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  • 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring  (117)
  • 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks  (56)
  • 03. Hydrosphere::03.01. General::03.01.03. Global climate models
  • Elsevier  (134)
  • Elsevier Science Limited  (32)
  • Irkutsk : Ross. Akad. Nauk, Sibirskoe Otd., Inst. Zemnoj Kory
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • Wiley
  • 2010-2014  (69)
  • 2005-2009  (99)
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Publisher
Years
Year
  • 1
    Publication Date: 2021-07-14
    Description: We present the first density model of Stromboli volcano (Aeolian Islands, Italy) obtained by simultaneously inverting land-based (543) and sea-surface (327) relative gravity data. Modern positioning technology, a 1 × 1 m digital elevation model, and a 15 × 15m bathymetric model made it possible to obtain a detailed 3-D density model through an iteratively reweighted smoothness-constrained least-squares inversion that explained the land-based gravity data to 0.09 mGal and the sea-surface data to 5 mGal. Our inverse formulation avoids introducing any assumptions about density magnitudes. At 125 m depth from the land surface, the inferred mean density of the island is 2380 kg m−3, with corresponding 2.5 and 97.5 percentiles of 2200 and 2530 kg m−3. This density range covers the rock densities of new and previously published samples of Paleostromboli I, Vancori, Neostromboli and San Bartolo lava flows. High-density anomalies in the central and southern part of the island can be related to two main degassing faults crossing the island (N41 and N64) that are interpreted as preferential regions of dyke intrusions. In addition, two low-density anomalies are found in the northeastern part and in the summit area of the island. These anomalies seem to be geographically related with past paroxysmal explosive phreato-magmatic events that have played important roles in the evolution of Stromboli Island by forming the Scari caldera and the Neostromboli crater, respectively. © 2014 Elsevier B.V. All rights reserved.
    Description: Published
    Description: 58–69
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Stromboli, Gravity, Inversion, Geophysics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2017-04-04
    Description: We present a review of our work on data acquired by GEOSTAR-class (GEophysical and Oceanographic STation for Abyssal Research) observatories deployed at three EMSO (European Multidisciplinary Seafloor and water-column Observatory; http://www.emso-eu.org) sites in southern European waters where strong geo-hazards are present: the Western Iberian Margin, the Western Ionian Sea, the Marmara Sea, and the Marsili basin in the Tyrrhenian Sea. A procedure for multiparameter data quality control is described. Then we explain why the seafloor is an interesting observation point for geophysical parameters and how it differs from land sites. We consider four interesting geophysical phenomena found at the EMSO sites that are related to geo-hazard. In the first case, we show how unknown seismicity and landslides in the Western Ionian Sea were identified and roughly localised through a single-sensor analysis based on the seismometer. In the second case, we concentrate on the problem of near-coast tsunami generation and describe a Tsunami Early Warning Detection (TEWD) system, tested in the Western Iberian Margin and currently operating in real time at the Western Ionian site. In the third case, we consider two large volcanoes in the central Mediterranean area, Mt. Etna and the Marsili seamount. Signals from the seismometer and gravimeter recorded at the seafloor at 2100 m b.s.l. show various phases of Mt. Etna's 2002–2003 eruption. For the less-known Marsili we illustrate how several indicators coming from different sensors point to hydrothermal activity. A vector magnetometer at the two volcanic sites helps identify the magnetic lithospheric depth. In the fourth and final case, we present a multiparameter analysis which was focused on finding possible correlations between methane seepage and seismic energy release in the Gulf of Izmit (Marmara Sea).
    Description: Published
    Description: 12–30
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: JCR Journal
    Description: restricted
    Keywords: European Seas ; Geophysical measurements ; Multiparameter seafloor and water-column observatories ; Data quality analysis ; Geo-hazard ; Tsunami early detection ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
    Publication Date: 2017-04-04
    Description: The shallow thermal aquifer at Vulcano Island is strongly affected by deep volcanic fluids. The most significant variations were observed during the 1989–1996 crisis due to a large input of steam and acidic gases from depth. Besides chemical variations related to the input of deep fluids, the record of the water-table elevation at monitored wells has provided remarkable insights into the pressure conditions of the volcano-hydrothermal system. After the pressure drop due to the extensive vaporization of the hydrothermal aquifer, occurred after 1993, the volcano-hydrothermal system has been re-pressurized since 2001, probably because of the contribution of volatiles from the hydrothermal-magmatic source. The increase in fluid pressure may have caused reopening of fractures (which had self-seated during the previous period of cooling) and the onset of a phase of higher vapor output in the fumarole field later in 2004. The fracture opening would have promoted further vapor separation from the deep fluid reservoir (hypothesized at 0.5–1.5 km depth) and finally the drainage of S-rich fluids into the shallow thermal aquifer (found out at few tens of meters of depth). The monitoring of both the water chemistry and the water-table elevation provides insights into the eventual pressurization of the volcano-hydrothermal system that precedes the fracture opening and the extensive drainage of deep fluids. The findings of this study could represent crucial information about the stability of the volcano edifice, and lead to reliable techniques for determining the risk of or even predicting phreatic explosions.
    Description: Published
    Description: 70-80
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Hydrothermal system ; Vulcano Island ; Fluid pressure ; Thermal wells ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    Publication Date: 2017-04-04
    Description: El Barronal complex consists of a succession of andesite lavas and andesite volcaniclastic facies interbeddedwith carbonate and siliciclastic sedimentary rocks. Carbonate and siliciclastic rocks were deposited in a shallow- marine environment during periods of volcanic quiescence. Lavas consist of an inner coherent core grading out- ward into hyaloclastite brecciamade of dense clasts that in turn grade into hyaloclastite brecciamade of vesicular clasts, in massive to layered zones. Volcaniclastic facies contain clasts produced during explosive eruptions and reworked clasts from sources above wave base. Volcaniclastic facies were deposited from cold granular flows with different grain size populations. Stratigraphy and facies architecture at El Barronal suggest that a succession of several discrete eruptive events occurred with a similar cyclic pattern made of an initial explosive phase followed by effusive emplacement of lavas, in turn followed by a period of quiescence of volcanic activity. Hyaloclastic fragmentation of magma took place in the final stages of lava emplacement, allowing only for local disorganization of the jigsaw-fit texture.
    Description: Published
    Description: 210-222
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: N/A or not JCR
    Description: restricted
    Keywords: Facies model; Hyaloclastite; Vesicular carapace; Explosive subaqueous volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publication Date: 2021-12-13
    Description: Volcanic lake research boosted after lethal gas burst occurred at Lake Nyos (Cameroon) in 1986, a limnic rather than a volcanic event. This led to the foundation of the IAVCEI-Commission on Volcanic Lakes, which grew out into a multi-disciplinary scientific community since the 1990s. We here introduce the first data base of volcanic lakes VOLADA, containing 474 lakes, a number that, in our opinion, is surprisingly high. VOLADA could become an interactive, open-access working tool where our community can rely on in the future. Many of the compiled lakes were almost unknown, or at least unstudied to date, whereas there are acidic crater lakes topping active magmat- ic–hydrothermal systems that are continuously or discontinuously monitored, providing useful information for volcanic surveillance (e.g., Ruapehu, Yugama, Poás). Nyos-type lakes, i.e. those hosted in quiescent volcanoes and characterized by significant gas accumulation in bottom waters, are potentially hazardous. These lakes tend to remain stably stratified in tropical and sub-tropical climates (meromictic), leading to long-term build- up of gas, which can be released after a trigger. Some of the unstudied lakes are possibly in the latter situation. Acidic crater lakes are easily recognized as active, whereas Nyos-type lakes can only be recognized as potentially hazardous if bottom waters are investigated, a less obvious operation. In this review, research strategies are lined out, especially for the “active crater lakes”. We make suggestions for monitoring frequency based on the principle of the “residence time dependent monitoring time window”. A complementary, multi-disciplinary (geochemis- try, geophysics, limnology, statistics) approach is considered to provide new ideas, which can be the bases for fu- ture volcanic lake monitoring. More profound deterministic knowledge (e.g., precursory signals for phreatic eruptions, or lake roll-over events) should not only serve to enhance conceptual models of single lakes, but also serve as input parameters in probabilistic approaches. After more than 25 years of pioneering studies on rather few lakes (~20% of all), the scientific community should be challenged to study the many poorly studied volcanic lakes, in order to better constrain the related hazards.
    Description: Published
    Description: 78-97
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Volcanic lakes ; Active crater lakes ; Nyos-type lakes ; Monitoring ; Residence time dependent monitoring time window ; Hazard forecasting ; VOLADA data base ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publication Date: 2021-07-14
    Description: New data on the ancient landscape of Naples (southern Italy) during the middle and late Holocene from geo-archaeological excavations associated with public transport works were used to reconstruct the hill and coastal environment to the west of the ancient Graeco-Roman polis, where remains of human settlements date to the late Neolithic. The rich stratigraphic and archaeological records that emerged from the digs and from previous boreholes were measured and analysed by combining sedimentary facies analysis, tephrostratigraphy and archaeological data. Between the 5th and 4th millennia BP, a rocky profile with a wave-cut platform cutting across pyroclastites emplaced from the surrounding volcanoes was predominant in the coastal landscape. During the 3rd millennium BP, this rocky coast was progressively replaced by a sandy littoral environment primarily due to marine deposition, with a coastline located some hundred meters inland with respect to the modern one. The sedimentary record of the Greek and Roman periods indicates short-term fluctuations of the coastline, leading to the establishment of a backshore environment towards the end of the 6th century AD, when prograding river mouths and lobes of debris flows contributed to the advancing trend of the shoreline. The frequent archaeological remains from these periods indicate a stable settled area since Roman times. The shoreline was still subject to short-lived fluctuations between the 12th and 16th centuries, and attained its present position during the modern era with man-made reshaping of its profile. The construction of Relative Sea Level curves for two coastal sites reveals that the persistence of the foreshore environment in the Naples coastal strip during the 5th and 4th millennia BP was controlled by the counterbalancing effect of either the concurrent eustatic sea level rise or subsidence. On the other hand, the morpho-stratigraphic record for the last two millennia shows a significant correlation between sedimentation rate and settlement history, accounting for the dominant role of the anthropogenic forcing-factor in late Holocene landscape history. In particular, land mismanagement during Late Antiquity seems to have triggered a slope disequilibrium phase, exacerbating soil erosion and increasing the sediment accumulation rate in both foothill and coastal areas. Nonetheless, the environmental changes of the Chiaia coast during the last 2000 years clearly show volcanicetectonic perturbations influencing coastline development up to the modern era.
    Description: Published
    Description: 107-119
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.10. Storia ed archeologia applicate alle Scienze della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: study ; Naples coastline ; the last 6000 years ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 7
    Publication Date: 2017-04-04
    Description: This study assessed the use of a H2 fuel cell as an H2-selective sensor for volcano monitoring. The resolution, repeatability, and cross-sensitivity of the sensor were investigated and evaluated under known laboratory conditions. A tailor-made device was developed and used for continuously monitoring H2 and CO2 at Mt Etna throughout 2009 and 2010. The temporal variations of both parameters were strongly correlated with the evolution of the volcanic activity during the monitoring period. In particular, the CO2 flux exhibited long-term variations, while H2 exhibited pulses immediately before the explosive activity that occurred at Mt Etna during 2010.
    Description: Published
    Description: 41–51
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Soil CO2 flux ; H2 monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 8
    Publication Date: 2017-04-04
    Description: Fumarole thermal monitoring is a useful tool in the evaluation of volcanic activity, since temperatures strongly relate to the upward flux of magmatic volatiles. Once depurated from meteorological noise, their variations can reflect permeability changes due to crustal stress dynamics eventually associated to seismic activity. In this work, we discuss a fumarole temperature record acquired in the period September 2009–May 2012 at Vulcano island (Italy), during which changes of volcanic state, local seismic activity and teleseisms occurred. Apart from positive thermal anomalies driven by increments in volcanic activity, we observed 3 episodes at least of concurrence between tectonic earthquakes and fumarole temperature increments, with particular reference to the local August 16th, 2010 Lipari earthquake, the March 11th, 2011 Sendai–Honshu (Japan) earthquake and a seismic swarm occurred along the Tindari-Letojanni fault in July–August 2011. We interpreted the seismic-related anomalies as ‘‘crustal fluid transients’’, i.e. signals of volcanogenic vapour flow variations induced by stress-induced permeability changes. From this perspective fumarolic activity can be considered as a tracer of geodynamic instability but, since seismic and volcanic phenomena are in mutual cause-effect relationships, a multidisciplinary observation system is mandatory for correctly addressing thermal data interpretation.
    Description: Accordo Quadro DPC-INGV 2012-21, Convenzione C, 2012,Progetto V3, Task 3, WP13, UR2
    Description: Published
    Description: 160-169
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Crustal transient ; Fumarole temperature ; Seismic activity ; Stress field ; Teleseism ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2017-04-04
    Description: The continuous monitoring shows short term dynamics and allows multidisciplinary comparisons. Sharp increases and trending variations were recorded in fumarole temperatures. The trends highlighted by punctual monitoring characterized the main fumaroles. A new phase of increasing temperature begun after the year 2001 at the rim fumaroles.
    Description: The exhalation activity at the La Fossa cone (Vulcano Island, Aeolian Archipelago, Italy) has been ongoing for more than 1 century. Many of the monitored geochemical and geophysical parameters have showed transient variations of energy release. The time-series analyses of fumarole temperatures presented in this paper enabled the sequence of observations to be defined and information from different monitoring stations to be integrated. The motion of fluids feeding the fumaroles of the La Fossa cone is driven by the thermal and kinetic energies that balance the seismic and volcanic forces active in the region, and the temperatures of the fumaroles reflect the local response of the hydrothermal system to these forces. During a 14-year period of observation, from 1998 to 2012, fumarole temperatures showed various trends but also cyclic variations characterized by sharp increases. The repetition of these variations during periods with different trends indicates that no physical variation occurred from the hydrothermal source to the surface during the analyzed period, and after each periodic geochemical crisis the previous thermal conditions were restored. Although the continuous monitoring of hightemperature fumaroles was limited to only a few sites, the observed trends characterized the most important fumaroles in the area of Vulcano Island. An evaluation of thermal-energy release based on these spatially discrete measurements would be a speculative exercise in thermodynamics, but the analyses of the recorded data represent a step forward in interpreting the signals from ongoing volcanic activity and in assessing the seismic risk. © 2013 Elsevier B.V. All rights reserved.
    Description: INGV-DPC project
    Description: Published
    Description: 150-163
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: temperature, fumarole, time series, monitoring, geochemistry, volcano ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2017-04-04
    Description: Archaeological and volcanological studies conducted in the Naples area have revealed that numerous high-intensity explosive eruptions that occurred in the past 10 ka caused damage and victims in the human communities living in the plain surrounding the Neapolitan volcanoes. These catastrophic events were interspersed by hundred to thousand year long periods of quiescence, usually exceeding a human life-time. During the Early Bronze Age in particular, the Campania Plain was densely inhabited due to favourable climatic conditions and soil fertility. The archaeological and volcanological investigation of the sequences found in archaeological excavations has permitted the detailed reconstruction of the effects of eruptions and deposition mechanisms of their products on settlements. This paper discusses the example of Nola- Palma Campania during a most interesting, though poorly known, period of activity bracketed by the Vesuvian Pomici di Avellino (Early Bronze Age) and Pollena (AD 472) Plinian eruptions. Through this timespan the Plainwas variably inhabited, crossed by long-lived roads and subject to agricultural exploitation. Eruptions caused significant breaks in the occupation of the area, but also maintained the plain’s extraordinary fertility. During this period, at least eight other eruptions occurred: the Pomici di Pompei Plinian event (AD 79), two sub-Plinian to phreato-Plinian events, and five violent Strombolian to Vulcanian events. Thin and poorly developed to thicker and mature palaeosols or erosional unconformities separate the various pyroclastic deposits. Almost all the eruptions and related phenomena interacted with human settlements in the Campania Plain, and in their sequences many traces of the displacement of people during the eruptions may be seen, as well as land reclamation and re-utilization soon afterwards. Despite the various kinds of hazard posed by volcanic and related phenomena, humans nevertheless found good reasons for settlement in the Campania Plain and flourished there. A multidisciplinary approach has yielded detailed information regarding the evolution of the area and the effects of eruptions on settlements. These data are of paramount importance for an improved understanding of past events and in evaluating the hazard of eruptions and related phenomena.
    Description: Published
    Description: 132-141
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.10. Storia ed archeologia applicate alle Scienze della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: stratigrafy ; volcanology ; archaeology ; volcanic hazard ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 11
    Publication Date: 2017-04-04
    Description: Herein we report on the chemical and isotopic (C, H, O, and He) compositions of the fluids from La Fossa crater fumaroles of Vulcano from 1999 to 2010. Consistent with records obtained since the end of the 1980s, our data show that the geochemical features of the fumarole system have experienced several episodes of remarkable change, each lasting no more than a few months. Typical signatures of these short-term anomalies are large increments in CO2, N2, and He concentrations, coupled to increased 13C/12C isotopic ratios, but their meaning remains widely debated. Within a model of fumarolic fluids based on mixing between hydrothermal and magmatic endmembers, we have developed a novel approach to constrain chemical (He/ CO2 and N2/He) and isotopic (13C/12C, D/H, and 3He/4He) ratios of the magmatic endmember during the short-term anomalies. Although much of the geochemical variability in fumaroles results from changes in mixing proportions, the magmatic fluid unquestionably shows significant variations in time. The magmatic He/CO2, N2/He, 13C/12C, and 3He/4He values throughout 1988–1996 differed from those feeding the anomaly at the end of 2004. Early clues of the new magmatic fluid appeared in 1998–1999, far from any short-term anomaly, whereas new and old magmatic fluids coexisted after 2004. We quantitatively prove that the detected geochemical changes are consistent with the degassing path of a magma having a latitic composition, and suggest the presence of two magma ponding levels at slightly different pressures, where bubble–melt decoupling can occur. The different He-isotope compositions at these levels suggest low hydraulic connectivity typical of a complex reservoir with dike and sill structures. In this framework, the short-term geochemical anomalies are probably due to gas accumulation at the top of magma bodies followed by massive escape, or activation of new degassing levels in the reservoir, for which the stress field almost certainly plays a key role. Such a scenario explains the observed increases in both fumarole output and shallow high-frequency seismicity (due to increased pore pressure) during the anomalies, while being consistent with the concomitant absence of any deep seismicity or ground deformation, eventually related to magma movement.
    Description: Published
    Description: 158-178
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: fumarole geochemistry ; magma degassing ; thermodynamic modeling ; noble gas geochemistry ; carbon isotopes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 12
    Publication Date: 2020-02-24
    Description: The island of Ischia is an active volcanic field, whose activity dates back to more than 150 ka. From Neolithic times it experienced a complex history of human colonization and volcanic eruptions that destroyed settlements and drove away the population. Recent archaeological and volcanological research has demonstrated that humans have periodically had to face volcanic and related hazardous phenomena since at least the Greek foundation of Pithekoussai (8th century BC). During the 5th century BC a telluric event is reported by the historian Strabo to have caused the abandonment of a Syracusan military outpost on the island. In the volcanological literature the Ischia Porto Tephra eruption has been identified as the most likely culprit. The eruption formed a crater lake in the north-eastern corner of the island and emplaced a poorly dispersed pyroclastic deposit, composed of a sequence of magmatic and phreatomagmatic scoria- and pumice-fallout beds, interlayered with minor pyroclastic density current deposits. Recent excavations furnished clear evidence of the impact of this eruption on a settlement located on S. Pietro Hill, to the east of Ischia’s harbour. The archaeological finds include mounds of building materials, pieces of decorative terracotta panels and a few terracotta antefix fragments. The spatial distribution of the material found, the presence of stacks of tiles and other building materials and the absence of any structural remains, suggest that this was a building site for the construction of a temple. As written sources confirm, although the site and the military garrison were abandoned, the colony survived.
    Description: Published
    Description: 142-152
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.10. Storia ed archeologia applicate alle Scienze della Terra
    Description: JCR Journal
    Description: open
    Keywords: Ischia ; Volcanology ; Archaeology ; Eruption impact ; Resilience ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 13
    Publication Date: 2017-04-04
    Description: Herein, we present a method for continuous measurement of soil CO2 flux that is completely new and distinct from existing instruments. The foremost difference is that instead of using an infrared gas analyser (IRGA), the new device measures soil CO2 flux by means of a simple pressure sensor, measuring pressure transients inside a closed polymeric tube inserted into the soil. This allows continuous measurements even in soil placed in environments that could potentially damage IRGA. In addition, due to the innovative operating principle, measurements of soil CO2 flux can be effortlessly performed also in strongly harsh weather conditions. Theoretical equations were derived for calculating soil CO2 flux solely using measured transient values. The reliability of the equations was rigorously tested with a variety of experiments. Continuous measurements over four months, acquired in a high-emission area on the Island of Vulcano, compared favourably with the data obtained using an established method.
    Description: Published
    Description: 102-109
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: restricted
    Keywords: Soil CO2 flux measurements ; Continuous monitoring ; Methods of measurement ; Polymeric membranes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 14
    Publication Date: 2017-04-04
    Description: We present the first chlorine isotope compositional data for gases and lavas from Mount Etna (Italy), and to our knowledge, of active Mediterranean volcanism. We investigated lavas erupted and gases discharged during 2008-2011 from a high-temperature fumarole (HT; 〉300°C) and plume gases from both North East and Central Craters. Most of the samples vary in a narrow range of chlorine isotope composition (37Cl values ≈ 0 ± 0.7‰) with gases partially overlapping with rocks. Only HT gases sampled in 2009 have been clearly affected by secondary processes (37Cl values 〉 15.9‰), resulting in partial removal of chlorine and isotopic fractionation producing a 37Cl enrichment in the residual gaseous HCl. These secondary processes also affect, although to a lesser extent, plume gases from North East Crater (NEC). Although post-magmatic processes are able to modify the chlorine isotope composition, 37Cl values are not affected by magma degassing for residual fractions ≥ 0.3 in the melt, or any effect is within our data variability. Finally, 37Cl values and Cl/K ratios of magmatic chlorine constrain the Etnean source to be compatible with depleted mantle (DMM) contaminated by altered oceanic crust (AOC), in agreement with indications from more common isotopic tracers of mantle processes.
    Description: Published
    Description: 134-142
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Mount Etna ; chlorine isotope ; plume ; fumarole ; degassing ; mantle source ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 15
    Publication Date: 2017-04-04
    Description: On 13 May 2008, an eruption began at Mt. Etna from an eruptive fissure that opened on the upper eastern flank of the volcano. During 12-13 May, 157 infrasonic events, together with the related seismic transients, were collected. We carried out several analyses to obtain dominant frequencies, pseudospectrograms, peak-to-peak amplitudes, source locations and time lags between infrasonic and seismic events. Spectra of the infrasonic events show two main spectral peaks in the frequency bands ~0.4-0.7 Hz and 1.5-2.0 Hz, respectively. Both infrasonic and seismic events were separately located below the North-East Crater, where no eruptive activity was observed. Moreover, significant changes in infrasound spectral content, as well as in the infrasonic-seismic lags, were found a few hours before the beginning of the eruption. On the basis of the collected information the infrasound source mechanism was modelled as a superposition of pipe and Helmholtz resonance, also leading to outline the geometry of the shallower portion of the North-East Crater plumbing system. The occurrence of these seismo-infrasonic events together with other geological and geophysical evidences, led us to inferring a direct link between North-East Crater activity and the eruptive fissure. Further, based on variations over time of both spectral features and seismicinfrasonic time lag, shallowing phenomena of the free magma column inside North-East Crater conduit were hypothesized. Such an uprise of magma was likely caused by a pressure increase inside the plumbing system occurring before the beginning of the 2008-2009 eruption.
    Description: Published
    Description: 53-68
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: open
    Keywords: infrasound ; Helmholtz resonator ; plumbing system geometry ; seismo-acoustic studies ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
    Publication Date: 2017-04-04
    Description: In this paper we present the first data of temperature continuously recorded in two fumarole fields (designated VOR and HOR) located in the summit area of Mount Etna volcano (Italy). The time series embraces two distinct periods: (1) October 2007 to November 2009, during which an effusive eruption occurred from May 2008 to July 2009, and (2) November 2011 to June 2012, characterized by the occurrence of strong paroxysms (fire fountains and lava flow). The analysis of the temperature signal in both the time and frequency domains, and its comparison with meteorological observations allowed us to separate the exogenous influences from the effects of variations in the activity state of the volcano. The acquired data were weakly affected by seasonal cycles of the air temperature and strongly affected by the rainfall. Optimization of site conditions (i.e., sensor depth and soil permeability) markedly reduced meteorological disturbances. The distance from the main degassing and/or eruptive fractures was crucial to maximizing the probability of the technical survival of the monitoring apparatus, which was seriously affected by the emission of acidic gases, tephra fallout, and lava flows. Apart from the exogenous influences, the most appreciable variation was observed at VOR, where a huge increase in fumarole temperature was detected immediately after the onset of the 2008–2009 eruption. Such an anomalous increase was attributed to the rapid ascent of magma feeding the eruptive fracture. Another abrupt increase in temperature was recorded at HOR in March and April 2012. During this period the frequency of paroxysm occurrence increased markedly, and this led us to hypothesize that the thermal anomaly was due to the intrusion of a new batch of magma in the conduits of the southeast crater. Medium- to long-term monitoring (weeks to months) of fumarole temperatures revealed variations that were attributed to pressurization/depressurization phases of the shallow volcanic system, which varied between the various monitored sectors of the volcano. Our observations suggest that continuous monitoring of fumarole temperature can give useful information about the activity of Mount Etna. Moreover, due to the complexity of its shallow plumbing system, we conclude that the monitoring systems should be extended to cover the entire fumarole network of the summit area.
    Description: Published
    Description: 12-20
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Continuous monitoring ; Mount Etna ; Fumarole temperature ; Meteorological parameters ; Volcanic Degassing ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
    Publication Date: 2022-05-04
    Description: This study reports the first crystal chemical database resulting from a detailed structural investigation of trioctahedral micas found in xenolithic ejecta produced during the AD 1631, 1872 and 1944 eruptions, three explosive episodes of recent volcanic period of Vesuvius volcano (Southern Italy). Three xenolith types were selected: metamorphic/metasomatic skarns, pyrometamorphic/hydrothermally altered nodules and mafic cumulates. They are related to different magma chemistry and effusive styles: from sub-plinian and most evolved (AD 1631 eruption) to violent strombolian with medium evolution degree (AD 1872 eruption) to vulcanian-effusive, least evolved (AD 1944 eruption) event, respectively. Both xenoliths and micas were investigated employing multiple techniques: the xenoliths were characterized by X-ray fluorescence, inductively-coupled plasma-mass spectrometry, optical microscopy, X-ray powder diffraction, and quantitative energy-dispersive microanalysis; the micas were studied by electron probe microanalysis and single crystal X-ray diffraction. The mica-bearing xenoliths showvariable texture and mineralogical assemblage, clearly related to their different origin. Based on the major oxide chemistry, only one xenolithic sample falls in the skarn compositional field fromthe Somma-Vesuvius literature, some fall close to the skarns and cumulate fields, others plot close to the syenite/foidolite/essexite field. A subgroup of the selected ejecta does not fall or approach any of the compositional fields. Trace and rare earth element patterns show some petrological affinity between studied xenoliths and erupted magmas with typical Eu, Ta and Nb negative anomalies. Strongly depleted patterns were detected for the 1631 metamorphic/metasomatic skarns xenoliths. Three distinct mica groups were distinguished: 1) Mg-, Al-rich, low Ti-bearing, low to moderate F-bearing varieties (1631 xenolith), 2) Al-moderate, F- and Mg-rich, Ti-, Fe-poor varieties (1872 xenolith), and 3) Al-, Ti- and Fe-rich, F-poor phases (1944 xenolith). All the analyzed mica crystals are 1Mpolytypes with the expected space group C2/m. Micas from xenoliths of the 1631 Vesuvius eruption are phlogopites characterized by a combination of low extent of oxy-type and variable extent OH−→F− substitutions, as testified by the range of F concentration (from ~0.20 to 0.80 apfu). Micas from xenoliths of the 1872 Vesuvius eruption exhibit structural peculiarities typical of fluorophlogopites, i.e. OH−→F− substitution is predominant. Micas from the xenolith of the 1944 Vesuvius eruption display features typical of oxy-substituted micas. The variability of the crystal chemical features of the studied micas is consistentwith the remarkable variation of their host rocks. Micas from1631 nodules are related to metasomatic, skarn-type environment, deriving from the metamorphosed wall-rocks hosting the magma reservoir. The fluorophlogopites from the 1872 xenoliths testify for strongly dehydrated environmental conditions compared to those of the 1631 and 1944 hosts. Finally, magma storage condition at depth, associated to a decreasing aH2O may have promoted major oxy-type substitutions in 1944 biotites.
    Description: Published
    Description: 84–97
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 5.3. TTC - Banche dati vulcanologiche
    Description: JCR Journal
    Description: restricted
    Keywords: phlogopite ; Crystal chemistry ; Vesuvius ; petrogenesis ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2020-11-30
    Description: Mafic phenocrysts from selected products of the last 4 ka volcanic activity at Mt. Vesuvius were investigated for their chemical and O-isotope composition, as a proxy for primary magmas feeding the system. 18O/16O ratios of studied Mg-rich olivines suggest that near-primary shoshonitic to tephritic melts experienced a flux of sedimentary carbonate-derived CO2, representing the early process of magma contamination in the roots of the volcanic structure. Bulk carbonate assimilation (physical digestion) mainly occurred in the shallow crust, strongly influencing magma chamber evolution. On a petrological and geochemical basis the effects of bulk sedimentary carbonate digestion on the chemical composition of the near-primary melts are resolved from those of carbonate-released CO2 fluxed into magma. An important outcome of this process lies in the effect of external CO2 in changing the overall volatile solubility of the magma, enhancing the ability of Vesuvius mafic magmas to rapidly rise and explosively erupt at the surface.
    Description: Published
    Description: 84-95
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: stable-isotope ; magma geochemistry ; CO2-degassing ; Vesuvius ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
    Publication Date: 2021-06-30
    Description: Continental intraplate volcanoes, such as Erebus volcano, Antarctica, are associated with extensional tectonics, mantle upwelling and high heat flow. Typically, erupted magmas are alkaline and rich in volatiles (especially CO2), inherited from low degrees of partial melting of mantle sources. We examine the degassing of the magmatic system at Erebus volcano using melt inclusion data and high temporal resolution open-path Fourier transform infrared (FTIR) spectroscopic measurements of gas emissions from the active lava lake. Remarkably different gas signatures are associated with passive and explosive gas emissions, representative of volatile contents and redox conditions that reveal contrasting shallow and deep degassing sources. We show that this unexpected degassing signature provides a unique probe for magma differentiation and transfer of CO2-rich oxidised fluids from the mantle to the surface, and evaluate how these processes operate in time and space. Extensive crystallisation driven by CO2 fluxing is responsible for isobaric fractionation of parental basanite magmas close to their source depth. Magma deeper than 4 kbar equilibrates under vapour-buffered conditions. At shallower depths, CO2-rich fluids accumulate and are then released either via convection-driven, open-system gas loss or as closed-system slugs that ascend and result in Strombolian eruptions in the lava lake. The open-system gases have a reduced state (below the QFM buffer) whereas the closed-system gases preserve their deep oxidised signatures (close to the NNO buffer).
    Description: Published
    Description: 261–271
    Description: JCR Journal
    Description: restricted
    Keywords: CO2 fluxing ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
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    Elsevier Science Limited
    In:  Supplementary data associated with this article can be found in the online version, at http://dx.doi.org/10.1016/j.jvolgeores.2012.08. 013.
    Publication Date: 2017-04-04
    Description: A pilot GIS-based system has been implemented for the assessment and analysis of hazard related to active faults affecting the eastern and southern flanks of Mt. Etna. The system structure was developed in ArcGis® environment and consists of different thematic datasets that include spatially-referenced arc-features and associated database. Arc-type features, georeferenced into WGS84 Ellipsoid UTM zone 33 Projection, represent the five main fault systems that develop in the analysed region. The backbone of the GIS-based system is constituted by the large amount of information which was collected from the literature and then stored and properly geocoded in a digital database. This consists of thirty five alpha-numeric fields which include all fault parameters available from literature such us location, kinematics, landform, slip rate, etc. Although the system has been implemented according to the most common procedures used by GIS developer, the architecture and content of the database represent a pilot backbone for digital storing of fault parameters, providing a powerful tool in modelling hazard related to the active tectonics of Mt. Etna. The database collects, organises and shares all scientific currently available information about the active faults of the volcano. Furthermore, thanks to the strong effort spent on defining the fields of the database, the structure proposed in this paper is open to the collection of further data coming from future improvements in the knowledge of the fault systems. By layering additional user-specific geographic information and managing the proposed database (topological querying) a great diversity of hazard and vulnerability maps can be produced by the user. This is a proposal of a backbone for a comprehensive geographical database of fault systems, universally applicable to other sites.
    Description: Published
    Description: 170-186
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 5.5. TTC - Sistema Informativo Territoriale
    Description: JCR Journal
    Description: reserved
    Keywords: GIS-based system ; Hazard assessment ; Volcano-tectonics ; Flank dynamics ; Georeferenced arc-features ; Active fault database ; 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::04.04.06. 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::04.07.02. 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 ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 21
    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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  • 22
    Publication Date: 2017-04-03
    Description: A geologically reasonable working hypothesis is proposed for the lithology of the basement underlying the Campi Flegrei caldera in the ca. 4–8 km depth range. In most current geophysical modeling, this portion of crust is interpreted as composed of Meso-Cenozoic carbonate rocks, underlain by a ca. 1 km thick sill of partially molten rock, thought to be a main magma reservoir. Shallower magma reservoirs likely occur in the 3–4 km depth range. However, the lack of carbonate lithics in any Campi Flegrei caldera volcanic rocks does not support the hypothesis of a limestone basement. Considering the major caldera-forming eruptions, which generated widespread and voluminous ignimbrites during late Quaternary times, including the Campanian Ignimbrite and Neapolitan Yellow Tuff eruptions, the total volume of trachytic to phonolitic ejected magma is conservatively estimated at not less than 350 km3. Results of least-squared mass-balance calculations suggest that this evolved magma formed through fractional crystallization from at least 2500 km3 of parent shoshonitic magma, in turn derived from even more voluminous, more mafic, K-basaltic magma. Calculations suggest that shoshonitic magma, likely emplaced at ca. 8 km depth, must have crystallized about 2100 km3 of solid material, dominated by alkali-feldspar and plagioclase, with a slightly lower amount of mafic minerals, during its route toward shallower magma reservoirs, before feeding the Campi Flegrei large-volume eruptions. The calculated volume of cumulate material, likely syenitic in composition at least in its upper portions, is more than enough to completely fill the basement volume in the 4–8 km depth range beneath the Campi Flegrei caldera, estimated at ca. 1250 km3. Thus, it is proposed that the basement underlying the Campi Flegrei caldera below 4 km is composed mostly of crystalline igneous rocks, as for many large calderas worldwide. Syenite sensu lato would meet physical properties requirements for geophysical data interpretations, explain some geochemical and isotopic features of the past 15 ka volcanics, and justify the carbon isotopic composition of fumaroles at the Campi Flegrei caldera. This implies that Meso-Cenozoic limestones, if still present today beneath the Campi Flegrei caldera, no longer constitute significant portions of its basement.
    Description: Published
    Description: 91–98
    Description: JCR Journal
    Description: restricted
    Keywords: Campi Flegrei caldera ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 23
    Publication Date: 2017-04-04
    Description: In this paper, we report four years of soil CO2 emission data measured monthly at 130 sites in two peripheral areas of Mt Etna Volcano that are well known for their high discharge rates of volcanic gas. We remove the influence of atmospheric parameters, and by means of statistical analyses, we (i) demonstrate that variations in CO2 emissions are due mainly to CO2 of a deep origin and (ii) quantify the total amounts of CO2 derived from a deep magma source. Periods of anomalous deep degassing are identified in both areas. A comparison of the timing of these anomalies and geophysical data indicates that the periods of anomalous degassing can be mostly ascribed to intrusions of fresh magma into the Etna plumbing system, which is in agreement with many previous works. Based on the existing literature, we formulate an interpretative framework of magma migration within the plumbing system, consistent with temporal trends in the observed anomalies. Finally, we reconstruct the processes of recent magma ascent at Mt Etna based on our interpretative framework, published geophysical data, and records of volcanic activity.
    Description: Published
    Description: 218-227
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Soil CO2 flux ; Mt Etna ; Volcanic activity ; Magma transfer ; 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::04.08.06. Volcano monitoring
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  • 24
    Publication Date: 2017-04-04
    Description: Imaging rocks in three-dimensions through X-ray microtomography enables routine visualization of structures in samples, which can be spatially resolved down to the sub-micron scale. Although X-ray tomography has been applied in biomedical research and clinical settings for decades, it has only recently been applied to studies of rocks, and few geoscientists realize its value and potential. This contribution provides an introduction to the principles and techniques of X-ray microtomography to the study of igneous rock textures as well as reviewing the current state of the art. We hope that this short review will encourage more geoscientists to apply X-ray microtomography in their research and that this will lead to new insights into the processes that occur in magmatic (as well as other geological) systems.
    Description: Published
    Description: 262-276
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: restricted
    Keywords: X-ray microtomography ; Rock textures ; Three-dimensional imaging and analysis ; Crystal and vesicle size distributions ; Lattice-Boltzmann simulation ; Permeability ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
    Publication Date: 2017-04-04
    Description: Using Etna as a case study location, we examine the balance between the volume of magma supplied to the shallow volcanic system (using ground-based SO2 data) and the volume erupted (using satellite thermal data). We do this for three eruptions of Mt. Etna (Italy) during 2002 to 2006. We find that, during the three eruptions, 2.3×107 m3 or 24% of the degassed volume remained unerupted. However, variations in the degree of partitioning between supplied (Vsupply) and erupted (Verupt) magma occur within individual eruptions over the time scales of days. Consequently, we define and quantify three types of partitioning. In the first case, VsupplybVerupt, i.e. more lava is erupted than is supplied. In such a case previously degassed magma is erupted or magma can rise faster than it is able to degas, as occurred during the open phases of the 2002–2003 and 2004–2005 eruptions, respectively. In the second case, VsupplyNVerupt, i.e. less lava is erupted than is supplied. In such a case, magma can erupt in an explosive manner, as occurred during Phase II of the 2002–2003 eruption, or remain within or below the edifice. In the third case, Vsupply=Verupt, i.e. all supplied magma is erupted. During 2002–2006, over a total of 280 days of eruptive activity, this balancing case applied to 50% of the time.
    Description: Published
    Description: 47-53
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; thermal remote sensing ; SO2 flux ; Effusive eruption ; mass balance ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 26
    Publication Date: 2017-04-04
    Description: In recent years, progress in geographic information systems (GIS) and remote sensing techniques have allowed the mapping and studying of lava flows in unprecedented detail. A composite GIS technique is introduced to obtain high resolution boundaries of lava flow fields. This technique is mainly based on the processing of LIDAR-derived maps and digital elevation models (DEMs). The probabilistic code DOWNFLOW is then used to simulate eight large flow fields formed at Mount Etna in the last 25 years. Thanks to the collection of 6 DEMs representing Mount Etna at different times from 1986 to 2007, simulated outputs are obtained by running the DOWNFLOW code over pre-emplacement topographies. Simulation outputs are compared with the boundaries of the actual flow fields obtained here or derived from the existing literature. Although the selected fields formed in accordance with different emplacement mechanisms, flowed on different zones of the volcano over different topographies and were fed by different lava supplies of different durations, DOWNFLOW yields results close to the actual flow fields in all the cases considered. This outcome is noteworthy because DOWNFLOW has been applied by adopting a default calibration, without any specific tuning for the new cases considered here. This extensive testing proves that, if the pre-emplacement topography is available, DOWNFLOW yields a realistic simulation of a future lava flow based solely on a knowledge of the vent position. In comparison with deterministic codes, which require accurate knowledge of a large number of input parameters, DOWNFLOW turns out to be simple, fast and undemanding, proving to be ideal for systematic hazard and risk analyses.
    Description: Published
    Description: 27-39
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 5.5. TTC - Sistema Informativo Territoriale
    Description: JCR Journal
    Description: reserved
    Keywords: LIDAR ; lava flow field ; lava flow simulation ; Digital elevation model ; Mount Etna ; 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
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  • 27
    Publication Date: 2017-04-04
    Description: In the texture analysis of volcanic rocks, the preferred orientation of the constituents can provide useful information for the interpretation of the processes involved in the rock formation. We present here a new data analysis technique, based on X-ray microtomography measurements and on shape preferred orientation analysis, to obtain the orientation distribution functions of the constituents of volcanic rocks. This procedure proved to be very suitable for volcanic samples, where diffraction-based techniques, developed for crystallographic preferred orientation studies, are of limited utilization, in addition to the fact that they cannot provide any information about vesicles or bubbles. Moreover the analysis performed directly in three dimensions (3D) overcomes the problems that usually occur when employing stereological methods for the analysis of the images obtained via microscopy-based techniques. In this study, two scoriae (from Stromboli and Etna) and a tube pumice (from Campi Flegrei) were measured via X-ray microtomography and then the resulting volumes were analyzed following the proposed procedure. Results highlight little preferred orientation for the vesicles in the two scoria samples, whereas the pumice shows a marked preferred orientation. Crystals (also divided by mineral species) were taken into account as well and in the two scoria samples there is no crystal preferred orientation, in contrast with the pumice, where crystal preferred orientation features are very similar to the ones found for the vesicles. Overall we found strong differences in preferred orientation: weak for vesicles in scoriae, showing an axial symmetry with the axis parallel to the elongation axis of the sample, and a stronger and more complex orientation texture in the pumice sample for both crystals and vesicles. The promising results obtained suggest that this procedure is potentially very useful for the analysis of preferred orientation in volcanic rocks and geomaterials in general.
    Description: Published
    Description: 83-95
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: X-ray computed microtomography ; preferred orientation ; texture analysis ; volcanic scoria ; synchrotron X-rays ; pumice ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 28
    Publication Date: 2017-04-04
    Description: Ambrym is one of the most actively erupting basaltic volcanoes in the Vanuatu island arc. Scoria clasts collected from a fallout deposit in the inner terrace of its Benbow active crater were analyzed through series of synchrotron X-ray computed microtomographic experiments, as well as permeability measurements and simulations. Our goal was to reconstruct and visualize scoria textures in 3D and to quantify vesicularity, permeability, vesicle sizes and distributions in order to understand how gas moves in and out of Ambrym basaltic magma. We find that vesicle size distributions in the volume range between ~ 103 and 1010 μm3 define two scoria classes. Vesicle size distributions in the low-to-moderately (0.44–0.67) vesicular samples can be fit by power laws with an exponent of 1 ± 0.2; distributions in the highly vesicular (0.86–0.88) samples can be fit by power laws with a higher exponent (1.4 to 1.7), as well as by exponential fits. Highly vesicular samples exhibit a very pronounced large vesicle, consisting of networks of smaller, interconnected vesicles, that is more than three orders of magnitude larger in volume than all other vesicles in each distribution. This type of vesicle is not found in the low-to-moderately vesicular samples. In addition, vesicle number density negatively correlates with vesicularity: less vesicular samples have the highest number density and vice versa, and contain far more numerous small-to-medium-sized vesicles than highly vesicular samples. Measured and calculated viscous (Darcian) permeabilities overlap in the range 10− 13 and 10− 9 m2, with higher values in the more vesicular samples. We ascribe these differences in the textural and physical properties of the scoria clasts to their derivation from distinct magma portions in the conduit that were driven by convective overturn and underwent different vesiculation histories and gas transport dynamics. Comparing basaltic scoria clasts from Ambrym to those from mild explosive activity at Stromboli volcano (Italy) reveals that differences in their vesicle size distributions may result from the influence of different crystal contents and shapes on the vesiculation and permeability of the respective magmas. Finally, we highlight how rheological properties have a fundamental role in determining the degassing behaviour of basaltic magma at Ambrym and other volcanoes in general.
    Description: Published
    Description: 55-64
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: restricted
    Keywords: Ambrym ; Basaltic scoria ; 3D X-ray micro-tomography analysis ; Volcanic degassing ; Magma convection ; Crystal effect ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
    Publication Date: 2017-04-04
    Description: The 15 March 2007 Vulcanian paroxysm at Stromboli volcano was recorded by several instruments that allowed description of the eruptive sequence and unravelling the processes in the upper feeding system. Among the devices installed on the island, two borehole strainmeters recorded unique signals not fully explored before. Here we present an analysis of these signals together with the time-lapse images from a monitoring system comprising both infrared and visual cameras. The two strainmeter signals display an initial phase of pressure growth in the feeding system lasting ~2 min. This is followed by 25 s of low-amplitude oscillations of the two signals, that we interpret as a strong step-like overpressure building up in the uppermost conduit by the gas-rich magma accumulating below a thick pile of rock produced by crater rim collapses. This overpressure caused shaking of the ground, and triggered a number of small landslides of the inner crater rim recorded by the monitoring cameras. When the plug obstructing the crater was removed by the initial Vulcanian blast, the two strainmeter signals showed opposite sign, compatible with a depressurizing source at ~1.5 km depth, at the junction between the intermediate and shallow feeding system inferred by previous studies. The sudden depressurization accompanying the Vulcanian blast caused an oscillation of the source composed by three cycles of about 20 sec each with a decreasing amplitude, as well recorded by the strainmeters. The visible effect of this behaviour was the initial Vulcanian blast and a 2-3 km high eruptive column followed by two lava fountainings displaying decreasing intensity and height. To our knowledge, this is the first time that such a behaviour was observed on an open conduit volcano.
    Description: Published
    Description: 249-256
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: restricted
    Keywords: Stromboli volcano ; paroxysmal explosions ; shallow plumbing system ; borehole strainmeters ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 30
    Publication Date: 2017-04-04
    Description: Continuous seismic monitoring plays a key role in the surveillance of the Mt. Etna volcano. Besides earthquakes, which often herald eruptive episodes, the persistent background signal, known as volcanic tremor, provides important information on the volcano status. Changes in the regimes of activity are usually concurrent with variations in tremor characteristics. As continuous recording leads rapidly to the accumulation of large amounts of data, parameter extraction and automated processing become crucial. We propose techniques of unsupervised classification and present a software, named KKAnalysis, developed for this purpose. Essentials of KKAnalysis are demonstrated on tremor data recorded on Mt. Etna during various states of volcanic activity encountered in 2007 and 2008. KKAnalysis is based on MATLAB and combines various unsupervised pattern recognition techniques, in particular self-organizing maps (SOM) and cluster analysis. An early software version was successfully applied to seismic signals recorded on Mt. Etna during the eruption in 2001. Since each situation may require different configurations, we designed KKAnalysis with a specific GUI allowing users to easily modify parameters. All results are given graphically, in screen plots and metafiles (MATLAB and TIF format), as well as in alphanumeric form. The synoptic visualization of results from SOM and cluster analysis facilitates an immediate inspection. The potential of this representation is demonstrated by focusing on data recorded during a flank eruption on May 13, 2008. Changes of tremor characteristics can be clearly identified at a very early stage, well before enhanced volcanic activity becomes visible in the time series. At the same time, data reduction to less than 1% of the original amount is achieved, which facilitates interpretation and storage of the essential information. Running the program in a typical configuration requires computing time less than 1 min, allowing an on-line application for early warning purposes at INGV–Sezione di Catania
    Description: Published
    Description: 953-961
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 5.6. TTC - Attività di Sala Operativa
    Description: JCR Journal
    Description: reserved
    Keywords: Self-Organizing Map ; Cluster Analysis ; K-means ; Fuzzy C-means ; Volcano Seismology ; Volcano Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
    Publication Date: 2017-04-04
    Description: At Stromboli volcano, Italy, continuous seismic monitoring and periodic, visual observations of volcanic activity for surveillance purposes began in the mid-1980s. Since 1985, two eruptions have occurred, one lasting from December, 1985 until April, 1986, and one in May, 1993. There have also been two small overflows, in 1990 and 1994. Since these episodes of lava effusion, the persistent Strombolian activity of the volcano has had several fluctuations during the past 15 years. Some episodes climaxed in powerful explosions. According to seismic records, these paroxysms consisted of a variable number of explosion quakes in rapid succession (i.e. from tens of seconds to a few minutes), associated with a notable increment in the amplitude of volcanic tremor. Throughout these episodes - which are called explosive sequences - lapilli, fragments of old rock, and bombs of varying dimensions were ejected, affecting an area greater than the crater terrace where the active craters are located. In this article, we describe the explosive sequences recorded at Stromboli between 1985 and 1999. We provide a characterization in terms of reduced displacement and duration for nine episodes occurring in 1998 and 1999. Their reduced displacements range from 15 to 124 cm2; their durations are between 6 and 18 min. We find no change in the frequency content of the seismic signal several minutes before and during the sequences. Considering medium- to long-term behavior, the spectral amplitude of the seismic signal decreases or has low values over several months preceding the occurrence of the paroxysms. This feature is common to 20 of the 22 explosive sequences, and is indicative of internal conditions that periodically characterize the feeder. We surmise that the paroxysms are the result of the partial obstruction of the volcanic conduit when the magma column is low or dropping. The onset of the explosive sequence, causing the sudden removal of the material which forms the obstruction, would trigger a sudden depressurization of the conduit and the rapid rise of magma from depth.
    Description: Published
    Description: 137-150
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; Paroxysms ; Seismicity ; Volcanoes ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2017-04-04
    Description: A 4-year geochemical survey of some fumaroles at the Voragine summit crater of Mt Etna was performed in combination with synchronous monitoring of peripheral gas emissions at the base of the volcano. This was the first geochemical study at Mt Etna to have included the abundances of Ar, He, and C isotopes. Once the effects of postmagmatic shallow processes were identified and quantitatively removed, the He–Ar–CO2 systematics of the Voragine crater fumaroles and peripheral gas emissions described the same degassing path. Combining the carbon-isotope composition with information about noble gases provided evidence that the crater fumaroles are fed from a two-endmember mixture composed of a deep member coming from pressures between 200 and 400 MPa (depending on time), and a shallower one exsolved at 130 MPa. Similar mixing processes probably also occur in gases from peripheral vents. The simultaneous assessment of d13CCO2 and He/Ar values of crater fumaroles over time has identified simple changes in the mixing proportion between the two endmembers and, moreover, periods during which the exsolution pressure of the deep fluid increased. These periods seem to be linked to pre-eruptive phases of the volcano. The identified open-system degassing processes are indicative of efficient bubble–melt decoupling at depth, whereas the mixing process requires a convective transfer of the deeply exsolved fluids toward shallower levels of magma where further vapor is exsolved. In agreement with the most recent geophysical and petrological data from Mt Etna, these observations allow inferences about a deep portion of the plumbing system (5 to 12 km b.s.l.), comprising sill-like reservoirs connected by small vertical structures, and a main reservoir at 2–3 km b.s.l. that is probably fluxed by magmatic volatiles. 2012 Elsevier Ltd. All rights reserved.
    Description: Published
    Description: 380-394
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: gas geochemistry, isotopes, degassing, modelling ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
    Publication Date: 2017-04-04
    Description: We analyzed crater SO2 fluxes from Mt Etna, together with soil CO2 effluxes from the volcano's flanks, in the period from 2001 to 2005. Between the 2001 and 2002–2003 eruptions, persistently low values of both parameters suggest that no new gas-rich magma was accumulating at shallow depth (b5 km) within Etna's central conduit, whereas very high SO2 sin-eruptive fluxes during the two eruptions indicated sudden decompression of an un-degassed magma rising along newly-formed eccentric conduits. In November 2003, soil CO2 data indicate migration of gas-rich magma from deep (〉10 km) to shallow (b5 km) portions of the feeding conduits, preceded by an increase in crater SO2 fluxes. A similar behavior was observed also during and after the following 2004–2005 eruption. This degassing style matches a period of increased structural instability of the volcanic edifice caused by acceleration of spreading that affected both its eastern and southern flanks. Spreading could have triggered progressively deeper depressurization in the central conduit, inducing release of the more soluble gas (SO2) first, and then of CO2, contrary to what was observed before the 2001 eruption. This suggests that the edifice has depressurized, promoting ascent of fresh-magma and increasing permeability favouring release of CO2 flux. By integrating geochemical and structural data, previous degassing models developed at Mt. Etna have been updated to advance the understanding of eruptive events that occurred in recent years.
    Description: This work was funded by grants from the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and from the Dipartimento per la Protezione Civile (Italy).
    Description: Published
    Description: 90-97
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    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: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Geochemical modeling ; volcano monitoring ; volcanic gases ; Tectonics and magmatism ; flank collapse ; 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::04.04. 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::04.07.05. 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::04.08.04. Thermodynamics ; 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::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 34
    Publication Date: 2017-04-04
    Description: The impacts of natural atmospheric variability and anthropogenic climate change on the spatial distribution, seasonality, structure, and productivity of North Pacific plankton groups are investigated by means of an Earth System Model (ESM) that contains a plankton model with variable stoichiometry. The ESM is forced with observed greenhouse gases for the 20th century and with the Intergovernmental Panel on Climate Change A1B Emission Scenario for the 21st century. The impacts of the two main modes of variability – connected with the Aleutian Low (AL) strength and with the North Pacific Oscillation (NPO) – are considered. When the AL is strong, primary productivity and chlorophyll concentrations are higher in the central Pacific, the seasonality of plankton is enhanced, and the classical grazing chain is stimulated, whereas in the Alaskan Gyre the model simulates a chlorophyll decrease and a shift toward smaller phytoplankton species. A stronger NPO increases productivity and chlorophyll concentration at ∼45°N. In the anthropogenic climate change scenario, simulated sea surface temperature is 4 °C higher with respect to contemporary conditions, leading to reduced mixing and nutrient supply at middle-subpolar latitudes. The seasonal phytoplankton bloom is reduced and occurs one month earlier, the flow of carbon to the microbial loop is enhanced, and phytoplanktonic stoichiometry is nutrient-depleted. Primary productivity is enhanced at subpolar latitudes, due to increased ice-free regions and possibly to temperature-related photosynthesis stimulation. This study highlights that natural climate variability may act alternatively to strengthen or to weaken the human-induced impacts, and that in the next decades it will be difficult to distinguish between internal and external climate forcing on North Pacific plankton groups.
    Description: Published
    Description: 132-147
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: restricted
    Keywords: Plankton model; Biogeochemistry; Physiological stoichiometry; Natural climate variability; Climate change; North Pacific; Earth System Model ; 03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 03. Hydrosphere::03.01. General::03.01.07. Physical and biogeochemical interactions ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    Publication Date: 2017-04-04
    Description: Mt. Moio is the most peripheral scoria cone of Etna volcano and rises above the Peloritani Mountains sedimentary basement, 18 km north of the volcano summit. Geological and tephrostratigraphic studies and 40Ar/39Ar age determinations were used to characterize the eruption and constrain its occurrence to ~ 29 ka ago, during the activity of the Ellittico volcano, the volcanic edifice active before the actual one, the Mongibello volcano. The Mt. Moio eruption formed a large scoria cone and a widespread tephra fallout deposit, indicating that vigorous explosive activity produced an eruptive plume; minor effusive activity produced a small lava flow at the end of the eruption. Geochemical data indicate that the composition of erupted magma became less evolved during the eruption (mugearite → basalt–hawaiite); thus Mt. Moio deposits have been divided into Lower and Upper Sequences characterized by similar depositional facies. Based on the classification of Etna flank eruptions available in the literature, Mt. Moio can be classed as an eccentric (sensu Rittmann) and Class B eruption. Historic flank eruptions (e.g. 1669, 1763, 2001, 2002–03) formed deposits that are petrochemically and stratigraphically similar to those of Mt. Moio. The general trend of the Mt. Moio eruptive fissure corresponds to that of extensional neotectonic lineaments in the Apenninic–Maghrebian Chain, indicating that the structure of the basement played a role in controlling the ascent of the volatile-rich magma during Ellittico volcano activity.
    Description: Published
    Description: 49-60
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: restricted
    Keywords: Etna Volcano ; Tephrostratigraphy ; 40Ar/39Ar age determination ; Flank eruption ; Magma intrusion ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    Publication Date: 2021-09-03
    Description: Gas hazard was evaluated in the three most important cold gas emission zones on the flanks of the quiescent Colli Albani volcano. These zones are located above structural highs of the buried carbonate basement which represents the main regional aquifer and the main reservoir for gas rising from depth. All extensional faults affecting the limestone reservoir represent leaking pathways along which gas rises to the surface and locally accumulates in shallow permeable horizons forming pressurized pockets that may produce gas blowout when reached by wells. The gas, mainly composed by CO2 (〉90 vol.%), contains appreciable quantities of H2S (0.35-6 vol.%), and both represent a potentially high local hazard. Both gases are denser than air and accumulate near ground where they may reach hazardous concentrations, and actually lethal accidents frequently occur to animals watering at local ponds. In order to evaluate the rate of degassing and the related hazard, CO2 and H2S diffuse soil flux surveys have been repeatedly carried out by accumulation chamber. The viscous gas flux of some important discrete emissions has been also evaluated and the CO2 and H2S air concentration measured by portable devises and by Tunable Diode Laser profiles. The minimum potential lethal concentration of the two gases (250 ppm for H2S and 8 vol.% for CO2) is 320 times higher for CO2, whereas the CO2/H2S concentration ratio in the emitted natural gas is significantly lower (15-159). This explains why H2S reaches hazardous, even lethal, concentrations more frequently than CO2. A relevant hazard exists for both gases in the depressed zones (channels, excavations) particularly in the non-windy early hours of the day.
    Description: Published
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: partially_open
    Keywords: gas hazard ; hydrogen sulfide ; carbon dioxide ; Colli Albani volcano ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 37
    Publication Date: 2021-12-06
    Description: Major, minor and trace element analysis of volcanic glass in proximal and distal (〈 2 mm) tephra deposits underpins tephrochronology. This approach has been tested in the Aeolian Islands and the Tyrrhenian Sea using juvenile clasts in pyroclastic fall and flow deposits. Geochemical data are used to link marine tephras in the Marsili Basin (core TIR2000-C01) to explosive eruptions of (1) Lipari (Monte Pilato; 776 cal AD); (2) Vulcano; and (3) Campi Flegrei (Soccavo 1; 11,915–12,721 cal years BP). Whether a polymictic coarse grained volcaniclastic turbidite in the Marsili Basin originated from collapse on Salina remains unresolved because multi-elemental analysis raises doubt about the published correlation to the Pollara region. It is evident that correlation of proximal continental and distal marine tephras, at a high level of confidence, requires a full complement of major, minor and trace element data. In conjunction with considerations of the mineralogy and morphology of juvenile deposits these data help define petrological lineages such that precise provenance can be established. Whilst a precise proximal–distal match must be based on identical major, minor and trace element concentrations it is clear that resurgent activity from a single volcano can produce magmas with identical compositions. In such cases stratigraphic relationships must complement any geochemical study. Occasionally proximal stratigraphies may be unrepresentative of the complete eruptive history because of a lack of exposure due to burial by more recent effusive and explosive activity, or sector collapse which can remove vital stratigraphy particularly on volcanic islands.
    Description: Published
    Description: 74-94
    Description: JCR Journal
    Description: restricted
    Keywords: Marsili Basin ; Glass chemistry ; Tephra ; Trace element ; Aeolian Islands ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
    Publication Date: 2021-12-06
    Description: A rock-magnetic investigation was carried out on the nonwelded ash deposits of the Brown Tuffs (Aeolian Islands, southern Tyrrhenian Sea) to improve the stratigraphic correlation between the deposits cropping out on Lipari and Vulcano islands and locate their source area. The study was supplemented by petrographical and geochemical analyses on selected strata, with the intent to compare the Brown Tuffs to other rocks emplaced at Vulcano in the same time span. More than 30 levels were sampled in the intermediate (56± 4 kaNIBTN21–22 ka) and upper (21–22 kaNUBT) parts of the Brown Tuffs sequences on the two islands. Their characteristic remanent magnetization (ChRM) directions were derived from stepwise thermal demagnetization, and the magnetic fabric from measurements of the anisotropy of magnetic susceptibility. The levels with indistinguishable ChRM directions were regarded as coeval and to form an individual stratigraphic unit. The units were referred to the Brown Tuffs sequence of Lucchi et al. (2008) on the grounds of their emplacement age, provided by comparison of their mean paleomagnetic direction with the paleosecular variation curves of the southern Tyrrhenian region, as well as the field constraints. The closer correlation between the sequences of Lipari and Vulcano contributes to a better understanding of the volcanic activity that produced the Brown Tuffs, and shows that most of the IBT and the oldest UBT levels were emplaced in a short time span, between ≈24 and 20–17 ka. The magnetic fabric is typically well developed, but at most sites the magnetic foliation is very close to horizontal and no imbrication is defined. The source area of the Brown Tuffs parent pyroclastic flows, as constrained from the intersection of the magnetic lineations, falls in the northeastern part of La Fossa Caldera structure. Although limited to major elements, compositional data provide further indication about the parent plumbing system and its behaviour. Magma batch(es) involved in the IBT eruptions have homogeneous features and underwent frequent refilling and tapping processes. Conversely, those involved in the early UBT eruptions are compositionally more variable. This suggests more complex evolution and plumbing system activity: the UBT eruptions represent either residual mafic magmas from the previous eruptions or the arrival of new, fresh shoshonitic magma in the system.
    Description: Published
    Description: 23-38
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Brown Tuffs ; Magnetic fabric ; pyroclastic rocks ; Aeolian Islands ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 39
    Publication Date: 2023-01-27
    Description: Our ability to monitor volcanoes (using seismic signals, ground deformation, gas fluxes, or other ground and satellite based observations) as well as our understanding of melt reservoirs that feed eruptions have evolved tremendously in recent years. The complex plumbing systems that are thought to feed eruptions are, however, difficult to relate to the monitoring signals. Here we show that the record preserved in compositional zoning of erupted minerals may be used to reconstruct sections of the plumbing system. Kinetic modeling of such zoning can yield information on the residence time of magma in different segments of the plumbing systems. This allows a more nuanced evaluation of the link between observed monitoring signals or eruption styles and the magmatic processes and movement of batches of melts at depth. The approach is illustrated through a study of the compositional zoning recorded in olivine crystals from the 1991–1993 SE-flank eruption products of Mt. Etna (Sicily). The zoning patterns in crystals reveal that the plumbing system of the volcano consisted of at least three different magmatic environments between which magma was transported and mixed in the year or two preceding the start of eruption. Quantification of this history indicates that two main pathways of melt migration and three timescales dominated the dynamics of the system. Combination of this information with the timing of observation of various monitoring signals allows a reconstruction of the dynamic evolution of this section of the plumbing system during the early stages of the 1991–1993 eruption. It is seen, for example, how the migration of melt through the same sections of the plumbing system can cause pre-eruptive triggering, enhance Strombolian activity, and through the ensuing eruption cleanse and flush the plumbing system. Different kinds of mixing occur simultaneously at different sections of the plumbing system on different timescales (a few days up to two years).
    Description: Published
    Description: 11-22
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; plumbing system ; olivine ; zoning ; timescales ; monitoring ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 40
    Publication Date: 2021-04-07
    Description: This paper compares stable isotope (δ18O and δ13C) records of early–middle Holocene land snail shells from the archaeological deposits of Grotta di Latronico 3 (LTR3; southern Italy) with modern shell isotopic data. No substantial interspecific variability was observed in shell δ18O (δ18Os) of modern specimens (Pomatias elegans, Cornu aspersum, Eobania vermiculata, Helix ligata and Marmorana fuscolabiata). In contrast, interspecific shell δ13C (δ13Cs) variability was significant, probably due to different feeding behaviour among species. The δ18Os values of living land snails suggest that species hibernate for a long period during colder months, so that the signal of 18O-depleted winter rainfall in their δ18Os is lost. This suggests that δ18Os and δ13Cs values of Pomatias elegans from this archaeological succession provide valuable clues for seasonal (spring–autumn) climatic conditions during the early–middle Holocene. The δ18Os values of fossil specimens are significantly lower than in modern shells and in agreement with other palaeoclimatic records, suggesting a substantial increase of precipitation and/or persistent changes in air mass source trajectories over this region between ca. 8.8 cal ka BP and 6.2–6.7 ka ago. The δ13Cs trend suggests a transition from a slightly 13C-enriched to a 13C-depleted diet between early and middle Holocene compared to present conditions. We postulate that this δ13Cs trend might reflect changes in the C3 vegetation community, potentially combined with other environmental factors such as regional moisture increase and the progressive decrease of atmospheric CO2 concentration. Copyright © 2010 John Wiley & Sons, Ltd.
    Description: Published
    Description: 1347-1359
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: central Mediterranean ; archaeological succession ; land snail shells ; stable isotopes ; palaeoclimate ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
    Publication Date: 2020-11-26
    Description: The volcano–hydrothermal system of El Chichón volcano, Chiapas, Mexico, is characterized by numerous thermal manifestations including an acid lake, steam vents and boiling springs in the crater and acid and neutral hot springs and steaming ground on the flanks. Previous research on major element chemistry reveals that thermal waters of El Chichón can be divided in two groups: (1) neutral waters discharging in the crater and southern slopes of the volcano with chloride content ranging from 1500 to 2200 mg/l and (2) acid-toneutral waters with Cl up to 12,000 mg/l discharging at the western slopes. Our work supports the concept that each group of waters is derived from a separate aquifer (Aq. 1 and Aq. 2). In this study we apply Sr isotopes, Ca/Sr ratios and REE abundances along with the major and trace element water chemistry in order to discriminate and characterize these two aquifers. Waters derived from Aq. 1 are characterized by 87Sr/86Sr ratios ranging from 0.70407 to 0.70419, while Sr concentrations range from 0.1 to 4 mg/l and Ca/Sr weight ratios from 90 to 180, close to average values for the erupted rocks. Waters derived from Aq. 2 have 87Sr/86Sr between 0.70531 and 0.70542, high Sr concentrations up to 80 mg/l, and Ca/Sr ratio of 17–28. Aquifer 1 is most probably shallow, composed of volcanic rocks and situated beneath the crater, within the volcano edifice. Aquifer 2 may be situated at greater depth in sedimentary rocks and by some way connected to the regional oil-gas field brines. The relative water output (l/s) from both aquifers can be estimated as Aq. 1/Aq. 2– 30. Both aquifers are not distinguishable by their REE patterns. The total concentration of REE, however, strongly depends on the acidity. All neutral waters including high-salinity waters from Aq. 2 have very low total REE concentrations (b0.6 μg/l) and are characterized by a depletion in LREE relative to El Chichón volcanic rock, while acid waters from the crater lake (Aq. 1) and acid AS springs (Aq. 2) have parallel profile with total REE concentration from 9 to 98 μg/l. The highest REE concentration (207 μg/l) is observed in slightly acid shallow cold Ca-SO4 ground waters draining fresh and old pyroclastic deposits rich in magmatic anhydrite. It is suggested that the main mechanism controlling the concentration of REE in waters of El Chichón is the acidity. As low pH results from the shallow oxidation of H2S contained in hydrothermal vapors, REE distribution in thermal waters reflects the dissolution of volcanic rocks close to the surface or lake sediments as is the case for the crater lake.
    Description: -
    Description: Published
    Description: 55-66
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: hydrogeochemistry ; geothermal systems ; Sr isotopes ; REE ; El Chichón Volcano ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 42
    Publication Date: 2020-10-13
    Description: Deformation sources in volcanic areas are generally modeled in terms of pressurized tri-axial ellipsoids or pressurized cracks with simple geometrical shapes, embedded in a homogeneous half-space. However, the assumption of a particular source mechanism and the neglect of medium heterogeneities bias significantly the estimate of source parameters. A more general approach describes the deformation source in terms of a suitable moment tensor. Ratios between moment tensor eigenvalues are shown to provide a strong diagnostic tool for the physical interpretation of the deformation source and medium heterogeneities may be accounted for through 3D finite element computations. Leveling and EDM data, collected during the 1982–84 unrest episode at Campi Flegrei (Italy), are employed to retrieve the complete moment tensor according to a Bayesian inversion procedure, considering the heterogeneous elastic structure of the volcanic area. Best fitting moment tensors are found to be incompatible with any pressurized ellipsoid or crack. Taking into account the deflation of a deeper magma reservoir, which accompanies the inflation of a shallower source, data fit improves considerably but the retrieved moment tensor of the shallow source is found to be incompatible with pressurized ellipsoids, still. Looking for alternative physical models of the dislocation source, we find that the best fit moment tensor can be best interpreted in terms of a mixed mode (shear and tensile) dislocation at 5.5 km depth, striking EW and dipping by ~25°–30° to the North. Gravity changes are found to be compatible with the intrusion of ~60–70·10^6 m^3 of volatile rich magma with density ~2400 kg/m^3.
    Description: Published
    Description: 175-185
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: volcanic source ; unrest ; finite element ; inverse theory ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
    Publication Date: 2021-05-11
    Description: The CO2 laser-based lidar ATLAS has been used to study the Stromboli volcano plume. ATLAS measured water vapor concentration in cross-sections of the plume and wind speed at the crater. Water vapor concentration and wind speed were retrieved by differential absorption lidar and correlation technique, respectively. Lidar returns were obtained up to a range of 3 km. The spatial resolution was 15 mand the temporal resolution was 20 s. By combining these measurements, the water vapor flux in the Stromboli volcano plume was found. To our knowledge, it is the first time that lidar retrieves water vapor concentrations in a volcanic plume.
    Description: Published
    Description: 1295–1298
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: reserved
    Keywords: Lidar ; Volcanic plume ; DIAL ; Water vapor ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 44
    Publication Date: 2017-04-04
    Description: Explosive activity at Stromboli is explained in terms of dynamics of large gas bubbles that ascend in the magma conduit and burst at the free surface generating acoustic pressure that propagates as infrasonic signals in the atmosphere. The rate and the amplitude of the infrasonic activity is directly linked to the rate and the overpressure of the bursting gas bubbles and thus reflects the rate at which magma column degasses under non-equilibrium pressure conditions. We investigate the link between explosive degassing and magma vesiculation by comparing the rate of infrasonic activity with the bubble size distributions (BSDs) of scoria clasts collected during several days of explosive activity at Stromboli. BSDs of scoria show a characteristic power law distribution, which reflect a gas bubble concentration mainly controlled by a combined process of bubble nucleation and coalescence. The cumulative distribution of the infrasonic pressure follows two power laws, indicating a clear separation between the frequent, but weak, bursting of small gas bubbles (puffing) and the more energetic explosions of large gas slugs. The exponents of power laws derived for puffing and explosive infrasonic activity show strongly correlated (0.96) changes with time indicating that when the puffing rate is high, the number of energetic explosions is also elevated. This correlation suggests that both puffing and explosive activity are driven by the same magma degassing dynamics. In addition, changes of both infrasonic power law exponents are very well correlated (0.92 with puffing and 0.87 with explosions) with variations of the BSD exponents of the scoria clasts, providing evidence of the strong interplay between scoria vesiculation and magma explosivity. Our analysis indicates that variable magma vesiculation regimes recorded in the scoria correlate with the event number and energy of the explosive activity. We propose that monitoring infrasound on active volcanoes may be an alternative way to look at the vesiculation process in open conduit systems.
    Description: Published
    Description: 274-280
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Strombolian activity ; magma vesiculation ; infrasound ; conduit dynamics ; explosive volcanism ; bubble size distribution ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 45
    Publication Date: 2017-04-04
    Description: Society’s needs for a network of in situ ocean observing systems cross many areas of earth and marine science. Here we review the science themes that benefit from data supplied from ocean observatories. Understanding from existing studies is fragmented to the extent that it lacks the coherent long-term monitoring needed to address questions at the scales essential to understand climate change and improve geo-hazard early warning. Data sets from the deep sea are particularly rare with long-term data available from only a few locations worldwide. These science areas have impacts on societal health and well-being and our awareness of ocean function in a shifting climate. Substantial efforts are underway to realise a network of open-ocean observatories around European Seas that will operate over multiple decades. Some systems are already collecting high-resolution data from surface, water column, seafloor, and sub-seafloor sensors linked to shore by satellite or cable connection in real or near-real time, along with samples and other data collected in a delayed mode. We expect that such observatories will contribute to answering major ocean science questions including: How can monitoring of factors such as seismic activity, pore fluid chemistry and pressure, and gas hydrate stability improve seismic, slope failure, and tsunami warning? What aspects of physical oceanography, biogeochemical cycling, and ecosystems will be most sensitive to climatic and anthropogenic change? What are natural versus anthropogenic changes? Most fundamentally, how are marine processes that occur at differing scales related? The development of ocean observatories provides a substantial opportunity for ocean science to evolve in Europe. Here we also describe some basic attributes of network design. Observatory networks provide the means to coordinate and integrate the collection of standardised data capable of bridging measurement scales across a dispersed area in European Seas adding needed certainty to estimates of future oceanic conditions. Observatory data can be analysed along with other data such as those from satellites, drifting floats, autonomous underwater vehicles, model analysis, and the known distribution and abundances of marine fauna in order to address some of the questions posed above. Standardised methods for information management are also becoming established to ensure better accessibility and traceability of these data sets and ultimately to increase their use for societal benefit. The connection of ocean observatory effort into larger frameworks including the Global Earth Observation System of Systems (GEOSS) and the Global Monitoring of Environment and Security (GMES) is integral to its success. It is in a greater integrated framework that the full potential of the component systems will be realised.
    Description: Published
    Description: 1-33
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: Seafloor and water columnobservatories ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 03. Hydrosphere::03.01. General::03.01.07. Physical and biogeochemical interactions ; 03. Hydrosphere::03.01. General::03.01.08. Instruments and techniques ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 03. Hydrosphere::03.03. Physical::03.03.02. General circulation ; 03. Hydrosphere::03.03. Physical::03.03.03. Interannual-to-decadal ocean variability ; 03. Hydrosphere::03.03. Physical::03.03.05. Instruments and techniques ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.05. Geomagnetism::04.05.05. Main geomagnetic field ; 04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.03. Heat generation and transport ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data ; 05. General::05.08. Risk::05.08.01. Environmental risk ; 05. General::05.08. Risk::05.08.02. Hydrogeological risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 46
    Publication Date: 2020-02-24
    Description: Absolute chronologies of active volcanoes and consequently timescales for eruptive behaviour and magma production form a quantitative basis for understanding the risk of volcanoes. Surprisingly, the youngest records in the geological timescale often prove to be the most elusive when it comes to isotopic dating. Absolute Holocene volcanic records almost exclusively rely on 14C ages measured on fossil wood or other forms of biogenic carbon. However, on volcanic flanks, fossil carbon is often not preserved, and of uncertain origin when present in paleosols. Also, low 14C-volcanic CO2 may have mixed with atmospheric and soil 14C-CO2, potentially causing biased ages. Even when reliable data are available, it is important to have independent corroboration of inferred chronologies as can be obtained in principle using the 40K/40Ar decay system. Here we present results of a 40Ar/39Ar dating study of basaltic groundmass in the products from the Pleistocene e Holocene boundary until the beginning of the historic era for the north-northeastern flank of Stromboli, Aeolian Islands, Italy, identifying a short phase of intensified flank effusive activity 7500 500 a ago, and a maximum age of 4000 900 a for the last flank collapse event that might have caused the formation of the Sciara del Fuoco depression. We expect that under optimum conditions 40Ar/39Ar dating of basaltic groundmass samples can be used more widely for dating Holocene volcanic events.
    Description: The mapping of Stromboli was supported by a grant to S. Calvari (Project V2/01, 2005-2007, funded by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and by the Italian Civil Protection). The sample preparation was carried out by Roel van Elsas of the Institute of Earth Sciences, VU. The new instrumentation in the argon laboratory Institute of Earth Sciences, VU (instrument grant for the CO2 laser, AGES extraction line) was supported by grants from the ISES, VU-Energy conservation fund and the Institute of Earth Sciences). This work was partly supported by INGV through a research grant financed by MIUR-FIRB to G.N.
    Description: Published
    Description: 223-232
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: geochronology ; Stromboli geology ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 47
    Publication Date: 2017-04-04
    Description: A stratigraphic and chronological study of the upper level of Renella Cave (Apuan Alps, Central Italy) reveals that two episodes of flowstone accumulation bracket a thick clastic layer deposited between ca 8.2 and 7.1 ka. This layer, which represents a period of enhanced cave flooding, is substantially in phase with an interval of depleted oxygen isotope values previously recorded in a stalagmite from nearby Corchia Cave, interpreted to have resulted from an increase in local precipitation. These data confirm that during this period of time the region experienced relatively wetter conditions, including an increase in high-magnitude events capable of invading the higher passages of Renella Cave. The timing of the clastic phase occurred when the Eastern Mediterranean experienced deposition of sapropel layer S1, which is thought to reflect the stagnation of sea water produced largely by enhanced flood activity along the Nile in response to increased monsoon intensity in northern equatorial Africa. Recent estimates suggest that S1 may have lasted from ca 10.8 to ca 6.1 ka cal BP. Combined evidence from Renella and Corchia Cave indicates that the period corresponding to the wettest phase in the Apuan Alps was much shorter than this, and suggests that there is no straightforward connection between increased advection of water vapour from the Atlantic between 8.2 and 7.1 ka, as recorded in the Corchia and Renella records, and monsoon-driven enhancement of Nile discharge and S1 deposition in the eastern Mediterranean.
    Description: In press
    Description: (9)
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: Speleothems ; Floods ; Paleoclimate ; Holocene ; Renella cave ; Italy ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 48
    Publication Date: 2017-04-04
    Description: Results of observations of the Mt. Vesuvius caldera, carried out by means of terrestrial laser scanning (TLS) in May 2005, October 2006 and June 2009, are reported here. In each survey the whole crater was acquired with 17/20 scans from 6 different viewpoints and the corresponding digital surface models were generated and registered into the UTM-WGS84 reference frame. In this way, a comparison between the multitemporal models leads to an evaluation of the occurred changes. The deformation maps, i.e. the contouring plots of the differences between the models along the direction of maximum variations, showed a progressive mass loss due to rock-falls from the NE vertical crater wall whose area was about 5000m2. The TLS data also showed the accumulation at the bottom. The volume loss which occurred from 2005 to 2009, was computed by subtraction of volumes defined with respect to reference planes parallel to the caldera walls and was estimated to be 20 300 m3. The volume uncertainties due to registration errors, subsampling noise effects, and effects due to choice of the reference plane, were also estimated. Some results were also interpreted on the basis of micro-seismic and meteorological data in order to plan a monitoring technique where seismic signals related to rock-fall and/or signals of intense rainfalls are used as alarms for fast TLS surveys able to characterize the corresponding changes of the caldera walls. The proposed methodology, in particular the simple but effective approach used in the estimation of volume uncertainties, can be applied to each rock slope instability phenomenon, regardless of the particular environment.
    Description: In press
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Terrestrial laser scanning ; 3D model ; Vesuvius ; Landslide ; volume ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 49
    Publication Date: 2017-04-04
    Description: To develop a model of both the structure and evolution of the Campi Flegrei caldera (CFc) magmatic feeding system, geochronological, geochemical and Sr, Nd, Pb and B isotopic data of representative volcanic products of the past 15 ka have been combined with geophysical and melt inclusion literature data, structural setting and dynamics of the resurgent caldera. According to previous petrological data, the CFc magmatic feeding system consists of a deep reservoir, in which mantle-derived K-basaltic parental magmas differentiate to shoshonite, latite and trachyte, through combined crustal contamination and fractional crystallization processes, and shallowreservoirswhere the evolvedmagmas further differentiate andmingle/mix before eruptions. The Sr,Nd, Pb, and B isotope data allowrecognition of three distinctmagmatic components.One component is believedto be residualmagmafromtheNeapolitanYellowTuff (NYT) caldera forming eruption. The NYT component (87Sr/86Sr of 0.70750–53, 143Nd/144Nd ratio of ca. 0.51246, 206Pb/204Pb of ca. 19.04 and δ11B of ca. –7.9‰), has been the most prevalent component over the past 15 ka being mixed, in most cases, with the other two components. One of these other components is best recognized in the Minopoli 2 magma, first erupted 10 ka ago. Minopoli 2 magma is shoshonitic in composition and is the most enriched in radiogenic Sr (87Sr/86Sr of ca. 0.70860) and unradiogenic Nd and Pb (143Nd/144Nd ratio of ca. 0.51236, 206Pb/204Pb of ca. 18.90), and is characterised by δ11B value of ca. –7.32‰. The third component is trachytic in composition and has higher 206Pb/204Pb (ca. 19.08), lower 87Sr/86Sr (ca. 0.70726) and δ11B (−9.8‰) and higher 143Nd/144Nd (ca. 0.51250), with respect to the NYT component. This third component is best recognized in the Astroni 6 magma and did not appear until ca. 4 ka. The identified isotopically distinct magmatic components were erupted in different sectors of the CFc. During both I (b14.9–9.5 ka) and II (8.6–8.2 ka) epochs of volcanic activity,magmas similar to the NYT component, and those resulting from mixing between Minopoli 2 and NYT components were erupted from vents located mostly on the marginal faults of the NYT caldera. During the III epoch (4.8–3.8 ka) magmas either similar to NYT, or resulting from mixing between Astroni 6 and NYT components were erupted from vents located along faults bordering the La Starza resurgent block and, subordinately, the NYT caldera. Moreover, magmas resulting from mixing betweenMinopoli 2 and NYT components were erupted fromvents located along NE–SW regional faults activated during caldera resurgence. The inferred present structure of the feeding system is characterised by a deep reservoir, whose top is at about 8 kmdepth, that hosts shoshonitic–trachyticmagmas. Remnants of the NYT magma reside at shallower depth in different sectors of the crust underlying CFc, and were sometimes intercepted by volatile-rich magmas of deep provenance during the three epochs of CFc volcanic activity.
    Description: Published
    Description: 227-241
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Campi Flegrei caldera ; Magmatic system ; Caldera structure ; Geochemistry ; Isotopes ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 50
    Publication Date: 2020-02-24
    Description: Questo lavoro ha analizzato i risultati del monitoraggio termico delle eruzioni di Stromboli del 2002-2003 e 2007, ed ha mostrato come prima di ogni parossisma il volume di lava eruttato nel corso dell’attività effusiva sia stato confrontabile. Questa osservazione ha fatto ipotizzare l’esistenza di una decompressione critica nel sistema di alimentazione superficiale del vulcano, raggiungibile anche lentamente, che innesca la veloce risalita del magma ricco in gas, responsabile dei parossismi. Durante l’attività effusiva, a questa decompressione critica è associabile una soglia di volume di magma emesso, che diventa la misura discriminante per valutare la fase critica del vulcano e predire il parossisma.
    Description: The 2007 effusive eruption of Stromboli followed a similar pattern to the previous 2002-3 episode. In both cases, magma ascent led to breaching of the uppermost part of the conduit forming an eruptive fissure that discharged lava down the Sciara del Fuoco depression. Both eruptions also displayed a ‟paroxysmal„ explosive event during lava flow output. From daily effusion rate measurements retrieved from helicopter- and satellite-based infrared imaging, we deduce that the cumulative volume of lava erupted before each of the two paroxysms was similar. Based on this finding, we propose a conceptual model to explain why both paroxysms occurred after this „threshold‟ cumulative volume of magma was erupted. The gradual decompression of the deep plumbing system induced by magma withdrawal and eruption, drew deeper volatile-rich magma into the conduit, leading to the paroxysms. The proposed model might provide a basis for forecasting paroxysmal explosions during future effusive eruptions of Stromboli.
    Description: This paper was partially supported by a research project (Project INGV-DPC Paroxysm V2/03, 2007–2009) funded by the Istituto Nazionale di Geofisica e Vulcanologia and by the Italian Civil Protection. E.R. thanks Rafal Dunin-Borkowski, director of Cen/DTU (Denmark), for logistic support.
    Description: Published
    Description: 317-323
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: restricted
    Keywords: Stromboli volcano ; effusive eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 51
    Publication Date: 2020-02-24
    Description: In this paper we present a model for the growth of a maar-diatreme complex in a shallow marine environment. The Miocene-age Costa Giardini diatreme near Sortino, in the region of the Iblei Mountains of southern Sicily, has an outer tuff ring formed by the accumulation of debris flows and surge deposits during hydromagmatic eruptions. Vesicular lava clasts, accretionary lapilli and bombs in the older ejecta indicate that initial eruptions were of gas-rich magma. Abundant xenoliths in the upper, late-deposited beds of the ring suggest rapid magma ascent, and deepening of the eruptive vent is shown by the change in slope of the country rock. The interior of the diatreme contains nonbedded breccia composed of both volcanic and country rock clasts of variable size and amount. The occurrence of bedded hyaloclastite breccia in an isolated outcrop in the middle-lower part of the diatreme suggests subaqueous effusion at a low rate following the end of explosive activity. Intrusions of nonvesicular magma, forming plugs and dikes, occur on the western side of the diatreme, and at the margins, close to the contact between breccia deposits and country rock; they indicate involvement of volatile-poor magma, possibly during late stages of activity. We propose that initial hydromagmatic explosive activity occurred in a shallow marine environment and the ejecta created a rampart that isolated for a short time the inner crater from the surrounding marine environment. This allowed explosive activity to draw down the water table in the vicinity of the vent and caused deepening of the explosive center. A subsequent decrease in the effusion rate and cessation of explosive eruptions allowed the crater to refill with water, at which time the hyaloclastite was deposited. Emplacement of dikes and plugs occurred nonexplosively while the breccia sediment was mostly still soft and unconsolidated, locally forming peperites. The sheltered, low-energy lagoon filled with marine limestones mixed with volcaniclastic material eroded from the surrounding ramparts. Ultimately, lagoonal sediments accumulated in the crater until subsidence or erosion of the tuff ring caused a return to normal shallow marine conditions.
    Description: LT thanks the Faculty Research Committee of Le Moyne College for providing travel funds that made this collaboration possible.
    Description: Published
    Description: 557–576
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: restricted
    Keywords: Iblean Mountains ; explosive eruptions ; diatremes ; shallow water environment ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 52
    Publication Date: 2017-04-04
    Description: A better understanding of degassing processes at open-vent basaltic volcanoes requires collection of new datasets of H2O–CO2–SO2 volcanic gas plume compositions, which acquisition has long been hampered by technical limitations. Here, we use the MultiGAS technique to provide the best-documented record of gas plume discharges from Stromboli volcano to date. We show that Stromboli's gases are dominated by H2O (48–98 mol%; mean, 80%), and by CO2 (2–50 mol%; mean, 17%) and SO2 (0.2–14 mol%; mean, 3%). The significant temporal variability in our dataset reflects the dynamic nature of degassing process during Strombolian activity; which we explore by interpreting our gas measurements in tandem with the melt inclusion record of pre-eruptive dissolved volatile abundances, and with the results of an equilibrium saturation model. Comparison between natural (volcanic gas and melt inclusion) and modelled compositions is used to propose a degassing mechanism for Stromboli volcano, which suggests surface gas discharges are mixtures of CO2-rich gas bubbles supplied from the deep (〉 4 km) plumbing system, and gases released from degassing of dissolved volatiles in the magma filling the upper conduits. The proposed mixing mechanism offers a viable and general model to account for composition of gas discharges at all volcanoes for which petrologic evidence of CO2 fluxing exists. A combined volcanic gas-melt inclusion-modelling approach, as used in this paper, provides key constraints on degassing processes, and should thus be pursued further.
    Description: Published
    Description: 195-204
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: volcanic degassing ; Stromboli ; volcanic gases ; CO2 fluxing ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 53
    Publication Date: 2017-04-04
    Description: Pantelleria Island, located in the Sicily Channel Rift Zone (Italy), is the type locality for the peralkaline rhyolitic rocks called pantellerites. In the last 50 ka, after the large Green Tuff caldera-forming eruption, volcanic activity at Pantelleria has consisted of effusive and explosive eruptions mostly vented inside and along the rim of the caldera and producing silicic lava flows, lava domes and poorly dispersed pantelleritic pumice fall deposits. Basaltic cinder cones and lava flows are only present outside the caldera in the NW sector of the island. The most recent basaltic (Cuddie Rosse, 20 ka) and pantelleritic (Cuddia Randazzo and Cuddia del Gallo, 6 ka) pyroclastic products were sampled to investigate magmatic volatile contents through the study of melt inclusions. The melt inclusions in pyroxene and olivine phenocrysts of Cuddie Rosse scoriae have an alkali basalt composition. The dissolved volatiles comprise 0.9–1.6 wt.% H2O, several hundred ppm of CO2, 1600–2000 ppm of sulphur and 500–900 ppm of chlorine. The water–carbon dioxide couple gives a confining pressure 2 kbar prior to the eruption. This result indicates that episodes of magma ponding and crystallization occurred in the upper crust prior to eruption. The melt inclusions in feldspar, fayalite and aenigmatite phenocrysts of Cuddia del Gallo and Cuddia Randazzo pumice have a pantelleritic composition (Agpaitic Indices 1.3–2.1), up to 4.4 wt.% H2O, 8700 ppm Cl, 6000 ppm F, and CO2 below the detection limit. Sulphur averaging 420 ppm has been measured in Cuddia Randazzo melt inclusions. These data indicate relatively high volatile contents for these low-energy Strombolian-type eruptions. Melt inclusions in Cuddia del Gallo pumice show the most evolved composition (Agpaitic Indices 2–2.1) and the highest volatile content, in agreement with fluid saturation conditions in the magma chamber prior to the eruption. This implies a confining pressure of 1 kbar for the top of the pantelleritic reservoir. The composition of melt inclusions and mineralogical assemblage of Cuddia Randazzo pumice indicate that it has a lower evolutionary degree (Agpaitic Indices 1.3–1.8) and lower pre-eruptive Cl and H2O contents than Cuddia del Gallo pumice. An increase in pressure due to the exsolution of volatiles in the upper part of the pantelleritic reservoir may have triggered the Cuddia del Gallo explosive eruption. Evidence of widespread pre-eruptive mingling between trachytes and pantellerites suggests that the intrusion of trachytic magma into the pantelleritic reservoir likely played a major role in destabilizing the magma system just prior to the Cuddia Randazzo event.
    Description: Published
    Description: 191-201
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Pantelleria ; peralkaline ; volatiles ; melt inclusions ; eruptive style ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 54
    Publication Date: 2017-04-04
    Description: We report simultaneous laboratory measurements of seismic velocities and fluid permeability on lava flow basalt from Etna (Italy). Results were obtained for dry and saturated samples deformed under triaxial compression. During each test, the effective pressure was first increased up to 190 MPa to investigate the effect of pre-existing crack closure on seismic properties. Then, the effective pressure was unloaded down to 20 MPa, a pressure which mirrors the stress field acting under a lava pile of approximately 1.5–2 km thick, and deviatoric stress was increased until failure of the specimens. Using an effective medium model, the measured elastic wave velocities were inverted in terms of two crack densities: ρi the crack density of the pre-existing thermal cracks and ρv the crack density of the stress-induced cracks. In addition a link was established between elastic properties (elastic wave velocities Vp and Vs) and permeability using a statistical permeability model. Our results show that the velocities increase with increasing hydrostatic pressure up to 190 MPa, due to the closure of the pre-existing thermal cracks. This is interpreted by a decrease of the crack density ρi from ~1 to 0.2. The effect of pre-existing cracks closure is also highlighted by the permeability evolution which decreases of more than two orders of magnitude. Under deviatoric loading, the velocities signature is interpreted, in the first stage of the loading, by the closure of the pre-existing thermal cracks. However, with increasing deviatoric loading newly-formed vertical cracks nucleate and propagate. This is clearly seen from the velocity signature and its interpretation in term of crack density, the location of the acoustic emission sources, and from microstructural observations. This competition between pre-existing cracks closure and propagation of vertical cracks is also seen from the permeability evolution, and our study shows that mechanically-induced cracks has lesser influence on permeability change than pre-existing thermal cracks.
    Description: In press
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: open
    Keywords: Elastic wave velocity, Permeability, Acoustic emission, Fracture, Basalt ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 55
    Publication Date: 2017-04-04
    Description: We report a laboratory and microstructural study of a suite of deformation experiments in which basalt from Mount Etna volcano is deformed and fractured at an effective confining pressure representative of conditions under a volcanic edifice (40 MPa). Particular attention was paid to the formation of a fracture and damage zone with which to stimulate coupled hydro-mechanical interactions that create the various types of seismicity recorded on volcanic edifices, and which usually precede eruption. Location of AE events through time shows the formation of a fault plane during which waveforms exhibit the typical high frequency characteristics of volcano-tectonic (VT) earthquakes. We found that these VT earthquakes were particularly pronounced when generated using dry samples, compared to samples saturated with a pore fluid (water). VT events generated during deformation of water saturated sample are characterised by a distinctive high frequency onset and a longer, low frequency coda exhibiting properties often seen in the field as hybrid events. We present evidence that hybrid events are, in fact, the common type of volcanic seismic event with either VT or low frequency (LF) events representing end members, and whose proportion depend on pore fluid being present in the rock type being deformed, as well as how close the rock is to failure. We find a notable trend of reducing instances of hybrid events leading up to the failure stage in our experiments, suggesting that during this stage, the pore fluid present in the rock moves sufficiently quickly to provide a resonance, seen as a LF coda. Our data supports recent modeling and field studies that postulate that hybrid events generated in volcanic areas are likely to be generated through the interaction of hydrothermal fluids moving through a combination of pre-existing microcrack networks and larger faults, such as those we observe in forensic (post-test) examination.
    Description: Published
    Description: 315-323
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: volcano-tectonics, acoustic emission, rock physics, seismology, hazard ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 56
    Publication Date: 2017-04-04
    Description: Magmatic processes triggering eruptions at Campi Flegrei caldera (southern Italy) and their relationships with the widespread emissions of fluids and caldera unrest episodes, are poorly constrained. The 4.1 ka B.P. Agnano–Monte Spina eruption, the reference event for a future large-size explosive eruption at Campi Flegrei, was investigated to shed light, through melt inclusion and isotope analyses, on the geochemical processes operating in the plumbing system. Chemical and isotopic data on whole rocks and glasses suggest that at least two magma batches mixed during the course of the eruption. Melt inclusion data highlight the pre-eruption storage conditions of two magmatic end-members. One end-member is like the less differentiated (shoshonitic) Campi Flegrei erupted magma, while the other could be a residual of the Neapolitan Yellow Tuff magma. Mixing between these two components was driven by a large gas phase which sustained the ascent of magmas of deep provenance. The H2O and CO2 contents in pyroxene-hosted melt inclusions yield entrapment pressures between 107 and 211 MPa, corresponding to depths between 4 and 8 km. The degassing trends reveal two extreme patterns. One pattern, already documented in the literature, is the volatile signature of poorly differentiated magmas ascending from more than 8 km depth, while the other is related to a gas-dominated magma, flushed by a CO2-rich gas phase partly released from the deep reservoir. This study provides a conceptual frame for unrest phases at Campi Flegrei, such as the 1982–84 event. Uplift phases can be related to closed-system ascent of magmas and fluids from more than 8 km depth, and their emplacement at shallow levels. This leads the shallow system to store, and then progressively release, the accumulated gas. In this view, both unrest episodes and eruptions could be strongly influenced by both the achievement of a critical upper limit of gas storage in the shallow magmatic reservoir and the stress and fracturing state of the roof rocks. The present results help to constrain the preeruptive conditions expected at Campi Flegrei caldera in case of a future large-size eruptive event.
    Description: Published
    Description: 135–147
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Sr and Nd isotopes ; Melt inclusions ; Gas flushing ; Magma mixing ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 57
    Publication Date: 2017-04-04
    Description: We studied the shape of the most regular-shaped stratovolcanoes of the world to mathematically define the form of the ideal stratovolcano. Based on the Shuttle Radar Topographic Mission data we selected 19 of the most circular and symmetrical volcanoes, which incidentally all belong to subduction-related arcs surrounding the Pacific. The selection of volcanoes benefitted from the introduction of a new definition of circularity which is more robust than previous definitions, being independent of the erosional dissection of the cone. Our study on the shape of stratovolcanoes was based on the analysis of the radial elevation profiles of each volcano. The lower half section of the volcanoes is always well fitted by a logarithmic curve, while the upper half section is not, and falls into two groups: it is fitted either by a line (“C-type”, conical upper part) or by a parabolic arc (“P-type”, parabolic/concave upper part). A quantitative discrimination between these groups is obtained by fitting their upper slope with a linear function: C-type volcanoes show small, whereas P-type volcanoes show significant negative angular coefficient. The proposed threshold between the two groups is − 50 × 10− 4°/m. Chemical composition of eruptive products indicates higher SiO2 and/or higher H2O content for C-type volcanoes, which could imply a higher incidence of mildly explosive (e.g. strombolian) eruptions. We propose that this higher explosivity is responsible for forming the constant uppermost slopes by the deposition of ballistic tephra and its subsequent stabilisation at a constant angle. By contrast, P-type volcanoes are characterized by a smaller SiO2 and H2O content, which can be responsible for a higher incidence of effusive events and/or a lower incidence of upper flank-forming (i.e. mild) explosive eruptions. Therefore, the concave upper flanks of these volcanoes may be shaped typically by lava flows. Based on this hypothesis, we propose that the morphometric analysis of the elevation profile of stratovolcanoes can provide insights into their dominant eruptive style.
    Description: Published
    Description: 171-181
    Description: 1.10. TTC - Telerilevamento
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: stratovolcano ; SRTM ; shape analysis ; elevation profile ; circularity ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 58
    Publication Date: 2020-12-07
    Description: We present a new method for measuring SO2 with the data from the ASTER (Advanced Spaceborne Thermal Emission and Reflectance radiometer) orbital sensor. The method consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. We present a sensitivity analysis for this method, and two case studies. The sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. Measurements with b25% relative precision are achieved, but only when the thermal contrast between the plume and the underlying surface is higher than 10 K. For the case studies we focused on Miyakejima and Etna, two volcanoes where SO2 is measured regularly by COSPEC or scanning DOAS. The SO2 fluxes computed from a series of ten images of Miyakejima over the period 2000–2002 is in agreement with the long term trend of measurement for this volcano. On Etna, we compared SO2 column amounts measured by ASTER with those acquired simultaneously by ground-based automated scanning DOAS. The column amounts compare quite well, providing a more rigorous validation of the method. The SO2 maps retrieved with ASTER can provide quantitative insights into the 2D structure of non-eruptive volcanic plumes, their dispersion and their progressive depletion in SO2.
    Description: R.C. was supported by a grant from F.R.I.A (Fond pour la Recherche Industrielle et Appliquée). GGS acknowledges a PhD grant funded by the project “Sviluppo di sistemi di monitoraggio” funded by Dipartimento di Protezione Civile della Regione Sicilia, INGV (Istituto Nazionale di Geofisica e Vulcanologia, sezione di Catania—Italy) and NOVAC (Network for Observation of Volcanic and Atmospheric Change) EU-funded FP6 project no. 18354. P-F. C. is research associate with FRS-FNRS and benefited from its financial support (F.4511.08).
    Description: Published
    Description: 42-54
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: remote sensing, SO2, ASTER, DOAS, Etna, Miyakejima ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 59
    Publication Date: 2021-01-07
    Description: The quaternary volcanic complex of Mount Amiata is located in southern Tuscany (Italy) and represents the most recent manifestation of the Tuscan Magmatic Province. The region is characterised by a large thermal anomaly and by the presence of numerous CO2-rich gas emissions and geothermal features, mainly located at the periphery of the volcanic complex. Two geothermal systems are located, at increasing depths, in the carbonate and metamorphic formations beneath the volcanic complex. The shallow volcanic aquifer is separated from the deep geothermal systems by a low permeability unit (Ligurian Unit). A measured CO2 discharge through soils of 1.8 109 mol a 1 shows that large amounts of CO2 move from the deep reservoir to the surface. A large range in d13CTDIC ( 21.07 to +3.65) characterises the waters circulating in the aquifers of the region and the mass and isotopic balance of TDIC allows distinguishing a discharge of 0.3 109 mol a 1 of deeply sourced CO2 in spring waters. The total natural CO2 discharge (2.1 109 mol a 1) is slightly less than minimum CO2 output estimated by an indirect method (2.8 109 mol a 1), but present-day release of 5.8 109 mol a 1 CO2 from deep geothermal wells may have reduced natural CO2 discharge. The heat transported by groundwater, computed considering the increase in temperature from the infiltration area to the discharge from springs, is of the same order of magnitude, or higher, than the regional conductive heat flow (〉200 mWm 2) and reaches extremely high values (up to 2700mWm 2) in the north-eastern part of the study area. Heat transfer occurs mainly by conductive heating in the volcanic aquifer and by uprising gas and vapor along fault zones and in those areas where low permeability cover is lacking. The comparison of CO2 flux, heat flow and geological setting shows that near surface geology and hydrogeological setting play a central role in determining CO2 degassing and heat transfer patterns.
    Description: Published
    Description: 860–875
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Carbon dioxide degassing ; Monte Amiata ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 60
    Publication Date: 2021-06-15
    Description: No eruption, no caldera collapse, and no landslide can take place in a volcano unless its state of stress is suitable for the associated type of rock failure. The state of stress, in turn, results in deformation, and both stress and deformation depend on the mechanical properties of the rocks that constitute the volcano. Understanding stress and deformation in volcanoes is thus of fundamental importance for understanding unrest periods and for accurate forecasting volcano failure, such as may result in large-scale lateral and vertical collapses and eruptions.
    Description: Published
    Description: 1-3
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: stress, deformation, volcano tectonics, physical propertie of volcanic rocks ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 61
    Publication Date: 2017-04-04
    Description: The 2002–03 flank eruption of Etna was characterized by two months of explosive activity that produced copious ash fallout, constituting a major source of hazard and damage over all eastern Sicily. Most of the tephra were erupted from vents at 2750 and 2800 m elevation on the S flank of the volcano, where different eruptive styles alternated. The dominant style of explosive activity consisted of discrete to pulsing magma jets mounted by wide ash plumes, which we refer to as ash-rich jets and plumes. Similarly, ash-rich explosive activity was also briefly observed during the 2001 flank eruption of Etna, but is otherwise fairly uncommon in the recent history of Etna. Here, we describe the features of the 2002–03 explosive activity and compare it with the 2001 eruption in order to characterize ash-rich jets and plumes and their transition with other eruptive styles, including Strombolian and ash explosions, mainly through chemical, componentry and morphology investigations of erupted ash. Past models explain the transition between different styles of basaltic explosive activity only in terms of flow conditions of gas and liquid. Our findings suggest that the abundant presence of a solid phase (microlites) may also control vent degassing and consequent magma fragmentation and eruptive style. In fact, in contrast with the Strombolian or Hawaiian microlite-poor, fluidal, sideromelane clasts, ash-rich jets and plumes produce crystal-rich tachylite clasts with evidence of brittle fragmentation, suggesting that high groundmass crystallinity of the very top part of the magma column may reduce bubble movement while increasing fragmentation efficiency.
    Description: Published
    Description: 110-122
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; basaltic explosive activity ; ash-rich jet and plume ; tachylite ; sideromelane ; 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
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  • 62
    Publication Date: 2017-04-04
    Description: Despite its ultra-potassic, basic geochemistry (40≤SiO2≤50 wt.%), the Alban Hills Volcanic District was characterized by a highly explosive phase of activity, the Tuscolano–Artemisio phase, which emplaced very large volumes (several tens of km3 each cycle) of pyroclastic-flow deposits, mafic in composition (SiO2≤45 wt.%) in the time span 600–350 ka. In contrast to the abundance of pyroclastic-flow deposits, very scarce basal Plinian deposits and, more in general, fallout deposits are associated to these products. While some of the pyroclastic-flow deposits have been described in previous literature, no specific work on the Tuscolano–Artemisio phase of activity has been published so far. In particular, very little is known on the products of the early stages, as well as of the final, post-caldera activity of each eruptive cycle. Here we present a comprehensive stratigraphic and geochronologic study of the Tuscolano–Artemisio phase of activity, along with new textural and petrographic data. We describe the detailed stratigraphy and petrography of five reference sections, where the most complete suites of products of the eruptive cycles, comprising the initial through the final stages, are exposed.We assess the geochronology of these sections by means of 18 new 40Ar/39Ar age determinations, integrating them with 16 previously performed, aimed to describe the eruptive behavior of the Alban Hills Volcanic District during this phase of activity, and to assess the recurrence time and the duration of the dormancies. The overall explosive activity appears to be strictly clustered in five eruptive cycles, fairly regularly spaced in time and separated by very long dormancies, in the order of several ten of kyr, during which no volumetrically appreciable eruption occurred, as the lack of deposits dated to this time-interval testify.We propose a volcanotectonic model that explains this peculiar eruptive behavior, unparalleled in the other coeval volcanic districts of the Tyrrhenian margin of Italy, as related to the local transpressive tectonic regime.
    Description: Published
    Description: 217-232
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Alban Hills 40Ar/39Ar geochronology explosive eruptions K-alkaline magmas pyroclastic-flow deposits volcanotectonics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 63
    Publication Date: 2017-04-04
    Description: The recent eruption of Stromboli in February–April 2007 offered a unique chance to test our current understanding of processes driving the transition from ordinary (persistent Strombolian) to effusive activity, and the ability of instrumental geophysical and geochemical networks to interpret and predict these events. Here, we report on the results of two years of in-situ sensing of the CO2/SO2 ratio in Stromboli's volcanic gas plume, in the attempt to put constraints on the trigger mechanisms and dynamics of the eruption. We show that large variations of the plume CO2/SO2 ratio (range, 0.9–26) preceded the onset of the eruption (since December 2007), interrupting a period of relatively-steady and low ratios (time-averaged ratio, 4.3) lasting from at least May to November 2006. By contrasting our observations with numerical simulations of volcanic degassing at Stromboli, derived by use of an equilibrium saturation model, we suggest that the pre-eruptive increase of the ratio reflected an enhanced supply of deeply-derived CO2-rich gas bubbles to the shallowplumbing system. This larger-than-normal ascent of gas bubbles was likely sourced by a 1–3 km deep gas– melt separation region (probably a magma storage zone), and caused faster convective overturning of magmas in the shallow conduit; an increase in the explosive rate and in seismic tremor, and finally the collapse of the la Sciara del Fuoco sector triggering the effusive phase. The high CO2/SO2 ratios (up to 21) observed during the effusive phase, and particularly in the days and hours before a paroxysmal explosion on March 15, 2007, indicate the persistence of the same gas source; and suggest that de-pressurization of the same 1–3 km deep magma storage zone could have been the trigger mechanism for the paroxysm itself
    Description: Published
    Description: 221-230
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; plume chemistry ; magma degassing ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 64
    Publication Date: 2017-04-04
    Description: We investigated the dynamics of explosive activity at Mt. Etna between 31 August and 15 December 2006 by combining vesicle studies in the erupted products with measurements of the gas composition at the active, summit crater. The analysed scoria clasts present large, connected vesicles with complex shapes and smaller, isolated, spherical vesicles, the content of which increases in scoriae from the most explosive events. Gas geochemistry reports CO2/SO2 and SO2/HCl ratios supporting a deep-derived gas phase for fire-fountain activity. By integrating results from scoria vesiculation and gas analysis we find that the highest energy episodes of Mt. Etna activity in 2006 were driven by a previously accumulated CO2-rich gas phase but we highlight the lesser role of syn-eruptive vesicle nucleation driven by water exsolution during ascent. We conclude that syn-eruptive vesiculation is a common process in Etnean magmas that may promote a deeper conduit magma fragmentation and increase ash formation.
    Description: Published
    Description: 265-269
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; fire-fountains ; vesicle textures ; volcanic degassing ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 65
    Publication Date: 2017-04-04
    Description: A series of computer microtomography experiments are reported which were performed by using a third-generation synchrotron radiation source on volcanic rocks from various active hazardous volcanoes in Italy and other volcanic areas in the world. The applied technique allowed the internal structure of the investigated material to be accurately imaged at the micrometer scale and three-dimensional views of the investigated samples to be produced as well as three-dimensional quantitative measurements of textural features. Thegeometryof thevesicle (gas-filledvoid) network in volcanic products of both basaltic and trachytic compositions were particularly focused on, as vesicle textures are directly linked to the dynamics of volcano degassing. This investigation provided novel insights into modes of gas exsolution, transport and loss in magmas that were not recognized in previous studies using solely conventional two- dimensional imaging techniques. The results of this study are important to understanding the behaviour of volcanoes and can be combined with other geosciences disciplines to forecast their future activity.
    Description: In press
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: high-resolution three-dimensional imaging ; X-ray computed microtomography ; volcanic eruptions ; volcanic rock textures ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 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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  • 66
    Publication Date: 2017-04-04
    Description: Mercury is outstanding among the global environmental pollutants of continuing concern. Although degassing of active volcanic areas represents an important natural source of mercury into the atmosphere, still little is known about the amount and behaviour of Hg in volcanic aquifers, especially regarding its chemical speciation. In order to assess the importance of mercury emissions from active volcanoes, thermal waters were sampled in the area surrounding La Solfatara, Pozzuoli bay. This is the most active zone of the Phlegrean Fields complex (coastal area north–west of Naples), with intense hydrothermal activity at present day. Studied groundwaters show total Hg (THg) concentrations range from 56 to 171 ng/l and are lower than the 1000 ng/l threshold value for human health protection fixed by the World Health Organization (WHO, 1993). We also carefully discriminated the different aqueous species of Hg in the collected water samples. Besides, original data on Hg determination in gaseous manifestations at La Solfatara crater are also reported. We measured volcanogenic mercury concentration and Hg/Stot ratio both in the volcanic plume and in fumarolic condensates in order to better constrain Hg reactivity once emitted into the atmosphere. Data on Hg/Stot reveal that there is no significant difference between Hg volcanic composition at the venting source (fumaroles) and in near-vent diluted volcanic plumes (1.6×10−5 and 1.9×10−5, respectively), suggesting that there is limited Hg chemical processing in volcanic fumarole plumes, at least on the timescales of a few seconds investigated here. Combining the mean fumaroles Hg/CO2 mass ratio of about 1.3×10−8 (molar ratio: 2.1×10−9) with the hydrothermal soil diffuse CO2 degassing of the area, the annual Hg flux from La Solfatara is estimated as 7 kg y−1 (0.007 t y−1). Current mercury emission from La Solfatara volcano represents a very small contribution to the estimated global volcanic budget for this element, and the estimated Hg flux is considerably lower than that estimated from open-conduit active basaltic volcanoes.
    Description: Published
    Description: 250–260
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: hydrothermal waters ; total mercury ; mercury speciation ; fumaroles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 67
    Publication Date: 2017-04-04
    Description: The Pleistocene history of climate control on sedimentation in the Southern Alps-Po Plain system, northern Italy, was reconstructed using an integrated magnetostratigraphic, palynological, and petrographical approach on a 47-m-deep core. The core mainly consists of lacustrine sediments pertaining to the Bagaggera sequence, deposited at the foothills of the Southern Alps during the late Matuyama subchron (0.99-0.78 Ma). At that time, climate worsened globally and locally it caused the progradation of an alluvial fan unit onto the nearby Po Plain, triggering lake formation by damming of a tributary valley. These new data are used in conjunction with data from the literature to highlight and track the effects of climate forcing on sedimentation during the late Matuyama subchron in different orographic and geodynamic settings of the Southern Alps-Po Plain system as part of the greater Alpine area. We found that the episodes of alluvial fan and braidplam progradation observed in the southern foreland of the Alps during the late Matuyama global cooling seem broadly synchronous with the deposition of most of the so-called Gunz and Alterer Deckenschotter deposits in the northern forelands of the Alps as well as with the first major waxing of the Alpine valley glaciers, possibly around the Marine Isotope Stage 22 (~0.87 Ma).
    Description: Regione Lombardia, IREALP
    Description: Published
    Description: 832–846
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Paleomagnetism ; Climate Change ; Early Pleistocene ; Italy ; Stratigraphy ; Petrography ; Palynology ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 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::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 68
    Publication Date: 2017-04-04
    Description: Aim of this paper is to identify variations in Very-Long-Period (VLP) source associated with eruptive style changes at Stromboli volcano (Italy) and to retrieve information about the shallow plumbing system that sustains the eruptive activity. We have considered a dataset of 74493 VLP events recorded during the period from January through August 2007, when an effusive eruption occurred (February 27–April 2).We performed a polarization analysis of the entire dataset and divided the considered period into four sub-periods on the basis of polarization characteristics. We then located the events and selected a subset of these events by applying a location quality threshold. The high quality locations demonstrate that during the effusive eruption the VLP sources first moved downward and then moved southwestward. To retrieve information about the geometry of the structures where the source processes take place, we further consider a subset of events and estimate their source mechanisms by using a moment tensor source function (MTSF) inversion technique. Inversion of the waveforms of the VLP events that occurred on February 27 allows us to obtain information about the dynamics of different source centroids distributed along different portions of the shallow magmatic conduits. The structure defined by the locations and source mechanisms shows a greater complexity compared with previous studies and their time variations give an insight into the kinematics of the eruption.
    Description: Published
    Description: 162–171
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: stromboli ; very-long-period events ; seismic source mechanism ; volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 69
    Publication Date: 2017-04-04
    Description: Permanent Scatterers Synthetic Aperture Radar Interferometry (PSInSAR) and Global Position System (GPS) are applied to investigate the most recent surface deformation of the Campi Flegrei caldera. The PSInSAR analysis, based on SAR data acquired by ERS-1/2 sensors during the 1992–2001 time interval and by the Radarsat sensor during 2003–2007, identifies displacement patterns over wide areas with high spatial resolution. GPS data acquired by the Neapolitan Volcanic Continuous GPS network provide detailed ground velocity information of specific sites. The satellite-derived data allow us to characterize the deformation pattern that affected the Campi Flegrei caldera during two recent subsidence (1992–1999) and uplift (2005– 2006) phases. PSInSAR results show the re-activation of the caldera ring-faults, intra-caldera faults, and eruptive fissures. We discuss the results in the light of the available volcanological, structural and geophysical data and propose a relationship between the structures activated during the recent unrest episodes and those responsible for the recent (b3.8–4 ka) volcanism. The combined interpretation of the collected data show that (a) the caldera consists of two sectors separated by a N–S striking faulting zone and (b) the intra-caldera NW–SE faults and eruptive fissures in the central-eastern sector re-activated during the studied unrest episodes and represent possible pathways for the ascent of magma and/or gas to the surface. In this sector, maximum horizontal strain, recent volcanism (3.8–4 ka), active degassing and seismicity concentrate. The fault re-activation is related to the dynamics of the caldera and not to tectonic stress. The deformation fields of the uplift and subsidence episodes are consistent with hydrothermal processes and degassing from a magmatic reservoir that is significantly smaller than the large (∼40 km3) magma chamber responsible for the caldera formation. We provide evidence that the monitoring of the horizontal and vertical components of deformation improves the identification of active, aseismic faults. Accordingly, we suggest that future ground deformation models should include the re-activation of the detected structures.
    Description: This study has been supported by the TELLUS project (Telerilevamento Laboratori Unità di Supporto), which has been developed in the framework of the PODIS project (Progetto Operativo Difesa Suolo) of the Ministero dell'Ambiente e per la Tutela del Territorio e del Mare,and has been funded by the European Union QCS 2000–2006 PONATAS, by INGV-Osservatorio Vesuviano, and by 'Creep' IYPE-UNESCO project.
    Description: Published
    Description: 2373-2383
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 5.5. TTC - Sistema Informativo Territoriale
    Description: JCR Journal
    Description: restricted
    Keywords: PSInSAR ; Fault re-activation ; Campi Flegrei ; Caldera ; 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::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 70
    Publication Date: 2021-06-15
    Description: Public works in progress in the Campanian plain north of Somma-Vesuvius recently encountered the remains of a prehistoric settlement close to the town of Afragola. Rescue excavations brought to light a Bronze Age village partially destroyed and buried by pyroclastic density currents (PDCs) of the Vesuvian Pomici di Avellino eruption (3.8 14C ka BP) and subsequently sealed by alluvial deposits. Volcanological and rockmagnetic investigations supplemented the excavations. Careful comparison between volcanological and archaeological stratigraphies led to an understanding of the timing of the damage the buildings suffered when they were struck by a series of PDCs. The first engulfed the village, located some 14 km to the north of the inferred vent, and penetrated into the dwellings without causing major damage. The buildings were able to withstand the weak dynamic pressure of the currents and deviate their path, as shown by the magnetic fabric analyses. Some later collapsed under the load of the deposits piled up by successive currents. Stepwise demagnetization of the thermal remanent magnetization (TRM) carried by potsherds embedded in the deposits yields deposition temperatures in the order of 260– 320 °C, fully consistent with those derived from pottery and lithic fragments from other distal and proximal sites. The fairly uniform temperature of the deposits is here ascribed to the lack of pervasive air entrainment into the currents. This, in turn, resulted from the lack of major topographical obstacles along the flat plain. The coupling of structural damage and sedimentological analyses indicates that the currents were not destructive in the Afragola area, but TRM data indicate they were still hot enough to cause death or severe injury to humans and animals. The successful escape of the entire population is apparent from the lack of human remains and from thousands of human footprints on the surface of the deposits left by the first PDCs. People were thus able to walk barefoot across the already emplaced deposits and escape the subsequent PDCs. The rapid cooling of the deposits was probably due to both their thinness and heat dissipation due to condensation of water vapour released in the mixture by magma–water interaction.
    Description: Published
    Description: 408–421
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    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::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 71
    Publication Date: 2017-04-04
    Description: Quantifying mercury (Hg) emissions from active volcanoes is of particular interest for better constraining the global cycle and environmental impact of this highly toxic element. Here we report on the abundance of total gaseous (TGM=Hg0 (g)+HgII (g)) and particulate (Hg(p)) mercury in the summit gas emissions of La Soufrière andesitic volcano (Guadeloupe island, Lesser Antilles), where enhanced degassing of mixed hydrothermalmagmatic volatiles has been occurring since 1992 from the Southern summit crater.We demonstrate that Hg in volcanic plume occurs predominantly as gaseous mercury, with a mean TGM/Hg(p) mass ratio of ~63. Combining the mean TGM/H2S mass ratio of the volcanic plume (~3.2×10−6), measured close to the source vent, with the H2S plume flux (~0.7 t d−1), determined simultaneously, allows us to estimate a gaseous mercury emission rate of 0.8 kg yr−1 from La Soufrière summit dome. Somewhat lower TGM/Stot mass ratio in fumarolic gases from the source vent (4.4×10−7) suggests that plume chemical composition is not well represented by the emission source (fumaroles) due to chemical processes prior to (or upon) discharge. Current mercury emission from La Soufrìere volcano represents a very small contribution to the estimated global volcanic budget for this element.
    Description: Published
    Description: 276-282
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Mercury ; Fumaroles ; Volcanic plume ; Trace metals ; Gaseous and particulate mercury ; Emission rate ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 72
    Publication Date: 2017-04-04
    Description: The multi-parametric permanent system (tilt and GPS networks, robotized geodetic station) for monitoring ground deformation at Stromboli volcano was set up in the 1990s and later greatly improved during the effusive event of 2002–2003. Unlike other volcanoes, e.g. Mt. Etna, the magnitude of ground deformation signals of Stromboli is very small and through the entire period of operation of the monitoring system, only two major episodes of deformation, in 1994–1995 and 2000, which did not lead to an eruption but rather pure intrusion, were measured. Similarly to the 2002–2003 eruption, no important deformations were detected in the months before the 2007 eruption. However, unlike the 2002–2003 eruption, GPS and tilt stations recorded a continuous deflation during the entire 2007 eruption, which allowed us to infer a vertical elongated prolate ellipsoidal source, centered below the summit craters at depth of about 2.8 km b.s.l. Due to its geometry and position, this source simulates an elongated plumbing system connecting the deeper LP magma storage (depth from 5 to 10 km) with the HP shallower storage (0.8–3 km), both previously identified by petrologic and geochemical studies. This result represents the first contribution of geophysics to the definition of the plumbing system of Stromboli at intermediate depth. Finally, no deformation due to the plumbing system was measured for a long time after the end of the eruption. Meanwhile, the new terrestrial geodetic monitoring system installed within the Sciara del Fuoco, on the lava fan formed during the eruption, indicated that during the first months after the end of the eruption the ground velocity progressively decreased in time, suggesting that part of the deformation was due to the thermal contraction of the lava flow.
    Description: Published
    Description: 172-181
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; Ground Deformation ; source modelling ; flank instability ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. 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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  • 73
    Publication Date: 2017-04-04
    Description: Focusing on the Island of Stromboli, this research investigates whether airborne remote sensing systems, such as those based on digital photogrammetry and laser scanner sensors, can be adopted to monitor slope deformation and lava emplacement processes in active volcanic areas. Thanks to the capability of extracting accurate topographic data and working on flexible time schedules, these methods can be used to constrain the regular and more frequent measurements derived from satellite observations. This work is dedicated to the monitoring of Stromboli's volcanic edifice which is beneficial when obtaining quantitative data on the geometry of deformation features and the displaced (failures and landslides) and emplaced (lava flows) volumes. In particular, we focus on the capability of extracting average effusion rates from volume measurements that can be used to validate or integrate satellite-derived estimates. Since 2001, a number of airborne remote sensing surveys, namely Digital Photogrammetry (DP) and Airborne Laser Scanning (ALS), have been carried out on Stromboli's volcano to obtain high resolution Digital Elevation Models (DEM) and orthophotos with sub-meter spatial resolution and a time schedule suitable for monitoring the morphological evolution of the surface during the quiescent phases. During the last two effusive eruptions (2002–2003 and 2007) the surface modifications, created on the Sciara del Fuoco slope and on the crater area as a consequence of effusive activity, were quantified and monitored using the same methodologies. This work, which is based on the results obtained from the multi-temporal quantitative analysis of the data collected from 2001 to 2007, mainly focuses on the 2007 eruption but also accounts for analogies and differences regarding the 2002–2003 event. The 2007 eruption on the Sciara del Fuoco slope from 27 February until 2 April, produced a compound lava field including a lava delta on the shoreline, discharging most of the lava into the sea. The comparison of the 2007 DEMs with a pre-eruption surface (2006 LIDAR survey) allowed for the evaluation of the total lava volume that accumulated on the subaerial slope while two syn-eruption DEMs were used to calculate the average effusion rates during the eruption. Since the evolution of a lava field produced during an eruption can be seen as a proxy for the magma intrusion mechanism, hypotheses are formulated on the connection between the lava discharge and the instabilities suffered by the slope.
    Description: Published
    Description: 201-213
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Slope deformation ; Effusive activity ; Aerial surveys ; Digital elevation model ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 74
    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 lava flow from a fracture cutting the flank of the NE cone, which rapidly reached the sea. The eruption had been heralded by an increase in the amplitude of tremor and flank movement since at least the 14th of February. Short-term precursors were an increase in the rate of occurrence of small landslides within the “Sciara del Fuoco” scar on the North-western flank of the volcano. A new effusive vent opened at 18.30 GMT on the Sciara del Fuoco at an height of 400 m asl. The new lava emission caused the sudden termination of the summit flow and initiated a period of non-stationary lava outpouring which 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 of March, the increase in lava outpouring, monitored by a thermal camera, heralded by 9 min the occurrence of a violent paroxysmal explosion with the formation of an impulsive eruption column and the emission of small pumices mingled with black scoriae. The pumice had a bulk composition similar to that of the lava and of the black scoriae, but with a distinct lower content of phenocrysts. A similar feature has been repeatedly observed during the major explosive paroxysms of Stromboli. Short term precursors of the paroxysm were recorded by strainmeter and tiltmeter stations. The volcano monitoring activity has been made by a joint team of researchers from the INGV sections of Catania, Napoli, Palermo and Rome, along with researchers from the Universities of Florence, Pisa, Roma Tre, and Palermo. The scientific activity was coordinated by a Synthesis Group made up by scientists responsible for the different monitoring techniques of INGV and Universities and by the volcanic experts of Commissione Nazionale Grandi Rischi of the Prime Minister Office (Civil Protection Department). The group made a daily evaluation of the state of the volcano and transmitted its recommendations to the Civil Protection Department (DPC). Several prevention measures were adopted by DPC, the main of which were the evacuation of the coast zone when strong acceleration of the Sciara del Fuoco slope motion (occurred twice) could led to a dangerous tsunami by flank collapse (as last occurred on 30 December 2002) and four days before the 15 March paroxysm when access was prohibited to the part of the volcano above 290 m asl.
    Description: Published
    Description: 123–130
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli volcano ; 2007 eruption ; scientific emergency management ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 75
    Publication Date: 2017-04-04
    Description: Dynamic accumulation chamber methods have been extensively used to estimate the total output of CO2 released from active volcanic area. In order to asses the performance and reliability of a closed dynamic system several tests were carried out with different soil permeabilities and soil CO2 fluxes. A special device was used to create a constant one-dimensional CO2 flux through a soil column with a known permeability. Three permeabilities were investigated, ranging between 3.6 × 10− 2 and 3.5 × 10 μm2, as were several CO2 fluxes (ranging between 1.1 × 10− 6 and 6.3 × 10− 5 kg m− 2 s− 1). The results highlight that the accuracy of soil CO2 flux measurements strictly depends on the soil gas permeability and the soil CO2 flux regimen. Generally chamber measurements underestimate CO2 fluxes at low soil permeability and low soil CO2 fluxes, whereas appreciable overestimations occur for high permeability soil, especially for high soil CO2 fluxes. Other tests carried out with different settings for the measurement device, such as the chamber volume and the flux of the pump used to recirculate air through the chamber and the gas analyzer (recirculation flux), revealed a strong dependence of the closed dynamic chamber measurements on the recirculation flux. Low recirculation fluxes (0.2–0.4 l min− 1) decreased the performance of the measurement system, causing underestimations of the actual soil CO2 flux, whereas higher values (0.6–1.0 l min− 1) resulted in overestimations, especially for elevated soil CO2 fluxes. An empirical equation was deduced to allow accumulation chamber fluxes to be calculated very accurately based on soil gas permeabilities measured in the field.
    Description: Published
    Description: 387-393
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Soil CO2 flux measuraments ; Closed dynamic chamber ; soil gas permeability ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 76
    Publication Date: 2017-04-04
    Description: Major results of post-intrusive GPS monitoring of the five months encompassing and following the onset of 2002-03 Mt. Etna eruption are presented and discussed here. The overall ground deformation pattern is characterized by a time-dependent relaxation function. We evaluated two different parameterizations of relaxation functions, each one linked to a different relaxation process: i) viscoelastic relaxation and ii) after-slip mechanism. The former indicated that the process occurred within a weak layer characterized by viscosity values ranging between 7.1 • 1014 Pa s and 1.3 • 1015 Pa s. The latter evidenced that frictional processes occurred beneath a layer of velocity-strengthening having a thickness with values ranging between 0.4 km and 1.7 km. Either model may explain the observed time-dependent deformation, both from the statistical point of view and the comparison with geologic and seismic information. Although we are unable to favour one model rather than the other, these results indicate that the mechanism, responsible for the observed post-intrusive deformation, occurs within a sliding “zone” located inside the clayey sedimentary basement.
    Description: This study was undertaken with financial support from the FLANK project (DPC-INGV 2008 - 2010 contract)
    Description: Published
    Description: 300-311
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: 2002-03 Mt. Etna eruption ; Post-intrusive relaxation ; Viscoelastic ; After-slip ; Rheology ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 77
    Publication Date: 2017-04-04
    Description: On February 27, 2007 a new eruption started at Stromboli that lasted until April 2 and included a paroxysmal explosion on March 15. Geochemical monitoring carried out over several years revealed some appreciable variations that preceded both the eruption onset and the explosion. The carbon dioxide (CO2) flux from the soil at Pizzo Sopra La Fossa markedly increased a few days before the eruption onset, and continued during lava effusion to reach its maximum value (at 90,000 g m−2 d−1) a few days before the paroxysm. Almost contemporarily, the δ13CCO2 of the SC5 fumarole located in the summit area increased markedly, peaking just before the explosion (δ13CCO2~−1.8‰). Following the paroxysm, helium (He) isotopes measured in the gases dissolved in the basal thermal aquifer sharply increased. Almost contemporarily, the automatic station of CO2 flux recorded an anomalous degassing rate. Also temperatures and the vertical thermal gradient, which had been measured since November 2006 in the soil at Pizzo Sopra La Fossa, showed appreciable variabilities that lasted until the end of the eruption. The geochemical variations indicated the degassing of a new batch of volatile-rich magma that preceded and probably fed the paroxysm. The anomalous 3He/4He ratio suggested that the ascent of a second batch of volatile-rich magma toward the surface was probably responsible of the resumption of the ordinary activity. A comparison with the geochemical variations observed during the 2002–2003 eruption indicated that the 2007 eruption was less energetic.
    Description: Published
    Description: 246-254
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: geochemistry ; eruption ; dissolved gases ; Stromboli ; volcanic activity ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 78
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 79
    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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  • 80
    Publication Date: 2017-04-04
    Description: The Campi Flegrei caldera is an active and restless volcano in the densely inhabited Neapolitan area of southern Italy. Because of the very high value (lives, properties, infrastructures, etc.) exposed to potential volcanic hazards, it is one of the areas at highest volcanic risk on Earth. In such a situation we have made an attempt to contribute to assessment of its volcanic hazards by providing a quantitative probabilistic longterm forecast of style and size of the next eruption. We have evaluated the most relevant physical parameters of the 22 explosive eruptions of the Campi Flegrei caldera over the past 5 ka. This time span has been taken as the reference period for volcanic hazards assessment on the basis of the volcanic and deformation history of the caldera. The evaluated parameters include dispersal, volume and density of the pyroclastic deposits, volume of erupted magma, total erupted mass, and eruption magnitude. The obtained results permit a size classification of the explosive eruptions, which are grouped into three sizes: small, medium, and large. On the basis of the reconstructed eruption dynamics, we have considered a type event(s) representative of each size class and hypothesized the style of the next event. An effusive eruption will likely generate a dome or very small lava flows, while an explosive event of any size very probably will produce particles fallout and flowage of pyroclastic density currents. Using a Bayesian inference procedure, we have assigned a conditional probability of occurrence to each of the eruption size classes. A small-size explosive eruption is the most likely event with a probability of about 60%; a large-size explosive eruption is the least likely event with a probability of about 4%; a medium-size explosive eruption has a probability of occurrence of about 25%; an effusive eruption has about 11% probability of occurrence.
    Description: Published
    Description: 265–276
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: volcanic hazards assessment ; eruption size ; eruption style ; Campi Flegrei caldera ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 81
    Publication Date: 2017-04-04
    Description: Routine measurements of SO2 flux using the traverse method on Mt. Etna (Italy) were augmented in late 2004 when an array of automatic scanning ultraviolet spectrometers was installed. Each instrument allows one SO2 scan to be recorded every ~6 min. Here we report the methods that we developed to automatically and robustly transform SO2 profiles into SO2 flux data. Radian geometry and Fast Fourier Transform algorithm were used for reducing plume cross-sections and for discriminating between volcanic plumes from those produced by water vapour clouds. Uncertainty in flux measurements depends on the accuracy of plume height estimation, on assumptions concerning plume-geometry, and on the quality of the retrieved SO2 amounts. We compare 3 years of flux measurements made using both the automated network and “conventional” traverse methods beneath the plume.We found a good agreement between the datasets, both in terms of magnitude and in temporal variations. These results validate the Etna SO2 flux monitoring system. Emission rates are available to the 24-hour manned operations room via intranet, providing real-time information on degassing rates and plume location.
    Description: (1)Sviluppo di sistemi di monitoraggio Dipartimento di Protezione Civile della Regione Sicilia, (2)INGV (Istituto Nazionale di Geofisica e Vulcanologia, sezione di Catania — Italy), (3)NOVAC (Network for Observation of Volcanic and Atmospheric Change)EU-funded Sixth Framework Programme project 18354. ()4 UK NERC National Centre for Earth Observation via the “Dynamic Earth and geo-hazards”.
    Description: Published
    Description: 76-83
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: sulphur dioxide, scanning spectrometer, car-based traverse, DOAS, Mt. Etna, volcano surveillance ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 82
    Publication Date: 2017-04-04
    Description: The recent development of fixed networks of scanning ultraviolet spectrometers for automatic determination of volcanic SO2 fluxes has created tremendous opportunities for monitoring volcanoes but has brought new challenges in processing (and interpreting) the copious data flow they produce. A particular difficulty in standard implantation of differential optical absorption (DOAS) methods is the requirement for a clear-sky (plume-free) background spectrum. Our experience after four years of measurements with two UV scanner networks on Etna and Stromboli shows that wide plumes are frequently observed, precluding simple selection of clear-sky spectra. We have therefore developed a retrieval approach based on simulation of the background spectrum. We describe the method here and tune it empirically by collecting clear, zenith sky spectra using calibration cells containing known amounts of SO2. We then test the performance of this optimised retrieval using clear-sky spectra collected with the same calibration cells but for variable scan angles, time of day, and season (through the course of 1 year), finding acceptable results (~12% error) for SO2 column amounts. We further illustrate the analytical approach using spectra recorded at Mt. Etna during its July 2006 eruption. We demonstrate the reliability of the method for tracking volcano dynamics on different time scales, and suggest it is widely suited to automated SO2-plume monitoring
    Description: (1)FIRB-MIUR “Simulazione dei flussi lavici con gli automi cellulari” N. RBAU01RMZ4_002 and “Sviluppo di sistemi di monitoraggio' Dipartimento di Protezione Civile della Regione Sicilia, INGV(Istituto Nazionale di Geofisica e Vulcanologia, sezione di Catania – Italy). (2) EU-funded Sixth Framework Programme project 18354 “NOVAC” (Network forObservation of Volcanic and Atmospheric Change). (3) Leverhulme Trust fellowship
    Description: Published
    Description: 141-153
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Volcanic Gas Monitoring, Scanning spectrometer network, DOAS, Ultraviolet Spectroscopy, Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 83
    Publication Date: 2017-04-04
    Description: The Astroni volcano was built through seven eruptions that generated pyroclastic deposits and lava domes within the Campi Flegrei caldera (southern Italy) 4.1–3.8 ka BP. Whole-rock geochemical and B–Sr–Nd isotopic investigations were carried out on representative samples of all seven eruptions. The products vary from tephriphonolites to phonolites, and from latites to trachytes. They show textural, mineralogical and isotopic evidence of disequilibrium, including distinct clinopyroxene populations, rounded and/or resorbed plagioclase and alkali-feldspar, and reverse-zoned phenocrysts of all these mineral phases. The Sr, Nd and B isotopic composition of whole rocks is variable and correlated with the degree of chemical evolution, suggesting open-system processes in addition to fractional crystallisation. Moreover, significant Sr-isotopic disequilibrium between the phenocrysts and glass has been documented for one sample. The chemostratigraphy of the products indicates that Astroni eruptions 1 through 5 were fed by magmas of trachytic to phonolitic composition that were less enriched in radiogenic Sr and 11B up-section. This variability has been interpreted as the result of mingling between at least two distinct magmatic endmembers, one more evolved and the other less evolved. Another heterogeneous batch of magma, resulting from almost complete mixing between the same two end-members, was drained during eruptions 6 and 7. The more evolved end-member, characterised by 87Sr/86Sr≥0.7075, 143Nd/144Nd≤0.51247 and δ11B≥−8‰, was very similar to the magma that fed the final phases of the Agnano–Monte Spina eruption, which occurred a few centuries earlier in the Astroni vent area. The less evolved end-member had 87Sr/ 86Sr≤0.70726, 143Nd/144Nd≥0.51251 and δ11B≤10‰, and was likely derived by fractional crystallisation of a mantle-derived magma. An abrupt decrease in both the Sr isotope ratio and the Th content, detected at the transition between Unit 4 and 5, suggests that another magma with a 87Sr/86Sr ratio intermediate between those of the two identified end-members may have been involved in Astroni activity. The more evolved endmember is interpreted as a residue of the Agnano–Monte Spina eruption that was invaded by either the intermediate or the less evolved magmatic end-member, promoting mingling and triggering Astroni activity. This study of Astroni provides insights for both short- and long-term volcanic hazard assessment, as the Astroni volcano is the best example of a very close sequence of eruptions from the same vent area in the Campi Flegrei caldera.
    Description: Published
    Description: 135–151
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Campi Flegrei caldera ; B–Sr–Nd isotope geochemistry ; Magma mingling/mixing ; Chemostratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 84
    Publication Date: 2022-04-22
    Description: Ground deformations are observed in connection with volcanic activity, and therefore, geodetic monitoring can provide significant indication of changes of equilibrium conditions. The aim of this paper is to study the deformation of Mount Vesuvius (Italy) caused by overpressure sources at various depths, using a commercial (Ansys) 3D finite element code, in the framework of linear elastic isotropic material behavior. Both homogenous and heterogeneous media with carbonate basement were analyzed to understand the influence of topography on the ground deformations. The topography of the Somma-Vesuvius was taken into account, using a digital terrain model, and the carbonate basement was schematically modelled by assuming two horizontal layers with different Young moduli. The presence of a strong deviation from axially symmetric pattern of the displacement field, and of small subsidence areas, was found. These characteristics are completely unknown from the simple Mogi model and by simplified topography model, as verified by ad hoc simulations. These preliminary results, showing areas of the volcanic edifice experiencing high deformation, can improve the determination of the sources of deformations, i.e. the most relevant problem in the volcano monitoring. Moreover, the knowledge of the deformation pattern, including the topography effects, can provide significant indications to optimize the location of sensors and the characteristics needed to design an efficient and reliable geodetic monitoring network able to detect shallow intrusion events.
    Description: Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento della Protezione Civile
    Description: Published
    Description: 178-186
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Ground deformations ; Geodetic monitoring ; Topography ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 85
    Publication Date: 2020-10-29
    Description: Two sets of cooling experiments were run at atmospheric conditions for two anhydrous starting latitic and trachytic melts: 1) five cooling rates (25, 12.5, 3, 0.5, and 0.125 °C/min) between 1300° and 800 °C, and 2) a 11 0.5 °C/min cooling rate from 1300 °C with quench temperatures at 1200°, 1100°, 1000° and 900 °C. Trachytic run-products are invariably glassy. Nucleation is also suppressed in the latitic run-products at the three highest 13 cooling rates. Conversely, in the 0.5 and 0.125 °C/min runs, latites have a crystal content of 90 vol.%. The 14 phases are: plagioclase, clinopyroxene, glass and iron-bearing oxide (in order of abundance). The variable 15 quench temperatures, investigated by coupling experiments with Pt-wire and Pt- capsule sample containers inset 2,again did not produce crystallization of trachyte, whereas latitic samples are characterized by 10 vol.% of oxides, pyroxenes and plagioclase (in order of appearance), at temperature b1000 °C. Effects of (preferential) heterogeneous nucleation on sample holders, of superheating degree, and chemical species loss during cooling are absent for both melt compositions. The difference of solidification paths between these two silicate melts can be ascribed only to their small chemical differences. In comparison with calculated equilibrium conditions all the experimental latitic and trachytic run-products revealed strong kinetic effects, interpretable in the light of the nucleation theory. The glass- forming ability (GFA) of trachyte is higher, whereas their critical cooling rate (Rc) is lower (b0.125 °C/min), in comparison to latitic melts (RcN0.5 °C/min). The experimental results carried out in this study can be applied to lava flows and domes; trachytic lavas are able to flow for longer period with respect to latitic ones in a metastable condition. Glass-rich terrestrial lavas, i.e. obsidians, can be the result of sluggish nucleation kinetics due to the relative high polymerisation of evolved silicate melts.
    Description: Published
    Description: 91-101
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: crystallization ; lava flows ; 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::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 86
    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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  • 87
    Publication Date: 2021-01-07
    Description: The CO2 degassing process from a large area on the Tyrrhenian side of central Italy, probably related to the input into the upper crust of mantle fluids, was investigated in detail through the geochemical study of gas emissions and groundwater. Mass-balance calculations and carbon isotopes show that over 50% of the inorganic carbon in regional groundwater is derived from a deep source highlighting gas−liquid separation processes at depth. The deep carbonate−evaporite regional aquifer acts as the main CO2 reservoir and when total pressure of the reservoir fluid exceeds hydrostatic pressure, a free gas phase separates from the parent liquid and escapes toward the surface generating gas emissions which characterise the study area. The distribution of the CO2 flux anomalies and the location of high PCO2 springs and gas emissions suggest that the storage and the expulsion of the CO2 toward the atmosphere are controlled by the geological and structural setting of the shallow crust. The average CO2 flux and the total amount of CO2 discharged by the study area were computed using surface heat flow, enthalpy and CO2 molality of the liquid phase circulating in the deep carbonate−evaporite aquifer. The results show that the CO2 flux varies from 1×104 mol y−1 km−2 to 5×107 mol y−1 km−2, with an average value of 4.8×106 mol y−1 km−2, about five times higher than the value of 1×106 mol y−1 derived by Kerrick et al. [Kerrick, D.M., McKibben, M.A., Seward, T.M., Caldeira, K., 1995. Convective hydrothermal CO2 emission from high heat flow regions. Chem. Geol. 121, 285–293] as baseline for terrestrial CO2 emissions. The total CO2 discharged from the study area is 0.9×1011 mol y−1, confirming that Earth degassing from Tyrrhenian central Italy is a globally relevant carbon source
    Description: Published
    Description: 89–102
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: Earth degassing ; carbon dioxide ; CO2 flux ; groundwater ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 88
    Publication Date: 2021-05-17
    Description: Papandayan is a stratovolcano situated in West Java, Indonesia. Since the last magmatic eruption in 1772,only few hydrothermal explosions have occurred. An explosive eruption occurred in November 2002 and ejected ash and altered rocks. The altered rocks show that an advanced argillic alteration took place in the hydrothermal system by interaction between acid fluids and rocks. Four zones of alteration have been defined and are limited in extension and shape along faults or across permeable structures at different levels beneath the active crater of the volcano. At the present time, the activity is centered in the northeast crater with discharge of low temperature fumaroles and acid hot springs. Two types of acid fluids are emitted in the crater of Papandayan volcano: (1) acid sulfate-chloride waters with pH between 1.6 and 4.6 and (2) acid sulfate waters with pH between 1.2 and 2.5. The water samples collected after the eruption on January 2003 reveal an increase in the SO4/Cl and Mg/Cl ratios. This evolution is likely explained by an increase in the neutralization of acid fluids and tends to show that water–rock interactions were more significant after the eruption. The evolution in the chemistry observed since 2003 is the consequence of the opening of new fractures at depth where unaltered (or less altered) volcanic rocks were in contact with the ascending acid waters. The high δ34S values (9–17‰) observed in acid sulfatechloride waters before the November 2002 eruption suggest that a significant fraction of dissolved sulfates was formed by the disproportionation of magmatic SO2. On the other hand, the low δ34S (−0.3–7‰) observed in hot spring waters sampled after the eruption suggest that the hydrothermal contribution (i.e. the surficial oxidation of hydrogen sulfide) has increased.
    Description: Published
    Description: 276-286
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: Papandayan volcano ; Indonesia ; phreatic eruption ; hydrothermal system ; fluid geochemistry ; advanced argillic alteration ; gas geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 89
    Publication Date: 2020-11-17
    Description: Recent seismic swarms and hydrothermal activity suggest that the Quaternary volcanic complex of the Alban Hills may pose a threat to the city of Rome. A 350m scientific borehole was therefore drilled into this volcanic area to elucidate its inner structure for the first time. Wire-line logs were run in the borehole in order to characterize the physical properties of the rocks and their variations with depth. In particular, a detailed sonic log was run to measure the P-wave velocity from the well-head down to 110 m. To further investigate velocity changes, we carried out laboratory measurements of P and S elastic wave velocities and fluid permeability at effective pressures up to 70 MPa during both increasing and decreasing pressure cycles on selected core samples representative of the main volcanic units. Specifically, we studied samples from two pyroclastic units representative of two classes of volcanic deposits that are representative of the whole succession: (i) a coarse-grained, well-lithified facies (Pozzolane Rosse unit), containing abundant mm-to-cm lava clasts and crystals; and (ii) a fine-grained, matrix-supported pyroclastic deposit (Tufo Pisolitico di Trigoria unit), with rare lithic lava clasts and sparse pumice. Elastic wave velocities reveal significant differences between units and indicate how, within the same lithology, the different degree of lithification and presence of clasts can affect significantly physical property values. The mean laboratory value of the Pwave velocity for Pozzolane Rosse and Tufo Pisolitico di Trigoria units is respectively of 3.75 and 3.2 km/s at an effective pressure equivalent to that at the depth at which the sonic velocity was measured. Under increasing effective pressure a profound influence on the transport properties is observed. Permeability ranges from the order of 10−18 m2 for the Pozzolane Rosse unit to the order of 10−15 m2 for the Tufo Pisolitico di Trigoria unit, in good agreement with the shallow aquifer circulating in the shallower units.
    Description: Published
    Description: 161-169
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Scientific borehole ; Volcanic rocks ; Physical properties ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 90
    Publication Date: 2020-11-16
    Description: Volcanic edifices, such as Mt. Etna (Italy), are commonly subject to repeated cycles of stress over time due to the combination of magma emplacement from deep reservoirs to shallow depths and superimposed tectonic stresses. Such repeated stress cycles lead to anisotropic deformation and an increase in the level of crack damage within the rocks of the edifice and hence changes to their elastic moduli, which are a key parameter for reliable modelling of deformation sources. We therefore report results of changes in elastic moduli measured during increasing amplitude cyclic stressing experiments on dry and water-saturated samples of Etna basalt. In all experiments, the Young’s modulus decreased by approximately 30% over the total sequence of loading cycles, and the Poisson’s ratio increased by a factor of approximately 3 ± 0.5. Microseismicity, in terms of acoustic emission (AE) output, was also recorded throughout each experiment. Our results demonstrate that AE output only re-commences during any loading cycle when the level of stress where AE ceased during the unloading portion of the previous cycle is exceeded; a manifestation of the Kaiser stress-memory effect. In cycles where no AE output is generated, we also observe no change in elastic moduli. This result is observed for both mechanical and thermal stressing. Our results are interpreted in relation to measurements of volcano-tectonic seismicity and deformation at Mt. Etna volcano.
    Description: Published
    Description: 153-160
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: rock mechanics, elastic moduli, Etna basalt ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 91
    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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  • 92
    Publication Date: 2017-04-04
    Description: The Albano Lake is the deepest volcanic lake in Italy (−167 m) and fills the youngest maar of the quiescent Colli Albani volcano. The lake has undergone significant level changes and lahar generating overflows occurred about 5800 yrs B.P. and likely in 398 b.C., when Romans excavated a tunnel drain through the maar wall. Hazardous lake rollovers and CO2 release are still possible because the Albano volcano shows active ground deformation, gas emission and periodic seismic swarms. On November 2005, the first high resolution bathymetric survey of the Albano Lake was performed. Here we present the results provided by a Digital Elevation Model and 2-D and 3-D images of the crater lake floor, which is made by coalescent and partly overlapping craters and wide flat surfaces separated by some evident scarps. Submerged shorelines are identified at depths between −20 m and −41 m and indicate the occurrence of significant lake level changes, likely between 7.1 and 4.1 ka. The current lake volume is ~447.5×106 m3 and the total quantity of dissolved CO2 is 6850 t estimated by chemical analyses of samples collected on May 2006. A decrease of nearly one order of magnitude of the CO2 dissolved in the lake water below −120 m, observed from December 1997 to May 2006 (from 4190 to 465 t respectively), has been attributed to lake water overturn. The observed oscillations of the dissolved CO2 concentrations justify the efforts of monitoring the chemical and physical characteristics of the lake. At present the quantity of dissolved CO2 is very far from saturation and Nyostype events cannot presently occur.
    Description: DPC-INGV Project V3_1
    Description: Published
    Description: 258–268
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Albano maar ; lake bathymetry ; geochemistry ; crater lake hazard ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 93
    Publication Date: 2017-04-04
    Description: El Chichón volcano (Chiapas, Mexico) erupted violently in March–April 1982, breaching through the former volcano–hydrothermal system. Since then, the 1982 crater has hosted a shallow (1–3.3 m, acidic (pH ∼ 2.2) and warm (∼ 30 °C) crater lake with a strongly varying chemistry (Cl/SO4=0–79 molar ratio). The changes in crater lake chemistry and volume are not systematically related to the seasonal variation of rainfall, but rather to the activity of near-neutral geyser-like springs in the crater (Soap Pool). These Soap Pool springs are the only sources of Cl for the lake. Their geyser-like behaviour with a long-term (months to years) periodicity is due to a specific geometry of the shallow boiling aquifer beneath the lake, which is the remnant of the 1983 Cl-rich (24,000 mg/l) crater lake water. The Soap Pool springs decreased in Cl content over time. The zero-time extrapolation (1982, year of the eruption) approaches the Cl content in the initial crater lake,meanwhile the extrapolation towards the future indicates a zero-Cl content by 2009±1. This particular situation offers the opportunity to calculate mass balance and Cl budget to quantify the lake–spring system in the El Chichón crater. These calculations show that the water balance without the input of SP springs is negative, implying that the lake should disappear during the dry season. The isotopic composition of lake waters (δD and δ18O) coincide with this crater lake-SP dynamics, reflecting evaporation processes and mixing with SP geyser and meteoric water. Future dome growth, not observed yet in the post-1982 El Chichón crater, may be anticipated by changes in lake chemistry and dynamics.
    Description: Published
    Description: 237–248
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: El Chichón volcano ; crater lake–Spring dynamics ; fluid geochemistry ; stable isotopes ; monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 94
    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: In press
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; diffuse CO2 fluxes ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 95
    Publication Date: 2017-04-04
    Description: We have developed two new quantitative approaches to calculate temperatures in hydrothermal reservoirs by using the CO2-CH4-CO-H2 gaseous system and to model selective dissolution of CO2-H2S-N2-CH4-He-Ne mixtures in fresh and/or air saturated seawater. The anomalous outgassing starting November 2003 from the submarine exhalative system offshore Panarea island (Italy), was the occasion to apply such approaches to the extensive collection of volcanic gases. Gas geothermometry suggest the presence of a deep geothermal system at temperature up to 350°C and about 12 mol% CO2 in the vapor, which feeds the submarine emissions. Based on the fractional dissolution model, the rising geothermal vapor interacts with air-saturated seawater at low depths, dissolving 30-40% CO2 and even more H2S, modifying the pH of the aqueous solution and stripping the dissolved atmospheric volatiles (N2, Ne). Interaction of the liquid phase of the thermal fluids with country rocks, as well extensive mixing with seawater, have been also recognized and quantified. The measured output of hydrothermal fluids from Panarea exhalative field [1] accounts for the involvement of volatiles from an active degassing magma, nonetheless the climax of the investigated phenomenon is probably overcome and the system is new tending towards a steady-state. Our quantitative approaches allow us to monitor the geochemical indicators of the geothermal physico-chemical conditions and their potential evolution towards phreatic events or massive gas releases, which certainly are the main hazards to be expected in the area. The event at Panarea has in fact highlighted how hydrothermal systems can exhibit dramatic and sudden changes of their physico-chemical conditions and rate of fluid release, as a response to variable activity of feeding magmatic systems.
    Description: Published
    Description: Copenhagen
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: open
    Keywords: Submarine ; geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Extended abstract
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  • 96
    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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  • 97
    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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  • 98
    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)
    Type: article
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  • 99
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 100
    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: Published
    Description: 393-416
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: reserved
    Keywords: hydrothermal fluids ; unrest ; modeling ; caldera ; monitoring ; volcanic hazard ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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