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Favara, Rocco
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Favara, Rocco
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rocco.favara@ingv.it
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- PublicationRestrictedMethane emission from the mud volcanoes of Sicily (Italy)(2002)
; ; ; ; ; ;Etiope, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Caracausi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Baciu, C.; Babes-Bolyai University, Department of Geology, Cluj-Napoca, Romania; ; ; ; Mud volcanoes represent the largest expression of natural methane release into the atmosphere; however, the gas flux has never been investigated in detail. Methane output from vents and diffuse soil degassing is herewith reported for the first time. Measurements were carried out at 5 mud volcano fields around Sicily (Italy). Each mud volcano is characterized by tens of vents and bubbling pools. In the quiescent phase, methane emission from single vents ranges between 0.01 and 6.8 kg/day. Diffuse soil leakage around the vents is in the order of 102–104 mg m 2 d 1. An exceptional flux of 106 mg m 2 d 1 was recorded close to an everlasting fire. Soil CH4 flux is positive even at large distances from the mud volcano fields suggesting a diffuse microseepage over wider areas. A total of at least 400 tons CH4 per year can be estimated over the area investigated alone ( 1.5 km2).697 180 - PublicationOpen AccessHydrogeochemical characterization of the alluvial aquifer of Catania Plain, Sicily (South Italy)(2023)
; ; ; ; ; ; ; ; ; ; ; A hydrogeochemical study was carried out on the shallow Catania Plain alluvial aquifer, in eastern Sicily to reconstruct its hydrogeological structure, the meteoric recharge and to assess the infuence of human activities on groundwater. To characterize the geochemistry of the shallow aquifer, two sampling campaigns were carried out, August–October 2004 and April–May 2005 in 47 sites distributed throughout the plain. The samples were collected and analyzed for physical–chemical parameters and major ions, as well as stable isotopes (δ18O and δ2 H). Alluvial deposits with heterogeneous grain sizes constitute the aquifer. Varying conditions of vertical and horizontal permeability lead to the presence of a multilayered aquifer with diferent conditions of confnement and partial interconnection among layers. The sampled waters were separated into four groups of diferent compositions due to the water–rock interaction with the diferent lithologies present in and around the study area. Maps of electrical conductivity and sulfate show a systematic control of land use, in correspondence with the biggest farms. High sulfate concentration is due to both the natural interaction between local meteoric waters and Etna’s plume and the mixing with groundwater coming from the area where evaporitic rocks of the Gessoso Solffera formation are present. In addition, anthropogenic contamination cannot be ruled out. A rain gauge network, consisting of 3 sites located at diferent altitudes, was installed to collect rain waters to determine isotopic data (δ2 H and δ18O) and to measure the monthly rainfall amount. Based on the isotopic composition of sampled waters, it has been established that beyond the direct meteoric recharge, the recharging areas are in the North (Mt. Etna) and the South (Hyblean Plateau).148 11 - PublicationRestrictedGenesis of fumarolic emissions as inferred by isotope mass balances: CO2 and water at Vulcano Island, Italy(2002)
; ; ; ; ;Paonita, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Nuccio, P. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Sortino, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; ; ; We have developed a quantitative model of CO2 and H2O isotopic mixing between magmatic and hydrothermal gases for the fumarolic emissions of the La Fossa crater (Vulcano Island, Italy). On the basis of isotope balance equations, the model takes into account the isotope equilibrium between H2O and CO2 and extends the recent model of chemical and energy two-end-member mixing by Nuccio et al. (1999). As a result,the H2O and CO2 content and the dD, d18O, and d13C isotope compositions for both magmatic and hydrothermal end-members have been assessed. Low contributions of meteoric steam, added at a shallow depth, have been also recognized and quantified in the fumaroles throughout the period from 1988 to 1998. Nonequilibrium oxygen isotope exchange also seems to be occurring between ascending gases and wall rocks along some fumarolic conduits. The d13CCO2 of the magmatic gases varies around -3 to 1‰ vs. Peedee belemnite (PDB), following a perfect synchronism with the variations of the CO2 concentration in the magmatic gases. This suggests a process of isotope fractionation because of vapor exsolution caused by magma depressurization. The hydrogen isotopes in the magmatic gases (-1 to -35‰ vs. standard mean ocean water [SMOW]), as well as the above d13CCO2 value, are coherent with a convergent tectonic setting of magma generation, where the local mantle is widely contaminated by fluids released from the subducted slab. Magma contamination in the crust probably amplifies this effect. The computed isotope composition of carbon and hydrogen in the hydrothermal vapors has been used to calculate the dD and d13C of the entire hydrothermal system, including mixed H2O-CO2 vapor, liquid water, and dissolved carbon. We have computed values of about 10‰ vs. SMOW for water and -2 to -6.5‰ vs. PDB for CO2. On these grounds, we think that Mediterranean marine water (dDH2O 10‰) feeds the hydrothermal system. It infiltrates at depth throughout the local rocks, reaching oxygen isotope equilibrium at high temperatures. Interaction processes between magmatic gases and the evolving seawater also seem to occur, causing the dissolution of isotopically fractionated aqueous CO2 and providing the source for hydrothermal carbon. These results have important implications concerning fluid circulation beneath Vulcano and address the more convenient routine of geochemical surveillance.372 88 - PublicationOpen AccessGeophysical Constraints to Reconstructing the Geometry of a Shallow Groundwater Body in Caronia (Sicily)(2023)
; ; ; ; ; ; ; ; ; ; ; ; ; The characterization of a groundwater body involves the construction of a conceptual model that constitutes the base knowledge for monitoring programs, hydrogeological risk assessment, and correct management of water resources. In particular, a detailed geological and geophysical approach was applied to define the alluvial Caronia Groundwater Body (CGWB) and to reconstruct a hydrogeological flow model. The analysis of the CGWB, located in north-eastern Sicily, was initially approached through a reanalysis of previous stratigraphic (boreholes) and geophysical (vertical electrical soundings and seismic refraction profiles) data, subsequently integrated by new seismic acquisitions, such as Multichannel Analysis of Surface Waves (MASW) and horizontalto- vertical seismic ratio (HVSR). The analysis and reinterpretation of geoelectrical data allowed the construction of a preliminary 3D resistivity model. This initial modeling was subsequently integrated by a geophysical data campaign in order to define the depth of the bottom of the shallow CGWB and the thickness of alluvial deposits. Finally, a preliminary mathematical model flow was generated in order to reconstruct the dynamics of underground water. The results show that integration of multidisciplinary data represent an indispensable tool for the characterization of complex physical systems.39 6 - PublicationOpen AccessThermal anomalies and fluid geochemistry framework in occurrence of the 2000-2001 Nizza Monferrate seismic sequence (northern Italy): Episodic changes in the fault zone heat flow or chemical mixing phenomena?(2003)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; The paper discusses the correlation between the heating of shallow groundwater over a 10 × 20 km wide area close to the town of Nizza Monferrato (Piemonte Region, Northern Italy) and the concomitant local seismic sequences during the period August 2000 – July 2001. The first seismic sequence started on 21 August 2000 with a Ml = 5.2 earthquake. Within few hours, the local authorities received calls alerting that the groundwater temperature rose from 10 to 30°C in many shallow wells. Our geochemical experimental data and the geological-seismotectonic framework do not allow the hypothesis of simple fluid mixing between the thermal reservoir of Acqui Terme and the Nizza-Monferrato shallow groundwater to explain the observed thermal anomalies. On the other hand, we invoke more complex processes such as frictional heating, mechano-chemistry, fault-valve mechanism, adiabatic decompression and hydrogeologically driven heat flow i.e., thermal effects due to variations of basin-scale permeability field. All these processes are able to transmit heat to the surface and to generate a transient incremental heat flow better than the mass transfer occurring typically when fluids from different reservoirs mix105 27 - PublicationRestrictedEvaluation of carbon isotope fractionation of soil CO2 under an advective–diffusive regimen: A tool for computing the isotopic composition of unfractionated deep source(2007-06-15)
; ; ; ; ;Camarda, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;De Gregorio, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Gurrieri, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; ; ; A physical model based on the advective–diffusion theory was developed in order to describe the mixing between a deep gas source and the atmosphere. The model was used to predict the isotopic fractionation of carbon in soil CO2. Gas samples were collected at different depths in areas characterized by different geological settings and CO2 fluxes. The relative theoretical and experimental isotopic profiles were compared and a good agreement was found. These profiles show how the isotopic composition of CO2 changes through the upper few decimeters of soil and how the amount of the isotopic fractionation is strongly influenced by soil CO2 flux. Finally, the model was used to derive the carbon isotopic composition of unfractioned deep CO2 source for all the investigated sites365 40 - PublicationRestrictedGas hazard assessment at the Monticchio Mt. Vulture, a volcano in Southern Italy(2009)
; ; ; ; ; ;Caracausi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Nuccio, P. M.; Dipartimento Chimica e Fisica della Terra e Applicazioni, Universita` di Palermo, Via Archirafi 36, 90100, Palermo, Italy ;Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Nicolosi, M.; Dipartimento Chimica e Fisica della Terra e Applicazioni, Universita` di Palermo, Via Archirafi 36, 90100, Palermo, Italy ;Paternoster, M.; Dipartimento Scienze Geologiche, Universita` della Basilicata, Via dell’Ateneo 10, 85100, Potenza, Italy; ; ; ; Geochemical investigations have shown that there is a considerable inflow of gas into both crater lakes of Monticchio, Southern Italy. These lakes are located in two maars that formed 140 000 years ago during Mt. Vulture volcano s last eruptive activity. Isotopic analyses suggest that CO2 and helium are of magmatic origin; the latter displays 3He ⁄ 4He isotope ratios similar to those measured in olivines of the maar ejecta. In spite of the fact that the amount of dissolved gases in the water is less than that found in Lake Nyos (Cameroon), both the results obtained and the historical reports studied indicate that these crater lakes could be highly hazardous sites, even though they are located in a region currently considered inactive. This could be of special significance in very popular tourist areas such as the Monticchio lakes, which are visited by about 30 000 people throughout the summer, for the most part on Sundays.264 26 - PublicationRestrictedChange in magma supply dynamics identified in observations of soil CO2 emissions in the summit area of Mt. Etna(2014-07-17)
; ; ; ; ;De Gregorio, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Camarda, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Gurrieri, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; ; ; We report the results of 16 months of continuous measurements of soil CO2 flux at a fumarole field in the summit area of Mt. Etna. The patterns of soil CO2 emissions suggest two contrasting degassing regimes. During the period of observation, volcanic activity at the summit craters displayed striking extremes, ranging from passive to explosive degassing, which culminated in lava fountains. These changes in activity coincided with fluctuation between the two degassing patterns. Building on the findings of previous studies, we propose an interpretative framework that explains the observed correlation in terms of a modification of the dynamics of magma supply. We argue that periods of higher CO2 flux are associated with deep open system degassing conditions, whereas low-level CO2 flux signals closed system degassing and less efficient discharge of deeply exsolved gas. An important implication of our study is that, in relation to the two degassing regimes, two types of activity are expected at the summit craters. Thus, our measurements represent a valuable tool for the evaluation of the evolution of volcanic activity571 66 - PublicationOpen AccessCoastal Groundwater Bodies Modelling Using Geophysical Surveys: The Reconstruction of the Geometry of Alluvial Plains in the North-Eastern Sicily (Italy)(2024)
; ; ; ; ; ; ; ; ; The integration of various geophysical methodologies is considered a fundamental tool for accurately reconstructing the extent and shape of a groundwater body and for estimating the physical parameters that characterize it. This is often essential for the management of water resources in areas affected by geological and environmental hazards. This work aims to reconstruct the pattern and extent of two groundwater bodies, located in the coastal sectors of the North-Eastern Sicily, through the integrated analysis and interpretation of several geoelectrical, seismic and geological data. These are the Sant’Agata-Capo D’Orlando (SCGWB) and the Barcelona-Milazzo (BMGWB) Groundwater Bodies, located at the two ends of the northern sector of the Peloritani geological complex. These two studied coastal plains represent densely populated and industrialized areas, in which the quantity and quality of the groundwater bodies are under constant threat. At first, the resistivity models of the two groundwater bodies were realized through the inversion of a dataset of Vertical Electrical Soundings (VES), constrained by stratigraphic well logs data and other geophysical data. The 3D resistivity models obtained by spatially interpolating 1D inverse VES models have allowed for an initial recognition of the distribution of groundwater, as well as a rough geological framework of the subsoil. Subsequently, these models were implemented by integrating results from active and passive seismic data to determine the seismic P and S wave velocities of the main lithotypes. Simultaneous acquisition and interpretation of seismic and electrical tomographies along identical profiles allowed to determine the specific values of seismic velocity, electrical resistivity and chargeability of the alluvial sediments, and to use these values to constrain the HVSR inversion. All this allowed us to recognize the areal extension and thickness of the various lithotypes in the two investigated areas and, finally, to define the depth and the morphology of the base of the groundwater bodies and the thickness of the filling deposits.36 6 - PublicationRestrictedEvoluzione tettonica mesozoico-terziaria della Sicilia centrosettentrionale(2009)
; ; ; ; ;Nigro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Salvaggio, G.; Dipartimento di Geologia e Geodesia, Università di Palermo, Italy - Via Archirafi, 22, 90123, Palermo ;Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Renda, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; ; ; Sicily owes its complex geological structure to a switch in tectonic regime from the Mesozoic to the Tertiary. A set of tectonic units outcrops in the northern portion of the island that originated during the Tertiary at the expense of paleogeographic domains of the African Mesozoic continental margin. The pre-orogenic successions show different types of deformation (extensional and transcurrent) related to the Jurassic paleotectonic evolution of the southern Neotethys margin. The history of the tectonic inversion of the Neotethys shear zone is recorded in the Cretaceous strata. Extension occurred during late Cretaceous and may be compatible with the tensile stress field related to the Sicilide basin opening. The Neogene deformations are linked to collisional processes and are mostly represented by thrusts and folds. Since the late Miocene onwards, the formation of the Tyrrhenian basin has driven the recent tectonic evolution of Northern Sicily. Its basin formation was realised through extension, followed by transcurrent tectonics along its southern margin.314 52