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  • 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous  (32)
  • Mt. Etna  (20)
  • Elsevier Science Limited  (29)
  • Springer  (13)
  • Wiley-Blackwell  (4)
  • EGU  (2)
  • ELSEVIER  (2)
  • Blackwell Publishing Ltd
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • 2010-2014  (38)
  • 2005-2009  (12)
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  • 1
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    Spatial probability distribution of future volcanic eruptions at El Hierro Island (Canary Islands, Spain) (2014)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The 2011 submarine eruption that took place in the proximity of El Hierro Island (Canary Islands, Spain) has raised the need to identify the most likely future emission zones even on volcanoes characterized by low frequency activity. Here, we propose a probabilistic method to build the susceptibility map of El Hierro, i.e. the spatial distribution of vent opening for future eruptions, based on the probabilistic analysis of volcano-structural data of the Island collected through newfieldworkmeasurements, bathymetric information, as well as analysis of geological maps, orthophotos and aerial photographs. These data have been divided into different datasets and converted into separate and weighted probability density functions, which were included in a non-homogeneous Poisson process to produce the volcanic susceptibility map. The most likely area to host new eruptions in El Hierro is in the south-western part of the West rift. High probability locations are also found in the Northeast and South rifts, and along the submarine parts of the rifts. This map represents the first effort to deal with the volcanic hazard at El Hierro and can be a support tool for decision makers in land planning, emergency measures and civil defense actions.
    Beschreibung: This work has been partially funded by the Spanish Geological Survey (IGME) through the MODEX Project (directed by Luis Laín) and a Research Grant for LB, and the Research grant program “Innova Canarias 2020®” from the “Fundación Universitaria de Las Palmas”.
    Beschreibung: Published
    Beschreibung: 21-30
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: 3V. Dinamiche e scenari eruttivi
    Beschreibung: 4V. Vulcani e ambiente
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Susceptibility ; Volcanic hazard ; Eruptive vent ; Volcano-tectonics ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 2
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    Volcanic hot spot detection from optical multispectral remote sensing data using artificial neural networks (2014)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: This paper describes an application of artificial neural networks for the recognition of volcanic lava flow hot spots using remote sensing data. Satellite remote sensing is a very effective and safe way to monitor volcanic eruptions in order to safeguard the environment and the people affected by such natural hazards. Neural networks are an effective and well-established technique for the classification of satellite images. In addition, once well trained, they prove to be very fast in the application stage. In our study a back propagation neural network was used for the recognition of thermal anomalies affecting hot lava pixels. The network was trained using the three thermal channels of the Advanced Very High Resolution Radiometer (AVHRR) sensor as inputs and the corre- sponding values of heat flux, estimated using a two thermal component model, as reference outputs. As a case study the volcano Etna (Eastern Sicily, Italy) was chosen, and in particular the effusive eruption which took place during the month of 2006 July. The neural network was trained with a time-series of 15 images (12 nighttime images and 3 daytime images) and validated on three independent data sets of AVHRR images of the same eruption and on two relative to an eruption occurred the following month. While for both nighttime and daytime validation images the neural network identified the image pixels affected by hot lava with a 100 per cent success rate, for the daytime images also adjacent pixels were included, apparently not interested by lava flow. Despite these performance differences under different illumination conditions, the proposed method can be considered effective both in terms of classification accuracy and generalization capability. In particular our approach proved to be robust in the rejection of false positives, often corresponding to noisy or cloudy pixels, whose presence in multispectral images can often undermine the performance of traditional classification algorithms. Future work shall address application of the proposed method to data acquired with a high temporal resolution, such as those provided by the spinning enhanced visible and infrared imager sensor on board the Meteosat second generation geostationary satellite.
    Beschreibung: Published
    Beschreibung: 1525-1535
    Beschreibung: 5V. Sorveglianza vulcanica ed emergenze
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Image processing ; Neural networks ; fuzzy logic ; Remote sensing of volcanoes ; Hot-spot detection ; 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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  • 3
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    The 2011-2012 summit activity of Mount Etna: birth, growth and products of the new SE crater. (2014)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Between January 2011 and April 2012, the Southeast Crater (SEC) on Mount Etna was the site of 25 episodes of lava fountaining, which led to the construction of a new pyroclastic cone on the eastern flank of the SEC. During these episodes lava overflows reached 4.3 km in length with an area of 3.19 km2 and a volume of 28 x 106 m3. The new cone, informally called New Southeast Crater (NSEC), grew over a pre-existing subsidence depression (pit crater), which had been formed in 2007-2009. The evolution of the NSEC cone was documented from its start by repeated GPS surveys carried out both from a distance and on the cone itself, and by the acquisition of comparison photographs. These surveys reveal that after the cessation of the lava fountains in April 2012, the highest point of the NSEC stood 190 m above the pre-cone surface, while the cone volume was about 19 x 106 m3, representing 38 % of the total (bulk) volume of the volcanic products including pyroclastic fallout erupted in 2011-2012, which is 50 x 106 m3 (about 33 x 106 m3 dense-rock equivalent). Growth of the new cone took place exclusively during the paroxysmal phases of the lava fountaining episodes, which were nearly always rather brief (on the average 2 hours). Overall, the paroxysmal phases of all 25 episodes represent 51 hours of lava fountaining activity – the time needed to build the cone. This is the fastest documented growth of a newborn volcanic cone both in terms of volume and height. Mean effusion rates during the lava fountaining episodes on 20 August 2011 (E11), as well as 12 and 24 April 2012 (E24 and E25) exceeded 500 m3/s (with maximum rates of 980 m3/s during E11) and thus they are among the highest effusion rates ever recorded at Etna. The composition of the erupted products varies in time, reflecting different rates of magma supply into the shallow feeding system, but without notable effects on the eruptive phenomenology. This implies that the dynamics leading to the episodic lava fountaining was largely, though not entirely, controlled by the repeated formation and collapse of a foam layer in the uppermost portion of the magmatic reservoir of the NSEC.
    Beschreibung: Published
    Beschreibung: 10-21
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Etna, summit eruptions; scoria cone growth; lava and tephra volume; collapsing foam model ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    Evidence of active subsidence at Basiluzzo island (Aeolian islands, southern Italy) inferred from a Roman age wharf (2014)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: The Aeolian Arc (Southern Tyrrhenian Sea, Italy) is one of the most active volcanic areas of the Mediterranean basin, affected by volcanic/hydrothermal and seismic activity. Ancient populations settled this region since historical times, building coastal installations which currently are valuable archaeological indicators of relative sea level changes and vertical land movements. In this study we show and discuss data on the relative sea level change estimated from a submerged wharf of Roman age dated between 50 B.C. and 50 A.D., located at Basiluzzo Island. This structure has been studied through marine surveys and archaeological interpretations and is presently located at a corrected depth of 4.10 0.2 m. We explain this submergence by a cumulative effect of the relative sea level change caused by the regional glaciohydro- isostatic signal, active since the end of the last glacial maximum, and the local volcano-tectonic land subsidence. Finally, a total subsidence rate of 2.05 0.1 mm/yr 1, with a volcano-tectonic contribution of 1.43 0.1 mm/yr 1 for the last 2 ka BP, is inferred from the comparison against the latest predicted sea level curve for the Southern Tyrrhenian Sea, suggesting new evaluations of the volcanotectonic hazard for this area of the Aeolian islands.
    Beschreibung: Published
    Beschreibung: 143-150
    Beschreibung: 4V. Vulcani e ambiente
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Aeolian islands, sea level, crustal deformations ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
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    Human colonization and volcanic activity in the eastern Campania Plain (Italy) between the Eneolithic and Late Roman periods (2013)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 132-141
    Beschreibung: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.10. Storia ed archeologia applicate alle Scienze della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): 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
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    Seismic and Infrasound Signals at Mt. Etna: Modelling the North-East Crater Conduit and its Relation with the 2008-2009 Eruption Feeding System (2013)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 53-68
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): 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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  • 7
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    A two-component mantle source feeding Mt. Etna magmatism: Insights from the geochemistry of primitive magmas (2013)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-10-06
    Beschreibung: Themajor elements, trace elements and Sr and Nd isotopes of selected Etnean primitive rocks (b15 ky BP) were studied in order to characterize their mantle source. The noble-gas geochemistry of fluid inclusions in minerals fromthe same lavaswas also investigated. Themajor element compositions ofwhole rocks and minerals showed that these products are among the most primitive atMt. Etna, comprising 6.3–17.5 wt.% MgO. The variable LREE (Light Rare Earth Elements) enrichment relative to MORB (Mid-Ocean Ridge Basalt) (Lan/Ybn = 11–26), togetherwith the patterns of certain trace-element ratios (i.e., Ce/Yb versus Zr/Nb and Th/Y versus La/Yb), can be attributed to varying degrees of melting of a common mantle source. Numerical simulations performed with the MELTS program allowed the melting percentages associated with each product to be estimated. This led us to recalculate the hypothetical parental trace-element content of the Etneanmantle source, whichwas common to all of the investigated rocks. The characteristics of the Sr, Nd and He isotopes confirmed the primitive nature of the rocks,with themost-depleted and primitive lava being that ofMt. Spagnolo (SPA; 143Nd/144Nd = 0.512908 87Sr/ 86Sr = 0.703317–0.703325 and 3He/4He = 7.6 Ra), and highlighted the similarity of the mantle sources feeding the volcanic activity of Mt. Etna and the Hyblean Plateau (a region to the south of Mt. Etna and characterized by oldermagmatismthan Mt. Etna). The coupling of noble gases and trace elements suggests an origin for the investigated Etnean lavas from melting of a Hyblean-like mantle, consisting of a two-component source where a peridotitic matrix is veined by 10% pyroxenite. A variable degree of mantle contamination by crustal-like fluids, probably related to subduction, is proposed to explain the higher Sr-isotope and lowerNd-isotope values in some rocks (143Nd/144Nd up to 0.512865 and 87Sr/86Sr up to 0.703707). This process probably occurred in the source prior tomagma generation, refertilizing some portions of themantle. Accordingly, the estimated degree of melting responsible for each magma appears to be related to its 87Sr/86Sr enrichment. In contrast, the decoupling between 3He/4He and 87Sr/86Sr ratios requires the occurrence in the crustal reservoirs of further processes capable of shifting the He isotope ratio towards slightly more radiogenic values, such as magma aging or a contribution of shallow fluid. Therefore, different residence times in the Etnean reservoir and/or various rates of magma ascent could be key parameters for preserving the original He isotope marker of the Etnean mantle source.
    Beschreibung: Published
    Beschreibung: 243-258
    Beschreibung: 5V. Sorveglianza vulcanica ed emergenze
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Mt. Etna ; Hyblean Plateaux ; Primitive magma ; Mantle metasomatism ; Peridotite ; Pyroxenite ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    Probabilistic seismic hazard at Mt. Etna (Italy): The contribution of local fault activity in mid-term assessment (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2021-03-01
    Beschreibung: In this work, we tackle the problem of seismic hazard at Etna deriving from the recurrent seismogenic activity of local faults, by adopting two independent methods based on probabilistic approaches. We assess the hazard in terms of macroseismic intensity and represent the occurrence probability calculated for different exposure times both on maps and at fault scale. Seismic hazard maps obtained by applying the “site approach” through the SASHA code and a new probabilistic attenuation model, indicate the eastern flank of the volcano as the most hazardous, with expected intensity (Iexp) in 50 years (i.e. the standard exposure time adopted in the seismic regulations) ranging from degrees IX to X EMS. In shorter exposure periods (20, 10, 5 years), values of Iexp up to IX are also reached in the same area, but they are clearly determined by the earthquakes generated by the Timpe fault system. In order to quantify the contribution of local seismogenic sources to the hazard of the region, we reconstruct the seismic history of each fault and calculate with SASHA the probability that earthquakes of a given intensity may be generated in different exposure times. Results confirm the high level of hazard due to the S. Tecla, Moscarello and Fiandaca faults especially for earthquakes of moderate intensity, i.e. VI≤I0≤VII, with probabilities respectively exceeding 50% and 20% in 10 years, and 30% and 10% in 5 years. Occurrence probability of major events (I0≥VIII) at the fault scale has also been investigated by statistics on intertimes. Under stationary assumptions we obtain a probability of 6.8% in 5 years for each structure; by introducing the time-dependency (time elapsed since the last event occurred on each fault) through a BPT model, we identify the Moscarello and S. Tecla faults as the most probable sources to be activated in the next 5 years (2013–2017). This result may represent a useful indication to establish priority criteria for actions aimed at reducing seismic risk at a local scale.
    Beschreibung: Published
    Beschreibung: 158-169
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Macroseismic intensity ; Seismic history ; Occurrence probability ; Time-dependent renewal process ; Individual sources ; Seismic hazard ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    Forecasting seismic scenarios on Etna volcano (Italy) through probabilistic intensity attenuation models: A Bayesian approach (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2021-03-01
    Beschreibung: In this paper, we apply a probabilistic procedure to model the attenuation of the macroseismic intensity in the Mt. Etna region, which allows estimating probabilistic seismic scenarios. Starting from the local earthquake catalogue, we select a dataset of 47 events having epicentral intensity I0 from VI to IX–X EMS, and update the model parameters previously achieved for Italy according to the Bayesian paradigm. For each class of epicentral intensity I0, we then estimate the probability distribution of the intensity at a site conditioned on the epicentre-site distance through a binomial-beta model, under the assumption of a point seismic source and isotropic decay (circular). The mode of the distribution is taken as the expected intensity Is at that site. Since the strongest earthquakes show a preferential propagation of shaking along the fault strike and a rapid decrease in the perpendicular direction, we also consider the anisotropic decay (elliptical) of the intensity due to a linear source (finite fault). We therefore transform the plane so that the ellipse has the length of the fault rupture as maximum axis and its strike as azimuth is changed into a circle with fixed diameter; then we apply the probabilistic model obtained for the isotropic case to the modified data. The entire calculation procedure is implemented in the software PROSCEN which, given the location and the epicentral intensity (and eventually the fault parameters) of the earthquake to be simulated, generates the probabilistic seismic scenario according to the isotropic and anisotropic models of attenuation. The results can be plotted on grid maps representing (1) the intensity that can be exceeded with a fixed probability, or (2) the probability of exceeding a fixed intensity value. The first representation may also find application in seismic monitoring at Etna volcano, in order to produce real-time intensity ShakeMaps based on the instrumental parameters calculated by the automatic earthquake processing system.
    Beschreibung: Published
    Beschreibung: 149-157
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Macroseismic intensity ; Attenuation Probability distribution ; Source models ; Seismic scenario ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    BUILDING MATERIALS OF THE THEATRE OF MARCELLUS, ROME* (2012)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2021-06-22
    Beschreibung: The building materials of the Theatre of Marcellus, 44–11 BCE, reflect Roman builders’ careful selections of tuff and travertine for dimension stone and volcanic aggregates for pozzolanic concretes. The vitric–lithic–crystal Tufo Lionato tuff dimension stone contains a high proportion of lava lithic fragments, which increase its compressive strength and decrease water sorption, enhancing durability. Sophisticated installations of travertine dimension stone reinforce the tuff masonry, which is integrated with durable concrete walls and barrel vaults. The pozzolanic mortars of the concretes contain harenae fossiciae mainly from the intermediate alteration facies of the mid-Pleistocene, scoriaceous Pozzolane Rosse pyroclastic flow. They have pervasive interpenetrating pozzolanic cements, including strätlingite, similar to highquality, imperial era mortars. Concrete walls are faced with refined Tufo Lionato opus reticulatum and tufelli, and opus testaceum of fired, greyish-yellow brick. The exploratory concrete masonry, which includes some of the earliest examples of brick facings and strätlingite cements in Rome, and the integration of these materials in complex architectural elements and internal spaces, reflect the highly skilled workmanship, rigorous work-site management and technical supervision of Roman builders trained in republican era methods and materials.
    Beschreibung: Published
    Beschreibung: 728–742
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): VOLCANIC TUFF MASONRY ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
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    The Alban Hills and Monti Sabatini volcanic products used in ancient Roman masonry (Italy): An integrated stratigraphic, archaeological, environmental and geochemical approach (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2021-06-22
    Beschreibung: The rocks of Alban Hills and Monti Sabatini volcanoes (Central Italy) and their associated epiclastic deposits have been extensively used as building material in ancient Rome from about VIIIth century BCE to IVth century CE. However, the identification of the source areas of these rocks is difficult due to the lack of an integrated stratigraphic and geochemical analysis of the relationships between the two volcanic districts, and to the alteration affecting the primary products as consequence of weathering and pedogenetic processes. Here, a comprehensive, upgraded stratigraphic and geochronological review of the two volcanic districts, corroborated by new geochronological data for several eruptive units and altered deposits is presented, coupled to a complete geochemical background, achieved by means of newly determined major and trace element analyses for all the main eruptive units. A study of the alteration processes of the primary products is also presented, and the age of the main weathering and pedogenetic phases, associated to Quaternary climatic changes, are also investigated. The results are integrated with those from literature in order to construct discriminant diagrams based on selected trace elements, and allow us to characterize the primary and altered volcanic deposits in the Rome area, distinguish products of different volcanic districts, discuss the effects of different weathering processes on the mobility of some elements, and provide a reference frame for the provenance of the volcanic materials employed in ancient Roman masonry. The interdisciplinary data set and results presented here provide groundwork for volcanological, climate, pedological and archaeological provenance studies.
    Beschreibung: Published
    Beschreibung: 115–136
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Quaternary volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    Generation of pyroclastic flows by explosive interaction of lava flows with ice/water-saturated substrate (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2021-01-27
    Beschreibung: We describe a new type of secondary rootless phreatomagmatic explosions observed at active lava flows at volcanoes Klyuchevskoy (Russia) and Etna (Italy). The explosions occurred at considerable (up to 5 km) distances from primary volcanic vents, generally at steep (15–35°) slopes, and in places where incandescent basaltic or basaltic-andesitic lava propagated over ice/water-saturated substrate. The explosions produced high (up to 7 km) vertical ash/steam-laden clouds as well as pyroclastic flows that traveled up to 2 km downslope. Individual lobes of the pyroclastic flow deposits were up to 2 m thick, had steep lateral margins, and were composed of angular to subrounded bomb-size clasts in a poorly sorted ash–lapilli matrix. Character of the juvenile rock clasts in the pyroclastic flows (poorly vesiculated with chilled and fractured cauliflower outer surfaces) indicated their origin by explosive fragmentation of lava due to contact with external water. Non-juvenile rocks derived from the substrate of the lava flows comprised up to 75% in some of the pyroclastic flow deposits. We suggest a model where gradual heating of a water-saturated substrate under the advancing lava flow elevates pore pressure and thus reduces basal friction (in the case of frozen substrate water is initially formed by thawing of the substrate along the contact with lava). On steep slope this leads to gravitational instability and sliding of a part of the active lava flow and water-saturated substrate. The sliding lava and substrate disintegrate and intermix, triggering explosive “fuel–coolant” type interaction that produces large volume of fine-grained clastic material. Relatively cold steam-laden cloud of the phreatomagmatic explosion has limited capacity to transport upward the produced clastic material, thus part of it descends downslope in the form of pyroclastic flow. Similar explosive events were described for active lava flows of Llaima (Chile), Pavlof (Alaska), and Hekla (Iceland) indicating that this type of explosions and related hazard is common at snow/ice-clad volcanoes and sometimes happens also on fluid-saturated hydrothermally altered slopes.
    Beschreibung: Published
    Beschreibung: 60–72
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): lava flow; pyroclastic flow; secondary explosion; phreatomagmatic explosion; Klyuchevskoy; Etna ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
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    Ground deformation at calderas driven by fluid injection: modelling unrest episodes at Campi Flegrei (Italy) (2012)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: Campi Flegrei collapse caldera (Italy) is a high-risk volcanic area located close to Naples and includes part of the densely populated city. This area is characterised by large up and down ground displacements. The last large uplift episode caused 3.5 m of cumulative vertical displacement at the centre of the town of Pozzuoli, during the period 1969–1984. Up and down ground movements in this area often occur without intercurring eruptions and are similar to what is observed at other calderas worldwide. Here, however, they appear more evident and amplified. Understanding the mechanism of such movements is crucial for hazard assessment and eruption forecast, mainly due to this densely populated area. This paper presents a detailed model for ground displacements due to deep fluid injection in shallower layers. Such a model explains in a natural way the occurrence of uplift and subsidence without eruptions. We show that it is possible to fit observed ground deformation in this area with a thermofluid dynamical model. The model obtained is also consistent with other observations like microgravity changes, changes in CO2 flux, etc. Here, we suggest that significant uplift and subsidence at calderas can be due to effects of deep fluid injections other than magma. At Campi Flegrei, however, a partial magmatic contribution at the origin of the observed episodes cannot be excluded.
    Beschreibung: Published
    Beschreibung: 833–847
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Numerical approximations and analysis; Hydrothermal systems; Explosive volcanism; Calderas ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
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    Quaternary still-stand landforms and relations with flank instability events of the Palinuro Bank (southeastern Tyrrhenian Sea) (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: A high-resolution morphological and geological inspection was carried out on the Palinuro Bank (39 300N, 14 480E), a volcanic complex made by several, coalescent volcanic features located on the Cam- panian continental slope (Eastern Tyrrhenian Sea, Italy). A shallow ( 84 m asl) volcanic edifice, char- acterized by a flat top modelled surface, is present on its central sector. The use of a very high-resolution Digital Terrain Model allowed recognition of the presence of relict morphologies (perhaps notches/inner margins) related to the past sea-level still-stands. Three depth levels of paleo-shorelines markers are located at 90 m, 100 m, and 123 m, respectively. In addiction, the truncated shape of the cone itself, located between 84 m and 130 m, could be interpreted as a tilted marine terrace. Breaks in slope produced by terrace landforms caused oversteepening that could have triggered lateral collapses both on the northern and southern flanks of the Bank, as suggested by the presence of steep slopes (25e40 ) and indicated by acoustic facies on chirp high-resolution mono-channel seismic profiles. The results allow further hypotheses on vertical displacement between the western sector of the Palinuro Bank, where caldera shapes are present, and the central sector, made by shallower volcanic cones. These two sectors also differ in terms of magnetic properties.
    Beschreibung: Published
    Beschreibung: 228-237
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Palinuro Bank ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
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    A pilot GIS database of active faults of Mt. Etna (Sicily): A tool for integrated hazard evaluation (2012)
    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.
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 170-186
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: 5.5. TTC - Sistema Informativo Territoriale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 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
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
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    Fluorine adsorption by volcanic soils at Mt. Etna, Italy (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: Fluorine adsorption experiments were performed on 28 samples of the first 5 cm of topsoil collected on the flanks of Mt. Etna. The soil samples were equilibrated with F-rich rainwater (3.25 mg/L) at a soil/water weight ratio of 1/25. Aliquots of the supernatant were collected after 1, 7, 72, 720 and 5640 h and analysed for F content. The soil samples could be subdivided into three groups based on their F-adsorption behaviours after 1 h and at the end of the experiment: (1) negative adsorption (F released from the soil to the solution) after 1 h and negative or moderately positive adsorption at the end, (2) from negative after 1 h to strongly positive adsorption at the end, and (3) always strong positive adsorption. The adsorption capacity of the soils was positively correlated with the soil pH, the contents of finer granulometric fractions (clay and silt) and the weathering stage (as quantified by the chemical alteration index). The most F adsorbing soils are found at the periphery of the volcano where aquifers are more vulnerable to contamination due to the shallower depth of the water table. This study further evidences the importance of the Etnean soils in protecting groundwater from an excessive magmatic F input.
    Beschreibung: Published
    Beschreibung: 1179–1188
    Beschreibung: 4.4. Scenari e mitigazione del rischio ambientale
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): volcanic soils ; fluoride adsorption ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.08. Risk::05.08.01. Environmental risk
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  • 17
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    Magma-ascent processes during 2005–2009 at Mt Etna inferred by soil CO2 emissions in peripheral areas of the volcano (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 218-227
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 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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  • 18
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    A forward test for interaction between remote earthquakes and volcanic eruptions: the case of Sumatra (June 2000) and Denali (November 2002) earthquakes (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We propose a formal procedure to validate the hypothesis of a causal relationship between great tectonic earthquakes and volcanic eruptions through a forward statistical test. This approach allows such a hypothesis to be evaluated in an objective way, ruling out any possible unconscious overfitting of the past data. The procedure consists of two steps: (a) the computation of the stress perturbation in a volcanic area due to some selected seismic event, by means of a spherical, layered, viscoelastic and self- gravitating earth model; and (b) the application of a statistical test to check the differences in the spatio-temporal distribution of eruptions before and after the earthquake, weighting each eruption with the stress perturbation induced at the volcano at the time of the eruption. Finally, for the sake of example, we apply the method to the case of the recent Engano earthquake in Sumatra (June 2000) and the Denali earthquake in Alaska (November 2002).
    Beschreibung: Published
    Beschreibung: 383 – 395
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): earthquake–volcano interaction ; post-seismic stress perturbation ; forward test ; Engano earthquake ; Denali earthquake ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
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    Brittle creep in basalt and its application to time-dependent volcano deformation (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: Time-dependent brittle deformation is a fundamental and pervasive process operating in the Earth's upper crust. Its characterization is a pre-requisite to understanding and unraveling the complexities of crustal evolution and dynamics. The preferential chemical interaction between pore fluids and strained atomic bonds at crack tips, a mechanism known as stress corrosion, allows rock to fail under a constant stress that is well below its short-term strength over an extended period of time; a process known as brittle creep. Here we present the first experimental measurements of brittle creep in a basic igneous rock (a basalt from Mt. Etna volcano) under triaxial stress conditions. Results from conventional creep experiments show that creep strain rates are highly dependent on the level of applied stress (and can be equally well fit by a power law or an exponential law); with a 20% increase in stress producing close to three orders of magnitude increase in creep strain rate. Results from stress-stepping creep experiments show that creep strain rates are also influenced by the imposed effective confining pressure. We show that only part of this change can be attributed to the purely mechanical influence of an increase in effective pressure, with the remainder interpreted as due to a reduction in stress corrosion reactions; the result of a reduction in crack aperture that restricts the rate of transport of reactive species to crack tips. Overall, our results also suggest that a critical level of crack damage is required before the deformation starts to accelerate to failure, regardless of the level of applied stress and the time taken to reach this point. The experimental results are discussed in terms of microstructural observations and fits to a macroscopic creep law, and compared with the observed deformation history at Mt. Etna volcano.
    Beschreibung: Published
    Beschreibung: 71–82
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): stress corrosion ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
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    An overview of experimental models to understand a complex volcanic instability: Application to Mount Etna, Italy (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Volcanic edifices are often unable to support their own load, triggering the instability of their flanks. Many analogue models have been aimed, especially in the last decade, at understanding the processes leading to volcano flank instability; general behaviors were defined and the experimental results were compared to nature. However, available data at well-studied unstable volcanoes may allow a deeper understanding of the specific processes leading to instability, providing insights also at the local scale. Etna (Italy) constitutes a suitable example for such a possibility, because of its well-monitored flank instability, for which different triggering factors have been proposed in the last two decades. Among these factors, recent InSAR data highlight the role played by magmatic intrusions and a weak basement, under a differential unbuttressing at the volcano base. This study considers original and recently published experimental data to test these factors possibly responsible for flank instability, with the final aim to better understand and summarize the conditions leading to flank instability at Etna. In particular, we simulate the following processes: a) the longterm activity of a lithospheric boundary, as the Malta Escarpment, separating the Ionian oceanic lithosphere from the continental Sicilian lithosphere, below the most unstable east flank of the volcano; b) spreading due to a weak basement, with different boundary conditions; c) the pressurization of a magmatic reservoir, as that active during the 1994–2001 inflation period; d) dike emplacement, as observed during the major 2001 and 2002–2003 eruptions. The experimental results suggest that: 1) the long-term activity of a lithospheric tectonic boundary may create a topographic slope which provides a differential buttressing at the volcano base, a preparing factor to drive longer-term (〉105 years) instability on the east flank of the volcano; 2) volcano spreading (b104 years) has limited effect on flank instability at Etna; 3) magmatic intrusions (b101 years), both in the form of Mogi-like sources or dikes, provide the most important conditions to trigger flank instability on the shorter-term.
    Beschreibung: Thisworkwas partially funded by INGV and the Italian DPC (DPC-INGV project V4 “Flank”).
    Beschreibung: Published
    Beschreibung: 98-111
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): volcano instability ; analogue modeling ; Etna ; unbuttressing ; 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::04.07. 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::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 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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  • 21
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    Intrusive mechanism of the 2008–2009 Mt. Etna eruption: Constraints by tomographic images and stress tensor analysis (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Since January 2008, several geophysical parameters have evidenced a recharging phase at Mt. Etna volcano culminating with an effusive eruption that began on May 13, 2008. Seismic activity recorded at Mt. Etna from January 2007 to May 2008 was analyzed in order to provide seismological constraints to the volcano dynamics leading to the eruption. A total of 336 selected earthquakes, withML≥1.5, were used as data source for this study. Specifically, we calculated 3D velocity and attenuation tomography, including a 3D relocation of the events, and we computed 53 selected fault plane solutions (FPSs) that were used for stress tensor inversion. The most important result obtained from the joint analysis of VP, VP/VS and P-wave attenuation is an anomalous zone with normal to high VP (values between 3.5 and 4.5 km/s) and low VP/VS (values≤1.64), which partially overlaps with a low QP (values≤50) volume located along a NS trending channel beneath the central crater. This can be interpreted as a shallow volume characterized by high temperature where the magma is located with the presence of supercritical fluids. The analysis of seismic stress tensor evidenced an extensional regime in the depth range 3–13 km with a vertically oriented σ1. This finding may suggest an extensional stress regime, probably related to the kinematic response of the volcanic edifice to both a deep magmatic intrusion and a condition of decreased regional compressive stress facilitated by sliding processes of the eastern flank of the volcano.
    Beschreibung: Published
    Beschreibung: 50–63
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Mt. Etna ; Volcanic eruptions ; Stress Tensor ; Velocity tomography ; Attenuation tomography ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 22
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    Hazard assessment at Mount Etna using a hybrid lava flow inundation model and satellite-based land classification (2012)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Using a lava flow emplacement model and a satellite-based land cover classification, we produce a map to allow assessment of the type and quantity of natural, agricultural and urban land cover at risk from lava flow invasion. The first step is to produce lava effusion rate contours, i.e., lines linking distances down a volcano’s flank that a lava flow will likely extend if fed at a given effusion rate from a predetermined vent zone. This involves first identifying a vent mask and then running a downhill flow path model from the edge of every pixel around the vent mask perimeter to the edge of the DEM. To do this, we run a stochastic model whereby the flow path is projected 1,000 times from every pixel around the vent mask perimeter with random noise being added to the DEM with each run so that a slightly different flow path is generated with each run. The FLOWGO lava flow model is then run down each path, at a series of effusion rates, to determine likely run-out distance for channel-fed flow extending down each path. These results are used to plot effusion rate contours. Finally, effusion rate contours are projected onto a land classification map (produced from an ASTER image of Etna) to assess the type and amount of each land cover class falling within each contour. The resulting maps are designed to provide a quick look-up capability to assess the type of land at risk from lava extending from any location at a range of likely effusion rates. For our first (2,000 m) vent zone case used for Etna, we find a total of area of ~680 km2 is at risk from flows fed at 40 m3 s−1, of which ~6 km2 is urban, ~150 km2 is agriculture and ~270 km2 is grass/woodland. The model can also be run for specific cases, where we find that Etna’s 1669 vent location, if active today, would likely inundate almost 11 km2 of urban land, as well as 15.6 km2 of agricultural land, including 9.5 km2 of olive groves and 5.2 km2 of vineyards and fruit/nut orchards.
    Beschreibung: Published
    Beschreibung: 1001-1027
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Lava flow ; Risk ; FLOWGO ; ASTER image ; Land classification ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 23
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    Geochemical evidence for mixing between fluids exsolved at different depths in the magmatic system of Mt Etna (Italy) (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 380-394
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): 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
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  • 24
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    Evidence for a recent change in the shallow plumbing system of Mt. Etna (Italy): Gas geochemistry and structural data during 2001–2005 (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: 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.
    Beschreibung: This work was funded by grants from the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and from the Dipartimento per la Protezione Civile (Italy).
    Beschreibung: Published
    Beschreibung: 90-97
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 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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  • 25
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    Continental margin large-scale instability controlling the flank sliding of Etna volcano (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: Etna volcano is affected by a downward sliding of its eastern flank, as rapid as a few cm/year, whose nature is highly debated. Recently collected marine geological and geophysical data allows a detailed image of the morphostructural setting of the continental margin facing the volcano. Here, a large bulge offsets the margin that is deeply affected by widespread semicircular steps, interpreted as evidence of large-scale gravitational instability. Such features permeate the whole margin and extend inshore to the volcano sector where the larger ground deformations are measured. Both submarine instability and subaerial flank sliding are bounded by two regional tectonic lineaments interpreted as weakness lines. These cross the coastline to accommodate the basinward movement of this large sector of the continental margin topped by the Etna volcanic pile. The new data allows re-interpreting the tectonic setting of the coastal belt and proposing a novel structural model, highlighting the active role of the continental margin instability to drive the seaward sliding of the volcano's eastern flank. This model may suggest why a very active basaltic volcano has so unusually developed in front of an active thrust belt.
    Beschreibung: Published
    Beschreibung: 57–64
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): volcano sliding ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 26
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    Unbekannt
    Morphometry of scoria cones, and their relation to geodynamic setting: A DEM-based analysis (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: The morphometry of a great number of scoria cones, belonging to volcanic fields of various geodynamic settings, has been measured and analyzed, addressing the question whether there is a relation between the prevalent cone shape in a given field and the geodynamic setting of the field itself. Morphometric analysis was carried out on freely downloadable digital elevation models (DEMs). The accuracy of the used DEMs and the associated error in scoria cone morphometry were determined by cross-comparing high-resolution LIDAR-derived DEMs, USGS NED, TINITALY DEM and ASTER GDEM. The 10-m TINITALY/01 and USGS NED DEMs are proven to be suitable for scoria cone morphometry, whereas ASTER GDEM can be used reliably for cones with volume greater than 30 × 106 m3. According to a detailed morphometry of all scoria cones, we propose that the cones related to subductional setting show relatively higher values of Hco/Wco and lower values of Wcr/Wco than the cones related to extensional setting. The detected differences can be imputable to peculiar eruption dynamics resulting in slight but systematic changes in shape, and differences in lithological and sedimentological characteristics that govern post-eruptive erosion. To constrain the pathway of scoria cone erosion, the detected morphometric changes were also interpreted using a simple linear degradation model. Utilizing the obtained simulation results, the inferred initial cone base, and the age of scoria cones, we calculated a diffusion coefficient (K) for several dated cones, which are related to the prevalent climate. Our results, despite the high error associated, allow to assess the median K for all volcanic fields. Due to the complexity of the factors behind, it is not easy to understand if the prevalent shape characterizing a certain volcanic field is due mainly to sin-eruptive or post-eruptive mechanisms; however, our distinction between the two main geodynamic settings may be the first step to decipher these factors.
    Beschreibung: Published
    Beschreibung: 56-72
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Scoria cone ; Digital elevation models (DEMs) ; Morphometry ; Volcanic field ; Cone degradation simulation ; Geodynamic setting ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 27
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    Electrical conductivity, ground displacement, gravity changes, and gas flow at Solfatara crater (Campi Flegrei caldera, Italy): Results from numerical modeling (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: Hydrothermal fluid circulation may cause measurable gravity changes and ground deformation. We extend our previous studies and increase the number of observable parameters to include gas temperature, the rate of diffuse degassing, the extent of the degassing area, and electrical conductivity. We have carried out simulations using TOUGH2/EOS2 of a large scale hydrothermal system, then we have calculated observables arising from changes in hydrothermal fluid circulation. Our results show that fluids affect many observable parameters generating detectable signals. However, a more detailed description of the shallow subsurface is necessary to properly calculate electrical conductivity. Studies at Solfatara volcano (Campi Flegrei caldera, Italy) highlight the presence of an unsaturated layer at depth and allow to determine the position of the water table. Then, we present results from a new, small scale simulation, focused on the crater, and carried out with a new, refined meshgrid taking into account the real topography. Aim of the work is to calculate a detailed electrical conductivity map and reproduce the main features of the Solfatara crater.
    Beschreibung: Published
    Beschreibung: 93–105
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Electrical conductivity ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
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    Evidence for Late Pleistocene uplift at the Somma-Vesuvius apron near Pompeii (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: Detailed stratigraphic and micropalaeontological analyses of samples from boreholes at the Somma-Vesuvius apron, between Pompeii and the sea, allowed reconstruction of Late Quaternary palaeoenvironmental evolution of the Sarno coastal plain. In all, 116 samples were recovered from seven boreholes drilled from 2–10 m a.s.l. to 16.5–26 m b.s.l. Microfossil assemblages, with special regard to benthic foraminifers and ostracods, were used to reconstruct the depositional palaeoenvironment. Fossil remains show that all the pre-79 AD fossiliferous sediments from 2 to − 24 m a.s.l. were deposited in shallow marine waters for a long time despite an appreciable sea level rise. The data indicate alternation of both shallow marine and subaerial conditions during the last ~ 15 kyr, evidencing ground uplift of the area of about 75 m at a rate of ~ 5 mm/year. Marine sediment accumulation (~ 6 m/kyr) and tectonic uplift long offset the sea level rise, and as a consequence, submerged areas remained the same as well.
    Beschreibung: Published
    Beschreibung: 211–227
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): ground uplift; Somma-Vesuvius; Pleistocene; Palaeoecology; benthic foraminifers; ostracods ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
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    Influence of thermal and mechanical cracks on permeability and elastic wave velocities in a basalt from Mt. Etna volcano subjected to elevated pressure (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: 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, from 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.
    Beschreibung: Published
    Beschreibung: 60–74
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Elastic wave velocity ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 30
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    Source and mobility of minor and trace elements in a volcanic aquifer system: Mt. Vulture (southern Italy) (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2022-03-02
    Beschreibung: In this paper we provide a geochemical investigation on 34 groundwater samples in the Mt. Vulture volcanic aquifer representing one of the most important groundwater resources of the southern Italy pumped for drinking and irrigation supply. The present study includes the first data on the abundance and mobility of minor and trace elements and the thermodynamic considerations on water–rock interaction processes in order to evaluate the conditions of alkali basalt weathering by waters enriched in magma-derived CO2. The results highlight the occurrence of two hydrofacies: bicarbonate alkaline-earth and alkaline waters deriving from low-temperature leaching of volcanic rocks of Mt. Vulture, and bicarbonate-sulfate-alkaline waters (high-salinity waters) related to prolonged water circulation in alkali and feldspathoids-rich pyroclastic layers interbedded with clay deposits. The Al-normalized relative mobility (RM) of metals in Vulture's aquifer varies over a wide range (10− 1 〈 RM 〈 104), confirming that the basalt weathering is not a congruent and isochemical process. Chemical equilibrium studies show that the bicarbonate alkaline-earth and alkaline waters, having a short interaction with silicate minerals, plot very close to the kaolinite–smectite stability boundary, whereas the high-salinity waters fall in the stability field of smectite and muscovite because of prolonged interaction with alkali and feldspathoids-rich pyroclastic layers. Overall, for the bicarbonate alkaline-earth and alkaline waters, the release of toxic metals in solutions is related to the spatial variation of host-rock geochemistry, the high-salinity waters, collected near urban areas, show values higher than legal limits for Ni and As, likely as a consequence of anthropogenic contribution.
    Beschreibung: Published
    Beschreibung: 233-244
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): volcanic aquifer system ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
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    Tephrostratigraphy and glass compositions of post-15 kyr Campi Flegrei eruptions: implications for eruption history and chronostratigraphic markers (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2021-12-06
    Beschreibung: Volcanic ash (tephra) erupted from the frequently active Campi Flegrei volcano forms layers in many palaeoenvironmental archives across Italy and the Mediterranean. Proximal deposits of 50 of the post-15 ka eruptions have been thoroughly sampled and analysed to produce a complete database of glass compositions (〉1900 analyses) to aid identification of these units. The deposits of individual eruptions are compositionally diverse and this variability is often greater than that observed between different units. Many of the tephra units do not have a unique glass chemistry, with compositionally similar tephra often erupted over long periods of time (1000s years). Thus, glass chemistry alone is not enough to robustly correlate most of the tephra from Campi Flegrei, especially in the last 10 kyrs. In order to reliably correlate the eruption units it is important to take into account the stratigraphy, chronology, magnitude, and dispersal of the eruptions, which has been collated to aid identification. An updated chronology is also presented, which was constrained using Bayesian analysis (OxCal) of published radiocarbon dates and 40Ar/39Ar ages. All the data presented can be employed to help correlate post-15 ka tephra units preserved in archaeological and Holocene palaeoenvironmental archives. The new database of proximal glass compositions has been used to correlate proximal volcanic deposits through to distal tephra layers in the Lago di Monticchio record ( [Wulf et al., 2004] and [Wulf et al., 2008]) and these correlations provide information on eruption stratigraphy and the tempo of volcanism at Campi Flegrei.
    Beschreibung: Published
    Beschreibung: 3638–3660
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Tephrochronology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
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    PROVENANCING OF LIGHTWEIGHT VOLCANIC STONES USED IN ANCIENT ROMAN CONCRETE VAULTING: EVIDENCE FROM ROME (2012)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2021-12-15
    Beschreibung: Some of the most structurally innovative concrete vaults built in imperial Rome employed lightweight volcanic rocks to reduce the lateral thrust on the supporting walls, the most famous being the Pantheon. Roman concrete (opus caementicium) was made up of mortar binding together pieces of large aggregate (caementa) usually ranging from 10 to 20 cm long, which were hand laid in the mortar (as opposed to being poured as is typical in modern concrete), so that it resembles mortared rubble. A key aspect of the development of large-scale concrete vaulting was the ability to regulate the weight of the ingredients in order to reduce the weight of the vaults and to control the forces within the structure. The volcanic environment along the west coast of Italy provided numerous stones of different weights and physical properties from which the builders could choose (Fig. 1), including pumice and scoria, which were the most common choices for the lightweight caementa of the most innovative vaulted structures. Because these materials were produced by many of the Italian volcanoes, our goal was to establish the provenance of those used in vaults in Rome in order to understand better the supply network. We first used thin sections to narrow the potential sources and then we submitted selected samples to X-ray fluorescence
    Beschreibung: Published
    Beschreibung: 707-727
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): concrete vault ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
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    Ultra-distal tephra deposits from super-eruptions: Examples from Toba, Indonesia and Taupo Volcanic Zone, New Zealand (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2021-12-06
    Beschreibung: Voluminous rhyolitic eruptions from Toba, Indonesia, and Taupo Volcanic Zone (TVZ), New Zealand have dispersed volcanic ash over vast areas in the late Quaternary. The w74 ka Youngest Toba Tuff (YTT) eruption deposited ash over the Bay of Bengal and the Indian subcontinent to the west. The w340 ka Whakamaru eruption (TVZ) deposited the widespread Rangitawa Tephra, dominantly to the southeast (in addition to occurrences northwest of vent), extending across the landmass of New Zealand, and the South Pacific Ocean and Tasman Sea with distal terrestrial exposures on the Chatham Islands. These super-eruptions involved w2500 km3 and w1500 km3 of magma (dense-rock equivalent; DRE), respectively. Ultra-distal terrestrial exposures of YTT at two localities in India, Middle Son Valley, Madhya Pradesh, and Jurreru River Valley, Andhra Pradesh, at distances of 〉2000 km from the source caldera, show a basal ‘primary’ ashfall unit w4 cm thick, although deposits containing reworked ash are up to w3 m in total thickness. Exposures of Rangitawa Tephra on the Chatham Islands, 〉900 km from the source caldera, are w15e30 cm thick. At more proximal localities (w200 km from source), Rangitawa Tephra is w55e70 cm thick and characterized by a crystal-rich basal layer and normal grading. Both distal tephra deposits are characterized by very-fine ash (with high PM10 fractions) and are crystal-poor. Glass chemistry, stratigraphy and grain-size data for these distal tephra deposits are presented with comparisons of their correlation, dispersal and preservation. Using field observations, ash transport and deposition were modeled for both eruptions using a semi-analytical model (HAZMAP), with assumptions concerning average wind direction and strength during eruption, column shape and vent size. Model outputs provide new insights into eruption dynamics and better estimates of eruption volumes associated with tephra fallout. Modeling based on observed YTT distal tephra thicknesses indicate a relatively low (〈40 km high), very turbulent eruption column, consistent with deposition from a co-ignimbrite cloud extending over a broad region. Similarly, the Whakamaru eruption was modeled as producing a predominantly Plinian column (w45 km high), with dispersal to the southeast by strong prevailing winds. Significant ash fallout of the main dispersal direction, to the northwest of source, cannot be replicated in this modeling. The widespread dispersal of large volumes of fine ash from both eruptions may have had global environmental consequences, acutely affecting areas up to thousands of kilometers from vent.
    Beschreibung: Published
    Beschreibung: 54–79
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Toba eruption ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 34
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    Large-eddy simulation of pyroclastic density currents (2011)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We investigate the dynamics of turbulent pyroclastic density currents (PDCs) by adopting a 3D, Eulerian-Eulerian multiphase flow model, in which solid particles are treated as a continuum and the grain-size distribution is simplified by assuming two particulate phases. The turbulent sub-grid stress of the gas phase is modelled within the framework of Large-Eddy Simulation (LES) by means of a eddy-viscosity model together with a wall closure. Despite the significant numerical diffusion associated to the upwind method adopted for the Finite-Volume discretization, numerical simulations demonstrate the need of adopting a Sub-Grid Scale (SGS) model, while revealing the complex interplay between the grid and the SGS filter sizes. We also analyse the relationship between the averaged flow dynamic pressure and the action exerted by the PDC on a cubic obstacle, to evaluate the impact of a PDC on a building. Numerical results suggest that the average flow dynamic pressure can be used as a proxy for the force per unit surface acting on the building envelope (Fig. 5), even for such steeply stratified flows. However, it is not possible to express such proportionality as a constant coefficient such as the drag coefficient in a steady-state current. The present results indeed indicate that the large epistemic and aleatory uncertainty on initial and boundary conditions has an impact on the numerical predictions which is comparable to that of grid resolution.
    Beschreibung: Published
    Beschreibung: 161-170
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: open
    Schlagwort(e): Large-Eddy Simulation ; pyroclastic density currents ; numerical simulation ; multiphase flows ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book chapter
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  • 35
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    Towards an automatic monitoring system of infrasonic events at Mt. Etna: strategies for source location and modelling (2010)
    Springer
    Details
    Publikationsdatum: 2020-11-16
    Beschreibung: Active volcanoes characterized by open conduit conditions generate sonic and infrasonic signals, whose investigation provides useful information for both monitoring purposes and studying the dynamics of explosive processes. In this work, we discuss the automatic procedures implemented for a real-time application to the data acquired by a permanent network of five infrasound stations running at Mt. Etna volcano. The infrasound signals at Mt. Etna consist in amplitude transients, called infrasound events. The adopted procedure uses a multi-algorithm approach for event detection, counting, characterization and location. It is designed for an efficient and accurate processing of infrasound records provided by single-site and array stations. Moreover, the source mechanism of these events can be investigated off-line or in near real-time by using three different models: i) Strombolian bubble; ii) resonating conduit and iii) Helmholtz resonator. The infrasound waveforms allow us to choose the most suitable model, to get quantitative information about the source and to follow the time evolution of the source parameters.
    Beschreibung: Published
    Beschreibung: 1215–1231
    Beschreibung: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): infrasound ; monitoring system ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    facet.materialart.
    Unbekannt
    Large-eddy simulation of pyroclastic density currents (2010)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We investigate the dynamics of turbulent pyroclastic density currents (PDCs) by adopting a 3D, Eulerian-Eulerian multiphase flow model, in which solid particles are treated as a continuum and the grain-size distribution is simplified by assuming two particulate phases. The turbulent sub-grid stress of the gas phase is modelled within the framework of Large-Eddy Simulation (LES) by means of a eddy-viscosity model together with a wall closure. Despite the significant numerical diffusion associated to the upwind method adopted for the Finite-Volume discretization, numerical simulations demonstrate the need of adopting a Sub-Grid Scale (SGS) model, while revealing the complex interplay between the grid and the SGS filter sizes. We also analyse the relationship between the averaged flow dynamic pressure and the action exerted by the PDC on a cubic obstacle, to evaluate the impact of a PDC on a building. Numerical results suggest that the average flow dynamic pressure can be used as a proxy for the force per unit surface acting on the building envelope (Fig. 5), even for such steeply stratified flows. However, it is not possible to express such roportionality as a constant coefficient such as the drag coefficient in a steady-state current. The present results indeed indicate that the large epistemic and aleatory uncertainty on initial and boundary conditions has an impact on the numerical redictions which is comparable to that of grid resolution.
    Beschreibung: Unpublished
    Beschreibung: (10)
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: open
    Schlagwort(e): Large-Eddy Simulation ; pyroclastic density currents ; numerical simulation ; multiphase flows ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book chapter
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  • 37
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    Degassing behavior of Mt. Etna volcano (Italy) during 2007-2008, inferred (2010)
    EGU
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Studies on volcanic degassing have recently shown the important role of volatile release from active volcanoes in understanding magmatic processes prior to eruptions. Here we present and discuss the evolution of magmatic degassing that preceded and accompanied the 2008 Mt. Etna eruption. We tracked the ascent of magma bodies by high-temporal resolution measurements of SO2 emission rates and discrete sampling of SO2/HCl and SO2/HF molar ratios in the crater plume, as well as by periodic measurement of soil CO2 emission rates. Our data suggest that the first signs of upward migration of gas-rich magma before the 2008 eruption were observed in June 2007, indicated by a strong increase in soil CO2 efflux followed by a slow declining trend in SO2 flux and halogens. This degassing behavior preceded the mid-August 2007 summit activity culminated with the September 4th paroxysmal event. Five months later, a new increase in both soil CO2 and SO2 emission rates occurred before the November 23rd paroxysm, to drop down in late December. In the following months, geochemical parameters showed high variability, characterized by isolated sudden increases occurred in early December 2007 and late March 2008. In early May soil CO2, SO2 emission rates and S/Cl molar ratio gradually increased. Crater degassing peaked on May 13th marking the onset of the eruption. Eruptive activity was accompanied by a general steady-state of SO2 flux characterized by two main degassing cycles. These cycles preceded explosive activity at the eruptive vents, indicating terminal new-arrival of deep gas-rich magma bodies in the shallow plumbing system of Mt Etna. Conversely, halogens described a slight increasing trend till the end of 2008. These observations suggest an impulsive syn-eruptive dynamics of magma transfer from depth to the surface. Differently from the SO2 emission rates, the S/Cl ratio and the soil CO2 efflux values showed an increasing trend from mid-April to mid-July 2008, indicating steady-increasing input of deeper, gas-rich magma. Since August, geochemical parameters decreased, suggesting that new magma has not arrived from depth. According to our interpretation, both the CO2 efflux and the S/Cl ratio increases observed in early November may indicate a new input of fresh magma form depth. Finally, the estimated volume of degassing magma showed substantial equilibrium between degassed and erupted magma suggesting an “eruptive” steady-state of the volcano.
    Beschreibung: INGV, Sezione di Catania; INGV, Sezione di Pisa; University of Cambridge, Cambridge, UK
    Beschreibung: Published
    Beschreibung: Vienna, Austria
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: open
    Schlagwort(e): Mt. Etna ; plume gases ; soil CO2 ; eruption ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
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    Coupling high-frequency measurement of 222Rn, 220Rn in soil gases with (2010)
    EGU
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Concurrent measurement of soil radon, soil thoron and soil CO2 efflux is based on the method developed by Giammanco et al. (Geochem. Geophys. Geosys., 8(10), Q 10001, doi:10.1029/2007GC001644, 2007). An empirical relationship links the 222Rn/220Rn ratio to the CO2 efflux: deep sources of gas are characterized by high 222Rn activity and high CO2 efflux, whereas shallow sources are indicated by high 220Rn activity and relatively low CO2 efflux. This relationship is more constraining on the type and depth of the gas source than using the 222Rn/220Rn ratio alone.We studied the temporal variation of the ratio between CO2 efflux and (222Rn/220Rn), that we define as a Soil Gas Disequilibrium Index (SGDI). Since June 2006, periodical measurements of the SGDI were carried out in ten sites located on the flanks of Mt. Etna, with sampling frequency of about ten days. Remarkable variations in this parameter were recorded during the period 2006-2008 likely associated with changes in the activity level of Mt. Etna. In particular, one of the sites located in the area called Primoti (on the lower east flank of the volcano) has shown significant anomalous changes of the SGDI in time, possibly correlated with the eruptive/tectonic activity. For this reason, in this site we set up an automatic monitoring station made of a Radon/Thoron monitor (model RTM 2100, SARAD GmbH, Germany) coupled with a soil CO2 efflux station (model ACE, ADC BioScientific Ltd., UK). The sampling frequency was set at 30 minutes, in order to allow for a sufficient decay equilibration in the radon isotopes. Air temperature and barometric pressure were recorded as well, with the same sampling rate as for the soil gases. The site chosen for testing the monitoring station is located on the east flank of Mt. Etna at an altitude of about 520 a.s.l., in an area known for widespread diffuse emissions of CO2 and other gases of magmatic origin. The preliminary data acquired so far showed an average soil CO2 efflux of 10 g m􀀀2 d􀀀1 (std dev of about 7 g m􀀀2 d􀀀1) and average 222Rn and 220Rn activities of about 3.3 103 Bq/m3 (std dev of about 1140 Bq/m3) and about 2.0 103 Bq/m3 (std dev of about 620 Bq/m3), respectively. The corresponding values of the SGDI thus obtained varied in the range from about -1.5 to about 70.1, with an average of about 7 and standard deviation of about 6.3. The apparent baseline of the parameter is around the value of 3, and daily variations are clearly detected due to the combined influence of air temperature and barometric pressure. No clear influence from rainfall was observed. Some spikes were also detected, whose origin has to be studied by correlating the SGDI with other environmental parameters as well as with changes in the volcanic/tectonic activity of Mt. Etna.
    Beschreibung: INGV, Sezione di Catania
    Beschreibung: Published
    Beschreibung: Vienna, Austria
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: open
    Schlagwort(e): Mt. Etna ; soil radon ; CO2 ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
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    Spectral properties of volcanic materials from hyperspectral field and satellite data compared with LiDAR data at Mt. Etna (2009)
    ELSEVIER
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Spectral properties of volcanic materials in the optical region (350–2500 nm) of the electromagnetic spectrum are analyzed. The goal is to characterize air-fall deposits, recent lava flows, and old lava flows based on their spectral reflectance properties and on the textural characteristics (grain size) of pyroclastic deposits at an active basaltic volcano. Data were acquired during a spectroradiometric field survey at Mt. Etna (Italy) in summer 2003 and combined with hyperspectral satellite (Hyperion) and airborne LiDAR (Light Detection and Ranging) data. In addition, air-fall deposits produced by the highly explosive 2002–2003 eruption have been sampled and spectrally characterized at different distances from the new vents. The spectral analysis shows that air-fall deposits are characterized by low reflectance values besides variations in grain size. This distinguishes them from other surface materials. Old lava flows show highest reflectance values due to weathering and vegetation cover. The spectral data set derived from the field survey has been compared to corrected satellite hyperspectral data in order to investigate the Hyperion capabilities to differentiate the surface cover using the reflectance properties. This has allowed us to identify the 2002–2003 air-fall deposits in a thematic image just few months after their emplacement. Moreover, the observed differences in the field spectra of volcanic surfaces have been compared with differences in the signal intensity detected by airborne LiDAR survey showing the possibility to include information on the texture of volcanic surfaces at Mt. Etna. The approach presented here may be particularly useful for remote and inaccessible volcanic areas and also represents a potentially powerful tool for the exploration of extraterrestrial volcanic surfaces.
    Beschreibung: Italian National Group of Volcanology
    Beschreibung: Published
    Beschreibung: 142-155
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mt. Etna ; Lava ; Reflectance spectra ; Hyperion ; LiDAR ; 04. Solid Earth::04.01. Earth Interior::04.01.99. 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::04.08. Volcanology::04.08.99. General or miscellaneous ; 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 ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 40
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    Relationship between soil CO2 flux and volcanic tremor at Mt. Etna: Implications for magma dynamics (2009)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Large variations of the CO2 flux through the soil were observed between November 2002 and January 2006 at Mt. Etna volcano. In many cases, the CO2 flux was strongly influenced by changes in air temperature and atmospheric pressure. A new filtering method was then developed to remove the atmospheric influences on soil CO2 flux and, at the same time, to highlight the variations strictly related to volcanic activity. Successively, the CO2 corrected data were quantitatively compared with the spectral amplitude of the volcanic tremor by cross correlation function, cross-wavelet spectrum and wavelet coherence. These analyses suggested that the soil CO2 flux variations preceded those of volcanic tremor by about 50 days. Given that volcanic tremor is linked to the shallow (a few kilometer) magma dynamics and soil CO2 flux related to the deeper (*12 km b.s.l.) magma dynamics, the “delayed similarity” between the CO2 flux and the volcanic tremor amplitude was used to assess the average speed in the magma uprising into the crust, as about 170–260 m per day. Finally, the large amount of CO2 released before the onset of the 2004–2005 eruption indicated a deep ingression of new magma, which might have triggered such an eruption.
    Beschreibung: In press
    Beschreibung: N/A or not JCR
    Beschreibung: reserved
    Schlagwort(e): Mt. Etna ; Soil CO2 flux ; Volcanic tremor ; Cross-wavelet spectrum ; Wavelet coherence ; Cross correlation function ; 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::05.02.02. Seismological data
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  • 41
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    Petrology of lavas from the 2004–2005 flank eruption of Mt. Etna, Italy: inferences on the dynamics of magma in the shallow plumbing system (2009)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Following the 2001 and 2002–2003 flank eruptions, activity resumed at Mt. Etna on 7 September 2004 and lasted for about 6 months. This paper presents new petrographic, major and trace element, and Sr–Nd isotope data from sequential samples collected during the entire 2004–2005 eruption. The progressive change of lava composition allowed defining three phases that correspond to different processes controlling magma dynamics inside the central volcano conduits. The compositional variability of products erupted up to 24 September is well reproduced by a fractional crystallization model that involves magma already stored at shallow depth since the 2002–2003 eruption. The progressive mixing of this magma with a distinct new one rising within the central conduits is clearly revealed by the composition of the products erupted from 24 September to 15 October. After 15 October, the contribution from the new magma gradually becomes predominant, and the efficiency of the mixing process ensures the emission of homogeneous products up to the end of the eruption. Our results give insights into the complex conditions of magma storage and evolution in the shallow plumbing system of Mt. Etna during a flank eruption. Furthermore, they confirm that the 2004–2005 activity at Etna was triggered by regional movements of the eastern flank of the volcano. They caused the opening of a complex fracture zone extending ESE which drained a magma stored at shallow depth since the 2002–2003 eruption. This process favored the ascent of a different magma in the central conduits, which began to be erupted on 24 September without any significant change in eruptive style, deformation, and seismicity until the end of eruption.
    Beschreibung: Published
    Beschreibung: 781–793
    Beschreibung: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Geochemistry ; Isotopic compositions ; Magma feeding system ; Magma mixing ; Mt. Etna ; 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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  • 42
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    Effusive Activity at Mount Etna Volcano (Italy) During the 20th Century: A Contribution to Volcanic Hazard Assessment (2008)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Mount Etna is an open conduit volcano, characterised by persistent activity, consisting of degassing and explosive phenomena at summit craters, frequent flank eruptions, and more rarely, eccentric eruptions. All eruption typologies can give rise to lava flows, which represent the greatest hazard by the volcano to the inhabited areas. Historical documents and scientific papers related to the 20th century effusive activity have been examined in detail, and volcanological parameters have been compiled in a database. The cumulative curve of emitted lava volume highlights the presence of two main eruptive periods: (a) the 1900–1971 interval, characterised by a moderate slope of the curve, amounting to 436 · 106 m3 of lava with average effusion rate of 0.2 m3/s and (b) the 1971–1999 period, in which a significant increase in eruption frequency is associated with a large issued lava volume (767 · 106 m3) and a higher effusion rate (0.8 m3/s). The collected data have been plotted to highlight different eruptive behaviour as a function of eruptive periods and summit vs. flank eruptions. The latter have been further subdivided into two categories: eruptions characterised by high effusion rates and short duration, and eruptions dominated by low effusion rate, long duration and larger volume of erupted lava. Circular zones around the summit area have been drawn for summit eruptions based on the maximum lava flow length; flank eruptions have been considered by taking into account the eruptive fracture elevation and combining them with lava flow lengths of 4 and 6 km. This work highlights that the greatest lava flow hazard at Etna is on the south and east sectors of the volcano. This should be properly considered in future land-use planning by local authorities.
    Beschreibung: Published
    Beschreibung: 407–443
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mt. Etna ; effusive activity ; database ; lava flow length ; eruptive fractures ; vent elevation ; hazard zonation ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
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    Volcanic tremor at Mt. Etna: Inferences on magma dynamics during effusive and explosive activity (2008)
    ELSEVIER
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: During 1999, the volcanic activity at Mt. Etna was both explosive and effusive at the summit craters: Strombolian activity, lava fountains and lava flows affected different areas of the volcano, involving three of the four summit craters. Results from analysis of the 1999 volcanic tremor features are shown at two different time scales. First, the long-term time variation of the features of the volcanic tremor (including spectral and polarization parameters), during the entire year, was compared with the evolution of the eruptive activity. This approach demonstrated the good agreement between tremor data and observed eruptive activity; the activation of different tremor sources was suggested. Then, a more refined analysis of the volcanic tremor, recorded during 14 lava fountain eruptions, was performed. In particular, a shift of the dominant frequencies towards lower values was noted which corresponds with increasing explosive activity. Similar behaviour in the frequency content has already been observed in other explosive eruptions at Mt. Etna as well as on other volcanoes. This behaviour has been explained in terms of either an increase in the tremor source dimension or a decrease in the sound speed in the magma within the conduit. These results confirm that the volcanic tremor is a powerful tool for better understanding the physical processes controlling explosive eruptions at Mt. Etna volcano.
    Beschreibung: Published
    Beschreibung: 19-31
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mt. Etna ; volcanic tremor ; spectral and polarization analysis ; effusive and explosive activity ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 44
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    Volcanological inferences from seismic-strain tensor computations at Mt. Etna Volcano, Sicily (2008)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Kostrov's (1974) algorithm for seismic-strain tensor computations, in the version implemented by Wyss et al. (1992a) for error estimates, has been applied to shear-type earthquakes occurring beneath the Etna volcano during 1990-1996. Space-time variations of strain orientations and amplitudes have been examined jointly with ground-deformation and gravimetric data collected in the same period and reported in the literature. Taking also into account the information available from volcanological observations and structural geology, we propose a model assuming that hydraulic pressure by magma emplaced in nearly north-south vertical structures produces the E-W orientation of the maximum compressive strain found in the upper 10 km beneath the crater area. In contrast, regional tectonics deriving from the slow, north-south convergence between the African and European plates appear to play a dominant role in the generation of stress and strain fields at crustal depths deeper than 10 km below the volcano. According to our interpretation, the progressive ascent of magma through the upper crust prior to eruption produces the observed gravity changes, cone inflation and unusual seismic strain rate in the upper 10 km associated with a more sharply defined seismic deformation regime (i.e. very small confidence limits of the epsilon 1 orientation). In agreement with this model, deflation revealed by ground-deformation data during the course of the major 1991-1993 eruption was accompanied by a practically nil level of shallow seismicity.
    Beschreibung: Published
    Beschreibung: 318-330
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Mt. Etna ; Italy ; Earthquakes ; Seismic strain ; Stress inversion ; Volcanic processes ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 45
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    Observations of Mt. Etna volcanic ash plumes in 2006: an integrated approach from ground-based and polar satellite NOAA-AVHRR monitoring system (2008)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Mt. Etna, in Sicily (Italy), is one of the world’s most frequent emitters of volcanic plumes. During the last ten years, Etna has produced copious tephra emission and fallout that have damaged the inhabited and cultivated areas on its slopes and created serious hazards to air traffic. Recurrent closures of the Catania International airport have often been necessary, causing great losses to the local economy. Recently, frequent episodes of ash emission, lasting from a few hours to days, occurred from July to December 2006, necessitating a look at additional monitoring techniques, such as remote sensing. The combination of a ground monitoring system, with polar satellite data represents a novel approach to monitor Etna’s eruptive activity and makes Etna one of the few volcanoes for which this surveillance combination is routinely available. In this work, ash emission information derived from an integrated approach, based on comparing ground and NOAA-AVHRR polar satellite observations, is presented. This approach permits us to define the utility of real time satellite monitoring systems for both sporadic and continuous ash emissions. Using field data (visible observations, collection of tephra samples and accounts by local inhabitants), the duration and intensity of most of the tephra fallout events were evaluated in detail and, in some cases, the order of magnitude of the erupted volume was estimated. The ground data vs. satellite data comparison allowed us to define five different categories of Etna volcanic plumes according to their extension and length, while taking into account plume height and wind intensity. Using frequent and good quality satellite data in real time, this classification scheme could prove helpful for investigations into a possible correlation between eruptive intensity and the presence and concentration of ash in the volcanic plume. The development and improvement of this approach may constitute a powerful warning system for Civil Protection, thus preventing unnecessary airport closures.
    Beschreibung: FIRB B5 Italian project “Sviluppo Nuove Tecnologie per la Protezione e Difesa del Territorio dai Rischi Naturali” funded by MIUR
    Beschreibung: Published
    Beschreibung: 135–147
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): volcanic ash ; Mt. Etna ; ground monitoring ; NOAA–AVHRR ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 46
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    Lava effusion rate definition and measurement: a review (2007)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Measurement of effusion rate is a primary objective for studies that model lava flow and magma system dynamics, as well as for monitoring efforts during on-going eruptions. However, its exact definition remains a source of confusion, and problems occur when comparing volume flux values that are averaged over different time periods or spatial scales, or measured using different approaches. Thus our aims are to: (1) define effusion rate terminology; and (2) assess the various measurement methods and their results. We first distinguish between instantaneous effusion rate, and time-averaged discharge rate. Eruption rate is next defined as the total volume of lava emplaced since the beginning of the eruption divided by the time since the eruption began. The ultimate extension of this is mean output rate, this being the final volume of erupted lava divided by total eruption duration. Whether these values are total values, i.e. the flux feeding all flow units across the entire flow field, or local, i.e. the flux feeding a single active unit within a flow field across which many units are active, also needs to be specified. No approach is without its problems, and all can have large error (up to ∼50%). However, good agreement between diverse approaches shows that reliable estimates can be made if each approach is applied carefully and takes into account the caveats we detail here. There are three important factors to consider and state when measuring, giving or using an effusion rate. First, the time-period over which the value was averaged; second, whether the measurement applies to the entire active flow field, or a single lava flow within that field; and third, the measurement technique and its accompanying assumptions.
    Beschreibung: Published
    Beschreibung: 1-22
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Lava ; Instantaneous effusion rate ; Time-averaged discharge rate ; Eruption rate ; Monitoring ; 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
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  • 47
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    Review of Microgravity Observations at Mt. Etna: A Powerful Tool to Monitor and Study Active Volcanoes. (2007)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Microgravity observations at Mt. Etna have been routinely performed as both discrete (since 1986) and continuous (since 1998) measurements. In addition to describing the methodology for acquiring and reducing gravity data from Mt. Etna, this paper provides a collection of case studies aimed at demonstrating the potential of microgravity to investigate the plumbing system of an active volcano and detect forerunners to paroxysmal volcanic events. For discrete gravity measurements, results from 1994– 1996 and 2001 are reported. During the first period, the observed gravity changes are interpreted within the framework of the Strombolian activity which occurred from the summit craters. Gravity changes observed during the first nine months of 2001 are directly related to subsurface mass redistributions which preceded, accompanied and followed the July-August 2001 flank eruption of Mt. Etna. Two continuous gravity records are discussed: a 16-month (October 1998 to February 2000) sequence and a 48-hour (26–28 October, 2002) sequence, both from a station within a few kilometers of the volcano’s summit. The 16-month record may be the longest continuous gravity sequence ever acquired at a station very close to the summit zone of an active volcano. By cross analyzing it with contemporaneous discrete observations along a summit profile of stations, both the geometry of a buried source and its time evolution can be investigated. The shorter continuous sequence encompasses the onset of an eruption from a location only 1.5 km from the gravity station. This gravity record is useful for establishing constraints on the characteristics of the intrusive mechanism leading to the eruption. In particular, the observed gravity anomaly indicates that the magma intrusion occurred ‘‘passively’’ within a fracture system opened by external forces.
    Beschreibung: Published
    Beschreibung: 769-790
    Beschreibung: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mt. Etna ; microgravity ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations
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  • 48
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    Reply to: comments to: “Volcanic geomorphology and tectonics of the Aeolian Archipelago (Southern Italy) based on integrated DEMdata” by Favalli et al. (2007)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: No abstract
    Beschreibung: Published
    Beschreibung: 117-118
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): geomorphology ; tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 49
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    High precision locations of LP events on Mt. Etna: reconstruction of the fluid-filled volume (2007)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: During 1991−93 at Mount Etna, long-period (LP) events occurring in swarms characterized the evolution of the eruption. The presence of multiplets i.e. groups of events with similar waveform signatures, has been recognized within this activity. Traditional techniques for locating LP events do not allow obtaining reliable hypocenters, which have only succeeded in placing earthquakes in a roughly 1 km2 area slightly east of the Mt. Etna Northeast Crater. Hypocenters have been relocated in two steps: the absolute location has been improved using Thurber’s code and a complex 3D velocity model; a highly precise relative location has been applied on multiplets to define the source geometry. 3D locations and high precision analysis suggest that during the 1991−93 eruption the resonator producing LP events was a part of the uppermost Northeast Crater conduit, measuring 210 meters in height and 45−50 meters in diameter.
    Beschreibung: Published
    Beschreibung: 663-674
    Beschreibung: reserved
    Schlagwort(e): waveform correlation ; stacked events ; 1991−93 eruption ; conduct geometry ; Mt. Etna Northeast Crater ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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    The role of the Pernicana Fault System in the spreading of Mt. Etna (Italy) during the 2002-2003 eruption (2005)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Flank instability and collapse are observed at many volcanoes. Among these, Mt. Etna is characterized by the spreading of its eastern and southern flanks. The eastern spreading area is bordered to the north by the EW-trending Pernicana Fault System (PFS). During the 20022003 Etna eruption, ground fracturing along the PFS migrated eastward from the NE Rift, to as far as the 18 km distant coastline. The deformation consisted of dextral en-echelon segments, with sinistral and normal kinematics. Both of these components of displacement were one order of magnitude larger (~1 m) in the western, previously known, portion of the PFS with respect to the newly surveyed (~9 km long) eastern section (~0.1 m). This eastern section is located along a pre-existing, but previously unknown, fault, where displaced man-made structures give overall slip rates (11.9 cm/year), only slightly lower than those calculated for the western portion (1.42.3 cm/year). After an initial rapid motion during the first days of the 20022003 eruption, movement of the western portion of the PFS decreased dramatically, while parts of the eastern portion continued to move. These data suggest a model of spreading of the eastern flank of Etna along the PFS, characterized by eruptions along the NE Rift, instantaneous, short-lived, meter-scale displacements along the western PFS and more long-lived centimeter-scale displacements along the eastern PFS. The surface deformation then migrated southwards, reactivating, one after the other, the NNWSSE-trending Timpe and Trecastagni faults, with displacements of ~0.1 and ~0.04 m, respectively. These structures, along with the PFS, mark the boundaries of two adjacent blocks, moving at different times and rates. The new extent of the PFS and previous activity over its full length indicate that the sliding eastern flank extends well below the Ionian Sea. The clustering of seismic activity above 4 km b.s.l. during the eruption suggests a deep décollement for the moving mass. The collected data thus suggests a significant movement (volume 〉1,100 km3) of the eastern flank of Etna, both on-shore and off-shore.
    Beschreibung: Published
    Beschreibung: 417-430
    Beschreibung: partially_open
    Schlagwort(e): Volcano spreading ; Fracturing ; Mt. Etna ; Pernicana Fault System ; NE Rift ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Format: 523 bytes
    Format: 998206 bytes
    Format: text/html
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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