ALBERT

Description: The surveillance of the Neapolitan volcanic area (Mt. Vesuvius, the Phlegrean Fields and the island of Ischia) represents the principal activity of the Osservatorio Vesuviano. Such an activity is carried out also through the study of ground deformations. This study deals with the use of the GPS as a powerful topographic technique. In the last two years, three GPS networks in the above mentioned area were established, with 8 vertices at Mt. Vesuvius, 20 vertices in the Island of Ischia and 30 vertices in the Phlegrean Fields. In Mt. Vesuvius area a GPS test was carried out, in order to verify the possibility of the installation of a network of GPS permanent stations. In the island of Ischia, three diferent GPS techniques (Static, Fast Static and RTK-Real Time Kinematics) have been used to get a first set of coordinates and to carry out a comparison between these in small extension areas. GPS data of the Phlegrean Fields are still in processing. The results for Mt. Vesuvius area and the island of Ischia are hereby presented and discussed.

Description: Osservatorio Vesuviano - Napoli, Italy DISTART - Università di Bologna, Italy Università della Calabria - Cosenza, Italy Dipartimento di Costruzioni e Trasporti - Università di Padova, Italy

Description: Published

Description: 705-711

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: We demonstrate a synchronous correlation technique to determine the chronology of Quaternary palaeoshorelines to test proposed relationships between tectonics, climate and sea-level change. The elevations of marine palaeoshorelines in Calabria around the active Vibo normal fault have been measured from TIN DEM 10 m data and fieldwork and correlated with global sea-level curves. A synchronous correlation method and new U/Th dates are used to ascertain how the slip-rate on the fault relates to uplift rates across the region. Regional uplift, possibly associated with subduction along the Calabrian trench or due to the cumulative effect of closely-spaced active normal faults, is rapid enough to uplift even the hangingwall of the Vibo normal fault; the actual value for the rate of background uplift can only be ascertained once the rate of slip on the Vibo fault is subtracted. Synchronous correlation of multiple palaeoshorelines sampled along 29 elevation profiles with global sea-levels shows that the resultant uplift rate (background uplift minus local hangingwall subsidence) is constant through time from 0 to 340 ka, and not fluctuating by a factor of 4 as previously suggested. The uplift rate increases from 0.4 mm/yr at the centre of the hangingwall of the fault to 1.75 mm/yr in the hangingwall in the vicinity of the fault tip. Palaeoshorelines can be traced from the hangingwall to the footwall around the fault tip and hence correlated across the fault. The throw-rate on the fault averaged over 340 ka decreases from a maximum at the centre of the fault (1 mm/yr) to zero at the tip. This gradient in throw-rate explains the spatial variation in resultant uplift rates along the fault. We interpret the 1.75 mm/yr resultant uplift rate at and beyond the fault tip as the signature of a regional uplift, presumably related to subduction, although we cannot exclude the possibility that other local faults influence this uplift; the lower uplift rates in the hangingwall of the fault are due to interaction between “regional” uplift and subsidence associated with the local active normal faulting. We discuss (a) how our synchronous correlation technique should trigger a re-appraisal of palaeoshoreline chronologies worldwide, and (b) the implications for the tectonics and seismic hazard of Calabria, suggesting that perturbations in the uplift-rate field are a key criterion to map the locations of active faults, their deformation rates, and hence seismic hazard above subduction zones.

Description: Published

Description: 169-187

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: The Cotentin Peninsula (Normandy, France) displays sequences of marine terraces and rasas, the latter being wide Late Cenozoic coastal erosion surfaces, that are typical of Western European coasts in Portugal, Spain, France and southern England. Remote sensing imagery and field mapping enabled reappraisal of the Cotentin coastal sequences. From bottom to top, the N Cotentin sequence includes four previously recognized Pleistocene marine terraces (T1 to T4) at elevations 〈 40 m as well as four higher and older rasas (R1 to R4) reaching 200 ± 5 m in elevation. Low-standing marine terraces are not observed in the central part of the Peninsula and a limited number of terraces are described to the south. The high-standing rasas are widespread all over the peninsula. Such strandline distributions reveal major changes during the Late Cenozoic. Progressive uplift of an irregular sea-floor led to subaerial exposure of bathymetric highs that were carved into rocky platforms, rasas and marine terraces. Eventually, five main islands coalesced and connected to the mainland to the south to form the Cotentin Peninsula. On the basis of previous dating of the last interglacial maximum terrace (i.e. Marine Isotopic Stage, MIS 5e), sequential morphostratigraphy and modelling, we have reappraised uplift rates and derived: (i) mean Upper Pleistocene (i.e. since MIS 5e ~ 122 +/− 6 ka, i.e. kilo annum) apparent uplift rates of 0.04 ± 0.01 mm/yr, (ii) mean Middle Pleistocene eustasy-corrected uplift rates of 0.09 ± 0.03 mm/yr, and (iii) low mean Pleistocene uplift rates of 0.01 mm/yr. Extrapolations of these slow rates combined with geological evidence implies that the formation of the sequences from the Cotentin Peninsula occurred between 3 Ma (Pliocene) and 15 Ma (Miocene), which cannot be narrowed down further without additional research. Along the coasts of Western Europe, sequences of marine terraces and rasas are widespread (169 preserve the MIS 5e benchmark). In Spain, Portugal, S England and other parts of western France, the sequences morphostratigraphy is very similar to that of Cotentin. The onset of such Western European sequences occurred during the Miocene (e.g. Spain) or Pliocene (e.g. Portugal). We interpret this Neogene-Quaternary coastal uplift as a symptom of the increasing lithospheric compression that accompanies Cenozoic orogenies.

Description: Published

Description: 338-356

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: This work describes the development of an underwater anti-intrusion system based on a magnetometer self-informed network, whose purpose is to detect the presence of threats in the proximity of critical infrastructures (e.g, terrorist divers in harbours). In this context, the magnetic network fills the gaps of sonar systems at the critical boundaries of the water volume to be controlled (sea bed, docks, …), where acoustic performances deteriorate due to reflections and attenuations. The system operates in a port-protection scenario, characterized by a medium-high environmental magnetic noise that can hide the diver signal (a diver is a weak, quasi-point-like, moving source). The magnetometer network processes two inputs: the environmental magnetic noise and a signal including the target magnetic signal superimposed to the same noise; the frequencies of a diver signal lie within the noise band, hence frequency filtering proves inadequate for noise removal. The basic idea underlying the system is to measure and use the noise itself to filter the overall signal; measuring noise supports a background-subtraction process that allows to extract the target signal and therefore detect the threat presence. The effectiveness of the procedure depends on the positions of magnetometers: sensors must be close enough to one another to measure the common background noise, and, at the same time, should be distant enough from one another so that just one sensor can measure the target signal. To generate alarms when a threat is detected, a real-time software application processes data and activates a visual and acoustic alarm upon identification of a magnetic anomaly. Sea trials carried out in port areas provided extremely satisfactory results in the detection of intruders. The paper presents experimental results obtained during the method validation tests, when intruders were moving in the surrounding undersea environment.

Description: Published

Description: 104743

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare

Description: 7SR AMBIENTE – Servizi e ricerca per la società

Description: JCR Journal

Description: The structure of a caldera may influence its activity, making its understanding crucial for hazard assessment. Here, we analysed high-resolution seismic profiles in the Campi Flegrei (southern Italy) offshore sector. We recognised two main fault systems, including those associated with the formation of the caldera and those affecting the resurgent dome. The former system comprises three broadly concentric fault zones (inner, medial and outer ring fault zones) depicting a nested caldera geometry. Considering the relations between faults and seismic units that represent the marine and volcaniclastic successions filling the caldera, all ring faults were formed during the Campanian Ignimbrite eruption (40 ka) and subsequently reactivated during the Neapolitan Yellow Tuff eruption (15 ka). In this last caldera-forming event, the inner and medial fault zones accommodated most of the collapse and were episodically reactivated during the younger volcano-tectonic activity. The second fault system occurs in the apical zone of the resurgent dome and comprises dominantly high-angle normal faults that are mainly related to the volcanotectonic collapse that followed the Agnano-Monte Spina Plinian eruption (4.55 ka). Finally, we provide a volcano-tectonic evolutionary model of the last 40 kyr, considering the interplay among ring and dome faults activity, volcaniclastic sedimentation, ground deformation and sea-level changes.

Description: Published

Description: 104723

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: Argnani (2021, hereinafter ARG2021) commented on the paper by Barreca et al. (2021, hereinafter BRC2021) titled: “The Strait of Messina: Seismotectonics and the source of the 1908 earthquake”, in which a new seismotectonic model and constraints on the possible source fault (the so-called W-Fault) for the 1908 disastrous seismic event were provided. Results from BRC2021 led to a revision of most of the previously published papers on the issue. ARG2021 commented both on the recent activity of the W-Fault and even about its existence in the offshore. In fact, according to the author's inferences: “it may belong to a fault system that is no longer active” and, contradictorily, “the offshore occurrence of the W-Fault is not supported by the data”. The comment is mostly based on a new tectonic interpretation that the author performed directly on the BRC2021 figures, where the offshore portion of the W-fault is illustrated. In this reply, we demonstrate that the interpretation provided by ARG2021 is affected by several oversights that led the author to erroneous conclusions about the issue. Accordingly, we strongly confirm both the occurrence of the W-Fault in the offshore and the present-day activity of this structure, the only active fault capable of producing large earthquakes in the Strait of Messina area.

Description: Published

Description: 103962

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: The sustainable management of water resources is required to avoid water scarcity becoming widespread. This article explores the potential application of a social-ecological framework, used predominantly in the fields of ecology and conservation, as a tool to improve the sustainability and resilience of water resources. The "red-loop green-loop" (RL-GL) model has previously been used to map both sustainable and unsustainable social-ecological feedbacks between ecosystems and their communities in countries such as Sweden and Jamaica. In this article, we demonstrate the novel application of the RL-GL framework to water resources management using the 2017/18 Cape Town water crisis. We used the framework to analyse the social-ecological dynamics of pre-crisis and planned contingency scenarios. We found that the water resources management system was almost solely reliant on a single, non-ecosystem form of infrastructure, the provincial dam system. As prolonged drought impacted this key water resource, resilience to resource collapse was shown to be low and a missing feedback between the water resource and the Cape Town community was highlighted. The collapse of water resources ("Day Zero") was averted through a combination of government and community group led measures, incorporating both local ecosystem (green-loop) and non-local ecosystem (red-loop) forms of water resource management, and increased rainfall returning to the area. Additional disaster management plans proposed by the municipality included the tighter integration of red and green-loop water management approaches, which acted to foster a stronger connection between the Cape Town community and their water resources. We advocate the wider development and application of the RL-GL model, theoretically and empirically, to investigate missing feedbacks between water resources and their communities.

Description: Despite an increasing understanding of the issue of marine pollution, humanity continues on a largely unsustainable trajectory. This study aimed to identify and classify the range of scientific studies and interventions to address coastal and marine pollution. We reviewed 2417 scientific papers published between 2000 and 2018, 741 of which we analysed in depth. To classify pollution interventions, we applied the systems-oriented concept of leverage points, which focuses on places to intervene in complex systems to bring about systemic change. We found that pollution is largely studied as a technical problem and fewer studies engage with pollution as a systemic social-ecological issue. While recognising the importance of technical solutions, we highlight the need to focus on under-researched areas pertaining to the deeper drivers of pollution (e.g. institutions, values) which are needed to fundamentally alter system trajectories.

Description: The productive but highly exposed coastline of the southern Benguela eastern boundary upwelling system offers limited natural environment for aquaculture. Saldanha Bay located on the west coast of South Africa is one of the few embayments on the coastline that provides a productive and relatively sheltered environment suitable for the cultivation of shellfish. Consequently, bivalve culture in South Africa is centered in Saldanha Bay and is presently targeted for expansion. Pseudo-nitzschia blooms including toxin-producing species are shown to contribute significantly to the phytoplankton of Saldanha Bay specifically in spring and summer. Their dominance at this time of the year, when upwelling is strongest, fits the ecological profile of Pseudo-nitzschia occurring during periods of high turbulence and nutrients. Multiple Pseudo-nitzschia blooms were sampled under varying environmental conditions and the strength of the relationship between Pseudo-nitzschia cell abundance and particulate domoic acid (pDA) content, reflecting bloom toxicity, varied greatly. This variability is the result of the combined influence of species and strain composition of the Pseudo-nitzschia assemblage and the effect of environmental conditions on toxin production. Elevated levels of pDA were associated with higher concentrations of cells of the P. seriata complex differentiated by frustule width (〉3 µm). P. australis was identified as a toxin-producing species and a prominent member of the P. seriata complex. Low DA levels in shellfish in Saldanha Bay are considered a function of low cellular domoic acid (cDA). Silicate limitation has emerged as an important factor inducing DA production in Pseudo-nitzschia species. The high ratio of silicate to nitrate in Saldanha Bay provides a plausible explanation for the low toxin content of Pseudo-nitzschia blooms in the bay and the consequent low risk posed by these blooms to the aquaculture sector.

Description: Goniodomin A (GDA, 1) is a phycotoxin produced by at least four species of Alexandrium dinoflagellates that are found globally in brackish estuaries and lagoons. It is a linear polyketide with six oxygen heterocyclic rings that is cyclized into a macrocyclic structure via lactone formation. Two of the oxygen heterocycles in 1 comprise a spiro-bis-pyran, whereas goniodomin B (GDB) contains a 2,7-dioxabicyclo[3.3.1]nonane ring system fused to a pyran. When H2O is present, 1 undergoes facile conversion to isomer GDB and to an α,β-unsaturated ketone, goniodomin C (GDC, 7). GDB and GDC can be formed from GDA by cleavage of the spiro-bis-pyran ring system. GDA, but not GDB or GDC, forms a crown ether-type complex with K+. Equilibration of GDA with GDB and GDC is observed in the presence of H+ and of Na+, but the equilibrated mixtures revert to GDA upon addition of K+. Structural differences have been found between the K+ and Na+ complexes. The association of GDA with K+ is strong, while that with Na+ is weak. The K+ complex has a compact, well-defined structure, whereas Na+ complexes are an ill-defined mixture of species. Analyses of in vitro A. monilatum and A. hiranoi cultures indicate that only GDA is present in the cells; GDB and GDC appear to be postharvest transformation products.

Description: It is important to understand the historical precedents of current situations to be able to anticipate where the current global environmental and climatic change may lead. Geo-historical data provide information beyond the limitations of instrumental data. This study aims to reconstruct components of the palaeoclimatic and palaeoenvironmental history of the Beagle Channel (BC) during the Late Holocene by using Ameghinomya antiqua shells. We use fossil and modern shells in a comparative analysis through a multiproxy approach, i.e., shell morphometrics, shell growth, and stable oxygen isotope ratios. A holistic analysis of all the proxies indicates that higher productivity occurred around 3542 yr B.P. in the BC, evidenced by more significant growth, size, and longevity in fossil specimens. In addition, smaller ligaments, cardinal teeth, and the pallial sinus in fossil specimens indicate a low-energy environment typical of a marine archipelago. Lastly, palaeotemperatures are estimated to be warmer than today, although the intensity may be overestimated due to the freshwater inflow that would change the salinity of the BC waters. Further analysis in Late-Holocene shells is essential for a more detailed environmental reconstruction around the southern tip of South America.

Description: Harmful algal blooms (HAB) are recurrent phenomena in northern Europe along the coasts of the Baltic Sea, Kattegat-Skagerrak, eastern North Sea, Norwegian Sea and the Barents Sea. These HABs have caused occasional massive losses for the aquaculture industry and have chronically affected socioeconomic interests in several ways. This status review gives an overview of historical HAB events and summarises reports to the Harmful Algae Event Database from 1986 to the end of year 2019 and observations made in long term monitoring programmes of potentially harmful phytoplankton and of phycotoxins in bivalve shellfish. Major HAB taxa causing fish mortalities in the region include blooms of the prymnesiophyte Chrysochromulina leadbeateri in northern Norway in 1991 and 2019, resulting in huge economic losses for fish farmers. A bloom of the prymesiophyte Prymnesium polylepis (syn. Chrysochromulina polylepis) in the Kattegat-Skagerrak in 1988 was ecosystem disruptive. Blooms of the prymnesiophyte Phaeocystis spp. have caused accumulations of foam on beaches in the southwestern North Sea and Wadden Sea coasts and shellfish mortality has been linked to their occurrence. Mortality of shellfish linked to HAB events has been observed in estuarine waters associated with influx of water from the southern North Sea. The first bloom of the dictyochophyte genus Pseudochattonella was observed in 1998, and since then such blooms have been observed in high cell densities in spring causing fish mortalities some years. Dinoflagellates, primarily Dinophysis spp., intermittently yield concentrations of Diarrhetic Shellfish Toxins (DST) in blue mussels, Mytilus edulis, above regulatory limits along the coasts of Norway, Denmark and the Swedish west coast. On average, DST levels in shellfish have decreased along the Swedish and Norwegian Skagerrak coasts since approximately 2006, coinciding with a decrease in the cell abundance of D. acuta. Among dinoflagellates, Alexandrium species are the major source of Paralytic Shellfish Toxins (PST) in the region. PST concentrations above regulatory levels were rare in the Skagerrak-Kattegat during the three decadal review period, but frequent and often abundant findings of Alexandrium resting cysts in surface sediments indicate a high potential risk for blooms. PST levels often above regulatory limits along the west coast of Norway are associated with A. catenella (ribotype Group 1) as the main toxin producer. Other Alexandrium species, such as A. ostenfeldii and A. minutum, are capable of producing PST among some populations but are usually not associated with PSP events in the region. The cell abundance of A. pseudogonyaulax, a producer of the ichthyotoxin goniodomin (GD),has increased in the Skagerrak-Kattegat since 2010, and may constitute an emerging threat. The dinoflagellate Azadinium spp. have been unequivocally linked to the presence of azaspiracid toxins (AZT) responsible for Azaspiracid Shellfish Poisoning (AZP) in northern Europe. These toxins were detected in bivalve shellfish at concentrations above regulatory limits for the first time in Norway in blue mussels in 2005 and in Sweden in blue mussels and oysters (Ostrea edulis and Crassostrea gigas) in 2018. Certain members of the diatom genus Pseudonitzschia produce the neurotoxin domoic acid and analogs known as Amnesic Shellfish Toxins (AST). Blooms of Pseudo-nitzschia were common in the North Sea and the Skagerrak-Kattegat, but levels of AST in bivalve shellfish were rarely above regulatory limits during the review period. Summer cyanobacteria blooms in the Baltic Sea are a concern mainly for tourism by causing massive fouling of bathing water and beaches. Some of the cyanobacteria produce toxins, e.g. Nodularia spumigena producer of nodularin, which may be a human health problem and cause occasional dog mortalities. Coastal and shelf sea regions in northern Europe provide a key supply of seafood, socioeconomic well-being and ecosystem services. Increasing anthropogenic influence and climate change create environmental stressors causing shifts in the biogeography and intensity of HABs. Continued monitoring of HAB and phycotoxins and the operation of historical databases such as HAEDAT provide not only an ongoing status report but also provide a way to interpret causes and mechanisms of HABs.

Description: The IOC-ICES-PICES Harmful Algal Event Database (HAEDAT) was used to describe the diversity and spatiotemporal distribution of harmful algal events along the Atlantic margin of Europe from 1987 - 2018. The majority of events recorded are caused by Diarrhetic Shellfish Toxins (DSTs). These events are recorded annually over a wide geographic area from southern Spain to northern Scotland and Iceland, and are responsible for annual closures of many shellfish harvesting areas. The dominant causative dinoflagellates, members of the morphospecies ‘Dinophysis acuminata complex’ and D. acuta, are common in the waters of the majority of countries affected. There are regional differences in the causative species associated with PST events; the coasts of Spain and Portugal with the dinoflagellates Alexandrium minutum and Gymnodinium catenatum, north west France/south west England/south Ireland with A. minutum, and Scotland/Faroe Islands/Iceland with A. catenella. This can influence the duration and spatial scale of PST events as well as the toxicity of shellfish. The diatom Pseudo-nitzschia australis is the most widespread Domoic Acid (DA) producer, with records coming from Spain, Portugal, France, Ireland and the UK. Amnesic Shellfish Toxins (ASTs) have caused prolonged closures for the scallop fishing industry due to the slow depuration rate of DA. Amendments to EU shellfish hygiene regulations introduced between 2002 and 2005 facilitated end-product testing and sale of adductor muscle. This reduced the impact of ASTs on the scallop fishing industry and thus the number of recorded HAEDAT events. Azaspiracids (AZAs) are the most recent toxin group responsible for events to be characterised in the ICES area. Events associated with AZAs have a discrete distribution with the majority recorded along the west coast of Ireland. Ciguatera Poisoning (CP) has been an emerging issue in the Canary Islands and Madeira since 2004. The majority of aquaculture and wild fish mortality events are associated with blooms of the dinoflagellate Karenia mikimotoi and raphidophyte Heterosigma akashiwo. Such fish killing events occur infrequently yet can cause significant mortalities. Interannual variability was observed in the annual number of HAEDAT areas with events associated with individual shellfish toxin groups. HABs represent a continued risk for the aquaculture industry along the Atlantic margin of Europe and along the Atlantic margin of Europe and should be accounted for when considering expansion of the industry or operational shifts to offshore areas.

Description: Seismic Probabilistic Tsunami Hazard Assessment (SPTHA) is a framework for calculating the probability that seismically induced tsunami waves exceed a specific threshold height, over a given time span and a specific region (i.e. regional SPTHA) or site (i.e. local SPTHA). To account for the uncertainty of the possible sources, SPTHA must integrate the results of a large number of computationally demanding tsunami simulations In this work, we innovatively use Parallel density scanned Adaptive Kriging (P-ds AK) to overcome the computational efficiency challenge of local SPTHA within a framework that consists in modeling/retrieving the full spectrum of possible earthquake triggering events at the regional level, filtering sources not relevant for the target, adopting a clustering procedure to select “representative scenarios” for inundation modeling, and, finally, adopt P-ds AK to identify the clusters centroids that most influence the hazard intensity (i.e., wave height) in the areas of interest. This approach is applied in the area of the oil refinery located in Milazzo (Italy). The application shows a consistent reduction of the number of high-resolution tsunami simulations required for the evaluation of the hazard curves over a set of inland Point of Interest (PoIs), either concentrated in one specific area or distributed along the coast.

Description: Published

Description: 108441

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: The Colli Albani volcanic district emplaced huge pyroclastic-flow deposits up to 20 m thick in the southeastern suburbs of the City of Rome. The soil quality onto the gentle slopes of the Colli Albani has certainly contribute to the growth of Ancient Rome, a city with one million inhabitants as early as 2000 years ago. Interestingly, the Colli Albani soils developed on K-foiditic pyroclastic rocks with peculiar low silica, high alkali and high CaO composition. In the past, the productivity of the Colli Albani soils was maximized without the understanding of the unique physical, chemical, and mineralogical properties of these soils; now an in-depth knowledge of the Colli Albani soils is necessary to respond to the current and increasingly demand of sustainable soil use.

Description: Published

Description: 105430

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: Through the analysis of seven 15 to 30 m deep boreholes drilled in the western sector of the Circus Maximus we reconstruct the aggradational history of one main tributary valley of the Tiber River in Rome, the Murcia Valley ( Vallis Murcia) .

Description: Published

Description: 44-53

Description: 5A. Ricerche polari e paleoclima

Description: JCR Journal

Description: The Acheulian and early Middle Paleolithic assemblages from Torre in Pietra (Latium, Italy) were never securely dated before. We have now 49 Ar/39Ar dates and ESR-U-series dates which support corrrelations to marine isotope stages. The Acheulian (previously correlated to MIS 9) is now dated to MIS 10 while the Middle Paleolithic is dated to MIS 7. The analysis and comparisons of the two assemblages and comparisons with the Acheulian small tools of Castel di Guido show a culturally transmitted pattern of technology that was shared by the craftsmen of the region.

Description: Published

Description: 1-11

Description: 5A. Ricerche polari e paleoclima

Description: JCR Journal

Description: With the aim of deepening our understanding of deep-seated fluids upwelling and mixing in large regional aquifers, we performed a hydrogeochemical study of twenty-two springs in the Contursi area (upper Sele river valley, southern Apennines) by means of the measurements of chemical-physical parameters, major ions, trace elements, and stable and radioactive isotopes. Besides, we realized two updated geo-structural cross-sections inorder to reconstruct the groundwater flowpath in the study area. The hydrogeochemical composition, as well a the water temperature allow to identify-three main groups of groundwater: Cold and Low salinity Groundwater (CLGW), Intermediate Salinity Groundwater (ISGW), and Thermal Salinity Groundwater (TSGW). The CLGW group, mostly emerging at the boundary of carbonate aquifers, is characterized by alkaline earth-bicarbonate hydrofacies. Instead, ISGW and TSGW, situated in the inner zone of the valley, show gradually a hydrogeochemical evolution towards sodium-chloride type hydrofacies domain with the highest salinity value. Stable isotope (δ18O-δD) of CLGW reveal the local meteoric origin of groundwater, while isotopic signatures of ISGW and TSGW is associated with the deep fluids inflow. CLGW hydrogeochemistry is clearly related to dissolution of carbonate rocks. On the other hand, for ISGW and TSGW an additional contribution from evaporitic rocks is supported by saturation indices values (gypsum and anhydrite) and validated by isotopic signature of dissolved sulphate (δ34S-δ18O). The application of two models based on tritium data (i.e., the piston-flow and well-mixed reservoir) attributes longer and deeper groundwater flowpaths to TSGW. Through geothermometric calculations (e,g., K-Mg and SiO2-quartz), the equilibrium temperature of deep fluids reservoir is also extrapolated (i.e., 75–96 ◦C). The results of the adopted hydrogeochemical multi-component approach allowed us to propose an interpretative model of groundwater flowpath for the Contursi area, where deep-seated tectonic discontinuities play a significant role for the upwelling of saline deep thermal fluids in shallow aquifers.

Description: Published

Description: 129258

Description: 9T. Geochimica dei fluidi applicata allo studio e al monitoraggio di aree sismiche

Description: JCR Journal

Description: We propose a procedure based on remote sensing Sentinel-1 InSAR data aiming at evaluating the variability of the moment tensor solutions provided by different agencies in case of light-to-moderate earthquake. We model the expected coseismic ground deformations from the available moment tensor solutions and compare them with the real ones retrieved with the InSAR data. Any differences between location and intensity of simulated and estimated seismic-induced deformation fields allow indirectly evaluating the variability of the solutions in terms of epicenter locations and kinematics of the causative faults. We applied this investigation method to several light (4〈Mw 〈 4.9) to moderate (5〈Mw 〈 5.9) earthquakes occurred along the Mediterranean area since the launch of the Sentinel-1A mission in 2014. The selected seismic events cover all the faulting mechanisms and are characterized by different estimated magnitudes and depths thus offering a synoptic view of the performance of the procedure in several cases. Thanks to the global coverage and the unprecedented revisit time of Sentinel-1 acquisitions, the proposed procedure can be easily extended to any seismic event occurred inland worldwide.

Description: Published

Description: 100057

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: 42 pages

Description: In this study, we propose an analysis of the earthquake clusters that occurred in North-Eastern Italy and western Slovenia from 1977 to today. Given a mainshock generating alarm in the population, we are interested in forecasting if a similar magnitude earthquake will follow. We classify the earthquake clusters associated with mainshocks of magnitude Mm into two classes: if the strongest aftershock has a magnitude 〉=Mm-1 (swarms or large aftershock seismic sequences) as type A, otherwise (smaller aftershocks seismic sequences) as type B. A large aftershock following a main shock can cause significant damages to already weakened buildings and infrastructures, so a timely advisory information to the civil protection is of great interest for effective decision-making. For the first time, we applied to a new catalogue a pattern recognition algorithm for cluster type forecasting that we developed for all Italy (Gentili and Di Giovambattista, 2017). Thanks to the lower completeness magnitude of the local OGS catalogue, compared to the national one, and to a new version of the algorithm, we were able to lower the threshold of the clusters mainshocks magnitude from 4.5 to 3.7. The method has been validated by rigorous statistical tests. We tested the algorithm on the 1976 highly destructive earthquake cluster (mainshock magnitude 6.5 - the strongest in the last 80 years in the region) and we retrospectively forecasted it as an A cluster. Successful results were obtained also on other three smaller earthquake clusters in 2019.

Description: Published

Description: 106483

Description: 4T. Sismicità dell'Italia

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: The knowledge of the secular variation of the geomagnetic field at different time scales is important to determine the mechanisms that maintain the geomagnetic field and can help to establish constraints in dynamo theories. We have focused our study on the secular variation at millennial and centennial time scale searching for characteristic periods during the last 10 kyr. The frequency study was performed using four recent updated global paleomagnetic field reconstructions (SHA.DIF.14k, CALS10k.2, BIGMUDI4k and SHAWQ2k) by applying three techniques commonly used in signal analysis: the Fourier transform, the Empirical Mode Decomposition, and the wavelet analysis. Short-term variability of the geomagnetic field energy shows recurrent periods of around 2000, 1000–1400, and 600–800 and 250–400 years. The characteristic time around 600–800 years is well determined in all paleomagnetic reconstructions and it is mostly related to the axial dipole and axial octupole terms, but also observable in the equatorial dipole. In addition to this period, longer characteristic times of around 1000–1400 years are found particularly in the equatorial dipole and quadrupole terms in SHA.DIF.14k, CALS10k.2 and BIGMUDI4k while the 2000 year period is only well determined in the total geomagnetic field energy of SHA.DIF.14k and CALS10k.2. The most detailed paleoreconstructions for younger times also detect shortest characteristic times of around 250–400 years. The long-term variation of the geomagnetic energy is only observable in the axial dipole. A characteristic period of around 7000 years in both SHA.DIF.14k and CALS10k.2 has been found. This long period is related to two decays in the dipole field and a period of increasing intensity. The oldest decay took place between 7000 BCE and 4500 BCE and the present decay that started around 100 BCE. We have modeled the 4500 BCE up to present variation as a combination of a continuous decay, representing the diffusion term of the geomagnetic field, and one pulse that reinforces the strength of the field. Results show a characteristic diffusion time of around 11,000–15,000 years, which is compatible with the diffusion times of the dipole field used in geodynamo theories.

Description: Published

Description: 106656

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: JCR Journal

Description: Ship traffic, population, infrastructure development, and mining activities are expected to increase in the Arctic due to its rising temperatures. This is expected to produce a major impact on aerosol composition. Metals contained in atmospheric particles are powerful markers and can be extremely helpful to gain insights on the different aerosol sources. Thiswork aims at studying the sources of metals in the Arctic aerosol sampled at the Thule High Arctic Atmospheric Observatory (THAAO; Greenland, 76.5°N 68.8°W). Due to the particular composition of Greenlandic soils and to properties of other sources, it was possible to find several signatures of natural and anthropogenic aerosols transported from local and long-range regions. Arctic haze (AH) at Thule builds up on long-range transported aerosol mainly from Canada and Nord America. From a chemical standpoint, this aerosol is characterized by a high concentration of sulfate, Pb, As and Cd and by a La/Ce ratio larger than 1. The Ti/Al and Fe/Al ratios in the AH aerosol are lower (Ti/Al = 0.04 w/w; Fe/ Al= 0.79 w/w) than for local aerosol (Ti/Al= 0.07 w/w; Fe/Al = 0.89 w/w). Conversely, aerosol arising from coastal areas of South-West Greenland is characterized by a high concentration of V,Ni, and Cr. These metals, generally considered anthropogenic, arise heremainly fromnatural crustal sources. In some summer samples, however, the V/Ni ratio becomes larger than 3. In particular, cases displaying this characteristic ratio, as also shown by backward trajectories, are associated with sporadic transport to Thule of ship aerosol from ships passing through Baffin Bay and arriving to Thule during summer. Although further measurements are necessary to confirm the discussed results, the analysis carried out in this work on a large number of metals sampled in coastal Greenland aerosol is unprecedented.

Description: Published

Description: 140511

Description: 5A. Ricerche polari e paleoclima

Description: JCR Journal

Description: Calc-alkaline and alkaline magmatic activity is generally separated in space and/or in time. The Eastern Transylvanian Basin in Romania is one of the few places where, during Pleistocene, alkaline eruptions occurred contemporaneously with the calc-alkaline activity. Mantle xenoliths entrained in Perşani Mts. alkaline volcanic products have been studied in order to investigate the interaction of metasomatic agents of different magmatic affinities with the mantle wedge. Based on mineral major and trace element and noble gases in fluid inclusions, two main events have been recognized. The first was a pervasive, complete re-fertilization of a previously depleted mantle by a calc-alkaline subduction-related melt, causing the formation of very fertile, amphibole-bearing lithotypes. This is shown by the a) increased amounts of modal clinopyroxene up to 21.9 % with Al2O3 contents up to 8.16 wt%, higher than what is expected for clinopyroxene in Primordial Mantle; b) 4He/40Ar* ratios up to 1.2, within the reported range for mantle production; c) 3He/4He in olivine, opx and cpx of 5.8 ± 0.2 Ra, among the most radiogenic values of European mantle, below the typical MORB mantle value (8 ± 1 Ra), reflecting recycling of crustal material in the local lithosphere. The second event is related to later interaction with an alkaline metasomatic agent similar to the host basalts that caused slight LREE enrichment in pyroxenes and disseminated amphiboles and precipitation of vein amphiboles with a composition similar to amphiboles megacrysts also found in the Perşani Mts. volcanic deposits. This is highlighted by the 4He/40Ar* and 3He/4He values found in some opx and cpx, up to 2.5 and 6.6 Ra, respectively, more typical of magmatic fluids.

Description: Published

Description: 105516

Description: 1T. Struttura della Terra

Description: 1V. Storia eruttiva

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: JCR Journal

Description: The Larderello-Travale Geothermal Field in South-West Tuscany (Italy) is the oldest and among the most pro- ductive geothermal fields in the world. A new 3D model of seismic P-wave velocity (V P ) of the upper crust beneath the geothermal field is derived by inverting a set of highly consistent travel-times from local-earth- quakes. Results document a marked correlation of V P with previously described, high-reflectivity horizons. We also determined a low velocity body (V P ∼5 km s −1 ) culminating at depths of about 7 km, with estimated vo- lume of 35–40 km 3 . Such low velocities are consistent with a granite at temperatures above 700 °C, thus in a partially-molten status.

Description: Published

Description: 101731

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: Boron (B) and Lithium (Li) concentrations were studied in the Platani river, one of the most important catchments of South-Central Sicily which is under semiarid climatic conditions for roughly eight months to a year. In this area, evaporites result in potential B and Li sources for surface waters. Results from river waters have measured ionic strength values between 0.1 and 4.54 M. B and Li distributions in these waters were studied in colloidal (CF, extracted by ultrafiltration from the 0.45 μm filtrate) and total dissolved (TDF) fractions and in fractions extracted from corresponding riverbed sediments, according to changes of the B/Li ratio. In river waters, CF and TDF showed very similar B/Li values, suggesting that only negligible fractionation occurs between Li and B in the aqueous phase. Similar evidence was observed between B/Li values in TDF and the labile sediment fraction, whereas an inverse relationship arose between B/Li values in TDF and in the easily reducible sediment fraction. This relationship indicates that Mn oxy-hydroxides preferentially react with aqueous B species relative to Li at the riverbed sediment interface. The extent of the B-Mn oxy-hydroxide reactions is influenced by the ionic strength, so that only B/Li values below 4 are measured in river waters with ionic strength values above 0.5 M. Comparing B/Li and ionic strength values measured in the Platani river with those from oxic brines worldwide, the same preferential B removal relative to Li is observed. This evidence suggests that B is removed as positively-charged borate ion-pairs, formed in the aqueous phase under higher ionic strength conditions, reacting with negatively charged surfaces of Mn oxy-hydroxides. The observed B reactivity relative to Li could be exploited to bring down the B excess from natural or waste waters, allowing the natural reactions with Mn oxy-hydroxides to take place under natural conditions.

Description: Published

Description: 135509

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: Numerous sand boils were generated in the alluvial plain at the mouth of the Rio Brice˜no valley (Ecuador) during the Mw 7.8 earthquake of April 2016. The area is characterized by a series of raised marine terraces formed as a consequence of the rapid tectonic coastal uplift during the Quaternary. Boreholes and geotechnical investigations were carried during post-earthquake surveys and for the purpose of mitigating the liquefaction effects. Five lithological units were identified at a site of embankment, which represented continental-marine and transitional sedimentation since the Last Glacial Maximum. A comprehensive study of texture and petrographic composition of sand boils has been performed and compared with sandy silts and silty sands of the buried sedimentary sequence in order to identify the source levels for liquefaction. The petrographic components, in particular the low content of bioclasts and carbonate fragments of the sand boils, allow to pinpoint a source layer made up of fine-grained silty sands located between 2 and 4.5 m depth (Unit 2) whereas the deeper marine sands, richer in bioclasts, were not involved. The results support the idea that earthquake-induced liquefaction phenomena are not restricted to clean sands and well-sorted deposits, but may affect sand layers with significant amount of nonplastic silt.

Description: Published

Description: 102737

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: Although explosivity is linked with high decompression rates induced by magma ascent, the quantitative relationships between decompression rate and eruption energy have yet to be properly assessed, especially for open-conduit basaltic volcanoes, where ordinary weak activity can rapidly evolve into more intense eruptions. Here, we selected three eruptions of different explosivity from Mt. Etna’s recent activity to study the relationships between the observed explosive intensities and decompression rates determined through diffusion chronometry, which is based on modeling volatile diffusion along olivine-hosted melt embayments. The approach used in this study has provided important indications on differences in the timescales of decompression-driven degassing for magmas emitted with markedly distinct eruptive dynamics, starting from similar physical and chemical conditions of the magmas involved in the three eruptions. The intense paroxysmal activity at Voragine Crater on December 3, 2015, was fostered by high decompression rate (∼0.36-0.74 MPa/s), slightly higher than in the less energetic paroxysm that occurred on February 19, 2013, at New South-East Crater (NSEC) (∼0.14-0.29 MPa/s). Decompression rates of magmas emitted during lava fountaining are one order of magnitude greater than values obtained for the mild flank eruption that occurred in December 2018 (∼0.045-0.094 MPa/s). Our results indicate that degassing kinetics controlled the intensity of activity at Mt. Etna, thus suggesting that the explosivity does not depend exclusively on the degree of overpressurization of the shallowest reservoir due to injection of gas from the deepest levels of the plumbing system.

Description: Published

Description: 117821

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: •Anthropogenic CO2 flux can be estimated by stable isotopic surveying. •Gas emissions from human activities force the atmospheric CO2. •The monitoring of stable isotopes allows identifying the CO2 sources in the air. •Several tons per day of CO2 flow through the geosphere in urban zones. •Transient in the air CO2 occurs owing to changes in weather variables.

Description: Atmospheric carbon dioxide (CO2) concentrations increase due to volcanic emissions, diffuse degassing from fault zones, and various human-caused gas emissions, especially in densely populated urban zones, which play a pivotal role in the ongoing climate change. This study aims to examine changes in the concentration and stable isotopic composition of atmospheric CO2. A laser-based analyzer provided the δ13C and δ18O values based on concentration measurements for various CO2 isotopologues. Multiple linear regression (MLR) showed that almost 30% of the atmospheric CO2 changes are caused by weather variations, while ~70% of the changes involve CO2 from various gas sources related to human activities. The Keeling plot approach was used to identify the isotopic signature of the extra CO2, which points to the gas produced by hydrocarbon combustion. An isotopic mass balance model was designed to show the relation between excess atmospheric CO2 and the flux of human-related gas emissions. Calculating the CO2 flux in the atmosphere based on this isotopic mass balance model showed that several tons of CO2 move daily between geospheres. This study shows that surveying atmospheric CO2 in urban zones allows quantifying the CO2 emissions from various sources.

Description: Published

Description: 119302

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: 1TR. Georisorse

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: 2IT. Laboratori analitici e sperimentali

Description: 6IT. Osservatori non satellitari

Description: JCR Journal

Description: The Present-day (〈1.2 kyr) activity of Stromboli (Aeolian Islands, Southern Italy) is fed by a vertically-extended mush column with an open-conduit configuration. The eruptive products are the result of periodic supply of mafic magma (low porphyritic or Lp-magma) from depth into a homogeneous shallow reservoir (highly porphyritic or Hp-magma). Clinopyroxene phenocrysts from the 2003–2017 activity exhibit marked diopside-augite heterogeneities caused by continuous Lp-Hp magma mixing and antecryst recycling. Diopsidic bands record Lp-recharge injected into the shallow Hp-reservoir, whereas resorbed diopsidic cores testify to the continuous disruption and cannibalism of relic antecrysts from the mush. The transition between diopside (∼1175 °C) and augite (∼1130 °C) takes place at comparable P (∼190 MPa) and H2O (0.5–2.4 wt%) conditions. Short timescales (∼1 year) for diopsidic bands from the 2003 paroxysm document restricted temporal intervals between mafic injection, magma mixing and homogenization in the Hp-reservoir. Longer timescales (∼4–182 years) for diopsidic cores indicate protracted antecryst remobilization times. By comparing clinopyroxenes from the Present-day and Post-Pizzo eruptions, we argue a distinct phase in the life of Stromboli volcano is evident from the 2003 paroxysm onwards. More efficient mechanisms of mush disruption and cannibalism involve diopsidic antecrysts remobilized and transported by Lp-magmas permeating the mush, in concert with gravitational instability of the solidification front and melt migration within the shallow Hp-reservoir. Magmatic injections feeding the persistent Present-day activity are more intensively mixed and homogenized prior to eruption, reflecting small recharge volumes and/or a more mafic system in which the mafic inputs are less pronounced.

Description: Published

Description: 105440

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: In Antarctica, the near-source exposures of volcanic eruption deposits are often limited as they are not well preserved in the dynamic glacial environment, thus making volcanological reconstructions of explosive eruptions extremely challenging. Fortunately, pyroclastic deposits from explosive eruptions are preserved in Southern Ocean sediments surrounding Antarctica, and the tephrostratigraphy of these sequences offers crucial volcanological information including the timing and tempo of past eruptions, their magnitude, and eruption dynamics. Here we report the results of a tephrostratigraphy and tephrochronology study focused on four sediment cores recovered from the Wood Bay area in the western Ross Sea, Antarctica. In all these sedimentary sequences, we found a well-stratified primary tephra of considerable thickness, up to 80 cm, hereafter named the Aviator Tephra (AVT). According to the characteristics of the tephra deposit and its distribution, the AVT was associated with an eruption of considerable intensity, potentially representing one of the largest Holocene eruptions recorded in Antarctica. Based on the major and trace element geochemistry and the mineral assemblage of the tephra, Mount Rittmann was identified as the source of the AVT. A Holocene age of ∼11 ka was determined by radiocarbon dating organic material within the sediments and 40Ar-39Ar dating of alkali-feldspar crystals included in the tephra. Eruption dynamics were initially dominated by hydromagmatic magma fragmentation conditions producing a sustained, relatively wet and ash-rich eruptive cloud. The eruption then evolved into a highly energetic, relatively dry magmatic Plinian eruption. The last phase was characterized by renewed efficient magma-water interaction and/or collapse of the eruptive column producing pyroclastic density currents and associated co-ignimbritic plumes. The distal tephra deposits might be linked to the widespread lag breccia layer previously identified on the rim of the Mount Rittmann caldera which share the same geochemical composition. Diatoms found in the sediments surrounding the AVT and the primary characteristics of the tephra indicate that the Wood Bay area was open sea at the time of the eruption, which is much earlier than previously thought. AVT is also an excellent tephrostratigraphic marker for the Wood Bay area, in the Ross Sea, and a useful marker for future synchronization of continental ice and marine archives in the region.

Description: Published

Description: 106629

Description: 1V. Storia eruttiva

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: 5A. Ricerche polari e paleoclima

Description: JCR Journal

Description: In active volcanic zones, fault dynamics is considerably fast but it is often difficult to separate the pattern of nearly continuous large-scale volcanic processes (inflation/deflation processes, flank instability) from impulsive episodes such as dyke intrusions or coseismic fault displacements. At Etna, multidisciplinary studies on active faults whose activity does not strictly depend on volcanic processes, are relatively few. Here we present the case-study of the San Leonardello fault, an active structure located in the eastern flank of Mt. Etna characterised by a well-known seismic history. This fault saw renewed activity in May 2009, when pre-seismic creeping along the southern segment preceded an MW 4.0 earthquake in the northern segment, followed by some twenty-five aftershocks. Later, in March–April 2016, creep events reactivated the southern section of the same fault. Both the seismic and aseismic phenomena were recorded by the seismic and GNSS networks of INGV-Osservatorio Etneo, and produced surface faulting that left a footprint in the pattern of ground deformation detected by the InSAR measurements. We demonstrate that the integration of multidisciplinary data collected for volcano surveillance may shed light on different aspects of fault dynamics, and allow understanding how coseismic slip and creep alternate in space and time along the strike. Moreover, we use findings from our independent datasets to propose a conceptual model of the San Leonardello fault, taking into account behaviour and previous constraints from fault-based seismic hazard analyses. Although the faulting mechanisms described here occur at a very small scale compared with those of a purely tectonic setting, this case-study may represent a perfect natural lab for improving knowledge of seismogenic processes, also in other fault zones characterised by stick slip vs. stablesliding fault behaviour.

Description: Published

Description: 228554

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: Over the last decade machine learning has become increasingly popular for the analysis and characterization of volcano-seismic data. One of the requirements for the application of machine learning methods to the problem of classifying seismic time series is the availability of a training dataset; that is a suite of reference signals, with known classification used for initial validation of the machine outcome. Here, we present PICOSS (Python Interface for the Classification of Seismic Signals), a modular data-curator platform for volcano-seismic data analysis, including detection, segmentation and classification. PICOSS has exportability and standardization at its core; users can select automatic or manual workflows to select and label seismic data from a comprehensive suite of tools, including deep neural networks. The modular implementation of PICOSS includes a portable and intuitive graphical user interface to facilitate essential data labelling tasks for large-scale volcano seismic studies.

Description: Published

Description: 104531

Description: 8T. Sismologia in tempo reale

Description: JCR Journal

Description: In volcanic areas, accurate localization of earthquakes requires detailed velocity and, possibly, attenuation models, taking into account wide lithological variability and high geothermal gradients. Ischia island (Campania region, Italy) is a seismically-active volcano recently affected by a Mw 3.9 event (Casamicciola, August 21, 2017, 1 km depth). Due to the lack of a specific velocity model, the earthquakes occurred on the island were localized using the one developed for the nearby Campi Flegrei caldera. The aim of this work is the definition of a mean representative 1D shear-wave velocity (Vs) and attenuation (Q) model of the shallower crust (up to 2 km depth) of Ischia. Seismic noise array and spectral ratios techniques were applied to broad band seismic signals recorded by temporary and permanent networks updated after the August 2017 earthquake. The values of both shear-wave velocity (Vs) and quality factor (Q) are realistic, with Q values comparable with those obtained for Campi Flegrei and Stromboli volcanic areas. By taking into account stratigraphic information from deep wells and ultrasonic measurements of velocity on granite and trachytic lava samples, a geological interpretation of the resulting velocity model is provided. Such a model can have significant implications for understanding the dynamics of a volcano, mainly those leading to seismic activity.

Description: Published

Description: 106970

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: Numerous studies exist on exhumed tectonic mélanges along subduction channels whereas, in accretionary wedge interiors, deformation mechanisms and related fluid circulation in tectonic mélanges are still underexplored. We combine structural and microstructural observations with geochemical (stable and clumped isotopes and isotope composition of noble gases in fluid inclusions of calcite veins) and U-Pb geochronological data to define deformation mechanisms and syn-tectonic fluid circulation within the Mt. Massico intra-wedge tectonic mélange, located in the inner part of the central-southern Apennines accretionary wedge, Italy. This mélange developed by shear deformation at the base of a clastic succession. Deformation was characterized by disruption of the primary bedding, mixing, and deformation of relicts of competent olistoliths and strata within a weak matrix of deformed clayey and marly interbeds. Recurrent cycles of mutually overprinting fracturing/veining and pressure-solution processes generated a block-in-matrix texture. The geochemical signatures of syntectonic calcite veins suggest calcite precipitation in a closed system from warm (108°-147 °C) paleofluids, with δ18O vlaues between þ9‰ and 14‰, such as trapped pore waters after extensive 18O exchange with the local limestone host rock and/or derived by clay dehydration processes at T 〉 120 °C. The 3He/4He ratios in fluid inclusions are lower than 0.1 Ra, indicating that He was exclusively sourced from the crust. We conclude that: (1) intraformational rheological contrasts, inherited trapped fluids, and low-permeability barriers such as marlyshaly matrix, can promote the generation of intra-wedge tectonic mélanges and the development of transient fluid overpressure; (2) clay-rich tectonic mélanges, developed along intra-wedge décollement layers, may generate low-permeability barriers hindering the fluid redistribution within accretionary wedges.

Description: Published

Description: 104086

Description: 1T. Struttura della Terra

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: In this paper, we study the spatial distribution and temporal evolution of the postseismic deformation of the 2010–2011 Rigan earthquake sequence which occurred at the southern termination of the East Lut fault system, southeast Iran. One-year GPS measurements after the Rigan earthquake sequence reveals right-lateral postseismic displacement along the East Chahqanbar fault and left-lateral postseismic displacement along the South Chahqanbar fault. To investigate the deformation variations in time and space, InSAR time-series of COSMO-SkyMed images is applied using the Small Baseline Subset algorithm. The results confirm a clear cumulative postseismic signal increasing to 8 mm during the first five months following the first mainshock in the direction of the coseismic displacement. The cumulative postseismic displacements are well correlated with the cumulative number of the aftershocks and their associated moment release. Considering this correlation and the observation of a sharp discontinuity along the coseismic fault in the displacement map, it is concluded that the after-slip mechanism is responsible for the observed postseismic deformation in the study region. This study is the first observation of a short-term postseismic motion in eastern Iran through geodetic data in contrast with long-lasting postseismic displacements following the earthquakes that occurred around Lut block. Modeling of the postseismic displacement results in a distributed slip pattern with a maximum slip of 0.8 m on the fault plane responsible for the 2010 Rigan coseismic deformation. This indicates that the postseismic deformation on barriers remained unbroken during the mainshock.

Description: Published

Description: 228630

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: The MEV project is running for a long-term muography measurement at the North-East crater of the Etna Volcano, after the successful conclusion of the test phase in July 2017. Two sets of data were already acquired during 2017, during the last months of the summer, and 2018. Data analysis is currently ongoing in order to extract a two-dimensional density map of the target from the measured muon flux. But before, a major improvement on data pre-processing was required. It regards in particular the algorithm for event reconstruction and filtering and the introduction of a method to extract the telescope efficiency from data themselves. The main steps of this pre-analysis and their application to the test data set is described in this paper.

Description: Published

Description: 162052

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: Preliminary interpretation of geological processes during field measurement campaigns require fast data analysis to adapt ongoing target strategies. It is the case of soil investigations where coupling geochemical and geophysical records favors a better understanding of subsurface processes. This task requires (i) statistical analysis to identify areas of interest during spatial surveys and (ii) signal processing to analyze temporal series. Here we present SoilExp, an open-source Python-based Graphical User Interface (GUI) that permits to process spatial and temporal surveys of soil gases (e.g. soil CO2 flux) combined with common physical parameters (e.g. self-potential, temperature) that are synchronously recorded on the field. SoilExp mixes innovative algorithms with the more common tools used for the analysis of both spatial surveys or temporal series. It offers the possibility to display distribution plots, maps, comparative plots, spectra and spectrograms, as well as data statistical analysis, in order to deal efficiently with datasets acquired on the field. Field measurements performed at Stromboli (Italy) supports that such software solution facilitates a quick visualization of the data output and is a powerful tool on the geochemical and geophysical analysis.

Description: Published

Description: 104553

Description: 4V. Processi pre-eruttivi

Description: 5V. Processi eruttivi e post-eruttivi

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: The anthropogenic impact of conventional energy sources encourages the utilization of revenable energy, as it has become a strategic commodity for economic growth. On the other hand, institutional stability is the prerequisite...

Description: Published

Description: 100484

Description: 7SR AMBIENTE – Servizi e ricerca per la società

Description: JCR Journal

Description: Ocean environmental conditions can be inferred from the chemical composition of bamboo coral skeletons. The high magnesium calcite internodes of these long-living octocorals may therefore represent a potential archive for seawater properties such as salinity or temperature where instrumental time series are absent. To extend these time series into the past using a natural archive the principles of temperature and salinity signal incorporation into cold-water coral skeletal material need to be investigated. Since skeletal Na and S concentrations have been proposed as environmental proxies, we mapped the spatial distribution and concentration of these elements in two Atlantic specimens of Keratoisis grayi (family Isididae). These measurements were conducted with an electron microprobe applying a spatial resolution of 4 μm. The mean apparent distribution coefficient of Na/Ca for the two samples was within 2.5 and 2.8*10−4, while that of S shows a similar depletion relative to seawater with 3.8 and 3.6*10−3. The two elements show an inverse correlation in bamboo coral skeletons. The mean apparent distribution coefficient of Na is similar to that of abiotic calcites. This similarity can be interpreted as the absence of significant vital effects for skeletal Na/Ca. Hence it corroborates the idea that the average skeletal composition of bamboo corals holds the potential to record past seawater conditions. In contrast, it appears unlikely that the spatial variations of the element distribution of seemingly simultaneously precipitated material along growth rings are exclusively controlled by environmental factors. We further exclude Rayleigh fractionation, ion-specific pumping, and Ca/proton exchange as the driver of Na and S distribution in bamboo corals. Instead, we adapt a calcification model originally proposed for scleractinians to bamboo corals. This model can explain the observed distribution of Na and S in the skeleton by a combination of Ca/proton pumping, bicarbonate active transport, and the formation of an organic skeletal matrix. The adapted model can further be used to predict the theoretical behaviour of other elements and disentangle vital effects from external factors influencing compositional features. It is therefore a useful tool for future studies on the potential of bamboo corals as environmental archives.

Description: The performance of herbivore consumers in freshwater ecosystems is influenced by food quality and quantity, which are crucial factors in understanding energy flow. However, the comprehensive effects of these factors on consumer growth based on natural food research remain unclear. To address this gap, we conducted a growth experiment culturing the Cladocera Daphnia similis in natural lake water collected from 30 subtropical lakes. Our results showed that the seston concentration (SC), seston phosphorus (seston P), and seston carbon: phosphorus ratio (seston C:P, in moles) were the most important factors in influencing the growth rate of D. similis according to the Random Forest model. Specifically, the growth rate of D. similis was significantly positive correlated with SC and seston P, and significantly negative correlated with seston C:P. D. similis exhibited the optimal growth performance within the seston C:P range of 32.8 to 69.8, with a sharp decline in growth rate observed at a break point of seston C:P of 70. The combined effect of food quality and quantity on growth rate was that higher SC (≥0.26 mg C/L), lower seston C:P (≤69.80), and higher P (≥0.11 mmol/g) were associated with significantly higher growth rates. Additionally, the growth rate increased significantly with the biomass of cryptophyte, indicating the importance of food composition. Our study shows that the growth rate of D. similis is co-affected by the quality and quantity of natural food. SC, seston C:P, seston P and algae composition are reliable indicators for assessing the growth rate of consumer in freshwater ecosystems. The inhibitory effect of low C:P on consumer growth should be applied with caution when assessing the development of herbivore consumers in natural lakes.

Description: Zooplankton communities vary in space and time. Their composition is strongly influenced by lower trophic levels that are dependent on the availability of light and nutrients. As all marine ecosystems are relying on zooplankton as intermediate trophic step between primary production and higher trophic levels, changes in the zooplankton community composition and biomass can cascade through the food web with important impacts on fish communities and through that on fisheries yields. An intense fisheries exist around the Falkland Islands in the SW Atlantic Ocean, around 51° S, but to the best of our knowledge, no previous study has to date investigated the seasonal variation in zooplankton community composition in these waters. We show that copepods (39.2%), the larvae of the anomurid Grimothea gregaria (33.1%) and euphausiids (10.9%) dominate the local mesozooplankton community by biomass. All species showed seasonal patterns, including ontogenetic behaviour of G. gregaria migrating to deeper waters with development, which were significantly explained by temperature (p 〈 0.001). While overall biomass significantly decreased with distance from shore (p 〈 0.001), mesozooplankton diversity was highest at 30 km from shore. The presented study is the first assessment of the mesozooplankton biomass off the Falkland Islands and provides a first baseline to aid future ecosystem studies in the context of ecosystem based fisheries management in the region.

Description: Water and sediment supply are essential to the health of deltaic ecosystems. Diverse datasets were integrated to better understand how climate change is shifting the supply of water and sediment to the largest polar distributary channel pattern – the Lena River Delta. Here the increase in warming rate from an average air temperature is from 4.1 °C for the period 1950–99 to 6.1 °C during 2000–21, which is higher than in the adjacent polar regions. Streamflow and sediment yield entering the Lena Delta have increased since 1988 by 56.3 km3 and 6.1×106 t, respectively; meanwhile, the Lena River’s increases in water temperature in June, July–August and September were found to be as much as 1.1, 0.6 and 0.05 °C. These changes have a pronounced effect on sediment regimes in particular parts of the delta. Based on analyses of correlations between various hydroclimatic drivers and sediment concentration changes across particular distributaries of the Lena Delta extracted from Landsat datasets, bank degradation driven by thermal erosional processes (which are in turn related to air and soil temperature increases) is proved to be the primary factor of the sediment regime in the delta. The study also highlights that sediment load changes are sensitive to wind speed due to remobilization of bottom sediment. Sums of daily air temperature and wind speed over 3 days are correlated with sediment concentration changes in the delta. The results also indicate that carbon transport across the delta (both POC and DOC) depends on sediment transport conditions and water discharge and might increase by up to 10 %. We conclude that the Lena Delta can be recognized as the global hot spot in terms of the hydrological consequences of climate change, which is altering sediment regimes, stream hydromorphology and carbon transport.

Description: It is a fundamental challenge to understand how the function of a network is related to its structural organization. Adaptive dynamical networks represent a broad class of systems that can change their connectivity over time depending on their dynamical state. The most important feature of such systems is that their function depends on their structure and vice versa. While the properties of static networks have been extensively investigated in the past, the study of adaptive networks is much more challenging. Moreover, adaptive dynamical networks are of tremendous importance for various application fields, in particular, for the models for neuronal synaptic plasticity, adaptive networks in chemical, epidemic, biological, transport, and social systems, to name a few. In this review, we provide a detailed description of adaptive dynamical networks, show their applications in various areas of research, highlight their dynamical features and describe the arising dynamical phenomena, and give an overview of the available mathematical methods developed for understanding adaptive dynamical networks.

Description: The understanding of the Earth’s magnetic field variations over time on the African continent is fundamental for several reasons. For instance, the most important feature of the present geomagnetic field, the South Atlantic Anomaly (SAA) characterized by weaker geomagnetic strength values than those expected for their latitudes, may have emerged in South Africa at the beginning of the second millennium CE. Here, we first selected the available volcanic and archaeomagnetic data following a set of three criteria inspired by the FAIR principles. We then built a first regional geomagnetic model for Africa covering the last 4000 years, using a revised version of the spherical cap harmonic (SCH) analysis in 2 dimensions. The new regional model shows, at the Earth’s surface, the westward migration of the SAA from the Indian Ocean over Africa since 1100 CE. In addition, the regional model is tested as a paleomagnetic dating tool by re-dating previous archaeomagnetic data from Africa and thus can be used to date other African archeological sites and the numerous active and dormant volcanoes of the East African System.

Description: Published

Description: 106855

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: JCR Journal

Description: In their paper, Spiess et al. (2021) published structural, geochronological, and EBSD data on one of the monzogranite apophyses (Capo Bianco) of the buried Porto Azzurro Pluton (island of Elba, Northern Apennines, Italy), a pluton emplaced in the upper crust (P 〈 0.2 GPa; e.g. Papeschi et al., 2019). The authors published a new U/Pb age of 6.4 ± 0.4 Ma, associated with the thermal peak, and a U-Th/He apatite age of 5.0 ± 0.6 Ma, indicating cooling below 60 ◦C. Spiess et al. (2021) use these ages to model the exhumation of the pluton controlled, in their model, by the Zuccale Fault, a subhorizontal fault with 6 km of eastward displacement (ZF; Keller & Coward, 1996). Their structural dataset from the macro to the microscale and EBSD analyses relies on a small section (about 100 m wide) in the NE part of the Calamita Peninsula. Based on their documentation of (1) vertical dykes in the monzogranite, (2) vertical to low-angle top-to-the-E extensional faults, and (3) later NWstriking oblique faults, they interpret the Porto Azzurro Pluton as emplaced in an extensional to transcurrent tectonic setting, extrapolating their findings to the entire Eastern Elba.

Description: Published

Description: 104499

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: Crystal zoning plays a fundamental role in modern volcanology as a key to unravel the geometry and the dynamics of plumbing systems. In this study, a detailed textural and compositional study of clinopyroxene crystals entrained in intrusive, hypabyssal and effusive products from Cima Pape (Dolomites) is coupled with thermobarometric-hygrometricmodels to reconstruct the geometry and evolution of the feeding systembeneath Middle Triassic volcanic edifices. Whole-rock major, trace element distribution and Sr-Nd isotopic signature (87Sr/86Sri = 0.7045–0.7050; 143Nd/144Ndi = 0.51223–0.51228) show that the rocks from Cima Pape are SiO2- saturated and have shoshonitic affinity, and likely belong to the acme of the Mid-Triassic magmatismthat shaped the Southern Alps between 239 and 237.6Ma. Highly porphyritic trachybasaltic to basaltic trachyandesitic volcanic rocks contain a large number of concentric-zoned clinopyroxene crystals. Here, high-Mg# and -Cr2O3, REEdepleted bands (Mg# 80–91; Cr2O3 up to 1.2 wt%) with variable thickness grew between relatively low-Mg# and -Cr2O3 (Mg# 70–77; Cr2O3 〈 0.1 wt%) augitic cores and rims. In contrast, the gabbroic to monzodioritic 50- to 300-m-thick sill cropping out belowthe volcanic sequences, though to represent a relic of the shallowest portion of the plumbing system, is mostly made up of unzoned clinopyroxene crystals. Thermobarometric and hygrometric models allowed us to define that a small “mush-type” batchwas located beneath the Cima Pape volcano at depths between 7 and 14 km. Here, augitic clinopyroxene formed in equilibrium with a slightly evolved (basaltic trachyandesitic), H2O-rich melt (Mg# = 43–45; T = 1035–1075 °C; H2O = 2.6–3.8 wt%). Periodic replenishments of the magma batch by primitive (Mg# = 65–70), hotter and relatively H2O-poor (T = 1130–1150 °C; H2O = 2.1–2.8 wt%) basaltic magmas led to the formation of diopsidic bands mantling the already formed augitic cores. Later on, re-equilibration of clinopyroxene with the mixed melt resulted in the formation of low-Mg#, LILE- and LREE-enriched rims. The most Mg-poor micro-phenocrystic clinopyroxene in the volcanic rocks and in the sill records the ultimate and shallowest conditions of crystallization, occurring at T of 975–1010 °C and P comprised between 50 and 150 MPa. Based on the presence of similar zoning in clinopyroxene phenocrysts, a comparison between the Mid-Triassic Cima Pape and active volcanoes was put forward to highlight the potential of studying ancient, entirely exposed volcanic systems for interpreting the feeding systemprocesses acting beneath active volcanoes. At a regional scale, this approach represents a new, powerful tool for investigating the evolution of the Mid-Triassic magmatism in the Southern Alps and shedding light on the interactions between mantle-derived melts and differentiated batches ponding in the crust.

Description: Published

Description: 107459

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: Trace metals and Rare Earth Element (REE) are amply discharged by submarine hydrothermal vents, sometimes leading to the formation of ore deposits of economic interest. We report on first data on the geochemical processes involving REE and trace metals, at the solid-liquid interface, in the hydrothermal area of Levante Bay at Vulcano Island (Aeolian Archipelago, Italy). Samples were collected from several submarine springs and seeps, a mud pool and one thermal well, and analyzed for Al, Si, Ti, V, Cr, Mn, Fe, Co, As, Rb, Sr, Cs, Ba, U and REE, besides major ions. Within the bay, hydrothermal fluids contaminate seawater and promote the leaching of metals from sediments through the dissolution of CO2 and H2S, while the particulate matter removes several elements from the water. The leaching of the bottom sediments and the contribution of steam-heated water produce an enrichment of some metals and REE in the Levante Bay with respect to the concentrations expected in the ambient seawater. An enrichment up to one order of magnitude is measured for Fe, Al, Ba, Cs and Rb, and up to two orders of magnitude for Mn in the submarine samples. Other transition metals (Ti, V, Co, Cr), U, As and Sr have concentrations similar or slightly lower than the ambient seawater. REE are in concentrations higher than in ambient seawater up to two orders of magnitude. Despite being significantly higher than uncontaminated seawater, the concentrations of some metals (namely Fe, Al, Ti, Cr, V, Co, U) and REE in most samples are lower than expected by the mixing between seawater and the steam-heated water, discharging from submarine springs. Indeed, equilibrium and reaction path modeling indicate the likely precipitation of Fe-oxyhydroxides, able to remove minor elements, such as Ti, Cr, Co, V and As, and REE. The last ones are significantly removed by newly-forming solid phases, due to the presence of a large amount of Fe released by the acidic fluids through the leaching of sediments. The low pH limits the formation of solution complexes of REE with carbonate ions (the main complexing agent for REE in seawater), whereas the sorption onto particles is still effective, even at close distance from the submarine springs and seeps. This study brings new insights on the geochemical processes occurring in submarine hydrothermal systems, in particular, those in subduction-related context.

Description: Fondo Sociale Europeo (PO FSE 2014-2020)

Description: Published

Description: 120756

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: Hydrogeological resources in the semiarid regions of Mexico support the economy and essential domestic activities of around 17 million people. However, adverse climatic conditions and overexploitation of aquifers affect the quantity and quality of the resource, added to problems of anthropogenic pollution and the salinity of water bodies. The Region Carbonífera aquifer represents the primary hydrogeological system in the most important coal-mining region in Mexico, located in the state of Coahuila. In this work, we present a complete dataset of 157 samples from surface and groundwaters sites have been used to characterizethe physicochemical and isotopic processes responsible for the composition of circulating waters, clarifying their origin, and to evaluate the water quality in terms of human consumption and irrigation use. The aquifer is mostly represented by Ca2+-Mg2+-SO42- and Ca2+-Mg2+-Cl- type waters, that supports salinization problems in 76% of the samples as well as sulfate excess. The origin of this chemical behavior seems to be the result of three main processes: 1) dissolution of soluble salts (gypsum, anhydrite and halite), 2) high surface evaporation under semiarid climate conditions, and 3) ionic and reverse ionic exchange. Processes 1 and 2 are also supported by the enrichment trends in the δ18O and δD signatures. For human consumption, 21% of the samples show high concentrations above the maximum permissible limits of the Official Mexican Standard (NOM-127-SSA1-1994) in total dissolved solids, Cl−, Na+, and SO42−. Additionally, 80% of the waters have some irrigation limitations due to excess sodicity or salinity. The worst quality waters for human or irrigation uses are located south of the aquifer in the municipalities of Juárez and Progreso. This study exhibits the complex hydric situation of the aquifer, raising awareness of the need to seek alternative sources, rational exploitation of resources, the use of crops that better adapt to these semiarid conditions, and intensifying hydrochemical monitoring in the region.

Description: Published

Description: 105307

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lozier, M., Bower, A., Furey, H., Drouin, K., Xu, X., & Zou, S. Overflow Water pathways in the North Atlantic. Progress In Oceanography, (2022): 102874, https://doi.org/10.1016/j.pocean.2022.102874.

Description: As part of the international Overturning in the Subpolar North Atlantic Program (OSNAP), 135 acoustically-tracked deep floats were deployed to track the spreading pathways of Iceland-Scotland Overflow Water (ISOW) and Denmark Strait Overflow Water (DSOW) from 2014 to 2018. These water masses, which originate in the Nordic Seas, are transported by the deepest branch of the Atlantic Meridional Overturning Circulation (AMOC). The OSNAP floats provide the first directly-observed, comprehensive Lagrangian view of ISOW and DSOW spreading pathways throughout the subpolar North Atlantic. The collection of OSNAP float trajectories, complemented by model simulations, reveals that their pathways are (a) not restricted to western boundary currents, and (b) remarkably different from each other in character. The spread of DSOW from the Irminger Sea is primarily via the swift deep boundary currents of the Irminger and Labrador Seas, whereas the spread of ISOW out of the Iceland Basin is slower and along multiple export pathways. The characterization of these Overflow Water pathways has important implications for our understanding of the AMOC and its variability. Finally, reconstructions of AMOC variability from proxy data, involving either the strength of boundary currents and/or the property variability of deep waters, should account for the myriad pathways of DSOW and ISOW, but particularly so for the latter.

Description: MSL gratefully acknowledges the support from the Physical Oceanography Program of the U.S. National Science Foundation (Grant OCE-2017522). ASB, HHF and SZ gratefully acknowledge the support from the Physical Oceanography Program of the U.S. National Science Foundation (Grant OCE-1756361). KLD gratefully acknowledges the support from the Physical Oceanography Program of the U.S. National Science Foundation (Grant OCE-1851075). XX gratefully acknowledges the support from the Physical Oceanography Program of the U.S. National Science Foundation (Grant OCE-2038449). RAFOS float data can be accessed at Woods Hole Open Access Server (https://doi.org/10.26025/1912/24388).

Description: We use the tidal deformations of the Moon induced by the Earth and the Sun as a tool for studying the inner structure of our satellite. Based on measurements of the degree-two tidal Love numbers $k_2$ and $h_2$ and dissipation coefficients from the GRAIL mission, Lunar Laser Ranging and Laser Altimetry on board of the LRO spacecraft, we perform Monte Carlo samplings for 120,000 possible combinations of thicknesses and viscosities for two classes of the lunar models. The first one includes a uniform core, a low viscosity zone (LVZ) at the core-mantle boundary, a mantle and a crust. The second one has an additional inner core. All models are consistent with the lunar t otal mass as well as its moment of inertia. By comparing predicted and observed parameters for the tidal deformations we find that the existence of an inner core cannot be ruled out. Furthermore, by deducing temperature profiles for the LVZ and an Earth-like mantle, we obtain stringent constraints on the radius (500 $\pm$ 1) km, viscosity, $(4.5 \pm 0.8) \times10^{16}$ Pa$\cdot$s and the density (3400 $\pm$ 10) kg/m$^3$ of the LVZ. We also infer the first estimation for the outer core viscosity, (2.07 ± 1.03) × 10$^{17}$ Pa·s, for tw o different possible structures: a Moon with a 70 km thick outer core and large inner core (290 km radius with a density of 6000 kg/m$^{3}$), and a Moon with a thicker outer core (169 km thick) but a denser and smaller inner core (219 km radius for 8000 kg/m$^{3}$).

Description: Published

Description: 115426

Description: 5IT. Osservazioni satellitari

Description: JCR Journal

Description: Intra-oceanic arcs are typically associated with intermediate (andesitic) cone volcanoes. However, caldera volcanoes may also form in these settings from very large eruptions, resulting in sudden changes to the magma reservoir. These reservoirs can then produce either semi-continuous or intermittent low-intensity volcanism between major caldera-producing or caldera-deepening eruptions, providing insights into the post-caldera evolution of the system. Hunga volcano (Kingdom of Tonga, Southwest Pacific) is a large mainly submarine edifice that produced a series of caldera-forming eruptions ~900 years ago. Since then, numerous smaller-scale subaerial and submarine eruptions occurred, the most recent forming new islands in 2009 and 2014/15. Pyroclastic deposits associated with these latest eruptions have identical (range ~ 0.1 wt% of all major oxides) andesitic composition that overlap with the primitive end of the slightly wider compositional range of the caldera-forming episodes. Texturally simple plagioclase, clinopyroxene and orthopyroxene phenocrysts in pre-, syn- and post-caldera pyroclasts point to a single shallow storage reservoir at 5–8 km depth. Lack of complex zonation indicates that this reservoir is constantly resupplied by low-flux inputs of basaltic andesite magma and is large enough that convective mixing rapidly homogenises new inputs. The reservoir feeds intermittent, low-intensity, post-caldera volcanism with constant andesite composition, driven possibly by magmatic overpressure and “leakage” of gas-rich magma pockets around the edges of the caldera. More primitive and compositionally variable basaltic andesites formed a lava-dominated edifice prior to the caldera-forming event. This suggests a causal link between magma supply dynamics and caldera priming relating to the maturing of the plumbing system and formation of a sustained subvolcanic andesite magma reservoir.

Description: This research was funded by the Faculty Research Development Fund, The University of Auckland to MB and SJC. We are grateful for financial and logistic support from ICON Films, Bristol, UK. We are especially grateful for the help and company of Lucy Meadows and Alex Holden, ICON Films, UK, during the field studies.

Description: Published

Description: 106614

Description: 1V. Storia eruttiva

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: Many vertical seismic velocity anomalies observed below different parts of the Eurasian plate are rooted in the transition zone between the upper and lower mantle (410–660 km), forming so-called secondary plumes. These anomalies are interpreted as the result of thermal effects of large-scale thermal upwelling (primary plume) in the lower mantle or deep dehydration of fluid-rich subducting oceanic plates. We present the results of thermo-mechanical numerical modelling to investigate the dynamics of such small-scale thermal and chemical (hydrous) anomalies rising from the lower part of the Earth’s upper mantle. Our objective is to determine the conditions that allow thermo-chemical secondary plumes of moderate size (initial radius of 50 km) to penetrate the continental lithosphere, as often detected in seismo-tomographic studies. To this end, we examine the effect of the following parameters: (1) the compositional deficit of the plume density due to the presence of water and hydrous silicate melts, (2) the width of the weak zone in the overlying lithosphere formed because of plume-induced magmatic weakening and/or previous tectonic events, and (3) a tectonic regime varied from neutral to extensional. In our models, secondary plumes of purely thermal origin do not penetrate the overlying plate, but flatten at its base, forming “mushroom”-shaped structures at the level of the lithosphere-asthenosphere boundary. On the contrary, plumes with enhanced density contrast due to a chemical (hydrous) component are shown to be able to pass upwards through the lithospheric mantle to shallow depths near the Moho when (1) the compositional density contrast is ≥ 100 kg m−3 and (2) the width of the lithospheric weakness zone above the plume is ≥ 100 km. An extensional tectonic regime facilitates plume penetration into the lithosphere but is not mandatory. Our findings can explain observations that have long remained enigmatic, such as the “arrow”-shaped zone of low seismic velocities below the Tengchong volcano in south-western China and the columnar (“finger”-shaped) anomaly within the lithospheric mantle discovered more than two decades ago beneath the Eifel volcanic fields in north-western Germany. It appears that a chemical component is a characteristic feature not only of conventional hydrous plumes located over presently downgoing oceanic slabs, but also of upper mantle plumes in other tectonic settings.

Description: Published

Description: 117819

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: Continental ultramafic rock systems, through the process of serpentinization, provide chemical and biochemical pathways that lead to the production of methane. The extent to which rock-water-gas reactions and organisms supply methane in these systems is a matter of considerable discussion and debate. Deciphering the interplay of abiotic and microbial methane observed at the surface requires several lines of reasoning as well as a variety of analyses. Despite using multiple models and interpretative tools, conclusions for the origin of methane at a particular site may vary or diverge from regional or global observations. Here, we critically address how possible conclusions of microbial versus abiotic methane in continental serpentinization systems may be interpreted and reinterpreted. We review fundamental concepts, advantages and limits, for three major methane origin models: (a) abiotic CO2 hydrogenation supplying gas reservoirs, (b) derivation from fluid inclusions in olivine-rich rocks, and (c) microbialgenesis in aquifers. We use the case of methane in the Samail ophiolite of Oman as an emblematic example of multiple interpretations; we identify ambiguous information offered by methane clumped isotopes and molecular gas compositions (e.g., the meaning of gaseous hydrocarbons heavier than methane), and suggest key tools, such as radiocarbon (14C) in methane, which may solve interpretative issues. The major constraint in any model of methane origin is the capability to sustain continuous gas flows, in terms of methane emission intensity, longevity and spatial extension, such as in natural gas sedimentary systems. Overall, this review suggests that any site interpretation can benefit from a holistic approach, integrating geochemical, geological and biological data with gas flow dynamics, as well as including regional and global contextualization.

Description: Published

Description: 105373

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: Sector-zoned clinopyroxene records kinetic effects imposed by variable degrees of magma undercooling, ΔT, and can be utilised to track the dynamics of magmatic systems. The partitioning of trace elements into sectors grown in different crystallographic orientations can be used as a proxy for ΔT. However, an experimental assessment of the relationship between trace element zoning and ΔT has been lacking to date. Here we present trace element data from a series of undercooling crystallisation experiments on a primitive trachybasalt from Mt. Etna (Italy), at conditions of crustal storage (400 MPa, NNO + 2), and ΔT ranging from 23 to 173 °C. Changes in ΔT were modulated by varying both resting and liquidus temperatures, the latter via the melt-H2O content of the experiments. The resting temperature was retained for 24 h to ensure the attainment of near-equilibrium conditions. High-resolution elemental mapping reveals the distribution of trace elements in individual clinopyroxene zones. Increasing ΔT drives a shift from polyhedral morphologies with Al-rich prism and Al-poor hourglass sectors (ΔT = 23–25 °C), to skeletal (ΔT = 75–123 °C) and dendritic (ΔT = 132–173 °C) crystals with Al-rich skeletons and Al-poor overgrowths. Aluminium-rich zones have higher concentrations of rare earth elements (REE) and high field strength elements (HFSE) than Al-poor zones across all investigated ΔT conditions, and overall, Al, REE and HFSE contents increase with ΔT. This indicates that tetrahedral aluminium (TAl) and associated charge-balancing mechanisms govern the incorporation of REE and HFSE within clinopyroxene. Lattice strain parameters for REE in the M2 site indicate the incorporation of light relative to heavy REE in clinopyroxene is controlled by competing effects between the strain-free partition coefficient, D0, and the optimum cation radius, r0. Critically, the middle and heavy REE switch from incompatible to compatible with increasing ΔT. Used to model fractional crystallisation, our data demonstrate that fractionation of clinopyroxene at low ΔT controls pre-eruptive melt evolution. Importantly, this indicates crystallisation of clinopyroxene in the deep portions of Mt. Etna’s plumbing system is not rapid and is unlikely to result in the early formation of dendrites. We develop a parameterisation of ΔT based on REE partitioning between experimental clinopyroxene and coexisting melt, which can be applied to sector-zoned augite crystallising from mafic alkaline magmas, to reconstruct dynamic processes and thermal pathways during magma transport and storage. Applied to sector-zoned clinopyroxene microphenocrysts and groundmass microcrysts from the 1974 eccentric eruption at Mt. Etna, our parameterisation tracks an increase in ΔT with magma ascent and eruption, following recharge of Cr-rich mafic magma at depth. Sector-zoned clinopyroxene can track ΔT variations leading to volcanism at Mt. Etna and could be applied to quantify magma dynamics in other active volcanoes.

Description: This work was supported by a Foundation Research Excellence Award from The University of Queensland (UQ-FREA RM2019001828, T.U.), the Advance Queensland Women’s Research Assistance Program from the Queensland Government (WRAP109-2019RD1 RM2020002371, T.U.) and the HP-HT laboratory of Experimental Geophysics and Volcanology (INGV, Rome). A.M. was supported by the Australian Government Research Training Program (RTP). S.M, M.M. and A.P. were supported by the MIUR project “Time scales of solidification in magmas: Applications to Volcanic Eruptions, Silicate Melts, Glasses, Glass- Ceramics” (PRIN 2017J277S9).

Description: Published

Description: 249-268

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: We compute a high-resolution topographic model of the Moho beneath the fault system activated during the 2016–2017 Central Italy seismic sequence, using Receiver Function (RF) analyses. We document that Ps conversions recorded in RF data-set varies abruptly at very short distance across the crustal lineament called Ancona-Anzio Line (AAL). Moho depth varies from about 25-30 km in the Tyrrhenian domain on the West to 35- 40 km in the Adriatic domain in the East. Where the two domains are juxtaposed along the AAL, Moho depth values cluster around 50 km depth, in a stripe-like area 20 km wide. Such unique feature marks the deformation zone in the lithosphere and testifies the abrupt change in delamination style in the two sectors of the Apennines. Intermittent large normal faulting earthquakes driven by across-belt extension break through such inherited strong structural changes, conditioned by localized barriers to fluids migration and overpressuring.

Description: Published

Description: 229237

Description: 1T. Struttura della Terra

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Volcanic plume aerosol following the paroxysmal event of Mount Etna (Italy) in February 21st - 26th, 2021 was detected in Naples area (Italy), together with transport of Saharan dust aerosol, combining lidar, sunphotometer and satellite observations with back-trajectories and dispersion models simulations. Lidar data allowed to clearly distinguish the two main aerosol components, to investigate the spectral dependence of the aerosol optical properties and to retrieve their microphysical properties, essential for a detailed aerosol characterization. A new Monte Carlo algorithm, capable of retrieving the particle size distribution from lidar measurements, was applied. Lidar results are in good agreement with columnar integrated sunphotometer data. This combination of novel lidar observations of the vertically-resolved aerosol microphysics, column observations and modelling allows for a more complete description of multi-layered aerosol conditions.

Description: Published

Description: 106099

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: Quantification of the subsurface geothermal potential primarily relies on the assessment of the thermal and mechanical configuration of the lithosphere. Such investigations require a detailed knowledge of the geological and tectonic forcing on the regional thermal, stress and hydraulic regimes and their counter feedback mechanisms. This approach becomes even more relevant in complex and active tectonic settings. In this regard, the Sicily region, which is located in the Central-Western Mediterranean, is an exceptional case study due to its almost unexplored geothermal potential hosted in a complex geodynamic setting. The present-day geological configuration resulted from the collision between the African and European plates, which led to the coexistence of compressional phases, beginning with the Oligocene-Miocene clockwise rotation of Corsica-Sardinia and alternated extensional phases in the Tyrrhenian basin due to the southward progression of the Sicilian- Maghrebian chain towards areas of the internal foreland (Hyblean domain). In this study, we attempt a reconstruction of the present-day lithospheric state of Sicily to quantify its thermal regime at shallow and intermediate depths. We have carried out a 3D lithospheric-scale gravity modelling in order to define the main geological units and their lithology-dependent rock properties, then integrated into a 3D geological model consistent with available borehole and seismic datasets. We have used the constructed geological model with its lithologydependent density, thermal conductivity, and radiogenic heat production to derive the present-day conductive thermal field as a whole and for individual tectonic or geological units, thereby considering different boundary conditions. We have finally validated results of the modelling against a shallow temperature dataset derived from hydrocarbon explorations. Our results indicate that the thermal field at depths shallower than 10 km is largely controlled by variability in sedimentary thickness in the foreland and the orogen, while deeper temperatures are primarily controlled by the distribution of the heat transferred from the mantle together with the radiogenic contribution of the shallow crystalline basement rocks and deeper crustal layers. The thermal modelling portrays a rather heterogenous Moho heat flow, locally higher than 80 mW/m2, revealing a particular geodynamic setting with specific areas characterized by high-to-medium enthalpy geothermal potential. As such, our modelling provides new perspectives for the exploration of geothermal resources in Sicily and helps to better constrain the thermal structure of the complex Sicilian collisional setting.

Description: Published

Description: 103976

Description: 1TR. Georisorse

Description: JCR Journal

Description: The Calabrian Arc represents one of the most active sectors of the upper plate of the Tyrrhenian-Ionian subduction system. This research aims to reconstruct the evolution of the Squillace Basin (Ionian offshore of the Calabrian Arc) from the Late Miocene to Recent times and recognise active shallow and deep structures using a multiscale approach. The latter is based on interpreting high-penetration and high-resolution seismic reflection profiles, calibrated with well-log data coupled with bathymetric data and the distribution of instrumental earthquakes. Data highlight three steps in the evolution of the Squillace Basin. A Late Miocene extensional event led to the formation of WNW-ESE oriented horst and half-graben structures. During the Pliocene, deformation was localised in the central and northern sectors of the basin and expressed by a WNW-ESE oriented strike-slip fault and NW-SE normal to trastensional faults, respectively. A transpressional event started in the Early Pleistocene, causing the positive inversion of deep (〉 3 km) extensional faults and the formation of NW-SE to WNW-ESE oriented transpressional/reverse faults and related anticlines. The kinematics of these faults agree with the NW-SE oriented left-lateral Albi-Cosenza, Lamezia-Catanzaro and Petilia-Sosti crustal fault zones developed in north Calabria. The results of this work suggest that the transpressional structures in the northwestern sector of the basin likely represent the offshore prolongation of the Albi-Cosenza fault zone. NW-SE to WNW-ESE trending, shallow (〈2 km) high-angle normal faults offset the younger deposits. Their depth and direction indicate that these faults are secondary structures formed in the extrados of the anticlines associated with the transpressional faults. The distribution of earthquakes shows events with M 〉 3 and depth 〈15 km located in the hanging wall of transpressional faults. The integrated data suggest that these structures are active and probably responsible for the major earthquakes that affected the Ionian offshore.

Description: Published

Description: 229772

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: Published in https://www.sciencedirect.com/science/article/pii/S0012821X22004617

Description: Earthquake forecasting and prediction have long and in some cases sordid histories but recent work has rekindled interest based on advances in early warning, hazard assessment for induced seismicity and successful prediction of laboratory earthquakes. In the lab, frictional stick-slip events provide an analog for earthquakes and the seismic cycle. Labquakes are ideal targets for machine learning (ML) because they can be produced in long sequences under controlled conditions. Recent works show that ML can predict several aspects of labquakes using fault zone acoustic emissions. Here, we generalize these results and explore deep learning (DL) methods for labquake prediction and autoregressive (AR) forecasting. DL improves existing ML methods of labquake prediction. AR methods allow forecasting at future horizons via iterative predictions. We demonstrate that DL models based on Long-Short Term Memory (LSTM) and Convolution Neural Networks predict labquakes under several conditions, and that fault zone stress can be predicted with fidelity, confirming that acoustic energy is a fingerprint of fault zone stress. We predict also time to start of failure (TTsF) and time to the end of Failure (TTeF) for labquakes. Interestingly, TTeF is successfully predicted in all seismic cycles, while the TTsF prediction varies with the amount of preseismic fault creep. We report AR methods to forecast the evolution of fault stress using three sequence modeling frameworks: LSTM, Temporal Convolution Network and Transformer Network. AR forecasting is distinct from existing predictive models, which predict only a target variable at a specific time. The results for forecasting beyond a single seismic cycle are limited but encouraging. Our ML/DL models outperform the state-of-the-art and our autoregressive model represents a novel framework that could enhance current methods of earthquake forecasting.

Description: Published

Description: 117825

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: The footwall of the surface rupturing Paganica normal fault, the source of the 2009 L’Aquila earthquake (Mw 6.1) in the Central Apennines (Italy), was investigated using integrated geological and geomorphological approaches. The aim was to constrain the active tectonics by studying the Raiale River that orthogonally crosscuts the fault trace, where it provides a useful geomorphological marker of long-term fluvial incision and footwall uplift. Using morphostratigraphy and paleomagnetic analysis, the Plio–Pleistocene morphotectonic evolution of the area was reconstructed, comprising an ancient continental basin and paleolandforms that predate the footwall incision. Starting from the Late Early Pleistocene–Middle Pleistocene, fluvial dissection was mainly due to marked river downcutting triggered by significant activity of the Paganica Fault, which caused progressive base-level lowering. The Raiale River downcutting formed five Middle–Late Pleistocene fluvial terraces, that, along with absolute Optically Stimulated Luminescence (OSL) dating, allowed the identification of paleolongitudinal profiles with a diverging downstream configuration. Terrace dating yielded a minimum incision rate of 0.25 ± 0.02 mm/a, which only partially compensates the footwall uplift and can thus be considered as a minimum value for the Paganica Fault throw rate, which could reach up to ~0.45 mm/a. In parallel, using terrestrial cosmogenic nuclides, a denudation rate of 0.02–0.04 mm/a was measured on the summit of the footwall block. This denudation is in keeping with the drainage incision, suggesting a non-steady state for the fault footwall topography and a dominance of relief growth. Last, the analysis of the modern Raiale River longitudinal profile denoted an ungraded status, with two main knickzones that we interpret as transient forms due to tectonic perturbations, likely triggered by activity of the Paganica Fault during the end Early Pleistocene and the Late Pleistocene. Considering the 2009 L’Aquila earthquake coseismic rupture, we observe that the younger transience on the Raiale River longitudinal profile, if it is of tectonic origin, could have only been produced by much larger seismic events (i.e., Mw 〉 6.5) than those documented in the area by paleoseismological investigations. The collective results confirmed that in the Central Apennines, conditions of dynamic equilibrium are often not met, and that the persistence of transient perturbations induced by tectonics should be accounted for.

Description: The work was financially supported by the MIUR (Italian Ministry of Education, University and Research) project “FIRB Abruzzo - High-resolution analyses for assessing the seismic hazard and risk of the areas affected by the 6 April 2009 earthquake”, ref. RBAP10ZC8K_005 and RBAP10ZC8K_007, and by Agreement INGV-DPC 2012-2021. The airborne LiDAR survey performedby the Civil Protection of Friuli Venezia Giulia (Italy) was kindly released by Italian Civil Protection Department Special thanks to Simone Atzori, who provided the InSAR data.

Description: Published

Description: 108411

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: In seismically active regions with variable dominant focal mechanisms, there is considerable tsunami inundation height uncertainty. Basic earthquake source parameters such as dip, strike, and rake affect significantly the tsunamigenic potential and the tsunami directivity. Tsunami inundation is also sensitive to other properties such as bottom friction. Despite their importance, sensitivity to these basic parameters is surprisingly sparsely studied in literature. We perform suites of systematic parameter searches to investigate the sensitivity of inundation at the towns of Catania and Siracusa on Sicily to changes both in the earthquake source parameters and the Manning friction. The inundation is modelled using the Tsunami-HySEA shallow water code on a system of nested topo-bathymetric grids with a finest spatial resolution of 10 m. This GPU-based model, with significant HPC resources, allows us to perform large numbers of high- resolution tsunami simulations. We analyze the variability of different hydrodynamic parameters due to large earthquakes with uniform slip at different locations, focal depth, and different source parameters. We consider sources both near the coastline, in which significant near-shore co-seismic deformation occurs, and offshore, where near- shore co-seismic deformation is negligible. For distant offshore earthquake sources, we see systematic and intuitive changes in the inundation with changes in strike, dip, rake, and depth. For near-shore sources, the dependency is far more complicated and co- determined by both the source mechanisms and the coastal morphology. The sensitivity studies provide directions on how to resolve the source discretization to optimize the number of sources in Probabilistic Tsunami Hazard Analysis, and they demonstrate a need for a far finer discretization of local sources than for more distant sources. For a small number of earthquake sources, we study systematically the inundation as a function of the Manning coefficient. The sensitivity of the inundation to this parameter varies greatly for different earthquake sources and topo-bathymetry at the coastline of interest. The friction greatly affects the velocities and momentum flux and to a lesser but still significant extent the inundation distance from the coastline. An understanding of all these dependencies is needed to better quantify the hazard when source complexity increases.

Description: Published

Description: 757618

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami

Description: 1SR TERREMOTI - Sorveglianza Sismica e Allerta Tsunami

Description: 3IT. Calcolo scientifico

Description: JCR Journal

Description: The present investigation provides measurements of radon (222Rn) concentration levels in 20 thermal waters at the Campi Flegrei volcanic caldera, an important geothermal system with hydrothermal manifestations in the Neapolitan area (Southern Italy). We used a RAD7® Radon-in-air detector equipped with Big Bottle RAD H2O and DRYSTIK accessories (Durridge Co. Inc.). Water samples with different chemical and/or physical conditions, not used as drink waters, are taken from continental thermal groundwaters, springs, lakes, pools and one sub merged thermal spring. The waters are mostly chlorine to bicarbonate, except of a few sulphate types sampled at the hydrothermal discharge areas of Solfatara and Pisciarelli, central in the caldera. Water temperature and pH values range from 18.1 to 91.3 ◦C and from 2 to 8, respectively. Sampling and measurement of radon in groundwater are complicated by the high volatility of the gas; a method is here proposed. In some of the 20 sites double or triple samples were collected by using different volume polyethylene terephthalate (PET) bottles, diluting sample with blank water, and modifying flow of pumped wells. We suggest that dilution can be considered when water is i) not enough to fill in the PET, resulting in large head space in the sampler, ii) too hot determining damage of the PET or iii) too saline to clog the Big Bottle System. Dissolved radon concentrations vary from 0.1 ± 0.1 to 1146 ± 57 Bq/L with an average value of 152 Bq/L, using the CAPTURE program, the default RAD7 data acquisition program. Similar values in radon concentration are obtained using the method proposed in De Simone et al. (2015) ranging between 0.1 ± 5.8 and 1286 ± 98 Bq/L with an average value of 167 Bq/L. The hottest and most acidic sulphate waters refer to a small boiling pool at Pisciarelli hydrothermal discharge area and have nearly zero 222Rn content. 222Rn concentrations from this study are mostly below the reference level of 1000 Bq/L recommended for human health protection by the European Commission and the most adopted in the scientific community (Catao ˜et al., 2022). No correlation has been observed between temperature, pH, major anions and radon content values, nor between rock composition since it is almost homogeneous trachyte at the study sites. 222Rn levels therefore appear to reflect the local sedimentological, structural or hydrogeological conditions. The levels of 222Rn here presented are an important background for the scientific community that will intend to define the natural fluctuations of dissolved 222Rn in relation with seasons, environment, hydrogeology or volcanic dynamics at the geohazardous Campi Flegrei area.

Description: Published

Description: 107641

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: 6SR VULCANI – Servizi e ricerca per la società

Description: JCR Journal

Description: The δ18O and δ2H of rivers and springs were investigated in order to characterize the groundwater recharge sources around Nyiragongo and Nyamulagira volcanoes, in the Democratic Republic of the Congo and Rwanda. Water samples were collected monthly between November 2013 and October 2014 from 5 major rivers, 3 major cold springs, 3 tepid springs and 1 hot spring. The temperatures of each spring were nearly constant over the sampling period attesting for their groundwater character, while the temperatures of the rivers were much more variable. The rivers monthly δ2H and δ18O range from 􀀀 6.8‰ to 1.9‰ and 􀀀 3.1‰ to 1.6‰, respectively, while springs showed depleted values that span from 􀀀 10.2 to 􀀀 1.1‰ for δ2H and 􀀀 3.6 to 􀀀 1.9‰ for δ18O. Catchment morphology (formed of depression, upper footslope and medium to high gradient-mountains) and the local tectonic discontinuity (fissures and faults) regulate the surface runoff and subsurface flow, control the precipitation infiltration zones and hence the aquifers recharge areas. Chemical and isotopic (δ18O and δ2H) compositions of springs and rivers reveal the presence of shallow and deep aquifers, with some waters having intermediate isotope composition. Three different recharge zones characterized by different altitudes were identified: the first is found at low altitude ranging from ~1800 m to ~2150 m, the second and intermediate recharge zone in the altitude range from ~2180 m to ~2500 m at the upper footslope area, while the third and highest recharge area is located in the altitudes range from ~2620 to ~3220 m. The two upper recharge areas are the most fractured and fissured zones allowing rapid infiltration of depleted precipitations which recharge deep aquifers found in the tepid and hot springs. Based on their chemical and isotopic composition, waters from the shallow and deep aquifers have been considered representative of mixing end members. During their ascent to the surface, water from the deep aquifer mixes with that of shallow aquifer yielding the tepid springs of intermediate chemical and isotopic composition, while the other keep their original fingerprint corresponding to the isotopically depleted hot spring.

Description: Published

Description: 120778

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: Implicit integration of the viscous term can significantly improve performance in computational fluid dynamics for highly viscous fluids such as lava. We show improvements over our previous proposal for semi-implicit viscous integration in Smoothed Particle Hydrodynamics, extending it to support a wider range of boundary models. Due to the resulting loss of matrix symmetry, a key advancement is a more robust version of the biconjugate gradient stabilized method to solve the linear systems, that is also better suited for parallelization in both shared-memory and distributed-memory systems. The advantages of the new solver are demostrated in applications with both Newtonian and non-Newtonian fluids, covering both the numerical aspect (improved convergence thanks to the possibility to use more accurate boundary model) and the computing aspect (with excellent strong scaling and satisfactory weak scaling).

Description: Published

Description: 111413

Description: 3IT. Calcolo scientifico

Description: JCR Journal

Description: The evolution of High-Performance Computing (HPC) platforms enables the design and execution of progressively larger and more complex workflow applications in these systems. The complexity comes not only from the number of elements that compose the workflows but also from the type of computations they perform. While traditional HPC workflows target simulations and modelling of physical phenomena, current needs require in addition data analytics (DA) and artificial intelligence (AI) tasks. However, the development of these workflows is hampered by the lack of proper programming models and environments that support the integration of HPC, DA, and AI, as well as the lack of tools to easily deploy and execute the workflows in HPC systems. To progress in this direction, this paper presents use cases where complex workflows are required and investigates the main issues to be addressed for the HPC/DA/AI convergence. Based on this study, the paper identifies the challenges of a new workflow platform to manage complex workflows. Finally, it proposes a development approach for such a workflow platform addressing these challenges in two directions: first, by defining a software stack that provides the functionalities to manage these complex workflows; and second, by proposing the HPC Workflow as a Service (HPCWaaS) paradigm, which leverages the software stack to facilitate the reusability of complex workflows in federated HPC infrastructures. Proposals presented in this work are subject to study and development as part of the EuroHPC eFlows4HPC project.

Description: Published

Description: 414-429

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami

Description: 4V. Processi pre-eruttivi

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: 3IT. Calcolo scientifico

Description: JCR Journal

Description: Aquaculture represents an important source of food and it plays an important role in terms of contribution to economic development. Offshore farming offers considerable advantages, especially in terms of production costs (lower than those of onshore facilities) and of farmed product quality. Suitable areas for aquaculture activities are still available in Italy but are increasingly limited and the demand for new farms is high. The lack of coastal areas allocated to aquaculture and the complex regulatory and legal framework constitutes the major constraints for further development of the sector. Zoning is the process that can allow to sustainably identify and allocate suitable areas for aquaculture. Several aspects, such as effective legal framework and procedures, collection of bio-geochemical, physical and socio-economical information, are crucial for a correct aquaculture zoning process in order to identify the Allocated Zones for Aquaculture (AZAs). In the present work, a spatial multi-criteria decision analysis (SMCDA) was applied for the individuation of potentially suitable marine areas for fish farming across the southern Tyrrhenian coast of Tuscany (Italy). The spatial model was developed by collecting and processing Earth Observation (EO) data, oceanography in situ measurements, and infrastructural and environmental constraints. Excluding areas of constrains, obtained results highlight that 96% of the total investigated area is characterised by medium (62%) and high (34%) suitability. In particular, the highest suitability areas occur in the Talamone gulf and offhore the Argentario promontory at water depth between 15-30 m and 30 50m, respectively. Other high suitability areas occur northern of Piombino town between 30-100 m depth. Environmental data at higher spatial resolution are needed to improve aquaculture zoning and further process of site selection in order to ensure the sustainability of fish farming in the study area.

Description: Published

Description: 106261

Description: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare

Description: JCR Journal

Description: A multidisciplinary study of a sector of the Ionian coastal belt, southern Italy, mainly based on two new bore holes approximately 25 m (MSA) and 20 m (MSB) deep, was carried out in the frame of a wider geo archaeological project. Stratigraphic and Paleoecological data, together with geomorphological observations, have been used in order to define the Late Quaternary morpho-sedimentary evolution and its relationships with tectonic and climate forcing. The analyses of core sediments and geomorphic interpretations allowed us to reconstruct the changes in depositional setting and physical landscape starting from the MIS 5.5. To this scope, new data about sedimentary facies, benthic foraminifera and ostracod assemblages, and a set of 14C ages spanning from about 33 to 15 kyr BP are here presented. All these data revealed a strong modification of the depositional setting within the coastal plain, as inferred by the presence of marine, transitional, and continental deposits, and suggest an anomalous position of sea-level reference points. Such anomalies are clustered in two homogenous arrays that can be explained only admitting a significant tectonic uplift in recent times (i.e. about 4 mm/yr over the last 15,000 years).

Description: Published

Description: 84-110

Description: 4A. Oceanografia e clima

Description: 7SR AMBIENTE – Servizi e ricerca per la società

Description: JCR Journal

Description: The sedimentological, lithological and textural characteristics of the Brown Tuffs (BT) pyroclastic deposits, combined with their grain-size, componentry and geochemical glass compositions, are here investigated to obtain information on the transport and depositional mechanisms of the corresponding pyroclastic density currents (PDCs). The BT are widespread reddish-brown to grey, ash-rich pyroclastic deposits generated by pulsating hydromagmatic explosive activity from the La Fossa Caldera on Vulcano island during the c. 80–6 ka time-stratigraphic interval, and then distributed on most of the Aeolian Islands and Capo Milazzo peninsula (Sicily) and in the Tyrrhenian and Adriatic Sea regions. Near the source area on Vulcano, the BT are characterised by alternating massive and planar to cross stratified lithofacies that result from the stepwise, repeating aggradation of discrete PDC pulses. This alternance is regulated by either fluid escape or granular flow depositional regimes at high clast concentration or grain by grain traction deposition in thewaning diluted stages of the PDCs. Most of the BT on Vulcano showintermittently stratified and massive ash deposits resulting froma pervasive post-depositional disruption of the primary structures. This is induced by upward fluid expulsion associated with dissipation of pore pressure between layers at different grain size (fine to coarse ash) and porosity, as outlined by distinctive upwards bends and pillar-type escape structures through the fluid-filled cracks and rupture points. Massive BT deposits with a faint colour and grain-size banding are widely recognised on Lipari, the nearby island of Vulcano. Based on the presence, at the base of BT depositional units, of cm-thick amalgamation bands containing pumice lapilli, scoria and lithic clasts ripped-up and embedded from the loose underlying pyroclastic units, they are interpreted as deposited by ash-rich PDCs laterally spreading from La Fossa Caldera and moving to Lipari.During their motion to Lipari these currents (likely) crossed a narrow and shallow sea-water inlet which did not stop their advancement but influenced the grain size distribution of those spreading on the Lipari mainland. In this paper, the mechanism of clast erosion and incorporation is outlined across the whole island of Lipari by means of field study, grain-size, and geochemical glass analyses on the different components of the mixed basal bands of the BT. This suggests that the BT PDCs maintained enough flow power as to erode the substratum, hence likely impacting the territory, over a distance up to at least 16–17 km from the volcanic source. Evidence that the BT PDCs exerted a high shear-stress over the loose substratum is also provided by undulated, recumbent flame and rip-up structures at the base of some depositional units in southern and central Lipari. In order to form such bed granular instabilities between the BT and the underlying deposits we calculate that the currents had at least a shear velocity of ca. 2 m s−1 and a shear stress in the range of 1‐4.5 kPa. These results add new insights on the large-scale hazard at the Aeolian Islands and shed new lights on the widespread transport and depositional dynamics of ash flows spreading over the sea and reaching nearby islands, and their interactions with the substratum and the pre-depositional topography. The sedimentological, lithological and textural characteristics of the Brown Tuffs (BT) pyroclastic deposits, combined with their grain-size, componentry and geochemical glass compositions, are here investigated to obtain information on the transport and depositional mechanisms of the corresponding pyroclastic density currents (PDCs). The BT are widespread reddish-brown to grey, ash-rich pyroclastic deposits generated by pulsating hydromagmatic explosive activity from the La Fossa Caldera on Vulcano island during the c. 80–6 ka time-stratigraphic interval, and then distributed on most of the Aeolian Islands and Capo Milazzo peninsula (Sicily) and in the Tyrrhenian and Adriatic Sea regions. Near the source area on Vulcano, the BT are characterised by alternating massive and planar to cross stratified lithofacies that result from the stepwise, repeating aggradation of discrete PDC pulses. This alternance is regulated by either fluid escape or granular flow depositional regimes at high clast concentration or grain by grain traction deposition in thewaning diluted stages of the PDCs. Most of the BT on Vulcano showintermittently stratified and massive ash deposits resulting froma pervasive post-depositional disruption of the primary structures. This is induced by upward fluid expulsion associated with dissipation of pore pressure between layers at different grain size (fine to coarse ash) and porosity, as outlined by distinctive upwards bends and pillar-type escape structures through the fluid-filled cracks and rupture points. Massive BT deposits with a faint colour and grain-size banding are widely recognised on Lipari, the nearby island of Vulcano. Based on the presence, at the base of BT depositional units, of cm-thick amalgamation bands containing pumice lapilli, scoria and lithic clasts ripped-up and embedded from the loose underlying pyroclastic units, they are interpreted as deposited by ash-rich PDCs laterally spreading from La Fossa Caldera and moving to Lipari. During their motion to Lipari these currents (likely) crossed a narrow and shallow sea-water inlet which did not stop their advancement but influenced the grain size distribution of those spreading on the Lipari mainland. In this paper, the mechanism of clast erosion and incorporation is outlined across the whole island of Lipari by means of field study, grain-size, and geochemical glass analyses on the different components of the mixed basal bands of the BT. This suggests that the BT PDCs maintained enough flow power as to erode the substratum, hence likely impacting the territory, over a distance up to at least 16–17 km from the volcanic source. Evidence that the BT PDCs exerted a high shear-stress over the loose substratum is also provided by undulated, recumbent flame and rip-up structures at the base of some depositional units in southern and central Lipari. In order to form such bed granular instabilities between the BT and the underlying deposits we calculate that the currents had at least a shear velocity of ca. 2 m s−1 and a shear stress in the range of 1‐4.5 kPa. These results add new insights on. the large-scale hazard at the Aeolian Islands and shed new lights on the widespread transport and depositional dynamics of ash flows spreading over the sea and reaching nearby islands, and their interactions with the substratum and the pre-depositional topography.

Description: Published

Description: 106040

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: This work deals with a comprehensive multiparametric and multilayer approach to study earthquake-related processes that occur during the preparation phase of a large earthquake. As a case study, the paper investigates the M7.2 Kermadec Islands (New Zealand) large earthquake that occurred on June 15, 2019 as the result of shallow reverse faulting within the Tonga-Kermadec subduction zone. The analyses focused on seismic (earthquake catalogs), atmospheric (climatological archives) and ionospheric data from ground to space (mainly satellite) in order to disclose the possible Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). The ionospheric investigations analysed and compared the Global Navigation Satellite System (GNSS) receiver network with insitu observations from space thanks to both the European Space Agency (ESA) Swarm constellation and the China National Space Administration (CNSA in partnership with Italian Space Agency, ASI) satellite dedicated to search for possible ionospheric disturbances before medium-large earthquakes, i.e. the China Seismo-Electromagnetic Satellite (CSES-01). An interesting comparison is made with another subsequent earthquake with comparable magnitude (M7.1) that occurred in Ridgecrest, California (USA) on 6 July of the same year but in a different tectonic context. Both earthquakes showed anomalies in several parameters (e.g. aerosol, skin temperature and some ionospheric quantities) that appeared at almost the same times before each earthquake occurrence, evidencing a chain of processes that collectively point to the moment of the corresponding mainshock. In both cases, it is demonstrated that a comprehensive multiparametric and multilayer analysis is fundamental to better understand the LAIC in the occasion of complex phenomena such as earthquakes.

Description: Published

Description: 113325

Description: 7T. Variazioni delle caratteristiche crostali e "precursori"

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: 2A. Fisica dell'alta atmosfera

Description: JCR Journal

Description: In this work, we document two distinct tsunami deposits on the coasts of Ios Island, Aegean Sea, Greece. The younger tsunami deposit, dated 1831–1368 cal. BCE, includes both marine sediments and pumices from the ∼1600 BCE Minoan eruption of Santorini volcano. This is the first evidence of the Minoan tsunami in the Cycladic Islands North of Santorini. Tsunami waves inundated the Manganari coastal plain, southern coast of Ios, over a distance 〉200 m (〉2 m a.s.l.). The second tsunami deposit reworks pumice from the 22 ka Cape Riva eruption mixed with marine sediment. We assume a Neolithic age for this major tsunami, with a wave runup 〉13 m a.s.l. on the southern and eastern coasts of Ios. The source of this tsunami - volcanic eruption, landslide, or earthquake - remains unknown. Additionally, we provide the first on-land evidence of Cape Riva deposits outside Santorini, thus questioning previous estimates on the magnitude of this eruption.

Description: Published

Description: 106908

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: The mechanism governing the kinetic growth of olivine in dynamic volcanic settings has been the subject of considerable attention in recent years. Under variable cooling rate (CR) and undercooling (􀀀 ΔT) regimes, the textual maturation of olivine proceeds from skeletal/dendritic crystals to polyhedral morphologies by infilling of the crystal framework. Owing to the establishment of a diffusion-controlled growth regime, a sharp diffusive boundary layer develops in the melt next to the advancing olivine surface. In this context, we have quantified the apparent partitioning of Ti, Al, P, and Cr between olivine and a Hawaiian tholeiitic basaltic melt at P = 1 atm, fO2 = QFM-2 buffer, and CR = 4, 20, and 60 ◦C/h over a constant -ΔT = 85 ◦C. Differences in charge and/or size between the substituent minor cations and the major species in the olivine crystallographic site dominate the energetics of homovalent and heterovalent cation substitutions. While the entry of Ti in the olivine lattice site accounts for the simple exchange [TSi4+] ↔ [TTi4+], more complex charge-balancing coupled-substitution mechanisms have been determined for the incorporation of Al, P, and Cr, i.e., [MMg2+, TSi4+] ↔ [MAl3+, TAl3+], [2 TSi4+] ↔ [TP5+, TAl3+], and [MMg2+, TSi4+] ↔ [MCr3+, TAl3+], respectively. In order to maintain charge balance, the disequilibrium uptake of minor cations in rapidly growing crystals is controlled by the same substitution mechanisms observed under equilibrium crystallization. This finding is consistent with the achievement of a local interface equilibrium at the olivine-melt interface independently of the diffusive boundary in the melt. A statistical approach based on multivariate analysis of olivine/melt compositional parameters confirms that the control of melt structure on the partitioning of Ti, Al, P, and Cr is almost entirely embodied in the olivine structure and chemistry via charge compensation reactions. Therefore, the magnitude of minor element partition coefficients is weakly dependent on diffusion kinetics in the melt but rather strongly governed by olivine zoning patterns resulting from fast crystal growth rates.

Description: Published

Description: 120870

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: JCR Journal

Description: The gradual temporal shift of the spectral lines of harmonic seismic and/or acoustic tremor, known as spectral gliding, has been largely documented at different volcanoes worldwide. Despite the clear advantage of the experimental approach in providing direct observation of degassing processes and related elastic radiation, experimental studies on gliding tremor are lacking. Therefore, we investigated different episodes of gliding of acoustic and seismic tremor observed during analogue degassing experiments performed under different conditions of magma viscosity (10-1,000 Pa s), gas flux (5-180×10−3 l/s) and conduit surface roughness (fractal dimension of 2-2.99). Gliding experimental harmonic seismic and acoustic tremor was observed at high gas flux rates and viscosities, mostly associated with an increasing trend and often preceding a major burst. Decreasing secondary sets of harmonic spectral lines were observed in a few cases. Results suggest that gliding episodes are mostly related to the progressive volume variation of shallow interconnected gas pockets. Spectral analyses performed on acoustic signals provided the theoretical length of the resonator that was compared against the temporal evolution of the gas pockets, quantified from video analyses. The similarities between the observed degassing regime and churn-annular flow in high viscous fluids encourage further studies on churn dynamics in volcanic environments.

Description: Published

Description: 117344

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: We report on the characterization of a thick sequence of pyroclastic deposits exposed on the summit area and flanks of Mount Melbourne volcano, in northern Victoria Land, Antarctica related to eruptions during the Late Glacial period. We provide a complete characterization of tephra deposits including mineralogy, single shard major- and trace-element glass compositions, and an 40Ar-39Ar age of feldspar crystals extracted from the deposit. The pyroclastic deposits are trachybasaltic to trachytic in composition and are interpreted to have resulted from four Strombolian/Vulcanian to sub-Plinian/Plinian eruptions. The younger and more intense sub-Plinian/Plinian eruption (our eruption 2) yielded an 40Ar-39Ar age of 13.5 ± 4.3 ka (±2σ). The study of Mount Melbourne proximal deposits provides significant new data for the reconstruction of the volcano eruptive history and a better assessment of the volcanic risk connected to a possible future eruption. We also explore geochemical correlations between Mount Melbourne proximal deposits and distal tephra layers recognized in ice cores and blue ice fields of East Antarctica. A good geochemical match exists between the composition of products from the trachytic sub-Plinian/Plinian eruption 2 and some tephra layers from Talos Dome and shards in Siple Dome which is also compatible in age (c. 9.3 ka) with our 40Ar-39Ar age determination. Our new insights into the volcanic history of Mount Melbourne and the new high-quality electron microprobe and trace element composition data on its proximal products will help improve future correlations and synchronization of tephra archives in the region.

Description: Published

Description: 107457

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: This paper deals with the well-known mismodelling characterizing the NeQuick topside ionosphere at low latitudes, i.e., the fact that the model keeps the two electron density humps typical of the equatorial ionization anomaly as the altitude increases from the height of the F2-layer electron density peak, without merging them in a single peak above the geomagnetic equator as expected. This is because the NeQuick topside ionosphere modelling strongly depends on several bottomside ionosphere parameters, which causes an essential coupling between the topside and the bottomside that in many cases behave differently. This means that this kind of topside ionosphere modelling may lead to inaccurate results, as it is the maintenance at low latitudes of the electron density double hump structure in the topside as the altitude increases. On the base of some recently published results, this paper analyzes the role played by the three NeQuick scale height parameters H0, g and r in the description of the electron density above the F2 layer peak height. The results of this work pave the way for a possible solution of this low-latitude NeQuick topside ionosphere mismodelling.

Description: Published

Description: 1224-1236

Description: 2A. Fisica dell'alta atmosfera

Description: JCR Journal

Description: The 4.5 ka trachytic Plinian eruption of Agnano-Monte Spina is the largest magnitude event of the past 5 ka at Campi Flegrei caldera. The complete eruptive sequence consists of six members, three of which, named A, B and D, are characterized by the association of fallout and pyroclastic density current (PDC) deposits well preserved at proximal locations. In this study, we analyze the textural characteristics of the pumice clasts of the three major fallout deposits (A1, B1, D1) and of their associated PDC deposits (A2, B2, D2), and link them to the physical properties of magma in order to investigate conduit fluid dynamics. A combination of data (field work, grain-size and density measurements, vesicle number densities and size distributions, crystal content, water content) is used to set up the source term conditions for numerical simulations. Each fall/PDC transition is accompanied by distinctive changes in textural properties of the juveniles, recognized by a lowering in vesicle number densities of about one order of magnitude (from 108 to 107 cm−3), indicating a significant decrease in the magma ascent rate. Melt inclusions show a marked decrease in volatile content recurrent at each fall/PDC transition and indicate that the three main pulses of the eruption were fed by distinct and progressively deeper magma batches. Numerical simulations, taking into account magma properties derived from the textural analyses, and variations in initial water content, show decreases in the exit velocities and Mass Discharge Rate (MDR) consistent with such fall/PDC transitions. Different initial water contents together with changes in conduit diameters allow us to simulate the different column heights reconstructed for the three Plinian phases. The reconstructed scenario for the Agnano-Monte Spina eruption involves a stop-start behavior and a top-down trigger for the most voluminous and intense eruptive episode D.

Description: Published

Description: 119301

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: The development of structurally controlled basins is frequently dominated by inherited geological and tectonic structures, especially when the affected region has undergone multiple tectonic phases. In this study we use physically scaled analog models to analyze the impact of inherited faults on the evolution of a new extensional fault system and its associated basin. In our experiments, we introduced inherited faults – bearing diverse geometries and orientations – cut through a homogeneous analog material (wet clay). After each experiment, we compare (a) how the inherited faults affected the inception and development of new faults and (b) the shape of the resulting basins, using a ‘reference model’ run without pre-existing faults. The results show that the orientation of pre-existing faults with respect to the extensional axis does affect the development of the new extensional structures. The main effects show up when the orientation of the pre-existing faults is closer to that expected for a fault that is optimally oriented (perpendicular) with respect to the direction of extension and has a dip close to an Andersonian extensional fault. Conversely, the impact on the resulting basin shape is more spatially complex, especially in the case of misoriented pre-existing faults. We also compare our experimental results with an analytical method based on the slip tendency theory. The application of our findings to selected natural cases demonstrates how one may interpret the occurrence, orientation, and activity of inherited faults by looking at the present-day geometry and wavelength of an extensional basin, particularly when newly formed extensional faults exhibit structurally unexpected trajectories.

Description: Part of this work was funded by the project “The impact of an inherited structural setting on the development of extensional systems in the Amatrice-Norcia-Visso area: insights from analog modeling” (UR 0865.050; P.I.: Umberto Fracassi), part of the INGV-FISR 2016 Project - Italia centrale “Centro di studio e monitoraggio dei rischi naturali dell'Italia centrale” (cod. D82F16001180001), and by the INGV “FASTMIT” Project (UR 0850.010; P.I.: Roberto Basili – cod. D52F16001150001).

Description: Published

Description: 104836

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: This work pursues the hydro-geochemical and isotopic characterization of the complex groundwater system of the Gioia Tauro Plain, one of the most important industrialized and agricultural coastal areas of southern Italy. The anthropic pressure exposes the water resources at risk of depletion and quality degradation making the plain groundwater a system of high scientific and social interest. The plain is characterized by a shallow aquifer, mostly recharged by local rains and a deep aquifer apparently less influenced by local precipitation. Both aquifers are mainly Ca-HCO3 waters except for localized sectors where Na-HCO3, Na-Cl and Ca-SO4 waters are present. In deep aquifer, both prolonged interaction with sedimentary rocks, mainly deriving from the erosion of crystalline rocks, and direct cation exchange represent the primary factors controlling the formation of Na-HCO3 waters. Mixing processes between these waters and either connate brine and/or deep thermal waters contribute to the formation of isolated high salinity Na-Cl-rich waters. In shallow aquifer, inputs of N-rich sewage and agriculture-related contaminants, and SOx emissions in proximity of the harbor are responsible of the increasing nitrate and sulphate concentrations, respectively. The Cl/Br and NO3/Cl ratios highlight contamination mainly linked to agricultural activities and contribution of wastewater. Along the northern boundary, the warmest groundwater (Na-Cl[SO4]) were found close to a bend of the main strike-slip fault system, locally favouring the rising of B- and Li-rich deep waters, testifying the influence of geological-structural features on deep water circulation. Despite the high-water demand, a direct marine intrusion is localized in a very restricted area, where we observed an incipient groundwater-seawater mixing (seawater contribution ≤7 %). The qualitative and quantitative conditions of the shallow aquifer still have acceptable levels because of the relatively high recharge inflow. A reliable hydrogeochemical conceptual model, able to explain the compositional variability of the studied waters, is proposed.

Description: Published

Description: 160694

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: This study aims to understand the relationship between the palaeoenvironmental evolution of the southern margin of the Salpi lagoon (Tavoliere coastal plain, Apulia, Italy) and the development of settlements on its shores during the last part of the Holocene (Late Northgrippian to Late Meghalayan) to complement recent archaeological investigations at the site of pre-Roman Salpia Vetus, Roman Salapia and Medieval Salpi. Micropalaeontological, palynological, and sedimentological analyses were conducted on a total of ten drilled cores, revealing local and regional events. Facies and micropalaeontological analyses show that the lagoon was partially connected to the sea between 6.2 ka BP and 3.1 ka BP. Between 3.1 ka BP and 2.4 ka BP, the area was characterised by marshes and swamps with restricted brackish lagoon conditions and permanent freshwater input. After 2.4 ka BP, the continuous freshwater influx from the major rivers of the coastal plain determined the progradation of the floodplain and the closure of the lagoon, with the formation of the two coastal lakes of Lago Salso (north) and Lago Salpi (south). Pollen data show the expansion of halophytic herbs under local brackish conditions during the Early Meghalayan and the continuous spread of dryland herbs consistent with the closure of the basin. The alluvial plain progradation during the Late Meghalayan allowed the intensive exploitation of the area and the development of a highly anthropogenic landscape. The development of the settlements of pre-Roman Salpia Vetus, Roman Salapia, and Medieval Salpi was mainly determined by the insalubrious condition of the surrounding marshes, due to the reduction in water depth and oscillations in salinity.

Description: Published

Description: 37-54

Description: 5A. Ricerche polari e paleoclima

Description: JCR Journal

Description: Caldeiras da Ribeira Grande is one of the degassing areas of Fogo, a trachytic central volcano located at Sa ̃o Miguel Island (Azores archipelago). Recently, new steam emissions, soil CO2 and temperature anomalies developed towards the inhabited area, causing high indoor CO2 values and affecting the vegetation and several small animals that were found dead in depressions and low-ventilated zones. During July–August 2021, a soil CO2 flux survey was carried out on the north flank of the volcano, estimating a soil gas release of at least 40 t d− 1 (excluding the contribution of the fumaroles) over an area of ~0.27 km2. Two populations for the CO2 released were found, highlighting the biogenic and volcanic-hydrothermal origins. General NW-SE diffuse degassing structures (DDS) were identified, in agreement with the tectonic lineaments previously recognized in the area. In this regard, we investigated the passive gas dispersion in the atmosphere at Caldeiras da Ribeira Grande per- forming a model validation aimed to estimate the fumarolic gas flux at source and the potential hazard for human and animal lives posed by CO2. Numerical simulations were carried out with the DISGAS-2.3, a 3D Eulerian advection-diffusion model, and the relative outputs processed through the VIGIL-1.3 workflow able to provide probabilistic long-term CO2 concentration maps, considering a meteorological variability over the last 30 years (1991–2020) taken from the ECMWF ERA5 reanalysis dataset. A best-fit between observed and simulated CO2 concentrations allowed us to estimate the total gas flux of the area (~209 t d− 1) obtained by scaling the soil CO2 gas flux by a factor 30. Such an estimate is composed of ~174 t d− 1 as unknown fumarolic and ~ 35 td− 1 as diffuse contribution, in a good agreement with measurements. Although the present-day CO2 concentration at 0.3 m height cannot be considered to raise serious concerns for human health, we reasonably infer that the death of small animals may be due to local conditions of CO2 accumulation or to the presence of H2S. The current study highlights the relevance of coupling gas flux maps, concentration data, and gas dispersion modeling to obtain robust estimation of gas fluxes, including the fuma- rolic contribution, and identify zones potentially impacted by dangerous concentrations of volcanic gases, which are relevant for land-use planning and hazard assessment in case of renewed escalations of volcanic activity.

Description: Published

Description: 107807

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: The ability to image the underground structures of volcanoes is limited by the precision, resolution and pene tration depth of each single geophysical method. In order to improve the knowledge of specific volcanic edifices and to better understand the general behavior of structures, the use of a combination of methods is strongly recommended to exploit and maximize their complementary capabilities of resolution and penetration depths. In this work a large dataset of seismic and electromagnetic measurements has been used to provide a more detailed and improved geophysical image of the shallower portion of the northern sector of Ischia Island(Campania region, Italy), severely hit by the August 21, 2017 earthquake (Mw 3.9). We analysed data by using different methodologies: Horizontal-to-Vertical Spectral Ratio (HVSR), seismic array technique (f k),polarization analysis and Time Domain ElectroMagnetic (TDEM) survey. These methods are sensitive in a different way to tectonic features, lithologies, layer geometry and fluid distribution. Thus, their combination is useful for studying sites with complex crustal structures such as Ischia island, which is characterized by a well-developed geothermal system linked to the presence of a shallow magmatic body. Results of our study provides detailed information of the physical properties of the subsoil through: 1) the spatial distribution of the amplification parameters of ground motion, showing frequency peaks below 1 Hz and/or between 1 Hz and 5 Hz; 2) the definition of the velocity models up to 600 m depth, with shear wave velocities ranging from 150 m/s for the shallower layers to 2500 m/s for the half space; 3) the recognition of the correlation between the principal fault structures and polarization directions of the noise wavefield, mostly oriented along EW and NE-SW directions; 4) the resistivity models of the first 80 m depth with high resistivity values of the shallow layers in the range 50–100 Ω.m and low resistivity values of the bottom layers in the range 1–10 Ω.m.

Description: Published

Description: 107820

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: Sea-level rise is one of the most significant and perceptible consequences of global warming because it affects natural environments and coastal anthroposcapes at human timescales, particularly in sediment-starved littoral contexts. Within this framework, improvements in understanding the projection of sea-level rise require better knowledge of regional changes. Here we focus on the recent sea-level history of the Mediterranean Sea, an area characterized by a densely populated coast and where climate variability is larger, and the rate of sea-level rise higher than the global average. We produce a spatially-averaged Mediterranean relative sea-level (RSL) time series, based on 138 tide-gauge records, stretching back to the late 1800s, indicating that Mediterranean RSL has risen by ∼24 cm in the past ∼140 years. At interdecadal timescales and beyond, we find that Mediterranean relative sea-level rising rates (RSLRR) are significantly influenced by the strength of the Atlantic Multidecadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC). Climate-model predictions of a weakened Atlantic overturning circulation in the coming decades, slowing and diminishing North Atlantic heat transport, has the potential to accentuate Mediterranean rising rates, with significant implications for the basin's coastal societies, infrastructure and economies. We conservatively estimate that a 0.1 °C decrease in AMO sea surface temperatures can accentuate Mediterranean RSLRR by up to −0.61 ± 0.5 mm yr−1. Future coastal management and adaptation policies must assimilate these findings into local/regional-scale impact and vulnerability assessments.

Description: Published

Description: 104456

Description: 4A. Oceanografia e clima

Description: JCR Journal

Description: Tidal forces are generally neglected in the discussion about the mechanisms driving plate tectonics despite a worldwide geodynamic asymmetry also observed at subduction and rift zones. The tidal drag could theoretically explain the westerly shift of the lithosphere relative to the underlying mantle. Notwithstanding, viscosity in the asthenosphere is apparently too high to allow mechanical decoupling produced by tidal forces. Here, we propose a model for global scale geodynamics accompanied by numer- ical simulations of the tidal interaction of the Earth with the Moon and the Sun. We provide for the first time a theoretical proof that the tidal drag can produce a westerly motion of the lithosphere, also com- patible with the slowing of the Earth’s rotational spin. Our results suggest a westerly rotation of the litho- sphere with a lower bound of x % ð0:1 0:2Þ /Myr in the presence of a basal effective shear viscosity g % 1016 Pa s, but it may rise to x 〉 1 /Myr with a viscosity of g K 3 1014 Pa s within the Low- Velocity Zone (LVZ) atop the asthenosphere. This faster velocity would be more compatible with the mainstream of plate motion and the global asymmetry at plate boundaries. Based on these computations, we suggest that the super-adiabatic asthenosphere, being vigorously convecting, may further reduce the viscous coupling within the LVZ. Therefore, the combination of solid Earth tides, ultra-low viscosity LVZ and asthenospheric polarized small-scale convection may mechanically satisfy the large-scale decoupling of the lithosphere relative to the underlying mantle. Relative plate motions are explained because of lat- eral viscosity heterogeneities at the base of the lithosphere, which determine variable lithosphere- asthenosphere decoupling and plate interactions, hence plate tectonics.

Description: Published

Description: 101623

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: The WSW-ENE Meran-Mauls Fault (MMF) represents a break in the broadly E-W trending Periadriatic Fault (PAF), separating the Southern Alps from the N-verging wedge of the European Alps. Understanding the MMF evolution is mandatory to reconstruct the role of the entire PAF during the evolution of the belt since the late Cenozoic. Structural and microstructural analyses and paleostress calculations based on fault-slip data suggest the occurrence of four evolutionary stages for the MMF: 1) top-to-the-SE mylonites; 2) top-to-the-SE brittle faulting; 3) dextral faulting with re-activation of previous structures; 4) N–S compression associated with conjugate sets of mainly strike-slip fault systems. Paleostress reconstructions point to a σ2-σ3 permutation from stage 2 to stage 3, resulting in the switch from pure thrusting to strike-slip, followed by an anticlockwise rotation of the principal stress axes during stage 4, in a strike-slip regime related to N–S compression. Geochronological and thermochronological data point to 39-22 Ma age for stage 1, 22-17 Ma for stage 2, less than 17 Ma for stage 3. Our reconstruction strongly supports the interpretation of the MMF as a restraining bend of the PAF, which was weakly reactivated along its eastern portion as a dextral fault and later displaced by NNE-SSW left-lateral faults.

Description: Published

Description: 104878

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: In the brittle regime, faults tend to be oriented along an angle of about 30° relative to the principal stress direction. This empirical Andersonian observation is usually explained by the orientation of the stress tensor and the slope of the yield envelope defined by the Mohr-Coulomb criterion, often called critical-stress theory, assuming frictional properties of the crustal rocks (μ ≈ 0.6−0.8). However, why the slope has a given value? We suggest that the slope dip is constrained by the occurrence of the largest shear stress gradient along that inclination. High homogeneous shear stress, i.e., without gradients, may generate aseismic creep as for example in flat decollements, both along thrusts and low-angle normal faults, whereas along ramps larger shear stress gradients determine higher energy accumulation and stick-slip behaviour with larger sudden seismic energy release. Further variability of the angle is due to variations of the internal friction and of the Poisson ratio, being related to different lithologies, anisotropies and pre-existing fractures and faults. Misaligned faults are justified to occur due to the local weaknesses in the crustal volume; however, having lower stress gradients along dip than the optimally-oriented ones, they have higher probability of being associated with lower seismogenic potential or even aseismic behavior.

Description: Published

Description: 100211

Description: 2T. Deformazione crostale attiva

Description: N/A or not JCR

Description: The AD 472 eruption of Somma-Vesuvius widely impacted the northern and eastern territory around the volcano, laying down a complex sequence of pyroclastic fallout and pyroclastic current deposits. During archaeological test excavations conducted in the Acerra locality, Pollena eruption (AD 472) fallout and lahar deposits composed of fine ash containing traces of plant impressions were found. These deposits were sampled and carefully frac tured in order to recover the plant imprints. Features of the ash impressions were compared with those of live plants and dried Herbarium specimens. Species identification was based on the characteristics of leaves (maximum width, type of leaf margin, size of midrib, angle of formation of the secondary veins) and fruits. Impressions of Mandragora officinarum L., Rosa canina L. and Hedera helix L. were recognized. This is the first documented discovery of subfossil mandrake specimens. The use of mandrake plants for healing and psycho tropic purposes is referred to by Classical authors such as Pliny the Elder and Dioscorides; it was sometimes used mixed with rose. In addition, rose and ivy plants were symbolically important to the ancient Romans and were employed together as medicinal plants. The coexistence of these plants in a restricted area suggests the presence of a garden dedicated to sacred/medicinal plants. In addition, it is interesting to note that the discovery of mandrake plants with fruits supports the hypothesis that the eruptive event took place between the end of summer and the autumn.

Description: Published

Description: 103802

Description: 5V. Processi eruttivi e post-eruttivi

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal