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Study of the variations of the feeding system at Mt. Etna during the paroxysmal activities by using infrasonic data
No full textThe maim objective of this work is to investigate the structure of the superficial portion of the plumbing system at Mt. Etna in terms of interconnection among the conduits and internal variations linked to eruptive activity. For this purpose, the lava fountains that occurred in the years from 2011 to 2015 were taken into consideration, for a total of 51 events, and the infrasonic signals recorded by two stations were analysed. We extracted the infrasonic events, and analysed the evolution in time of the spectral content by using normalized and non-normalized pseudospectrograms, peak and mean frequency values. In addition, the sources of the events were located. We noted how, although the eruptions took place at South-East and Voragine craters, the infrasonic events recorded before and after the lava fountains are mostly generated by the North-East Crater. Most of the energy of these events is comprised in the frequency range 0.1 – 2 Hz. Furthermore, in most of the lava fountain episodes, we observed a decrease in the frequency peaks of the infrasonic events after the eruptions. To interpret the variations of the plumbing system responsible for these spectral changes, as well as the interconnection among the conduits feeding the main craters, we model the infrasonic events from the North-East Crater as an acoustic resonance of the crater and conduit, whose length changes with time as magma ascends or descends in the conduit.PublishedVienn
The 3D Crustal Structure in the Epicentral Region of the 1980, Mw 6.9, Southern Apennines Earthquake (Southern Italy): New Constraints From the Integration of Seismic Exploration Data, Deep Wells, and Local Earthquake Tomography
No full textWe present the first 3D crustal model of the epicentral region of the 1980, Mw 6.9, normal-faulting Irpinia earthquake (southern Italy) determined by jointly interpreting the CROP-04 deep seismic profile, a grid of commercial seismic lines, deep exploration wells, and a high-resolution Local Earthquake Tomography. Despite numerous seismotectonic surveys and source studies of the background seismicity recorded by dense networks, a complete 3D geological model of the mid-upper crust was still lacking in the region. The architecture of the Neogene fold-and-thrust belt is also debated, with competing thin- and thick-skinned tectonic interpretations. We use the 3D geological model derived from subsurface exploration data to interpret the upper crustal tomographic velocities in terms of rock physical properties, while Vp and Vp/Vs anomalies provide inferences on the deep structural setting down to 12 km depth. We find that a thick-skinned deformation style allows explaining the geometry of Pliocene fold-and-thrust systems deforming the Apulian carbonates but also deeper Permo-Triassic metasediments and the Paleozoic crystalline femic basement. Inherited compressional structures and lithological heterogeneities control background seismicity occurring at two crustal levels. Fluid-driven shallow seismicity (<4–6 km) concentrates in a high-Vp/Vs wedge of fractured, brine-saturated Mesozoic stiff rocks delimited by the 1980 earthquake faults. Deep seismicity (9–14 km) clusters instead within the low-Vp/Vs crystalline basement underneath the Apulian carbonate ramp-anticlines. Commercial seismic data allow us to identify the Irpinia Fault, the main fault ruptured by the 1980 earthquake, reinforcing its previous interpretations as an immature structure with subtle geological and geophysical evidence.Publishede2023TC008056OST1 Alla ricerca dei Motori GeodinamiciJCR Journa
CO2 budget from a 3D chemical tomography of a degassing volcanic lake (Lagoa das Furnas, São Miguel, Azores)
No full textWe here present a 3D mapping of the dissolved CO2 at Lagoa das Furnas (S˜ao Miguel Island, Azores) obtained with an infrared-based probe that measures the partial pressure of CO₂ gas dissolved in liquids, and a multiparametric probe to measure pH, ORP, conductivity, dissolved O2, and temperature. We interpolated the dissolved CO2 at different depths and around the lake to calculate the total mass of CO2 dissolved as CO2 (aq) (109–176 tons). We identified different plumes of dissolved CO2 that spatially correspond to previously detected shallow anomalies of the diffusive CO2 degassing at the water-air (interface) and hydroacoustic signatures of the bubbling activity. Our result represents the first direct quantification of the total dissolved CO2 in a volcanic lake, opening new perspectives for volcanic lake monitoring and related hazard assessment.Published108012OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
About the “predecessors” of the 2023 February earthquakes, Turkey
No full textIn the frame of a comprehensive investigation of historical earthquakes of Anatolia, we propose a re-appraisal of four major earthquakes/sequences occurred after 1000 AD (1114/1115, 1269, 1513/1514 and 1544), which could be considered as predecessors of the earthquakes of February 6, 2023. The main purpose is to provide reliable parameter values for the investigated earthquakes. Our investigation consisted of: retrieving and analysing the main primary historical sources; identifying the localities mentioned and assessing macroseismic intensity; determining earthquake parameters (location, magnitude and – where possible – the source azimuth) with the repeatable and transparent “Boxer” method, after properly calibrating the relevant coefficient by considering recent earthquakes of the Anatolian region. Our investigations show that the 1114 earthquake can be considered as a predecessor of the main 2023 earthquake, although the latter ruptured a larger area; the earthquake of 1544 may be a predecessor of the second event of 2023, February; and that the background of the 1513/1514 earthquake is so poor that a lot of care is required while handling the currently available parameters. In conclusion, we also compare our results with the findings of paleoseismological investigation and discuss how they contribute to understanding the rupture history of the East Anatolian Fault.PublishedN/A or not JC
A new perspective in radon risk assessment: Mapping the geological hazard as a first step to define the collective radon risk exposure
No full textRadon is a radioactive gas and a major source of ionizing radiation exposure for humans. Consequently, it can pose serious health threats when it accumulates in confined environments. In Europe, recent legislation has been adopted to address radon exposure in dwellings; this law establishes national reference levels and guidelines for defining Radon Priority Areas (RPAs). This study focuses on mapping the Geogenic Radon Potential (GRP) as a foundation for identifying RPAs and, consequently, assessing radon risk in indoor environments. Here, GRP is proposed as a hazard indicator, indicating the potential for radon to enter buildings from geological sources. Various approaches, including multivariate geospatial analysis and the application of artificial intelligence algorithms, have been utilised to generate continuous spatial maps of GRP based on point measurements. In this study, we employed a robust multivariate machine learning algorithm (Random Forest) to create the GRP map of the central sector of the Pusteria Valley, incorporating other variables from census tracts such as land use as a vulnerability factor, and population as an exposure factor to create the risk map. The Pusteria Valley in northern Italy was chosen as the pilot site due to its well-known geological, structural, and geochemical features. The results indicate that high Rn risk areas are associated with high GRP values, as well as residential areas and high population density. Starting with the GRP map (e.g., Rn hazard), a new geological-based definition of the RPAs is proposed as fundamental tool for mapping Collective Radon Risk Areas in line with the main objective of European regulations, which is to differentiate them from Individual Risk Areas.Published169569OSA5: Energia e georisorseJCR Journa
Hydrothermal alteration and physical and mechanical properties of rocks in a volcanic environment: A review
No full textVolcanic rocks are the prominent host rocks in geothermal and volcanic systems in general, displaying heterogeneity. Although various external factors such as temperature, pressure, time, fluid chemistry, and subsurface geology have been thoroughly researched regarding the source of hydrothermal minerals in geothermal fields, the effect of hydrothermal alteration on volcanic hosts is still controversial in the literature. This review compiles data on the physical and mechanical properties of the host rocks composing volcanic environments exhibiting hydrothermal alteration or remaining unaltered. The considered data is originated from hydrothermal areas from Kuril-Kamchatka (Russia), Los Humeros (Mexico), Ngatamaraki, Rotokawa, Kawerau and Ohakuri geothermal fields and Mt. Ruapehu, Mt. Taranaki, and Whakaari volcanoes (New Zealand), Solfatara (Italy), Reykjanes, Nesjavellir, and Theistarereykir geothermal fields (Iceland), La Soufrière de Guadeloupe (Caribbean) volcano, and Merapi volcano (Indonesia).
Analysis of average values displayed in several graphical representations and correlations finds that dense rocks (such as lavas and intrusive rocks) exhibit greater competence and lower porosity than fragmental rocks. However, altered dense rocks display greater variability in mechanical properties compared to pyroclastic rocks, primarily influenced by mineral dissolution leading to rock weakening. Exceptions occur for high-temperature hydrothermal alteration, such as advanced silicification and propylitic alteration, with the latter influenced by minor types of alteration. Fragmental rocks have diverse behaviour with the extent of hydrothermal alteration and welding/compaction. According to the compiled data, an overall strengthening of pyroclastic rocks develops as hydrothermal alteration increases, regardless of the type of hydrothermal alteration.
The complexity of hydrothermal systems, the variability shown by different hydrothermal settings and histories in terms of temperature, fluid chemistry and secondary mineral assemblage, and the variety of rock materials with different microstructures contribute to moderate correlations between properties compared to those established in an unaltered state. However, the same trends (linear, nonlinear, positive, negative) are preserved along hydrothermal alteration. This review emphasizes the significance of the type and degree of hydrothermal alteration, along with the rock type and pre-existence of fractures, in shaping the development of alteration in volcanic environments and modifying the properties of host rocks. The relevance of the review relies on the fact that these properties are considered to enhance the productivity of geothermal fields and improve the assessment of volcanic hazards. Future research is expected to expand on this groundwork.Published104754OSV4: Preparazione alle crisi vulcanicheJCR Journa
Scaling Properties of Magnetic Field Fluctuations in the High-Latitude Ionosphere
No full textSpace plasma turbulence plays a relevant role in several plasma environments, such as solar
wind and the Earth’s magnetosphere–ionosphere system, and is essential for describing their complex
coupling. This interaction gives rise to various phenomena, including ionospheric irregularities and
the amplification of magnetospheric and ionospheric currents. The structure and dynamics of these
currents have relevant implications, for example, in studying ionospheric heating and the nature
of electric and magnetic field fluctuations in the auroral and polar environments. In this study, we
investigate the nature of small-scale fluctuations characterizing the ionospheric magnetic field in
response to different geomagnetic conditions. We use high-resolution (50 Hz) magnetic data from the
ESA’s Swarm mission, collected during a series of high-latitude crossings, to probe the scaling features
of magnetic field fluctuations in auroral and polar cap regions at spatial scales still poorly explored.
Our findings reveal that magnetic field fluctuations in field-aligned currents (FACs) and polar cap
regions across both hemispheres are characterized by different scaling properties, suggesting a
distinct driver of turbulence. Furthermore, we find that geomagnetic activity significantly influences
the nature of energy dissipation in FAC regions, leading to more localized filamentary structures
toward smaller scales.Published1928OSA3: Climatologia e meteorologia spazialeJCR Journa
PAPER VOLCANOES LAB: ENGAGING YOUNG CHILDREN WITH EARTH SCIENCE IN KENYA. WHAT WE HAVE ACCOMPLISHED SO FAR
No full textAlthough most of East Africa’s volcanoes are currently dormant they could erupt in the future, while 25%
of Africa’s volcanoes had eruptions in the last 100 years. How to be prepared and respond to natural
hazards such as volcanoes, need to be communicated to young children, learning settings and
communities. The project presented here has been funded by IUGG and supported by IAVCEI within
the priority area Geoscience Education and Outreach in Developing Countries. It aims to present the
Paper Volcanoes toolkit and create a dialogue between science and the indigenous knowledge to
communicate natural hazards to children considering their identity and context. The Paper Volcanoes
Laboratory toolkit is an experience based activity enriched with pedagogical elements, created within
the INGV Educational Group, to help early childhood children to familiarize themselves with natural
hazards including volcanoes.
The project focuses on the Turkana rural setting in Kenya where the regional volcanism is known by
geologists or indigenous people through their traditional stories. Here we present the methodology used,
the preparatory pilot involving four universities students and Turkana early childhood teachers to
experience the Paper volcano toolkit and the extended pilot. The pilot was run in September 2022 in
Lodwar and consisted of four themed workshops involving stakeholders, teachers (40) and elders. The
pilot enabled teachers to hear the stories about the Turkana mountains, experience the paper toolkit, to
share ideas, to connect with geoscience specialists and sociologists.PublishedValenciaOS: Terza mission
The micro‐seismicity of Co. Donegal (Ireland): Defining baseline seismicity in a region of slow lithospheric deformation
No full textA catalogue of precisely located micro-seismicity is fundamental for investigating seismicity and rock physical properties in active tectonic and volcanic regions and for the definition of a ‘baseline’ seismicity, required for a safe future exploitation of georesource areas. In this study, we produce the first manually revised catalogue of micro-seismicity for Co. Donegal region (Ireland), an area of about 50K M2 of on-going deformation, aimed at localizing natural micro-seismic events occurred between 2012 and 2015. We develop a stochastic method based on a Markov chain Monte Carlo (McMC) sampling approach to compute earthquake hypocentral location parameters. Our results indicates that micro-seismicity is present with magnitudes lower than 2 (the highest magnitude is 2.8).The recorded seismicity is almost clustered along previously mapped NE-SW trending, steeply dipping faults and confined within the upper crust (focal depth less than 10 km). We also recorded anthropogenic seismicity mostly related to quarries' activity in the study area.Published62-76OST1 Alla ricerca dei Motori GeodinamiciJCR Journa
Evaluating the incompleteness magnitude using an unbiased estimate of the b value
No full textThe evaluation of the b value of the Gutenberg–Richter (GR) law, for a sample composed of n
earthquakes, presents a systematic positive bias δb which is proportional to 1/n . In this study,
we show how to incorporate in δb the bias introduced by deviations from the GR law. More
precisely we show that δb is proportional to the square of the variability coefficient CV, defined
as the ratio between the standard deviation of the magnitude distribution and its mean value.
When the magnitude distribution follows the GR law CV = 1 and this allows us to introduce a
new graphical procedure, based on the dependence of b on n, which allows us to identify the
incompleteness magnitude mc as the threshold magnitude leading to CV = 1. The method is
tested on synthetic catalogues and it is applied to estimate mc in Southern California, Japan
and New Zealand.Published994-1001JCR Journa