OA Earth-prints Repository
Not a member yet
16457 research outputs found
Sort by
Radon on Mt. Etna (Italy): a useful tracer of geodynamic processes and a potential health hazard to populations
No full textRadon gas and its radioactive daughters have been extensively studied on Mt. Etna, both in local volcanic rocks and in all types of fluid emissions from the volcano (crater gases, fumaroles, mofettes, soil gases, groundwaters). The first measurements date back to 1976 and were carried out both in local volcanic rocks and in the crater plume. Since then, fifty-four scientific articles have been published. The largest majority of them (more than 50%) correlated radon emissions with volcanic activity and/or magma dynamics inside Mt. Etna. Many others were focused on possible correlations between time variations of in-soil radon and tectonic activity. The concentration of radionuclides in Etna volcanic rocks was measured on several occasions in order to set background values of radon parents and to study the dynamics of Etna magmas. Some articles analyzed the concentrations of radon in Etna groundwaters and their temporal changes in relation to volcanic activity. Only a few studies focused on methodological aspects of radon measurements in the laboratory. Finally, in recent years, geoscientists began to analyze the possible negative effects on human health from high concentrations of indoor radon in houses near active faults. The overall results show that, in most cases, it is possible to understand the endogenous mechanisms that cause changes in soil radon release from rocks and its migration to the surface. Several physical models were produced to explain how those changes were correlated with Etna’s volcanic activity, making them potential precursors, especially in the cases of eruptive paroxysms. More complex is the analysis of radon changes in relation to tectonic activity. Indeed, if measurements of radon in soil is now considered a robust methodology for identifying buried faults, radon time variations are not always clearly correlated with seismic activity. This difficulty is likely due to the complex interplay between tectonic stress, magma migration/eruption and gas release through faults. In any case, the potential high hazard for human health due to high concentrations of indoor radon in houses close to faults seems to be a well-established fact, which requires particular attention both from the scientific community and the public health authorities.Published11760516A. Geochimica per l'ambiente e geologia medicaJCR Journa
The efficacy of high frequency petrological investigation at open-conduit volcanoes: The case of May 11 2019 explosions at southwestern and northeastern craters of Stromboli
No full textPetrological studies of active volcanoes typically focus on eruptive phenomena occurring over long timescales of the order of days to years, aiming at identifying major changes in the physico-chemical state of magma during ascent towards the surface. Exceptionally, we present results from an integrated petrological and statistical approach based on the compilation of ∼5300 major and trace element data for glass and crystals, in combination with volcanological data on eruptive events occurred over timescales of minutes at Stromboli volcano (Sicily). On May 11, 2019, we had the rare opportunity to collect individual fresh fallout ash products from eighteen mostly consecutive explosions, erupted in a 2-h time span and, at the same time, to acquire continuous high frequency (50 Hz) infrared thermal data of the same explosions. Through video analysis, we observe that explosions were more frequent and ash-dominated at the southwestern crater area (SCA, 8–10 events/h) than at the northeastern crater area (NCA, 3–5 events/h), where coarser material was ejected. The statistical analysis of glass and plagioclase compositions reveals differences in the products erupted from the two crater areas. SCA explosions tapped less differentiated magmas (Mg#∼42–46, ∼257–365 LaN, ∼0.7–0.9 Eu/Eu*) in equilibrium with more anorthitic plagioclase cores (An∼72–88), whereas NCA area explosions are more differentiated (Mg#∼40–44, ∼286–387 LaN, ∼0.6–0.8 Eu/Eu*) and in equilibrium with less anorthitic plagioclase cores (An∼68–82). Thermometric calculations based on major and trace element clinopyroxene-plagioclase-melt equilibrium modeling highlight that the SCA explosions were statistically fed by hotter magmas in comparison to NCA explosions. Plagioclase-based diffusion modeling also indicates longer timescales for the dynamic ascent of NCA magmas, leading to preferential groundmass crystallization at the conduit walls and transition from sideromelane to tachylite groundmass textures. The final emerging picture is that in May 2019, concurrent normal eruptions from different crater areas at Stromboli were heralds of compositionally and thermally diverse magmas rising at different rates within the uppermost branched part of the conduit region. High frequency petrological investigations aided by statistical treatment of data have the potential to constrain dynamic conduit processes related to transient, explosive eruptions in persistently active volcanoes, thereby offering new insights on the interplay between magma dynamics, ascent timescales, and eruptive behavior.Published107255OSV1: Verso la previsione dei fenomeni vulcanici pericolosiOSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Autonomous Satellite Wildfire Detection Using Hyperspectral Imagery and Neural Networks: A Case Study on Australian Wildfire
No full textOne of the United Nations (UN) Sustainable Development Goals is climate action (SDG-13), and wildfire is among the catastrophic events that both impact climate change and are aggravated by it. In Australia and other countries, large-scale wildfires have dramatically grown in frequency and size in recent years. These fires threaten the world's forests and urban woods, cause enormous environmental and property damage, and quite often result in fatalities. As a result of their increasing frequency, there is an ongoing debate over how to handle catastrophic wildfires and mitigate their social, economic, and environmental repercussions. Effective prevention, early warning, and response strategies must be well-planned and carefully coordinated to minimise harmful consequences to people and the environment. Rapid advancements in remote sensing technologies such as ground-based, aerial surveillance vehicle-based, and satellite-based systems have been used for efficient wildfire surveillance. This study focuses on the application of space-borne technology for very accurate fire detection under challenging conditions. Due to the significant advances in artificial intelligence (AI) techniques in recent years, numerous studies have previously been conducted to examine how AI might be applied in various situations. As a result of its special physical and operational requirements, spaceflight has emerged as one of the most challenging application fields. This work contains a feasibility study as well as a model and scenario prototype for a satellite AI system. With the intention of swiftly generating alerts and enabling immediate actions, the detection of wildfires has been studied with reference to the Australian events that occurred in December 2019. Convolutional neural networks (CNNs) were developed, trained, and used from the ground up to detect wildfires while also adjusting their complexity to meet onboard implementation requirements for trusted autonomous satellite operations (TASO). The capability of a 1-dimensional convolution neural network (1-DCNN) to classify wildfires is demonstrated in this research and the results are assessed against those reported in the literature. In order to enable autonomous onboard data processing, various hardware accelerators were considered and evaluated for onboard implementation. The trained model was then implemented in the following: Intel Movidius NCS-2 and Nvidia Jetson Nano and Nvidia Jetson TX2. Using the selected onboard hardware , the developed model was then put into practice and analysis was carried out. The results were positive and in favour of using the technology that has been proposed for onboard data processing to enable TASO on future missions. The findings indicate that data processing onboard can be very beneficial in disaster management and climate change mitigation by facilitating the generation of timely alerts for users and by enabling rapid and appropriate responses.Published7207A. Geofisica per il monitoraggio ambientaleJCR Journa
Geochemical evidence for a lithospheric origin of the Comoros Archipelago (Indian Ocean) as revealed by ultramafic mantle xenoliths from La Grille volcano
No full textPetrology and fluid inclusions (FI) geochemistry are increasingly used in tandem to constrain the compositional
features and evolution of the lithospheric mantle. In this study, we combine petrography and mineral chemistry
with analyses of noble gases (He, Ne and Ar) and CO2 in olivine, orthopyroxene- and clinopyroxene-hosted FI, as well as radiogenic isotope (Sr-Nd-Pb) systematics of ultramafic xenoliths collected at La Grille volcano in Grande Comore Island, aiming at better characterizing one of the most enigmatic and controversial portions of the western Indian Ocean lithospheric mantle. Xenoliths have been divided in three groups on the basis of their
textural features: Group 1 (Opx-bearing), Group 2 (Opx-free) and Group 3 (Cumulate). Overall, petrographic
observations and mineral phase compositions indicate that the sampled lithospheric portion experienced variable degrees of melting (from 5% to 35%), recorded by Group 1 most refractory harzburgites and lherzolites, as well as modal metasomatic processes as evidenced by the crystallization of cpx at the expense of opx in Group 1 fertile lherzolites and wehrlite and by Group 2 xenoliths. Crystallization of slightly oversaturated basic silicate melts seems also to have occurred, as shown by Group 3 xenoliths. A positive trend between temperature and ƒO2 is evident, with Group 2 and 3 xenoliths testifying for hotter and more oxidised conditions than Group 1. The variability of the 4He/40Ar* ratio (0.02–0.39) in Group 1, significantly below typical values of a fertile mantle (4He/40Ar* = 1–5), can be explained by the variable degrees of partial melting coupled to metasomatic enrichment that may account for modifying 4He/40Ar*, as also indicated by the mineral composition. He-Ar-CO2 relationships support the presence of a metasomatic CO2-rich process post-dating the melt extraction and the cumulate formation. The air-corrected 3He/4He isotopic ratios (6.30 to 7.36 Ra) are intermediate between the MORB mantle signature (8 ± 1Ra) and the SCLM (6.1 ± 0.9 Ra). The Ne and Ar isotopic signatures (20Ne/22Ne, 21/Ne/22Ne and 40Ar/36Ar) are consistent with mixing between an air-derived component and a MORB-like mantle, supporting the hypothesis for a lithospheric origin of the Comoros magmas, and arguing against any deep mantle plume-related contribution. This is also corroborated by combining Ne with He isotopes, showing that La Grille ultramafic xenoliths are far from the typical plume-type compositions. Sr-Nd-Pb isotope systematics in opx and cpx from La Grille additionally support a MORB-type signature for the lithospheric mantle beneath the area.Published107406OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Spatial and Temporal Analysis of Carbon Dioxide Concentrations over Italy by means of OCO‑2 Satellite Data Series
No full textCarbon dioxide is a greenhouse gas with sink and source related to natural cycles and anthropic activities. OCO‑2 is a NASA carbon dioxide dedicated mission launched in 2014 aimed to measure the CO2 concentrations in the atmosphere by recording sunlight reflected off the Earth and provides, at the state of the art, the highest spatial resolution for mapping CO2 at global scale. In this work, for the first time, we statistically analyse 8 years of OCO‑2 acquisitions over Italian territory, obtaining the main trend and the seasonal behaviour of CO2 over land. After data reprocessing and compensating on temporal frequency of OCO‑2 acquisitions over Italy, a mean of 21 ppm of increment in the period from 2015 to 2022 has been found. In the data time series, we also noticed a significant acceleration in the trend between 2019 and 2020 and a return to average values of the trend after the COVID19 pandemic lockdown. In addition, such trends have been compared with those achieved by the European Centre for Medium Range Weather Forecasts (ECMWF) model. The data time series was also used to perform a spatial analysis of areas characterized by lower/higherc CO2 concentrations to detect sinks/sources in Italy due to the land use. The analysis reveals that the North Italian regions, with more population and industries, are the source of CO2; moreover, the fundamental role of vegetation as a sink of CO2 is confirmed.PublishedPA533OSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
The Influence of Undercooling and Sector Zoning on Clinopyroxene–Melt Equilibrium and Thermobarometry
No full textThermobarometry provides a critical means of assessing locations of magma storage and dynamics in the lead-up to volcanic eruptions and crustal growth. A common approach is to utilise minerals that have compositions sensitive to changes in pressure and/or temperature, such as clinopyroxene, which is ubiquitous in mafic to intermediate magmas. However, clinopyroxene thermobarometry may carry significant uncertainty and require an appropriate equilibrium melt composition. In addition, the degree of magma undercooling (ΔT) affects clinopyroxene composition and zoning, with common sector zoning potentially obfuscating thermobarometry results. Here, we use a set of crystallisation experiments on a primitive trachybasalt from Mt. Etna (Italy) at ΔT = 25–233 °C, P = 400–800 MPa, H2O = 0–4 wt % and fO2 = NNO + 2, with clinopyroxene crystals defined by Al-rich zones (prisms and skeletons) and Al-poor zones (hourglass and overgrowths) to assess common equilibrium models and thermobarometric approaches. Under the studied conditions, our data suggest that the commonly applied Fe–Mg exchange (cpx-meltKdFe–Mg) is insensitive to increasing ΔT and may not be a reliable indicator of equilibrium. The combined use of DiHd (CaMgSi2O6 + CaFeSi2O6) and EnFs (Mg2Si2O6 + Fe2Si2O6) models indicate the attainment of equilibrium in both Al-rich and Al-poor zones for almost all investigated ΔT. In contrast, CaTs (CaAl2SiO6) and CaTi (CaTiAl2O6) models reveal substantial deviations from equilibrium with increasing ΔT, particularly in Al-rich zones. We postulate that this reflects slower diffusion of Al and Ti in the melt compared with Ca and Mg and recommend the concurrent application of these four models to evaluate equilibrium between clinopyroxene and melt, particularly for sector-zoned crystals.
Thermobarometers calibrated with only isothermal–isobaric experiments closely reproduce experimental P–T at low ΔT, equivalent to natural phenocrysts cores and sector-zoned mantles. Models that also consider decompression experiments are most accurate at high ΔT and are therefore suitable for outermost phenocryst rims and groundmass microlites. Recent machine learning approaches reproduce P–T conditions across all ΔT conditions. Applying our experimental constraints to sector-zoned microphenocrysts and groundmass microlites erupted during the 1974 eccentric eruption at Mt. Etna, we highlight that both hourglass and prism sectors are suitable for thermobarometry, given that equilibrium is sufficiently tested for. The combination of DiHd, EnFs, CaTs and CaTi models identifies compositions closest to equilibrium with the bulk melt composition, and results in smaller differences in P–T calculated for hourglass and prism sectors compared with applying only DiHd and EnFs equilibrium models. This provides a framework to assess crystallisation conditions recorded by sector-zoned clinopyroxene crystals in mafic alkaline settings.Publishedegad074OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Is Sea Level Rise a Known Threat? A Discussion Based on an Online Survey
No full textSince the last century, global warming has been triggering sea level rise at an unprecedented
rate. In the worst case climate scenario, sea level could rise by up to 1.1 m above the current level,
causing coastal inundation and cascading effects, thus affecting about one billion people around
the world. Though widespread and threatening, the phenomenon is not well known to citizens
as it is often overshadowed by other effects of global warming. Here, we show the results of an
online survey carried out in 2020–2021 to understand the level of citizens’ knowledge on sea level
rise including causes, effects, exacerbation in response to land subsidence and best practice towards
mitigation and adaptation. The most important result of the survey is that citizens believe that it
is up to governments to take action to cope with the effects of rising sea levels or mitigate the rise
itself. This occurs despite the survey showing that they actually know what individuals can do and
that a failure to act poses a threat to society. Gaps and preconceptions need to be eradicated by
strengthening the collaboration between scientists and schools to improve knowledge, empowering
our society.Published367–379OSA4: Ambiente marino, fascia costiera ed Oceanografia operativaJCR Journa
New age constraints on the MIS 9 – MIS 5.3 marine terraces of the Pontine Plain (central Italy) and implications for global sea levels
No full textNew constraints were set on the age of marine deposits in the Pontine Plain and of the related sea level
indicators on the Tyrrhenian Sea coast of central Italy by twelve new 40Ar/39Ar dates on detrital sanidine
from these deposits. By combining a new geomorphologic analysis and previous morpho-pedostratigraphic
studies with these geochronological constraints we reconstructed the geometry of four
marine terraces and correlated these with the highstands during the marine isotopic stages (MIS) 9.3, 7.5,
5.5 and 5.3.
Results point to a progressive tilting of the terraces, the elevation increasing from the SE to the NW due
to differential tectonic uplift that occurred over the last 300 ka. We identified a MIS 9 sea level at 30 -
25 m asl in the northwestern sector, whereas the MIS 7.5 sea level reached a maximum of 24 m asl in the
NWand descended to 18 m asl in the central sector. Moderate tilting affected the MIS 5.5 sea level, with
an elevation of 12 to 9.5 m asl in between the Anzio and Circeo headlands. Finally, an undeformed MIS
5.3 sea level at ca. 3 m asl is indicated throughout this coastal reach, confirming previous data suggesting
a much higher absolute sea level during this highstand with respect to the d18O-derived predicted level.Published1078662T. Deformazione crostale attivaJCR Journa
Bridges to Global Ethics: Geoethics at the Confluence of Humanities and Sciences
No full textThis book contributes to the current discussion on geoethics and global ethics within the geoscience and humanities communities. It provides new content and insights into developing convergent human actions in response to global anthropogenic changes, based on perspectives that make it possible to combine geoscience knowledge with humanities and social sciences approaches. Selected authors present their reflections, findings and insights regarding the vision of geoethics (ethics of responsibility towards the Earth) as global ethics from philosophical, humanities and social sciences perspectives. In addition, they discuss ethical frameworks from diverse cultural traditions, searching for points of intersection with geoethics.
The goal: for global environmental problems to be managed via multi-perspective approaches that can more effectively accommodate complexity. Combining the strengths of the geosciences, humanities and social sciences can pave the way for a paradigm shift in how human societies develop adaptive, sustainable responses to environmental changes and societal inequalities.Published1TM. Formazion
Mesoproterozoic geomagnetic field strength from Nova Guarita mafic dykes (Amazon Craton)
No full textPalaeointensity data from the Precambrian are key to understanding the timing of the Earth’s Inner Core Nucleation (ICN). Due to the scarcity of data, the ICN timing is still poorly constrained and is thought to have occurred between 2500 to 500 Ma. Numerical dynamo simulation models predict an increase in entropy, a stronger driving force for convection that could affect the field strength and show an anomaly in the palaeointensity record at ICN. We present new estimates of the geomagnetic field intensity (palaeointensity) from the Mid-Mesoproterozoic (1406 ± 1424 Ma) Nova Guarita dyke swarm, in the northern Mato Grosso State (SW Amazon Craton, Brazil). To obtain palaeointensity estimates, we used the non-heating Preisach method, with palaeointensity criteria at the specimen, and site level. Five sites provided accepted palaeointensity results, yielding virtual dipole moment (VDM) estimate of 65 ± 12 ZAm2 at 1416 ± 13 Ma, 53 ± 4 ZAm2 at 1418 ± 3 Ma, 12 ± 2 and 8 ± 2 ZAm2 at 1418 ± 5 Ma, and 71 ± 16 ZAm2 at 1424 ± 16 Ma, thus an average estimate of 43 ± 30 ZAm2 for ~1410 Ma. The estimate is similar to the average VDM data (~50 ZAm2), calculated for the period from 1600 to 1000 Ma. This average represents only a snapshot of the Earth’s magnetic field strength. While the new data are too limited in time to contribute directly to the question of ICN, they nevertheless contribute to constraints useful for assessing numerical simulations of the Mesoproterozoic geodynamo.Published161–182OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioJCR Journa