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Geoethics for the Future: Facing Global Challenges
No full textGeoethics for the Future: Facing Global Challenges offers a set of points of view on highly topical issues in geosciences and beyond, including societal relevance of geosciences, georesources, sustainable development, geoeducation, georisks, data, as well as philosophical, legal, political, scientific considerations about anthropogenic global changes and the Anthropocene, enabling readers to acquire multifaceted knowledge on topics of global relevance in the 21st Century. This book explores topics vital to our historical moment and the future of human societies, through the analyzes by scholars with different disciplinary backgrounds, emphasizing the need for new cultural and scientific frameworks to address global issues. It aims to foster multidisciplinary and transdisciplinary approaches for problem-solving, by integrating diverse knowledge and visions to effectively tackle urgent global challenges.
Serving as a significant milestone in geoethics, this book provides academics, researchers and students with insights into the ethical and societal dimensions of various challenges arising from human impact on the Earth system.PublishedOS: Terza mission
long-lived magma reservoirs in Tyrrhenian crust
No full textThe late Miocene Monte Capanne and Porto Azzurro plutons are investigated by means of coupled U-Pb zircon and 40Ar/39Ar white mica dating to test the occurrence of long-lived magmatic systems in the upper crust. Zircon crystallized for > 1 Myr in both plutonic systems, with supersolidus conditions overlapping for ~220 kyr indicating previously unrecognized co-existence of the two reservoirs. The development of the Porto Azzurro high T-aureole is post-dated by continuous igneous zircon crystallization until ~ 6.0 Ma. By linking crystallization to post-emplacement cooling of late-stage pulses in both western and eastern Elba we constrain long-lived sizeable reservoirs (possibly the same reservoir) in the Tyrrhenian upper crust between ~8 and 6 Ma.Published258-265OST1 Alla ricerca dei Motori GeodinamiciJCR Journa
Temporal monitoring of fumarole composition at Santorini volcano (Greece) highlights a quiescent state after the 2011–2012 unrest
No full textSantorini Island (Greece) is an active volcano which has alternated between dormant and active periods over the last 650,000 years with the latest volcanic unrest occurring in 2011–2012. Here we report a geochemical survey of fumarolic gases collected at Nea Kameni islet located in the center of the caldera over the period 2015–2022 in order to study the activity of the volcano and changes in hydrothermal conditions. This period is marked by the absence of significant geochemical anomalies compared to the unrest of 2011–2012, implying that no new magma upwelling has occurred. This is evident from the low CO2/CH4 ratio and H2 concentration of fumaroles. An increase of the atmospheric contribution in gases after the 2011–2012 unrest suggests a decrease of the deep gas flow and the chemical and C-He-isotope compositions are compatible with a model of Rayleigh fractionation in which CO2 dissolves in water at decreasing temperatures over time. These results are consistent with temperature estimates obtained using the H2/N2 geothermometer, seismic and geodetic evidences. This implies a slowing of the degassing of the hydrothermal/volcanic system and a cooling of the magma injected at shallow depth in 2011–2012. All these conclusions support a quiescent state of the Santorini volcano over the period 2015–2022.Published1366213JCR Journa
Unveiling the Distinct Structure of the Upper Mantle Beneath the Canary and Madeira Hotspots, as Depicted by the 660, 410, and X Discontinuities
No full textThe Canary and Madeira Islands are two distinct hotspots in the Central-East Atlantic that are close to each other. Their volcanism is generally attributed to underlying mantle plumes, but the detailed structure of these plumes is still not well understood. The thermal and compositional structure of the plume introduces complexities in the phase transitions of the mantle, which impact the depth and magnitude of seismic discontinuities. We use 1,268 high-quality receiver functions from stations located at the two hotspots to detect P-to-s converted phases through a common-conversion point stacking approach and conduct a detailed analysis of mantle seismic discontinuities. The results show that both hotspots are characterized by a thin mantle transition zone (MTZ), with sharp 410 and 660 discontinuities at depths of 428–421 km and 647–664 km, beneath the Canaries and Madeira respectively. The results indicate that the Canary plume crosses the MTZ, whereas the Madeira plume mainly influences the upper portion of the MTZ. Furthermore, we find reliable detections of a sharp X discontinuity beneath the Canaries at 287 km. Its presence suggests the accumulation of silica-rich recycled eclogite at these depths. We also use the amplitudes of P410s and PXs to derive velocity jumps at corresponding discontinuities. Based on these measurements, we estimate that the basalt proportion is 60%–80%, with accumulation being more significant in the Canaries than in Madeira. The MTZ thickness, the presence of the X discontinuity, and the high basalt proportion provide compelling evidence for a deep-rooted thermochemical plume beneath the study area.Publishede2023JB028195OST1 Alla ricerca dei Motori GeodinamiciJCR Journa
UAS-based mapping of the July 3, 2019, ballistics density distribution on the W flank of Stromboli with uncertainty quantification
No full textStromboli is a volcanic island in a persistent state of activity, located off the northern coast of Sicily. The paroxysms have been the most powerful explosive phenomena at Stromboli in the last 150 years. These explosions can produce ballistic projectiles that can heavily affect trails and observation sites as well as hit inhabited areas at lower elevations, down to the coast. On July 3, 2019, a paroxysm significantly affected a great portion of the island with ballistic projectiles. In particular, many decimeter and meter-sized spatter bombs hit the W flank of Stromboli, and ignited multiple fires. In May 2022, we conducted an Unmanned Aerial System photogrammetric campaign over a sector of the W flank of Stromboli that was heavily affected by the paroxysm. The largest clasts were still preserved after 3 years, not disturbed by significant mass wasting phenomena or human interference, and they were not yet hidden by the post-fire regrowth of the brush vegetation. In this study, we constrained the main sources of uncertainty affecting the bombs distribution on the ground, by characterizing a percentage of uncertain clasts, testing various density estimators, and by modeling an areal buffer around the mapped clasts. We produced a 0.18 km2 wide 1.6-cm resolution orthomosaic, a 10-cm resolution Digital Surface Model, and 2813 outlines of the mapped ballistics. Spatial distribution of the ground cover and associated uncertainty were analyzed as a function of the distance and of the angular direction from the source.Published48OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàJCR Journa
A new bridge management system based on spatial database and open source GIS
No full textBridge management is a complex and challenging task at global scale. The main purpose of bridge management is to facilitate the identification of bridge deficiencies in order to carefully plan and execute maintenance operations, and ensure the continued safety of traffic. In 2020, the Italian Ministry of Infrastructure issued mandatory guidelines for risk classification and management, safety assessment and monitoring of bridges. These guidelines rely upon bridge inventory, which includes a number of heterogeneous inspection data organized in different files. This paper presents a hardware and software architecture for the automatic entry of all inspection data (e.g. spatial information, sheets and photos) in a relational spatial database and their visualization through a Desktop and Web GIS (Geographic Information System) application. The procedure is summarized in a new Bridge Management System (BMS), whose main novelty is the full control of the georeferenced infrastructures, with the opportunity of improving the status check and management of bridges and their components. The BMS has been developed using data collected during inspection surveys requested by the Consortium of Sicilian Highways on the conditions of the bridges and viaducts belonging to motorways in Sicily (Italy). The developed system overcomes most of the common limitations in existing BMSs, such as the limited capacity of visualizing geospatial data and the reduced supported data formats, providing a valid Decision Support System in evaluating and prioritizing repair and maintenance actions.Published500–513OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioN/A or not JC
Source analysis of low frequency seismicity at Mt. Vesuvius by a hybrid moment tensor inversion
No full textSeismicity at Mt. Vesuvius has been relatively weak in the last decades. While the occurrence of shallow volcanotectonic (VT) events at Mt. Vesuvius is well known, the occurrence of deeper low frequency events (LF) was only
recently recognized. Previous source studies only targeted VT events, which were found to have quite heterogeneous focal mechanisms. In this paper, we perform for the first time the source inversion of LF seismicity at Mt.
Vesuvius, analysing 27 LF events recorded from 2012 to 2021 with the aim to investigate their source processes.
Given the challenges of analysing weak LF earthquakes, we implement a specific moment tensor (MT) inversion
approach that combines the fit of displacement seismograms in the time domain and amplitude spectra in the
frequency domain. The inversion is simultaneously performed for the source depth and moment tensor components in the 2–7 and 2–5 Hz frequency band, assuming either a full or deviatoric MT representation. Source
parameter uncertainties are estimated by using a Bayesian bootstrapping scheme. Our results confirm a larger
depth of LF events compared to VTs and show a strong heterogeneity of the LF seismic sources, which present
various rupture types, different orientations and heterogeneous, whilst poorly resolved, non-double-couple
components. The MT variability is qualitatively confirmed by significant differences among the recorded
waveforms. The heterogeneity of both VT and LF source processes is attributed to complex source processes in a
highly fractured seismogenic volume submitted to a heterogeneous stress fieldPublished108173OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
A comprehensive monitoring approach for a naturally anoxic aquifer beneath a controlled landfill
No full textThe processes leading to high levels of arsenic (As), iron (Fe), and manganese (Mn) in groundwater, in a naturally reducing aquifer at a controlled municipal landfill site, are investigated. The challenge is to distinguish the natural water-rock interaction processes, that allow these substances to dissolve in groundwater, from direct pollution or enhanced dissolution of hydroxides as undesired consequences of the anthropic activities above. Ordinary groundwater monitoring of physical-chemical parameters and inorganic compounds (major and trace elements) was complemented by environmental isotopes of groundwater (tritium, deuterium, oxygen-18 and carbon-13) and dissolved gases (carbon-13 of methane and carbon dioxide and carbon-14 of methane). Pearson/Spearman correlation indices, as well as Principal Component Analysis (PCA), were used to determine the main correlations among variables. The concurrent presence of As, Fe and CH4, as reported in similar anoxic environments, suggests that anaerobic oxidation of methane could drive the reductive dissolution of As-rich Fe(III) (hydro)oxides. Manganese is more sensitive to carbon dioxide, possibly due to a decrease in pH which accelerates leachate tracer in groundwater, may be subject to false positives due to the reuse of water recovered from leachate treatment (which has the same isotopic signature of leachate) within the plants, to comply with the requirements of the circular economy. The integration of the environmental isotope analysis into the traditional monitoring approach can effectively support the comprehension of processes. However, this strategy needs to be complemented by a good conceptual hydrogeological model and expert evaluation to avoid misinterpretations.Published142657JCR Journa
Spatial migration of temporal earthquake clusters driven by the transfer of differential stress between neighbouring fault/shear-zone structures
No full textUncertainty concerning the processes responsible for slip-rate fluctuations associated with temporal clustering of surface faulting earthquakes is a fundamental, unresolved issue in tectonics, because strain-rates accommodated by fault/shear-zone structures are the key to understanding the viscosity structure of the crust and seismic hazard. We constrain the timing and amplitude of slip-rate fluctuations that occurred on three active normal faults in central Italy over a time period of 20–30 kyrs, using in situ 36Cl cosmogenic dating of fault planes. We identify five periods of rapid slip on individual faults lasting a few millennia, separated time periods of up to 10 millennia with low or zero slip-rate. The rapid slip pulses migrated across the strike between the faults in two waves from SW to NE. We replicate this migration with a model where rapid slip induces changes in differential stress that drive changes in strain-rate on viscous shear zones that drive slip-rate variability on overlying brittle faults. Earthquakes increase the differential stress and strain-rate on underlying shear zones, which in turn accumulate strain, re-loading stress onto the overlying brittle fault. This positive feedback produces high strain-rate episodes containing several large magnitude surface faulting earthquakes (earthquake clusters), but also reduce the differential stress on the viscous portions of neighbouring fault/shear-zones slowing the occurrence of large-magnitude surface faulting earthquakes (earthquake anticlusters). Shear-zones on faults experiencing anticlusters continue to accumulate viscous strain at a lowered rate, and eventually this loads the overlying brittle fault to failure, initiating a period of rapid slip through the positive feedback process described above, and inducing lowered strain-rates onto neighbouring fault/shear-zones. We show that these patterns of differential stress change can replicate the measured earthquake clustering implied by the 36Cl data. The stress changes are related to the fault geometry in terms of distance and azimuth from the slipping structure, implying that (a) strain-rate and viscosity fluctuations for studies of continental rheology, and (b) slip-rates for seismic hazard purposes are to an extent predictable given knowledge of the fault system geometry.Published105096OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
Macroseismic intensity attenuation models calibrated in Mw for Italy
No full textThis study aims at developing new macroseismic intensity attenuation models valid for Italy by exploiting the most updated macroseismic dataset and earthquakes catalogue, as well as the information obtained from a critical analysis of the most recent models in the literature. Several different attenuation models have been calibrated as a function of the moment magnitude (Mw) and epicentral distance from 16,260 intensity data points, that are related to 119 earthquakes occurred after 1900. According to trends and residuals analysis, the preferred calibrated intensity attenuation function is a Log-Linear model for epicentral distance (Repi in km) and a linear model for Mw as:
I(MCS) = 1.81 − 2.61LogR − 0.0039R + 1.42Mw
with pseudo hypocentral distance R = √R2 + (9.87)2 ; the estimated standard deviation is
epi
σ=0.75. Also noteworthy is another model for macroseismic intensity attenuation that proved to be as good as the best model and shows higher sensitivity to physical parameters, such as focal depth and magnitude, especially in the epicentral area. Performance of all calibrated models was also checked on an independent set of 15 post-1900 Italian earth- quakes. One of the results of the present work is the opportunity to define earthquake sce- narios (e.g. probabilistic seismic hazard maps) in terms of Macroseismic Intensity and its related standard deviation, avoiding the uncertainties due to the conversion of various ground shaking parameters into intensity values.Published795–843OST2 Deformazione e Hazard sismico e da maremotoJCR Journa