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  • 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
  • Elsevier  (40)
  • American Geophysical Union  (26)
  • 1
    Publication Date: 2020-06-03
    Description: The ongoing unrest at the Campi Flegrei caldera (CFc) in southern Italy is prompting exploration of its poorly studied offshore sector. We report on a multidisciplinary investigation of the Secca delle Fumose (SdF), a submarine relief known since antiquity as the largest degassing structure of the offshore sector of CFc. We combined high-resolution morphobathymetric and seismostratigraphic data with onshore geological information to propose that the present-day SdF morphology and structure developed during the initial stages of the last CFc eruption at Monte Nuovo in AD 1538. We suggest that the SdF relief stands on the eastern uplifted border of a N-S-trending graben-like structure formed during the shallow emplacement of the Monte Nuovo feeding dike. We also infer that the high-angle bordering faults that generated the SdF relief now preferentially allow the ascent of hot brines (with an equilibrium temperature of 1798C), thereby sustaining hydrothermal degassing on the seafloor. Systematic vertical seawater profiling shows that hydrothermal seafloor venting generates a sizeable CO2, pH, and temperature anomaly in the overlying seawater column. Data for the seawater vertical profile can be used to estimate the CO2 and energy (heat) outputs from the SdF area at 50 tons/d ( 0.53 kg/s) and 80 MW, respectively. In view of the cause-effect relationship with the Monte Nuovo eruption, and the substantial gas and energy outputs, we consider that the SdF hydrothermal system needs to be included in monitoring programs of the ongoing CFc unrest.
    Description: Published
    Description: 4153–4178
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: Hydrothermal fluid ; Campi Flegrei caldera ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 2
    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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  • 3
    Publication Date: 2021-05-12
    Description: An accelerating process of ground deformation that began 10 years ago is currently affecting the Campi Flegrei caldera. The deformation pattern is here explained with the overlapping of two processes: short time pulses that are caused by injection of magmatic fluids into the hydrothermal system; and a long time process of heating of the rock. The short pulses are highlighted by comparison of the residuals of ground deformation (fitted with an accelerating polynomial function) with the fumarolic CO2/CH4 and He/CH4 ratios (which are good geochemical indicators of the arrival of magmatic gases). The two independent datasets show the same sequence of five peaks, with a delay of ∼200 days of the geochemical signal with respect to the geodetic signal. The heating of the hydrothermal system, which parallels the long-period accelerating curve, is inferred by temperature–pressure gas geoindicators. Referring to a recent interpretation that relates variations in the fumarolic inert gas species to open system magma degassing, we infer that the heating is caused by enrichment in water of the magmatic fluids and by an increment in their flux. Heating of the rock caused by magmatic fluids can be a central factor in triggering unrest at calderas.
    Description: Published
    Description: 58-67
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Campi Flegrei Caldera ; hydrothermal system ; ground deformation ; magmatic fluids ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    Publication Date: 2017-04-04
    Description: There have been limited studies to date targeting gaseous elemental mercury (GEM) flux from soil emission in enriched volcanic substrates and its relation with CO2 release and tectonic structures. In order to evaluate and understand the processes of soil–air exchanges involved at Solfatara of Pozzuoli volcano, the most active zone of Campi Flegrei caldera (Italy), an intensive field measurement survey has been achieved in September 2013 by using high-time resolution techniques. Soil–air exchange fluxes of GEM and CO2 have been measured simultaneously at 116 points, widely distributed within the crater. Quantification of gas flux has been assessed by using field accumulation chamber method in conjunction with a Lumex®-RA 915 + portable mercury vapor analyzer and a LICOR for CO2 determination, respectively. The spatial distribution of GEM and CO2 emissions correlated quite closely with the hydrothermal and geological features of the studied area. The highest GEM fluxes (from 4.04 to 5.9 × 10− 5 g m− 2 d− 1) were encountered close to the southern part of the crater interested by an intense fumarolic activity and along the SE–SW tectonic fracture (1.26 × 10− 6–6.91 × 10− 5 g GEM m− 2 d− 1). Conversely, the lowest values have been detected all along the western rim of the crater, characterized by a weak gas flux and a lush vegetation on a very sealed clay soil, which likely inhibited mercury emission (range: 1.5 × 10− 7–7.18 × 10− 6 g GEM m− 2 d− 1). Results indicate that the GEM exchange between soil and air inside the Solfatara crater is about 2–3 orders of magnitude stronger than that in the background areas (10− 8–10− 7 g m− 2 d− 1). CO2 soil diffuse degassing exhibited an analogous spatial pattern to the GEM fluxes, with emission rates ranging from about 15 to ~ 20,000 g CO2 m− 2 d− 1, from the outermost western zones to the south-eastern sector of the crater. The observed significant correlation between GEM and CO2 suggested that in volcanic system GEM volatilizes from substrate in a similar manner to the release of CO2. The quantitative estimation of the total amount of CO2 and GEM released from the Solfatara crater gave values of about 304 ± 13 and 3.7 ± 0.2 × 10− 6 t d− 1, respectively. Finally, based on our dataset and previous work, we propose that an average GEM/CO2 molar ratio of ~ 2 × 10− 8 (n = 9) is best representative of hydrothermal degassing. Taking into account the uncertainty in global hydrothermal CO2 emissions from sub-aerial environments (~ 1012 Mol yr− 1), we infer a global volcanic GEM flux from hydrothermal environments of ~ about 8.5 t yr− 1. Although this value has to be considered as a lower limit for the global emission of GEM from these sources, we suggest that on a local scale hydrothermal activity can be regarded as a significant source of GEM than previously recognized to the atmospheric pool.
    Description: Published
    Description: 26-40
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: Flux Chamber Survey ; Mercury ; CO2 emissions ; Solfatara ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publication Date: 2017-04-04
    Description: High-speed imaging of explosive eruptions at Stromboli (Italy), Fuego (Guatemala), and Yasur (Vanuatu) volcanoes allowed visualization of pressure waves from seconds-long explosions. From the explosion jets, waves radiate with variable geometry, timing, and apparent direction and velocity. Both the explosion jets and their wave fields are replicated well by numerical simulations of supersonic jets impulsively released from a pressurized vessel. The scaled acoustic signal from one explosion at Stromboli displays a frequency pattern with an excellent match to those from the simulated jets. We conclude that both the observed waves and the audible sound from the explosions are jet noise, i.e., the typical acoustic field radiating from high-velocity jets. Volcanic jet noise was previously quantified only in the infrasonic emissions from large, sub-Plinian to Plinian eruptions. Our combined approach allows us to define the spatial and temporal evolution of audible jet noise from supersonic jets in small-scale volcanic eruptions.
    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 “NEMOH” ITN projects
    Description: Published
    Description: 3096–3102
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: jet noise ; volcano acoustics ; Stromboli ; Yasur ; Fuego ; strombolian eruption ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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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  • 6
    Publication Date: 2017-04-04
    Description: Starting off from a review of previous literature on kinematic models of the unstable eastern flank of Mt. Etna, we propose a new model. The model is based on our analysis of a large quantity of multidisciplinary data deriving from an extensive and diverse network of INGV monitoring devices deployed along the slopes of the volcano. Our analysis had a twofold objective: first, investigating the origin of the recently observed slow-slip events on the eastern flank of Mt. Etna; and second, defining a general kinematic model for the instability of this area of the volcano. To this end, we investigated the 2008–2013 period using data collected from different geochemical, geodetic, and seismic networks, integrated with the tectonic and geologic features of the volcano and including the volcanic activity during the observation period. The complex correlations between the large quantities of multidisciplinary data have given us the opportunity to infer, as outlined in this work, that the fluids of volcanic origin and their interrelationship with aquifers, tectonic and morphological features play a dominant role in the large scale instability of the eastern flank of Mt. Etna. Furthermore, we suggest that changes in the strain distribution due to volcanic inflation/deflation cycles are closely connected to changes in shallow depth fluid circulation. Finally, we propose a general framework for both the short and long term modeling of the large flank displacements observed.
    Description: Published
    Description: 635–658
    Description: 1IT. Reti di monitoraggio e Osservazioni
    Description: JCR Journal
    Description: restricted
    Keywords: Mt. Etna ; monitoring data ; GPS ; flank instability ; gas geochemistry ; volcanic tremor ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2017-04-04
    Description: From 2006 to spring 2013, Campi Flegrei (CF) caldera, Italy, was mostly uplifting at an increasing rate, particularly high from 2011. We show that the 2011–2013 accelerated uplift and 1980–2010 inflation and deflation phases can be explained by a two-source conceptual model similar to that proposed by Amoruso et al. (2014) (reference model). However, pressurization of the sole thin quasi-horizontal ∼4000 m deep source, responsible for large-scale 1980–2010 deformation, can explain the whole 2011–2013 deformation, while activity of the shallower Solfatara hydrothermal source, responsible for residual 1980–2010 deformation, appears constant. These results suggest a predominantly magmatic unrest in 2011–2013. Near-real-time comparison of observations and reference model predictions can provide additional information for short-term eruption forecasting at CF; a similar approach could be followed also in other volcanic environments.
    Description: Published
    Description: 3081–3088
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: The two sources of 1980–2010 CF deformation satisfy also the 2011–2013 unrest ; Pressurization of the sole ∼4000 m deep source satisfies the whole deformation ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
    Publication Date: 2017-04-04
    Description: The statistical analysis of volcanic activity at Mt Etna was conducted with the twofold aim of (1) constructing a probability map for vent opening of future flank eruptions and (2) forecasting the expected number of eruptive events at the summit craters. The spatiotemporal map of new vent opening at Etna volcano is based on the analysis of spatial locations and frequency of flank eruptions starting from 1610. Thanks to the completeness and accuracy of historical data over the last four centuries, we examined in detail the spatial and temporal distribution of flank eruptions showing that effusive events follow a nonhomogenous Poisson process with space-time varying intensities. After demonstrating the spatial nonhomogeneity and the temporal nonstationarity of flank eruptions at Etna, we calculated the recurrence rates (events expected per unit area per unit time) and produced different spatiotemporal probability maps of new vent opening in the next 1, 10 and 50 years. These probabilistic maps have an immediate use in evaluating the future timing and areas of Etna prone to volcanic hazards. Finally, the results of the analysis of the persistent summit activity during the last 110 years indicate that the hazard rate for eruptive events is not constant with time, differs for each summit crater of Mt Etna, highlighting a general increase in the eruptive frequency starting from the middle of last century and particularly from 1971, when the SE crater was formed.
    Description: This work was developed in the frame of the TecnoLab, the Laboratory for the Technological Advance in Volcano Geophysics organized by INGV-CT, DIEES-UNICT, and DMI-UNICT.
    Description: Published
    Description: 1925-1935
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 3V. Dinamiche e scenari eruttivi
    Description: 4V. Vulcani e ambiente
    Description: 3IT. Calcolo scientifico e sistemi informatici
    Description: JCR Journal
    Description: restricted
    Keywords: Etna ; probabilistic modeling ; eruption ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 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
    Publication Date: 2017-04-04
    Description: Flank instability at basaltic volcanoes is often related to repeated dike intrusions along rift zones and accompanied by surface fracturing and seismicity. These processes have been mostly studied during specific events, and the lack of longer-term observations hinders their better understanding. Here we analyze ~20 years of deformation of the Pernicana Fault System (PFS), the key structure controlling the instability of the eastern flank of Mt. Etna. We exploit East-West and vertical components of mean deformation velocity, as well as corresponding time series, computed from ERS/ENVISAT (1992–2010) and COSMO-SkyMed (2009–2011) satellite radar sensors via Synthetic Aperture Radar Interferometry techniques. We then integrate and compare this information with field, seismic, and leveling data, collected between 1980 and 2012. We observe transient displacements accompanied by seismicity, overprinted on a long-term background eastward motion (~2 cm/yr). In the last decades, these transient events were preceded by a constant amount of accumulated strain near the PFS. The time of strain accumulation varies between a few years and a few decades, also depending on magma emplacement within the nearby North East Rift, which may increase the strain along the PFS. These results suggest that the amount of deformation near the PFS may be used as a gauge to forecast the occurrence of instability transients on the eastern flank of Etna. In this context, the PFS may provide an ideal, small-scale structure to test the relations between strain accumulation, stress loading, and seismic energy release.
    Description: This work has been partially supported by the Italian Space Agency (ASI) within the SAR4Volcanoes project, agreement I/ 034/11/0.
    Description: Published
    Description: 4398-4409
    Description: 1T. Geodinamica e interno della Terra
    Description: 2T. Tettonica attiva
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: 5T. Sorveglianza sismica e operatività post-terremoto
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 3V. Dinamiche e scenari eruttivi
    Description: 4V. Vulcani e ambiente
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: JCR Journal
    Description: restricted
    Keywords: Volcano flank instability ; Pernicana fault ; Etna ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 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::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2017-04-04
    Description: Volcanic eruptions are often accompanied by spatiotemporal migration of ground deformation, a consequence of pressure changes within magma reservoirs and pathways. We modeled the propagation of pressure variations through the east rift zone (ERZ) of K" ılauea Volcano, Hawai‘i, caused by magma " o-Kupaianaha withdrawal during the early eruptive episodes (1983–1985) of the ongoing Pu‘u ‘ O‘" " eruption. Eruptive activity at the Pu‘u ‘ O‘" o vent was typically accompanied by abrupt deflation that lasted for several hours and was followed by a sudden onset of gradual inflation once the eruptive episode had ended. Similar patterns of deflation and inflation were recorded at K" ılauea’s summit, approximately 15 km to the northwest, albeit with time delays of hours. These delay times can be reproduced by modeling the spatiotemporal changes in magma pressure and flow rate within an elastic-walled dike that traverses K" ılauea’s ERZ. Key parameters that affect the behavior of the magma-dike system are the dike dimensions, the elasticity of the wall rock, the magma viscosity, and to a lesser degree the magnitude and duration of the pressure variations themselves. Combinations of these parameters define a transport efficiency and a pressure diffusivity, which vary somewhat from episode to episode, resulting in variations in delay times. The observed variations in transport efficiency are most easily explained by small, localized changes to the geometry of the magma pathway
    Description: Published
    Description: 2232–2246
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: magma flow ; dikes ; Kilauea ; elastic rock ; magma-rock coupling ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2021-05-17
    Description: During AprileMay 2010 volcanic ash clouds from the Icelandic Eyjafjallajökull volcano reached Europe causing an unprecedented disruption of the EUR/NAT region airspace. Civil aviation authorities banned all flight operations because of the threat posed by volcanic ash to modern turbine aircraft. New quantitative airborne ash mass concentration thresholds, still under discussion, were adopted for discerning regions contaminated by ash. This has implications for ash dispersal models routinely used to forecast the evolution of ash clouds. In this new context, quantitative model validation and assessment of the accuracies of current state-of-the-art models is of paramount importance. The passage of volcanic ash clouds over central Europe, a territory hosting a dense network of meteorological and air quality observatories, generated a quantity of observations unusual for volcanic clouds. From the ground, the cloud was observed by aerosol lidars, lidar ceilometers, sun photometers, other remote-sensing instruments and in-situ collectors. From the air, sondes and multiple aircraft measurements also took extremely valuable in-situ and remote-sensing measurements. These measurements constitute an excellent database for model validation. Here we validate the FALL3D ash dispersal model by comparing model results with ground and airplane-based measurements obtained during the initial 14e23 April 2010 Eyjafjallajökull explosive phase. We run the model at high spatial resolution using as input hourlyaveraged observed heights of the eruption column and the total grain size distribution reconstructed from field observations. Model results are then compared against remote ground-based and in-situ aircraft-based measurements, including lidar ceilometers from the German Meteorological Service, aerosol lidars and sun photometers from EARLINET and AERONET networks, and flight missions of the German DLR Falcon aircraft. We find good quantitative agreement, with an error similar to the spread in the observations (however depending on the method used to estimate mass eruption rate) for both airborne and ground mass concentration. Such verification results help us understand and constrain the accuracy and reliability of ash transport models and it is of enormous relevance for designing future operational mitigation strategies at Volcanic Ash Advisory Centers.
    Description: Published
    Description: 165-183
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: restricted
    Keywords: Volcanic ash dispersion ; Numerical model ; Model validation ; 2010 Eyjafjallajökull eruption ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2017-04-04
    Description: Spaceborne remote sensing techniques and numerical simulations have been combined in a web-GIS framework (LAV@HAZARD) to evaluate lava flow hazard in real time. By using the HOTSAT satellite thermal monitoring system to estimate time-varying TADR (time averaged discharge rate) and the MAGFLOW physicsbased model to simulate lava flow paths, the LAV@HAZARD platform allows timely definition of parameters and maps essential for hazard assessment, including the propagation time of lava flows and the maximum run-out distance. We used LAV@HAZARD during the 2008–2009 lava flow-forming eruption at Mt Etna (Sicily, Italy). We measured the temporal variation in thermal emission (up to four times per hour) during the entire duration of the eruption using SEVIRI and MODIS data. The time-series of radiative power allowed us to identify six diverse thermal phases each related to different dynamic volcanic processes and associated with different TADRs and lava flow emplacement conditions. Satellite-derived estimates of lava discharge rates were computed and integrated for the whole period of the eruption (almost 14 months), showing that a lava volume of between 32 and 61 million cubic meters was erupted of which about 2/3 was emplaced during the first 4 months. These time-varying discharge rates were then used to drive MAGFLOW simulations to chart the spread of lava as a function of time. TADRs were sufficiently low (b30 m3/s) that no lava flows were capable of flowing any great distance so that they did not pose a hazard to vulnerable (agricultural and urban) areas on the flanks of Etna.
    Description: Published
    Description: 197-207
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Etna volcano Infrared remote sensing Numerical simulation GIS Lava hazard assessment ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous
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  • 13
    Publication Date: 2017-04-04
    Description: Large magnitude explosive eruptions are the result of the rapid and large-scale transport of silicic magma stored in the Earth's crust, but the mechanics of erupting teratonnes of silicic magma remain poorly understood. Here, we demonstrate that the combined effect of local crustal extension and magma chamber overpressure can sustain linear dyke-fed explosive eruptions with mass fluxes in excess of 1010 kg/s from shallow-seated (4–6 km depth) chambers during moderate extensional stresses. Early eruption column collapse is facilitated with eruption duration of the order of few days with an intensity of at least one order of magnitude greater than the largest eruptions in the 20th century. The conditions explored in this study are one way in which high mass eruption rates can be achieved to feed large explosive eruptions. Our results corroborate geological and volcanological evidences from volcano-tectonic complexes such as the Sierra Madre Occidental (Mexico) and the Taupo Volcanic Zone (New Zealand).
    Description: Published
    Description: 161-166
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: restricted
    Keywords: conduit model ; large explosive eruption ; extensional stress ; linear fissure eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 14
    Publication Date: 2017-04-03
    Description: The study of geodynamics relies on an understanding of the strength of the lithosphere. However, our knowledge of kilometer‐scale rheology has generally been obtained from centimeter‐sized laboratory samples or from microstructural studies of naturally deformed rocks. In this study, we present a method that allows rheological examination at a larger scale. Utilizing forward numerical modeling, we simulated lithospheric deformation as a function of heat flow and rheological parameters and computed several testable predictions including horizontal velocities, stress directions, and the tectonic regime. To select the best solutions, we compared the model predictions with experimental data. We applied this method in Italy and found that the rheology shows significant variations at small distances. The strength ranged from 0.6 ± 0.2 TN/m within the Apennines belt to 21 ± 6 TN/m in the external Adriatic thrust. These strength values correspond to an aseismic mantle in the upper plate and to a strong mantle within the Adriatic lithosphere. With respect to the internal thrust, we found that strike‐slip or transpressive, but not compressive, earthquakes can occur along the deeper portion of the thrust. The differences in the lithospheric strength are greater than our estimated uncertainties and occur across the Adriatic subduction margin. Using the proposed method, the lithospheric strength can be also determined when information at depth is scarce but sufficient surface data are available. Citation: Carafa, M. M. C., and S. Barba (2011), Determining rheology from deformation data: The case of central Italy, Tectonics, 30, TC2003, doi:10.1029/2010TC002680.
    Description: Published
    Description: TC2003
    Description: JCR Journal
    Description: restricted
    Keywords: Rheology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 15
    Publication Date: 2017-04-04
    Description: This paper presents a magnetotelluric (MT) survey of the unstable eastern flank of Mt. Etna. We take thirty soundings along two profiles oriented in the N-S and NW-SE directions, and from these data recover two 2D resistivity models of the subsurface. Both models reveal three major layers in a resistive-conductive-resistive sequence, the deepest extending to 14 km bsl. The shallow layer corresponds to the volcanic cover, and the intermediate conductive layer corresponds to underlying sediments segmented by faults. These two electrical units are cut by E-W-striking faults. The third layer (basement) is interpreted as mainly pertinent to the Apennine-Maghrebian Chain associated with SW-NE-striking regional faults. The detailed shapes of the resistivity profiles clearly show that the NE Rift is shallow-rooted ( 0–1 km bsl), thus presumably fed by lateral dikes from the central volcano conduit. The NW-SE profile suggests by a series of listric faults reaching up to 3 km bsl, then becoming almost horizontal. Toward the SE, the resistive basement dramatically dips (from 3 km to 10 km bsl), in correspondence with the Timpe Fault System. Several high-conductivity zones close to the main faults suggest the presence of hydrothermal activity and fluid circulation that could enhance flank instability. Our results provide new findings about the geometry of the unstable Etna flank and its relation to faults and subsurface structures.
    Description: This paper presents a magnetotelluric (MT) survey of the unstable eastern flank of Mt. Etna. We take thirty soundings along two profiles oriented in the N-S and NW-SE directions, and from these data recover two 2D resistivity models of the subsurface. Both models reveal three major layers in a resistive-conductive-resistive sequence, the deepest extending to 14 km bsl. The shallow layer corresponds to the volcanic cover, and the intermediate conductive layer corresponds to underlying sediments segmented by faults. These two electrical units are cut by E-W-striking faults. The third layer (basement) is interpreted as mainly pertinent to the Apennine-Maghrebian Chain associated with SW-NE-striking regional faults. The detailed shapes of the resistivity profiles clearly show that the NE Rift is shallow-rooted ( 0–1 km bsl), thus presumably fed by lateral dikes from the central volcano conduit. The NW-SE profile suggests by a series of listric faults reaching up to 3 km bsl, then becoming almost horizontal. Toward the SE, the resistive basement dramatically dips (from 3 km to 10 km bsl), in correspondence with the Timpe Fault System. Several high-conductivity zones close to the main faults suggest the presence of hydrothermal activity and fluid circulation that could enhance flank instability. Our results provide new findings about the geometry of the unstable Etna flank and its relation to faults and subsurface structures.
    Description: Published
    Description: B03216
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: restricted
    Keywords: Etna ; magnetotelluric ; flank instability ; volcano ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 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::04.05. Geomagnetism::04.05.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
    Publication Date: 2017-04-04
    Description: Volcanic rift zones, characterized by repeated dike emplacements, are expected to delimit the upper portion of unstable flanks at basaltic edifices. We use nearly two decades of InSAR observations excluding wintertime acquisitions, to analyze the relationships between rift zones, dike emplacement and flank instability at Etna. The results highlight a general eastward shift of the volcano summit, including the northeast and south rifts. This steadystate eastward movement (1-2 cm/yr) is interrupted or even reversed during transient dike injections. Detailed analysis of the northeast rift shows that only during phases of dike injection, as in 2002, does the rift transiently becomes the upper border of the unstable flank. The flank's steady-state eastward movement is inferred to result from the interplay between magmatic activity, asymmetric topographic unbuttressing, and east-dipping detachment geometry at its base. This study documents the first evidence of steady-state volcano rift instability interrupted by transient dike injection at basaltic edifices.
    Description: Partially funded by INGV and the Italian DPC (DPC-INGV project V4 “Flank”). ERS and ENVISAT SAR data were provided by ESA through the Cat-1 project no. 4532 and the GEO Supersite initiative. The DEM was obtained from the SRTM archive. ERS-1/2 orbits are courtesy of the TU-Delft, The Netherlands. SAR data processing has been done at IREACNR, partially carried out under contract “Volcanic Risk System (SRV)” funded by the Italian Space Agency (ASI).
    Description: Published
    Description: L20311
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: restricted
    Keywords: flank instability ; rift zones ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 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::04.03.09. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 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::04.07.02. 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::04.08.06. 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::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
    Publication Date: 2017-04-04
    Description: The dynamics of the May 18, 1980 lateral blast at Mount St. Helens, Washington (USA), were studied by means of a three-dimensional multiphase flow model. Numerical simulations describe the blast flow as a high-velocity pyroclastic density current generated by a rapid expansion (burst phase, lasting less than 20 s) of a pressurized polydisperse mixture of gas and particles and its subsequent gravitational collapse and propagation over a rugged topography. Model results show good agreement with the observed large-scale behavior of the blast and, in particular, reproduce reasonably well the front advancement velocity and the extent of the inundated area. Detailed analysis of modeled transient and local flow properties supports the view of a blast flow led by a high-speed front (with velocities between 100 and 170 m/s), with a turbulent head relatively depleted in fine particles, and a trailing, sedimenting body. In valleys and topographic lows, pyroclasts accumulate progressively at the base of the current body after the passage of the head, forming a dense basal flow depleted in fines (less than 5 wt.%) with total particle volume fraction exceeding 10−1 in most of the sampled locations. Blocking and diversion of this basal flow by topographic ridges provides the mechanism for progressive current unloading. On ridges, sedimentation occurs in the flow body just behind the current head, but the sedimenting, basal flow is progressively more dilute and enriched in fine particles (up to 40 wt.% in most of the sampled locations). In the regions of intense sedimentation, topographic blocking triggers the elutriation of fine particles through the rise of convective instabilities. Although the model formulation and the numerical vertical accuracy do not allow the direct simulation of the actual deposit compaction, present results provide a consistent, quantitative model able to interpret the observed stratigraphic sequence.
    Description: Published
    Description: B06208
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: restricted
    Keywords: Mount St. Helens ; blast, multiphase flow ; numerical simulations ; pyroclastic density currents ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2017-04-04
    Description: Strombolian eruptions, common at basaltic volcanoes, are mildly explosive events that are driven by a large bubble of magmatic gas (a slug) rising up the conduit and bursting at the surface. Gas overpressure within the bursting slug governs explosion dynamics and vigor and is the main factor controlling associated acoustic and seismic signals. We present a theoretical investigation of slug overpressure based on magma-static and geometric considerations and develop a set of equations that can be used to calculate the overpressure in a slug when it bursts, slug length at burst, and the depth at which the burst process begins. We find that burst overpressure is controlled by two dimensionless parameters: V′, which represents the amount of gas in the slug, and A′, which represents the thickness of the film of magma that falls around the rising slug. Burst overpressure increases nonlinearly as V′ and A′ increase. We consider two eruptive scenarios: (1) the “standard model,” in which magma remains confined to the vent during slug expansion, and (2) the “overflow model,” in which slug expansion is associated with lava effusion, as occasionally observed in the field. We find that slug overpressure is higher for the overflow model by a factor of 1.2–2.4. Applying our model to typical Strombolian eruptions at Stromboli, we find that the transition from passive degassing to explosive bursting occurs for slugs with volume 〉24–230 m3, depending on magma viscosity and conduit diameter, and that at burst, a typical Strombolian slug (with a volume of 100–1000 m3) has an internal gas pressure of 1–5 bars and a length of 13–120 m. We compare model predictions with field data from Stromboli for low-energy “puffers,” mildly explosive Strombolian eruptions, and the violently explosive 5 April 2003 paroxysm. We find that model predictions are consistent with field observations across this broad spectrum of eruptive styles, suggesting a common slug-driven mechanism; we propose that paroxysms are driven by unusually large slugs (large V′).
    Description: Published
    Description: B02206
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: restricted
    Keywords: Stromboli ; Taylor bubble ; basaltic volcanoes ; falling film ; gas slug ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
    Publication Date: 2021-12-06
    Description: We apply a novel computational approach to assess, for the first time, volcanic ash dispersal during the Campanian Ignimbrite (Italy) super-eruption providing insights into eruption dynamics and the impact of this gigantic event. The method uses a 3D time-dependent computational ash dispersion model, a set of wind fields, and more than 100 thickness measurements of the CI tephra deposit. Results reveal that the CI eruption dispersed 250–300 km3 of ash over 3.7 million km2. The injection of such a large quantity of ash (and volatiles) into the atmosphere would have caused a volcanic winter during the Heinrich Event 4, the coldest and driest climatic episode of the Last Glacial period. Fluorine-bearing leachate from the volcanic ash and acid rain would have further affected food sources and severely impacted Late Middle-Early Upper Paleolithic groups in Southern and Eastern Europe.
    Description: Published
    Description: L10310
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: restricted
    Keywords: Campanian Ignimbrire ; Campi Flegrei ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
    Publication Date: 2017-04-04
    Description: The subalkaline rocks outcropping at the Acicastello Castle Rock, Catania, Sicily, and on its abrasion platforms, are related to the oldest Etnean volcanism 500–300 ka; Here, submarine lavas with pillows closely packed onto each other are associated with heterogeneous and poorly sorted volcaniclastic breccia levels with sub-vertical sharp w boundaries. The present-day attitude was previously interpreted as due to a local tilt or to the seaward sliding of the entire eastern Etnean flank , on the assumption of originally horizontal boundaries. On the contrary, our observations do not match the hypothesis of a significantly tilted succession and lead us to conclude that, apart from the strong regional uplift, the present Castle Rock exposure did not suffer any substantial change of its attitude.
    Description: Published
    Description: 209-225
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: pillow-lavas ; volcaniclastic deposits ; hydromagmatic activity ; Mount Etna ; eruption depth ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 21
    Publication Date: 2017-04-04
    Description: We performed measurements using an SO2 imaging camera of the SO2 gas mass emitted during five discrete explosive events on Stromboli volcano on 3 October 2006. The SO2 gas mass released during discrete explosions was 15–40 kg per explosion, producing 3–8% of the total daily SO2 gas emission, demonstrating that in terms of gas flux Strombolian explosions are a second-order phenomenon compared with quiescent degassing. Using the typical gas composition measured with OP-FTIR allows us to determine the total gas mass released during an explosion as 360–960 kg with a volume of 1500–4100 m3 at 1 bar. At the probable source pressure of gas slug formation of 75 MPa this gas amount would occupy a volume equivalent to a sphere with a radius of 0.8–1 m, comparable with estimates of Stromboli's conduit geometry.
    Description: Published
    Description: 395-400
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: magmatic degassing ; remote sensing ; gas imaging ; Stromboli ; Strombolian explosions ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 22
    Publication Date: 2017-04-04
    Description: The main CO2 diffuse degassing structures (DDS) of Stromboli were identified through extensive CO2 soil flux investigations, with 3600 measurements by an accumulation chamber. These DDS extend from the nearby crater area of Pizzo sopra la Fossa (Pizzo) to the coastal area of Pizzillo and are all associated with NE–SW deep fractures, corresponding to the main volcano-tectonic axis of the island, some of which produced flank eruptions in prehistoric times. In each of the four main DDS, a target area was defined covering the zone with the highest CO2 soil flux, where periodic CO2 flux surveys were carried out. The highest CO2 release was observed during the 2007 eruption and high flux values were recorded at both Pizzo and Pizzillo also in moments of high prolonged Strombolian activity (high number of daily explosions observed from the craters and/or high frequency of VLP seismic events). In order to better investigate the rate of diffuse CO2 degassing in relation to volcanic activity, an automatic station hourly measuring CO2 soil flux and environmental parameters (atmospheric T, P and humidity, soil moisture and T, wind speed and direction) was installed in March 2007 at Nel Cannestrà and Rina Grande DDS. Unusual positive correlations were found at Nel Cannestrà between gas flux and SE wind speed and at Rina Grande between gas flux and soil moisture, which are explained by the local conditions, which favour respectively a Venturi effect and the increase in gas flux toward the station during rains. Ten months of continuous recording confirmed the strong influence of environmental conditions on the CO2 soil flux, but statistical data processing made it possible to recognize clear positive anomalies expressing high rates of deep magmatic CO2 degassing. Comparison with seismic data indicates that high CO2 fluxes are apparently correlated with increases in volcanic activity, such as higher explosion frequency and VLP amplitude. Particularly promising is the temporal coincidence of highest recorded flux anomaly with a major explosion that occurred during the observation period. Data confirm that the two continuously monitored DDS are preferentially deep degassing sites, where anomalous increases of CO2 release could represent a geochemical precursor for either high energy explosions from the craters or the opening of flank eruptive fissures that might threaten the village of Stromboli.
    Description: Published
    Description: 231–245
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli volcano ; degassing structures ; diffuse CO2 fluxes ; geochemical volcanic precursors ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 23
    Publication Date: 2012-02-03
    Description: Application of light detection and ranging (LIDAR) technology in volcanology has 7 developed rapidly over the past few years, being extremely useful for the generation 8 of high‐spatial‐resolution digital elevation models and for mapping eruption products. 9 However, LIDAR can also be used to yield detailed information about the dynamics of 10 lava movement, emplacement processes occuring across an active lava flow field, and the 11 volumes involved. Here we present the results of a multitemporal airborne LIDAR survey 12 flown to acquire data for an active flow field separated by time intervals ranging from 13 15 min to 25 h. Overflights were carried out over 2 d during the 2006 eruption of Mt. Etna, 14 Italy, coincident with lava emission from three ephemeral vent zones to feed lava flow in 15 six channels. In total 53 LIDAR images were collected, allowing us to track the volumetric 16 evolution of the entire flow field with temporal resolutions as low as ∼15 min and at a 17 spatial resolution of 〈1 m. This, together with accurate correction for systematic errors, 18 finely tuned DEM‐to‐DEM coregistration and an accurate residual error assessment, 19 permitted the quantification of the volumetric changes occuring across the flow field. We 20 record a characteristic flow emplacement mode, whereby flow front advance and channel 21 construction is fed by a series of volume pulses from the master vent. Volume pulses 22 have a characteristic morphology represented by a wave that moves down the channel 23 modifying existing channel‐levee constructs across the proximal‐medial zone and building 24 new ones in the distal zone. Our high‐resolution multitemporal LIDAR‐derived DEMs 25 allow calculation of the time‐averaged discharge rates associated with such a pulsed flow 26 emplacement regime, with errors under 1% for daily averaged values.
    Description: This work was partially funded by the Italian 930 Dipartimento della Protezione Civile in the frame of the 2007–2009 Agree- 931 ment with Istituto Nazionale di Geofisica e Vulcanologia–INGV. A.F. 932 benefited from the MIUR‐FIRB project “Piattaforma di ricerca multi‐disci- 933 plinare su terremoti e vulcani (AIRPLANE)” n. RBPR05B2ZJ. S.T. 934 benefited from the project FIRB “Sviluppo di nuove tecnologie per la prote- 935 zione e difesa del territorio dai rischi naturali (FUMO)” funded by the Italian 936 Ministero dell’Istruzione, dell’Università e della Ricerca.
    Description: Published
    Description: B11203
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: LIDAR ; lava flow ; Etna ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 24
    Publication Date: 2017-04-04
    Description: Forecasting the time, nature, and impact of future eruptions is difficult at volcanoes such as Mount Etna, in Italy, where eruptions occur from the summit and on the flanks, affecting areas distant from each other. Nonetheless, the identification and quantification of areas at risk from new eruptions are fundamental for mitigating potential human casualties and material damage. Here, we present new results from the application of a methodology to define flexible high‐resolution lava invasion susceptibility maps based on a reliable computational model for simulating lava flows at Etna and on a validation procedure for assessing the correctness of susceptibility mapping in the study area. Furthermore, specific scenarios can be extracted at any time from the simulation database, for land use and civil defense planning in the long term, to quantify, in real time, the impact of an imminent eruption, and to assess the efficiency of protective measures.
    Description: This work was sponsored by the Italian Ministry for Education, University and Research, FIRB project RBAU01RMZ4 “Lava flow simulations by Cellular Automata,” and by the National Civil Defense Department and INGV (National Institute of Geophysics and Volcanology), project V3_6/09 “V3_6 – Etna.”
    Description: Published
    Description: B04203
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: reserved
    Keywords: lava flows ; volcanic hazard ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
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  • 25
    Publication Date: 2012-02-03
    Description: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.
    Description: Volcano deformation may occur under different conditions. To understand how a volcano deforms, as well as relations with magmatic activity, we studied Mt. Etna in detail using interferometric synthetic aperture radar (InSAR) data from 1994 to 2008. From 1994 to 2000, the volcano inflated with a linear behavior. The inflation was accompanied by eastward and westward slip on the eastern and western flanks, respectively. The portions proximal to the summit showed higher inflation rates, whereas the distal portions showed several sectors bounded by faults, in some cases behaving as rigid blocks. From 2000 to 2003, the deformation became nonlinear, especially on the proximal eastern and western flanks, showing marked eastward and westward displacements, respectively. This behavior resulted from the deformation induced by the emplacement of feeder dikes during the 2001 and 2002–2003 eruptions. From 2003 to 2008, the deformation approached linearity again, even though the overall pattern continued to be influenced by the emplacement of the dikes from 2001 to 2002. The eastward velocity on the eastern flank showed a marked asymmetry between the faster sectors to the north and those (largely inactive) to the south. In addition, from 1994 to 2008 part of the volcano base (south, west, and north lower slopes) experienced a consistent trend of uplift on the order of ∼0.5 cm/yr. This study reveals that the flanks of Etna have undergone a complex instability resulting from three main processes. In the long term (103–104 years), the load of the volcano is responsible for the development of a peripheral bulge. In the intermediate term (≤101 years, observed from 1994 to 2000), inflation due to the accumulation of magma induces a moderate and linear uplift and outward slip of the flanks. In the short term (≤1 year, observed from 2001 to 2002), the emplacement of feeder dikes along the NE and south rifts results in a nonlinear, focused, and asymmetric deformation on the eastern and western flanks. Deformation due to flank instability is widespread at Mt. Etna, regardless of volcanic activity, and remains by far the predominant type of deformation on the volcano.
    Description: ESA provided the SAR data (Cat‐1 no. 4532 and GEO Supersite initiative). The DEM was obtained from the SRTM archive, while the ERS‐1/2 orbits are courtesy of the TU‐Delft, The Netherlands. This work was partially funded by INGV and the Italian DPC (DPCINGV project V4 “Flank”), the Italian DPC (under special agreement with IREA‐CNR), and the Italian Space Agency under contract “sistema rischio vulcanico (SRV).” The authors thank Francesco Casu, Paolo Berardino, and Riccardo Lanari for their support and Geoff Wadge and Michael Poland for their helpful and constructive review of the manuscript.
    Description: Published
    Description: B10405
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Flank instability ; InSAR ; volcanoes ; Etna ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 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::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 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::04.07.02. 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::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.04. Instrumentation and techniques of general interest::05.04.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 26
    Publication Date: 2017-04-04
    Description: Forecasting the time, nature and impact of future eruptions is difficult at volcanoes such as Mount Etna, in Italy, where eruptions occur from the summit and on the flanks, affecting areas distant from each other. Nonetheless, the identification and quantification of areas at risk from new eruptions is fundamental for mitigating potential human casualties and material damage. Here, we present new results from the application of a methodology to define flexible high-resolution lava invasion susceptibility maps based on a reliable computational model for simulating lava flows at Etna and on a validation procedure for assessing the correctness of susceptibility mapping in the study area. Furthermore, specific scenarios can be extracted at any time from the simulation database, for land-use and civil defence planning in the long-term, to quantify, in real-time, the impact of an imminent eruption, and to assess the efficiency of protective measures.
    Description: This work was sponsored by the Italian Ministry for Education, University and Research, FIRB project n° RBAU01RMZ4 “Lava flow simulations by Cellular Automata”, and by the National Civil Defence Department and INGV (National Institute of Geophysics and Volcanology), project V3_6/09 “V3_6 – Etna”.
    Description: In press
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: open
    Keywords: lava flows ; Etna ; hazard evaluation ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 27
    Publication Date: 2019-10-10
    Description: Ground deformation is commonly observed at active volcanoes, where it represents a reliable sign of unrest and a potential precursor of eruptive activity. The source of deformation, however, is not always unequivocally constrained. Magma ascent and differentiation are generally involved, but hydrothermal fluids may play a role, due to thermal expansion and pore pressure acting on rocks. The identification of mechanisms driving ground displacement bears important consequences for hazard evaluation. The aim of this work is to evaluate mechanical effects associated with pressurization and heating of hydrothermal fluids. We first simulate the heat and fluid flow driven by the arrival of magmatic fluids from greater depth. Then, we calcu- late the rock deformation arising from simulated pressure and temperature changes within a shallow hydrothermal system. We employ a mathematical model, based on the linear theory of thermo-poro-elasticity and on a system of distributed equivalent forces. Results show that stronger degassing of a magmatic source may cause several centimeters of uplift.
    Description: INGV-DPC Project V1 Unrest
    Description: Published
    Description: 155-161
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: open
    Keywords: Hydrothermal system ; ground deformation ; poro-elasticity ; volcanic unrest ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
    Publication Date: 2017-04-04
    Description: Flank instability is common at volcanoes, even though the subsurface structures, including the depth to a detachment fault, remain poorly constrained. Here, we use a multidisciplinary approach, applicable to most volcanoes, to evaluate the detachment depth of the unstable NE flank of Mt. Etna. InSAR observations of Mount Etna during 1995–2008 show a trapdoor subsidence of the upper NE flank, with a maximum deformation against the NE Rift. The trapdoor tilt was highest in magnitude in 2002–2004, contemporaneous with the maximum rates of eastward slip along the east flank. We explain this deformation as due to a general eastward displacement of the flank, activating a rotational detachment and forming a rollover anticline, the head of which is against the NE Rift. Established 2D rollover construction models, constrained by morphological and structural data, suggest that the east‐dipping detachment below the upper NE flank lies at around 4 km below the surface. This depth is consistent with seismicity that clusters above 2–3 km below sea level. Therefore, the episodically unstable NE flank lies above an east‐dipping rotational detachment confined by the NE Rift and Pernicana Fault. Our approach, which combines short‐term (InSAR) and long‐term (geological) observations, constrains the 3D geometry and kinematics of part of the unstable flank of Etna and may be applicable and effective to understand the deeper structure of volcanoes undergoing flank instability or unrest.
    Description: This work was partially funded by INGV and the DPC‐INGV project “Flank”, and partially by the ASI (SRV project).
    Description: Published
    Description: L16304
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: 3.2. Tettonica attiva
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: flank instability ; fault ; InSAR ; Etna ; rollover ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 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::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 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::04.08.06. 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::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
    Publication Date: 2017-04-04
    Description: Volcanoes deform as a consequence of the rise and storage of magma; once magma reaches a critical pressure, an eruption occurs. However, how the edifice deformation relates to its eruptive behavior is poorly known. Here, we produce a joint interpretation of spaceborne InSAR deformation measurements and volcanic activity at Mt. Etna (Italy), between 1992 and 2006. We distinguish two volcano-tectonic behaviors. Between 1993 and 2000, Etna inflated with a starting deformation rate of 1 cm yr 1 that progressively reduced with time, nearly vanishing between 1998 and 2000; moreover, low-eruptive rate summit eruptions occurred, punctuated by lava fountains. Between 2001 and 2005, Etna deflated, feeding higher-eruptive rate flank eruptions, along with large displacements of the entire East-flank. These two behaviors, we suggest, result from the higher rate of magma stored between 1993 and June 2001, which triggered the emplacement of the dike responsible for the 2001 and 2002–2003 eruptions. Our results clearly show that the joint interpretation of volcano deformation and stored magma rates may be crucial in identifying impending volcanic eruptions.
    Description: This work was partly funded by INGV and the Italian DPC and was supported by ASI, the Preview Project and CRdC-AMRA. DPC-INGV Flank project providing the funds for the publication fees.
    Description: Published
    Description: L02309
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: partially_open
    Keywords: deformation ; eruptions ; Mt. Etna ; eruptive cycle ; InSAR ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 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::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 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::04.08.01. Gases ; 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 ; 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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  • 30
    Publication Date: 2017-04-04
    Description: After the 6 month-long effusive event of 2002-2003, a new lava effusion occurred at Stromboli between 27 February and 2 April 2007. Despite the different durations, approximately the same volume of magma was emitted in both eruptions, in the order of 107 m3 . A paroxysmal eruption occurred at the summit craters in both the 2002–2003 and 2007 episodes, during which a significant amount of low porphyritic (LP), volatile- rich magma was erupted. In both cases, the paroxysm did not interrupt the lava emission. Here, we present compositional data, including texture, mineralogy, chemistry and Sr and Nd isotope ratios of bulk-rock, groundmass and separated minerals of lavas erupted in 2007, together with chemistry and Sr and Nd isotope composition of the pumices emitted during the 15 March paroxysm. As a whole, the lavas have the same texture and chemistry that characterize the highly porphyritic (HP) products usually erupted at Stromboli during normal Strombolian activity and effusive events. Compared to the previous HP products, the 2007 lavas show minor but systematic mineralogical and isotopic variations which are consistent with a modest increase of the magma supply rate of the volcano. Compositional variations during the entire duration of the event are very modest. Glass chemistry changes in lavas erupted in the second half of March can be explained by theminormixing between the volatile-rich LPmagma rising through the shallowmagmatic systemduring the 15 March paroxysm and the degassed residing HP magma. A first conclusion of this study is that there is no compositional evidence supporting major changes in the magma dynamics of the volcano accompanying the effusive activity, as also suggested for the 2002–2003 event. The activity of Stromboli is controlled by a steady state feeding system in which refilling, mixing, degassing and crystallization at shallow level continuously operate,withmodest oscillations in themagma supply rate. Switching between normal Strombolian and effusive activity is related to periods of relatively more vigorous refilling of the shallow system, leading to progressive pressure increase in the upper conduits associated with only minor compositional variations in the erupted products.
    Description: Published
    Description: 255–268
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli volcano ; petrological monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
    Publication Date: 2017-04-04
    Description: Magma flow during explosive volcanic eruptions has been described assuming rigid conduits with simple cylindrical or planar geometries. Here we study the dynamics of explosive volcanic flows to take account of the role of elastic deformation of the conduit influenced by local magmatic pressure. Three cases are investigated: a dyke with elliptical cross-section, a cylindrical conduit and a deep dyke connected to a shallow cylinder. The model CPIUC (Macedonio et al., 2005) was used for simulations and generalized to account for elastic deformations of the conduit cross-section area due to magmatic overpressure. Fragmentation level is typically deeper in a dyke than in a cylinder. For flows in wide dykes pressure at the fragmentation depth can be lower than the surrounding lithostatic pressure by several tens of MPa, indicating that the wall-rocks of the dyke will be unstable, constraining the dyke width and eventually blocking the eruption. On the other hand, when the fragmentation level is shallow the corresponding lithostatic pressure is not large enough to close the dyke and eruptions from wide dykes are possible. The behaviour changes drastically when we assume the conduit is a dyke at depth that evolves to a cylinder near the surface. In this case even very wide dykes can be stable because the fragmentation level moves into the cylindrical region where deformation is negligible.
    Description: Published
    Description: 455–462
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: conduit geometry ; explosive eruption ; elastic effect ; dyke deformation ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2017-04-04
    Description: Eruptions are fed by dikes; therefore, better knowledge of dike propagation is necessary to improve our understanding of how magma is transferred and extruded at volcanoes. This study presents an overview of dike patterns and the factors controlling dike propagation within volcanic edifices. Largely based on published data, three main types of dikes (regional, circumferential and radial) are illustrated and discussed. Dike pattern data from 25 volcanic edifices in different settings are compared to derive semi-quantitative relationships between the topography (relief, shape, height, and presence of sector collapses) of the volcano, tectonic setting (presence of a regional stress field), and mean composition (SiO2 content). The overview demonstrates how dike propagation in a volcano is not a random process; rather, it depends from the following factors (listed in order of importance): the presence of relief, the shape of the edifice and regional tectonic control. We find that taller volcanoes develop longer radial dikes, whose (mainly lateral) propagation is independent of the composition of magma or the aspect ratio of the edifice. Future research, starting from these preliminary evaluations, should be devoted to identifying dike propagation paths and likely locations of vent formation at specific volcanoes, to better aid hazards assessment.
    Description: Partly fundedwith DPC-INGVfunds (LAVAProject).
    Description: Published
    Description: 67–77
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: dikes ; volcanoes ; topography ; tectonic setting ; eruptions ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 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::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 33
    Publication Date: 2017-04-04
    Description: The 2001 eruption represents one of the most studied events both from volcanological and geophysical point of view on Mt. Etna. This eruption was a crucial event in the recent dynamics of the volcano, marking the passage from a period (March 1993–June 2001) of moderate stability with slow, continuous flank sliding and contemporaneous summit eruptions, to a period (July 2001 to present) of dramatically increased flank deformations and flank eruptions. We show new GPS data and high precision relocation of seismicity in order to demonstrate the role of the 2001 intrusive phase in this change of the dynamic regime of the volcano. GPS data consist of two kinematic surveys carried out on 12 July, a few hours before the beginning of the seismic swarm, and on 17 July, just after the onset of eruptive activity. A picture of the spatial distribution of the sin-eruptive seismicity has been obtained using the HypoDD relocation algorithm based on the double-difference (DD) technique. Modeling of GPS measurements reveals a southward motion of the upper southern part of the volcano, driven by a NNW–SSE structure showing mainly left-lateral kinematics. Precise hypocenter location evidences an aseismic zone at about sea level, where the magma upraise was characterized by a much higher velocity and an abrupt westward shift, revealing the existence of a weakened or ductile zone. These results reveal how an intrusion of a dike can severely modify the shallow stress field, triggering significant flank failure. In 2001, the intrusion was driven by a weakened surface, which might correspond to a decollement plane of the portion of the volcano affected by flank instability, inducing an additional stress testified by GPS measurements and seismic data, which led to an acceleration of the sliding flanks.
    Description: This work was funded by the Istituto Nazionale di Geofisica e Vulcanologia and by the Dipartimento per la Protezione Civile (Italy).
    Description: Published
    Description: 78–86
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: stress release ; dike ; volcano-tectonics ; flank instability ; Mt. Etna ; instrumental monitoring ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 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::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 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::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.02. Seismological 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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  • 34
    Publication Date: 2021-12-15
    Description: Eruptive scenarios associated with the possible reactivation of maar-forming events in the Quaternary, ultrapotassic Colli Albani Volcanic District (CAVD) provides implications for volcanic hazard assessment in the densely populated area near Rome. Based on detailed stratigraphy, grain size, componentry, ash morphoscopy and petro-chemical analyses of maar eruption products, along with textural analysis of cored juvenile clasts, we attempt to reconstruct the eruptive dynamics of the Prata Porci and Albano maars, as related to pre- and syn-eruptive interactions between trachybasaltic to K-foiditic feeder magmas and carbonate–silicoclastic and subvolcanic country rocks. Magma volumes in the order of 0.5–3.1×108 m3 were erupted during the monogenetic Prata Porci maar activity and the three eruptive cycles of the Albano multiple maar, originating loose to strongly lithified, wet and dry pyroclastic surge deposits, Strombolian scoria fall horizons and lithic-rich explosion breccias. These deposits contain a wide range of accessory and accidental lithic clasts, with significant vertical stratigraphic variations in the lithic types and abundances. The two maar study cases hold a record of repeated transitions between magmatic (i.e, Strombolian fallout) and hydromagmatic (wet and dry pyroclastic surges) activity styles. Evidence of phreatic explosions, a common precursor of explosive volcanic activity, is only found at the base of the Prata Porci eruptive succession. The quantitative evaluation of the proportions of the different eruptive styles in the stratigraphic record of the two maars, based on magma vs. lithic volume estimates, reveals a prevailing magmatic character in terms of erupted magma volumes despite the hydromagmatic footprint. Different degrees of explosive magma–water interaction were apparently controlled by the different hydrogeological and geological–structural settings. In the Prata Porci case, shifts in the depth of magma fragmentation are proposed to have accompanied eruption style changes. In the Albano case, a deeply dissected geothermal aquifer in peri-caldera setting and variable mass eruption rates were the main controlling factors of repeated shifts in the eruptive style. Finally, textural evidence from cored juvenile clasts and analytical modeling of melt–solid heat transfer indicate that the interacting substrate in the Prata Porci case was at low, uniform temperature (~ 100 °C) as compared to the highly variable temperatures (up to 700–800 °C) inferred for the geothermal system beneath Albano.
    Description: Protezione Civile, Italy 2004–2006 Agreement with Istituto Nazionale di Geofisica e Vulcanologia— INGV, project V3_1
    Description: Published
    Description: 189-202
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: maar ; hydromagmatic eruption ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    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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  • 36
    Publication Date: 2020-12-21
    Description: The lithological and compositional characteristics of eighteen different pyroclastic deposits of Campanian origin, dated between 125 cal ky BP and 22 cal ky BP, were described. The pyroclastic deposits were correlated among different outcrops mainly located on the Apennine slopes that border the southern Campanian Plain. They were grouped in two main stratigraphic and chronologic intervals of regional significance: a) between Pomici di Base (22.03 cal ky BP; Somma–Vesuvius) and Campanian Ignimbrite (39 cal ky BP; Campi Flegrei) eruptions; and b) older than Campanian Ignimbrite eruption. Three new 14C AMS datings support the proposed correlations. Six eruptions were attributed to the Pomici di Base- Campanian Ignimbrite stratigraphic interval, while twelve eruptions are older than Campanian Ignimbrite. Of the studied deposits two originated from Ischia island, five are related to Campi Flegrei, and three to Somma– Vesuvius. Two eruptions have an uncertain correlation with Somma–Vesuvius or Campi Flegrei, while six eruptions remain of uncertain source. Minimum volumes of five eruptions were assessed, ranging between 0.5 km3 and 4 km3. Two of the studied deposits were correlated with Y-3 and X-5 tephra layers, which are widely dispersed in the central Mediterranean area. The new stratigraphic and chronologic data provide an upgraded chrono-stratigraphy for the explosive activity of Neapolitan volcanoes in the period between 125 and 22 cal ky BP.
    Description: Published
    Description: 19–48
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Neapolitan volcanoes ; late Pleistocene ; explosive eruptions ; Somma–Vesuvius ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
    Publication Date: 2021-06-16
    Description: Assessing the residence times of phonolite magmas in the shallow crust contributes to the understanding of explosive volcanic systems. Estimations of that by dating the residence time of a mineral in a melt was difficult in the past, because e.g. of the lack of evidence for the co-genetic character of the crystals dated. Here we present an estimate for the residence time of a phonolite magma feeding the Pomici di Mercato Plinian eruption (8890±90 cal years BP) of Mt. Somma-Vesuvius (Southern Italy), employing U–Th disequilibrium dating of unzoned Ca-rich phenocrystic magmatic garnets. Based on combined textural, geochemical, and Sr- O isotope evidence, these garnets can be identified as co-genetic with their host phonolites. Furthermore, experimental and petrological data suggest that Ca-garnets can be a liquidus phase in highly differentiated phonolite magmas of Mercato. A whole-rock–glass–garnet U–Th isochron gives a crystallisation age for the Ca-rich garnets of 14,400±1100 a (2σ). This implies a Ca-garnet residence time of 5510±1100 years (2σ) in the Mercato phonolite melt prior to eruption and provides one of the first robust estimates of how long explosive phonolite magma has resided in the shallow crust before eruption. Calculations of magma cooling rates and settling velocities of the Ca-garnets confirm that garnet-bearing phonolite can remain liquid and the garnets remain suspended in a magma chamber for as long as 5510 years before the time of eruption. Processes which may have disturbed the U–Th isotope systematic of the samples, such as assimilation, recharge or surface alteration can be ruled out.
    Description: Published
    Description: 293-301
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Uranium ; Thorium ; U–Th isotopes ; Somma-Vesuvius ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
    Publication Date: 2017-04-04
    Description: Morphostructural data derived from Lidar (Light detection and ranging) surveys carried out on Mount Etna in 2005 and 2007 are compared with earlier aerophotogrammetric surveys in 1986 and 1998. These data render an unprecedentedly clear and quantitative image of morphostructural and volumetric changes that have affected the summit area of the volcano in the past two decades and permit the production of a new topographic map. The computed volume gain during the 1986–2007 period amounts to 112 ± 12 106 m3, at a mean annual rate of 5.3 106 m3. The comparison of the various surveys furthermore emphasizes the levels of accuracy and resolution of the different techniques applied. The Lidar technology used in 2007 allows production of high-precision maps in near-real-time, facilitating work concerning environmental hazards such as numerical simulations of, e.g., lava flows.
    Description: Published
    Description: L09305
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: partially_open
    Keywords: Lidar ; Etna ; morphostructural changes ; lava flows ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
    Publication Date: 2017-04-04
    Description: The October 17 to November 5, 1999, eruption of Mount Etna’s Bocca Nuova crater emplaced a V15U106 m3 flow field. The eruption was characterized by 11 paroxysmal events during which intense Strombolian and lava fountain activity fed vigorous channelized PaPa flows at eruption rates of up to 120 m3 s31. Each paroxysm lasted between 75 and 450 min, and was separated by periods of less intense Strombolian activity and less vigorous (610 m3 s31) effusion. Ground-based, satellite- and model-derived volumetric data show that the eruption was characterized by two periods during which eruption rates and cumulative volume showed exponential decay. This is consistent with a scenario whereby the system was depressurized during the first eruptive period (October 17^23), repressurized during an October 24 pause, and then depressurized again during the second period (October 25^28). The imbalance between the erupted and supplied volumes mean that the two periods involved the collection of 1.5^5.7U106 m3 and 1.2^ 3.6U106 m3, respectively, or an increase in the time-averaged supply to 11.6^13.6 m3 s31 and 12.5^14.9 m3 s31. Two models are consistent with the observed episodic fountaining, derived volumetric trends and calculated volume imbalance: a magma collection model and a pulsed supply model. In the former case, depressurization of a shallow reservoir cause the observed volumetric trends and foam collapse at the reservoir roof powers fountaining. In the pulsing case, variations in magma flux account for pressurization^depressurization and supply the excess volume. Increases in rise rate and volatile flux, coupled with rapid exsolution during ascent, trigger fountaining. Limiting equations that define critical foam layer volumes and magma rise rates necessary for Hawaiian-style fountaining favor the latter model.
    Description: Published
    Description: 79-95
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; lava fountaining ; eruption rates ; lava channel ; foam layers ; rise rates ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 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::04.08.07. 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 40
    Publication Date: 2017-04-04
    Description: We present here some criticism to the scientific content of the paper of Milia et al. [2007. The dark nature of Somma-Vesuvius volcano: evidence from the 3.5 ka B.P. Avellino eruption. Quaternary International, 173–174, 57–66] published in Quaternary International. Milia et al. (2007) interpreted seismic lines in the Gulf of Naples (southern Italy), and inferred the presence of deposits from a large debris avalanche which occurred just before the Avellino eruption of Somma-Vesuvius volcano. The authors supported their seismic profile interpretation with on-land stratigraphies and logs. However, we present here different on-land data that demonstrate the inconsistency of the occurrence of any debris avalanche before or after the Avellino eruption, and we provide also an alternative interpretation for the observed seismic facies offshore of Somma-Vesuvius.
    Description: Published
    Description: 102–109
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: open
    Keywords: Somma-Vesuvius volcano ; Avellino eruption ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
    Publication Date: 2017-04-04
    Description: A 350m deep boreholewas drilled in the Colli Albani volcanic district (Central Italy) in order to: understand the shallow crust structure beneath the volcanic complex; characterize the rock physical properties especially through in-situ measurements and, afterward, laboratory experiments; assess the local present-day stress field; install a broad-band seismometer at depth. The borehole is located adjacent to the western rim of the Tuscolano–Artemisio caldera, where several phenomena of unrest recently occurred. In 1989–90 a seismic swarm affected this area and a related uplift was recognized. In addition, high gas concentrations (mainly CO2 and H2S), in aquifers and soils, caused illnesses and casualties among inhabitants and animals in the past. We describe the investigations carried out at the drill site and the results achieved from data analysis.Wire-line drilling produced a complete stratigraphic record of the Quaternary volcanic units down to the Plio–Pleistocene sedimentary sequence and geophysical logs allowed a characterization of the rock physical properties. From a tectonic point of view, data provided by Dipmeter and Borehole Televiewer were used for investigations on the recent and present-day stress field and the results are compared to those available in the literature. In the volcanic units we recognized two main fracture systems, SW and NW dipping. Several faults intersecting the borehole showplaneswith oblique striae, indicating a prevalent strike–slip component of the movement. Finally, borehole breakout analysis defined an active stress field with a ∼E–Woriented minimum horizontal component. At the end of the drilling, a blow-out occurred, due to pressurized fluids trapped into the sandy unit drilled in the last fewmeters of the hole. Sampling these fluids gave an additional value to the borehole, providing information about the deep volcanic circulation and its possible connection to a deep-seated magma chamber. The main results show water with a Na–HCO3 chemistry and the highest salinity ever recognised in the area (Electrical Conductivity=10.12 mS/cm). Stable O and H isotopes reveal ameteoric origin ofwater and the absence of tritium points out a long residence time in the aquifer. Emitted gas is CO2-dominated, with N2 as second most important component. Helium isotopic composition of the gas allows us to estimate a magmatic component ranging in the interval 40–50%, one of the highest in the Colli Albani. Carbon isotopes of CO2 (−0.53‰ vs. PDB) suggest that it could derive partly froma magmatic source and partly by the thermal decarbonation of the carbonatic basement.
    Description: Published
    Description: 225-240
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: scientific drilling ; volcanic stratigraphy ; wireline logs ; fluid geochemistry ; Italy ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 42
    Publication Date: 2017-04-04
    Description: The 2001 eruption represents one of the most studied events both from volcanological and geophysical point of view on Mt. Etna. This eruption was a crucial event in the recent dynamic of the volcano, marking the passage from a period (March 1993 – June 2001) of moderate stability with slow, continuous flank sliding and contemporaneous summit eruptions, to a period (July 2001 to present) of dramatically increased flank deformations and flank eruptions. We show new GPS data and high precision relocation of seismicity in order to demonstrate the role of the 2001 intrusive phase in this change of the dynamic regime of the volcano. GPS data consist of two kinematic surveys carried out on 12 July, a few hours before the beginning of the seismic swarm, and on 17 July, just after the onset of eruptive activity. A picture of the spatial distribution of the sin-eruptive seismicity has been obtained using the HypoDD relocation algorithm based on the double-difference (DD) technique. Modeling of GPS measurements reveal a southward motion of the upper southern part of the volcano, driven by a NNW-SSE structure showing mainly left-lateral kinematics. Precise hypocenter location evidences an aseismic zone at about sea level, where the magma upraise was characterized by a much higher velocity and an abrupt westward shift, revealing the existence of a weakened or ductile zone. These results reveal how an intrusion of a dike can severely modify the shallow stress field, triggering significant flank failure. In 2001, the intrusion was driven by a weakened surface, which might correspond to a decollement plane of the portion of the volcano affected by flank instability, inducing an additional stress testified by GPS measurements and seismic data, which led to an acceleration of the sliding flanks.
    Description: In press
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    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: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: reserved
    Keywords: Stress release ; Dike ; Volcano-tectonics ; Flank instability ; Mount Etna ; Instrumental monitoring ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 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::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 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::04.08.06. 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
    Publication Date: 2017-04-04
    Description: On 27 February 2007, two NE–SW and NNW–SSE dike-fed effusive vents opened to the North (at 650 and 400 m above sea level, asl) of the summit craters at Stromboli, forming a fissure parallel to the inner walls of the Sciara del Fuoco (SdF) sector collapse depression. The formation of these vents was soon followed by rapid subsidence of the summit crater area. This partly obstructed the central conduit, temporarily choking the fissure and increasing the deformation of the upper part of SdF. The reactivation of the NNW–SSE vent and the opening of a new vent located at 500 m asl, fed by a second dike, released the internal pressure and surface deformation ceased. The eruption then continued again from the 400 m vent, after a summit explosion on 15 March, until ending in early April after a progressive decrease of magma output. Repeated NE–SW dike intrusions have occurred in recent years, close to the upper SE limit of the SdF. In that zone, named Bastimento, the eruptive fractures traced the discontinuities that borders the SdF, increasing the risk of triggering new sector collapse. Whereas the NE–SW trending structures lie along the regional volcanostructural trend of the Aeolian arc through Stromboli, the NNW–SSE vents are oblique to this trend and may be controlled by the anomalous stress field within the unstable flank of the SdF. Another fundamental aspect of the 2007 eruption is the collapse of the central conduit, due to the rapid and deep magma drainage linked to the opening of the 400 m vent. The intrusion of dikes and development of flank vents during the 2007 eruption could possibly have triggered catastrophic landslides and related tsunami or eruptive paroxysms, but the opening of new effusive vents released the internal pressures, diminishing the hazard.
    Description: In press
    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: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: 2007 Stromboli eruption ; Dike-fed vent ; Volcano-Tectonics ; Conduit collapse ; Flank instability ; 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::04.07.07. Tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 44
    Publication Date: 2017-04-04
    Description: Three different methodologies were used to measure Radon (222Rn) in soil, based on both passive and active detection system. The first technique consisted of Solid State Nuclear Track Detectors (SSNTD), CR-39 type, and allowed integrated measurements. The second one consisted of a portable device for short time measurements. The last consisted of a continuous measurement device for extended monitoring, placed in selected sites. Soil 222Rn activity was measured together with soil Thoron (220Rn) and soil carbon dioxide (CO2) efflux, and it was compared with the content of radionuclides in the rocks. Two different soil gas horizontal transects were investigated across the Pernicana fault system (NE flank of Mount Etna), from November 2006 to April 2007. The results obtained with the three methodologies are in a general agreement with each other and reflect the tectonic settings of the investigated study area. The lowest 222Rn values were recorded just on the fault plane, and relatively higher values were recorded a few tens of meters from the fault axis on both of its sides. This pattern could be explained as a dilution effect resulting from high rates of soil CO2 efflux. Time variations of 222Rn activity were mostly linked to atmospheric influences, whereas no significant correlation with the volcanic activity was observed. In order to further investigate regional radon distributions, spot measurements were made to identify sites having high Rn emissions that could subsequently be monitored for temporal radon variations.. SSNTD measurements allow for extended-duration monitoring of a relatively large number of sites, although with some loss of temporal resolution due to their long integration time. Continuous monitoring probes are optimal for detailed time monitoring, but because of their expense, they can best be used to complement the information acquired with SSNTD in a network of monitored sites.
    Description: In press
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: Soil Radon and Thoron activity ; soil CO2 efflux ; Pernicana fault system ; Mount Etna ; volcano-tectonic monitoring ; 03. Hydrosphere::03.04. Chemical and biological::03.04.07. Radioactivity and isotopes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 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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  • 45
    Publication Date: 2017-04-04
    Description: During an eruption at the Bocca Nuova, one of the summit craters of Mt. Etna, in October-November 1999 a part of the crater floor near its WNW rim was uplifted to form a dome-shaped feature that consisted of older lava and pyroclastics filling the crater. This endogenous dome grew rapidly over the crater rim, thus being perched precariously over the steep outer slope of the Bocca Nuova, and near-continuous collapse of its steep flanks generated swiftly moving pyroclastic avalanches over a period of several hours. These avalanches advanced at speeds of 10-20 m s-1 and extended up to 0.7 km from their source on top of lavas emplaced immediately before. Their deposits were subsequently covered by lava flows that issued from vents below the front of the dome and from the Bocca Nuova itself. Growth of the dome was caused by the vertical intrusion of magma in the marginal W part of the crater, which deformed and uplifted previously emplaced, still hot and plastically deformable eruptive products filling the crater. The resulting avalanches had all characteristics of pyroclastic flows spawned by collapse of unstable flanks of lava domes, but in this case the magma involved was of mafic (hawaiitic) composition and would have, under normal circumstances, produced fluid lava flows. The formation of the dome and the generation of the pyroclastic avalanches owe their occurrence to the rheological properties of the eruptive products filling the crater, which were transformed into the dome, and to the morphological configuration of the Bocca Nuova and its surroundings. The density contrast between successive erupted products may also have played a role. Although events of this type are to be considered exceptional at Etna, their recurrence might represent a serious hazard to visitors to the summit area.
    Description: Published
    Description: 115-128
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Mt. Etna ; Bocca Nuova ; endogenous lava dome ; pyroclastic avalanches ; magma ascent ; 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::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 46
    Publication Date: 2017-04-04
    Description: Repeated phenomena of flank instability accompanied the 28 December 2002 to 21 July 2003 eruption of Stromboli volcano. The major episodes were two tsunamigenic landslides on 30 December 2002, 2 d after the volcano unrest. After 30 December, sliding processes remodeled the area affected by slope instability.We propose analyses of 565 sliding episodes taking place from December 2002 to February 2003.We try to shed light on their main seismic features and links with the ongoing seismic and volcanic activity using variogram analysis as well. A characterization of the seismic signals in the time and frequency domains is presented for 185 sliding episodes. Their frequency content is between 1 Hz and 7 Hz. On the basis of the dominant peaks and shape of the spectrum, we identify three subclasses of signals, one of which has significant energy below 2 Hz. Low-frequency signatures were also found in the seismic records of the landslides of 30 December, which affected the aerial and submarine northwestern flank of the volcano. Accordingly, we surmise that spectral analysis might provide evidence of sliding phenomena with submarine runouts.We find no evidence of sliding processes induced by earthquakes. Additionally, a negative statistical correlation between sliding episodes and explosion quakes is highlighted by variogram analysis. Variograms indicate a persistent behavior, memory, of the flank instability from 5 to 10 d.We interpret the climax in the occurrence rate of the sliding processes between 24 and 29 January 2003 as the result of favorable conditions to slope instability due to the emplacement of NW-SE aligned, dike-fed vents located near the scarp of the landslide area. Afterward, the stabilizing effect of the lava flows over the northwestern flank of the volcano limited erosive phenomena to the unstable, loose slope not covered by lava.
    Description: This work was supported financially by Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento per la Protezione Civile, project INGV-DPC V4/02.
    Description: Published
    Description: Q04022
    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: JCR Journal
    Description: reserved
    Keywords: rockfalls ; seismicity ; volcanoes ; volcano collapses ; Stromboli ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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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  • 47
    Publication Date: 2017-04-04
    Description: Eruptions are often fed by dikes; therefore, better knowledge of dike propagation is necessary to improve our understanding of how magma is transferred and extruded at volcanoes. This study presents an overview of dike patterns and the factors controlling dike propagation within volcanic edifices. Largely based on published data, three main types of dikes (regional, circumferential and radial) are illustrated and discussed. Dike pattern data from 25 volcanic edifices in different settings are compared to derive semi-quantitative relationships between the topography (relief, shape, height, and presence of sector collapses) of the volcano, tectonic setting (presence of a regional stress field), and mean composition (SiO2 content). The overview demonstrates how dike propagation in a volcano is not a random process; rather, it depends from the following factors (listed in order of importance): the presence of relief, the shape of the edifice and regional tectonic control. We find that taller volcanoes develop longer radial dikes, whose (mainly lateral) propagation is independent of the composition of magma or the aspect ratio of the edifice. Future research, starting from these preliminary evaluations, should be devoted to identifying dike propagation paths and likely locations of vent formation at specific volcanoes, to better aid hazards assessment.
    Description: In press
    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: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: open
    Keywords: dikes ; volcanoes ; topography ; tectonic setting ; eruptions ; 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::04.08.06. 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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  • 48
    Publication Date: 2017-04-04
    Description: Eruptive scenarios associated with the possible reactivation of maar-forming events in the Quaternary, ultrapotassic Colli Albani Volcanic District (CAVD) provides implications for volcanic hazard assessment in the densely populated area near Rome. Based on detailed stratigraphy, grain size, componentry, ash morphoscopy and petro-chemical analyses of maar eruption products, along with textural analysis of cored juvenile clasts, we attempt to reconstruct the eruptive dynamics of the Prata Porci and Albano maars, as related to pre- and syn-eruptive interactions between trachybasaltic to K-foiditic feeder magmas and carbonate–silicoclastic and subvolcanic country rocks. Magma volumes in the order of 0.5–3.1×108 m3 were erupted during the monogenetic Prata Porci maar activity and the three eruptive cycles of the Albano multiple maar, originating loose to strongly lithified, wet and dry pyroclastic surge deposits, Strombolian scoria fall horizons and lithic-rich explosion breccias. These deposits contain a wide range of accessory and accidental lithic clasts, with significant vertical stratigraphic variations in the lithic types and abundances. The two maar study cases hold a record of repeated transitions between magmatic (i.e, Strombolian fallout) and hydromagmatic (wet and dry pyroclastic surges) activity styles. Evidence of phreatic explosions, a common precursor of explosive volcanic activity, is only found at the base of the Prata Porci eruptive succession. The quantitative evaluation of the proportions of the different eruptive styles in the stratigraphic record of the two maars, based on magma vs. lithic volume estimates, reveals a prevailing magmatic character in terms of erupted magma volumes despite the hydromagmatic footprint. Different degrees of explosive magma–water interaction were apparently controlled by the different hydrogeological and geological–structural settings. In the Prata Porci case, shifts in the depth of magma fragmentation are proposed to have accompanied eruption style changes. In the Albano case, a deeply dissected geothermal aquifer in peri-caldera setting and variable mass eruption rates were the main controlling factors of repeated shifts in the eruptive style. Finally, textural evidence from cored juvenile clasts and analytical modeling of melt–solid heat transfer indicate that the interacting substrate in the Prata Porci case was at low, uniform temperature (~ 100 °C) as compared to the highly variable temperatures (up to 700–800 °C) inferred for the geothermal system beneath Albano.
    Description: In press
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Maar ; Colli Albani ; eruptive styles ; explosive activity ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 49
    Publication Date: 2017-04-04
    Description: On 27 February 2007, at 12.49 GMT, a new eruption of Stromboli took place with the effusion of a 15 lava flow from a fracture cutting the flank of the NE cone, which rapidly reached the sea. The eruption 16 had been heralded by an increase in the amplitude of tremor and flank movement since at least the 14th 17 of February. Short-term precursors were an increase in the rate of occurrence of small landslides within 18 the “Sciara del Fuoco” scar on the North-western flank of the volcano. A new effusive vent opened at 19 18.30 GMT on the Sciara del Fuoco at an height of 400 m asl. The new lava emission caused the 20 sudden termination of the summit flow and initiated a period of non-stationary lava outpouring which 21 ended on 2 April, 2007. The eruption has been characterized by a rapid decrease in the eruption rate after the first days and subsequently by episodic pulse increases. On the 15th 22 of March, the increase in 23 lava outpouring, monitored by a thermal camera, heralded by 9 minutes the occurrence of a violent 24 paroxysmal explosion with the formation of an impulsive eruption column and the emission of small 25 pumices mingled with black scoriae. The pumice had a bulk composition similar to that of the lava and 26 of the black scoriae, but with a distinct lower content of phenocrysts. A similar feature has been 27 repeateadly observed during the major explosive paroxysms of Stromboli. Short term precursors of the 28 paroxysm were recorded by strainmeter and tiltmeter stations. The volcano monitoring activity has 29 been made by a joint team of researchers from the INGV sections of Catania, Napoli, Palermo and 30 Rome, along with researchers from the University of Florence, Pisa, Roma Tre, and Palermo. The 31 scientific activity was coordinated by a Synthesis Group made up by the responsibles of the different 32 monitoring techniques of INGV and Universities and by the volcanic experts of Commissione Nazionale Grandi Rischi of the Prime Minister Office (Civil Protection Department). 33 The group made a 34 daily evaluation of the state of the volcano and transmitted its recommendations to the Civil Protection 35 Department (DPC). Several prevention measures were adopted by DPC, the main of which were the 36 evacuation of the coast zone when strong acceleration of the Sciara del Fuoco slope motion (occurred 37 twice) could led to a dangerous tsunami by flank collapse (as last occurred on 30 December 2002) and 38 four days before the 15 March paroxysm when access was prohibited to the part of the volcano above 39 290m asl
    Description: In press
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: open
    Keywords: Stromboli volcano ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 50
    Publication Date: 2017-04-04
    Description: The tectonic escarpments locally known as ‘Timpe’ cut a large sector of the eastern flank of Etna, and allow an ancient volcanic succession dating back to 225 ka to be exposed. Geological and volcanological investigations carried out on this succession have allowed us to recognize relevant angular unconformities and volcanic features which are the remnants of eruptive fissures, as well as important changes in the nature, composition and magmatic affinity of the exposed volcanics. In particular, the recognition in the lower part of the succession of important and unequivocal evidence of ancient eruptive fissures led us to propose a local origin for these volcanics and to revise previous interpretations which attributed their westward-dipping to the progressive tectonic tilting of strata. These elements led us to reinterpret the main features of the volcanic activity occurring since 250 ka BP and their relationship with tectonic structures active in the eastern flank of Etna. We propose a complex paleo-environmental and volcanotectonic evolution of the southeastern flank of Mt. Etna, in which the Timpe fault system played the role of the crustal structure that allowed the rise and eruption of magmas in the above considered time span.
    Description: Published
    Description: 289-306
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Mount Etna ; tectonics ; fisssure eruptions ; columnar basalt ; fault escarpment ; xenoliths ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 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::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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::04.08.07. 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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  • 51
    Publication Date: 2017-04-04
    Description: The 2002–2003 Etna eruption is studied through earthquake distributions and surface fracturing. In September 2002, earthquake-induced surface rupture (sinistral offset 0.48 m) occurred along the E-W striking Pernicana Fault (PF), on the NE flank. In late October, a flank eruption accompanied further ( 0.77 m) surface rupturing, reaching a total sinistral offset of 1.25 m; the deformation then propagated for 18 km eastwards to the coastline (sinistral offset 0.03 m) and southwards, along the NW-SE striking Timpe (dextral offset 0.04 m) and, later, Trecastagni faults (dextral offset 0.035 m). Seismicity (〈4 km bsl) on the E flank accompanied surface fracturing: fault plane solutions indicate an overall ESEWNWextension direction, consistent with ESE slip of the E flank also revealed by ground fractures. A three-stage model of flank slip is proposed: inception (September earthquake), climax (accelerated slip and eruption) and propagation (E and S migration of the deformation).
    Description: Published
    Description: 2286
    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: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: volcano seismology ; surface fracturing ; flank slip ; eruption ; Etna ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 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::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 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::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 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
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  • 52
    Publication Date: 2017-04-04
    Description: We investigated the existence of a fractal law (power law) distribution of size pyroclastic fragments erupted during the fallout phase of the 79 A.D. Plinian eruption at Mt. Vesuvius. In particular, we performed a particle size distribution analysis on 18 white and grey pumice samples collected in six sites distributed in the SW sector of Mt. Vesuvius. Our measurements show that the fragmentation of samples in the investigated range (from 32 mm to 850 μm) follows a power law, guaranteeing the scale invariance of the process. The relationship frequency-size distribution of the fragments is verified independently from the nature (i.e., pumices and lithics) and stratigraphic height of the considered samples in the pyroclastic deposit. Therefore, the fractal fragmentation theory can be indicated for evaluating the relationship between the intensity of fragmentation (fractal dimension D) and eruption energy. In this way the apparent chaotic distribution of the particles in the fallout deposits hides a self-organized complexity revealed by the retrieved power law distribution. We further remark that a key aspect of our analysis is the founded evidence that the fractal dimension of the lithics is systematically greater than that of the pumices.
    Description: Published
    Description: 288–299
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: fragmentation ; power law distribution ; fractal dimension ; scale invariant ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 53
    Publication Date: 2017-04-04
    Description: Public works in progress in the Campanian plain north of Somma- ^ Vesuvius recently encountered the remains 15 of a prehistoric settlement close to the town of Afragola. Rescue excavations brought to light a Bronze Age 16 village partially destroyed and buried by pyroclastic density currents (PDCs) of the Vesuvian Pomici di 17 Avellino eruption (3. ^ 8 14C ka BP) and subsequently sealed by alluvial deposits. Volcanological and rock- 18 ^ magnetic investigations supplemented the excavations. 19 Careful comparison between volcanological and archaeological stratigraphies led to an understanding of the 20 timing of the damage the buildings suffered when they were struck by a series of PDCs. The first engulfed the 21 village, located some 15 km to the north of the inferred vent, and penetrated into the dwellings without 22 causing major damage. The buildings were able to withstand the weak dynamic pressure of the currents and 23 deviate their path, as shown by the magnetic fabric analyses. Some later collapsed under the load of the 24 deposits piled up by successive currents. Stepwise demagnetization of the thermal remanent magnetization 25 (TRM) carried by potsherds embedded in the deposits yields deposition temperatures in the order of 260– 26 ^ 320 °C, fully consistent with those derived from pottery and lithic fragments from other distal and proximal 27 sites. The fairly uniform temperature of the deposits is here ascribed to the lack of pervasive air entrainment 28 into the currents. This, in turn, resulted from the lack of major topographical obstacles along the flat plain. 29 The coupling of structural damage and sedimentological analyses indicates that the currents were not 30 destructive in the Afragola area, but TRM data indicate they were still hot enough to cause death or severe 31 injury to humans and animals. The successful escape of the entire population is apparent from the lack of 32 human remains and from thousands of human footprints on the surface of the deposits left by the first PDCs. 33 People were thus able to walk barefoot across the already emplaced deposits and escape the subsequent 34 PDCs. The rapid cooling of the deposits was probably due to both their thinness and heat dissipation due to 35 condensation of water vapour released in the mixture by magma–water interaction
    Description: In press
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: pyroclastic density current ; Bronze Age ; magnetic fabric ; deposition temperature ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 54
    Publication Date: 2020-02-24
    Description: Measurements of 220Rn and 222Rn activity and of CO2 flux in soil and fumaroles were carried out on Mount Etna volcano in 2005–2006, both in its summit area and along active faults on its flanks. We observe an empirical relationship between (220Rn/222Rn) and CO2 efflux. The higher the flux of CO2, the lower the ratio between 220Rn and 222Rn. Deep sources of gas are characterized by high 222Rn activity and high CO2 efflux, whereas shallow sources are indicated by high 220Rn activity and relatively low CO2 efflux. Excess 220Rn highlights sites of ongoing shallow rock fracturing that could be affected by collapse, as in the case of the rim of an active vent. Depletion both in 220Rn and in CO2 seems to be representative of residual degassing along recently active eruptive vents.
    Description: This work was funded by the Istituto Nazionale di Geofisica e Vulcanologia (S.G., M.N.) and by the Dipartimento per la Protezione Civile (Italy), projects V3_6/28-Etna (M.N.) and V5/08-Diffuse degassing in Italy (S.G.), and NSF EAR 063824101 (K.W.W.S.).
    Description: Published
    Description: Q10001
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: radon ; thoron ; carbon dioxide ; rock stress ; gas transport ; Mount Etna ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
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  • 55
    Publication Date: 2020-02-24
    Description: Preface
    Description: Published
    Description: 77-79
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: Silicate Melt Workshop ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 56
    Publication Date: 2020-03-19
    Description: FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of 8 volcanic ash. The model solves the advection-diffusion-sedimentation (ADS) equa- 9 tion on a structured terrain-following grid using a second-order Finite Differences 10 (FD) explicit scheme. Different parameterizations for the eddy diffusivity tensor 11 and for the particle terminal settling velocities can be used. The code, written 12 in FORTRAN 90, is available in both serial and parallel versions for Windows and 13 Unix/Linux/Mac X Operating Systems (OS). A series of pre- and post-process util- 14 ity programs and OS-dependent scripts to launch them are also included in the 15 FALL3D distribution package. Although the model has been designed to forecast 16 volcanic ash concentration in the atmosphere and ash loading at ground, it can also 17 be used to model the transport of any kind of airborne solid particles. The model 18 inputs are meteorological data, topography, grain-size distribution, shape and den- 19 sity of particles, and mass rate of particle injected into the atmosphere. Optionally, 20 FALL3D can be coupled with the output of the meteorological processor CALMET, a 21 diagnostic model which generates 3-D time-dependent zero-divergence wind fields 22 from mesoscale forecasts incorporating local terrain effects. The FALL3D model can 23 be a tool for short-term ash deposition forecasting and for volcanic fallout hazard 24 assessment. As an example, an application to the 22 July 1998 Etna eruption is also 25 presented.
    Description: Published
    Description: 1334–1342
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: open
    Keywords: volcanic ash ; fallout ; computational model ; FORTRAN code ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
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  • 57
    Publication Date: 2020-01-08
    Description: We present new electron microprobe and Sr-isotope analytical results from mixing experiments using natural volcanic samples. In order to constrain the dynamics of such mixing events, we applied a Taylor– Couette flow, simulating forced convection under very low Reynolds numbers, in a time series ranging from 1 h up to 1 week. The end-member melts derive from samples of the Campanian Ignimbrite (CI), in Italy. The CI is thought to represent a layered reservoir formed in 3 stages: 1) a resident phono-trachytic magma reservoir (end-member A); replenished by 2) a less evolved trachybasaltic–trachytic magma (endmember B of trachytic composition); 3) short-term pre-eruptive mixing in the shallow chamber between a new trachytic and the phono-trachytic resident magmas. Our experiments are motivated by this hypothesis. The two end-members are stirred together, under constant low flow velocity (0.5 rotations per minute). This initially generates single convection cells, which cause progressive homogenization of some major components. This is the case after 1, 4 and 9 h. After 16 h the 87Sr/86Sr-isotopic system is homogenized and the starting compositions are fully mixed. Then separate convection cells and compositional layering for major and minor elements emerged. Based on microprobe measurements of quenched melts (glass) from the 16-hour, 25-hour and 1-week long experiments, we confirm the separation of layers having different densities. This phenomenon is locally complicated by the production of micro-volumes of unmixed melts. Our results support the effectiveness of the interplay between convection and diffusion, enhanced by a double-diffusive–convection-driven differentiation for moderately high-silica magmas under high (nearliquidus) temperatures, attesting that differentiation initiates in the liquidus before the onset of fractional crystallization.
    Description: Published
    Description: 131-145
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Magma mixing ; Experiments ; Major and minor elements ; Advection/diffusion ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 58
    Publication Date: 2021-09-20
    Description: Numerical simulations of column collapse and pyroclastic density current (PDC) scenarios at Vesuvius were carried out using a transient 3D flow model based on multiphase transport laws. The model describes the complex dynamics of the collapse as well as the effects of the 3D topography of the volcano on PDC propagation. Source conditions refer to a medium-scale sub-Plinian event and consider a pressure-balanced jet. Simulation results provide new insights into the complex dynamics of these phenomena. In particular: 1) column collapse can be characterized by different regimes, from incipient collapse to partial or nearly total collapse, thus confirming the possibility of a transitional field of behaviour of the column characterized by the contemporaneous and/or intermittent occurrence of ash fallout and PDCs; 2) the collapse regime can be characterized by its fraction of eruptive mass reaching the ground and generating PDCs; 3) within the range of the investigated source conditions, the propagation and hazard potential of PDCs appear to be directly correlated with the flow-rate of the mass collapsing to the ground, rather than to the collapse height of the column (this finding is in contrast with predictions based on the energy-line concept, which simply correlates the PDC runout and kinetic energy with the collapse height of the column); 4) first-order values of hazard variables associated with PDCs (i.e., dynamic pressure, temperature, airborne ash concentration) can be derived from simulation results, thereby providing initial estimates for the quantification of damage scenarios; 5) for scenarios assuming a location of the central vent coinciding with that of the present Gran Cono, Mount Somma significantly influences the propagation of PDCs, largely reducing their propagation in the northern sector, and diverting mass toward the west and southeast, accentuating runouts and hazard variables for these sectors; 6) the 2D modelling approximation can force an artificial radial propagation of the PDCs since it ignores azimuthal flows produced by real topographies that therefore need to be simulated in fully 3D conditions.
    Description: Published
    Description: 378-396
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Vesuvius ; pyroclastic density current ; column collapse ; numerical simulation ; 3D modelling ; hazard assessment ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 59
    Publication Date: 2017-04-04
    Description: Despite its impact in understanding oceanic crust formation and eruptive styles of related volcanism, magma dynamics at midocean ridges are poorly known. Here, we propose a new method to assess ascent rates of mid-ocean ridge basalt (MORB) magmas, as well as their pre- and sin-eruptive dynamics. It is based on the idea that a rising magma can reach a variable degree of both CO2 supersaturation in melt and kinetic fractionation among noble gases in vesicles in relation to its ascent rate through the crust. To quantify the relationship, we have used a model of multicomponent bubble growth in MORB melts, developed by extending the single-component model of Proussevitch and Sahagian [A.A. Proussevitch, D.L. Sahagian, Dynamics and energetics of bubble growth in magmas: analytical formulation and numerical modeling, J. Geophys. Res. 103 (1998), 18223–18251.] to CO2–He–Ar gas mixtures. After proper parameterization, we have applied it to published suites of data having the required features (glasses from Pito Seamount and mid-Atlantic ridges). Our results highlight that the investigated MORB magmas display very different ranges of ascent rates: slow rises of popping rock forming-magmas that cross the crust (0.01–0.5 m/s), slightly faster rates of energetic effusions (0.1–1 m/s), up to rates of 1–10 m/s which fall on the edge between lava effusion and Hawaiian activity. Inside a single plumbing system, very dissimilar magma dynamics highlight the large differences in compressive stress of the oceanic crust on a small scale. Constraints on how the systems of ridges work, as well as the characteristics of the magmatic source, can also be obtained. Our model shows how measurements of both the dissolved gas concentration in melt and the volatile composition of vesicles in the same sample are crucial in recognizing the kinetic effects and definitively assessing magma dynamics. An effort should be made to correctly set the studied samples in the sequence of volcanic submarine deposits where they are collected. Enhanced knowledge of a number of physical properties of gas-bearing MOR magmas is also required, mainly noble gas diffusivities, to describe multicomponent bubble growth at a higher confidence level.
    Description: Published
    Description: 138-158
    Description: JCR Journal
    Description: reserved
    Keywords: Bubble growth; ; MORB; ; Noble gas; ; Kinetic fractionation; ; Modeling ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 60
    Publication Date: 2017-04-04
    Description: Viscosity of water-bearing float glass (0.03–4.87 wt% H2O) was measured in the temperature range of 573–1523 K and pressure range of 50–500 MPa using a parallel plate viscometer in the high viscosity range and the falling sphere method in the low viscosity range. Melt viscosity depends strongly on temperature and water content, but pressure up to 500 MPa has only minor influence. Consistent with previous studies on aluminosilicate compositions we found that the effect of dissolved water is most pronounced at low water content, but it is still noticeable at high water content. A new model for the calculation of the viscosities as a function of temperature and water content is proposed which describes the experimental data with a standard deviation of 0.22 log units. The depression of the glass tran- sition temperature Tg by dissolved water agrees reasonably well with the prediction by the model of Deubener [J. Deubener, R. Mu¨ ller, H. Behrens, G. Heide, J. Non-Cryst. Solids 330 (2003) 268]. Using water speciation measured by near-infrared spectroscopy we infer that although the effect of OH groups in reducing Tg is larger than that of H2O molecules, the difference in the contribution of both species is smaller than predicted by Deubener et al. (2003). Compared to alkalis and alkaline earth elements the effect of protons on glass fragility is small, mainly because of the relatively low concentration of OH groups (max. 1.5 wt% water dissolved as OH) in the glasses.
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: Glass transition ; Pressure effects ; FTIR measurements ; Alkali silicates ; Silicates ; Soda-lime-silica ; Fragility ; Viscosity ; Water in glass ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 61
    Publication Date: 2017-04-04
    Description: This paper presents and discusses the measurement of permeability of Neapolitan Yellow Tuff (NYT) samples obtained in the framework of a study concerning the phenomenon of bradyseism, i.e. the slow vertical movement of soil, in the Campi Flegrei caldera (Campania—Italy). Measurements have been performed under isothermal, non-isothermal and transient non-isothermal conditions using a specifically designed apparatus. Results of measurements of porosity of different samples are also reported. Experimental results in isothermal conditions show that the volume flux through the samples changes linearly with applied pressure. The values of permeability obtained turn out to be independent of the temperature and pressure gradients applied to the samples. This result is consistent with the fact that the permeability is a characteristic of the porous medium, and as such is not affected by temperature and pressure variation, at least in the range examined. The permeability values measured in our laboratories agree quite well with the ones measured in situ by the Agenzia Generale Italiana Petroli (AGIP) during a geothermal exploration of the Campi Flegrei area in 1980. An interesting, still unexplained phenomenon has been detected during transient phases when both pressure and temperature gradients were applied to the samples. The phenomenon consists in an enhancement of volume flux due to heat flux in the transient phase. The extra volume-flux disappears once the steady temperature gradient is reached.
    Description: Published
    Description: 125-136
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Campi Flegrei ; hydrothermal systems; ; resurgent calderas ; porous media ; hydraulic permeability ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 62
    Publication Date: 2017-04-04
    Description: This paper focuses on the role that hydrothermal systems may play in caldera unrest. Changes in the fluid chemistry, temperature, and discharge rate of hydrothermal systems are commonly detected at the surface during volcanic unrest, as hydrothermal fluids adjust to changing subsurface conditions. Geochemical monitoring is carried out to observe the evolving system conditions. Circulating fluids can also generate signals that affect geophysical parameters monitored at the surface. Effective hazard evaluation requires a proper understanding of unrest phenomena and correct interpretation of their causes. Physical modeling of fluid circulation allows quantification of the evolution of a hydrothermal system, and hence evaluation of the potential role of hydrothermal fluids during caldera unrest. Modeling results can be compared with monitoring data, and then contribute to the interpretation of the recent caldera evolution. This paper: 1) describes the main features of hydrothermal systems; 2) briefly reviews numerical modeling of heat and fluid flow through porous media; 3) highlight the effects of hydrothermal fluids on unrest processes; and 4) describes some model applications to the Phlegrean Fields caldera. Simultaneous modeling of different independent parameters has proved to be a powerful tool for understanding caldera unrest. The results highlight the importance of comprehensive conceptual models that incorporate all the available geochemical and geophysical information, and they also stress the need for high-quality, multi-parameter monitoring and modeling of volcanic activity.
    Description: Accepted
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: open
    Keywords: hydrothermal activity ; caldera unrest ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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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  • 63
    Publication Date: 2017-04-04
    Description: Deep-sea exploration is rapidly improving our understanding of volatiles geochemistry in mid-ocean-ridge igneous products. It is also placing greater constraints on degassing processes of the Earth’s mantle, with the result that degassing models based on vapour–melt equilibrium are no longer able to explain the increasing number of data. In fact, such models force to postulate an upper mantle strongly heterogeneous at any scale, and cannot account for the widespread carbon supersaturation of the recovered igneous products. Here we review the global He–Ar–CO2 dataset of fluid inclusions in mid-ocean-ridge glasses using the framework of advanced modelling of multicomponent bubble growth in magmas. We display that non-equilibrium fractionations among He, Ar and CO2, driven by their different diffusivities in silicate melts, are common in most of the natural conditions of magma decompression and their signature strongly depends on pressure of degassing. Due to the comparable Ar and CO2 diffusivity, magma degassing at low pressure fractionates both the He/Ar and He/CO2 ratio by a similar extent, while the slower CO2 diffusion at high pressure causes early kinetic effects on Ar/CO2 ratio and dramatically changes the degassing path. On this ground, the very different geochemical signatures among suites of data coming from different ridge segments mainly depend on the depth of the magma chamber where the melt was stored. Besides, the variations inside a single suite highlight variable ascent speed and cooling rate of the emplaced lava. The large variations in both the He/CO2 and Ar/CO2 ratios at almost constant He/Ar, displayed in glasses coming from the Mid-Atlantic Ridge 24–30 N segment and the Rodriguez Triple Junction, are therefore interpreted as a high-pressure signature. In contrast, the simultaneous increase in both He/CO2 and He/Ar of the East Pacific Rise, Pito Seamount and South-East Indian Ridge data sets suggests the dominance of low-pressure fractionation, implying that the shallow magma chambers are at a lower depth than those of the Mid- Atlantic Ridge 24–30 N and Rodriguez Triple Junction. Our conclusions support the presence of a relationship between spreading rate and depth of high-temperature zones below ridges, and are consistent with the depth of magma chambers as suggested from seismic studies. Non-equilibrium degassing explains the volatile systematics of mid-ocean-ridge basalts by starting from a single mantle-derived magma, dispensing with the supposed need for heterogeneities in abundance ratios of volatiles in the mantle below oceanic ridges.
    Description: Published
    Description: 1747–1763
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: nonequilibrium degassing ; MORB mantle ; geochemical modeling ; fluid inclusions ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 64
    Publication Date: 2017-04-04
    Description: The FLOWGO thermo-rheological model links heat loss, core cooling, crystallization, rheology and flow dynamics for lava flowing in a channel. We fit this model to laser altimeter (LIDAR) derived channel width data, as well as effusion rate and flow velocity measurements, to produce a best-fit prediction of thermal and rheological conditions for lava flowing in a ~1.6 km long channel active on Mt. Etna (Italy) on 16th September 2004. Using, as a starting condition for the model, the mean channel width over the first 100 m (6 m) and a depth of 1 m we obtain an initial velocity and instantaneous effusion rate of 0.3–0.6 m/s and ~3 m3/s, respectively. This compares with field- and LIDAR-derived values of 0.4 m/s and 1–4 m3/s. The best fit between model-output and LIDAR-measured channel widths comes from a hybrid run in which the proximal section of the channel is characterised by poorly insulated flow and the medial-distal section by well-insulated flow. This best-fit model implies that flow conditions evolve down-channel, where hot crusts on a free flowing channel maximise heat losses across the proximal section, whereas thick, stable, mature crusts of ′a′a clinker reduce heat losses across the medial-distal section. This results in core cooling per unit distance that decreases from ~0.02–0.015°C m−1 across the proximal section, to ~0.005°C m−1 across the medial-distal section. This produces an increase in core viscosity from ~3800 Pa s at the vent to ~8000 Pa s across the distal section.
    Description: Published
    Description: L01301
    Description: 3.6. Fisica del vulcanismo
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Kava Channel ; LIDAR ; thermal modeling ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 65
    Publication Date: 2020-05-29
    Description: In January 2002 Mount Nyiragongo erupted foiditic lavas that covered the Southern volcano flank devastating vast urban areas. Lava flows originated from vents at different heights on the eruptive fissure displayed different velocities, from tens of km/h at the highest vents to slow-advance (0.1–1 km/h) in Goma town several km away from the volcano. To understand the different behavior of lava flows and their threat to the local population, we undertook a multidisciplinary study involving textural and rheological measurements and numerical simulations of heat transfer during magma ascent. We demonstrate that pre-eruptive cooling and syn-eruptive undercooling of magma determined the different rheological behavior of lava flows erupted from vents at diverse heights. Venting at lower altitudes is expected to produce viscous, slowly advancing lavas, although development of fluid, faster flows should be included among possible future eruptive scenarios.
    Description: Published
    Description: L06301
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Nyiragongo volcano ; textural and rheological measurements ; numerical simulations ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 66
    Publication Date: 2020-01-08
    Description: Despite recent advances by means of experiments and high-resolution surveys and the growing understanding of the physical processes before and during volcanic eruptions, duration and type of eruptive activity still remain highly unpredictable. This uncertainty hinders appropriate hazard and associated risk assessment tremendously. In an effort to counter this problem, experimentally generated pyroclasts have been studied by fractal statistics with the aim of evaluating possible relationships between eruption energy and fragmentation efficiency. Rapid decompression experiments have been performed on three differently porous sample sets of the 1990–1995 eruption of Unzen volcano (Japan) at 850 °C and at initial pressure values above the respective fragmentation threshold [U. Kueppers, B. Scheu, O. Spieler, D. B. Dingwell, Fragmentation efficiency of explosive volcanic eruptions: a study of experimentally generated pyroclasts. J. Volcanol. Geotherm. Res. 153 (2006) 125–135.,O. Spieler, B. Kennedy, U. Kueppers, D.B. Dingwell, B. Scheu, J. Taddeucci, The fragmentation threshold of pyroclastic rocks. EPSL 226 (2004) 139–148.]. The size distribution of generated pyroclasts has been studied by fractal fragmentation theory and the fractal dimension of fragmentation (Df), a value quantifying the intensity of fragmentation, has been measured for each sample. Results showthat size distribution of pyroclastic fragments follows a fractal law(i.e. power-law) in the investigated range of fragment sizes, indicating that fragmentation of experimental samples reflects a scale-invariant mechanism. In addition, Df is correlated positively with the potential energy for fragmentation (PEF) while showing a strong influence of the open porosity of the samples. Results obtained in this work indicate that fractal fragmentation theory may allow for quantifying fragmentation processes during explosive volcanic eruptions by calculating the fractal dimension of the size distribution of pyroclasts. It emerges fromthis study that fractal dimension may be utilised as a proxy for estimating the explosivity of volcanic eruptions by analysing their natural pyroclastic deposits.
    Description: Published
    Description: 800-807
    Description: open
    Keywords: volcanic fragmentation ; simulation of eruptions ; explosive energy ; pyroclasts ; fragment size distribution ; fractal fragmentation theory ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 279718 bytes
    Format: application/pdf
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