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  • 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring  (46)
  • 04. Solid Earth::04.08. Volcanology::04.08.01. Gases  (18)
  • AGU  (50)
  • Blackwell  (6)
Collection
Years
  • 1
    Publication Date: 2020-11-16
    Description: 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 if 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.
    Description: In press
    Description: 83-87
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Description: open
    Keywords: volcanic gases ; gas hazard ; crater lakes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2021-05-17
    Description: This is the first report in the scientific literature of direct measurement of the terminal settling velocity of volcanic particles during an eruption. Field measurements using a continuous wave X-band disdrometer were carried out at Mt. Etna on 18 and 19 December 2002, when the explosive activity produced a 4 km high volcanic plume. These data allow the estimation of the intensity of the fallout and the measurement of the terminal settling velocities of the volcanic particles in real-time. The main results are: (1) the tested instrument detected coherent falling volcanic particles from 0.2 to 1 mm diameter; (2) measured terminal settling velocities were in agreement with both experimental and theoretical methods; (3) however, the measured velocities were clustered around few discrete values, rather than a range of velocities as would be expected if the particles were falling simultaneously and discretely. This new methodology has many new applications for local hazard mitigation and improved understanding of fallout processes.
    Description: Published
    Description: 1-5
    Description: partially_open
    Keywords: Volcanology: Explosive volcanism ; Volcanology: Remote sensing of volcanoes ; Volcanology: Instruments and techniques ; Volcanology: Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2021-06-16
    Description: In Ecuador, magmatism results from the subduction of the Nazca Plate beneath the North Western part of South America. North of 2.5°S, the Ecuadorian Quaternary volcanic arc is characterized by about 60 volcanoes distributed along three different parallel NNE-striking chains. Many of these volcanoes are potentially active or currently in activity displaying associated geothermal fields. South of this latitude, no active arc is present in Ecuador. Few geochemical studies of the discharged fluids in this region have been attempted, mainly related to geothermal exploration. Nevertheless, a complete study of the fluids of the volcanic arc is lacking. The aim of this work is to present the first systematic geochemical characterization of discharged fluids from the entire Ecuadorian volcanic arc. In order to achieve this objective, 56 samples of thermal and cold waters, as well as 32 dissolved and 27 bubbling gases, were collected from North to South across the arc and analyzed for determination of the main geochemical parameters. A chemical study reflects the physical and chemical processes undergone by these cold and thermal waters during their circulation through the different host rocks. The chemistry of the dissolved gases, are characterized by He and CO2 contents, 2 to 3 orders of magnitude higher than the ASW values implies very active gas-water interaction processes. Moreover, both dissolved and bubbling gases isotopic signature shows a wide compositional range, with Helium ranging between 0.1 to 7.12 R/Ra and carbon ranging from -1.75 to -10.50 13C(TDIC) vs PDB standard. Such isotopic features may be related to the presence of at least two distinct end-members: mantle and crustal.. Helium, Nitrogen, Carbon, Oxygen and Deuterium isotopic signatures will help us to identify and characterize the main end-members of fluids involved in Ecuador’s continental arc-volcanism. Moreover, on the basis of the chemistry of thermal waters and associated bubbling gases the characteristics and the potential resources of the different geothermal fields are being investigated.
    Description: Published
    Description: 525-541
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: gases ; isotopes ; Helium ; Nitrogen ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    Publication Date: 2021-06-07
    Description: Stromboli made in July 2002 from fixed positions, using an automated plume scanning technique. Spectral data were collected using a miniature ultraviolet spectrometer, and SO2 column amounts were derived with a differential optical absorption spectroscopy evaluation routine. Scanning through the plume was enabled by a 45 turning mirror affixed to the shaft of a computer controlled stepper motor, so that scattered skylight from incremental angles within the horizon-to-horizon scans was reflected into the field of view of the spectrometer. Each scan lasted _5 min and, by combining these data with wind speeds, average fluxes of 940, 14, and 280 Mg d_1 were obtained for Etna, Vulcano, and Stromboli, respectively. For comparative purposes, conventional road and airborne traverses were also made using this spectrometer, yielding fluxes of 850, 17, and 210 Mg d_1. The automated scanning technique has the advantage of obviating the need for time-consuming traverses underneath the plume and is well suited for longer-term telemetered deployments to provide sustained high time resolution flux data.
    Description: Gruppo Nazionale per Vulcanolgia (GNV), the EC 5th Framework project ‘‘MULTIMO’’, and NERC grant GR9/04655
    Description: Published
    Description: 2455
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: volcanic gas monitoring, remote sensing, SO2 emissions, DOAS,ultraviolet spectroscopy ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publication Date: 2021-01-11
    Description: We present a comprehensive processing tool for the real-time analysis of the source mechanism of very long period (VLP) seismic data based on waveform inversions performed in the frequency domain for a point source. A search for the source providing the best-fitting solution is conducted over a three-dimensional grid of assumed source locations, in which the Green’s functions associated with each point source are calculated by finite differences using the reciprocal relation between source and receiver. Tests performed on 62 nodes of a Linux cluster indicate that the waveform inversion and search for the best-fitting signal over 100,000 point sources require roughly 30 s of processing time for a 2-min-long record. The procedure is applied to post-processing of a data archive and to continuous automatic inversion of real-time data at Stromboli, providing insights into different modes of degassing at this volcano
    Description: Published
    Description: L04301
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 6
    Publication Date: 2021-01-27
    Description: The Sciara del Fuoco (SdF) landslides that occurred at the end of December 2002 prompted researchers to install geodetic networks to monitor deformations related to potential new slope failures. With this aim, an integrated multiparametric monitoring system was designed and deployed. In particular, this complex monitoring system is composed of four single systems: an electronic distance measurement network, installed immediately after the landslide events, a realtime GPS network, a ground-based interferometric linear synthetic aperture radar (GB-InSAR), and an automated topographic monitoring system (named Theodolite Robotic Observatory of Stromboli, or THEODOROS); the three last systems provided a continuous monitoring of selected points or sectors of the SdF. Data acquired from different systems have been jointly analyzed to reach a better understanding of the SdF dynamics. Displacement data obtained from the topographic systems are compared with those obtained from GB-InSAR, and the results of the comparison are analyzed and discussed. Furthermore, in this chapter, an example of a warning system that can detect slope instability precursors on the SdF based on a statistical analysis of the data collected by the THEODOROS system is reported.
    Description: Published
    Description: 183-199
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: reserved
    Keywords: Flank instability ; Slope failure ; Terrestrial geodesy ; Ground Based InSAR ; Continuous GPS ; Landslide monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2021-04-07
    Description: We present the results of a study of volcanic gases at Soufrière Hills Volcano, Montserrat, which includes the first spectroscopic measurements of the major gas species CO2 and H2S at this volcano using a Multisensor Gas Analyzer System (MultiGAS) sensor. The fluxes of CO2 and H2S were 640–2750 t/d and 84–266 t/d, respectively, during July 2008, during a prolonged eruptive pause. The flux of CO2 is similar to estimates for the entire arc from previous geochemical studies, while the measured H2S flux significantly alters our interpretation of the sulphur budget for this volcano. The fluxes of both sulphur and carbon show considerable excesses over that which can be supplied by degassing of erupted magma. We demonstrate, using thermodynamic models and published constraints on preeruptive volatile concentrations, that the gas composition and fluxes are best modeled by mixing between (1) gases derived from isobaric quenching of mafic magma against cooler andesite magma at depth and (2) gases derived from shallower rhyolitic interstitial melt within the porpyritic andesite. The escape of deep‐derived gases requires pervasive permeability or vapor advection extending to several kilometers depth in the conduit and magma storage system. These results provide more compelling evidence for both the contribution of unerupted mafic magma to the volatile budget of this andesitic arc volcano and the importance of the intruding mafic magma in sustaining the eruption. From a broader perspective, this study illustrates the importance and role of underplating mafic magmas in arc settings. These magmas play an important role in triggering and sustaining eruptions and contribute in a highly significant way to the volatile budget of arc volcanoes.
    Description: Published
    Description: Q04005
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: magma degassing ; thermodynamics ; volcanic gases ; Soufriere Hills ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 8
    Publication Date: 2017-04-04
    Description: Ground-based thermal imaging is becoming an increasingly important tool for volcano surveillance, however the impact of volcanic plumes on quantitative measurements of surface temperature has not been previously evaluated. Here we use a radiative transfer model to simulate gas (primarily H2O and SO2) and aerosol absorptions over the path between a thermal camera and a heat source on Stromboli volcano, Italy. A FTIR spectrometer was used to quantify path amounts of gases likely to be encountered when making thermal measurements of the active craters. We find that when using a camera sensitive from 7.5 to 13 mm, underestimates of 400 K may be produced when viewing a source with an actual temperature of 1200 K. Cameras that operate between 3 and 5 mm are somewhat less susceptible to these errors.
    Description: Published
    Description: L14311
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 9
    Publication Date: 2017-04-04
    Description: Late on the night of 26 October 2002, a dike intrusion started suddenly at Mount Etna, producing intense explosive activity and lava effusion on the southern flank. Five to six hours afterward, a long field of eruptive fractures propagated radially along the northeastern flank of the volcano, producing marked variations at the permanent tilt network. The dike propagation velocity was inferred by the associated seismicity. We modeled the temporal evolution of the continuously recorded tilt data, both during the vertical dike propagation on the high south flank on 26 October and during the radial propagation along the northeast flank, between 27 and 28 October. The reproduction of the recorded tilt signal allowed us to describe the geometry and characteristics of the two dikes in greater detail than the previous static inversion. We deduced that the eruption was characterized by an unusual composite mechanism, clearly showing a transition from a nearly pure opening mode displacement to a mechanism characterized by an equally strong normal dip-slip component and a smaller left lateral strike-slip component. In this study we demonstrate the interaction between the final segment of the dike and a preexisting structure that was reactivated in response to the intrusion. We show that tilt and its modeling represent a powerful tool to verify and constrain dike intrusions in detail.
    Description: Published
    Description: B06404,
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 10
    Publication Date: 2017-04-04
    Description: Independent component analysis (ICA) is a recent and well-known technique used to separate mixtures of signals. This technique has been applied to the ground deformation time-series recorded at the permanent GPS network of the Osservatorio Vesuviano—INGV in order to characterize the deformation background level in the Neapolitan volcanic area. The analysis revealed the presence of five independent periodic signals common at all the GPS stations; some of them are interpreted as effects of earth tides. The residual signal at each station represent the local ground deformation. Unfortunately the ICA cannot provide the absolute amplitude of the components, indeed we are not able to obtain a residual amplitude at each station. Then we used a stationarity analysis in order to investigate the eventual presence of local transient deformations. The ICA technique combined with the stationarity analysis has shown to be a very interesting tool for individuating ground deformation trends and could be very useful in volcanic areas monitoring.
    Description: Published
    Description: 1305–1310
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: independent component analysis ; ground deformationin ; signal processing ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2017-04-04
    Description: A permanent automatic infrared (IR) station was installed at Solfatara crater, the most active zone of Campi Flegrei caldera. After a positive in situ calibration of the IR camera, we analyze 2175 thermal IR images of the same scene from 2004 to 2007. The scene includes a portion of the steam heated hot soils of Solfatara. The experiment was initiated to detect and quantify temperature changes of the shallow thermal structure of a quiescent volcano such as Solfatara over long periods. Ambient temperature results as the main parameter affecting IR temperatures while air humidity and rain control image quality. A geometric correction of the images was necessary to remove the effects of slow movement of the camera. After a suitable correction the images give a reliable and detailed picture of the temperature changes, over the period October 2004 – January 2007, which suggests origin of the changes were linked to anthropogenic activity, vegetation growth and to the increase of the flux of hydrothermal fluids in the area of the hottest fumaroles. Two positive temperature anomalies were registered after the occurrence of two seismic swarms which affected the hydrothermal system of Solfatara in October 2005 and October 2006. It is worth noting that these signs were detected in a system characterized by a low level of activity with respect to systems affected by real volcanic crisis where more spectacular results will be expected. Results of the experiment show that this kind of monitoring system can be a suitable tool for volcanic surveillance.
    Description: Published
    Description: B12206
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: partially_open
    Keywords: Termal Monitoring of Hydrothermal ; Activity ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 12
    Publication Date: 2017-04-04
    Description: Ground deformation data from GPS and differential synthetic aperture radar interferometry (DInSAR) techniques are analyzed to study the July–August 2001 Mount Etna eruption as well as the dynamics preceding and following this event. Five GPS surveys were carried out on the entire Mount Etna network or on its southeastern part, from July 2000 to October 2001. Five ERS-2 ascending passes and three descending ones are used to form five interferograms spanning periods from a month to 1 year, before and encompassing the eruption. Numerical and analytical inversions of the GPS and DInSAR data were performed to obtain analytical models for preeruptive, syneruptive and posteruptive periods. The deformation sources obtained were from the Mogi model: (1) pressure sources located beneath the upper western flank of the volcano, inflating before the eruption onset and deflating afterward; (2) tensile dislocations to model the intrusion of a N-S dike in the central part of the volcano; and (3) two sliding and two normal dislocations to model the eastern and southern flank dynamics. This study confirms that the lower vents of the eruption were fed by a magma stored at depth ranging from 9 to 4 km below sea level, as proposed from petrochemical and geophysical researches. The rising of the magma through the shallow crust started months before the eruption onset but accelerated on the last day; this study suggests that in the volcanic pile the path of the rising magma was driven by the volcano topography. The eastern sliding plane and the interaction between dike intrusion and flank instability have been better defined with respect to previous studies. The sliding motion abruptly accelerated with the dike intrusion, and this continued after the end of the eruption. The acceleration was accompanied by the propagation of the strain field toward the eastern periphery of the volcano.
    Description: We acknowledge the ‘‘Istituto Nazionale di Geofisica e Vulcanologia’’, the Italian ‘‘Dipartimento per la Protezione Civile’’ and the European Community (contract INGV-DPC UR V3_6/36 and VOLUME Project) for their economic contribution to this research. The SAR data are provided by ESA-ESRIN.
    Description: Published
    Description: B06405
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Ground deformation ; GPS ; InSAR ; Mt. Etna ; Modelling ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 13
    Publication Date: 2017-04-04
    Description: Helium isotope ratios of olivine and pyroxene phenocrysts from Plio-Quaternary volcanic rocks from southern Italy (seven Aeolian Islands, Mt. Vulture, Etna, Ustica, and Pantelleria) range from 2.3 to 7.1 Ra. Importantly, the phenocryst 3He/4He correlate well with whole rock Sr isotopic composition (0.70309– 0.70711), reflecting the mixing of two sources. A significant contribution of He from crustal contamination is recorded only occasionally (e.g., pyroxenes from Vulcano). When merged with data from the Roman Comagmatic Province, a remarkably strong near-linear He-Sr isotope correlation is apparent. The general northward decrease in 3He/4He corresponds to an increase in 87Sr/86Sr (and a decrease in 143Nd/144Nd and 206Pb/204Pb) that is due to increasing metasomatic enrichment of the mantle wedge via subduction of the Ionian-Adriatic plate. Calculations based on the ingrowth of 4He in the wedge and on the 4He content of the subducting crust show that mechanisms of enrichment in radiogenic He are effective only if the wedge is strongly depleted in He relative to best estimates of the depleted mantle. This can be accommodated if the process of metasomatism by the subduction fluids depletes the mantle wedge. The 3He/4He of Pantelleria, Etna, Iblei, Ustica, Alicudi, and Filicudi basalts (7.0 ± 0.6 Ra) define the mantle composition least affected by subduction-related metasomatism. Although these volcanoes are from a variety of tectonic regimes (subduction-related, intraplate, rifting), their similarities suggest a common origin of geochemical features. Their characteristics are consistent with a HIMU-type mantle that either is younger than the Cook- Austral island end-member or has a lower 238U/204Pb.
    Description: Published
    Description: Q02001
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: helium ; strontium ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 14
    Publication Date: 2017-04-04
    Description: On two occasions, sudden gravity changes occurred simultaneously at two summit Etna’s stations, during local low-magnitude earthquakes. A systematic coupling between earthquakes inducing comparable maximum acceleration and displacement at the observation points and gravity steps is missing, implying (1) the non-instrumental nature of the steps and (2) the need for particular underlying conditions for the triggering mechanism(s) to activate. We review some of the volcanological processes that could induce fast underground mass redistributions, resulting in gravity changes at the surface. These processes involve bubbles and crystals present in the magma and require particular conditions in order to be effective as mass-redistributing processes. The gravity steps could be a geophysical evidence of the dynamical stress transfer between tectonic and magmatic systems at a local scale. Given the implications that these transfers may have on the volcanic activity, routine volcano monitoring should include the observation of fast gravity changes.
    Description: Published
    Description: L02301
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: open
    Keywords: gravity step ; dynamical stress transfer ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 15
    Publication Date: 2012-02-03
    Description: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.
    Description: The low‐intensity activity of basaltic volcanoes is occasionally interrupted by short‐lived but energetic explosions which, whilst frequently observed, are amongst the most enigmatic volcanic events in Nature. The combination of poorly understood and deep, challenging to measure, source processes make such events currently impossible to forecast. Here we report increases in quiescent degassing CO2 emissions (〉10,000 t/day) prior to a powerful explosive event on Stromboli volcano on 15 March 2007. We interpret such large CO2 flux as being sourced by passive gas leakage from a deeply (〉4 km) stored magma, whose depressurization, possibly caused by the onset of an effusive eruption on 28 February 2007, was the explosion trigger. Our observations suggest that continuous CO2 flux monitoring may allow anomalously large explosions to be accurately forecast at basaltic volcanoes.
    Description: Funding from INGV‐DPC project Paroxysm
    Description: Published
    Description: L17303
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: CO2, UV scanner, Stromboli ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 16
    Publication Date: 2012-02-03
    Description: The Kasatochi 2008 eruption was detected by several infrared satellite sensors including Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Very High Resolution Radiometer (AVHRR), and Atmospheric Infrared Sounder (AIRS). In this work a comparison between the volcanic cloud SO2 and ash retrievals derived from these instruments has been undertaken. The SO2 retrieval is carried out by using both the 7.3 and 8.7 micron absorption features while ash retrieval exploits the 10–12 micron atmospheric window. A radiative transfer scheme is also used to correct the volcanic ash effect on the 8.7 micron SO2 signature. As test cases, three near‐contemporary images for each sensor, collected during the first days of the eruption, have been analyzed. The results show that the volcanic SO2 and ash are simultaneously present and generally collocated. The MODIS and AVHRR total ash mass loadings are in good agreement and estimated to be about 0.5 Tg, while the AIRS retrievals are slightly lower and equal to about 0.3 Tg. The AIRS and MODIS 7.3 micron SO2 mass loadings are also in good agreement and vary between 0.3 and 1.2 Tg, while the MODIS ash corrected 8.7 micron SO2 masses vary between 0.4 and 2.7 Tg. The mass increase with time confirms the continuous SO2 injection in the atmosphere after the main explosive episodes. Moreover the difference between the 7.3 and 8.7 micron retrievals suggests a vertical stratification of the volcanic cloud. The results also confirm the importance of the ash correction; the corrected 8.7 micron SO2 total masses are less than 30–40% of the uncorrected values.
    Description: Published
    Description: D00L21
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: reserved
    Keywords: Remote sensing ; ash retrieval ; SO2 retrieval ; multispectral satellite instruments ; MODIS ; AVHRR ; AIRS ; hyperspectral satellite instruments ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 17
    Publication Date: 2017-04-04
    Description: To recognize possible signals of intrusive processes leading to the last 2002–2003 flank eruption at Mt. Etna, we analyzed the spatial pattern of microseismicity between August 2001 and October 2002 and calculated 23 fault plane solutions (FPSs) for shocks with magnitude greater than 2.5. By applying the double-difference approach of Waldhauser and Ellsworth [2000] on 3D locations, we found that most of the scattered epicentral locations further collapse in roughly linear features. High-precision locations evidenced a distribution of earthquakes along two main alignments, oriented NE-SW to ENE-WSW and NW-SE, matching well both with the known tectonic and volcanic lineaments of Etna and FPSs results. Moreover, microseismicity and swarms located along the NNW-SSE volcano-genetic trend suggest, together with geodetic data and volcanological evidence that progressive magma refilling has occurred since February 2002.
    Description: Published
    Description: 1-4
    Description: partially_open
    Keywords: Seismology: Earthquake dynamics and mechanics ; Seismology: Earthquake parameters ; Seismology: Volcano seismology ; Volcanology: Eruption monitoring ; Volcanology: Magma migration. ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 18
    Publication Date: 2017-04-04
    Description: The Stromboli volcano (Aeolian Islands, Italy) erupted suddenly on 28 December 2002 after a 17-year period of typically persistent but moderate eruptive activity, followed two days later by a tsunamigenic landslide on its NW flank (Sciara del Fuoco) felt in the coastal areas of southern Italy. Three continuous GPS stations were quickly deployed near the volcano's rim sampling at 1 Hz, with instantaneous positions computed relative to a fourth station on its flank. We report on two deformation episodes. A vent migration on 16–17 February 2003 caused significant displacements at only one site and contributed to the decision not to issue a warning of an impending tsunamigenic landslide. The second episode on 5 April 2003, a paroxystic explosion from the summit crater, allowed us to model, for the first time with geodetic data, the shallow magma chambers that give rise to Strombolian explosive activity.
    Description: Published
    Description: 1-4
    Description: partially_open
    Keywords: Mathematical Geophysics: Modeling ; Tectonophysics: Physics of magma and magma bodies ; Volcanology: Eruption mechanisms ; Volcanology: Eruption monitoring ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 19
    Publication Date: 2017-04-04
    Description: Soil radon emissions have been proved as a useful tool for predicting earthquakes and volcanic eruptions and furthermore aided in determining the location of active faults. Continuous radon monitoring was carried out near Southeast Crater of Mt. Etna in September–November 1998, during a period of frequent eruptive episodes at that crater. Radon anomalies were detected when eruptive episodes and the accompanying volcanic tremor became increasingly intense: no anomalies in radon activity were observed during the first five, and weaker, eruptive episodes, whereas significant spikes in radon activity preceded the latter five episodes by ≥46 hours. This probably reflects increased gas leakage through fractures intersecting the shallow plumbing system, as gas pressure in the Southeast Crater conduit became higher with time. Radon monitoring thus might serve to better understand eruptive mechanisms and possible precursors, making further studies in this field a promising perspective.
    Description: Published
    Description: 1-4
    Description: partially_open
    Keywords: Seismology: Volcano seismology ; Structural Geology: Role of fluids ; Volcanology: Volcano monitoring ; Volcanology: Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 20
    Publication Date: 2017-04-04
    Description: Effusive activity at Stromboli is uncommon, and the 2002–2003 flank eruption gave us the opportunity to observe and analyze a number of complex volcanic processes. In particular, the use of a handheld thermal camera during the eruption allowed us to monitor the volcano even in difficult weather and operating conditions. Regular helicopter-borne surveys with the thermal camera throughout the eruption have significantly improved (1) mapping of active lava flows; (2) detection of new cracks, landslide scars, and obstructions forming within and on the flanks of active craters; (3) observation of active lava flow field features, such as location of new vents, tube systems, tumuli, and hornitos; (4) identification of active vent migration along the Sciara del Fuoco; (5) monitoring of crater's inner morphology and maximum temperature, revealing magma level changes within the feeding conduit; and (6) detection of lava flow field endogenous growth. Additionally, a new system developed by A. J. L. Harris and others has been applied to our thermal data, allowing daily calculation of effusion rate. These observations give us new insights on the mechanisms controlling the volcanic system.
    Description: Published
    Description: 1-23
    Description: partially_open
    Keywords: volcano monitoring ; thermal mapping ; flank eruption ; Stromboli volcano ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 21
    Publication Date: 2017-04-04
    Description: The peculiarity of the quiescent La Fossa volcano is the occurrence of ‘‘crises’’ characterized by strong increases of fumarole T and output and by chemical changes indicative of an increasing input of magmatic fluids. Several surveys carried out during a new ‘‘crisis’’ began in November 2004 indicate that the total diffuse CO2 emission for the crater area increases by one order of magnitude during crises (up to 1600 ton d 1 in December 2005). Concern exists on the possibility that these crises be related to an unrest process leading to eruption. The repetition along decades of the same gas compositional variations during crises, their temporal coincidence with increases of the local shallow seismicity, and the lack of any significant ground motion, rather suggest that they correspond to moments of increasing volatile release from a stationary magma system.
    Description: Published
    Description: L13316
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 22
    Publication Date: 2017-04-04
    Description: Continuous soil radon monitoring was carried out near the Southeast Crater (SEC) of Mt. Etna during the 10-day July 2006 Strombolian-effusive eruption. This signal was compared with simultaneously acquired volcanic tremor and thermal radiance data. The onset of explosive activity and a lava fountaining episode were preceded by some hours with increases in radon soil emission by 4–5 orders of magnitude, which we interpret as precursors. Minor changes in eruptive behavior did not produce significant variations in the monitored parameters. The remarkably high radon concentrations we observed are unprecedented in the literature. We interpret peaks in radon activity as due primarily to microfracturing of uranium-bearing rock. These observations suggest that radon measurements in the summit area of Etna are strongly controlled by the state of stress within the volcano and demonstrate the usefulness of radon data acquisition before and during eruptions.
    Description: Published
    Description: L24316
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 23
    Publication Date: 2017-04-03
    Description: Levelling surveys carried out between 1990 and 2003 on the Mt Epomeo resurgent block (Ischia Island) record negative dislocations on its northern and southern flanks with a maximum subsidence rate of 1.27 cm yr)1. This deformation is not associated with the cooling, crystallization or lateral drainage of magma and cannot be explained by a pressure point or prolate ellipsoid source. Results from dislocation models and the available structural and geochemical information indicate that the subsidence is due to crack closure processes along two main ENE–WSW and E–W preexisting faults, which represent the preferred pathway of CO2 degassing from the hydrothermal system located beneath Mt Epomeo. The monitoring of the dislocations and CO2 flux along these faults could give useful information on the dynamics of the hydrothermal system.
    Description: Published
    Description: 127-132
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: open
    Keywords: fluid flow ; fracture ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 24
    Publication Date: 2017-04-04
    Description: Two swarms of microearthquakes (ML ≤ 2.2), occurred on July 2-7 and August 22, 2000 at Campi Flegrei, accompained by a ground uplift episode (4 cm) which interrupted on early March 2000 the descending trend started on 1985. Spectral analysis indicates a direct involvement of magmatic/hydrothermal fluids in the source process of the July swarm, while the August events are typical of shear failure, similar to most of the earthquakes that occurred during the last (1982-1984) bradyseismic crisis. Precise 3-D relative location applied to similar earthquakes allows for the recognition of two parallel alignments trending NE-SW at depths of 1.7 and 3.2 Km. This trend is consistent with the direction of the main focal plane obtained from fault plane solutions and evidences tensile failure in close proximity to the zone of maximum uplift as depicted by geodetic measurements. A fault weakening mechanism triggered by increasing pore pressure is invoked as the cause of these earthquakes.
    Description: Published
    Description: 2525-2528
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Campi Flegrei ; seismic swarm ; earthquakes locations ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 25
    Publication Date: 2017-04-04
    Description: An accurate description of the geochemical system is presented here based on a review of scientific work performed during the past decade. The surface manifestations of the volcanic system of Stromboli have been investigated using several measuring techniques. Studying the chemical composition of the volcanic plume and of fumarolic emissions has provided information on magma degassing processes. The total fluxes of the emitted gases from both the plume and the soil were found to vary with changes in volcanic activity (from normal Strombolian activity to effusive and/or paroxysmal activity). Thermal water results from the interaction between volcanic gases, host rock, seawater and meteoric water and temporal changes observed in the chemical and the isotopic composition of the gases dissolved into thermal waters highlighted the rising of new magma batches. Combining modelling of gas-water-rock interactions with an understanding of the volcanic system allowed to identify preferential sampling sites and parameters for the geochemical monitoring of volcanic activity at Stromboli Island.
    Description: Unpublished
    Description: 16
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: open
    Keywords: Water geochemistry ; Volcanic surveillance ; Stromboli ; Gas geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 26
    Publication Date: 2017-04-04
    Description: Geochemical surveillance has been carried out at Stromboli since 1999 using discrete and continuous monitoring of thermal waters and soil degassing. On 27 February 2007 a new eruption began which lasted until 2 April; it was characterized by effusive activity on the Sciara del Fuoco and also by a paroxistic event (15 March). This crisis represented an opportunity to refine the model developed previously and to improve our understanding of the relationship between the magmatic dynamics of the volcano and geochemical variations. The main aim of this research was to evaluate the level of criticality of the volcanic activity. The SO2 fluxes of the degassing plume and the CO2 fluxes emitted from the soil at Pizzo Sopra la Fossa are herein presented. Furthermore, we propose a refined geochemical model of fluids circulation, including plume and summit fumarolic soil degassing. Noteworthy geochemical signals of volcanic unrest were also clearly identified (before, during and after the effusive activity) in the degassing plume as well as in the degassing from the soil at the summit.
    Description: Published
    Description: San Francisco, CA,USA
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: open
    Keywords: CO2 flux ; Stromboli volcano ; SO2 Flux ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
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  • 27
    Publication Date: 2017-04-04
    Description: The Total Volatile (TV) flux from Mount Etna volcano has been characterised for the first time, by summing the simultaneously-evaluated fluxes of the three main volcanogenic volatiles: H2O, CO2 and SO2.SO2 flux was determined by routine DOAS traverse measurements, while H2O and CO2 were evaluated by scaling MultiGAS-sensed H2O/SO2 and CO2/SO2 plume ratios to the UV-sensed SO2 flux. The time-averaged TV flux from Etna is evaluated at ~21,000 t∙day-1, with a large fraction accounted for by H2O(~13,000 t∙day-1). H2O dominates (≥70%) the volatile budget during syn-eruptive degassing, while CO2 and H2O contribute equally to the TV flux during passive degassing. The CO2 flux was observed to be particularly high prior to the 2006 eruption, suggesting that this parameter is a good candidate for eruption prediction at basaltic volcanoes.
    Description: Published
    Description: L24302
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Active volcanoes ; Volcanic monitoring ; Gas ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 28
    Publication Date: 2017-04-04
    Description: In this paper we describe the experiences and results gained in the use of tiltmeters at Mt. Etna during the last twenty years. The tilt data represent a fundamental contribution to understanding of volcanic phenomena. Moreover, the tilt played an important role in analytic modelling, of the sources linked to the most important recent lateral eruptions. The tilt data also provided evidence of co-seismic variations for higher energy and shallower seismic events. We also discuss the marked variations that often occur over the entire volcano edifice without being associated with seismicity or eruptive activity. This work also analyses and discusses experiments conducted to verify the limitations of shallow borehole sensors. The main causes of noise are the thermo-elastic effects on the ground and the spurious effects on the sensor due to temperature variations. To this end, results of recent experiments to verify the theoretical filtering of thermal noise at depth and to examine the real thermal coefficients of the sensors through a patented instrument are discussed. Finally, results obtained from signal recordings, applied theoretical studies, experiments performed and technological advances have recently suggested new horizons for tilt monitoring through the development of innovative instrumentation. We describe the application of new technology for the detection of tilt by a long base fluid tiltmeter, installed in 1997, which is able to record very stable, high precision signals with very low noise, thus allowing more detailed investigation of the different phases of volcanic activity.
    Description: Published
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: reserved
    Keywords: Tiltmeter ; Modeling ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book
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  • 29
    Publication Date: 2017-04-04
    Description: Deformation data collected at Mount Etna from 1993 to 1997 show that the inflation of the volcano edifice is accompanied by instability of the eastern flank. We propose a 3-D finite element model including topography and lateral variations of elastic constants. Source parameters of the inflating source are constrained by a direct search followed by an appraisal stage of the sampled solutions. The instability of the eastern flank is addressed using a kinematic approach, consisting of a rigid-body translation over a prescribed area. The aim is to evaluate how source parameters are affected by sliding of the eastern flank. When sliding is accounted for, the inferred source location shifts ∼1 km SE and its strength decreases by ∼20 per cent.
    Description: Published
    Description: 806-814
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Numerical solutions ; Inverse theory ; Radar interferometry ; Crustal structure ; Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 30
    Publication Date: 2017-04-04
    Description: From early September to early November, during the 2004–2005 Mt. Etna effusive eruption, petrologic monitoring was enabled by near-vent sampling of erupting lava and onsite SEM-EDS capabilities at INGV-CT. Significant differences in composition and temperature of lava erupted from 2920–2620 m and 2820–2320 m vents, attest to variably evolved shallow magmatic conditions within a geometrically complex storage volume. The petrography and glass compositions of water-quenched samples indicate that the magma feeding the 2004–2005 activity was likely to have been stored in the shallow plumbing system during the 2000 and 2001 activity, where it experienced volatile loss and extensive crystallization. Both geophysical and petrologic data suggest that this eruption was not triggered by the intrusion of a new dike from depth, but it was more likely that existing shallow magma reservoirs were passively mobilized and erupted in response to edifice deformation.
    Description: Published
    Description: 1-5
    Description: partially_open
    Keywords: Mineralogy and Petrology: Petrography, microstructures, and textures ; Mineralogy and Petrology: Igneous petrology ; Volcanology: Eruption mechanisms and flow emplacement ; Volcanology: Volcano monitoring ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 31
    Publication Date: 2017-04-04
    Description: The understanding of shallow intrusive processes during 2002–2004, as well as the causes of the volcano-tectonic seismicity, has been improved at Mt. Etna by comparing the inversion results from GPS data with accurate 3D hypocentral locations. Our findings indicate that short periods of deflation (about six months) were followed by recharging phases after the end of both the 2001 and 2002–2003 flank eruptions. During the last recharging phase (June 2003–August 2004), modeling results and seismic observations suggest a composite mechanism of re-injection of magma into the rift-zones (S and NE), similar to that leading to the 2002–2003 flank eruption, which could have triggered the summit eruption started on September 7, 2004.
    Description: Published
    Description: 1-4
    Description: partially_open
    Keywords: Volcanology: Magma migration and fragmentation ; Seismology: Earthquake interaction, forecasting, and prediction ; Seismology: Seismicity and tectonics ; Volcanology: Volcano monitoring ; Volcanology: Eruption mechanisms and flow emplacement ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 32
    Publication Date: 2017-04-04
    Description: A selected dataset of 151 events, leading the July 17–August 9, 2001 lateral eruption at Mt. Etna volcano, has been analyzed for three-dimensional hypocenter locations, focal mechanisms and stress tensor inversions. The seismic pattern provided indications for two main spatial clusters of foci located along and eastwards of the 2001 Mt. Etna eruptive fractures system. The 151 fault plane solutions (mostly strike slip) were inverted for stress tensor parameters, and space variations of seismogenic stress orientations have been identified. The stress inversion results and the axi-symmetric orientation of P-axes, in the region surrounding the modeled dike, well support the evidence of a unique stress source in agreement with the ground deformation results.
    Description: Published
    Description: 1-4
    Description: partially_open
    Keywords: Seismology: Volcano seismology ; Volcanology: Eruption mechanisms ; Volcanology: Magma migration ; Volcanology: Eruption monitoring. ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 33
    Publication Date: 2017-04-04
    Description: The 2004–05 eruption of Etna was characterised by outpouring of degassed lava from two vents within Valle del Bove. After three months of eruption lava volumes were estimated to be between 18.5 and 32 × 106 m3, with eruption rate between 2.3 and 4.1 m3/s. Petrological analyses show that magma is resident in the shallow plumbing system, emplaced during the last South-East Crater activity. SO2 flux data show no increase at the onset of the eruption and SO2/HCl ratios in gas emitted from the eruptive fissure are consistent with a degassed magma. No seismic activity was recorded prior to eruption, unlike eruptions observed since the 1980's. The purely effusive nature of this eruption, fed by a degassed, resident magma and the fracture dynamics suggest that magmatic overpressure played a limited role in this eruption. Rather, lateral spreading of Etna's eastern flank combined with general inflation of the edifice triggered a geodynamically-controlled eruption.
    Description: Published
    Description: 1-4
    Description: partially_open
    Keywords: Volcanology: Effusive volcanism ; Volcanology: Volcano monitoring ; Volcanology: Eruption mechanisms and flow emplacement ; Volcanology: General or miscellaneous ; Tectonophysics: Tectonics and magmatism ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 34
    Publication Date: 2017-04-04
    Description: The 2002–2003 Mount Etna eruption and the associated deformation provide a unique possibility to study the relationships between volcanism and volcano instability. The sequence started with movement of the eastern volcano flank and was associated with earthquakes and the formation of surface ruptures. Then the eruption occurred from fissures at the north and south rift zones and was followed by additional flank movement, seismic swarms, and surface ruptures. The overall area of flank movement implicated more than 700 km2. In this paper we investigate how episodes of magmatic events (eruptions and intrusions) and flank movement interact. In three-dimensional numerical models we simulate the volcano-tectonic events and calculate changes in the static stress field. The models suggest that the 2002–2003 events are the result of interrelated processes consisting of (1) the preeruptive intrusion of magma and inflation of the volcano, which induced (2) the movement of the volcano east flank, (3) facilitated the eruption, and (4) led to the slip of a much larger part of the eastern and southeastern flanks. Understanding the precise interconnectivity of these processes may help to forecast the behavior during future volcanic crisis at Mount Etna, which is crucial in minimizing volcanic and seismic hazards on the highly populated eastern sector of the volcano.
    Description: Published
    Description: 1-12
    Description: partially_open
    Keywords: Mount Etna ; flank instability ; volcano deformation ; volcano-tectonic interaction ; elastic stress field modeling ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 35
    Publication Date: 2017-04-04
    Description: SO2 flux is widely monitored on active volcanoes as it gives a window into the hidden, subsurface magma dynamics. We present here a new approach to SO2 flux monitoring using ultraviolet imaging of the volcanic plume through carefully chosen filters to produce images of SO2 column amount. The SO2 camera heralds a breakthrough in both our ability to measure SO2 flux at unprecedented frequencies (2 Hz) and at unprecedented accuracy, thanks to the application of correlation techniques to determine wind speed directly from the images and the ability to measure the whole profile simultaneously. In this paper we detail the commercially available pieces required to construct the SO2 camera, introduce a retrieval scheme to determine SO2 amounts from the images and present results from a field campaign in November 2005 on Sakurajima volcano, Japan.
    Description: Published
    Description: L24804
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 36
    Publication Date: 2017-04-04
    Description: Measurements of 220Rn and 222Rn activity and of CO2 flux in soil and fumaroles were carried out on Mount Etna volcano in 2005–2006, both in its summit area and along active faults on its flanks. We observe an empirical relationship between (220Rn/222Rn) and CO2 efflux. The higher the flux of CO2, the lower the ratio between 220Rn and 222Rn. Deep sources of gas are characterized by high 222Rn activity and high CO2 efflux, whereas shallow sources are indicated by high 220Rn activity and relatively low CO2 efflux. Excess 220Rn highlights sites of ongoing shallow rock fracturing that could be affected by collapse, as in the case of the rim of an active vent. Depletion both in 220Rn and in CO2 seems to be representative of residual degassing along recently active eruptive vents.
    Description: Published
    Description: Q10001
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: radon ; thoron ; carbon dioxide ; rock stress ; gas transport ; Mount Etna ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 37
    Publication Date: 2017-04-04
    Description: The early stages of the 2002–2003 lateral eruption at Mount Etna were accompanied by slow changes (over some hours) and some rapid step offsets in the local magnetic field. At five monitoring locations, the total magnetic field intensity has been measured using continuously operating Overhauser magnetometers at a sampling rate of 10 s. The very unique aspect of these observations is the close temporal correspondence between magnetic field offsets and earthquakes that occurred in the upper northern flank of the volcano on 27 October 2002 prior to a primary eruption. Rapid coseismic changes of the magnetic field were clearly identified for three of the most energetic earthquakes, which were concentrated along the Northeast Rift at a depth of about 1 km below sea level. Coseismic magnetic signals, with amplitudes from 0.5 to 2.5 nT, have been detected for three of the largest seismic events located roughly midway between the magnetic stations. We quantitatively examine possible geophysical mechanisms, which could cause the magnetic anomalies. The comparison between magnetic data, seismicity and surface phenomena implies that piezomagnetic effects are the primary physical mechanism responsible for the observed magnetic anomalies although the detailed cause of the rapid high stress change required is not clear. The modeling of the observed coseismic magnetic changes in terms of piezomagnetic mechanism provides further evidence of the complex interaction between volcanic and tectonic processes during dike propagation along the Northeast Rift.
    Description: Published
    Description: B09103
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: piezomagnetism ; earthquakes ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 38
    Publication Date: 2017-04-04
    Description: We investigated the gas geochemistry of fumaroles close to the Voragine crater of Mt Etna that have a temperature of 90–95 C, are CO2-dominated, and have an air content as low as 〈1%. This is the first report of the monitoring of such air-free fumaroles at the Etnean crater area—previous studies indicated an air contribution of 70% or more. The helium and carbon isotopes (Rc/Ra = 6.5 ± 0.4, d13CCO2 = 1.7 ± 0.5%) suggest that the released gas is directly related to the magmatic degassing. The fumaroles were sampled 12 times between June 2007 and June 2008, which revealed an increase in Rc/Ra from 6.1 to 6.9 that can be related to the increasing volcanic activity at the summit area of Mt Etna. These fumaroles offer a new tool for detecting magmatic processes (magma ascent, refilling, degassing, etc.), and will be useful for volcano surveillance.
    Description: Published
    Description: L21302
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: helium ; isotope ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
    Publication Date: 2017-04-04
    Description: We report measurements of Hg, SO2, and halogens (HCl, HBr, HI) in volcanic gases from Masaya volcano, Nicaragua, and gaseous SO2 and halogens from Telica volcano, Nicaragua. Mercury measurements were made with a Lumex 915+ portable mercury vapor analyzer and gold traps, while halogens, CO2 and S species were monitored with a portable multi gas sensor and filter packs. Lumex Hg concentrations in the plume were consistently above background and ranged up to 350 ng/m3. Hg/SO2 mass ratios measured with the real-time instruments ranged from 1.1*10-7 to 3.5*10-5 (mean 2*10-5). Total gaseous mercury TGM)concentrations measured by gold trap ranged from 100 to 225 ng/m3. Reactive gaseous mercury accounted for 1% of TGM, while particulate mercury was 5% of the TGM. Field measurements of Masaya’s SO2 flux, combined with the Hg/SO2 ratio, indicate a Hg flux from Masaya of 7.2 Mg/a-1. At Masaya’s low temperature fumaroles, Hg/CO2 mass ratios were consistently around 2*10-8, lower than observed in the main vent (Hg/CO2 10-7). Low-temperature fumarole Hg fluxes from Masaya are insignificant (150 g a-1). Ratios of S, C and halogen species were also measured at Masaya and Telica volcanoes. CO2/SO2 ratios at Masaya ranged from 2.8 to 3.9, comparable to previously published values. At Masaya molar Br/SO2 was 3*10-4 and I/SO2 was 2*10-5, suggesting fluxes of 0.2–0.5 Mg HBr d-1 and 0.02–0.05 Mg HI d-1. At Telica the Br/SO2 ratio was also 3*10-4 and the I/SO2 ratio was 5.8*10-5, with corresponding fluxes of 0.2 Mg HBr d-1 and 0.06 Mg HI d-1. Gases at both volcanoes are enriched in I relative to Br and Cl, compared to gases from volcanoes elsewhere.
    Description: This work was funded by NERC grant NE/ C511180/1/.
    Description: Published
    Description: B06203
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: Mercury ; Halogen ; Volcanic emissions ; Masaya volcano ; Telica volcano ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 40
    Publication Date: 2017-04-04
    Description: Five three-component broadband ocean bottom seismometers (OBSs) were deployed on the seafloor around the Aeolian Islands (Southern Tyrrhenian Sea). By comparing OBSs digital seismograms, we found a low-frequency seismicity recorded only at OBS05, the nearest seafloor station to Stromboli volcano. This seismicity appears in the form of a continuous seismic signal (tremor-like-signal) as well as a considerable number of shock-like events. We focused on recordings from OBS05 to verify their correlation with Stromboli volcanic activity. From the spectral analysis, we observed low-frequency events (LP events), superposed upon the continuous background noise (tremor). LP events and tremor, showing similar energy fluctuations and frequency content, appear to be produced by the same dynamic processes. We interpret this low-frequency seismicity as probably originating from a continuous uprising of gas bubbles from the deeper part of the Stromboli magmatic column. This could highlight the existence of a deeper source for low-frequency seismicity.
    Description: Published
    Description: L04305
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Volcano-seismology ; low-frequency events ; tremor ; OBSs ; Stromboli (Southern Tyrrhenian Sea) ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 41
    Publication Date: 2012-02-03
    Description: We present results from a campaign in March 2009 to assess the current state of emissions from Masaya Volcano, Nicaragua. These results constitute one of the most comprehensive inventories to date of emissions from an active volcano and update the exceptional record of emissions from Masaya. Results from open‐path Fourier transform infrared spectroscopy and filter packs demonstrate that, in terms of H2O, SO2,CO2, HCl,and HF (molar H2O/SO2 = 63, CO2/SO2 = 2.7, SO2/HCl = 1.7, SO2/HF = 8.8), the 2009 gas composition was highly comparable to that from the 1998 to 2000 period,indicating stability of the shallow magma system. This continuity extends to certain aerosol species (molar SO2/SO42−= 190, Na+ /SO4 2−= 0.68, K+/SO4 2−= 0.71, Ca 2+/SO4 2−= 1.6 × 10−2,Mg2+/SO4 2− = 3.6 × 10−3) and, to a lesser extent, the heavy halogens (i.e., molar HCl/HBr = 2.4 × 103 , HCl/HI = 5.0 × 104). In contrast to an arlier study at Masaya, we did not detect HNO3.SO2 fluxes were low (690 Mg d−1 ), suggesting that Masaya was close to the minimum of its degassing cycle. By combining compositional results with the SO2 flux, we estimate a total volatile flux of 14,000 Mg d−1. This rate is consistent with 1−4 wt% volatile loss from a convective magma flux of 17,000–4000 kg s−1. These results will allow for a better understanding of degassing processes at Masaya and other basaltic volcanoes
    Description: NERC project “Magma dynamics at persistently degassing basaltic volcanoes: A novel approach to linking volcanic gases and magmatic volatiles within a physical model” (NE/F004222/1 and NE/F005342/1).
    Description: Published
    Description: B09215
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Masaya Volcano ; Degassing regime ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 42
    Publication Date: 2017-04-04
    Description: After the end of the 2002–2003 eruption, Mount Etna activity was characterized only by gentle degassing at the summit craters and some earthquake swarms. Suddenly, an eruption started on 7 September 2004 in complete absence of summit crater volcanic activity, seismicity or seismic tremor, and ground deformation. This is the first time that magma poured out passively without preeruptive and coeruptive volcanic and/or geophysical phenomena. The primary key to understanding this event is represented by the ground deformation pattern recorded through GPS measurements during the year before the eruption. The ground deformation shows inflation superimposed by a predominant eastward movement of the eastern sector at a rate never observed before in a noneruptive period. The images from satellite radar interferometry confirmed this pattern. The deformation field clearly shows that the maximum tension in the eastern sector of the volcano caused the opening of the eruptive fracture which favored the silent pouring out of already resident magma.
    Description: Published
    Description: B12207
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 43
    Publication Date: 2017-04-04
    Description: We model the location, geometry and density of the source of the recent geological unrest at Campi Flegrei caldera (Italy) by inverting levelling, trilateration and gravity measurements collected between 1980 and 1995. The best fitting source for the 1980–84 inflation is a horizontal penny-shaped crack with a density 142 to 1115 kg/m3. The source best fitting the deflation period (1990–95) is a vertical spheroid with density between 902 and 1015 kg/m3. These results exclude the intrusion of magma, and indicate the migration of fluid to and from the caldera hydrothermal system as the cause of ground deformation and consequent unrest.
    Description: Published
    Description: L01307
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 44
    Publication Date: 2017-04-04
    Description: On 5 April 2003 at 07:13 GMT (09:13 local time) a violent vulcanian explosion occurred at Stromboli volcano. At the time of the event an eruptive crisis was ongoing at the volcano with a lava flow outpouring along the Sciara del Fuoco flank. The seismic signals related to the event were recorded by 8 permanent broadband stations and gives information about the eruption kinematics. An ultra-longperiod signal (period 〉 20 s), that we interpret as the effect of the ground tilt on the broadband sensors, starts about 4 min before and terminates about 1 min after the explosion. On the basis of the radial pattern of tilt directions we conclude that this signal is the effect of the deformation of the volcanic edifice, due to the rapid rising of a batch of magma, its ejection and the magma column readjustment. About 1 min before the explosion we observe an high frequency signal (period 〈 0.1 s) that we believe to be related to the vesiculation of the rising batch of gas-rich magma. At 07:13:35 GMT a powerful very-long-period signal (period 2 20 s), marking the onset of the explosive fragmentation, is recorded. This is confirmed by a blast wave following few seconds later. The remaining seismic signal (more than 3 min), shows an higher frequency content being related only to the fall of ballistic ejecta and to landslides along Sciara del Fuoco.We propose the implementation of an early warning system for the short-term forecast of such explosions, based on the real-time automatic detection of the tilt signals preceding such events.
    Description: Published
    Description: L08308
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 45
    Publication Date: 2017-04-04
    Description: Ground deformation occurring on Mount Etna from 1994 to 1995 is analyzed in this paper. This period was characterized by intense volcanic activity at the four summit craters, with frequent strombolian activity, fire fountains, and emplacement of several new lava flows. Four GPS surveys were carried out during this time, two as routinely planned each year and an additional two in 1995 to acquire more data to follow the activity at the NE Crater. The comparisons between GPS surveys are reported in terms of horizontal and vertical displacements of each station and in terms of areal dilatation and principal strain axes. During the period considered in this work, a trend of increasing areal dilatation of the volcano (at a rate of about 5 mstrain/yr) was recognized; it was briefly interrupted by a small contraction (about 2 mstrain), in the autumn of 1995, when volcanic activity at the summit craters began. In detail, the strain distribution of the network is analyzed; it allows the detection of areas showing anomalous behavior, such as the summit zone or the Pernicana fault. Inversions of the ground displacement vectors have been performed by appropriately combining numerical and analytical approaches. Results of the inversions suggest structures defining an eastward and southward sliding of the eastern and southeastern sectors of Mount Etna.
    Description: CNR-GNV "Empedocle" ESA-ESRIN project
    Description: Published
    Description: 2153
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: GPS ; Ground deformation ; modeling ; Flank instability ; Mt. Etna ; Volcano dynamics ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 46
    Publication Date: 2017-04-04
    Description: The spatial pattern of the b value of the frequency-magnitude relation has been analyzed using gridding techniques beneath Mount Etna, Italy. A regional data set of 2900 events with Md (duration magnitude) 1.5 up to 15 km depth occurring between August 1999 and December 2005 has been used. Two regions with an abnormally high b value have been found, one centered beneath the southern part of the Valle del Bove, above the 6 km below sea level (bsl) deep basement, and the other beneath the summit region 2 km bsl east of the Central Craters. We can infer that these high b value anomalies are regions of increased crack density, and/or high pore pressure, related to the presence of nearby magma storage. This interpretation is supported by all the available geophysical evidence, such as tomographic studies and geodetic deformation measurements. The data set has also been subdivided into five periods, corresponding to different phases of volcanic activity: 2001 preeruption, 2001 eruptive, 2002–2003 preeruption, 2002–2003 eruptive, and 2002–2003 posteruption. The minimum magnitude of completeness, Mc, and the b value were computed for each period. A volume of anomalously high b values can be observed in each of these periods (except for the 2002–2003 preeruption interval). This approach has allowed the detection of the transient presence of magmatic intrusions during the various periods evaluated.
    Description: Published
    Description: B12303
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: b value ; Mount Etna ; frequency-magnitude relation ; magmatic intrusions ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 47
    Publication Date: 2017-04-04
    Description: Ground deformation at Mt. Etna detected by three GPS surveys carried out in 2004, 2005, and 2006 is analyzed. The data set encompasses the 2004–2005 eruptions and foreruns those of 2006. A wide deflation of the entire volcano was detected from 2004 to 2005, accompanying the 2004–2005 eruption; conversely an evident inflation phase, from 2005 to 2006, followed this eruption and preceded the 2006 one. In both cases, the deflation-inflation cycle was accompanied by a continuous seaward motion of the eastern flank. We inverted both data sets (2004–2005 deflation and 2005–2006 inflation) using an optimization algorithm based on the Genetic Algorithm (GA) in order to detect the ground deformation sources. The wide contraction measured during the eruption reveals the drainage of a sill-shaped magma reservoir located by data inversions at a depth of about 4.5 km b.s.l. The pressurizing source modeled for the 2005–2006 time interval indicates a refilling of the shallower near-vertical plumbing system of the volcano. This could indicate a change in the geometry of the feeding system, active after the 2004–2005 eruption, with a new and shallower magma storage that could have enabled the resumption of volcanic activity that was observed at summit craters in 2006. These results improve the imaging of the plumbing system of Mt. Etna volcano.
    Description: Published
    Description: B05406
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Ground deformation ; GPS ; Genethic algorithms ; Modelong ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks
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  • 48
    Publication Date: 2017-04-04
    Description: During the effusive phase of the Stromboli 2007 eruption, the GPS and tilt stations recorded small but significant changes which, for the first time at this volcano, clearly indicated a deflation. We modeled the deflation, inferring a depressurizing vertically elongated source with centre under the volcano edifice about 2.8 km below sea level. The model, whose position is above the magma source region inferred by petrological studies, and the associated rapid deflation suggest a near free pathway for magma ascent from this source to the upper shallow conduit.
    Description: Published
    Description: L06311
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; 2007 eruption ; ground deformation ; modelling ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 49
    Publication Date: 2017-04-04
    Description: Since the last eruption in 1888-90, volcanic activity at Vulcano Island (Aeolian Archipelago, Italy) has been limited to fumarolic degassing, concentrated near the active cone of “La Fossa” crater in the northern sector of the island. During the period 1990-1996, EDM and levelling data indicate a deflation and contraction focused on the La Fossa Cone. We jointly inverted these datasets using for volume change both a spherical Mogi (1958) source and an ellipsoid as defined by Davis (1986). The best fitting source for the 1990-96 deflation is a shallow sub-vertical prolate ellipsoid positioned roughly under the crater. Our model is consistent with increased activity in a shallow hydrothermal system, supported by observations of water evaporation testified by the increase of steam emission and temperature at crater fumaroles. The fluid loss from a shallow geothermal reservoir is the most likely cause of the subsidence recorded at La Fossa Cone during the same period. This clear linkage between the deformation signals and hydrothermal activity, has important implications in the hazard assessment and monitoring of the Vulcano activity.
    Description: Published
    Description: B07402
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: modeling ; hydrothermal source ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 50
    Publication Date: 2017-04-04
    Description: Stromboli is an open conduct volcano characterized by “Strombolian” activity. This activity is the result of a “delicate” dynamic equilibrium between continuous refilling of deep volatiles exsolved from the magma batch and superficial degassing. The volatiles, reaching the surface, interact with superficial fluids modifying peripheral and summit degassing processes. In particular, the main peripheral manifestations are represented by dissolved volatiles in the basal hydrothermal aquifer, as well as structurally controlled soil degassing at the lower parts of the volcanic edifice. Summit degassing is manifested by active (explosions from the conduct) and passive degassing (plume degassing from the conduct and diffuse soil degassing). During “normal” Strombolian activity this dynamic equilibrium allows the discharge of the volatiles in the atmosphere arriving from the depth. When the deep volatile flux increases, we observe that the system reacts by first increasing the diffuse volatile discharge from the superficial system. In fact, the result is the increase of Strombolian activity (frequency and energy of explosions due to the increase of the total volatiles pressure) and the increase of the total dissolved volatiles in the hydrothermal aquifer and soils anomalous flux. During overpressure of the plumbing system paroxistic activity is necessary to maintain the dynamic pressure equilibrium, allows to maintain the dynamic equilibrium between deep and superficial volatiles. In fact, through the opening of new fractures and consecutive lava flow or by major explosions and paroxysms the system decreases the total pressure of volatiles and restores the dynamic equilibrium of the Stromboli plumbing system. On the basis of the experiences acquired during the last two eruptions (2002-2003 and 2007) we improved our geochemical monitoring network by installing new equipments for monitoring, continuously, selected fluid manifestations located on the peripheral areas. In particular, we installed two automatic equipments for measuring dissolved CO2 in the thermal wells located in the N-E side of Stromboli (Stromboli village). In this way we covered wider area of fluid degassing of Stromboli volcano to better understand the relationships between the degassing regimes of the summit and basal hydrothermal systems.
    Description: Published
    Description: San Francisco CA, USA
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: open
    Keywords: CO2 flux ; Volcano monitoring ; Stromboli ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 51
    Publication Date: 2017-04-04
    Description: We report here on the first hydrogen determinations in the volcanic gas plume of Mount Etna, in Italy, which we obtained during periodic field surveys on the volcano’s summit area with an upgraded MultiGAS. Using a specific (EZT3HYT) electrochemical sensor, we resolved H2 concentrations in the plume of 1–3 ppm above ambient (background) atmosphere and derived H2‐SO2 and H2‐H2O plume molar ratios of 0.002–0.044 (mean 0.013) and 0.0001–0.0042 (mean 0.0018), respectively. Taking the above H2‐SO2 ratios in combination with a time‐averaged SO2 flux of 1600 Gg yr−1, we evaluate that Etna contributes a time‐averaged H2 flux of ∼0.65 Gg yr−1, suggesting that the volcanogenic contribution to the global atmospheric H2 budget (70,000–100,000 Gg yr−1) is marginal. We also use our observed H2‐H2O ratios to propose that Etna’s passive plume composition is (at least partially) representative of a quenched (temperatures between 750°C and 950°C) equilibrium in the gas‐magma system, at redox conditions close to the nickel‐nickel oxide (NNO) mineral buffer. The positive dependence between H2‐SO2, H2‐H2O, and CO2‐SO2 ratios suggests that H2 is likely supplied (at least in part) by deeply rising CO2‐rich gas bubbles, fluxing through a CO2‐depleted shallow conduit magma.
    Description: Published
    Description: B10204
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: restricted
    Keywords: Hydrogen ; Mount Etna ; Open-vent volcano ; plume ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 52
    Publication Date: 2017-04-04
    Description: GPS (Global Positioning System) monitoring has been performed on Etna volcano since 1988, making this volcano one of those with the longest records of GPS data. The first order network, measured at least once every year in accurate static mode, was progressively augmented from 9 benchmarks in 1988 to ~70 benchmarks. The whole network is subdivided into seven sub-networks that are surveyed in static, quick-static or kinematic mode, according to the accuracy and density needed, with respect to the volcanic activity. This network provides key constraints to locate the deformation sources inside the volcano (reservoirs, dykes, faults) and track their evolution. Etna has proved an optimum testing ground of new surveying approaches in order to optimize geodetic fieldwork. Several methodological developments related to kinematic surveys and to the correction of tropospheric delays were made on Etna. Here, we discuss the overall picture of the entire data set up to 1999. The results show large scale displacements related to the activity of the volcano during the last twelve years. They are used to infer the location of magma reservoirs acting in this period, identifying a pressure zone beneath the western flank at a depth ranging from 2 to 9 km, several shallow intrusion following the regional NNW-SSE trend, and to quantify the eastward movement of the eastern flank of Mt. Etna, modeling two detachment surfaces beneath the eastern and southern flanks. At a local scale (e.g. in the summit areas and across the Pernicana fault), displacements are also identified and discussed.
    Description: Published
    Description: 321-341
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: reserved
    Keywords: Ground deformation ; Geodesy ; Monitoring ; Geodetic networks ; Geodetic surveys ; GPS ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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    Type: book chapter
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  • 53
    Publication Date: 2020-02-24
    Description: Socorro Island is the exposed part of an approx. 4000-m-high volcanic edifice rising from the oceanic floor to approx. 1000 m asl at the northern part of the Mathematician Ridge, Western Pacific. The volcano is active, with the most recent basaltic eruption in 1993. Moderate fumarolic activity and diffuse degassing with a total CO2 flux of approx. 20 total day)1 are concentrated in the summit region of the volcano composed of a group of rhy- olite domes. Low-temperature, boiling point, fumaroles discharge gas with high H2 (up to 20 mol% in dry gas) and CH4 (up to 4 mol%). Both carbon and He isotopic ratios and abundances correspond to those in MORB flu- ids (d13CCO2 )5&; 3He ⁄ 4He = 7.6 Ra, CO2 ⁄ 3He = (2–3) · 109, where Ra is the atmospheric ratio 3He ⁄ 4He of 1.4 · 10)6. Light hydrocarbons (CH4, C2H6, C3H8, and C4H10) are characterized by a high C1 ⁄C2+ ratio of approx. 1000. Methane is enriched in 13C (d13CCH4 from )15 to )20&) and 2H (d2H from )80 to )120&), and hydrocarbons show an inverse isotopic trend in both d13C and d2H (ethane is isotopically lighter than methane). These isotopic and concentration features of light hydrocarbons are similar to those recently discovered in fluids from ultramafic-hosted spreading ridge vents and may be related to the serpentinization processes: H2 generation and reduction of CO2 to CH4 within high-temperature zone of volcano-seawater hydrothermal system hosted in basaltic and ultramafic rocks beneath a volcano edifice. The thermodynamic analysis of this unusual composition of the Socorro fluids and the assessment of endmember compositions are complicated by the near-surface cool- ing, condensation and mixing with meteoric water.
    Description: Published
    Description: 542-555
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: open
    Keywords: Geochemistry ; isotopes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 54
    Publication Date: 2017-04-04
    Description: We present an overview of the volcanic seismicity recorded at Stromboli from January to September 2003. The data set starts few weeks after the onset of the eruption and covers most of the effusive phase and the subsequent recovery of the explosive activity. The most important variations occurred between May and July coinciding with the waning of the lava flow and the reappearance of Strombolian activity at the summit craters. All the parameters indicate that the shallow magmatic system has not undergone permanent changes during this period. The only significant variation related to the shallow conduit is the increase in volcanic tremor amplitude and the change in the spectral content of long-period events during the transition between effusive and explosive activity. A slight increase in the very-long-period (VLP) events source elevation seems to mark the rise of the magma at the end of the effusive phase. The variations in the VLP events occurrence rate are more likely to be attributed to changes in the gas flow rate and the bubble coalescence mechanism, therefore, to a deeper portion of the magmatic system. The 5 April paroxysm is associated only with a small increase of the activity in the following days.
    Description: Published
    Description: 279-286
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: reserved
    Keywords: Stromboli ; Seismological monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 55
    Publication Date: 2020-02-24
    Description: On 7 September 2008 a major ash explosion occurred from the SW summit crater of Stromboli volcano. This explosive event lasted ~2 min and consisted of three discrete eruptive pulses, forming an eruptive ash cloud ~500–600 m high and ~300 m wide, 11 rising with speed of 20–27 m s-1. The event was recorded by our camera and seismic networks, as well as by two electric stations installed at a 500 m mean distance from the SW crater. The electric signals recorded by the two stations during this event were 106 times greater than signals recorded during the persistent Strombolian activity, and the seismic trace had a bigger amplitude and a longer duration. Camera image analysis allowed us to infer that a partial obstruction took place at the SW crater three days before the explosive event, suggesting that a constriction within the upper conduit could have likely led to magma overpressure. Data analysis, combined with previous experimental investigations, revealed that the higher energy output of the ash explosion, when compared to the persistent Strombolian activity, resulted in a greater magma fragmentation and erupted mass. Integration of the different parameters allowed us to classify the event as a Vulcanian type, and electric signal analysis enabled retrieval of the total volume of erupted ash and of the amounts of the juvenile, phreatomagmatic, and lithic components.
    Description: This paper was partially supported by a research project (project INGV-DPC Paroxysm V2/03, 2007–2009) funded by Istituto Nazionale di Geofisica e Vulcanologia and by the Italian Civil Protection.
    Description: Published
    Description: B05201
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: open
    Keywords: Stromboli ; major explosions ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 56
    Publication Date: 2023-01-19
    Description: Bromine monoxide (BrO) and sulphur dioxide (SO2) abundances as a function of the distance from the source were measured by ground-based scattered-light Multi AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) in the volcanic plumes of Mt. Etna on Sicily, Italy in August-October 2004 and May 2005 and Villarica in Chile in November 2004. BrO and SO2 spatial distributions in a cross section of Mt. Etna’s plume were also determined by Imaging DOAS. We observed an increase in the BrO/SO2 ratio in the plume from below the detection limit near the vent to about 4.5 x 10-4 at 19 km (Mt. Etna) and to about 1.3 x 10-4 at 3 km (Villarica) distance, respectively. Additional attempts were undertaken to evaluate the compositions of individual vents on Mt. Etna. Furthermore, we detected the halogen species ClO and OClO. This is the first time that OClO could be detected in a volcanic plume. Using calculated thermodynamic equilibrium compositions as input data for a one–dimensional photochemical model, we could reproduce the observed BrO and SO2 vertical columns in the plume and their ratio as function of distance from the volcano as well as vertical BrO and SO2 profiles across the plume with current knowledge of multiphase halogen chemistry, but only when we assumed the existence of an ”effective source region”, where volcanic volatiles and ambient air are mixed at about 600°C (in the proportions of 60% and 40%, respectively)
    Description: Published
    Description: D06311
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Description: open
    Keywords: Chemistry ; Volcanic Plumes ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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