LG and the northern MG suffered a basin inversion that ended around the Latest Calabrian time. During this stage, the separation belt was affected by a transpressional tectonics. At present, the grabens of the Sicilian Channel seem to be tectonically inactive, while the CGSFZ represents an active tectonic domain.

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.

Nowadays depth imaging of seismic data, using different migration schemes (rays tracing or waves equation methods) and different techniques for velocity model building (i.e. grid or layer-based tomography, isotropic or anisotropic velocity field) is a standard approach for the earth’s subsurface characterization. When dealing with low fold vintage data, acquired with outdated technologies, modern processing algorithms may fail. On the other hand, the reprocessing of these old data with modern techniques may lead to an improvement of quality and resolution, allowing a more accurate interpretation of the investigated geological features. It is important to note that a lot of vintage data were acquired in areas with no recent surveys or currently subject to exploration restrictions. Therefore, available vintage data could be of great importance for all the stakeholders involved in geophysical exploration. We present a case study about the reprocessing of low fold marine seismic data that were acquired in 1971 in the Otranto Channel (Southern Adriatic Sea, Italy).The first part of the work consists of a modern broadband sequence processing in the time domain, that allowed us to obtain a pre-stack time migrated seismic section; in the second part, depth imaging has been achieved through a pre-stack depth migration (PSDM). Reliable interval p-waves velocity model has been obtained using two tomographic approaches: grid tomography and layer-based tomography; for both, we carried out several iterations of the refinement loop, consisting of migration, ray tomography, residual velocity analysis, velocity model update.The results show significant improvements compared to the original vintage section, in terms of resolution and signal to noise ratio. Moreover, depth imaging and velocity modeling added further information (e.g., reliable interval p-waves velocity model, real geometry and thickness of the main geological units). This study confirms that applying the up-to-date processing and imaging techniques to vintage data, their geophysical and geological value is enhanced and renewed at a relatively low cost.

Two models with different area and 3D volumetric grid size dimension of the E6 oil-bearing structure were built. The bigger model should allow visualization of complete migration of CO2 plume within the developed 3D grid model using fluid-flow simulation (cell size 500 m). The smaller model is focused on the uppermost part of the Cambrian Series 3 Deimena Formation reservoir close to the drilled well, assuming that CO2 injection will take place in this area. The model with a finer gridding (cell size 30 m) was adopted for seismic numerical modelling. The grid size of this in the model was reduced as much as possible to satisfy seismic modelling needs.

Pilot project for CO 2 storage and CO 2 -EOR/EOR+ in different geological formations including two scenarios is proposed for Latvian offshore structure E6. The first “two wells and possible fault-leakage” scenario proposed CO 2 storage in the Cambrian Deimena Formation and oil recovery from the Upper Ordovician Saldus Formation. One common injection well and possible fault leakage to the oil reservoir are considered as a profit. The second “three wells and no leakage” scenario, includes additional CO 2 injection well to oil reservoir. A surplus for both scenarios is increased CO 2 storage capacity. The new pilot project idea supports exploitation of small oil deposits in the Baltic Region.

The Northern Adriatic Sea is a shallow and very flat shelf area located between the northern Apennines, the southern Alps and the Dinarides; its present day physiography is the result of the filling of a relatively deep Quaternary foredeep basin, developed due to the northeastward migration of the Apennine chain. Multichannel seismic profiles and well data have allowed documenting the stratigraphic architecture, the depositional systems and the physiographic evolution of the Northern Adriatic sea since early Pliocene time. In particular, three main depositional sequences bounded by regional unconformities were recognized. The Zanclean Sequence 1 documents first the drowning of late Messinian incised valleys and then the southward progradation of a shelf-slope system, which is inferred to be related to a tectonic phase of the Apenninic front. The Piacenzian-Gelasian Sequence 2 records a relatively rapid transgressive episode followed by minor southward progradation; the top of the sequence is associated with a major late Gelasian drowning event, linked to the NE-ward migration of the Apennine foredeep. The Calabrian to upper Pleistocene Sequence 3 testifies the infilling of accommodation previously created by the late Gelasian drowning event, and it initially accumulated in deep-water settings and then in shallow-water to continental settings. The upper part of Sequence 3, consisting of the paleo-Po deltaic system, is composed of seven high-frequency sequences inferred to record late Quaternary glacio-eustatic changes. These high-frequency sequences document the stepwise filling of the remaining accommodation, resulting in the development of the modern shelf.

We conduct the seismic signal analysis on vintage and recently collected multi-channel seismic reflection profiles from the Ionian Basin to characterize the deep basin Messinian evaporites. These evaporites were deposited in deep and marginal Mediterranean sedimentary basins as a consequence of the “salinity crisis” between 5.97 and 5.33 Ma, a basin‐wide oceanographic and ecological crisis whose origin remains poorly understood. The seismic markers of the Messinian evaporites in the deep Mediterranean basins can be divided in two end‐members, one of which is the typical “trilogy” of gypsum and clastics (Lower Unit – LU), halite (Mobile Unit – MU) and upper anhydrite and marl layers (Upper Unit – UU) traced in the Western Mediterranean Basins. The other end‐member is a single MU unit subdivided in seven sub‐units by clastic interlayers located in the Levant Basin. The causes of these different seismic expressions of the Messinian salinity crisis (MSC) appear to be related to a morphological separation between the two basins by the structural re- gional sill of the Sicily Channel. With the aid of velocity analyses and seismic imag- ing via prestack migration in time and depth domains, we define for the first time the seismic signature of the Messinian evaporites in the deep Ionian Basin, which differs from the known end‐members. In addition, we identify different evaporitic deposi- tional settings suggesting a laterally discontinuous deposition. With the information gathered we quantify the volume of evaporitic deposits in the deep Ionian Basin as 500,000 km3 ± 10%. This figure allows us to speculate that the total volume of salts in the Mediterranean basin is larger than commonly assumed. Different depositional units in the Ionian Basin suggest that during the MSC it was separated from the Western Mediterranean by physical thresholds, from the Po Plain/Northern Adriatic Basin, and the Levant Basin, likely reflecting different hydrological and climatic conditions. Finally, the evidence of erosional surfaces and V‐shaped valleys at the top of the MSC unit, together with sharp evaporites pinch out on evaporite‐free pre‐ Messinian structural highs, suggest an extreme Messinian Stage 3 base level draw down in the Ionian Basin. Such evidence should be carefully evaluated in the light of Messinian and post‐Messinian vertical crustal movements in the area. The results of this study demonstrates the importance of extracting from seismic data the Messinian paleotopography, the paleomorphology and the detailed stratal architecture in the in order to advance in the understanding of the deep basins Messinian depositional environments., peer-reviewed

Source at https://doi.org/10.3301/IJG.2018.34. A multidisciplinary approach has been used for the first time to study the widespread occurrence of hydrocarbon seeps in the northern Adriatic Sea. Geological, geophysical and geochemical analyses were performed to identify and characterize the gas-charged fluids occurring throughout the Plio-Quaternary succession, and to date the shallow gas seeping at three leakage sites. The analysis of CHIRP, morpho-bathymetric, and multichannel seismic data allowed us to identify different types of gas-related features, which occur within the whole Plio-Quaternary succession up to the seafloor and to the water column. Quantitative analyses of CHIRP data were conducted to better define, characterize and quantify the gas occurrence within the uppermost stratigraphic succession. CHIRP data also allowed identifying the gas leakage sites. Three gas seepages areas were sampled with the aim to determine the gas composition and origin. The isotopic analyses revealed that seep gases are microbial in origin, and are primarily composed by methane, mostly formed within relatively laterally persistent Late Pleistocene peat layers, which are widely distributed throughout the northern Adriatic Sea and represent the main source of organic matter feeding the seeping gases.

The interpretation of approximately 1300 km of multichannel seismic data, acquired in the northern Adriatic Sea, revealed that the Apennine foredeep in the northern Adriatic does not show any evidence of tilting since Early Pliocene, suggesting that slab retreat cannot be the geodynamic driving force for the northern Adriatic subsidence and for the northern Apennine kinematic since that time. Moreover, the presence of two fault systems that developed since the Pliocene indicates that the northern Adriatic underwent intraplate deformation during the Plio-Pleistocene. These considerations suggest that, since Early Pliocene, subduction below the northern Apennine ceased, and that the Adria Plate movements were mainly driven by the kinematics of the adjacent plates, particularly by the Nubia-Europe convergence. At present, on the basis of the foredeep setting, four distinct sectors can be recognized in the Adriatic foreland: Po Plain, northern, central and southern Adriatic, separated by major tectonic lineaments. The northern Adriatic differs from the two adjoining sectors because its foredeep deposits are still well preserved. In the Po Plain in fact, the Adriatic foredeep is almost totally incorporated into the Alpine and Apennine chains while in the central Adriatic, it is affected by a considerable intraplate deformation (e.g. the Mid Adriatic Ridge). In this framework, the northern Adriatic region may be regarded as a triangular shaped sector indented below the Southern Alps to the north and the northern Dinarides to the north-east and bounded to the west by the Schio-Vicenza fault system and to the south-east by the Kvarner fault.

Time-lapse numerical seismic modelling based on rock physics studies was for the first time applied to analyse the feasibility of CO 2 storage monitoring in the largest Latvian offshore geological structure E6 in the Baltic Sea. The novelty of this approach was the coupling of the chemically induced petrophysical alteration effect of CO 2 -hosting rocks measured in laboratory with time-lapse numerical seismic modelling. Synthetic seismograms were computed for the E6 structure, where the sandstone reservoir of the Deimena Formation of Cambrian Series 3 (earlier Middle Cambrian) was saturated with different concentrations of CO 2 . The synthetic seismograms obtained after CO 2 injection were compared with the baseline. The following four scenarios were considered: (1) a uniform model without the alteration effect; (2) a uniform model with the alteration effect; (3) a plume model without the alteration effect; and (4) a plume model with the alteration effect. The presence of CO 2 in the reservoir layers can be detected by direct comparison and interpretation of plane-wave synthetic seismic sections, and is clearly observed when one displays the difference between the baseline and post-CO 2 injection synthetics. The normalized root-mean-square imaging techniques also clearly highlight the time-lapse differences between the baseline and post-injection seismic data. The laboratory-conducted alteration of the petrophysical properties of the reservoir had a strong influence on the reflected signals in the seismic sections. The greatest difference was revealed on seismic sections with 1% CO 2 saturation, increasing the detectability of the stored CO 2 . The difference decreased with an increase in CO 2 content. The saturation of CO 2 could be qualitatively estimated up to a value of 5%. Higher saturation produced a strong signal in the repeatability metrics but the seismic velocity varied so slightly with the increasing gas content that the estimation was challenging. A time shift or push-down of the reflectors below the CO 2 storage area was observed for all scenarios. According to changes in the amplitude and two-way travel times in the presence of CO 2 , reflection seismics could detect CO 2 injected into the deep aquifer formations even with low CO 2 saturation values. Our data showed the effectiveness of the implemented time-lapse rock physics and seismic methods in the monitoring of the CO 2 plume evolution and migration in the E6 offshore oil-bearing structure. The new results obtained could be applied to other prospective structures in the Baltic region.

Large amounts of vintage seismic data were rescued and disseminated in an internal project of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS). Such types of data would be very difficult to acquire today because they cover many areas that are currently subject to restrictions in obtaining exploration permits. The datasets extend over large geographical areas, covering large geological structures and would be very expensive to acquire today. Additionally, these data are particularly interesting because they were acquired using a high-energy source (dynamite) that would be difficult to obtain permission to use today. Therefore the recovery of these data could be very interesting for both the scientific and commercial communities. The urgency of rescuing tapes before degradation, and scanning and converting the paper sections into a usable form was the main focus, but, at the same time, the project looked ahead and attempted to address possible future exploitation of these data. To this end, considering how end users are likely to search for and use data, a full processing path that goes beyond recovery to consider other aspects was developed. The other concerns integrated into this process are • data enhancement, to overcome data limitations due to the older technology used during acquisition; • data integration, to consolidate different data types within the same data space, and • data discovery, for which a specific web based framework named SNAP (Seismic data Network Access Point) was developed that allows end users to search, locate and preview the data.

The Southern Adriatic Sea is one of the five prospective areas for CO2 storage being evaluated under the FP7 European Sitechar project. The potential reservoir identified in the investigated area is represented by a carbonate formation (Scaglia Formation – Late Cretaceous). This paper shows the site characterization applied to one of the structures identified in the carbonate storage system of the South Adriatic offshore. The interpretation and analysis of seismic and borehole data allowed the construction of a 3D geological static model on both regional and local scales. Dynamic modeling was applied, adopting a sensitivity approach (i.e. fault transmissivity, petrophysical properties of the caprock and reservoir, and different stress regimes). Coupled fluid flow and geomechanical simulation was applied to investigate the potential risk of leakage induced by mechanical solicitation on the faults occurring in the investigated area.

In the Northern Adriatic Sea, the occurrence of gas seepage and of unique rock outcrops has been widely documented. The genesis of these deposits has recently been ascribed to gas venting, leading to their classification as methane-derived carbonates. However, the origin of seeping gas was not clearly constrained. Geophysical data collected in 2009 reveal that the gas-enriched fluid vents are deeply rooted. In fact, the entire Plio-Quaternary succession is characterized by widespread seismic anomalies represented by wipe-out zones, and interpreted as gas chimneys. They commonly root at the base of the Pliocene sequence but also within the Palaeogene succession, where they appear to be associated to deep-seated faults. We suggest that there is a structural control on chimney distribution. Chimneys originate and terminate at different stratigraphic levels; commonly they reach the seafloor, where authigenic carbonate deposits form locally. Gas analyses of some gas bubble streams just above the rock outcrops reveal that gas is composed mainly of methane. Geochemical analyses performed at four selected outcrop sites show that these deposits formed as a consequence of active gas venting. In particular, geochemical analyses indicate carbonate precipitation from microbial oxidation of methane-rich fluids, although a straightforward correlation with the source depth of gas feeding the authigenic carbonates cannot yet be clearly defined.

Carbonate successions have a large distribution in the Italian territory, both onshore and offshore, and they are commonly hydrocarbons exploration targets. However, an evaluation of the suitability of these sedimentary successions for CCS projects has never been performed. The present study has allowed for the first time the recognition and the geological and structural characterization of areas potentially suitable for CO2 geological storage in carbonate rocks in Italy. To achieve this objective, public available well data and 2D multichannel seismic profiles were analyzed and interpreted, allowing to define eight areas (Malossa–San Bartolomeo, Lachiarella–Binasco, Abruzzi offshore, Abruzzo–Molise, Southern Adriatic, Northern Bradanic Trough, Southern Bradanic Trough, Sicily Channel) characterized by potential reservoirs in carbonate rocks sealed by relatively thick and laterally continuous caprocks. The present results have also highlighted marked spatial heterogeneities in the recognized reservoirs, inferred to result from primary depositional processes, diagenesis and fracturing due to tectonic events. Most reservoirs were recognized within shallow marine carbonate platform succession, among which the most suitable for CCS purposes are those composed of dolostones, showing maximum porosity and permeability values of 25% and 400–450 mD, respectively. Among the identified areas, the so called “Sicily Channel” and “Abruzzi offshore” are probably those most promising because of their location in offshore settings, closeness to significant sources of CO2 and distance from the main seismogenetic tectonic structures, as well as for the occurrence of one or multiple reservoir–caprock systems. However, the information provided by this study is at a regional scale, and therefore more detailed analyses are needed to identify and characterize potential individual storage sites for CCS projects.

In 2009, the National Institute of Oceanography and Experimental Geophysics (OGS, Italy) has performed a geophysical survey in the northernmost sector of the Northern Adriatic Sea, between the Tagliamento and Po river deltas, with R/V OGS Explora. About 820 km of 2D multichannel seismic and Chirp profiles, together with multibeam data along the ship tracks, have been acquired, with the aim to reconstructing the Plio-Quaternary stratigraphic and tectonic setting of the study area. Data have been also analyzed to verify whether this region is suitable for CO2 geological storage. Sites eligible for the application of Carbon Capture and Storage (CCS) techniques have been already identified in the Adriatic Sea, except in the northernmost sector, due to the scarcity of available data. The analyses of the new OGS seismic dataset highlighted the occurrence of peculiar seismic anomalies, represented by sub-vertical wipe-out zones, that have been interpreted as due to gas leakages affecting the Plio-Quaternary sequence. They could be possibly related to the formation of rock outcrops interpreted as methane-derived carbonates. It is suggested that gas migrates along sub-vertical chimneys throughout the Plio-Quaternary sequence. The correlation of these sub-vertical features among the seismic profiles reveals that two main alignments could be recognized: a NW–SE trend offshore the Venice Lagoon and a NE–SW in the northernmost part of the investigated area. It leads to hypothesize that the preferential conduits for gas migration are associated to tectonic lineaments. The analysis of the tectonic setting has been then addressed at defining the role of fault/fracture zones, which can affect the integrity of a CO2 storage complex in this area. Tectonic features have been identified in the Mesozoic–Paleogene succession, but their relationship with the shallow faults/fractures representing the paths for gas leakages still need further work and additional data in order to be clearly constrained.

The Ionian margins of Calabria are affected by repeated sediment failures, recorded by slide scars at seabed and stacked slide deposits. We present a reconstruction of the geometry and dynamics of one of the largest seabed features, the Assi failure on the relatively steep slope off southern Calabria, and use it as input to numerical modeling to evaluate the potential tsunamigenic hazard. The Assi failure is up to 6 km wide and at least 18 km long, and involved the displacement of ca. 2 km3 of sediment, inferred to have taken place within the last 4,000 years in two main phases. The first and larger phase is used as input to the tsunami modeling, on the assumption that the slide moved in a single step as a coherent mass of 1.85 km3, in order to evaluate the most disruptive possible consequences. The results indicate that within 8 minutes, waves just over 1 m in height affect the southern Calabrian coast between Monasterace and Roccella Jonica, where their capacity to cause damage could be amplified in small harbours. This shows that tsunamis represent a hazard for Ionian coastal areas, and calls for accurate monitoring and further study.

The Ionian margins of Calabria and Apulia (IMCA) have been affected by mass movements of varying style, scale and age. Here we present examples of seabed and subsurface features identified along more than 400 km of the IMCA from multibeam seabed imagery and subbottom profiles acquired by OGS since 2005. Four different types of mass movement phenomena are recognized with expression at seabed and in the shallow subsurface: (1) mass transport complexes (MTCs) within intra-slope basins, (2) isolated slide scars (ISS) along open slopes, (3) slope-parallel sediment undulations (SPSU) recording block-rotations linked to fluid migration, and (4) headwall and sidewall scarps (HSC) in submarine canyons. Preliminary analyses of sedimentary processes suggest that both open-slope failures capable of triggering tsunamis and retrogression of canyon headwalls within 1–3 km of the Calabrian coast represent potential geohazards for coastal populations and offshore infrastructures.

We analyse and compare the shear-wave velocity distribution obtained from multi-fold SH reflection data and from Rayleigh wave dispersion curve inversion. The analysis focuses on two seismic datasets from a waste disposal site. We use an optimisation scheme based on a Genetic Algorithm and on the evaluation of the Marginal Posterior Probability Density to invert the dispersion curves and handle the strong multi-modality of the inversion problem. The number of reflectors in the inversion process is constrained by the SH-wave reflection survey to allow better comparison of the results. The final velocity models, separately obtained by the two techniques, are in excellent agreement and are validated by the available borehole data. The results of the study demonstrate the benefits of joint shear and Rayleigh wave surveys with particular reference to media characterized by strong attenuation.

The Southern Adriatic Sea is one of the five perspective areas for CO2 storage being evaluated under the FP7 European SiteChar project. This site is the most challenging among those studied in this project, since the potential reservoir is hosted in a carbonate formation. In a first instance, the 3D geological static model at both regional and local scale, was constructed, based on the analysis and the interpretation of the available geological, geophysical and borehole data. Coupled fluid flow and geomechanical modeling has been also performed, through the simulation of various scenarios (i.e. open, closed or mid-opened faults, in situ different stress regimes). Dynamic modeling shows that CO2 injection-induced overpressure extends up to 30 km when faults are open, and that sealing capacity of the faults impacts the stress field and the propagation of the CO2 plume around the injection point. The site characterization procedure that has been applied on the Southern Adriatic offshore can be considered as an example that could be adopted when investigating reservoir carbonate formations, especially where crucial information for modeling are missing and need to be derived through an analytical approach.