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Low Strain Rate regions (LSRrs), i.e., areas undergoing tectonic deformation at rates of 1 mm/yr or less, often host important cities and highly vulnerable anthropogenic assets, and due to their subdued topography and relatively infrequent seismicity, are often considered low seismic hazard areas. Despite this, infrequent but high-magnitude earthquakes in such regions suggest that identifying active structures in the LSRr is one of the primary challenges for both the scientific community and modern societies. In such regions, one of the main issues in identifying active faults is the lack of valuable outcrop data due to erosional/sedimentation rates overwhelming the fault deformation, causing the hidden morphological signature of the tectonic structures. This work proposes a multidisciplinary approach designed to detect active geological structures and their related deformation in such areas. Our approach consists of quantitative morphotectonic, offshore and onshore tectonostratigraphic and GNSS joint analyses. To test this approach, we selected as a natural laboratory the partially offshore northern Sicilian LSRr (southern Italy) in the coastal sector located between the two major cities of Palermo and Termini Imerese. This area includes the compressional structures of the northern sector of the Apennine-Maghrebian fold and thrust belt, presently accommodating the slow Africa-Europe plate convergence. The main results we achieved are 1) new evidence of active tectonic deformation in this region; 2) the 3D modelling of two NNW-trending active faults; 3) the slip rate of a segment of the westernmost of the two detected faults; 4) a newly recorded relative GNSS velocity field; 5) a new morphotectonic map and morphotectonic evolution model of the study area. Our multidisciplinary approach allowed us to shed new light on the active tectonic framework of a slowly deforming area that crosses the physical limit of the coastline.

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., Scientific Reports, 12 (1), ISSN:2045-2322

Low Strain Rate regions (LSRr), i.e., areas deforming at a 1 mm/yr rate or less, represent the most globally widespread areas that host important cities and high-vulnerable anthropogenic assets. The occurrence of infrequent but high-magnitude earthquakes suggests that identifying active structures in the LSRr is one of the primary challenges for both the scientific community and modern societies.In such regions, one of the main issues in identifying active faults is the lack of useful outcrop data due to the anthropogenic and climate overprinting of the faults morphological signature. In this work, we propose a multidisciplinary approach designed to detect active geological structures and their related deformation. To test this approach, we selected as a natural laboratory an LSRr located between two major cities of Sicily (southern Italy). This area lies into the northern sector of the Apennine-Maghrebian fold and thrust belt and its offshore prolongation.Our approach consists of quantitative morphotectonic, offshore and onshore tectonostratigraphic and GNSS joint analyses. The main achieved results are 1) the first evidence of active, shallow-sited, NNW-trending transpressive blind faults that extends partially offshore for about 30 km, which décollement levels located at about 3 and 1 km depth, respectively and their 3D model, 2) a morphotectonic evolution model, that represents where and how these geologic structures drove the landscape evolution of the study area. Finally, we highlight that only a multidisciplinary approach could be useful for detecting and parametrising active faults in slow deforming areas that cross the coastline physical limit.

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.

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.

A new series of triazolotriazines variously substituted at the C5 and N7 (5-25) positions was synthesized and fully characterized at the four adenosine receptor (AR) subtypes. In particular, arylacetyl or arylcarbamoyl moieties were introduced at the N7 position, which enhanced affinity at the hA(2B) and hA(3) ARs, respectively, when utilized on the pyrazolo-triazolopyrimidine nucleus as we reported in the past. In general, compounds with a free amino group at the 7 position (5, 6), showed good affinity at the rat (r) A(2A) AR (range 18.3-96.5nM), while the introduction of a phenylcarbamoyl moiety at the N7 position (12, 19, 24) slightly increased the affinity at the hA(3) AR (range 311-633nM) with respect to the unsubstituted derivatives. The binding profiles of the synthesized analogues seemed to correlate with the substitutions at the C5 and N7 positions. At the hA(2B) AR, derivative 5, which contained a free amino group at the 7 position, was the most potent (EC(50) 3.42microM) and could represent a starting point for searching new non-xanthine hA(2B) AR antagonists. Molecular models of the rA(2A) and hA(3) ARs were constructed by homology to the recently reported crystallographic structure of the hA(2A) AR. A preliminary receptor-driven structure-activity relationship (SAR) based on the analysis of antagonist docking has been provided.

Seismogenic fault models and active deformation ones coupled with models of both earthquake rate and earthquake probability were recently used in a time-independent modelling. The integration of models allows to estimates the magnitude, location, and likelihood of potentially damaging earthquake ruptures in regions with high natural seismic hazard. Improvements of these models imply the recognition of the spatial geometry of the larger, active faults, deemed to be the source of the most damaging future earthquakes. However, identifying active faults and calculating their geologic slip rates for deriving earthquake rates are not easy tasks in regions inaccessible to direct field studies like active offshore areas. To improve the ability to define seismogenic fault models and active deformation models in offshore areas, we aim to develop a geophysical/geological method that allows to (a) identify the spatial geometry of active faults and fault systems in coastal areas, and (b) deduce the average long-term slip rates and recurrence interval, displacement per event, and elapsed time since the last event along the fault plane. The approach consists of innovative combination of geological and geophysical dataset, sampling methodology and GIS based on morphometric analysis. Preliminary results of this multidisciplinary approach applied to the coastal area of north Sicily document active deformation in an on-land sector of the Sicilian Maghrebian Chain and in its off-shore prolongation. Here we present results concerning the Palermo-Termini Imerese coastal sector based on a combination of: 1) structural data, 2) high-resolution reflection seismic data, 3) time series of GNSS data of the permanent stations of Palermo, Partinico, Prizzi, and Termini compared to the IGS station of Noto, 4) morphometric analysis of high-resolution digital elevation data for the hydrographic basins of the Oreto, Eleuterio, Milicia, San Leonardo, Torto and Imera Settentrionale rivers, and 5) seismological data. In the area of the Capo Zafferano promontory, Pleistocene conglomerates and grainstones are affected by recent tectonic deformation. In particular, at two sites near the village of Porticello we observed two sets of N-S to NNW-SSE and NE-SW striking deformation bands. Both sets have an almost vertical dip and show mutual cross-cutting relationships, suggesting their contemporaneous development. The N-S to NNW-SSE striking set shows left-lateral strike slip kinematic. At place, the deformation bands affect also Upper Pleistocene (Tyrrhenian) bio-calcarenites. In the off-shore, a number of seismic units, bounded by unconformities, were identified on seismic lines. The unit of inferred late Pleistocene age appears to be folded and faulted. Faults generally have an inclination of ca. 50°, small displacements up to 10 m and are sealed by the unit of inferred post-LGM age. Only a limited number of these faults are observed moving ca. 3 km offshore towards the NE. The average values of the velocity vectors obtained for the Palermo, Partinico, Prizzi, and Termini Imerese stations are 4.55, 2.97, 2.96, and 2.15 mm/yr, respectively. The direction of the velocity vectors for all stations is oriented towards the IGS reference station of Noto. The relative displacements of the Termini Imerese, Partinico and Prizzi stations respect to Palermo station are most equal to 0.5 mm/yr. Also, the directions of vectors suggest a clockwise rotation. The drainage network analysis highlights that the trunk streams of Eleuterio and San Leonardo drainage networks are asymmetric towards SE and the absolute asymmetry are ~ 3 and ~ 2 km, respectively. On the contrary, the trunk streams of the Milicia, Torto and Imera Settentrionale rivers are asymmetric towards W-NW with an asymmetry ranging from 3.5 up to 4 km. The Oreto stream does not show any evidence of lateral shift. Hypsometric analysis shows two types of statistical distributions of elevation classes. The latter have a bi-modal distribution for the Eleuterio, Oreto and Torto basins while uni-modal for the Milicia and San Leonardo basins. Values of the hypsometric integral are ~ 0.4 for the Milicia, San Leonardo and Torto basins, ~ 0.5 for the Eleuterio basin and 0.35 for the Oreto basin. The study area has been struck in the past centuries by several significant earthquakes of I0 ≥ 6. Mainly low-to-moderate magnitude seismicity, instead, occurred in this sector in the more recent times, showing highest earthquake concentration in the Tyrrhenian off-shore of the study area with respect to the onshore sector. To furnish a first constraint on seismogenic sources lying in this area, we performed hypocenter location and focal mechanism computation of the seismicity that occurred in the last thirty years. Then, we jointly evaluated data and information coming from historical seismicity with the results obtained by the geophysical, geological, and seismological analyses performed in order to better characterize the possible seismogenic sources present in the study region.