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  • Articles  (983)
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  • Open Access-Papers  (983)
  • 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
  • 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
  • Carbon sequestration
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  • Articles  (983)
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  • 1
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    Seismic Imaging of the Antarctic Continental Lithosphere: a Review (2006)
    Details
    Publication Date: 2020-11-17
    Description: Tomographic analysis of seismic surface waves can map upper mantle structure under the Antarctic plate with reliability and fairly good detail, making the best use of the relatively limited dataset currently available. The large-scale features of Antarctic upper mantle agree with global views of Earth structure under oceans and continents. Low seismic velocities map the hot thermal anomaly under mid-ocean ridges down to approximately 150 km, stronger and wider under faster-spreading ridges. Cold continental roots show as seismically fast material under the older part of the continent (East), while the West Antarctic Rift System has a clearly slow wave signature. The seismically imaged lithosphere has variable thickness under the craton. It appears rather regular and about 220 km thick under Dronning Maud Land, but it deepens in the region stretching below Enderby Land, Gamburtsev Mountains, to Wilkes Land, where it reaches its maximum thickness, in excess of 250 km. This variability in lithospheric thickness is analogous to what has been found under other continents. The high velocity anomaly imaging cratonic roots appears to spread out, as a cool halo, off the passive continental margins, but terminates sharply towards the West Antarctic Rift System. The fast/slow contact runs under the Transantarctic Mountains and it is particularly sharp in the Ross Embayment, where seismically slow material, imaged down to 250 km, can be interpreted as the deep-seated hot anomaly related to a mantle plume.
    Description: Research supported by Programma Nazionale di Ricerche in Antartide.
    Description: Published
    Description: reserved
    Keywords: Seismic tomography ; Antarctica ; Lithosphere ; Surface waves ; Continental Roots ; Precambrian cratons ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Mechanisms for ground-surface fracturing and incipient slope failure associated with the 2001 eruption of Mt. Etna, Italy: analysis of ephemeral field data (2008)
    Elsevier
    Details
    Publication Date: 2020-11-26
    Description: During the July^August 2001 eruption of Mt. Etna development of extensional fractures/faults and grabens accompanied magma intrusion and subsequent volcanic activity. During the first days of the eruption, we performed an analysis of attitude, displacement and propagation of fractures and faults exposed on the ground surface in two sites, Torre del Filosofo and Valle del Leone, located along the same fracture system in the region surrounding the Valle del Bove depression on the eastern flank of Mt. Etna. Fractures and faults formed as the consequence of a shallow intruding dyke system that fed the several volcanic centres developed along the fracture system. The investigated sites differ in slope attitude and in geometrical relationships between fractures and slopes. In particular, the fracture system propagated parallel to the gentle slope (67‡ dip) in the Torre del Filosofo area, and perpendicular to the steep slope (V25‡ dip) in the Valle del Leone area. In the Torre del Filosofo area, slight graben subsidence and horizontal extension of the ground surface by about 3 m were recorded. In the Valle del Leone area, extensional faulting forming a larger and deeper graben with horizontal extension of the ground surface by about 10 m was recorded. For the Valle del Leone area, we assessed a downhill dip of 14‡ for the graben master fault at the structural level beneath the graben where the fault dip shallows. These results suggest that dyke intrusion at Mount Etna, and particularly in the region surrounding the Valle del Bove depression, may be at the origin of slope failure and subsequent slumps where boundary conditions, i.e. geometry of dyke, slope dip and initial shear stress, amongst others, favour incipient failures.
    Description: Published
    Description: 281-294
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: dykes ; extensional fractures ; grabens ; slope failures ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 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::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
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    P wave seismic velocity and Vp/Vs ratio beneath the Italian peninsula from local earthquake tomography (2008)
    Elsevier
    Details
    Publication Date: 2020-11-17
    Description: We investigate the P wave velocity structure and the Vp/Vs ratio beneath the Italian peninsula down to 100 and 60 km depth respectively by seismic travel time tomography. We invert data provided by the International Seismological Centre (ISC) (1997–2005), making use of some alternative strategies for the travel time approach in a well constrained and worldwide adopted code (SIMULPS). Resolution for the different layers is discussed and sensitivity analyses are performed through test inversions to explore the resolution characteristics of the model at different spatial scales. The resulting tomographic images provide a detailed sketch of the P wave anomalies, clearly showing, among the other features, the shape of the Ivrea body in the Western Alps, the upwelling of the oceanic crust in the Ligurian Sea and the slab under the Calabrian arc. They are less informative for the Vp/Vs ratio. Nevertheless, some features are very interesting and deserve further investigation like the anomalous decrease of the Vp/Vs ratio under the Ligurian Sea or the variations of the Vp/Vs ratio calculated in the first 10 km depth of the Apenninic region with respect to the lower values of the Alpine region at the same depth. The tomographic cross sections reveal a continuous superposition of two kinds of crusts (transitional over Adriatic) all along the peninsula but do not show any slab, intended as a clear, vertical downgoing high velocity material in either the northern or central Apennines.
    Description: Published
    Description: 1-23
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Description: reserved
    Keywords: Seismic tomography ; Lithospheric structure ; Vp/Vs ratio ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    The April-May 2006 volcano-tectonic events at Stromboli volcano (Southern Italy) and their relation with the magmatic system. (2006)
    Details
    Publication Date: 2020-12-01
    Description: Between April 10th and May 22th 2006, a small seismic swarm of 5 volcano-tectonic events occurred on the volcanic island of Stromboli (Southern Italy). Two of these, having M 〉 3 and an intensity of about V-VI MCS, were clearly felt causing concern in the population. They were recorded during a period of increased explosive activity and were followed by two major explosions at the summit craters on May 22th, few hours after the last earthquake and on 16th June. The location of such events has been performed using a probabilistic approach based on the Equal Differential Time tecnique. Using this tecnique, we were able to locate all the events, showing how they cluster below the volcanic edifice at a depth of about 5÷6 km. From observed P wave polarities we determined the focal mechanisms of the 4 major events. Using earthquake scaling nlaws, we calculated the fault area and the average slip for the two major events. Finally, assuming an homogeneous half-space model we computed the isotropic stress changes below the volcano edifice. The negative stress variation over the central axis of the volcano suggests that the earthquakes were triggered by a pressurization of the magmatic system.
    Description: Published
    Description: open
    Keywords: Stromboli ; Magmatic ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 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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  • 5
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    The Broadband Seismic Network of Stromboli Volcano, Italy (2010)
    SEISMOLOGICAL SOC AMER
    Details
    Publication Date: 2020-12-07
    Description: Stromboli is a volcanic island that is part of the Aeolian arch in the Mediterranean Sea (Italy). It is one of the most active volcanoes in Europe. Its moderate, but persistent, explosive activity makes it an ideal site for studies into the seismogenic processes in volcanic areas (Auger et al. 2006; Chouet et al. 2003; Chouet et al. 2008; D’Auria and Martini 2008; Del Pezzo et al. 1992; Esposito et al. 2008; Jaupart and Vergniolle 1989; Martini et al. 2007); it also attracts a lot of tourists. In the past, this combination of tourism and volcanic activity was not considered to be dangerous, but over the past few decades, Stromboli has produced stronger explosions that have in some cases injured people visiting the summit area. Moreover, in the recent history of Stromboli, two effusive eruptions have occurred that were accompanied by dangerous phenomena such as tsunami and vulcanian explosions. The first of these effusive eruptions (on 28 December 2002) produced a lava flow on the Sciara del Fuoco side, which is the northwest flank of the island. Two days later, a landslide occurred on this flank, which resulted in the propagation of a 10-m tsunami wave around the coasts of the island. These events demonstrate that Stromboli can be dangerous, even if its activity is not very energetic. Indeed, the Sciara del Fuoco structure is a weakness zone of the volcanic edifice that fractures when the explosive activity increases, giving rise to this effusive activity (Martini et al. 2007). Moreover, during the past two effusive eruptions, vulcanian explosions were associated with the end stages of the effusive phases. These damaged the village of Ginostra and caused fires in the vegetation. For these reasons, in January 2003, the Istituto Nazionale di Geofisica e Vulcanologia (INGV; the Italian National Institute of Geophysics and Volcanology) started to install a broadband seismic network that is designed to monitor Stromboli’s volcanic activity. This nature of the activity requires broadband instruments because the eruptive processes generate signals that span a wide range of frequencies (Chouet et al. 2003; Neuberg et al. 1994). At present, the typical seismic signals that are being recorded on Stromboli are: volcanic tremors with frequencies of 1–6 Hz; explosion quakes that include components with different frequency contents, ranging from some tens of seconds up to 10 Hz; long-period (LP) earthquakes with frequencies of 1–6 Hz; volcano-tectonic (VT) earthquakes with a frequency band of 1–20 Hz; and landslide signals with frequencies of 1–10 Hz. In particular, very long period (VLP) events with frequencies of 0.02–1 Hz are associated with the Strombolian explosions and represent the lower frequency content of the explosion quakes. Furthermore, the network records regional and teleseismic events.
    Description: Published
    Description: 435-439
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Broadband Seismic Network ; Stromboli Volcano ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    Basaltic scoria textures from a zoned conduit as precursors to violent Strombolian activity (2010)
    Geological Society of America
    Details
    Publication Date: 2020-12-21
    Description: Pyroclast textures document volcanic conduit processes and may be key to hazard forecasting. Here we show that the relative abundance of mingled, variably crystallized domains in pyroclasts from scoria cone eruptions provide a record of magma ascent velocity and can be used to predict the onset of violent Strombolian activity. Scoria clasts from the Croscat Complex Scoria Cone (Spain) ubiquitously show m- to cm-sized, microlite-rich domains (MRD) intermingled with volumetrically-dominant, microlite-poor ones (MPD). Glass and bulk composition show that MRDs formed by microlite crystallization of MPDs, the former residing longer in a relatively cooler, degassed zone lining the conduit walls, the latter traveling faster in the central, hotter streamline. MPD and MRD magmas intermingled along the interface between the two velocity zones. The proportion of MPD and MRD in different tephra layers reflects the extent of the fast- and slow-flowing zones, thus reflecting the ascent velocity profile of magma during the different phases. At Croscat, the MPD/MRD volume ratio increased rapidly during the early Strombolian activity, peaked around the Strombolian to violent Strombolian shift, and then decreased smoothly irrespective of shifts in eruptive style. We suggest that magma ascent velocity escalated during the Strombolian phase due to the buoyant push of the underlying, volatile-rich magma that was about to drive the following violent Strombolian activity. Monitoring the MPD/MRD ratio of tephra during ongoing scoria cone eruptions may reveal changes in magma flow conditions and could forecast the onset of hazardous violent Strombolian activity.
    Description: Published
    Description: 439–442
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Description: open
    Keywords: basaltic ; violent strombolian ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Measuring volcanic degassing of SO2 in the lower troposphere with ASTER band ratios (2010)
    Elsevier
    Details
    Publication Date: 2020-12-07
    Description: We present a new method for measuring SO2 with the data from the ASTER (Advanced Spaceborne Thermal Emission and Reflectance radiometer) orbital sensor. The method consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. We present a sensitivity analysis for this method, and two case studies. The sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. Measurements with b25% relative precision are achieved, but only when the thermal contrast between the plume and the underlying surface is higher than 10 K. For the case studies we focused on Miyakejima and Etna, two volcanoes where SO2 is measured regularly by COSPEC or scanning DOAS. The SO2 fluxes computed from a series of ten images of Miyakejima over the period 2000–2002 is in agreement with the long term trend of measurement for this volcano. On Etna, we compared SO2 column amounts measured by ASTER with those acquired simultaneously by ground-based automated scanning DOAS. The column amounts compare quite well, providing a more rigorous validation of the method. The SO2 maps retrieved with ASTER can provide quantitative insights into the 2D structure of non-eruptive volcanic plumes, their dispersion and their progressive depletion in SO2.
    Description: R.C. was supported by a grant from F.R.I.A (Fond pour la Recherche Industrielle et Appliquée). GGS acknowledges a PhD grant funded by the project “Sviluppo di sistemi di monitoraggio” funded by Dipartimento di Protezione Civile della Regione Sicilia, INGV (Istituto Nazionale di Geofisica e Vulcanologia, sezione di Catania—Italy) and NOVAC (Network for Observation of Volcanic and Atmospheric Change) EU-funded FP6 project no. 18354. P-F. C. is research associate with FRS-FNRS and benefited from its financial support (F.4511.08).
    Description: Published
    Description: 42-54
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: remote sensing, SO2, ASTER, DOAS, Etna, Miyakejima ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    High-speed imaging of Strombolian explosions: The ejection velocity of pyroclasts (2015)
    American Geophysical Union
    Details
    Publication Date: 2020-12-14
    Description: Explosive volcanic eruptions are defined as the violent ejection of gas and hot fragments from a vent in the Earth's crust. Knowledge of ejection velocity is crucial for understanding and modeling relevant physical processes of an eruption, and yet direct measurements are still a difficult task with largely variable results. Here we apply pioneering high-speed imaging to measure the ejection velocity of pyroclasts from Strombolian explosive eruptions with an unparalleled temporal resolution. Measured supersonic velocities, up to 405 m/s, are twice higher than previously reported for such eruptions. Individual Strombolian explosions include multiple, sub-second-lasting ejection pulses characterized by an exponential decay of velocity. When fitted with an empirical model from shock-tube experiments literature, this decay allows constraining the length of the pressurized gas pockets responsible for the ejection pulses. These results directly impact eruption modeling and related hazard assessment, as well as the interpretation of geophysical signals from monitoring networks.
    Description: INGV-DPC “V2” and “Paroxysm”, FIRB-MIUR “Research and Development of New Technologies for Protection and Defense of Territory from Natural Risks”, and FP7-PEOPLE-IEF-2008 – 235328 Projects
    Description: Published
    Description: L02301
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: open
    Keywords: strombolian ; ejection velocity ; explosive eruption ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    Multisensor Satellite Monitoring of the 2011 Puyehue-Cordon Caulle Eruption (2015)
    IEEE / Institute of Electrical and Electronics Engineers Incorporated
    Details
    Publication Date: 2020-12-15
    Description: This paper shows the main outcomes of the Puyehue volcano (Chile) eruption monitoring by means of multisensor remote sensing instruments working from thermal infrared (TIR) to microwave (MW) spectral range. Thanks to the use of Synthetic Aperture Radar (SAR) and the Moderate Resolution Imaging Spectroradiometer (MODIS), the eruption evolution was observed, capturing the deformations of volcano edifice, the lava extension, as well as the information on ash and gas emitted. On the one hand, SAR Interferometry applied to ENVISAT-ASAR data allowed the estimation of the deformation occurred just before the beginning of the eruption and the subsequent deflation, with monthly sampling. On the other hand, with the combined use of the very high resolution (VHR) images taken by COSMO-SkyMed X-band SAR, and ENVISAT-ASAR ones, we were able to follow the lava deposition during the most intense phase of the eruption. Additionally, the joined exploitation of SAR and optical MODIS images allowed ash detection, also in cloudy sky conditions. Finally, the information gathered by both types of sensors allowed to highlight some volcanological features of the eruption and the relationship between surface deformation and the amount of ash and gases emitted by the volcano.
    Description: Published
    Description: 2786 - 2796
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: SAR interferometry ; Ash ; surface deformation ; lava field ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Carbon dioxide degassing from Tuscany and Northern Latium (Italy) (2008)
    Elsevier
    Details
    Publication Date: 2021-01-07
    Description: The CO2 degassing process from a large area on the Tyrrhenian side of central Italy, probably related to the input into the upper crust of mantle fluids, was investigated in detail through the geochemical study of gas emissions and groundwater. Mass-balance calculations and carbon isotopes show that over 50% of the inorganic carbon in regional groundwater is derived from a deep source highlighting gas−liquid separation processes at depth. The deep carbonate−evaporite regional aquifer acts as the main CO2 reservoir and when total pressure of the reservoir fluid exceeds hydrostatic pressure, a free gas phase separates from the parent liquid and escapes toward the surface generating gas emissions which characterise the study area. The distribution of the CO2 flux anomalies and the location of high PCO2 springs and gas emissions suggest that the storage and the expulsion of the CO2 toward the atmosphere are controlled by the geological and structural setting of the shallow crust. The average CO2 flux and the total amount of CO2 discharged by the study area were computed using surface heat flow, enthalpy and CO2 molality of the liquid phase circulating in the deep carbonate−evaporite aquifer. The results show that the CO2 flux varies from 1×104 mol y−1 km−2 to 5×107 mol y−1 km−2, with an average value of 4.8×106 mol y−1 km−2, about five times higher than the value of 1×106 mol y−1 derived by Kerrick et al. [Kerrick, D.M., McKibben, M.A., Seward, T.M., Caldeira, K., 1995. Convective hydrothermal CO2 emission from high heat flow regions. Chem. Geol. 121, 285–293] as baseline for terrestrial CO2 emissions. The total CO2 discharged from the study area is 0.9×1011 mol y−1, confirming that Earth degassing from Tyrrhenian central Italy is a globally relevant carbon source
    Description: Published
    Description: 89–102
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: Earth degassing ; carbon dioxide ; CO2 flux ; groundwater ; 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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  • 11
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    Carbon dioxide degassing and thermal energy release in the Monte Amiata volcanic-geothermal area (Italy) (2010)
    Elsevier
    Details
    Publication Date: 2021-01-07
    Description: The quaternary volcanic complex of Mount Amiata is located in southern Tuscany (Italy) and represents the most recent manifestation of the Tuscan Magmatic Province. The region is characterised by a large thermal anomaly and by the presence of numerous CO2-rich gas emissions and geothermal features, mainly located at the periphery of the volcanic complex. Two geothermal systems are located, at increasing depths, in the carbonate and metamorphic formations beneath the volcanic complex. The shallow volcanic aquifer is separated from the deep geothermal systems by a low permeability unit (Ligurian Unit). A measured CO2 discharge through soils of 1.8 109 mol a 1 shows that large amounts of CO2 move from the deep reservoir to the surface. A large range in d13CTDIC ( 21.07 to +3.65) characterises the waters circulating in the aquifers of the region and the mass and isotopic balance of TDIC allows distinguishing a discharge of 0.3 109 mol a 1 of deeply sourced CO2 in spring waters. The total natural CO2 discharge (2.1 109 mol a 1) is slightly less than minimum CO2 output estimated by an indirect method (2.8 109 mol a 1), but present-day release of 5.8 109 mol a 1 CO2 from deep geothermal wells may have reduced natural CO2 discharge. The heat transported by groundwater, computed considering the increase in temperature from the infiltration area to the discharge from springs, is of the same order of magnitude, or higher, than the regional conductive heat flow (〉200 mWm 2) and reaches extremely high values (up to 2700mWm 2) in the north-eastern part of the study area. Heat transfer occurs mainly by conductive heating in the volcanic aquifer and by uprising gas and vapor along fault zones and in those areas where low permeability cover is lacking. The comparison of CO2 flux, heat flow and geological setting shows that near surface geology and hydrogeological setting play a central role in determining CO2 degassing and heat transfer patterns.
    Description: Published
    Description: 860–875
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Carbon dioxide degassing ; Monte Amiata ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    Insights into shallow magmatic processes at Kīlauea Volcano, Hawaiʻi, from a multiyear continuous gravity time series (2017)
    American Geophysical Union
    Details
    Publication Date: 2021-02-10
    Description: Continuous gravity data collected near the summit eruptive vent at Kīlauea Volcano, Hawaiʻi, during 2011–2015 show a strong correlation with summit-area surface deformation and the level of the lava lake within the vent over periods of days to weeks, suggesting that changes in gravity reflect variations in volcanic activity. Joint analysis of gravity and lava level time series data indicates that over the entire time period studied, the average density of the lava within the upper tens to hundreds of meters of the summit eruptive vent remained low—approximately 1000–1500 kg/m^3. The ratio of gravity change (adjusted for Earth tides and instrumental drift) to lava level change measured over 15 day windows rose gradually over the course of 2011–2015, probably reflecting either (1) a small increase in the density of lava within the eruptive vent or (2) an increase in the volume of lava within the vent due to gradual vent enlargement. Superimposed on the overall time series were transient spikes of mass change associated with inflation and deflation of Kīlauea’s summit and coincident changes in lava level. The unexpectedly strong mass variations during these episodes suggest magma flux to and from the shallow magmatic system without commensurate deformation, perhaps indicating magma accumulation within, and withdrawal from, void space—a process that might not otherwise be apparent from lava level and deformation data alone. Continuous gravity data thus provide unique insights into magmatic processes, arguing for continued application of the method at other frequently active volcanoes.
    Description: Published
    Description: 5477–5492
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Kīlauea Volcano; gravity changes; lava lake; volcano monitoring ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 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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  • 13
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    Eruptive activity at Turrialba volcano (Costa Rica): Inferences from 3He/4He in fumarole gases and chemistry of the products ejected during 2014 and 2015 (2017)
    American Geophysical Union
    Details
    Publication Date: 2021-03-01
    Description: A new period of eruptive activity started at Turrialba volcano, Costa Rica, in 2010 after almost 150 years of quiescence. This activity has been characterized by sporadic explosions whose frequency clearly increased since October 2014. This study aimed to identify the mechanisms that triggered the resumption of this eruptive activity and characterize the evolution of the phenomena over the past 2 years. We integrate 3He/4He data available on fumarole gases collected in the summit area of Turrialba between 1999 and 2011 with new measurements made on samples collected between September 2014 and February 2016. The results of a petrological investigation of the products that erupted between October 2014 and May 2015 are also presented. We infer that the resumption of eruptive activity in 2010 was triggered by a replenishment of the plumbing system of Turrialba by a new batch of magma. This is supported by the increase in 3He/4He values observed since 2005 at the crater fumaroles and by comparable high values in September 2014, just before the onset of the new eruptive phase. The presence of a number of fresh and juvenile glassy shards in the erupted products increased between October 2014 and May 2015, suggesting the involvement of new magma with a composition similar to that erupted in 1864–1866. We conclude that the increase in 3He/4He at the summit fumaroles since October 2015 represents strong evidence of a new phase of magma replenishment, which implies that the level of activity remains high at the volcano.
    Description: Published
    Description: 3V. Proprietà dei magmi e dei prodotti vulcanici
    Description: 4V. Dinamica dei processi pre-eruttivi
    Description: 5V. Dinamica dei processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: Turrialba volcano ; eruptive activity ; 3He/4He ; fumarole gases ; glassy shards ; juvenile component ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 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::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 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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  • 14
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    Terminal settling velocity measurements of volcanic ash during the 2002-2003 Etna eruption by an X-band microwave rain gauge disdrometer (2005)
    AGU
    Details
    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)
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  • 15
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    Geochemistry of volcanic fluids : A special issue of the Bulletin of Volcanology in honour of Yuri A. Taran (2011)
    Springer
    Details
    Publication Date: 2021-05-17
    Description: This special issue is dedicated to Yuri Taran's outstanding contributions to gas geochemistry that began in the early 1980s with his work on deuterium and 18O compositions of geothermal waters in the Mutnovsky (Kamchatka) region and continues to this day with work on the Kamchatka volcanic volatile budget, carbon isotopes of hydrocarbons, and new insights into the geochemistry of El Chichón volcano, Chiapas. Yuri has contributed greatly to the field of volcanic gas geochemistry and was the first to recognize the distinct deuterium and oxygen isotopic composition of fumarole condensates from volcanoes in Kamchatka (Taran et al. 1987a). The shift in δD and δ18O to significantly heavier values compared to local meteoric water led Yuri to introduce the term “andesitic water” (Taran et al. 1989a, b) which has since been recognized at subduction zone volcanoes globally. This distinct isotopic composition is evidence that volcanoes release water that ultimately originates as subducted seawater and is recycled through the mantle wedge back to the earth's surface. Yuri's early work on the gas emissions from Kamchatka and Kurile Islands volcanoes also included the development and testing of gas geothermometers (Taran 1986) and investigating hydrothermal alteration using isotopic data (Taran et al. 1987b). His curiosity remained focused on the isotope systematics of volcanic gases discharging from Kamchatka and the Kuriles through the late 1980s and 1990s with publications on the gas compositions of Klyuchevskoi (Taran et al. 1991), Mutnovsky (Taran et al. 1992), Avachinsky and Koryaksky (Taran et al. 1997). Yuri was involved in the discovery of a pure and unique rhenium mineral on Kudryavy volcano (Korzhinsky et al. 1994) and provided one of the most detailed chemical studies of high temperature (up to 950°C) fumaroles to date of any volcano (Taran et al. 1995). His 1995 paper on Kudryavy remains highly cited and provides the highest quality volcanic gas data which also include trace elements from a subduction zone. Such data are crucial when we attempt to interpret lower temperature volcanic gas compositions or calculate rare metal fluxes from volcanoes worldwide. His most recent publication on Kamchatka-Kurile volcanic emissions provides a detailed analysis of the total gas flux from these volcanoes (Taran 2009).
    Description: Published
    Description: 369-371
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: Fluids Geochemistry ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 16
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    An unloading foam model to constrain Etna’s 11–13 January 2011 lava fountaining episode (2011)
    American Geophysical Union
    Details
    Publication Date: 2021-06-09
    Description: The 11–13 January 2011 eruptive episode at Etna volcano occurred after several months of increasing ash emissions from the summit craters, and was heralded by increasing SO2 output, which peaked at ∼5000 megagrams/day several hours before the start of the eruptive activity. The eruptive episode began with a phase of Strombolian activity from a pit crater on the eastern flank of the SE‐Crater. Explosions became more intense with time and eventually became transitional between Strombolian and fountaining, before moving into a lava fountaining phase. Fountaining was accompanied by lava output from the lower rim of the pit crater. Emplacement of the resulting lava flow field, as well as associated lava fountain‐ and Strombolian‐phases, was tracked using a remote sensing network comprising both thermal and visible cameras. Thermal surveys completed once the eruptive episode had ended also allowed us to reconstruct the emplacement of the lava flow field. Using a high temporal resolution geostationary satellite data we were also able to construct a detailed record of the heat flux during the fountain‐fed flow phase and its subsequent cooling. The dense rock volume of erupted lava obtained from the satellite data was 1.2 × 106 m3; this was emplaced over a period of about 6 h to give a mean output rate of ∼55 m3 s−1. By comparison, geologic data allowed us to estimate dense rock volumes of ∼0.85 × 106 m3 for the pyroclastics erupted during the lava fountain phase, and 0.84–1.7 × 106 m3 for lavas erupted during the effusive phase, resulting in a total erupted dense rock volume of 1.7–2.5 × 106 m3 and a mean output rate of 78–117 m3 s−1. The sequence of events and quantitative results presented here shed light on the shallow feeding system of the volcano.
    Description: Published
    Description: B11207
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: partially_open
    Keywords: Etna ; lava fountains ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 17
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    A year of lava fountaining at Etna: Volumes from SEVIRI (2012)
    American Geophysical Union
    Details
    Publication Date: 2021-06-09
    Description: We present a new method that uses cooling curves, apparent in high temporal resolution thermal data acquired by geostationary sensors, to estimate erupted volumes and mean output rates during short lava fountaining events. The 15 minute temporal resolution of the data allows phases of waxing and peak activity to be identified during short (150-to- 810 minute-long) events. Cooling curves, which decay over 8-to-21 hour-periods following the fountaining event, can also be identified. Application to 19 fountaining events recorded at Etna by MSG’s SEVIRI sensor between 10 January 2011 and 9 January 2012, yields a total erupted dense rock lava volume of 28 106 m3, with a maximum intensity of 227 m3 s 1 being obtained for the 12 August 2011 event. The timeaveraged output over the year was 0.9 m3 s 1, this being the same as the rate that has characterized Etna’s effusive activity for the last 40 years.
    Description: We are grateful to EUMETSAT for SEVIRI data.
    Description: Published
    Description: L06305
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: restricted
    Keywords: satellite ; lava fountains ; Etna ; erupted volume ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 18
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    Dynamics and mass balance of El Chichón crater lake, Mexico. (2012)
    Instituto de Geofisica, UNAM
    Details
    Publication Date: 2021-06-22
    Description: The mass balance of El Chichón crater lake is controlled by precipitations, evaporation and seepage through the lake bottom. The main non-meteoric source of water and Cl for the lake is a boiling spring (Soap Pool) discharging saline and neutral water with a variable flow rate from 0 to 30 kg/s inside the El Chichón crater. Variations in lake volume over time were approximately determined from digitized photographic views of the lake using an empirical relationship between depth of the lake and surface area, obtained after four bathymetric surveys. The best correlation between the observed changes in lake volume, Cl content and the measured flow rate of Soap Pool was obtained by a box-model for the Cl mass balance. Based on a trend in the Cl content of the Soap Pool water a model of a “buried” initial crater lake is proposed.
    Description: Published
    Description: 427-434
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: N/A or not JCR
    Description: open
    Keywords: Crater lake ; mass balance ; El Chichón volcano ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 19
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    Time-dependent Coulomb stress changes induced by the 2002-2003 Etna magmatic intrusions and implications on following seismic activities (2016)
    Elsevier Science Limited
    Details
    Publication Date: 2021-06-25
    Description: In this paper, the relationship between the dike-forming magmatic intrusions and the faulting process at Mount Etna is investigated in terms of Coulomb stress changes. As case study, a complete time-dependent 3-D finite element model for the 2002-2003 eruption at Mount Etna is presented. In the model, which takes into account the topography, medium heterogeneities and principal fault systems in a viscoelastic/plastic rheology, we sequentially activated three dike-forming processes and looked at the induced temporal evolution of the Coulomb stress changes, during the co-intrusive and post-intrusive periods, on Pernicana and Santa Venerina faults. We investigated where and when fault slips were encouraged or not, and consequently how earthquakes may have been triggered. Results show positive Coulomb stress changes for the Pernicana Fault in accordance to the time, location and depth of the 27th October 2002 Pernicana earthquake (Md = 3.5). The amount of Coulomb stress changes in the area of Santa Venerina Fault, as induced by dike-forming intrusions only, is instead almost negligible and, probably, not sufficient to trigger the 29th October Santa Venerina earthquake (Md = 4.4), occurred two days after the start of the eruption. The necessary Coulomb stress change value to trigger this earthquake is instead reached if we consider it as induced by the 27th October Pernicana biggest earthquake, combined with the dike-induced stresses.
    Description: MED-SUV FP7 Project (Grant number 308665)
    Description: Published
    Description: 185-196
    Description: 4V. Dinamica dei processi pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Coulomb stress changes ; Finite Element Model ; Viscoelasticity ; Earthquakes ; Mount Etna ; 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::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 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 ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
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  • 20
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    Compilation of a recent seismicity data base of the greater Alpine region from several seismological networks and preliminary 3D tomographic results (2006)
    Details
    Publication Date: 2020-10-26
    Description: Local earthquake data collected by seven national and regional seismic networks have been compiled into a travel time catalog of 32341 earthquakes for the period 1980 to 1995 in South-Central Europe. As a prerequisite, a complete and corrected station list (master station list) has been prepared according to updated information provided by every network. By simultaneous inversion of some 600 well-locatable events we obtained one-dimensional (1D) velocity propagation models for each network. Consequently, these velocity models with appropriate station corrections have been used to obtain high-quality hypocenter locations for events inside and among the station networks. For better control, merging of phase data from several networks was performed as an iterative process where at each iteration two data sets of neighbouring networks or groups of networks were merged. Particular care was taken to detect and correctly identify phase data from events common to data sets from two different networks. In case of reports of the same phase data from more than one network, the phase data from the network owning and servicing the station were used according to the master station list. The merging yielded a data set of 278007 P and 191074 S-wave travel time observations from 32341 events in the greater Alpine region. Restrictive selection (number of P-wave observations 〉7; gap 〈160 degrees) yielded a data set of about 10000 events with a total of more than 128000 P and 87000 S-wave observations well suited for local earthquake seismic tomography study. Preliminary tomographic results for South-Central Europe clearly show the topography of the crust-mantle boundary in the greater Alpine region and outline the 3D structure of the seismic Ivrea body.
    Description: JCR Journal
    Description: open
    Keywords: seismic catalogue ; tomography ; Ivrea body ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 21
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    Reference seismic velocity Earth model for Italy from local source tomography and 30 years of controlled source seismology data (2012)
    Details
    Publication Date: 2020-10-26
    Description: We present here a new high resolution regional P-wave velocity model for the lithosphere beneath the Italian region obtained by including information on the Moho topography, and integrating results from local earthquake tomography with 30 years of CSS data, applying the method of Waldhauser (1996). For the 3D moho map, we extended the crustal model, already available for the Alps by Lippitsch et al., 2003, to the Italian peninsula, Corsica, Sardinia, and Sicily. The tomographic model is obtained by inverting 166,000 Pg and Pn arrival times large part of which have been automatically picked and consistently weighted with an advanced automatic picking system (Aldersons, 2004). The resolution of the obtained velocity model is consistently higher and the grid spacing consistently smaller than in previous tomographic works targeting the same region. We are able to image the complex geometry of this part of the subduction-collision system between the Eurasian and African plates adding important details to the overview derived by the teleseismic tomography. Our results clearly show the plate boundary at Moho level from the Alps to the Southern Apennines and the Calabrian Arc in a volume unresolved in previous studies. The use of global 1D velocity models based on the flat Earth assumption is a pre-requisite to refine and interpret images and seismic responses of the earth obtained with geophysical studies (P and S tomography, surface wave tomography etc). Our model is suitable as a good starting point for a 3D velocity reference model of the crust and upper mantle beneath the Mediterranean area to be extended to the Adriatic Sea and to the Ionian Sea, with benefit for earthquakes location,teleseismic tomography, focal mechanisms and CMT
    Description: Published
    Description: Vienna
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: open
    Keywords: local earthquake tomography ; velocity model ; Italian Peninsula ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
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  • 22
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    On the transition from strombolian to fountaining activity: a thermal energy-based driver (2017)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2020-10-13
    Description: Since 1999, Mount Etna’s (Italy) South-East crater system has been characterised by episodic lava fountaining. Each episode is characterised by initial strombolian activity followed by transition to sustained fountaining to feed higheffusion rate lava flow. Here, we use thermal infrared data recorded by a permanent radiometer station to characterise the transition to sustained fountaining fed by the New South-East crater that developed on the eastern flank of the South-East crater starting from January 2011. We cover eight fountaining episodes that occurred between 2012 and 2013. We first developed a routine to characterise event waveforms apparent in the precursory, strombolian phase. This allowed extraction of a database for thermal energy and waveform shape for 1934 events. We detected between 66 and 650 events per episode, with event durations being between 4 and 55 s. In total, 1508 (78 %) of the events had short waxing phases and dominant waning phases. Event frequency increased as climax was approached. Events had energies of between 3.0× 106 and 5.8× 109 J, with rank order analysis indicating the highest possible event energy of 8.1× 109 J. To visualise the temporal evolution of retrieved parameters during the precursory phase, we applied a dimensionality reduction technique. Results show that weaker events occur during an onset period that forms a low-energy Bsink^. The transition towards fountaining occurs at 107 J, where subsequent events have a temporal trend towards the highest energies, and where sustained fountaining occurs when energies exceed 109 J. Such an energy-based framework allows researchers to track the evolution of fountaining episodes and to predict the time at which sustained fountaining will begin.
    Description: Published
    Description: 15
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Mount Etna . Strombolian events . Lava fountaining . Explosive regime transition . Radiometry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 23
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    Seismological Monitoring of Mount Vesuvius (Italy): More than a Century of Observations (2010)
    SEISMOLOGICAL SOC AMER
    Details
    Publication Date: 2020-11-30
    Description: Mt. Vesuvius (southern Italy) is one of the volcanoes that poses the greatest risk in the world because of its highly explosive eruptive style and its proximity to densely populated areas. The urbanization around Mt. Vesuvius began in ancient times, and the impact of eruptions on human activities has been severe. This is testified to by the ruins of Pompeii, which are covered by the products of the plinian eruption that took place in A.D. 79 (Sigurdsson et al. 1985), and more recently by the published reports of the eruptions that occurred from 1631 to 1944. For these reasons, Mt. Vesuvius was also one of the first volcanoes to be equipped with monitoring instruments. Pioneering instrumental observations began just before the second half of the 1800s, when the Vesuvius Observatory was founded in 1841 (Imbò 1949). At that time, Vesuvius was very active (Ricciardi 2009), and its effusive and explosive eruptions often caused damage to the surrounding areas. At the same time, it was a famous tourist attraction that drew travelers from all over the world (Gasparini and Musella 1991). Since the middle of the 1800s, at least 12 eruptions have occurred that have been superimposed on persistent intra-crater activity that has been characterized by Strombolian explosions and by the formation of small lava lakes. The last eruption occurred on 18 March 1944 and marked a change in the status of Mt. Vesuvius, as it entered a closed-conduit phase that persists today. Following this last eruption, a change occurred in the 1960s, as documented by an increase in the occurrence rate of earthquakes. Since 1972, the monitoring of Mt. Vesuvius has improved over time and become more systematic, so that there is a remarkable dataset relating to the current phase of quiescence. Over more than a century and a half of observations, many monitoring instruments have been used for Mt. Vesuvius, including early seismometers, several of which are now kept in the Museum of Volcanology of the Vesuvius Observatory. The present monitoring system is based on seismological, geodetical geodetical, and geochemical observations performed using an instrumental network that was designed on the basis of the current state of the volcano while also taking into account the likely scenario of future unrest.
    Description: Published
    Description: 625-634
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Seismological Monitoring ; Mount Vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 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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  • 24
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    150 Years of Seismological Monitoring of Mount Vesuvius (Italy). (2011)
    Details
    Publication Date: 2020-11-30
    Description: Mt. Vesuvius (southern Italy) is one of the volcanoes with the greatest risk in the World because of its highly explosive eruptive style and its proximity to densely populated areas. The urbanization around Mt. Vesuvius began in ancient times and the impact of eruptions on human activities has been very hard...
    Description: INGV,sezione di Napoli,Osservatorio Vesuviano
    Description: Published
    Description: Tenerife, Canary Islands, Spain
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: open
    Keywords: Seismological Monitoring ; Mount Vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
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    The Campi Flegrei Blind Test: Evaluating the Imaging Capability of Local Earthquake Tomography in a Volcanic Area (2013)
    Hindawi Publishing Corporation
    Details
    Publication Date: 2020-11-30
    Description: During the 1982–1984 bradyseismic crises in the Campi Flegrei area (Italy), the University of Wisconsin deployed a network of seismological stations to record local earthquakes. In order to analyse the potential of the recorded data in terms of tomographic imaging, a blind test was recently set up and carried out in the framework of a research project. A model representing a hypothetical 3D structure of the area containing the Campi Flegrei caldera was also set up, and a synthetic dataset of time arrivals was in turn computed. The synthetic dataset consists of several thousand P- and S-time arrivals, computed at about fourteen stations. The tomographic inversion was performed by four independent teams using different methods. The teams had no knowledge of either the input velocity model or the earthquake hypocenters used to create the synthetic dataset. The results obtained by the different groups were compared and analysed in light of the true model. This work provides a thorough analysis of the earthquake tomography potential of the dataset recording the seismic activity at Campi Flegrei in the 1982–1984 period. It shows that all the tested earthquake tomography methods provide reliable low-resolution images of the background velocity field of the Campi Flegrei area, but with some differences. However, none of them succeeds in detecting the hypothetical structure details (i.e. with a size smaller than about 1.5–2 km), such as a magmatic chamber 4 km deep and especially the smaller, isolated bodies, which represent possible magmatic chimneys and intrusions.
    Description: Published
    Description: Article ID 505286
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: N/A or not JCR
    Description: restricted
    Keywords: Campi Flegrei ; Tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 26
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    Tracing thermal aquifers of El Chichón volcano-hydrothermal system (México) with 87Sr/86Sr, Ca/Sr and REE (2011)
    Elsevier
    Details
    Publication Date: 2020-11-26
    Description: The volcano–hydrothermal system of El Chichón volcano, Chiapas, Mexico, is characterized by numerous thermal manifestations including an acid lake, steam vents and boiling springs in the crater and acid and neutral hot springs and steaming ground on the flanks. Previous research on major element chemistry reveals that thermal waters of El Chichón can be divided in two groups: (1) neutral waters discharging in the crater and southern slopes of the volcano with chloride content ranging from 1500 to 2200 mg/l and (2) acid-toneutral waters with Cl up to 12,000 mg/l discharging at the western slopes. Our work supports the concept that each group of waters is derived from a separate aquifer (Aq. 1 and Aq. 2). In this study we apply Sr isotopes, Ca/Sr ratios and REE abundances along with the major and trace element water chemistry in order to discriminate and characterize these two aquifers. Waters derived from Aq. 1 are characterized by 87Sr/86Sr ratios ranging from 0.70407 to 0.70419, while Sr concentrations range from 0.1 to 4 mg/l and Ca/Sr weight ratios from 90 to 180, close to average values for the erupted rocks. Waters derived from Aq. 2 have 87Sr/86Sr between 0.70531 and 0.70542, high Sr concentrations up to 80 mg/l, and Ca/Sr ratio of 17–28. Aquifer 1 is most probably shallow, composed of volcanic rocks and situated beneath the crater, within the volcano edifice. Aquifer 2 may be situated at greater depth in sedimentary rocks and by some way connected to the regional oil-gas field brines. The relative water output (l/s) from both aquifers can be estimated as Aq. 1/Aq. 2– 30. Both aquifers are not distinguishable by their REE patterns. The total concentration of REE, however, strongly depends on the acidity. All neutral waters including high-salinity waters from Aq. 2 have very low total REE concentrations (b0.6 μg/l) and are characterized by a depletion in LREE relative to El Chichón volcanic rock, while acid waters from the crater lake (Aq. 1) and acid AS springs (Aq. 2) have parallel profile with total REE concentration from 9 to 98 μg/l. The highest REE concentration (207 μg/l) is observed in slightly acid shallow cold Ca-SO4 ground waters draining fresh and old pyroclastic deposits rich in magmatic anhydrite. It is suggested that the main mechanism controlling the concentration of REE in waters of El Chichón is the acidity. As low pH results from the shallow oxidation of H2S contained in hydrothermal vapors, REE distribution in thermal waters reflects the dissolution of volcanic rocks close to the surface or lake sediments as is the case for the crater lake.
    Description: -
    Description: Published
    Description: 55-66
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: hydrogeochemistry ; geothermal systems ; Sr isotopes ; REE ; El Chichón Volcano ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 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::04.08.08. Volcanic risk
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  • 27
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    Improvement of ash plume monitoring, modeling and hazard assessment in the MED-SUV project (2015)
    Details
    Publication Date: 2020-12-21
    Description: Volcanic ash clouds produced by explosive eruptions represent a strong problem for civil aviation, road transportation and other human activities. Since Etna volcano produced in the last 35 years more the 200 explosive eruptions of small and medium size. The INGV, liable for its volcano monitoring, developed since 2006 a specific system for forecasting and monitoring Etna’s volcanic ash plumes in collaboration with several national and international institutions. Between 12 January 2011 and 31 December 2013 Etna produced forty-six basaltic lava fountains. Every paroxysm produced an eruption column ranging from a few up to eleven kilometers of height above sea level. The ash cloud contaminated the controlled airspace (CTR) of Catania and Reggio Calabria airports and caused tephra fallout on eastern Sicily sometime disrupting the operations of these airports. In order to give prompt and detailed warnings to the Aviation and Civil Protection authorities, ash plumes monitoring at Osservatorio Etneo, the INGV department in Catania, is carried out using multispectral (from visible to infrared) satellite and ground-based video-surveillance images; seismic and infrasound signals processed in real-time, a Doppler RADAR (Voldorad IIB) able to detect the eruption column in all weather conditions and a LIDAR (AMPLE) for retrieving backscattering and depolarization values of the ash clouds. Forecasting is performed running tephra dispersal models using weather forecast data, and then plotting results on maps published on a dedicated website. 24/7 Control Room operators were able to timely nform Aviation and Civil Protection operators for an effective aviation safety management. A variety of multidisciplinary activities are planned in the MED-SUV project with reference to volcanic ash observations and studies. These include: 1) physical and analogue laboratory experiments on ash dispersal and aggregation; 2) integration of satellite data (e.g. METEOSAT, MODIS) and ground- based measurements (e.g., RADAR, LIDAR) of Etna’s volcanic plumes to quantify mass eruption rate, grain-size distribution at source, and ash cloud concentration; 3) improvement of tools and automatic procedures for the short-term forecasting of volcanic ash dispersal by adopting a multi-model and multi-scenario approach; 4) development of short-term forecasting tools able to use direct measurements of the plume and ash cloud in almost real time (now-casting); 5) development of long-term probabilistic ash fallout maps at the supersite volcanoes.
    Description: Published
    Description: Vienna, Austria
    Description: 4V. Vulcani e ambiente
    Description: open
    Keywords: Ash plume monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
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    On the relevance of Born theory in global seismic tomography (2007)
    Agu
    Details
    Publication Date: 2021-01-27
    Description: Does the application of seismic Born theory, as opposed to simpler ray theory, lead to an improvement in tomographic images of the Earth? In recent publications, Montelli et al. (2004a, 2004b) and van der Hilst and de Hoop (2005) among others have expressed opposite opinions. We propose a quantitative approach to the comparison of tomographic images, which we apply to the case of surface-wave phase velocity maps derived with Born vs. ray theory.
    Description: Published
    Description: L06302
    Description: JCR Journal
    Description: reserved
    Keywords: global seismic tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 29
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    Investigation into magma degassing at Nyiragongo volcano, Democratic Republic of the Congo (2008)
    American Geophysical Union
    Details
    Publication Date: 2021-01-27
    Description: We report the first combined measurements of the composition and flux of gas emitted from Nyiragongo volcano by ground-based remote-sensing techniques. Ultraviolet spectroscopic measurements made in May/June 2005 and January 2006 indicate average SO2 emission rates of 38 kg s−1 and 23 kg s−1, respectively. Open-path Fourier transform infrared spectroscopic measurements obtained in May/June 2005, January 2006, and June 2007 indicate average molar proportions of 70, 24, 4.6, 0.87, 0.26, 0.11, and 0.0016% for H2O, CO2, SO2, CO, HCl, HF, and OCS, respectively. The composition of the plume was remarkably similar in 2005, 2006, and 2007, with little temporal variation in proportions of CO2, SO2, and CO, in particular, on the scale of seconds or days or even between the three field campaigns that span a period of 24 months. This stability persisted despite a wide range of degassing behaviors on the surface of the summit crater's lava lake (including discrete strombolian bursts and lava fountains) and variations in the SO2 emission rate. We explain these observations by a regime of steady state degassing in which bubbles nucleate and ascend in chemical equilibrium with the convecting magma. Short-term (seconds to minutes) temporal fluctuations in the SO2–HCl–HF composition were observed, and these are attributed to shallow degassing processes.
    Description: Published
    Description: Q02017
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Nyiragongo ; volcanic gas emissions ; FTIR ; DOAS ; remote sensing ; spectroscopy ; 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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  • 30
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    Theoretical study on SO2 and ash volcanic plume retrievals using ground TIR camera. Sensitivity analysis and retrieval procedure developments (2010)
    IEEE Geoscience and Remote Sensing Society
    Details
    Publication Date: 2021-01-27
    Description: In this paper, a sensitivity analysis and procedure development for volcanic-plume sulfur dioxide and ash retrievals using ground thermal infrared camera have been carried out. The semiconductor device camera, considered as a reference, has a spectral range of 8–14 μm with noise equivalent temperature difference that is better than 100 mK at 300 K. The camera will be used to monitor and assess the hazards of Mt. Etna volcano to mitigate the risk and impact of volcanic eruptions on the civil society and transports. A minimum number of filters have been selected for sulfur dioxide (SO2) and volcanic ash retrievals. The sensitivity study has been carried out to determine the SO2 and volcanic ash minimum concentration detectable by the system varying the camera geometry and the atmospheric profiles. Results show a meaningful sensitivity increase considering high instrument altitudes and low camera-elevation angles. For all geometry configurations and monthly profiles, the sensitivity limit varies between 0.5 and 2 g · m−2 for SO2 columnar abundance and between 0.02 and 1 for ash optical depth. Two procedures to detect SO2 and ash, based on the least square fit method and on the brightness temperature difference (BTD) algorithm, respectively, have also been proposed. Results show that high concentration of atmospheric water vapor columnar content significantly reduces the ash-plume effect on the BTD. A water vapor-correction procedure introduced improves the ash retrievals and the cloud discrimination in every season, considering all the camera geometries.
    Description: Published
    Description: 1619-1628
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: reserved
    Keywords: Remote sensing ; TIR-camera ; ground measurements ; sulphur dioxide ; volcanic ash ; Mt. Etna Mt. Etna volcano ; 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 ; 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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  • 31
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    Self-potential signals associated with preferential ground water flow pathways in a buried paleo-channel (2005)
    American Geophysical Union
    Details
    Publication Date: 2021-04-07
    Description: The flow of ground water in a buried permeable paleochannel can be observed at the ground surface through its self-potential signature. We apply this method to delineate the Saint-Ferréol paleo-channel of the Rhone River located in Camargue, in the South East of France. Negative potentials, 30 mV (reference taken outside the paleochannel),are associated with ground water flow in this major sand-filled channel (500 m wide). Electrical resistivity is primarily controls by the salinity of the pore water. Electrical resistivity tomography and in situ sampling show the salinity of the water inside the paleo-channel is ten times smaller by comparison with the pore water of the surrounding sediments. Combining electrical resistivity surveys, self-potential data, and a minimum of drilling information, a 3-D reconstruction of the architecture of the paleo-channel is obtained showing the usefulness of this methodology for geomorphological reconstructions in this type of coastal environment.
    Description: - Observatoire de Recherche en Environnement (ORE)
    Description: Published
    Description: L07401
    Description: partially_open
    Keywords: Self-potential ; electrical resistivity tomography ; hydrogeology ; tomography ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data
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  • 32
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    Hydrothermal fluid flow disruptions evidenced by subsurface changes in heat transfer modality: The La Fossa cone of Vulcano (Italy) case study (2016)
    Geological Society of America
    Details
    Publication Date: 2021-05-12
    Description: Detecting volcanic unrest is of primary importance for eruption forecasting, especially on volcanoes characterized by highly dangerous, and often seemingly unpredictable, phreatic or phreatomagmatic eruptions. We present a simple and innovative analysis of shallow vertical temperature profiles to depths of 70 cm. These data were recorded at La Fossa cone of Vulcano (Aeolian Islands, Italy), during an episode of increased hydrothermal and seismic activities that occurred between September and December 2009. This work involves the use of the coefficient of determination (R-2) on vertical temperature profiles in order to identify changes in conductive versus convective heat transfer modality. The increase in convective heat transfer can be related to the disruption of the hydrothermal system due to its pressurization and/or variation of ground permeability between the hydrothermal system and the surface. While raw temperature data do not evidence any significant variation during the period investigated and the classic temperature gradient is highly influenced by seasonal variations, the fluctuation of R-2 displayed striking spikes that coincided with the seismic swarm inside the volcanic edifice. Such a low-cost device associated with easy real-time data processing could constitute a very promising, yet deceptively simple, technique to monitor hydrothermal systems, in order to assess the hazard posed by high-energy eruptions for populations living close to active volcanoes.
    Description: Published
    Description: 959-962
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: seismicity ; temperature ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 33
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    Understanding stress and deformation in active volcanoes (2010)
    Elsevier
    Details
    Publication Date: 2021-06-15
    Description: No eruption, no caldera collapse, and no landslide can take place in a volcano unless its state of stress is suitable for the associated type of rock failure. The state of stress, in turn, results in deformation, and both stress and deformation depend on the mechanical properties of the rocks that constitute the volcano. Understanding stress and deformation in volcanoes is thus of fundamental importance for understanding unrest periods and for accurate forecasting volcano failure, such as may result in large-scale lateral and vertical collapses and eruptions.
    Description: Published
    Description: 1-3
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: stress, deformation, volcano tectonics, physical propertie of volcanic rocks ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 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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  • 34
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    Erratum to: Lava discharge during Etna’s January 2011 fire fountain tracked using MSG-SEVIRI (2012)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2021-06-09
    Description: In the paper by Gouhier, M., Harris, A., Calvari, S., Labazuy, P., Guéhenneux, Y., Donnadieu, F., Valade, S, entitled “Lava discharge during Etna’s January 2011 fire fountain tracked using MSG-SEVIRI” (Bull Volcanol (2012) 74:787–793, DOI 10.1007/s00445-011-0572-y), we present data from a Doppler radar (VOLDORAD 2B). This ground-based Lband radar has been monitoring the eruptive activity of the summit craters of Mt. Etna in real-time since July 2009 from a site about 3.5 km SSE of the craters. Examples of applications of this type of radar are reviewed by Donnadieu (2012) and shown on the VOLDORAD website (http://wwwobs. univbpclermont.fr/SO/televolc/voldorad/). Although designed and owned by the Observatoire de Physique du Globe in Clermont-Ferrand (OPGC), France, VOLDORAD 2B is operated jointly with the INGV-Catania (Italy) in the framework of a technical and scientific collaboration agreement between the INGV of Catania, the French CNRS and the OPGC-Université Blaise Pascal in Clermont- Ferrand. The system also utilizes a dedicated micropatch antenna designed at the University of Calabria (Boccia et al. 2010) and owned by INGV. The objective of the joint acquisition of the radar data by INGV-Catania and the OPGC is twofold: (1) to mitigate volcanic risks at Etna by better assessing the hazards arising from ash plumes and (2) to allow detailed study of volcanic activity and its environmental impact. In the paper by Gouhier et al. (2012), we failed to highlight this important collaboration between the INGV Catania and the OPGC; a cooperation essential for the past, current and future generation of such valuable data sets. Specifically we wish to acknowledge the roles of Mauro Coltelli, Michele Prestifilippo and Simona Scollo for their important input into this project, and pivotal role in setting up, and maintaining, this collaborative deployment.
    Description: Published
    Description: 1261
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: restricted
    Keywords: Etna volcano ; lava fountain ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 35
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    Seismic tomography of the Gulf of Corinth: a comparison of methods (2006)
    Details
    Publication Date: 2021-07-13
    Description: At a local scale, travel-time tomography requires a simultaneous inversion of earthquake positions and velocity structure. We applied a joint iterative inversion scheme where medium parameters and hypocenter parameters were inverted simultaneously. At each step of the inversion, rays between hypocenters and stations were traced, new partial derivatives of travel-time were estimated and scaling between parameters was performed as well. The large sparse linear system modified by the scaling was solved by the LSQR method at each iteration. We compared performances of two different forward techniques. Our first approach was a fast ray tracing based on a paraxial method to solve the two-point boundary value problem. The rays connect sources and stations in a velocity structure described by a 3D B-spline interpolation over a regular grid. The second approach is the finite-difference solution of the eikonal equation with a 3D linear interpolation over a regular grid. The partial derivatives are estimated differently depending on the interpolation method. The reconstructed images are sensitive to the spatial variation of the partial derivatives shown by synthetic examples. We aldo found that a scaling between velocity and hypocenter parameters involved in the linear system to be solved is important in recovering accurate amplitudes of anomalies. This scaling was estimated to be five through synthetic examples with the real configuration of stations and sources. We also found it necessary to scale Pand S velocities in order to recover better amplitudes of S velocity anomaly. The crustal velocity structure of a 50X50X20 km domain near Patras in the Gulf of Corinth (Greece) was recovered using microearthquake data. These data were recorded during a field experiment in 1991 where a dense network of 60 digital stations was deployed. These microearthquakes were widely distributed under the Gulf of Corinth and enabled us to perform a reliable tomography of first arrival P and S travel-times. The obtained images of this seismically active zone show a south/north asymmetry in agreement with the tectonic context. The transition to high velocity lies between 6 km and 9 km indicating a very thin crust related to the active extension regime.At a local scale, travel-time tomography requires a simultaneous inversion of earthquake positions and velocity structure. We applied a joint iterative inversion scheme where medium parameters and hypocenter parameters were inverted simultaneously. At each step of the inversion, rays between hypocenters and stations were traced, new partial derivatives of travel-time were estimated and scaling between parameters was performed as well. The large sparse linear system modified by the scaling was solved by the LSQR method at each iteration. We compared performances of two different forward techniques. Our first approach was a fast ray tracing based on a paraxial method to solve the two-point boundary value problem. The rays connect sources and stations in a velocity structure described by a 3D B-spline interpolation over a regular grid. The second approach is the finite-difference solution of the eikonal equation with a 3D linear interpolation over a regular grid. The partial derivatives are estimated differently depending on the interpolation method. The reconstructed images are sensitive to the spatial variation of the partial derivatives shown by synthetic examples. We aldo found that a scaling between velocity and hypocenter parameters involved in the linear system to be solved is important in recovering accurate amplitudes of anomalies. This scaling was estimated to be five through synthetic examples with the real configuration of stations and sources. We also found it necessary to scale Pand S velocities in order to recover better amplitudes of S velocity anomaly. The crustal velocity structure of a 50X50X20 km domain near Patras in the Gulf of Corinth (Greece) was recovered using microearthquake data. These data were recorded during a field experiment in 1991 where a dense network of 60 digital stations was deployed. These microearthquakes were widely distributed under the Gulf of Corinth and enabled us to perform a reliable tomography of first arrival P and S travel-times. The obtained images of this seismically active zone show a south/north asymmetry in agreement with the tectonic context. The transition to high velocity lies between 6 km and 9 km indicating a very thin crust related to the active extension regime.
    Description: JCR Journal
    Description: open
    Keywords: seismic tomography ; ray tracing ; eikonal equation ; inversion ; Gulf of Corinth ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 36
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    3-D density structure and geological evolution of Stromboli volcano (Aeolian Islands, Italy) inferred from land-based and sea-surface gravity data (2014)
    Elsevier Science Limited
    Details
    Publication Date: 2021-07-14
    Description: We present the first density model of Stromboli volcano (Aeolian Islands, Italy) obtained by simultaneously inverting land-based (543) and sea-surface (327) relative gravity data. Modern positioning technology, a 1 × 1 m digital elevation model, and a 15 × 15m bathymetric model made it possible to obtain a detailed 3-D density model through an iteratively reweighted smoothness-constrained least-squares inversion that explained the land-based gravity data to 0.09 mGal and the sea-surface data to 5 mGal. Our inverse formulation avoids introducing any assumptions about density magnitudes. At 125 m depth from the land surface, the inferred mean density of the island is 2380 kg m−3, with corresponding 2.5 and 97.5 percentiles of 2200 and 2530 kg m−3. This density range covers the rock densities of new and previously published samples of Paleostromboli I, Vancori, Neostromboli and San Bartolo lava flows. High-density anomalies in the central and southern part of the island can be related to two main degassing faults crossing the island (N41 and N64) that are interpreted as preferential regions of dyke intrusions. In addition, two low-density anomalies are found in the northeastern part and in the summit area of the island. These anomalies seem to be geographically related with past paroxysmal explosive phreato-magmatic events that have played important roles in the evolution of Stromboli Island by forming the Scari caldera and the Neostromboli crater, respectively. © 2014 Elsevier B.V. All rights reserved.
    Description: Published
    Description: 58–69
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Stromboli, Gravity, Inversion, Geophysics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 37
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    Shallow subduction beneath Italy: Three-dimensional images of the Adriatic-European-Tyrrhenian lithosphere system based on high-quality P wave arrival times (2010)
    American Geophysical Union
    Details
    Publication Date: 2020-10-26
    Description: This paper presents a velocity model of the Italian (central Mediterranean) lithosphere in unprecedented detail. The model is derived by inverting a set of 166,000 Pg and Pn seismic wave arrival times, restricted to the highest-quality data available. The tomographic images reveal the geometry of the subduction-collision system between the European, Adriatic, and Tyrrhenian plates, over a larger volume and with finer resolution than previous studies. We find two arcs of low-Vp anomalies running along the Alps and the Apennines, describing the collision zones of underthrusting continental lithospheres. Our results suggest that in the Apennines, a significant portion of the crust has been subducted below the mountain belt. From the velocity model we can also infer thermal softening of the crustal wedge above the subducting Adriatic plate. In the Tyrrhenian back-arc region, strong and extensive low-Vp anomalies depict upwelling asthenospheric material. The tomographic images also allow us to trace the boundary between the Adriatic and the Tyrrhenian plates at Moho depth, revealing some tears in the Adriatic-Ionian subducting lithosphere. The complex lithospheric structure described by this study is the result of a long evolution; the heterogeneities of continental margins, lithospheric underthrusting, and plate indentation have led to subduction variations, slab tears, and asthenospheric upwelling at the present day. The high-resolution model provided here greatly improves our understanding of the central Mediterranean’s structural puzzle. The results of this study can also shed light on the evolution of other regions experiencing both oceanic and continental subduction.
    Description: Published
    Description: B05305
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: open
    Keywords: lithosphere ; crust ; italy ; plates ; subduction ; europe ; seismicity ; adria ; tyrrhenian ; boundary ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 38
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    On deformation sources in volcanic areas: Modeling the Campi Flegrei (Italy) 1982–84 unrest (2011)
    Elsevier
    Details
    Publication Date: 2020-10-13
    Description: Deformation sources in volcanic areas are generally modeled in terms of pressurized tri-axial ellipsoids or pressurized cracks with simple geometrical shapes, embedded in a homogeneous half-space. However, the assumption of a particular source mechanism and the neglect of medium heterogeneities bias significantly the estimate of source parameters. A more general approach describes the deformation source in terms of a suitable moment tensor. Ratios between moment tensor eigenvalues are shown to provide a strong diagnostic tool for the physical interpretation of the deformation source and medium heterogeneities may be accounted for through 3D finite element computations. Leveling and EDM data, collected during the 1982–84 unrest episode at Campi Flegrei (Italy), are employed to retrieve the complete moment tensor according to a Bayesian inversion procedure, considering the heterogeneous elastic structure of the volcanic area. Best fitting moment tensors are found to be incompatible with any pressurized ellipsoid or crack. Taking into account the deflation of a deeper magma reservoir, which accompanies the inflation of a shallower source, data fit improves considerably but the retrieved moment tensor of the shallow source is found to be incompatible with pressurized ellipsoids, still. Looking for alternative physical models of the dislocation source, we find that the best fit moment tensor can be best interpreted in terms of a mixed mode (shear and tensile) dislocation at 5.5 km depth, striking EW and dipping by ~25°–30° to the North. Gravity changes are found to be compatible with the intrusion of ~60–70·10^6 m^3 of volatile rich magma with density ~2400 kg/m^3.
    Description: Published
    Description: 175-185
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: volcanic source ; unrest ; finite element ; inverse theory ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 39
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    Global seismic tomography and modern parallel computers (2006)
    Details
    Publication Date: 2020-11-17
    Description: A fast technological progress is providing seismic tomographers with computers of rapidly increasing speed and RAM, that are not always properly taken advantage of. Large computers with both shared-memory and distributedmemory architectures have made it possible to approach the tomographic inverse problem more accurately. For example, resolution can be quantified from the resolution matrix rather than checkerboard tests; the covariance matrix can be calculated to evaluate the propagation of errors from data to model parameters; the L-curve method can be applied to determine a range of acceptable regularization schemes. We show how these exercises can be implemented efficiently on different hardware architectures.
    Description: Published
    Description: 8T. Sismologia in tempo reale
    Description: JCR Journal
    Description: open
    Keywords: Numerical inverse theory ; seismology ; global tomography ; seismic resolution ; Earth’s mantle ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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    Monitoring of fumarole discharge and CO2 soil degassing in the Azores: contribution to volcanic surveillance and public health risk assessment (2006)
    INGV
    Details
    Publication Date: 2020-11-12
    Description: Fluid geochemistry monitoring in the Azores involves the regular sampling and analysis of gas discharges from fumaroles and measurements of CO2 diffuse soil gas emissions. Main degassing areas under monitoring are associated with hydrothermal systems of active central volcanoes in S. Miguel, Terceira and Graciosa islands. Fumarole discharge analysis since 1991 show that apart from steam these gas emissions are CO2 dominated with H2S, H2, CH4 and N2 in minor amounts. Mapping of CO2 diffuse soil emissions in S. Miguel Island lead to the conclusion that some inhabited areas are located within hazard-zones. At Furnas village, inside Furnas volcano caldera, about 62% of the 896 houses are within the CO2 anomaly, 5% being in areas of moderate to high risk. At Ribeira Seca, on the north flank of Fogo volcano, few family houses were evacuated when CO2 concentrations in the air reached 8 mol%. To assess and analyse the CO2 soil flux emissions, continuous monitoring stations were installed in S. Miguel (2), Terceira and Graciosa islands. The statistical analysis of the data showed that some meteorological parameters influence the CO2 flux. The average of CO2 flux in S. Miguel stations ranges from 250 g/m2/d at Furnas volcano to 530 g/m2/d at Fogo volcano. At Terceira Island it is about 330 g/m2/d and at Graciosa 4400 g/m2/d.
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: volcanology ; geochemistry ; soil degassing ; monitoring ; risk ; 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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    Installazione di una sonda tipo “barasol” a Dagala (Etna) per la misura continua del flusso di radon dal suolo (13 Ottobre 2006) (2007)
    Details
    Publication Date: 2020-11-23
    Description: L’Unità Funzionale Vulcanologia e Geochimica della Sezione di Catania dell’INGV sta sviluppando una nuova tecnologia che permette il monitoraggio in continuo del Radon, un gas che cambia la sua concentrazione in dipendenza del flusso di gas dal suolo. Visto che il tasso di emissione di radon dal suolo è dipendente dalla dinamica sia del magma che delle faglie, si tratta di un parametro che ha una forte potenzialità per la sorveglianza dei vulcani. Per tale motivo l’INGV, nell’ambito della Convenzione 2004-2005 con il Dipartimento della Protezione Civile, ha finanziato un progetto mirato proprio allo sviluppo tecnologico e scientifico di questo tipo di ricerca (progetto V3_6/28 – Etna, coordinatori S. Gresta e P. Papale, resp. M. Neri), la cui prima fase è iniziata il 1° giugno 2005. Questa iniziale fase di lavoro si è concretizzata con l’installazione di una prima sonda tipo “barasol” per la misura continua dell’attività di radon nel suolo presso Torre del Filosofo. Una seconda sonda, acquistata con fondi della Sezione Roma 1 dell’INGV (resp. F. Quattrocchi), è stata installata nei pressi del piano di faglia della Pernicana (quota ~1500 m s.l.m.). Una terza sonda, acquistata con fondi della Sezione Catania dell’INGV, è stata installata nei pressi di Dagala. La presente nota descrive quest’ultima installazione.
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Unpublished
    Description: open
    Keywords: NONE ; 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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  • 42
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    A reappraisal of shear wave splitting parameters from Italian active volcanic areas through a semiautomatic algorithm (2008)
    Springer Netherlands
    Details
    Publication Date: 2020-11-17
    Description: Shear wave splitting parameters represent a useful tool to detail the stress changes occurring in volcanic environments before impending eruptions. In the present paper, we display the parameter estimates obtained through implementation of a semiautomatic algorithm applied to all useful datasets of the following Italian active volcanic areas:Mt. Vesuvius,Campi Flegrei, and Mt. Etna. Most of these datasets have been the object of several studies (Bianco et al., Annali di Geofisica, XXXXIX 2:429–443, 1996, J Volcanol Geotherm Res 82:199–218, 1998a, Geophys Res Lett 25(10):1545–1548, 1998b, Phys Chem Earth 24:977–983, 1999, J Volcanol Geotherm Res 133:229–246, 2004, Geophys J Int 167(2):959–967, 2006; Del Pezzo et al., Bull Seismol Soc Am 94(2):439–452, 2004). Applying the semiautomatic algorithm, we confirmed the results obtained in previous studies, so we do not discuss in much detail each of our findings but give a general overview of the anisotropic features of the investigated Italian volcanoes. In order to make a comparison among the different volcanic areas, we present our results in terms of the main direction of the fast polarization (ϕ) and percentage of shear wave anisotropy (ξ )
    Description: Published
    Description: 253–266
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Description: reserved
    Keywords: Shear wave splitting parameters ; Temporal variations ; Volcano seismology ; Semiautomatic techniques ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
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  • 43
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    PLINIO: an interactive web interface for seismic monitoring of Neapolitan volcanoes (2008)
    INGV
    Details
    Publication Date: 2020-11-30
    Description: Seismic monitoring of active volcanoes has different and sometimes contrasting requirements. The peculiar features of volcanic seismicity makes an interactive system more complex than required for typical seismic monitoring. Intense seismic swarms of small magnitude earthquakes need a rapid but consistent processing for tracking in real time the evolution of an ongoing volcanic unrest. At the same time a comparison with the past record for detecting patterns still observed or anomalous behaviours is needed. Furthermore a correlation between different parameters as event magnitude and depth, event occurrence rate and volcanic tremor amplitude may be required. Finally, a rapid exchange of information among scientists located worldwide can be important for drawing conclusions about the evolution of a crisis. The first task can be fullfilled by an automatic seismic processing system, followed by a manual revision from expert seismologists. The second and the third can be simply accomplished storing the results of the processing in relational databases, that very well suited for such applications. The last task can be simply achieved by making the dataset accessible on-line thour a web server, in a friendly and interactive way. On the basis of the experience matured on the automatic seismic monitoring system of Stromboli ([2]) the research team of Monitoring Centre of I.N.G.V. “Osservatorio Vesuviano” started developing a similar software infrastructure for the monitoring of Neapolitan volcanoes. The existing databases: GeoVes, with supervised analysis, and Web Based Seismological Monitoring (WBSM) system, with automatic location, have been joined into a single friendly graphical interface aimed at improving the data accesibility and efficiency of the monitoring system.
    Description: Published
    Description: 363-374
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 5.9. TTC - Sistema web
    Description: open
    Keywords: plinio ; Neapolitan volcanoes ; web interface ; seismic monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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    Type: book chapter
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  • 44
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    Recent tectonic reorganization of the Nubia-Eurasia convergent 2boundary heading for the closure of the western Mediterranean (2011)
    Société Géologique de France
    Details
    Publication Date: 2020-11-26
    Description: : In the western Mediterranean area, after a long period (late Paleogene-Neogene) of Nubian northward subduction beneath Eurasia, subduction is almost ceased as well as convergence accommodation in the subduction zone. With the progression of Nubia-Eurasia convergence, a tectonic reorganization is therefore necessary to accommodate future contraction. Previously-published tectonic, seismological, geodetic, tomographic, and seismic reflection data (integrated by some new GPS velocity data) are reviewed to understand the reorganization of the convergent boundary in the western Mediterranean. Between northern Morocco, to the west, and northern Sicily, to the east, contractional deformation has shifted from the former subduction zone to the margins of the two backarc oceanic basins (Algerian-Liguro-Provençal and Tyrrhenian basins) and it is now active in the south-Tyrrhenian (northern Sicily), northern Liguro-Provençal, Algerian, and Alboran (partly) margins. Compression and basin inversion has propagated in a scissor-like manner from the Alboran (c. 8 Ma) to the Tyrrhenian (younger than c. 2 Ma) basins following a similar propagation of the subduction cessation and slab breakoff, i.e., older to the west and younger to the east. It follows that basin inversion is rather advanced in the Algerian margin, where a new southward subduction seems to be in its very infant stage, while it has still to properly start in the Tyrrhenian margin, where contraction has resumed at the rear of the fold-thrust belt and may soon invert the Marsili oceanic basin. GPS-derived strain rates higher in the Tyrrhenian margin than in the Algerian boundary suggest that this latter manner of contraction accommodation (contraction resumption at the rear of the orogenic wedge) is more efficient than subduction inception and basin inversion along newly-generated reverse faults (Algeria), but the differential strain rates may also be explained with the heterogeneous distribution of GPS stations. Part of the contractional deformation may have shifted toward the north in the Liguro-Provençal basin possibly because of its weak rheological properties compared with the area between Tunisia and Sardinia, where no oceanic crust occurs and seismic deformation is absent or limited compared with the adjacent strands of the Nubia-Eurasia boundary. The tectonic reorganization of the Nubia-Eurasia boundary in the study area is still strongly controlled by the inherited tectonic fabric and rheological attributes, which are both discontinuous and non-cylindrical along the boundary. These features prevent, at present, the development of long and continuous thrust faults. In an extreme and approximate synthesis, the evolution of the western Mediterranean is inferred as being similar to a Wilson Cycle in the following main steps: (1) northward Nubian subduction with Mediterranean backarc extension (since ~35 Ma); (2) progressive cessation, from west to east, of Nubian main subduction (since ~15 Ma); (3) progressive compression, from west to east, in the former backarc domain and consequent basin inversion (since ~8-10 Ma); (4) possible future subduction of former backarc basins.
    Description: Published
    Description: 279-303
    Description: 1.9. Rete GPS nazionale
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: open
    Keywords: western Mediterranean ; convergent boundary ; tectonic reorganization ; subduction, ; backarc basin ; basin inversion ; 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::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 45
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    Rete gravimetrica di precisione all'isola di Pantelleria. Monografie delle stazioni. Situazione al mese di luglio 2011 (2012)
    Details
    Publication Date: 2020-11-10
    Description: Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Napoli Osservatorio Vesuviano
    Description: Published
    Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Description: open
    Keywords: Rete gravimetrica ; Schede monografiche ; Misure gravimetriche ; Pantelleria ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 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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  • 46
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    Crustal fracturing and presence of fluid as revealed by seismic anisotropy: Case histories from seismogenic areas in the Apennines (Italy) (2012)
    Details
    Publication Date: 2020-12-17
    Description: An automatic analysis code, Anisomat+, was developed, tested and improved to calculate anisotropic parameters: fast polarization direction and delay time. Anisomat+ was applied on data coming from three zones of the Apennines in Italy. For each area, anisotropic parameters have been interpreted to determine the fracture and stress field taking into account the geological and structural settings. It was recognized that average of fast directions are oriented NW-SE at all sites, in agreement with the orientation of maximum horizontal stress and also with the strike of the main fault structures. The mean values of normalized delay time range from 0.005 s/km to 0.007 s/km and to 0.009 s/km, respectively for L'Aquila region, Alto Tiberina Fault area and Val D'Agri basin, suggesting a 3-4% of crustal anisotropy. Moreover, for each area, the spatial distributions of anisotropic parameters are examined, for L’Aquila 2009 seismic sequence also their temporal distribution is discussed.
    Description: Published
    Description: 417-433
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: open
    Keywords: seismic anisotropy ; Earth Crust ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 47
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    2D seismic tomography of Somma- Vesuvius. Description of the experiment and preliminary results. (2006)
    Details
    Publication Date: 2020-12-03
    Description: A multidisciplinary project for the investigation of Mt. Vesuvius Structure was started in 1993. The core of the project is represented by a high resolution seismic tomography study by using controlled and natura1 sources. The main research objective is to investigate the feeding system of the vo1cano and to retrieve details of the upper crustal structure in the area. A first 2D using seismic experiment was performed in May 1994, with the aim of studing the feasibility of lIsing tomographic techniques for exploring the vo1cano interiors. Particularly, this experiment was designed to obtain information on the optimal sources-receivers configuration and on the depth extension of the volume sampled by shot-generated seismic waves. 66 three-component seismic stations and 16 single-component analogue instruments were installed by several Italian and French groups to record signals generated by three on-land, underground explosions. Sources and geophones were deployed along a 30-km NW-SE profile passing through the volcano crater. Receivers were placed at an average spacing of 250 m in the middle of the recording line and at 500 m outside. The arrival time data base was complemented by first P and S readings of micro earthquakes which occurred in the recent past within the volcano. The first arrival data set was preliminary used to determine the shallow structure of the volcano by applying Thurber's (1983) tomographic inversion technique. This analysis shows evidence for a high-velocity body which extends vertically from about 400 m below the crater down to at least 3000 m and for a shallow 300-500 m thick low-velocity cover which borders the edifice. Data from the distant shot show evidence for arrivals of deep reflected/converted phases and provide information on the deeper structure under the volcano. The results from the interpretation of 2D data are used for planning a 3D tomographic survey which will be cauied out in 1996.
    Description: JCR Journal
    Description: open
    Keywords: Vesuvius ; tomography ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 48
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    Modeling of CO2 circulation in the Colli Albani area (2010)
    IACEI | Geological Society of London
    Details
    Publication Date: 2020-12-21
    Description: The Colli Albani is a quiescent volcano located nearby the city of Roma, characterised by the presence of an active geothermal system, periodic seismic swarms and intense diffuse degassing. Several accidents, some of which lethal, have occurred in recent years associated to episodes of more intense releases and outbursts of volcanic gases, dominantly CO2 and H2S. Gas emissions are presently the most hazardous phenomenon for the highly populated Colli Albani area, along with the potential occurrence of seismic activity. This chapter presents the numerical modeling of heat and fluid circulation applied to study the mechanisms which control the diffuse degassing at Colli Albani volcano. Multi-phase and multi-component simulations were carried out using the TOUGH2 geothermal simulator in a realistic geological context, which includes all available information on the stratigraphy and structure of the Colli Albani substrate, along with data on the total gas flux, the local geothermal gradient, the local hydrogeology, and the thermal characteristics of the rocks. The geothermal reservoir at Colli Albani is hosted by the 2-3000 m thick Mesozoic-Cenozoic carbonatic succession capped by Pliocene clays which act as aquiclude and are few hundreds to over 1000m thick, in turned covered by continental sedimentary and volcanic deposits, which host the shallow hydrogeological system. Numerical simulations evaluate the effects associated with the thickness of the carbonatic basement and its cap rock; the role of CO2 supply rate at depth; and the influence of permeable channelways through the cap rocks. Numerical simulations show that thickness of the geothermal reservoir hosted by the carbonatic basement and of its impervious cover control the vigor of the convection, the extent and depth (and hence temperature) of the lateral recharge area, and the distribution of the carbon dioxide within the system. This result suggests that the temperature distribution and diffuse degassing at surface do not simply reflect the characteristics of the heat and fluid source at depth, but also the specific structure and hydrological properties of the site where they are measured.
    Description: Submitted
    Description: 311-329
    Description: 4V. Processi pre-eruttivi
    Description: open
    Keywords: Colli Albani ; degassing ; modeling ; rock properties ; 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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    Synthetic Aperture Radar (SAR) Doppler Anomaly Detected During the 2010 Merapi (Java, Indonesia) Eruption (2015)
    Details
    Publication Date: 2020-12-15
    Description: In this letter, we report the presence of a localized Doppler anomaly occurring during the focusing of a Radarsat-2 data set acquired on the Merapi volcano (Indonesia) during the devastating 2010 eruption. The Doppler anomaly is manifested as ∼3-km-wide bull’s-eye-shaped azimuth pixel shifts between two subaperture images. The Doppler anomaly is centered on the summit-south flank of the Merapi volcano. The pixel shifts reach up to 11.6 m. Since the Merapi volcano was undergoing a large eruption during the data acquisition, it is possible that there is a volcano-related phenomenon that has delayed the radar signal so much to create measurable pixel offsets within a single synthetic aperture radar (SAR) data set, similar, but more extensive, to the signal generated by targets motions; similar, but less extensive, to the signal generated by ionospheric perturbations. It is known that the SAR signal is delayed as it passes through heterogeneous layers of the atmosphere, but this delay typically affects the SAR signal to a fraction of the phase cycle or few centimeters depending on the radar wavelength employed by the system. We investigate the source of this anomalous metric signal; we review the theoretical basis of SAR image focusing, and we try to provide a consistent physical framework to our observations. Our results are compatible with the SAR signal being perturbed during the actual process of image focusing by the presence of a contrasting medium located approximately between 6- and 12.5-km altitude, which we propose being associated with the presence of volcanic ash plume.
    Description: Published
    Description: 1319 - 1323
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: SAR ; ash ; doppler anomaly ; 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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  • 50
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    Conclusion: recommendations and findings of the RED SEED working group (2016)
    The Geological Society of London
    Details
    Publication Date: 2021-01-27
    Description: RED SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modelling and response communities with experience in tracking volcanic effusive events. The group first met during a three day-long workshop held in Clermont Ferrand (France) between 28 and 30 May 2013. During each day, presentations were given reviewing the state of the art in terms of (a) volcano hot spot detection and parameterization, (b) operational satellite-based hot spot detection systems, (c) lava flow modelling and (d) response protocols during effusive crises. At the end of each pre- sentation set, the four groups retreated to discuss and report on requirements for a truly integrated and operational response that satisfactorily combines remote sensors, modellers and responders during an effusive crisis. The results of collating the final reports, and follow-up discussions that have been on-going since the workshop, are given here. We can reduce our discussions to four main findings. (1) Hot spot detection tools are operational and capable of providing effusive erup- tion onset notice within 15 min. (2) Spectral radiance metrics can also be provided with high degrees of confidence. However, if we are to achieve a truly global system, more local receiving stations need to be installed with hot spot detection and data processing modules running on-site and in real time. (3) Models are operational, but need real-time input of reliable time-averaged discharge rate data and regular updates of digital elevation models if they are to be effective; the latter can be provided by the radar/photogrammetry community. (4) Information needs to be provided in an agreed and standard format following an ensemble approach and using models that have been validated and recognized as trustworthy by the responding authorities. All of this requires a sophisticated and centralized data collection, distribution and reporting hub that is based on a philosophy of joint ownership and mutual trust. While the next chapter carries out an exercise to explore the viability of the last point, the detailed recommendations behind these findings are detailed here.
    Description: Published
    Description: 1-82
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: restricted
    Keywords: effusive eruptions ; volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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    Viscous plugging can enhance and modulate explosivity of strombolian eruptions (2015)
    Elsevier Science Limited
    Details
    Publication Date: 2021-03-01
    Description: Strombolian activity is common in low-viscosity volcanism. It is characterised by quasi-periodic, short-lived explosions, which, whilst typically weak, may vary greatly in magnitude. The current paradigm for a strombolian volcanic eruption postulates a large gas bubble (slug) bursting explosively after ascending a conduit filled with low-viscosity magma. However, recent studies of pyroclast textures suggest the formation of a region of cooler, degassed, more-viscous magma at the top of the conduit is a common feature of strombolian eruptions. Following the hypothesis that such a rheological impedance could act as a ‘viscous plug’, which modifies and complicates gas escape processes, we conduct the first experimental investigation of this scenario. We find that: 1) the presence of a viscous plug enhances slug burst vigour; 2) experiments that include a viscous plug reproduce, and offer an explanation for, key phenomena observed in natural strombolian eruptions; 3) the presence and extent of the plug must be considered for the interpretation of infrasonic measurements of strombolian eruptions. Our scaled analogue experiments show that, as the gas slug expands on ascent, it forces the underlying low-viscosity liquid into the plug, creating a low-viscosity channel within a high-viscosity annulus. The slug's diameter and ascent rate change as it enters the channel, generating instabilities and increasing slug overpressure. When the slug reaches the surface, a more energetic burst process is observed than would be the case for a slug rising through the low-viscosity liquid alone. Fluid-dynamic instabilities cause low and high viscosity magma analogues to intermingle, and cause the burst to become pulsatory. The observed phenomena are reproduced by numerical fluid dynamic simulations at the volcanic scale, and provide a plausible explanation for pulsations, and the ejection of mingled pyroclasts, observed at Stromboli and elsewhere.
    Description: European Union’s Seventh Framework Programme (FP7/2007–2013) project NEMOH, REA grant agreement No. 289976
    Description: Published
    Description: 210-218
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: analogue modeling ; strombolian explosions ; plugged vents ; volcano acoustic ; volcano infrasonic ; slug bursting ; Taylor bubble ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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 ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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    Chemical evolution of thermal waters and changes in the hydrothermal system of Papandayan volcano (West Java, Indonesia) after the November 2002 eruption (2008)
    Elsevier
    Details
    Publication Date: 2021-05-17
    Description: Papandayan is a stratovolcano situated in West Java, Indonesia. Since the last magmatic eruption in 1772,only few hydrothermal explosions have occurred. An explosive eruption occurred in November 2002 and ejected ash and altered rocks. The altered rocks show that an advanced argillic alteration took place in the hydrothermal system by interaction between acid fluids and rocks. Four zones of alteration have been defined and are limited in extension and shape along faults or across permeable structures at different levels beneath the active crater of the volcano. At the present time, the activity is centered in the northeast crater with discharge of low temperature fumaroles and acid hot springs. Two types of acid fluids are emitted in the crater of Papandayan volcano: (1) acid sulfate-chloride waters with pH between 1.6 and 4.6 and (2) acid sulfate waters with pH between 1.2 and 2.5. The water samples collected after the eruption on January 2003 reveal an increase in the SO4/Cl and Mg/Cl ratios. This evolution is likely explained by an increase in the neutralization of acid fluids and tends to show that water–rock interactions were more significant after the eruption. The evolution in the chemistry observed since 2003 is the consequence of the opening of new fractures at depth where unaltered (or less altered) volcanic rocks were in contact with the ascending acid waters. The high δ34S values (9–17‰) observed in acid sulfatechloride waters before the November 2002 eruption suggest that a significant fraction of dissolved sulfates was formed by the disproportionation of magmatic SO2. On the other hand, the low δ34S (−0.3–7‰) observed in hot spring waters sampled after the eruption suggest that the hydrothermal contribution (i.e. the surficial oxidation of hydrogen sulfide) has increased.
    Description: Published
    Description: 276-286
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: Papandayan volcano ; Indonesia ; phreatic eruption ; hydrothermal system ; fluid geochemistry ; advanced argillic alteration ; gas geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 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)
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    First-time lidar measurement of water vapor flux in a volcanic plume (2011)
    Elsevier
    Details
    Publication Date: 2021-05-11
    Description: The CO2 laser-based lidar ATLAS has been used to study the Stromboli volcano plume. ATLAS measured water vapor concentration in cross-sections of the plume and wind speed at the crater. Water vapor concentration and wind speed were retrieved by differential absorption lidar and correlation technique, respectively. Lidar returns were obtained up to a range of 3 km. The spatial resolution was 15 mand the temporal resolution was 20 s. By combining these measurements, the water vapor flux in the Stromboli volcano plume was found. To our knowledge, it is the first time that lidar retrieves water vapor concentrations in a volcanic plume.
    Description: Published
    Description: 1295–1298
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: reserved
    Keywords: Lidar ; Volcanic plume ; DIAL ; Water vapor ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 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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    Dynamics of mild strombolian activity on Mt. Etna (2015)
    Elsevier Science Limited
    Details
    Publication Date: 2021-05-12
    Description: Here we report the first measurements of gas masses released during a rare period of strombolian activity at the Bocca Nuova crater, Mt. Etna, Sicily. UV camera data acquired for 195 events over an ≈27 minute period (27th July 2012) indicate erupted SO2 masses ranging from ≈0.1 to ≈14 kg per event, with corresponding total gas masses of ≈0.1 to 74 kg. Thus, the activity was characterised by more frequent and smaller events than typically associated with strombolian activity on volcanoes such as Stromboli. Events releasing larger measured gas masses were followed by relatively long repose periods before the following burst, a feature not previously reported on from gas measurement data. If we assume that gas transport within the magma can be represented by a train of rising gas pockets or slugs, then the high frequency of events indicates that these slugs must have been in close proximity. In this case the longer repose durations associated with the larger slugs would be consistent with interactions between adjacent slugs leading to coalescence, a process expedited close to the surface by rapid slug expansion. We apply basic modelling considerations to the measured gas masses in order to investigate potential slug characteristics governing the observed activity.We also cross correlated the acquired gas fluxes with contemporaneously obtained seismic data but found no relationship between the series in line with the mild form of manifest explosivity.
    Description: Published
    Description: 103–111
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: open
    Keywords: Mild strombolian activity ; Ultra-violet imaging ; Volcanic gas measurements ; Slug dynamics ; 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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    Anomalous gas emission offshore from Panarea Island (Aeolian Arc, Italy) (2012)
    Details
    Publication Date: 2021-06-15
    Description: Panarea Island is located in the eastern sector of the Aeolian arc at only 20 km from the active volcano of Stromboli. Its recentmost volcanic products date back to about 50 ka but a probable submarine eruption occurred there in 126 B.C. Near to volcanic islets 3 km E of Panarea, on 3 November 2002 an impressive submarine gas emission began from several points at a depth 8-20 m. The strongest gas emission, with jet velocity of 1 m/s, occurred from a small depression, possibly produced by a weak submarine phreatic explosion. Most of the gas was emitted from NE-SW trending fissures, whose direction matches with the main tectonic lineament of the Panarea- Stromboli sector. Only a very weak local seismicity was recorded. Gas was sampled and the physico-chemical characteristics of the seawater (T, pH, Eh, dissolved O2,) were measured in two campaigns carried out in November and in December. Gas mostly consists of CO2 (95-98.2 vol % ) and H2S (0.7-2%). Compared with previous chemical data on the submarine fumaroles of the same area, the 2002 emission is characterized by a marked increase of H2 and a decrease of the CH4/CO ratio. These data indicate the presence of high-temperature components with a likely magmatic provenance raised from a pressurized system through newly opened fractures. The sea water was chemically modified over a wide area, as indicated by the low pH and Eh values. In the first months of 2003 the gas emission started to decline, but it was still clearly visible four months after its beginning. This phenomenon recalled the attention on the volcanic hazard related to a possible submarine eruption near Panarea, where over 10,000 people live in the tourist season.
    Description: Published
    Description: Hilo, Hawaii - July 14-18 , 2003
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: restricted
    Keywords: Panarea ; gas emission ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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    Lava discharge during Etna's January 2011 fire fountain tracked using MSG-SEVIRI (2012)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2021-06-09
    Description: Etna's January 2011 eruption provided an excellent opportunity to test the ability of Meteosat Second Generation satellite's Spinning Enhanced Visible and InfraRed Imager (SEVIRI) sensor to track a short-lived effusive event. The presence of lava fountaining, the rapid expansion of lava flows, and the complexity of the resulting flow field make such events difficult to track from the ground. During the Etna's January 2011 eruption, we were able to use thermal data collected by SEVIRI every 15 min to generate a time series of the syn-eruptive heat flux. Lava discharge waxed over a ~1-h period to reach a peak that was first masked from the satellite view by a cold tephra plume and then was of sufficient intensity to saturate the 3.9-μm channel. Both problems made it impossible to estimate time-averaged lava discharge rates using the syn-eruptive heat flux curve. Therefore, through integration of data obtained by ground-based Doppler radar and thermal cameras, as well as ancillary satellite data (from Moderate Resolution Imaging Spectrometer and Advanced Very High Resolution Radiometer), we developed a method that allowed us to identify the point at which effusion stagnated, to allow definition of a lava cooling curve. This allowed retrieval of a lava volume of ~1.2×106 m3, which, if emitted for 5 h, was erupted at a mean output rate of ~70 m3 s−1. The lava volume estimated using the cooling curve method is found to be similar to the values inferred from field measurements.
    Description: This work was supported by the Centre National d’Etudes Spatiales (CNES-France) and CNRS-INSU.
    Description: Published
    Description: 787–793
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: restricted
    Keywords: Etna volcano ; lava flux ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Magma-derived gas influx and water-rock interactions in the volcanic aquifer of Mt. Vesuvius, Italy (2005)
    Elsevier
    Details
    Publication Date: 2021-06-25
    Description: We report in this paper a systematic investigation of the chemical and isotopic composition of groundwaters flowing in the volcanic aquifer of Mt. Vesuvius during its current phase of dormancy, including the first data on dissolved helium isotope composition and tritium content. The relevant results on dissolved He and C presented in this paper reveal that an extensive interaction between rising magmatic volatiles and groundwaters currently takes place at Vesuvius. Vesuvius groundwaters are dilute (mean TDS 2800 mg/L) hypothermal fluids (mean T 17.7°C) with a prevalent alkaline-bicarbonate composition. Calcium-bicarbonate groundwaters normally occur on the surrounding Campanian Plain, likely recharged from the Apennines. D and 18O data evidence an essentially meteoric origin of Vesuvius groundwaters, the contribution from either Tyrrhenian seawater or 18O-enriched thermal water appearing to be small or negligible. However, the dissolution of CO2-rich gases at depth promotes acid alteration and isochemical leaching of the permeable volcanic rocks, which explains the generally low pH and high total carbon content of waters. Attainment of chemical equilibrium between the rock and the weathering solutions is prevented by commonly low temperature (10 to 28°C) and acid-reducing conditions. The chemical and isotope (C and He) composition of dissolved gases highlights the magmatic origin of the gas phase feeding the aquifer. We show that although the pristine magmatic composition may vary upon gas ascent because of either dilution by a soil-atmospheric component or fractionation processes during interaction with the aquifer, both 13C/12C and 3He/4He measurements indicate the contribution of a magmatic component with a 13C 0‰ and R/Ra of 2.7, which is consistent with data from Vesuvius fumaroles and phenocryst melt inclusions in olivine phenocrysts. A main control of tectonics on gas ascent is revealed by data presented in this paper. For example, two areas of high CO2 release and enhanced rock leaching are recognized on the western (Torre del Greco) and southwestern (Torre Annunziata–Pompeii) flanks of Vesuvius, where important NE-SW and NW-SE tectonic structures are recognized. In contrast, waters flowing through the northern sector of the volcano are generally colder, less saline, and CO2 depleted, despite in some cases containing significant concentrations of magmaderived helium. The remarkable differences among the various sectors of the volcano are reconciled in a geochemical interpretative model, which is consistent with recent structural and geophysical evidences on the structure of Somma-Vesuvius volcanic complex.
    Description: -European Union, -Ministero dell’Universita’ e della Ricerca Scientifica e Tecnologica; -CNR–Gruppo Nazionale per la Vulcanologia.
    Description: Published
    Description: 963–981
    Description: partially_open
    Keywords: isotopes ; water chemistry ; dissolved gases ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.07. Radioactivity and isotopes ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 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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    Continuous SO2 flux measurements for Vulcano Island, Italy (2014)
    Istituto Nazionale di Geofisica e Vulcanologia
    Details
    Publication Date: 2021-06-07
    Description: The La Fossa cone of Vulcano Island (Aeolian Archipelago, Italy) is a closed conduit volcano. Today, Vulcano Island is characterized by sulfataric activity, with a large fumarolic field that is mainly located in the summit area. A scanning differential optical absorption spectroscopy instrument designed by the Optical Sensing Group of Chalmers University of Technology in Göteborg, Sweden, was installed in the framework of the European project "Network for Observation of Volcanic and Atmospheric Change", in March 2008. This study presents the first dataset of SO2 plume fluxes recorded for a closed volcanic system. Between 2008 and 2010, the SO2 fluxes recorded showed average values of 12 t.d—1 during the normal sulfataric activity of Vulcano Island, with one exceptional event of strong degassing that occurred between September and December, 2009, when the SO2 emissions reached up to 100 t.d—1.
    Description: Published
    Description: 301-308
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 4V. Vulcani e ambiente
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: JCR Journal
    Description: open
    Keywords: SO2 ; Differential optical absorption spectroscopy ; Vulcano Island ; Network for Observation of Volcanic and Atmospheric Change ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 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::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
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    Monitoring crater-wall collapse at active volcanoes: a study of the 12 January 2013 event at Stromboli (2016)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2021-06-22
    Description: Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied through the analysis of their deposits. In this paper, we present an analysis of the 12 January 2013 crater-wall collapse occurring at Stromboli vol- cano, investigated by means of a monitoring network com- prising visible and infrared webcams and a Ground-Based Interferometric Synthetic Aperture Radar. The network re- vealed the triggering mechanisms of the collapse, which are comparable to the events that heralded the previous effusive eruptions in 1985, 2002, 2007 and 2014. The collapse oc- curred during a period of inflation of the summit cone and was preceded by increasing explosive activity and the enlarge- ment of the crater. Weakness of the crater wall, increasing magmastatic pressure within the upper conduit induced by ascending magma and mechanical erosion caused by vent opening at the base of the crater wall and by lava fingering, are considered responsible for triggering the collapse on 12 January 2013 at Stromboli. We suggest that the combination of these factors might be a general mechanism to generate crater-wall collapse at active volcanoes.
    Description: Published
    Description: 39
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Stromboli volcano ; Remote sensing ; Visible and infrared webcam monitoring ; Ground-based radar interferometry ; Crater-wall collapse ; Volcano instability ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Tunable diode laser measurements of hydrothermal/volcanic CO2 and implications for the global CO2 budget (2015)
    Copernicus Publications
    Details
    Publication Date: 2021-06-21
    Description: Quantifying the CO2 flux sustained by lowtemperature fumarolic fields in hydrothermal/volcanic environments has remained a challenge, to date. Here, we explored the potential of a commercial infrared tunable laser unit for quantifying such fumarolic volcanic/hydrothermal CO2 fluxes. Our field tests were conducted between April 2013 and March 2014 at Nea Kameni (Santorini, Greece), Hekla and Krýsuvík (Iceland) and Vulcano (Aeolian Islands, Italy). At these sites, the tunable laser was used to measure the path-integrated CO2 mixing ratios along cross sections of the fumaroles’ atmospheric plumes. By using a tomographic post-processing routine, we then obtained, for each manifestation, the contour maps of CO2 mixing ratios in the plumes and, from their integration, the CO2 fluxes. The calculated CO2 fluxes range from low (5.7 +/- 0.9 t d-1; Krýsuvík) to moderate (524 +/-108 t d-1; La Fossa crater, Vulcano). Overall, we suggest that the cumulative CO2 contribution from weakly degassing volcanoes in the hydrothermal stage of activity may be significant at the global scale.
    Description: Published
    Description: 1209–1221
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: open
    Keywords: volcanic CO2 fluxes ; Hekla volcano ; Krýsuvík hydrothermal area ; Nea Kameni ; Vulcano island ; tunable diode lasers ; 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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    The Role Played By The Environmental Factors On Diffuse Soil Degassing At Stromboli Volcano (2011)
    Details
    Publication Date: 2021-06-30
    Description: Geochemical surveys and continuous measurements of several gas species in volcanic areas are useful to identify changes in volcanic activity as well as in deep magmatic processes. Diffuse soil degassing in volcanic areas releases high amount of gases and its monitoring monitoring can be helpful for the mitigation of risk and volcano surveillance. At Stromboli, previous surveys permitted us to recognize the zones surrounding the crater where diffuse degassing is active. Here we present the first results of the in-soil [222Rn] and CO2 flux continuous monitoring started in April 2007 in one of these zones. Measurements of the CO2 flux and in-soil 222Rn concentration have been acquired simultaneously with the main environmental parameters (soil and air temperature, atmospheric pressure, soil humidity, wind direction and velocity). A multivariate statistical analysis has been applied on the entire acquired dataset, in order to outline the role of each environmental parameter in controlling the variation of in-soil degassing. Results show the key role played by the environmental factors in the process of soil gas transfer from depth to the surface. A good correlation has been found between 222Rn and CO2 flux, confirming the role of the latter as carrier of other gas species. Our results stress the importance of the collection of environmental parameters in the geochemical monitoring aimed at the identification of the processes modulating soil diffuse degassing in volcanic areas. Furthermore, the simultaneous acquisition of several gas species can provide valuable information on the state of the volcano activity and its capability to release gas from its fracture network.
    Description: Comission of Cities and Volcanoes (CaV) of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) Agencia Española de Cooperación Internacional para el Desarrollo (AECID), Gobierno de España Ministerio de Ciencia e Innovación (MICINN), Gobierno de España Unidad Militar de Emergencias (UME), Ministerio de Defensa, Gobierno de España Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI), Gobierno de Canarias Viceconsejería de Infraestructuras y Planificación, Gobierno de Canarias Consejería de Turismo, Gobierno de Canarias Consejería de Medio Ambiente y Ordenación Territorial, Gobierno de Canarias Viceconsejería de Cultura y Deportes, Gobierno de Canarias Instituto Español de Oceanografía (IEO)Instituto Geológico y Minero de España (IGME)Instituto Geográfico Nacional (IGN)Academia Canaria de Seguridad Federación Canaria de Municipios (FECAM) Universidad de La Laguna (ULL)Instituto de Estudios Hispánicos de Canarias (IEHC) CajaCanarias
    Description: Published
    Description: Puerto de la Cruz, Tenerife, Spain
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: open
    Keywords: Stromboli volcano, CO2 flux, in-soil [222Rn] monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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    Mantle to surface degassing of alkalic magmas at Erebus volcano, Antarctica (2012)
    Elsevier Science Limited
    Details
    Publication Date: 2021-06-30
    Description: Continental intraplate volcanoes, such as Erebus volcano, Antarctica, are associated with extensional tectonics, mantle upwelling and high heat flow. Typically, erupted magmas are alkaline and rich in volatiles (especially CO2), inherited from low degrees of partial melting of mantle sources. We examine the degassing of the magmatic system at Erebus volcano using melt inclusion data and high temporal resolution open-path Fourier transform infrared (FTIR) spectroscopic measurements of gas emissions from the active lava lake. Remarkably different gas signatures are associated with passive and explosive gas emissions, representative of volatile contents and redox conditions that reveal contrasting shallow and deep degassing sources. We show that this unexpected degassing signature provides a unique probe for magma differentiation and transfer of CO2-rich oxidised fluids from the mantle to the surface, and evaluate how these processes operate in time and space. Extensive crystallisation driven by CO2 fluxing is responsible for isobaric fractionation of parental basanite magmas close to their source depth. Magma deeper than 4 kbar equilibrates under vapour-buffered conditions. At shallower depths, CO2-rich fluids accumulate and are then released either via convection-driven, open-system gas loss or as closed-system slugs that ascend and result in Strombolian eruptions in the lava lake. The open-system gases have a reduced state (below the QFM buffer) whereas the closed-system gases preserve their deep oxidised signatures (close to the NNO buffer).
    Description: Published
    Description: 261–271
    Description: JCR Journal
    Description: restricted
    Keywords: CO2 fluxing ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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    The Stromboli geophysical experiment. Preliminary report on wide angle refraction seismics and morphobathymetry of Stromboli Island (Southern Tyrrhenian Sea, Italy) based on integrated offshore-onshore data acquisition (Cruise STR06 R/V URANIA) (2007)
    Details
    Publication Date: 2021-07-14
    Description: Cruise STR06 on R/V Urania was performed in the framework of the ”INGV - DPC V2 - Monitoring and research activity at Stromboli and Panarea - Unit V2/03”, and resulted as a joint initiative between CNR (IAMC, Napoli and ISMAR, Bologna), INGV (Roma2, Osservatorio Vesuviano, Catania, Gibilmanna-CNT), University of Firenze and DPC, aiming to produce a seismic tomography of the Stromboli volcano, South Eastern Tyrrhenian Sea [Fig.1], and have insights into its 2-D structure and magma chambers. Cruise work plan was designed to extend at sea the existing Seismographic Network, complemented by several mobile stations, and to generate seismic shots by air-gun tuned array. 10 OBS were deployed around Stromboli, along the NE, SE and SW flanks of the volcano, according to (a) morphobathymetric analysis of available and newly produced DTMs, (b) modeling and (c) optimal lineaments with on-land recording stations. Seismic shots along radial and circle lines were obtained by a 4 GI-GUN 105+105 C.I. tuned array, while the absolute shot time was recorded at the resolution of ms. A request for ship time of R/V Uraniawas presented by IAMC, and a period of 7 days, including 2 day of transit was assigned to the project by CNR and scheduled for late November 2006. Cruise STR06 started in Naples 2006-11-27 and ended in Naples 2006-12-06. This paper reports the shipboard activities during the cruise STR06 on R/V Urania and some preliminary results regarding also the onshore activities carried out in order to perform the Stromboli geophysical experiment. A description of the ship, equipment and their usage is given thereinafter, along with details of the general settings, performances and some scientific and technical results.
    Description: Istituto di Scienze Marine, ISMAR-CNR, Bologna
    Description: Published
    Description: 3.6. Fisica del vulcanismo
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: open
    Keywords: tomography ; Stromboli ; air-gun ; wide angle ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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    Seismic Tomography Experiment at Italy's Stromboli Volcano (2008)
    American Geophysical Union
    Details
    Publication Date: 2021-07-14
    Description: From 25 November to 2 December 2006, the first active seismic tomography experiment at Stromboli volcano was carried out with the cooperation of four Italian research institutions. Researchers on board the R/V Urania of the Italian National Council of Research (CNR), which was equipped with a battery of four 210- cubic- inch generated injection air guns (GI guns), fired more than 1500 offshore shots along profiles and rings around the volcano.
    Description: DPC/INGV agreement 2004-2006
    Description: Published
    Description: 269-270
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.6. Fisica del vulcanismo
    Description: N/A or not JCR
    Description: reserved
    Keywords: Stromboli ; seismic tomography ; air-gun ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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    The deep structure of the Larderello-Travale geothermal field (Italy) from integrated, passive seismic investigations (2015)
    Elsevier
    Details
    Publication Date: 2021-07-14
    Description: We report the preliminary results from a project (GAPSS-Geothermal Area Passive Seismic Sources), aimed at testing the resolving capabilities of passive exploration methods on a well-known geothermal area, namely the Larderello-Travale Geothermal Field (LTGF). Located in the western part of Tuscany (Italy), LTGF is the most ancient geothermal power field of the world. GAPSS consisted of up to 20 seismic stations deployed over an area of about 50 x 50 Km. During the first 12 months of measurements, we located more than 2000 earthquakes, with a peak rate of up to 40 shocks/day. Preliminary results from analysis of these signals include: (i) analysis of Shear-Wave-Splitting from local earthquake data, from which we determined the areal distribution of the most anisotropic regions; (ii) local-earthquake travel-time tomography for both P- and S-wave velocities; (iii) telesismic receiver function aimed at determining the high-resolution (〈0.5km) S-velocity structure over the 0-20km depth range, and seismic anisotropy using the decomposition of the angular harmonics of the RF data-set; (iv) S-wave velocity profiling through inversion of the dispersive characteristics of Rayleigh waves from earthquakes recorded at regional distances. After presenting results from these different analyses, we eventually discuss their potential application to the characterisation and exploration of the investigated area.
    Description: Published
    Description: 227-234
    Description: 6T. Sismicità indotta e caratterizzazione sismica dei sistemi naturali
    Description: N/A or not JCR
    Description: restricted
    Keywords: Geothermal field; Local Earthquake Tomography; Shear Wave Splitting; Surface Wave Dispersion; Receiver Functions; Larderello- Travale geothermal field (Italy) ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 66
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    Il sistema di monitoraggio sismico dell’Osservatorio Vesuviano – INGV (2008)
    Details
    Publication Date: 2020-11-11
    Description: Obiettivo principale del monitoraggio dei vulcani attivi è individuare e misurare fenomeni che possono essere indotti dal movimento del magma in profondità. Dal punto di vista sismologico questi fenomeni possono essere sciami sismici, eventi a bassa frequenza, microtremore vulcanico ed eventi very long period (VLP). Attraverso la misura, l'analisi e la corretta interpretazione di questi fenomeni è possibile capire in anticipo se un vulcano sta evolvendo verso una ripresa dell'attività eruttiva. L'Osservatorio Vesuviano - INGV ha tra i suoi compiti istituzionali il monitoraggio del Vesuvio, dei Campi Flegrei e di Ischia che sono, come è noto, vulcani a alto rischio a causa del loro stile eruttivo prevalentemente esplosivo e della presenza nelle loro prossimità di vaste aree urbanizzate. Per effettuare il monitoraggio sismologico di dette aree l'Osservatorio Vesuviano ha sviluppato e mantiene una rete che trasmette i dati in continuo al centro di sorveglianza. La configurazione attuale della rete comprende 28 stazioni analogiche a corto periodo (1Hz) e 4 stazioni digitali a larga banda.
    Description: Published
    Description: Roma
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: open
    Keywords: Il sistema di monitoraggio sismico dell’Osservatorio Vesuviano ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 67
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    Structural features of the July–August 2001 Mount Etna eruption: evidence for a complex magma supply system (2008)
    Geological Society of London
    Details
    Publication Date: 2020-11-26
    Description: We describe the evolution of the volcanic activity and deformation patterns observed at Mount Etna during the July–August 2001 eruption. Seismicity started at 3000 m below sea level on 13 July, accompanied by moderate ground swelling. Ground deformation culminated on 16 July with the development of a NE–SW graben c. 500 m wide and c. 1 m deep in the Cisternazza area at 2600–2500 m above sea level on the southern slope of the volcano. On 17 July, the eruption started at the summit of Mount Etna from the SE Crater (central–lateral eruptive system), from which two radial, c. 30 m wide, c. 3000 m long fracture zones, associated with eruptive fissures, propagated both southward (17 July) and northeastward (20 July). On 18 July, a new vent formed at 2100 m elevation, at the southern base of the Montagnola, followed on the next day by the opening of a vent further upslope, at 2550 m (eccentric eruptive system). The eruption lasted for 3 weeks. Approximately 80% of the total lava volume was erupted from the 2100 m and the 2550 m vents. The collected structural data suggest that the Cisternazza graben developed as a passive local response of the volcanic edifice to the ascent of a north–south eccentric dyke, which eventually reached the ground surface in the Montagnola area (18–19 July). In contrast, the two narrow fracture zones radiating from the summit are interpreted as the lateral propagation, from the conduit of the SE Crater, of north–south- and NE–SW-oriented shallow dykes, 2–3 m wide. The evolution of the fracture pattern together with other volcanological data (magma ascent and effusion rate, eruptive style, petrochemical characteristics of the erupted products, and petrology of xenoliths within magma) suggest that the eccentric and central–lateral eruptions were fed by two distinct magmatic systems. Examples of eccentric activity accompanied by central–lateral events have never been described before at Etna.
    Description: Published
    Description: 531-544
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Mount Etna ; July–August 2001 Eruption ; magmas ; dykes ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 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::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 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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  • 68
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    The stress field beneath a quiescent stratovolcano: The case of Mount Vesuvius (2015)
    American Geophysical Union
    Details
    Publication Date: 2020-12-15
    Description: We have analyzed a focal mechanism data set for Mount Vesuvius, consisting of 197 focal mechanisms of events recorded from 1999 to 2012. Using different approaches and a comparison between observations and numerical models, we have determined the spatial variations in the stress field beneath the volcano. The main results highlight the presence of two seismogenic volumes characterized by markedly different stress patterns. The two volumes are separated by a layer where the seismic strain release shows a significant decrease. Previous studies postulated the existence, at about the same depth, of a ductile layer allowing the spreading of the Mount Vesuvius edifice. We interpreted the difference in the stress pattern within the two volumes as the effect of a mechanical decoupling caused by the aforementioned ductile layer. The stress pattern in the top volume is dominated by a reverse faulting style, which agrees with the hypothesis of a seismicity driven by the spreading process. This agrees also with the persistent character of the seismicity located within this volume. Conversely, the stress field determined for the deep volume is consistent with a background regional field locally perturbed by the effects of the topography and of heterogeneities in the volcanic structure. Since the seismicity of the deep volume shows an intermittent behavior and has shown to be linked to geochemical variations in the fumaroles of the volcano, we hypothesize that it results from the effect of fluid injection episodes, possibly of magmatic origin, perturbing the pore pressure within the hydrothermal system.
    Description: Published
    Description: 1181–1199
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: vesuvius ; stress inversion ; focal mechanisms ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 69
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    Lava flow hazard modeling during the 2014–2015 Fogo eruption, Cape Verde (2016)
    Details
    Publication Date: 2020-12-03
    Description: Satellite remote sensing techniques and lava flow forecasting models have been combined to enable a rapid response during effusive crises at poorly monitored volcanoes. Here we used the HOTSAT satellite thermal monitoring system and the MAGFLOW lava flow emplacement model to forecast lava flow hazards during the 2014–2015 Fogo eruption. In many ways this was one of the major effusive eruption crises of recent years, since the lava flows actually invaded populated areas. Combining satellite data and modeling allowed mapping of the probable evolution of lava flow fields while the eruption was ongoing and rapidly gaining as much relevant information as possible. HOTSAT was used to promptly analyze MODIS and SEVIRI data to output hot spot location, lava thermal flux, and effusion rate estimation. This output was used to drive the MAGFLOW simulations of lava flow paths and to continuously update flow simulations. We also show how Landsat 8 OLI and EO-1 ALI images complement the field observations for tracking the flow front position through time and adding considerable data on lava flow advancement to validate the results of numerical simulations. The integration of satellite data and modeling offers great promise in providing a unified and efficient system for global assessment and real-time response to effusive eruptions, including (i) the current state of the effusive activity, (ii) the probable evolution of the lava flow field, and (iii) the potential impact of lava flows.
    Description: Acknowledgments Thanks are due to European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) for SEVIRI data (www.eumetsat.int) and to National Aeronautics and Space Administration (NASA) for MODIS data (modis.gsfc.nasa.gov). Landsat 8 OLI and Eo-1 ALI images are courtesy of the U.S. Geological Survey (earthexplorer. usgs.gov). We are grateful to the Copernicus emergency management service (emergency.copernicus.eu/ mapping/list-of-components/EMSR111) for mapping the actual lava flow field by Cosmo-SkyMed and Pleiades images. We thank the Cartográfica de Canarias, S.A. (www.grafcan.es) for making the Digital Elevation Model of Fogo Island available. HOTSAT and MAGFLOW were developed in the frame of the TecnoLab, the Laboratory for the Technological Advance in Volcano Geophysics, organized by INGV-CT and UNICT (Italy).
    Description: Published
    Description: 2290–2303
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Fogo eruption ; lava flow hazard ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 70
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    Real-time monitoring and massive inversion of source parameters of very long period seismic signals:An application to Stromboli Volcano, Italy. (2007)
    AGU
    Details
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 71
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    Movements of the Sciara del Fuoco (2012)
    AGU
    Details
    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)
    Type: book chapter
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  • 72
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    How a complex basaltic volcanic system works: constraints from integrating seismic, geodetic and petrological data at Mt. Etna volcano during the July-August 2014 eruption (2017)
    American Geophysical Union
    Details
    Publication Date: 2021-04-07
    Description: Integrating geodetic, seismic, and petrological data for a recent eruptive episode at Mount Etna has enabled us to define the history of magma storage and transfer within the multilevel structure of the volcano, providing spatial and temporal constraints for magma movements before the eruption. Geodetic data related to the July–August 2014 activity provide evidence of a magma reservoir at ~4 km below sea level. This reservoir pressurized from late March 2014 and fed magmas that were then erupted from vents on the lower eastern flank of North-East Crater (NEC) and at New South-East Crater (NSEC) summit crater during the July eruptive activity. Magma drainage caused its depressurization since mid-July. Textural and microanalytical data obtained from plagioclase crystals indicate similar disequilibrium textures and compositions at the cores in lavas erupted at the base of NEC and NSEC, suggesting comparable deep histories of evolution and ascent. Conversely, the compositional differences observed at the crystal rims have been associated to distinct degassing styles during storage in a shallow magma reservoir. Seismic data have constrained depth for a shallow part of the plumbing system at 1–2 km above sea level. Timescales of magma storage and transfer have also been calculated through diffusion modeling of zoning in olivine crystals of the two systems. Our data reveal a common deep history of magmas from the two systems, which is consistent with a recharging phase by more mafic magma between late March and early June 2014. Later, the magma continued its crystallization under distinct chemical and physical conditions at shallower levels.
    Description: The petrological part of this study was supported by the FIR 2014 research grant to Marco Viccaro from the University of Catania (Italy), grant number 2F119B, title of the project “Dynamics of evolution, ascent and emplacement of basic magmas: case-studies from eruptive manifestations of Eastern Sicily”.
    Description: Published
    Description: 5659–5678
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Petrology ; eruption ; GPS ; volcano seismology ; Etna ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 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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  • 73
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    Excess volatiles supplied by mingling of mafic magma at an andesite arc volcano (2010)
    AGU
    Details
    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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  • 74
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    The 2006 eruption of Mt. Etna (Italy): new multidisciplinary approach implemented by the UFSO staff of INGV Catania Section (2008)
    Details
    Publication Date: 2012-02-03
    Description: The 2006 eruption of Mt. Etna (Italy): new multidisciplinary approach implemented by the UFSO staff of INGV Catania Section S. Mangiagli, M. Neri, E. Pecora, D. Reitano, A. Amantia, E. Biale, M. D’Agostino, M. La Via and O. Torrisi Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, P. Roma, 2 - 95125, Catania Italy (mangiagli@ct.ingv.it, reitano@ct.ingv.it) During the latest (2006) eruptive activity of Mount Etna (Sicily - Italy) multidisciplinary instrumental networks and observations produced useful and significant data in order to understand the eruptive dynamics of this volcano. In this context, the staff of the INGV Catania Section Department called Unità Funzionale Sala Operativa (UFSO) actively participates in national and European research projects dealing with the development and use of new systems with high technological content useful, in particular, during eruptions or seismic crises. Another aspect of this work is represented by the development of software for the supervisory and automatic control of the working systems. For example during the last few weeks of 2006, ash-rich columns several km in height, and consequent fallout characterized the eruption of Mt Etna and severely hampered the functioning of the nearby International Airport of Catania. Therefore, for a better evaluation of real time systems a new dedicated web site has been realized, improving the availability of fundamental data for the Italian Department of Civil Defence (DPC). The DPC staff, using also INGV scientific data, releases daily bulletins to Italian government authorities. Multidisciplinary data are collected and well represented in risk maps. Moreover, various algorithms have been implemented and used to make simulations of eruptive clouds from Mt. Etna. All realized maps also use wind forecasts at different altitude and different scenarios are available in a new software able to plot different parameters like, for example, temperature and wind speed/direction in different isobaric levels, precipitation rate and total cloud cover.
    Description: INGV, Sezione Catania
    Description: Published
    Description: Vienna, Austria
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 5.5. Attività di Sala Operativa
    Description: open
    Keywords: Mmultidisciplinary approach ; Etna 2006 ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.06. Methods::05.06.99. General or miscellaneous
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  • 75
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    The recent eruptive activity of Mount Etna (Italy) monitored by a network of visible and thermal video cameras (2008)
    Details
    Publication Date: 2012-02-03
    Description: The recent eruptive activity of Mount Etna (Italy) monitored by a network of visible and thermal video cameras E. Biale, S. Mangiagli, M. Neri, E. Pecora, D. Reitano and B. Behncke Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, P. Roma, 2 - 95125, Catania Italy (pecora@ct.ingv.it, neri@ct.ingv.it) The recent eruptive activity of Mount Etna in Sicily (Italy) has been well documented by multidisciplinary instrumental observations, and significantly improved the understanding of the eruptive dynamics of this volcano. The monitoring networks are currently developed and managed by the Catania Section of the Istituto Nazionale di Geofisica e Vulcanologia (INGV). Video footage from the network of the monitoring video cameras is analyzed to discriminate between different eruptive typologies and to derive physical and dynamic properties of the eruptions. The cameras are located in four different places around the volcano (Schiena dell’Asino, Milo, Nicolosi and Catania), at respective distances of 5, 11, 15 and 27 km from the summit craters. Four video cameras record in the visible band and one in the Long-wave infrared (LWIR) over 24 hours/day. The images acquired by the Schiena dell’Asino camera are sent to a receiver in Catania, through a 10 GHz microwawe transmitter, whereas the signals from the other cameras are sent to Catania via 2 GHz video transmitters and/or cable. All images are digitized on computer, and archived on video tape and in AVI format with each clip representing 15 minutes compressed using 1 frame per two seconds, which are posted on the intranet server of the institute. A GPS Time-Code ads date and time to each frame before being digitized to 640 x 480 pixels. Meaningful frames are selected for analysis from footage of significant eruptive events, through dedicated software. The cumulative error regarding the measured parameters is estimated at up to 20%. In 2006, a new FLIR Thermavision A40M infrared camera was installed at Nicolosi. The camera detector is a 320 by 240 pixel uncooled microbolometer with a spectral range from 7.5 to 13 micrometer. Vertical and horizontal viewing is 18° and 24 , respectively, with a spatial resolution of 1.3 mrad. Thermal sensitivity is 0.08°C at 30°C. Thermal images are converted on board the camera into a single value for the peak temperature found in a region of interest centred on the active craters. This value is transmitted with a frequency of 1 Hz to the acquisition centre in Nicolosi. If a peak temperature value is less than 2°C than the preceding value then the relative change is added to the cumulative temperature value. Consequently, when the curve is near vertical the images registered by the thermal camera suggest increases in explosive/ effusive activity. On the contrary, if the curve is near horizontal the radiance of the eruptive theatre is constant or in diminution. Thermal images and thermal data are processed by dedicated software developed by LabVIEW 8.0 in detecting ash-rich eruptive columns, explosive and effusive activity. All these data are available at the INGV Control Centre and are used to alert on-duty staff in the early-warning procedures. This network of cameras furnished fundamental data to the Italian Civil Defence during the 2006 eruption, when ash-rich columns several km in height severely threatened the functioning of the nearby International Airport of Catania.
    Description: INGV, Sezione Catania
    Description: Published
    Description: Vienna, Austria
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: open
    Keywords: Nnetwork of visible and thermal video cameras ; Mount Etna ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.06. Methods::05.06.99. General or miscellaneous
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  • 76
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    High resolution velocity structure beneath Mount Vesuvius from seismic array data (2011)
    American Geophysical Union
    Details
    Publication Date: 2012-02-03
    Description: A high resolution P-wave image of Mt. Vesuvius edifice has been derived from simultaneous inversion of travel times and hypocentral parameters of local earthquakes, land based shots and small aperture array data. The results give detailsdownto300 – 500m.Therelocatedlocalseismicity appears to extend down to 5 km below the central crater, distributed in a major cluster, centered at 3 km below the central crater and in a minor group, with diffuse hypocenters inside the volcanic edifice. The two clusters are separated by an anomalously high Vp region at around 1 km depth. A zone with high Vp/Vs in the upper layers is interpreted as produced by the presence of intense fluid circulation. The highest energy quakes (up to M = 3.6) are located in the deeper cluster, in a high P-wave velocity zone. Our results favor an interpretation in terms of absence of shallow magma reservoirs.
    Description: Published
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: Velocity Tomography ; Mt. Vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 77
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    Tremor-based real time monitoring and early warning on Etna Volcano (Italy): technical aspects and methods (2013)
    INGV
    Details
    Publication Date: 2013-04-18
    Description: Twenty-five lava fountains occurred on Mt. Etna from January 2011 to April 2012. In summer 2012 volcanic activity resumed in a milder form within the Bocca Nuova crater, before it came to an essential halt in August 2012. All these unrests offer rich material for testing automatic procedures of data processing and alert systems, running 24/7, in the context of volcano surveillance. We focus on the seismic background radiation – volcanic tremor – which plays a key role in the monitoring of Mt. Etna. Since 2006 a multistation alert system has been established in the INGV operative centre of Catania exploiting STA/LTA ratios. Besides, also the spectral characteristics of the signal, which change correspondingly to the type of volcanic activity, can be exploited for warning purposes. Here we apply Self Organizing Maps and Fuzzy Clustering which offer an efficient way to visualize signal characteristics and its development with time. All these techniques allow to identify early stages of eruptive events, and automatically flag a critical status before this becomes evident in conventional monitoring techniques. Changes of tremor characteristics are related to the position of the source of the signal. The location of the sources exploits the distribution of the amplitudes across the seismic network. The locations were extremely useful for warning, throughout both the flank eruption in 2008 as well as the 2011 lava fountains, during which a clear migration of tremor sources towards the eruptive centres could be noticed in advance. The location of the sources completes the picture of an imminent volcanic unrest, and corroborates early warnings flagged by the changes of signal characteristics. Real time data processing requires computational efficiency, robustness of the methods and stability of data acquisition. The amplitude based multi-station approach is not sensitive to the failure of single stations and therefore offers a good stability. The single station approach, exploiting unsupervised classification techniques, limits logistic efforts, as only one or few key stations are necessary. Both strategies have proven to be insensitive to disturbances (undesired transients like earthquakes, noise, short gaps in the continuous data flow). False alarms were not encountered so far. Stable data acquisition and processing come with a properly designed data storage solution. The reliability of data storage and its access is a critical issue. A cluster architecture has been realized for failover protection, including a Storage Area Network system, which allow easy data access following predefined user policies. We present concepts of the software architectures deployed at INGV Osservatorio Etneo in order to implement this tremor-based multi approach system. We envisage the integration of seismic data and those originating from other scientific fields (e. g., volcano imagery, geochemistry, deformation, gravity, magneto-telluric). This will facilitate cross-checking of evidences encountered from the single data streams, in particular allow their immediate verification with respect to ground truth.
    Description: Published
    Description: Nicolosi (Catania, Italy)
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 5.6. TTC - Attività di Sala Operativa
    Description: open
    Keywords: Etna, Volcanic tremor ; Volcano monitoring, Pattern recognition ; Self Organizing Map, Fuzzy clustering ; Data acquisition ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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    Continuous soil CO2 and discrete plume SO2 measurements at Mt. Etna (Italy) during 1997-2000: a contribution to volcano monitoring (2005)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: Continuous monitoring of soil CO2 dynamic concentration (which is proportional to the CO2 flux through the soil) was carried out at a peripheral site of Mt. Etna during the period November 1997 - September 2000 using an automated station. The acquired data were compared with SO2 flux from the summit craters measured two to three times a week during the same period. The high frequency of data acquisition with both methods allowed us to analyze in detail the time variations of both parameters. Anomalous high values of soil CO2 dynamic concentration always preceded periods of increased flux of plume SO2, and these in turn were followed by periods of summit eruptions. The variations were modeled in terms of gas efflux increase due to magma ascent to shallow depth and its consequent depressurization and degassing. This model is supported by data from other geophysical and volcanological parameters. The rates of increase both of soil CO2 dynamic concentration and of plume SO2 flux are interpreted to be positively correlated both to the velocity of magma ascent within the volcano and to lava effusion rate once magma is erupted at the surface. Low rates of the increase were recorded before the nine-month-long 1999 subterminal eruption. Higher rates of increase were observed before the violent summit eruption of September-November 1999, and the highest rates were observed during shorter and very frequent spike-like anomalies that preceded the sequence of short-lived but very violent summit eruptions that started in late January 2000 and continued until late June of the same year. Furthermore, the time interval between the peaks of CO2 and SO2 in a single sequence of gas anomalies is likely to be controlled by magma ascent velocity.
    Description: Consiglio Nazionale delle Ricerche of Italy (C.N.R.)Gruppo Nazionale per la Vulcanologia.
    Description: Published
    Description: 80-89
    Description: partially_open
    Keywords: Mt. Etna ; Soil CO2 emissions ; Plume SO2 flux ; COSPEC ; Continuous geochemical monitoring ; Eruptive activity ; Degassing model ; 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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    Analysis of the seismo-volcanic and hydrothermal activity recorded on the Marsili submarine volcano (2011)
    Details
    Publication Date: 2012-02-03
    Description: Marsili is a back-arc volcano with a dominant tholeitic petrochemical affinity. This seamount, having an elevation of about 3000 m above the sea floor, an approximate length of 60 km in a NNE-SSW direction and a mean width of 25 km, is the biggest European volcano. The opening of the Marsili basin was related to a sharp acceleration of the roll-back of the Ionian lithosphere subducting below the Southern Tyrrhenian Basin. On the basis of all the geophysical, geological and petrological information knower, Marsili volcano can be considered as being the key needed to understand the dynamics of spreading and back-arc lithosphere formation in this Tyrrhenian sector. However, despite its importance in the Mediterranean geodynamical contest the seismo-volcanic and hydrothermal activity of this seamount remained little known. For this reason in 2006, in the framework of PRO.ME.TH.E.US project (Program of Mediterranean Exploration for Thermal Energy Use), founded by PRAMA s.r.l (Italy) (now Eurobuilding SpA), a multi-disciplinary research was conducted on the Marsili volcano area. In the framework of this project the INGV’s staff placed a broadband OBS/H (Ocean Bottom Seismometer with Hydrophone) on Marsili’s flat top (39° 16,383’ lat. Nord, 14° 23,588’ long. Est.) at a depth of 790 m. For this experiment the OBS/H operated from July 12th to 21st 2006. In only 9 days the submarine seismic station recorded more than 1000 seismo-volcanic and hydrothermal signals. By comparing the signals recorded with typical volcanic seismic activity, we group the recorded signals into: Volcano-Tectonic type B (817 VTB) events, occurrences of High Frequency Tremor (159 HFT) and quasi-monochromatic Short Duration Events (32 SDE). The small-magnitude VT-B swarms, having a frequency band of 2 - 6 Hz and a mean length of about 30 seconds, were almost all recorded during the first 7 days. During the last 2 days, the OBS/H mainly recorded HFT events with frequencies of over 40 Hz and few minutes length. On February 14th 2010, about three years and half after the first monitoring campaign another OBS/H was deployed in the same point for a long monitoring campaign (9 mouths). For this experiment the OBS/H was equipped with a Guralp CMG40T-OBS 3C seismometer, with flat transfer function in the band 60 s - 100 Hz, housed in a glass sphere with an autoleveling system that allows the sensor leveling in a range of ± 70° from the vertical. To monitor high frequency seismic and pressure signals the OBS/H was also equipped with a HTI-04- PCA/ULF Hydrophone, with a flat transfer function in the band 100s - 8 kHz. Both the signals were recorded by a 4 channels 21 bits SEND Geolon-MLS datalogger, at a sampling frequency of 200 Hz. During the nine months of the monitoring experiment the OBS/H recorded some thousand of little magnitude events very similar to that of the first experiment. The signals recorded in both the experiments were analyzed using polarization, spectral and clustering techniques. Both methods and results will be presented during the workshop.
    Description: Published
    Description: Salina Islands, Italy
    Description: 2.5. Laboratorio per lo sviluppo di sistemi di rilevamento sottomarini
    Description: open
    Keywords: Seismo-volcanic signals ; Marsili Seamount ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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    Geochemical monitoring of groundwaters (1998-2001) at Vesuvius volcano (Italy) (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This work presents the results of hydrogeochemical studies carried out at Vesuvius during the period May 1998 - December 2001, mostly focusing on compositional time variations observed during this time. Based on their chemistry, groundwater samples are distinguished into two groups, 1 and 2, representative of water circulation in the southern and northern sectors of the volcano, respectively. Waters from group 1 are typically more acidic, warmer,and more saline than those of group 2. They also have higher CO2 and CH4 contents, attributed to enhanced input of deep-rising volatiles and prolonged water-rock interactions. Time-series highlight the fairly constant chemical composition of the entire aquifer. Groundwater temperature, pH, bicarbonate content and dissolved CO2 display quite stable values in the study period, particularly in deep wells (piezometric level more than 100 m deep). Shallower water bodies present more evident temporal variations, related to seasonal and anthropogenic effects. This paper also describes some important variations in water chemistry which had occurred by the time of the seismic event in early October 1999, particularly in the Olivella spring located on the northern flank of the volcano. At this site, a great decrease in water pH and redox potential, and increased dissolved CO2 contents and 3He/4He ratios were observed. These changes in chemical and isotope composition support the hypothesis of an input of magma-derived helium and carbon dioxide into the aquifer feeding the Olivella spring by the time of the earthquake.
    Description: Published
    Description: 81-104
    Description: partially_open
    Keywords: Vesuvius ; volcanic surveillance ; groundwater ; hydro-geochemistry ; oxygen-18 ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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    Type: article
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    Magmatic gas leakage at Mount Etna (Sicily, Italy): relationships with the volcano-tectonic structures, the hydrological pattern and the eruptive activity (2005)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: In this paper we provide a review of chemical and isotopic data gathered over the last three decades on Etna volcano's fluid emissions and we present a synthetic framework of their spatial and temporal relationships with the volcano-tectonic structures, groundwater circulation and eruptive activity. We show that the chemistry, intensity and spatial distribution of gas exhalations are strongly controlled by the main volcano-tectonic fault systems. The emission of mantle-derived magmatic volatiles, supplied by deep to shallow degassing of alkali-hawaiitic basalts, persistently occurs through the central conduits, producing a huge volcanic plume. The magmatic derivation of the hot gases is verified by their He, C and S isotopic ratios. Colder but widespread emanations of magma-derived CO2 and He also occur through the flanks of the volcano and through aquifers, mainly concentrated within two sectors of the south-southwest (Paternò-Belpasso) and eastern (Zafferana) flanks. In these two peripheral areas, characterized by intense local seismicity and gravity highs, magma-derived CO2 and helium are variably diluted by shallower crustal-derived fluids (organically-derived carbon, radiogenic helium). Thermal and geochemical anomalies recorded in groundwaters and soil gases within these two areas prior to the 1991-1993 eruption are consistent with an input of hot fluids released by ascending magma. Magmatic fluids interacted with the shallow aquifers, modifying their physico-chemical conditions, and led to strong variations of the soil CO2 flux. In addition to routine survey of the crater plume emissions, geochemical monitoring of remote soil gases and groundwaters may thus contribute to forecasting Etna's eruptions.
    Description: Published
    Description: 129-145
    Description: partially_open
    Keywords: Mt. Etna ; Geochemical surveillance ; Groundwaters ; Volcanic gases ; 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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    A Measurement Tool for Investigating Cooling Lava Properties (2005)
    IEEE
    Details
    Publication Date: 2017-04-04
    Description: This paper presents the development and uncertainty characterization of a system for the direct measurement of heat transfer in cooling lava. The system continuously measures the parameters involved in the cooling process and, particularly, in the formation of the crust. The aim is to allow the future development of a physical model of the cooling process itself. In order to realize a system that will be effective in such a hostile environment, the principles on which the instruments for radiation thermometry are based have been thoroughly investigated. A virtual instrument has been developed, interfacing the measuring system and the user, processing the incoming data, and producing an estimate of the uncertainty of the measurement chain. The various sources of uncertainty have been taken into account to produce an accurate estimate of the uncertainty associated with the measured data. The results of experimental tests are presented.
    Description: Published
    Description: 507-513
    Description: open
    Keywords: Cooling lava measurement ; field point ; radiation thermometry ; whole system uncertainty estimate ; 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::04.08.07. Instruments and techniques
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    Type: article
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    S, Cl and F degassing as an indicator of volcanic dynamics: The 2001 eruption of Mount Etna (2005)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: The recent eruption of Mount Etna (July 2001) offered the opportunity to analyze magma-derived volatiles emitted during preand syn-eruptive phases, and to verify whether their composition is affected by changes in volcanic dynamics. This paper presents the results of analyses of F, Cl and S in the volcanic plume collected by filter-packs, and interprets variations in the composition based on contrasting solubility in magmas. A Rayleigh-type degassing mechanism was used to fit the acquired data and to estimate Henryâ s solubility constant ratios in Etnean basalt. This model provided insights into the dynamics of the volcano. Abundances of sulfur and halogens in eruptive plumes may help predict the temporal evolution of an ongoing effusive eruption.
    Description: -Gruppo Nazionale per la Vulcanologia.
    Description: Published
    Description: 1559
    Description: partially_open
    Keywords: magmatic degassing ; acidic gases ; plume chemistry ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 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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    Geophysical investigations at Stromboli volcano, Italy: implications for ground water flow and paroxysmal activity (2005)
    Blackwell
    Details
    Publication Date: 2017-04-04
    Description: Stromboli volcano (Italy) is characterized by a permanent mild explosive activity disrupted by major and paroxysmal eruptions. These strong eruptions could be triggered by phreatomagmatic processes. With the aim of obtaining a better understanding of ground water flow in the vicinity of the active vents, we carried out a set of geophysical measurements along two profiles crossing the Fossa area (through the Pizzo, the Large and the Small Fossa craters). These measurements include electrical resistivity, induced polarization, self-potential, temperature and CO2 ground concentration. These methods are used in order to delineate the crater boundaries, which act as preferential fluid flow pathways for the upflow of hydrothermal fluids. The absence of fumarolic activity in the Fossa area and the ground temperature close to 100 °C at a depth of 30 cm indicate that the hydrothermal fluids condense close to the ground surface. Part of this condensed water forms a shallow drainage network (〈20 m) in which groundwater flows downslope toward a perched aquifer. The piezometric surface of this aquifer is located ∼20 m below the topographic low of the Small Fossa crater and is close (〈100 m) to the active vents. Electrical resistivity tomography, temperature and CO2 measurements show that this shallow aquifer separates the underlying hydrothermal body from the ground surface. Further studies are needed to ascertain the size of this aquifer and to check its possible implications for the major and paroxysmal events observed at the Stromboli volcano.
    Description: Published
    Description: 426–440
    Description: partially_open
    Keywords: fluid flow ; CO2 soil concentration ; Self-potential ; Stromboli ; volcanic activity ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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    The first period of the 2002 Etna eruption (27 October-5 November): preliminary results (2005)
    INGV
    Details
    Publication Date: 2017-04-04
    Description: We report on the first period of the 2002 Etna eruption started on 27th October and ended on 5th November, occurring 15 months after the end of the 2001 eruption. Volcanological and geochemical data are presented in order to characterize the complex intrusion mechanism that contemporaneously involved the NE and S flanks of the volcano. Preliminary data outline that two distinct magma intrusions fed the eruptive fissures. Strong fire fountain activity mainly from the S fissure, produced copious ash fall in eastern Sicily, causing prolonged closure of Catania and Reggio Calabria airports. Lava emitted from the NE fissure formed a 6.2 km long lava flow field that destroyed the tourist facilities of Piano Provenzana area and part of Linguaglossa pine forest.
    Description: Published
    Description: 1-10
    Description: reserved
    Keywords: Volcanic eruption ; 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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    3-D Modelling of Campi Flegrei Ground Deformations: Role of Caldera Boundary Discontinuities (2006)
    Birkhauser Verlag
    Details
    Publication Date: 2017-04-04
    Description: Campi Flegrei is a caldera complex located west of Naples, Italy. The last eruption occurred in 1538, although the volcano has produced unrest episodes since then, involving rapid and large ground movements (up to 2 m vertical in two years), accompanied by intense seismic activity. Surface ground displacements detected by various techniques (mainly InSAR and levelling) for the 1970 to 1996 period can be modelled by a shallow point source in an elastic half-space, however the source depth is not compatible with seismic and drill hole observations, which suggest a magma chamber just below 4 km depth. This apparent paradox has been explained by the presence of boundary fractures marking the caldera collapse. We present here the first full 3-D modelling for the unrest of 1982–1985 including the effect of caldera bordering fractures and the topography. To model the presence of topography and of the complex caldera rim discontinuities, we used a mixed boundary elements method. The a priori caldera geometry is determined initially from gravimetric modelling results and refined by inversion. The presence of the caldera discontinuities allows a fit to the 1982–1985 levelling data as good as, or better than, in the continuous half-space case, with quite a different source depth which fits the actual magma chamber position as seen from seismic waves. These results show the importance of volcanic structures, and mainly of caldera collapses, in ground deformation episodes.
    Description: Published
    Description: 1329-1344
    Description: partially_open
    Keywords: Campi Flegrei ; deformations ; caldera ; 3-D ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 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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    Bayesian inversion of 1994-1998 vertical displacements at Mt Etna: evidence for magma intrusion (2006)
    Blackwell publishing
    Details
    Publication Date: 2017-04-04
    Description: We have developed a Bayesian method for the inversion of static ground deformations at volcanic areas.
    Description: Published
    Description: 935-946
    Description: partially_open
    Keywords: Bayesian inversion ; deformation ; Geodesy ; magma ; Mt Etna ; 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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    Relationships between diffuse CO2 emissions and volcanic activity on the island of Vulcano (Aeolian Islands, Italy) during the period 1984–1994 (2006)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: Measurements of CO2 flux from the ground were periodically carried out on the island of Vulcano (Aeolian Islands, Italy) between 1984 and 1994. Three high-flux areas were identified at the foot of the volcanic cone (La Fossa), either inside or very close to the main village. Effect of the choice of the sampling grid was evaluated. A different sampling grid resulted in similar distribution patterns, but with different CO2 fluxes. Therefore, the absolute estimate of the total flux from the investigated area includes a large degree of uncertainty, but repeated measurements with permanent sampling sites are accurate and can detect small changes. No correlation of the flux with atmospheric parameters was found at sites with high fluxes. Some periods characterized by high CO2 fluxes were observed, and a close correlation was found between the gas emissions from the ground and other geochemical and geophysical parameters such as temperature, chemical composition, steam, and SO2 flux from fumaroles, seismic energy release, and ground deformations. The results show that major temporal variations of diffuse CO2 flux are related to variations in volcanic activity.
    Description: Gruppo Nazionale per la Vulcanologia CNR Italy.
    Description: Published
    Description: 219–228
    Description: partially_open
    Keywords: CO2 ; Flux measurements ; Gas emissions ; Soil gas ; Volcanic activity ; Vulcano ; 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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    Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy (2006)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Sulphur speciation in volcanic gases acts as a major redox buffer, and H2S/SO2 ratios represent a valuable indicator of magmatic conditions and interactions between magmatic and hydrothermal fluids. However, measurement of H2S/SO2 even by direct sampling techniques, is not straightforward. We report here on application of a small ultraviolet spectrometer for real-time field measurement of H2S and SO2 concentrations, using open-path and extractive configurations. The device was tested at fumaroles on Solfatara and Vulcano, Italy, in November 2002. H2S concentrations of up to 220ppmm(400 ppmv) were measured directly above the Bocca Grande fumarole at Solfatara, and H2S/SO2 molar ratios of 2 and 2.4, respectively, were determined for the ‘F11’ and ‘F0’ fumaroles at Vulcano. In comparison with other optical techniques capable of multiple volcanic gas measurements, such as laser and FTIR spectroscopy, this approach is considerably simpler and cheaper, with the potential for autonomous, sustained hightime resolution operation.
    Description: Published
    Description: 1652
    Description: partially_open
    Keywords: Remote monitoring ; Plume chemistry ; sulphur species ; 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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    Seismic velocity structure and focal mechanism of the Umbria-Marche region (Central Italy) from local earthquake tomography (2006)
    Details
    Publication Date: 2017-04-04
    Description: Following the 26 September 1997 Colforito earthquakes, seismicity occurred for several months along a normal fault system composed by several adjacent NW trending segments distributed from Gualdo Tadino, in the north, to Sellano in the south. Earthquakes were recorded by several temporary seismic networks. We joined data collected from about 100 permanent and temporary seismic stations for a total complete dataset of several thousands of afstershocks. We present high resolution 3-D images of the Umbria-Marche region (central Italy) as derived from the inversion of P and S wave arrival times from $\sim$2000 crustal earthquakes belonging to the seismic crisis. Moreover, from the 3-D location of earthquakes, $\sim$600 focal mechanisms have been calculated by using the first polarities method.
    Description: Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
    Description: Unpublished
    Description: Nice, France
    Description: open
    Keywords: seismic ; umbria-marche ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Rapporto settimanale sull’attività eruttiva dell’Etna 6-13 Marzo 2006 (2006)
    Details
    Publication Date: 2017-04-04
    Description: Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania
    Description: Published
    Description: open
    Keywords: Mt. Etna ; volcanic surveillance ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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    DIFFERENT APPROACHES IN LOCAL EARTHQUAKE TOMOGRAPHY: AN APPLICATION ON THE ALBAN HILLS VOLCANO (CENTRAL ITALY) (2007)
    Details
    Publication Date: 2017-04-04
    Description: We compare the results of two different approaches in Local Earthquake Tomography (LET) as applied to the Alban Hills volcano. The first approach is called the graded inversion approach in which we progressively focused towards the center of the volcano while decreasing the model grid spacing in subsequent inversions, optimizing gradually the velocity model. The second approach is called the normal approach in which the seismic arrival times were directly inverted using a 1D velocity model optimally representing the background structure. The target region, i.e. Alban Hills volcano (or Vulcano Laziale) is a Quaternary age volcano laying about 20 km southeast of Rome, Italy. A micro seismic network temporarily installed on and around the volcano during a quake swarm gathered the arrival time data that we used. In the normal approach, we used three different grid spacings (i.e. 2, 1.5, and 1 km) that provided detailed images of the volcano. The resolution analysis carefully performed on the model parameters allowed the determination of a more reliable final model that represented the best results for the velocity structure beneath the volcano. The inversion results attained with the graded approach were not satisfactory, as some small-scale heterogeneities were not properly detected as done by the inversion with the normal approach. The normal approach in fact revealed a horn shaped structure with a high velocity located beneath the volcano and a low velocity anomaly dominated the depths around 1-4 km in western side of the volcano. In general, the graded approach relative to the normal approach failed to detect the fine details of the volcano.
    Description: Submitted
    Description: open
    Keywords: Local Earthquake Tomography, Alban Hills Volcano, 3D Velocity Structure ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: manuscript
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    Seismic anisotropy reveals focused mantle flow around the Calabrian slab (Southern Italy) (2007)
    AGU
    Details
    Publication Date: 2017-04-04
    Description: SKS splitting at the Calabrian subduction zone, with delay times (δt) up to 3s, reveals the presence of a strong anisotropic fabric. Fast directions (ϕ) are oriented NNE-SSW in the Calabrian Arc (C.A.) and rotate NNW-SSE to the north following the arcuate shape of the subducting plate. We interpret the trench-parallel ϕ as local-scale mantle flow driven by the retrograde motion of the slab; the absence of trench perpendicular ϕ below the Southern Apennines (S.A.) excludes the presence of a seismically detectable return flow at its NE edge. This may be due to the relative youth and limited width of the S.A. slab tear. A possible return flow is identified farther north at the boundary of the S.A. and Central Apennines. Different and weaker anisotropy is present below the Apulian Platform (A.P.). This implies that the influence of the slab rollback in the sub-slab mantle is limited to less then 100 km from the slab.
    Description: Published
    Description: L05302
    Description: JCR Journal
    Description: open
    Keywords: shear-wave splitting, calabrian subduction zone ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 94
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    Rock properties of the upper-crust in Central Apennines (Italy) derived from high-resolution 3-D tomography (2007)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: High-resolution 3-D P and S-wave velocity models of a central sector of the Apennines (Central Italy) are computed by inverting first arrival times from an aftershock sequence (September–December, 1997) following the Mw 5.7 and Mw 6.0 Umbria-Marche earthquakes that occurred on September 26, 1997. The high quality of the data set, especially for the S-wave, allows us to compute 3-D variations in Vp, Vp/Vs and Vp · Vs. The anomalies can be interpreted as lateral changes in rock type and fracturing, which control fluid diffusion and variation in pore pressure. This is in agreement with a poro-elastic view that can be inferred from the spatio-temporal evolution of the seismic sequence.
    Description: Published
    Description: 61-4
    Description: open
    Keywords: Physical properties of rocks ; Seismicity and seismotectonics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 95
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    Insights into the internal dynamics of Etna volcano through discrete and continuous microgravity observations (2007)
    Details
    Publication Date: 2017-04-04
    Description: Discrete and continuous microgravity observations have been routinely performed at Mt. Etna since 1986 and 1998, respectively. Besides furnishing a full view of how gravity measurements from Etna are accomplished and reduced, this paper is a collection of case studies aimed at demonstrating the potential of microgravity studies to investigate the plumbing system of an active volcano and detect forerunners to paroxysmal volcanic events. As for discrete measurements, case studies relative to the 1994-96 and 2001 periods are reported. During the first period, the observed gravity changes are interpreted within the framework of the strombolian activity which occurred from the summit craters. Gravity changes observed during the first 9 months of 2001 are directly related to the underground mass redistributions who preceded, accompanied and followed the July-August 2001 flank eruption of Etna. As for continuous measurements, a three-year (1998-2000) sequence and a 48-hour (26-28 October 2002) sequence, both from PDN station, are presented and discussed. The first one is maybe the longest continuous gravity sequence ever acquired at a station very close to the summit zone of an active volcano. It allows to discover the cyclic character of a source whose geometrical characteristics are retrieved through data from discrete measurements. The second sequence is also likely to represent an unique item: a gravity sequence encompassing the onset of an eruption and coming from a station only 1.5 km from the eruptive fissures. It allows some constraints to be set on the characteristics of the intrusive mechanism leading to the eruption.
    Description: Submitted
    Description: open
    Keywords: Mt Etna ; microgravity ; magma sources ; modeling ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: manuscript
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  • 96
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    Intrusive mechanism of the 2002 NE-rift eruption at Mt Etna (Italy) (2007)
    Details
    Publication Date: 2017-04-04
    Description: Microgravity and GPS data collected at Mt Etna during a 1-yr time interval encompassing the 2002 NE-rift eruption are analysed. The common GPS-gravity profile traverses the summit area of Mt Etna, between the summit craters (about 3000 m) and the northernmost tip of the eruptive fractures (2500 m). Displacements (up to 2 m in both the horizontal and vertical directions) and gravity variations (up to 350 μGal, after having removed the effect of elevation changes) observed during this period are among the largest ever recorded at Etna. Displacements and gravity changes have been modelled separately, assuming a magma influx from the summit feeder pipe to the NE-rift. Models obtained through surface deformation data partially overlap with those explaining the gravity data but in general are narrower and extend to a greater depth. The discrepancies found between gravity and deformation models are significant and can be regarded as due to the different structural features encountered by the intruding magma during its downslope propagation along the NE-rift. In particular, on the grounds of our result, we infer that both the eastward sliding of the east flank of the volcano and the curved shape of the NE-rift influenced the 2002 intrusive process.
    Description: Published
    Description: 339-347
    Description: reserved
    Keywords: deformation ; density ; dislocation ; gravity anomalies ; magma flow ; rifts ; volcanic ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 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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  • 97
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    An advanced video-based system for monitoring active volcanoes (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Video surveillance systems are consolidated techniques for monitoring eruptive phenomena in volcanic areas. Along with these systems, which use standard video cameras, people working in this field sometimes make use of infrared cameras providing useful information about the thermal evolution of eruptions. Real-time analysis of the acquired frames is required, along with image storing, to analyze and classify the activity of volcanoes. Human effort and large storing capabilities are hence required to perform monitoring tasks. In this paper we present a new strategy aimed at improving the performance of video surveillance systems in terms of human-independent image processing and storing optimization. The proposed methodology is based on real-time thermo-graphic analysis of the area considered. The analysis is performed by processing images acquired with an IR camera and extracting information about meaningful volcanic events. Two software tools were developed. The first provides information about the activity being monitored and automatically adapts the image storing rate. The second tool automatically produces useful information about the eruptive activity encompassed by a selected frame sequence. The software developed includes a suitable user interface allowing for convenient management of the acquired images and easy access to information about the volcanic activity monitored.
    Description: Published
    Description: 85-91
    Description: reserved
    Keywords: Volcano monitoring ; Image processing ; Smart storing rate ; Eruption data ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 98
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    Time-resolved seismic tomography detects magma intrusions at Mt. Etna (2007)
    American Association for the Advancement of Science
    Details
    Publication Date: 2017-04-04
    Description: The continuous volcanic and seismic activity at Mount Etna makes this volcano an important laboratory for seismological and geophysical studies. We used repeated three-dimensional tomography to detect variations in elastic parameters during different volcanic cycles, before and during the October 2002–January 2003 flank eruption. Well-defined anomalous low P- to S-wave velocity ratio volumes were revealed. Absent during the pre-eruptive period, the anomalies trace the intrusion of volatile-rich (Q4 weight percent) basaltic magma, most of which rose up only a few months before the onset of eruption. The observed time changes of velocity anomalies suggest that four-dimensional tomography provides a basis for more efficient volcano monitoring and shortand midterm eruption forecasting of explosive activity.
    Description: Published
    Description: 821-823
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 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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  • 99
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    Imaging composite dike propagation (Etna, 2002 case) (2007)
    AGU
    Details
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 100
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    Rapporto sulle misure di CO2 e mercurio nei suoli e nell’atmosfera e sui dati in continuo di radon nel suolo presso la zona sommitale dell’Etna (17 Luglio 2006) (2007)
    Details
    Publication Date: 2017-04-04
    Description: A seguito dell’attività eruttiva iniziatasi sull’Etna giorno 14 Luglio, sono state effettuate varie misure di gas sia nei suoli che in atmosfera nell’intorno di Torre del Filosofo (Figura 1), dove già da tempo si monitorizza l’emissione di CO2 e radon nel terreno sia in maniera continua (radon) che discontinua (CO2). Inoltre, sono state anche effettuate misure di concentrazione di mercurio sia nei suoli che nell’aria, accoppiate alle misure di CO2. Infine, sono stati scaricati i dati di radon dalla sonda in continuo istallata nello stesso sito nel Luglio 2005 (Neri et al., 2006).
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Unpublished
    Description: open
    Keywords: NONE ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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