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  • Articles  (5)
  • Open Access-Papers  (5)
  • 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous  (5)
  • Elsevier Science Limited  (5)
  • Elsevier  (1)
  • American Association for the Advancement of Science (AAAS)
  • Iranian Fisheries Science Research Institute
  • 2015-2019  (5)
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  • Open Access-Papers  (5)
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  • 1
    Publication Date: 2023-01-25
    Description: The MU-RAY detector has been designed to perform muon radiography of volcanoes. The possible use on the field introduces several constraints. First the electric power consumption must be reduced to the minimum, so that the detector can be solar-powered. Moreover it must be robust and transportable, for what concerns the front-end electronics and data acquisition. A 1m2 prototype has been constructed and is taking data at Mt.Vesuvius. The detector consists of modules of 32 scintillator bars with wavelength shifting fibers and silicon photomultiplier read-out. A dedicated front-end electronics has been developed, based on the SPIROC ASIC. An introduction to muon radiography principles, the MU-RAY detector description and results obtained in laboratory will be presented.
    Description: We acknowledge the support provided by the Istituto Nazionale di Fisica Nucleare(INFN). We wish to thank A.Brosfor the scintillator bars provided by FERMILAB-NICADD. We are grateful to Aldo Orlandi of the Laboratori Nazionali di Frascati of INFN for polishing and mirroring the fibers.
    Description: Published
    Description: 423-426
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: Muon radiography ; Muon detector ; SiPM ; Volcanoes ; Muography ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2017-04-04
    Description: This paper presents the results of an investigation carried out on young volcanic rocks from the Gedemsa and Fanta 'Ale complexes, located in the Main Ethiopian Rift, the site of an intense magmatism since Eocene–Oligocene. The earlier NW–SE direction of extension of the Rift, which generated NE–SW trending faults, rotated around E–W in Quaternary times, and produced the still active N to N–NE Wonji Fault System. The Gedemsa volcano is located in the central part of the Ethiopian Rift, about 100 km SE of Addis Ababa. It is characterized by a wide central caldera, about 8 km in diameter. The general stratigraphic sequence in the area includes, from base upwards, rift-floor ignimbrites, pantelleritic and subordinate trachytic pyroclastic deposits and lava flows and domes, and widespread basaltic deposits. The Fanta 'Ale volcanic complex is located in the northern part of the Main Ethiopian Rift, where the Afar depression begins. It is characterized by a summit caldera of which the diameter is about 4 km. This volcano erupted trachytic and rhyolitic lavas, whereas the most diffuse unit is an ignimbrite related to the caldera collapse. Explosive activity has occurred inside and outside the caldera, forming tuff cones and thick pumice-fallout deposits. The onlymafic unit is represented by a basaltic eruption that occurred in 1870 AD. Historical eruptions and intense fumarolic activity are evidence for the persistence activity of the Fanta 'Ale in this part of the Main Ethiopian Rift. New geochemical and Sr–Nd–Pb isotope data on representative samples from Gedemsa and Fanta 'Ale volcanoes are presented and discussed in order to shed light on the genesis of mafic and felsic magmas, the genetic link between them, and their possible interaction with the local crust. Volcanic rocks showa typicalmafic–felsic bi-modal distribution with fewintermediate terms (Daly Gap), as observed at regional scale along theMain Ethiopian Rift as well as on the plateau. Geochemical data and modeling suggest that magmas evolved mainly through fractional crystallization processes, accounting for the entire mafic–felsic compositional variation. However, Sr–Nd–Pb isotope data reveal also open-system evolution processes. The most differentiated, Sr-poor rhyolites suffered important low temperature contamination by shallow fluids of hydrothermal and/or meteoric origin. This affected mostly the Sr isotopic composition of whole-rocks, and much less that of separated feldspars that provide more reliable 87Sr/86Sr values.Mafic rocks, as well as the least contaminated felsic rocks, provide evidence for two components involved in the genesis and evolution of mafic magmas: a mantle component, carrying the isotopic composition of the Afar plume, and a crustal component, likely Pan-African sialic lower crust, that might have been added in smallamounts, about 2%, tomaficmagmas. The origin of the primarymagmas is inferred to have occurred by 7% partial melting of a mixed source region including both depleted and enriched mantle components
    Description: Published
    Description: 130-144
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: Main Ethiopian Rift ; Peralkaline magmas ; Mantle plume ; Crustal assimilation ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2020-11-20
    Description: In this paperwe trace the impact of the 1669 eruption and the 1693 earthquakes in eastern Sicily, their effects on the people living in the Etna region and, more particularly, in the city of Catania and its hinterland. The former event was the largest historic eruption of Etna, having a flow field with an area of ca. 40 km2 and a maximum flow length of ca. 17 km, whereas the latter – occurring only 24 years later – killed between 11,000 and 20,000 of Catania’s estimated 20–27,000 inhabitants, plus many more in smaller settlements. Using a combination of field-based research, contemporary accounts and archival sources, the authors are able to drawa number of conclusions. First, the 1669 eruption, although it did not kill or injure, was economically the most devastating of historical eruptions. Although it affected a limited area, inundation by lava meant that landwas effectively sterilized for centuries and, in a pre-industrial agriculturally-based economy, recovery could not occur quicklywithout outside assistance from the State. Indeed some of the worst affected municipalities (i.e. Comuni) were only able to support populations that were much reduced in size. Secondly, much of the damage caused to buildings by volcanic earthquakes was effectively masked, becausemost of the settlements affectedwere quickly covered by lava flows. The vulnerability to volcanic earthquakes of traditionally constructed buildings has, however, remained a serious example of un-ameliorated risk exposure through to the present day. A third conclusion is that the 1693 earthquakes, although more serious with respect to the number of people and the area they affected in terms of mortality, morbidity and their immediate economic impact, saw a rapid and sustained recovery. Thiswas due in part to the fact that, in contrast to lava flows, an earthquake does not sterilize land, but more significant was the reduction in population numberswhich served both to release and concentrate funds for investment in recovery. By the close of the eighteenth century Cataniawas knownthroughout Europe for the quality of its townscape and buildings, many of which were constructed in the then fashionable (and expensive) baroque style. Finally, the 1669 and 1693 disasters were seized on by the authorities as opportunities to plan new and re-build old settlementswith improved infrastructure to facilitate economic growth. By the nineteenth centurymany of the lessons had been largely forgotten and there were many examples of: poor seismic design of individual buildings; and the location of newresidential and commercial areas that placed more people at greater risk fromfuture extreme events. Indeed it is only recently have new regulations been enacted to prevent the construction of buildings in the vicinity of active faults and to control development in other hazardous zones.
    Description: Published
    Description: 25-40
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: Etna, 1669 eruption, 1693 earthquake, Resilience ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2021-05-12
    Description: An accelerating process of ground deformation that began 10 years ago is currently affecting the Campi Flegrei caldera. The deformation pattern is here explained with the overlapping of two processes: short time pulses that are caused by injection of magmatic fluids into the hydrothermal system; and a long time process of heating of the rock. The short pulses are highlighted by comparison of the residuals of ground deformation (fitted with an accelerating polynomial function) with the fumarolic CO2/CH4 and He/CH4 ratios (which are good geochemical indicators of the arrival of magmatic gases). The two independent datasets show the same sequence of five peaks, with a delay of ∼200 days of the geochemical signal with respect to the geodetic signal. The heating of the hydrothermal system, which parallels the long-period accelerating curve, is inferred by temperature–pressure gas geoindicators. Referring to a recent interpretation that relates variations in the fumarolic inert gas species to open system magma degassing, we infer that the heating is caused by enrichment in water of the magmatic fluids and by an increment in their flux. Heating of the rock caused by magmatic fluids can be a central factor in triggering unrest at calderas.
    Description: Published
    Description: 58-67
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Campi Flegrei Caldera ; hydrothermal system ; ground deformation ; magmatic fluids ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2017-04-04
    Description: During the ~8-year period between the 1991–93 and 2001 flank eruptions, the eruptive activity of Mt. Etna was confined to the summit craters. Deformation and tomography studies indicate that this activity was fed by a magma accumulation zone centered NE of the summit, at a depth of 5 to 9 km below sea level. The most significant gravity changesmeasured during the same period were induced bymass redistributions at shallower depth below the southeastern flank of the volcano, whereminor ground deformationwas observed (i.e., vertical displacementswithin 2cm). The mismatch between the position of pressure and mass sources is difficult to explain under the assumption that both are directly related to magma dynamics. Past studies have suggested that the gravity changes observed during 1994–2001 may primarily reflect changes in the rate of microfracturing along the NNW–SSE fracture/ weakness zone (FWZ) that crosses the SE slope of Etna. We use the finite element method to shed new light on the complex relations between stress, strain and mass changes that occurred at Etna during the studied period. In particular, following previous results on the degradation of themechanical properties of rocks,we performa set of simulations assuming that the part of themedium containing the FWZ is characterized by a lower Young's modulus than would be expected from interpolation of tomographic data.Wefind that the presence of theFWZ creates a distortion of the displacement field induced by the deeper pressure source, locally resulting in a weak extensional regime. This finding supports the hypothesis of a cause–effect relationship between pressurization beneath theNWflank and tensile extension beneath the SE slope of the volcano. Wepropose that this extensional regime enhanced the propagation of pressurized gas, that, in turn, amplified the tensile strain across the FWZ. We also find that decreasing the value of Young'smodulus in the FWZ allows for a larger amount of extension at depth, with no change in the magnitude of surface displacements. This result provides an indication of how the changes in the rate of microfracturing at depth,which are needed to induce the observed gravity changes,might have occurred without large ground deformation.
    Description: Published
    Description: 454–468
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Etna volcano ; Gravity changes ; Ground deformation ; Fracture zone ; Young's modulus ; Finite element method ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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