OA Earth-prints Repository
Not a member yet
16457 research outputs found
Sort by
An explainable Machine Learning model for Large-Scale Travelling Ionospheric Disturbances forecasting
No full textLarge-Scale Travelling Ionospheric Disturbances (LSTIDs) are wave-like ionospheric fluctuations, generally triggered by geomagnetic storms, which play a critical role in space weather dynamics. In this work, we present a machine learning model able to forecast the occurrence of LSTIDs over the European continent up to three hours in advance. The model is based on CatBoost, a gradient boosting framework. It is trained on a human-validated LSTID catalogue with the various physical drivers, including ionogram information, geomagnetic, and solar activity indices. There are three forecasting modes depending on the demanded scenarios with varying relative costs of false positives and false negatives. It is crucial to make the model predictions explainable, so that the output contribution of each physical factor input is visualised through the game-theoretic SHapley Additive exPlanation (SHAP) formalism. The validation procedure consists of a global-level evaluation and interpretation step, firstly, followed by an event-level validation against independent detection methods, which highlights the model's predictive robustness and suggests its potential for real-time space weather forecasting. Depending on the operating mode, we report an improvement ranging from +72% to +93% over the performance of a rule-based benchmark. Our study concludes with a comprehensive analysis of future research directions and actions to be taken towards full operability. We discuss probabilistic forecasting approaches from a cost-sensitive learning perspective, along with performance-centric model monitoring. Finally, through the lens of the conformal prediction framework, we further comment on the uncertainty quantification for end-user risk management and mitigation.PublishedJCR Journa
Gas equilibrium in the H 2 O-H 2 -CO 2 -CO-CH 4 system for wet-steam geothermal-well fluids and their sources: A case study from Krafla, Iceland
No full textEquilibrium in the H 2 O-H 2-CO 2-CO-CH 4 gas system has been extensively applied to fumarole data for geothermal exploration and volcano monitoring. However, little is known about its application to two-phase (vapor and liquid) geothermal well fluids, which can show an excess of enthalpy. Here, we applied the H 2 O-H 2-CO 2-CO-CH 4 gas indicators to two-phase geothermal well discharges from the Krafla geothermal system, Iceland, to estimate aquifer temperatures and identify secondary processes during resource exploitation. Results suggest that the Krafla resource is drawn from a deep (approximately between-500 and-1,600 m a.s.l.), two-phase aquifer with temperatures ranging from 272 to 320 • C and vapor fractions between 0.26 and 0.93, explaining the excess enthalpy observed in well fluids. These estimates align with the temperatures of the main production zones of geothermal wells, whereas solute geothermometers (SiO 2 and Na/K) appear to record lower temperatures of minor, shallower, liquid aquifers. Wells with liquid-like enthalpy are sourced from the two-phase aquifer but are also influenced by water reinjection or downflows from a colder, shallower aquifer, consistent with the isothermal zone extending approximately between 400 and-900 m a.s.l. in Leirbotnar and Vesturhlíðar subfields. Water isotopes indicate the main aquifer is recharged by meteoric and reinjection fluids. Excess-enthalpy discharges show an influx of Ar-and N 2-rich vapor, with depleted 40 Ar/ 36 Ar and δ 15 N values, suggesting fractionations of atmospheric gases dissolved into the reservoir liquid. On the other hand, δ 13 C CO2 and 3 He/ 4 He values point to a mantle origin, despite the lower δ 13 C CO2 and P CO2 levels that reflect a degassed magma (i.e., a noneruptive phase). These findings underscore the usefulness of the H 2 O-H 2-CO 2-CO-CH 4 gas system and isotopic methods in tracking geothermal reservoir temperatures, their sources, and secondary processes, such as water reinjection or downflows from shallower aquifers.PublishedOSA5: Energia e georisorseJCR Journa
Impact of cooling rate on rheology and emplacement dynamics of basaltic lavas: Insights from the January 2024 Sundhnúksgígar eruption (Iceland)
No full textThe 2023-2024 eruptions at Sundhnúksgígar in Iceland produced tholeiitic basaltic lavas that traveled at high velocities, affecting vast areas. Under such conditions, disequilibrium crystallization can play a fundamental role in modulating the lava flow dynamics and inundation capacity. To investigate this phenomenon, we carried out a comprehensive rheological characterization of the Sundhnúksgígar basalt, analyzing both the liquid phase and the crystal-bearing suspensions under disequilibrium conditions (cooling rates ranging from 0.1 to 10 • C/min) and near-equilibrium conditions (at fixed temperatures between 1242 and 1180 • C). Our results show that the cooling rate critically influences the extent and timescale of disequilibrium crystallization, thereby shaping the rheological evolution of the melt, leading to distinct deformation response of the crystal-bearing magmatic suspension. Compared to other basalts erupted worldwide, the Sundhnúksgígar melt exhibits two main features: i) an exceptionally low rate of viscosity increase induced by crystallization and ii) the ability to crystallize even at the highest cooling rates applied during the experiments. These characteristics may contribute to enhancing the efficiency of external crust formation, limiting heat loss from the inner portion of the lava flow, which consequently cools more slowly. Thermal insulation effects reduce the rate of viscosity increase during lava emplacement, a key factor in determining lava flow inundation potential. Our findings underscore the critical role of disequilibrium crystallization in governing the rheological evolution and emplacement dynamics of basaltic lavas, offering new insights into lava flow behavior.PublishedJCR Journa
Reflections from the 37th International Geological Congress
No full textThis book explores diverse perspectives and practices in geoethics, offering a comprehensive overview of how ethical considerations are being integrated into the geosciences across disciplines and regions. It draws from the session “Geoethics at the Heart of All Geoscience: Serving the Public Good” held at the 37th International Geological Congress (IGC) in Busan, Republic of Korea.
At the core of the discussion is geoethics - an integrated ethical framework for the geosciences. It provides geoscientists with guidance for responsible action in the face of complex global and societal challenges. By embracing their individual and collective responsibilities, geoscientists can play a key role in advancing human well-being and promoting the public good, while reshaping humanity’s relationship with the Earth system.
Contributors to this volume share insights and expertise, outline methodologies and strategies, raise critical questions, propose best practices, and present case studies that address the ethical, social, and cultural dimensions of geoscience. This diversity ensures a pluralistic, interdisciplinary approach that fosters dialogue and collaboration.
Chapters are structured to build a coherent narrative, moving from foundational geoethical concepts to a wide range of applications, and culminating in the theme of diplomacy.
Intended for a broad audience - including geoscientists, scholars across disciplines, humanists, social scientists, students, professionals, policymakers, journalists, and engaged citizens - this book invites reflection and action at the intersection of science, ethics, and society.OS: Terza mission
Undervalued CO2 emissions from soil to the atmosphere in seismic areas: A case study in Tangshan, North China
No full textA large quantity of CO2 produced in the Earth’s interior is emitted to the atmosphere via soil diffusion, especially
in active tectonic areas. Due to the lack of extensive in situ measurements, however, estimations of soil CO2
output have been poorly constrained thus far, leading to the perception that soil CO2 seems to be a marginal
source of global carbon emissions. Here, the contribution of soil CO2 to the atmosphere is discussed based on soil
degassing rates measured at 187 sites in the Tangshan seismic area, North China. The measured degassing rates
ranged from 9.04 g m 2d 1 to 230.42 g⋅m 2d 1, with an average of 87.46 g⋅m 2d 1, suggesting that high
degassing rates are common throughout the region. Carbon isotopic results show that the soil CO2 comes mainly
from the deep-seated carbonates and shallow biogenetic processes. Using the threshold value of the data population
(96.20 g⋅m 2d 1), the background and anomalous areas are distinguished. We find that anomalous
degassing areas overlap well with epicenters of earthquakes with magnitudes greater than 5. The total annual
CO2 output in anomalous areas was estimated to be 38 Mt. This extremely high value can be attributed to the
enlarged degassing areas and enhanced CO2 emissions induced by regional active faults and frequent seismic
activities. Our results indicate that the impact of soil CO2 emissions in seismic regions should receive increased
attention.PublishedJCR Journa
Cross-scale turbulence in space plasmas: old concepts, recent findings, and future challenges
No full textPublishedOSA3: Climatologia e meteorologia spazialeJCR Journa
Assessing Climate Change Impacts on the March 2024 Compound Floods and Saharan Dust Outbreak in Europe
No full textPublishedOSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
A Novel Algorithm for the Decomposition of Non-Stationary Multidimensional and Multivariate Signals
No full textThis article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) licensePublishedJCR Journa
Numerical Modeling Integrated With Field Observations and Analytical Data of the 2021 Cumbre Vieja Eruption Improves Understanding of Eruption Dynamics at Mafic Volcanoes
No full textAbrupt transitions in eruptive style are common at mafic volcanoes, possibly leading to styles that potentially damage infrastructures and threaten the surrounding communities. During the 19th September-13th December 2021 Cumbre Vieja eruption (La Palma, Canary Islands), rapid changes in eruptive style were observed, from vigorous lava fountaining to sporadic intense ash columns, alongside continuous lava effusion, providing an ideal case study for investigation of the mechanisms underlying such transitions. We used a 1D steady-state numerical model for magma ascent to study the driving processes behind the eruptive style transitions. The model considers the complex and non-linear interdependence among the major processes occurring during magma ascents, such as temperature and viscosity evolution, non-ideal gas behavior, outgassing, and disequilibria in crystallization and volatile exsolution. Input parameters of the simulations (inlet pressure and temperature, water and CO 2 content, initial phenocrystal content) are constrained by analytical studies and empirical data. Simulation outputs are compared with field observations and analytical data. Results suggest that a change in the degree of coupling between gas and melt might have caused the eruptive style change. We hypothesize that a change in the conduit geometry triggered this shift. One possible explanation could be a shallow branching of the conduit, which leads to variable magma and gas partitioning between ramifications. Another possible cause could be the temporary partial collapse of the conduit walls near the surface, which might have generated an acceleration of magma, reducing volatile outgassing, increasing magmatic strain, and consequently triggering the observed transition to explosive activity. Plain Language Summary During the Cumbre Vieja eruption on La Palma, September-December 2021, rapid changes in the style of explosive volcanic activity were observed, including transitions from powerful lava fountains to sporadic and intense ash emissions. To understand what drives these sudden eruptive style transitions, we used a computer model to simulate the ascent of magma along the volcanic conduit to the surface. Our model took into account various factors like temperature, viscosity, gas behavior, and crystal formation, based on both analytical studies and natural data. Our findings suggest that the observed transitions in eruptive style are the result of how well gas and magma couple as they ascend. We propose that coupling could be triggered by alterations in the volcanic conduit geometry. For instance, if the conduit branches near the surface, it could lead to uneven distribution of magma and gas, resulting in a change of activity. Alternatively, if part of the conduit collapses, reducing the conduit radius, it could suddenly increase magma velocity and cause explosive activity. Understanding these mechanisms is crucial for predicting and mitigating the hazards associated with volcanic eruptions, thereby protecting lives and infrastructure.PublishedOSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Uncovering the traces of unknown earthquakes at Segesta (NW Sicily, Italy): insights from multidisciplinary investigations
No full textThe transformation of Segesta, from the Hellenistic period (sixth century BCE) to the early Middle Ages (fifth-sixth century CE), has been extensively studied by archaeologists and historians. While social and political changes were the main drivers of urban evolution, practices such as abandonment, spoliation, and building transformations increased buildings' structural vulnerability, making them more prone to seismic damage. Although historical sources from the Roman period do not mention any earthquakes affecting Segesta, recent archaeological investigations have revealed collapsed layers in the Agora and Mango Sanctuary, and structural deformations in the Theater and Doric Temple. Furthermore, architectural analysis indicates the use of anti-seismic construction techniques in at least two structures on the site. Through multidisciplinary archaeoseismological investigations, this study aims to: (i) provide evidence of past earthquakes based on recent excavations literature review, and on-site observations; (ii) explain, through local site-effects, the selective collapse observed in the Agora and Mango Sanctuary, as well as the deformations at the Theater and Doric Temple; and (iii) analyze the seismotectonic framework of the potential seismic sources. To achieve these objectives, the study combines architectural damage surveys, stratigraphic analysis, drone-based photogrammetry, and non-invasive geophysical prospection (HVSR and MASW). This integrated approach enables a quantitative reconstruction of the local seismic response and deformation patterns across the site, while supporting a replicable framework for investigating ancient seismicity in similarly complex archaeological landscapes. These findings highlight a previously unrecognized gap in the seismic history of this low tectonic strain rate region, pointing to the occurrence of significant past earthquakes that are absent from historical records and current seismic catalogs-which, for this area, list only the 1968 Belice Valley sequence. Therefore, this study contributes essential input data for refining the seismic hazard and enhances our understanding of the historical seismicity and regional seismic risk.PublishedOST2 Deformazione e Hazard sismico e da maremotoJCR Journa