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Iole Serena Diliberto - One of the best experts on this subject based on the ideXlab platform.
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long term monitoring on a closed conduit volcano a 25 year long time series of temperatures recorded at la fossa cone vulcano island italy ranging from 250 c to 520 c
Journal of Volcanology and Geothermal Research, 2017Co-Authors: Iole Serena DilibertoAbstract:Abstract The longest record of temperature data from an active volcano in southern Italy is presented. The dataset comes from continuous monitoring of Fumarole temperatures from the La Fossa cone of Vulcano (Aeolian Islands) running from 1991 to 2016. The discussion includes an empirical approach, based on a large number of direct measurements. At Vulcano Island, geochemical monitoring of the uprising fluids allows detection of the surface effects of perturbation in the state variables of the buried hydrothermal and magmatic systems. The presented datasets show that Fumaroles' changing temperatures, which are related to surface heat flow, are useful indicators. Over the past 25 years, the combined effects of runoff and chemo-physical alterations were negligible on the output temperature of the earliest monitored Fumaroles. The maximum recorded variation was 298 °C (measured in the ground very close to the steaming vents, at a depth of 0.5 m). Repetition of output temperature values occurred after 19 years in the same position; the time variations suggest a cyclic characteristic, although more years are needed to register the complete cyclic modulation. A combination of minor cyclical variations has also been registered in the Fumarole output. The minor cycles appeared in this long series of data after 1995, and they can be interpreted as one of the surface effects of temporary departures from a stationary state assumed for the system feeding the La Fossa area. In this sector of the Mediterranean area, the steady state pressure field, as well as the steady state temperature gradients, can be perturbed either by magmatism or by seismo-tectonic processes related to regional dynamics. This long-term monitoring allowed comparisons of many temperature subsets with other validated geochemical and geophysical data series and highlighted common source mechanisms accounting for endogenous processes. Changes in the magma source and/or seismo-tectonic activity have been the primary causes of the time variations. The collected data show the effectiveness of the geochemical approach for following the heat flow changes that originated from a deep source in real time, even though an estimation of magmatic and/or hydrothermal energy release cannot be retrieved by surface temperature monitoring alone.
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time series analysis of high temperature Fumaroles monitored on the island of vulcano aeolian archipelago italy
Journal of Volcanology and Geothermal Research, 2013Co-Authors: Iole Serena DilibertoAbstract:Abstract The exhalation activity at the La Fossa cone (Vulcano Island, Aeolian Archipelago, Italy) has been ongoing for more than 1 century. Many of the monitored geochemical and geophysical parameters have showed transient variations of energy release. The time-series analyses of Fumarole temperatures presented in this paper enabled the sequence of observations to be defined and information from different monitoring stations to be integrated. The motion of fluids feeding the Fumaroles of the La Fossa cone is driven by the thermal and kinetic energies that balance the seismic and volcanic forces active in the region, and the temperatures of the Fumaroles reflect the local response of the hydrothermal system to these forces. During a 14-year period of observation, from 1998 to 2012, Fumarole temperatures showed various trends but also cyclic variations characterized by sharp increases. The repetition of these variations during periods with different trends indicates that no physical variation occurred from the hydrothermal source to the surface during the analyzed period, and after each periodic geochemical crisis the previous thermal conditions were restored. Although the continuous monitoring of high-temperature Fumaroles was limited to only a few sites, the observed trends characterized the most important Fumaroles in the area of Vulcano Island. An evaluation of thermal-energy release based on these spatially discrete measurements would be a speculative exercise in thermodynamics, but the analyses of the recorded data represent a step forward in interpreting the signals from ongoing volcanic activity and in assessing the seismic risk.
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continuous monitoring of Fumarole temperatures at mount etna italy
Journal of Volcanology and Geothermal Research, 2013Co-Authors: Paolo Madonia, Iole Serena Diliberto, Andrea Luca Rizzo, Rocco FavaraAbstract:Abstract In this paper we present the first data of temperature continuously recorded in two Fumarole fields (designated VOR and HOR) located in the summit area of Mount Etna volcano (Italy). The time series embraces two distinct periods: (1) October 2007 to November 2009, during which an effusive eruption occurred from May 2008 to July 2009, and (2) November 2011 to June 2012, characterized by the occurrence of strong paroxysms (fire fountains and lava flow). The analysis of the temperature signal in both the time and frequency domains, and its comparison with meteorological observations allowed us to separate the exogenous influences from the effects of variations in the activity state of the volcano. The acquired data were weakly affected by seasonal cycles of the air temperature and strongly affected by the rainfall. Optimization of site conditions (i.e., sensor depth and soil permeability) markedly reduced meteorological disturbances. The distance from the main degassing and/or eruptive fractures was crucial to maximizing the probability of the technical survival of the monitoring apparatus, which was seriously affected by the emission of acidic gases, tephra fallout, and lava flows. Apart from the exogenous influences, the most appreciable variation was observed at VOR, where a huge increase in Fumarole temperature was detected immediately after the onset of the 2008–2009 eruption. Such an anomalous increase was attributed to the rapid ascent of magma feeding the eruptive fracture. Another abrupt increase in temperature was recorded at HOR in March and April 2012. During this period the frequency of paroxysm occurrence increased markedly, and this led us to hypothesize that the thermal anomaly was due to the intrusion of a new batch of magma in the conduits of the southeast crater. Medium- to long-term monitoring (weeks to months) of Fumarole temperatures revealed variations that were attributed to pressurization/depressurization phases of the shallow volcanic system, which varied between the various monitored sectors of the volcano. Our observations suggest that continuous monitoring of Fumarole temperature can give useful information about the activity of Mount Etna. Moreover, due to the complexity of its shallow plumbing system, we conclude that the monitoring systems should be extended to cover the entire Fumarole network of the summit area.
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thermal anomalies in Fumaroles at vulcano island italy and their relationship with seismic activity
Physics and Chemistry of The Earth, 2013Co-Authors: Paolo Madonia, Iole Serena Diliberto, P Cusano, Marianna CangemiAbstract:Abstract Fumarole thermal monitoring is a useful tool in the evaluation of volcanic activity, since temperatures strongly relate to the upward flux of magmatic volatiles. Once depurated from meteorological noise, their variations can reflect permeability changes due to crustal stress dynamics eventually associated to seismic activity. In this work, we discuss a Fumarole temperature record acquired in the period September 2009–May 2012 at Vulcano island (Italy), during which changes of volcanic state, local seismic activity and teleseisms occurred. Apart from positive thermal anomalies driven by increments in volcanic activity, we observed 3 episodes at least of concurrence between tectonic earthquakes and Fumarole temperature increments, with particular reference to the local August 16th, 2010 Lipari earthquake, the March 11th, 2011 Sendai–Honshu (Japan) earthquake and a seismic swarm occurred along the Tindari-Letojanni fault in July–August 2011. We interpreted the seismic-related anomalies as “crustal fluid transients”, i.e. signals of volcanogenic vapour flow variations induced by stress-induced permeability changes. From this perspective fumarolic activity can be considered as a tracer of geodynamic instability but, since seismic and volcanic phenomena are in mutual cause-effect relationships, a multidisciplinary observation system is mandatory for correctly addressing thermal data interpretation.
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long term variations of Fumarole temperatures on vulcano island italy
Annals of Geophysics, 2011Co-Authors: Iole Serena DilibertoAbstract:Fumarole temperatures are the ultimate results of many processes that are encountered by deep fluids during their passage to the surface. Here, the time variations of high-temperature Fumaroles acquired by continuous monitoring are presented, to show the effects of the forces that act on the system. Data acquired by continuous monitoring of Fumaroles and the time relationships with the different parameters related to the activity of the volcanic system are discussed. From 1998 to 2010, the temperature and compositional changes of fumarolic gases were monitored at the same time as variations in the number of volcanoseismic events, which indicate frequent variations of energy release (heat and mass flow, and seismic strain release). Geochemical modeling applied to the volcanic system of Vulcano Island suggests that the overall expansion of magmatic gas through the fractured system is an almost iso-enthalpic process at depth, which shifts to an adiabatic process at shallow depth, where the rock permeability increases. Thus, the time variations of the Fumarole temperatures reflect various physical variations of the system that can either occur at depth or close to the surface. The temperature monitoring performed in the fumarolic area of La Fossa Cone showed short-term effects related to rain events, and negligible effects related to other external agents (ambient temperature and atmospheric pressure variations). At the same time, the long-term monitoring highlighted some mean-term and long-term variations. These last are the main characters observed in the time-series, and they both appear to be related to endogenous forces that perturb the equilibrium of this complex geochemical system.
Thomas Lebourg - One of the best experts on this subject based on the ideXlab platform.
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Three-Dimensional Electrical Resistivity Tomography of the Solfatara Crater (Italy): Implication for the Multiphase Flow Structure of the Shallow Hydrothermal System
Journal of Geophysical Research : Solid Earth, 2017Co-Authors: Marceau Gresse, Giovanni Chiodini, S. Byrdina, Timothy Johnson, Tullio Ricci, Giuseppe Vilardo, Annarita Mangiacapra, Jean Vandemeulebrouck, André Revil, Thomas LebourgAbstract:The Solfatara volcano is the main degassing area of the Campi Flegrei caldera, characterized by 60 years of unrest. Assessing such renewal activity is a challenging task because hydrothermal interactions with magmatic gases remain poorly understood. In this study, we decipher the complex structure of the shallow Solfatara hydrothermal system by performing the first 3‐D, high‐resolution, electrical resistivity tomography of the volcano. The 3‐D resistivity model was obtained from the inversion of 43,432 resistance measurements performed on an area of ~0.68 km2. The proposed interpretation of the multiphase hydrothermal structures is based on the resistivity model, a high‐resolution infrared surface temperature image, and 1,136 soil CO2 flux measurements. In addition, we realized 27 soil cation exchange capacity and pH measurements demonstrating a negligible contribution of surface conductivity to the shallow bulk electrical conductivity. Hence, we show that the resistivity changes are mainly controlled by fluid content and temperature. The high‐resolution tomograms identify for the first time the structure of the gas‐dominated reservoir at 60 m depth that feeds the Bocca Grande Fumarole through a ~10 m thick channel. In addition, the resistivity model reveals a channel‐like conductive structure where the liquid produced by steam condensation around the main Fumaroles flows down to the Fangaia area within a buried fault. The model delineates the emplacement of the main geological structures: Mount Olibano, Solfatara cryptodome, and tephra deposits. It also reveals the anatomy of the hydrothermal system, especially two liquid‐dominated plumes, the Fangaia mud pool and the Pisciarelli Fumarole, respectively.
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three dimensional electrical resistivity tomography of the solfatara crater italy implication for the multiphase flow structure of the shallow hydrothermal system
Journal of Geophysical Research, 2017Co-Authors: Marceau Gresse, Giovanni Chiodini, S. Byrdina, Tullio Ricci, Giuseppe Vilardo, Annarita Mangiacapra, Jean Vandemeulebrouck, André Revil, Timothy C Johnson, Thomas LebourgAbstract:The Solfatara volcano is the main degassing area of the Campi Flegrei caldera, characterized by 60 years of unrest. Assessing such renewal activity is a challenging task because hydrothermal interactions with magmatic gases remain poorly understood. In this study, we decipher the complex structure of the shallow Solfatara hydrothermal system by performing the first 3-D, high-resolution, Electrical Resistivity Tomography (ERT) of the volcano. The 3-D resistivity model was obtained from the inversion of 43,432 resistance measurements performed on an area of 0.68 km2. The proposed interpretation of the multiphase hydrothermal structures is based on the resistivity model, a high-resolution infrared surface temperature image, and 1,136 soil CO2 flux measurements. In addition, we realized 27 soil Cation Exchange Capacity (CEC) and pH measurements demonstrating a negligible contribution of surface conductivity to the shallow bulk electrical conductivity. Hence, we show that the resistivity changes are mainly controlled by fluid content and temperature. The high-resolution tomograms identify for the first time the structure of the gas-dominated reservoir at 50 m depth that feeds the Bocca Grande Fumarole through a ~10-m-thick channel. In addition, the resistivity model reveals a channel-like conductive structure where the liquid produced by steam condensation around the main Fumaroles flows down to the Fangaia area within a buried fault. The model delineates the emplacement of the main geological structures: Mt Olibano, Solfatara crypto-dome, and tephra deposits. It also reveals the anatomy of the hydrothermal system, especially two liquid-dominated plumes, the Fangaia mud pool and the Pisciarelli Fumarole, respectively.
Antonio Paonita - One of the best experts on this subject based on the ideXlab platform.
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geochemistry and isotope composition sr pb δ 66 zn of vulcano Fumaroles aeolian islands italy
Chemical Geology, 2018Co-Authors: Massimo Chiaradia, Alessandro Aiuppa, Nuria Pujolsola, Julia Farredepablo, Antonio Paonita, Andrea Luca Rizzo, L BruscaAbstract:Abstract We present and discuss temperatures, major and trace element gas geochemistry, radiogenic isotopes (Pb, Sr) and the first Zn isotope data of Fumarole condensates and altered rocks from the Vulcano fumarolic field. The Fumaroles of the La Fossa cone, sampled on 5th May 2015, have temperatures ranging between 233 and 427 °C. They plot compositionally on the mixing trend between the magmatic and hydrothermal end-members defined by previous studies, but are strongly displaced towards the hydrothermal component. Correlations of radiogenic (Sr, Pb) and stable isotopes of Zn with δ 13 C CO2 and several trace elements of the fumarolic acid condensates support mixing between the above mentioned distinct (magmatic and hydrothermal) fluids. The magmatic end-member has a less radiogenic Sr ( 87 Sr/ 86 Sr ~0.7045) and heavier Zn isotope composition (δ 66 Zn ~0.3‰). The hydrothermal fluid end-member has a more radiogenic 87 Sr/ 86 Sr signature (>0.7055), which could be due to leaching of radiogenic Sr from the crystalline basement rocks or reflect seawater Sr. It is also characterized by lighter Zn isotope composition (δ 66 Zn Pb isotope compositions of the Fumaroles sampled in this study show a shift towards less radiogenic values compared to pre-2001 Fumaroles. This could indicate either a change in the hydrothermal circulation pattern (leading to leaching of rocks with different isotopic compositions) or the involvement of a new, isotopically distinct, magmatic fluid. The alteration zones around the Fumarole vents are also characterized by systematic correlations of Pb and Zn isotopes with major and trace elements. We interpret these as the result of the addition onto the substratum volcanic rock of Pb and Zn from the Fumaroles. Zn isotope signatures of the alteration zones are significantly heavier than those of the corresponding Fumaroles (δ 66 Zn = 0.3–1.6) probably due to equilibrium fractionation occurring during sphalerite precipitation at the vent discharge.
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the episodic and abrupt geochemical changes at la fossa Fumaroles vulcano island italy and related constraints on the dynamics structure and compositions of the magmatic system
Geochimica et Cosmochimica Acta, 2013Co-Authors: Antonio Paonita, G. Pecoraino, Cinzia Federico, P Bonfanti, Giorgio Capasso, S Inguaggiato, F Italiano, Paolo Madonia, F SortinoAbstract:Abstract Herein we report on the chemical and isotopic (C, H, O, and He) compositions of the fluids from La Fossa crater Fumaroles of Vulcano from 1999 to 2010. Consistent with records obtained since the end of the 1980s, our data show that the geochemical features of the Fumarole system have experienced several episodes of remarkable change, each lasting no more than a few months. Typical signatures of these short-term anomalies are large increments in CO 2 , N 2 , and He concentrations, coupled to increased 13 C/ 12 C isotopic ratios, but their meaning remains widely debated. Within a model of fumarolic fluids based on mixing between hydrothermal and magmatic endmembers, we have developed a novel approach to constrain chemical (He/CO 2 and N 2 /He) and isotopic ( 13 C/ 12 C, D/H, and 3 He/ 4 He) ratios of the magmatic endmember during the short-term anomalies. Although much of the geochemical variability in Fumaroles results from changes in mixing proportions, the magmatic fluid unquestionably shows significant variations in time. The magmatic He/CO 2 , N 2 /He, 13 C/ 12 C, and 3 He/ 4 He values throughout 1988–1996 differed from those feeding the anomaly at the end of 2004. Early clues of the new magmatic fluid appeared in 1998–1999, far from any short-term anomaly, whereas new and old magmatic fluids coexisted after 2004. We quantitatively prove that the detected geochemical changes are consistent with the degassing path of a magma having a latitic composition, and suggest the presence of two magma ponding levels at slightly different pressures, where bubble–melt decoupling can occur. The different He-isotope compositions at these levels suggest low hydraulic connectivity typical of a complex reservoir with dike and sill structures. In this framework, the short-term geochemical anomalies are probably due to gas accumulation at the top of magma bodies followed by massive escape, or activation of new degassing levels in the reservoir, for which the stress field almost certainly plays a key role. Such a scenario explains the observed increases in both Fumarole output and shallow high-frequency seismicity (due to increased pore pressure) during the anomalies, while being consistent with the concomitant absence of any deep seismicity or ground deformation, eventually related to magma movement.
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hydrothermal processes governing the geochemistry of the crater Fumaroles at mount etna volcano italy
Chemical Geology, 2010Co-Authors: Marcello Liotta, Antonio Paonita, Andrea Luca Rizzo, Antonio Caracausi, M Martelli, R FavaraAbstract:article i nfo We investigated the geochemistry of the Fumaroles at the summit area of Mt. Etna, including sulfur speciation and the content of acidic gases. The carbon-isotope composition of the Etnean plume was also measured in order to compare it to that of Fumaroles. Two types of Fumaroles were identified: (i) low-temperature Fumaroles, which are dominated by CO2 with minor amounts of SO2 and H2S, and negligible chlorine contents, and (ii) high-temperature Fumaroles, which are strongly air-contaminated and characterized by appreciable amounts of volcanogenic carbon, sulfur, and chlorine. As recognized by Martelli et al. (2008), both groups of Fumaroles are fed by the degassing of an underlying magma; nevertheless, compositional data clearly show that secondary processes affect the composition of the fluids once they leave the magma body. Here a model of cooling and condensation of fluids is proposed to explore such postmagmatic processes. The model, which uses Etnean plume geochemistry as starting composition of fluids exsolved from magma, shows that SO2 and H2S control the redox conditions of the gas mixture during the cooling, until the reactions involving CO/CO2 and H2/H2O ratios are fully quenched at temperatures around 350-450 °C. The dissolution of gases in water, subsequent to condensation, must occur at thermobaric conditions over 50 bar and 260 °C, which allows (a) total removal of HCl, (b) partial removal of sulfur species while preserving the SO2/H2S ratio, and (c) the C/S ratio to increase by almost 10-fold relative to that in the plume. The observed CH4/CO2 ratios are higher than those calculated for the Etnean magmatic gas, and hence they provide evidence of modest contributions from peripheral hydrothermal fluids during the migration of magmatic gases toward the surface in both low- and high-temperature Fumaroles. Due to the peculiar thermodynamic conditions, the model predicts that carbon isotopes do not experience any postmagmatic fractionation, and hence the isotopic composition of the Fumaroles is representative of magmatic carbon. Measurements of the carbon-isotope composition of the plume corroborate these findings.
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genesis of chlorine and sulphur in fumarolic emissions at vulcano island italy assessment of ph and redox conditions in the hydrothermal system
Journal of Volcanology and Geothermal Research, 2002Co-Authors: V Di Liberto, P M Nuccio, Antonio PaonitaAbstract:Chlorine- and sulphur-bearing compounds in Fumarole discharges of the La Fossa crater at Vulcano Island (Italy) can be modelled by a mixing process between magmatic gases and vapour from a boiling hydrothermal system. This allows estimating the compounds in both endmembers. Magma degassing cannot explain the time variation of sulphur and HCl concentrations in the deep endmember, which are more probably linked to reactions of solid phases at depth, before mixing with the hydrothermal vapours. Based on the P–T conditions and speciation of the boiling hydrothermal system below La Fossa, the HCl and Stot contents in the hydrothermal vapours were used to compute the redox conditions and pH of the aqueous solution. The results suggest that the haematite–magnetite buffer controls the hydrothermal fO2 values, while the pH has increased since the end of the 1970s. The main processes affecting pH values may be linked to Na–Ca exchanges between evolved seawater, feeding the boiling hydrothermal system, and local rocks. While Na is removed from water, calcium enters the solution, undergoes hydrolysis and produces HCl, lowering the pH of the water. The increasing water–rock ratio within the hydrothermal system lowers the Ca availability, so the aqueous solution becomes less acidic. Seawater flowing towards the boiling hydrothermal brine dissolves a large quantity of pyrite along its path. In the boiling hydrothermal system, dissolved sulphur precipitates as pyrite and anhydrite, and becomes partitioned in vapour phase as H2S and SO2. These results are in agreement with the paragenesis of hydrothermal alteration minerals recovered in drilled wells at Vulcano and are also in agreement with the isotopic composition of sulphur emitted by the crater Fumaroles.
Thomas R Walter - One of the best experts on this subject based on the ideXlab platform.
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surveying Fumarole sites and hydrothermal alteration by unoccupied aircraft systems uas at the la fossa cone vulcano island italy
Journal of Volcanology and Geothermal Research, 2021Co-Authors: Daniel Muller, Stefan Bredemeyer, Edgar U Zorn, Erica De Paolo, Thomas R WalterAbstract:Abstract Degassing volcanic systems, expressed by Fumaroles, thermal anomalies, and hydrothermal alteration and deposition at the surface provide insights into the underlying structural architecture and the magmatic system. While the Fumarole sites are easily identified and investigated, areas of diffuse degassing and associated hydrothermal alteration are barely explored. Here we investigate high-resolution optical and thermal infrared (TIR) data, acquired by unoccupied aircraft systems (UAS) at the La Fossa cone (Vulcano Island) in November 2018. The data provides insights into the structural complexity of degassing sites and associated processes at the surface. Applying the Structure from Motion (SfM) approach, we generate a photomosaic database with a 0.05 m and 0.7 m pixel resolution for the optical and infrared datasets, respectively. A Principal Component Analysis (PCA) was applied to the optical data to detect, define and extract areas of hydrothermal alteration and sulfuric deposition on a pixel base, with a feature detection threshold of up to 25 cm2. By comparing optical data, PCA results and the IR data, we found a broad alteration zone dominated by diffuse degassing surrounding the main Fumaroles, which with ~ 60,000 m2 is ten times larger than the area covered by Fumaroles and yellowish sulfuric deposits. Spectral and thermal characteristics of this alteration zone suggest a segmentation into at least 13 distinct subregions. Hydrothermal alteration and deposition were analyzed considering their pixel density and spectral signature (RGB) and show the highest pixel density in the center of the Fumarole field, accompanied by a systematic color shift. The same region is characterized by a systematic change in azimuths of thermal lineaments and sulfuric clusters from the dominating trend NW-SE by ~90 degrees to NE-SW. We conjecture this to be controlled by a permeability contrast due to a subsurface structure or crater intersection, facilitating a more direct gas ascent in the center of the Fumarole field. We provide a precise and complete database for the state and extent of the La Fossa Fumarole field, which can be used for comparative monitoring of spatio-temporal changes within the hydrothermal system at the surface.
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thermal and gas dynamic investigations at lastarria volcano northern chile the influence of precipitation and atmospheric pressure on the Fumarole temperature and the gas velocity
Journal of Volcanology and Geothermal Research, 2017Co-Authors: Martin Zimmer, Thomas R Walter, Christian Kujawa, Ayleen Gaete, Luis FrancomarinAbstract:Abstract Fumaroles are hydrothermal manifestations commonly associated with active volcanoes. The dynamics of Fumaroles are affected by interactions with internal and external factors, however, hazardous access and corrosive gases have so far limited successful case studies. In this study we report and discuss the results of continuous thermal monitoring carried out on three high temperature (> 250 °C) Fumaroles at the Lastarria volcano Chile, together with simultaneously measured meteorological parameters from December 2013 to March 2016. In addition, the dynamic pressure and the CO2 concentration were recorded in a fourth vent. The investigated sites are located in the largest and most dominant Fumarole field which developed in a fracture system on the north-west flank of the volcanic edifice. We detect external factors controlling the Fumarole temperature and the dynamic gas pressure, for a better understanding of changes in these parameters and, consequently, to improve the evaluation of volcanic and hydrothermal activity. Selected Fumaroles showed a continuous decrease in temperature, or remained unbiased from this trend showing that the influence of external effects on outlet temperature is strongly site dependent. But generally, significant decreases in all vent temperatures can be observed in response to intensive precipitation. Diurnal variations occur only in the coolest fourth Fumarole, where gas temperature, gas pressure and CO2 concentration are inversely correlated with atmospheric pressure. Small barometric pressure reductions account for an increase in mass flow subsequently resulting in a higher temperature and CO2 concentration. The temperatures and thermodynamic properties of the fumarolic gas and infiltrated precipitation water were used to calculate the amount of discharging gas from the investigated field with about 67 × 106 m3 per day which is equivalent to 3545 tons.
Marceau Gresse - One of the best experts on this subject based on the ideXlab platform.
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Three-Dimensional Electrical Resistivity Tomography of the Solfatara Crater (Italy): Implication for the Multiphase Flow Structure of the Shallow Hydrothermal System
Journal of Geophysical Research : Solid Earth, 2017Co-Authors: Marceau Gresse, Giovanni Chiodini, S. Byrdina, Timothy Johnson, Tullio Ricci, Giuseppe Vilardo, Annarita Mangiacapra, Jean Vandemeulebrouck, André Revil, Thomas LebourgAbstract:The Solfatara volcano is the main degassing area of the Campi Flegrei caldera, characterized by 60 years of unrest. Assessing such renewal activity is a challenging task because hydrothermal interactions with magmatic gases remain poorly understood. In this study, we decipher the complex structure of the shallow Solfatara hydrothermal system by performing the first 3‐D, high‐resolution, electrical resistivity tomography of the volcano. The 3‐D resistivity model was obtained from the inversion of 43,432 resistance measurements performed on an area of ~0.68 km2. The proposed interpretation of the multiphase hydrothermal structures is based on the resistivity model, a high‐resolution infrared surface temperature image, and 1,136 soil CO2 flux measurements. In addition, we realized 27 soil cation exchange capacity and pH measurements demonstrating a negligible contribution of surface conductivity to the shallow bulk electrical conductivity. Hence, we show that the resistivity changes are mainly controlled by fluid content and temperature. The high‐resolution tomograms identify for the first time the structure of the gas‐dominated reservoir at 60 m depth that feeds the Bocca Grande Fumarole through a ~10 m thick channel. In addition, the resistivity model reveals a channel‐like conductive structure where the liquid produced by steam condensation around the main Fumaroles flows down to the Fangaia area within a buried fault. The model delineates the emplacement of the main geological structures: Mount Olibano, Solfatara cryptodome, and tephra deposits. It also reveals the anatomy of the hydrothermal system, especially two liquid‐dominated plumes, the Fangaia mud pool and the Pisciarelli Fumarole, respectively.
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three dimensional electrical resistivity tomography of the solfatara crater italy implication for the multiphase flow structure of the shallow hydrothermal system
Journal of Geophysical Research, 2017Co-Authors: Marceau Gresse, Giovanni Chiodini, S. Byrdina, Tullio Ricci, Giuseppe Vilardo, Annarita Mangiacapra, Jean Vandemeulebrouck, André Revil, Timothy C Johnson, Thomas LebourgAbstract:The Solfatara volcano is the main degassing area of the Campi Flegrei caldera, characterized by 60 years of unrest. Assessing such renewal activity is a challenging task because hydrothermal interactions with magmatic gases remain poorly understood. In this study, we decipher the complex structure of the shallow Solfatara hydrothermal system by performing the first 3-D, high-resolution, Electrical Resistivity Tomography (ERT) of the volcano. The 3-D resistivity model was obtained from the inversion of 43,432 resistance measurements performed on an area of 0.68 km2. The proposed interpretation of the multiphase hydrothermal structures is based on the resistivity model, a high-resolution infrared surface temperature image, and 1,136 soil CO2 flux measurements. In addition, we realized 27 soil Cation Exchange Capacity (CEC) and pH measurements demonstrating a negligible contribution of surface conductivity to the shallow bulk electrical conductivity. Hence, we show that the resistivity changes are mainly controlled by fluid content and temperature. The high-resolution tomograms identify for the first time the structure of the gas-dominated reservoir at 50 m depth that feeds the Bocca Grande Fumarole through a ~10-m-thick channel. In addition, the resistivity model reveals a channel-like conductive structure where the liquid produced by steam condensation around the main Fumaroles flows down to the Fangaia area within a buried fault. The model delineates the emplacement of the main geological structures: Mt Olibano, Solfatara crypto-dome, and tephra deposits. It also reveals the anatomy of the hydrothermal system, especially two liquid-dominated plumes, the Fangaia mud pool and the Pisciarelli Fumarole, respectively.
