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  • 1
    ISSN: 1365-3121
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Recent geological studies performed at Etna allow reassessing the stratigraphic frame of the volcano where distinct evolutionary phases are defined. This stratigraphic reconstruction was chronologically constrained on the basis of a limited number of U–Th and K–Ar age determinations whose uncertainty margins are sometimes too wide. For this reason, we successfully adopted at Etna the 40Ar/39Ar technique that allowed obtaining more precise age determinations. The incremental heating technique also gives information on sample homogeneity, and potential problems of trapped argon. Five samples were collected from stratigraphically well-controlled volcanic units in order to chronologically define the transition between the fissure-type volcanism of the Timpe phase to the central volcanism of the Valle del Bove Centers. Isotopic ages with an uncertainty margin of 2–4% have been obtained emphasizing that this transition occurred (130–126 ka) without significant temporal hiatus.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of earth sciences 89 (2000), S. 665-677 
    ISSN: 1437-3262
    Keywords: Tephrostratigraphy Tephrochronology Basaltic explosive eruptions Tephra marker beds Y1 tephra layer X4 tephra layer Quaternary Etna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract. The pyroclastic deposits of Etna have been correlated over the whole volcanic edifice for the first time, allowing the construction of a continuous record of tephra-producing events, which extends from approximately 100 ka to the Present. In this interval, five main periods of explosive activity have been identified: (a) ∼100-ka strombolian to subplinian activity; (b) 80- to 100-ka plinian benmoreitic activity; (c) 16- to 80-ka strombolian to subplinian from basaltic to mugearitic activity; (d) 15.5- to 15-ka plinian benmoreitic activity accompanying the caldera-forming eruptions of the Ellittico Volcano; and (e) the most recent 13-ka basaltic explosive activity of strombolian and subplinian type of the present edifice that also includes the 122-B.C. plinian eruption. This study results in a semi-quantitative and in some cases quantitative definition of the intensity and chronology of the explosive activity at Etna. Moreover, this work gives a new significance to the volcanic hazards of Etna, a volcano generally considered to be the site of gentle effusive eruptions.
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  • 3
    Publication Date: 2011-10-01
    Description: Since the 1970’s, about 50 radio-isotopic ages have been determined on Etna volcanics using different techniques: Th-U and K/Ar. Unfortunately, these ages cannot be readily used to constrain the new stratigraphic setting of the volcano, because of the uncertainty in sample locations or, sometimes, the large errors affecting the calculated ages. For this reason a program of radio-isotopic dating applying the 40Ar/39Ar incremental heating technique to date the groundmass of basaltic samples has been carried out from 2002. Forty samples (22 of which are of new publication) were collected from key outcrops on Etna volcano, selected on the basis of their stratigraphic position, while one sample was collected from the Hyblean plateau volcanics. We have obtained reliable results from all volcanics analysed from 542 ka up to 10 ka with the MSWD’s (Mean Square of Weighted Deviates) ranging from 0.03 up to 1.7 excluding IS sample (MSWD = 6.28). These new results allow us to: i) assign an age to 19 of the 25 lithostratigraphic units defined in the new geological map of Etna volcano; ii) clarify the uncertain stratigraphic position of isolated volcanic units; iii) constraint the temporal hiatus that matches the main unconformities; iv) outline the lapse of time between the end of the Hyblean volcanism and the beginning of eruptive activity in the Etna region.
    Print ISSN: 2038-1719
    Electronic ISSN: 2038-1727
    Topics: Geosciences
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  • 4
    Publication Date: 2011-10-01
    Description: The new geological map of Etna volcano at 1:50,000 scale represents a significant progress in the geological studies of this volcano over the last 30 years, coming after Waltershausen’s map published around the mid of 19th century, the first geological map of a large active volcano, and the Romanoet alii (1979) map published about a century later, both at 1:50,000 scale. Lithostratigraphy was used for mapping volcanic units and then Unconformity Bounded Units were applied to group lithostratigraphic units into synthems. In addition, lithosomes were exploited to better represent the spatial localization of different eruptive centres according to their morphology. On the whole, we identified 27 lithostratigraphic units, grouped into 8 synthems, and 9 volcanoes. In detail, effusive and explosive deposits generated by each eruption of Mongibello and, partially, Ellittico volcanoes were mapped as flow rank. This stratigraphic framework represents the best synthesis of the geological evolution of Etna volcano using the main unconformities recognized within its complex volcanic succession. In addition, we constrain the Etna volcanic succession and its lithostratigraphic units chronologically by radioisotope age determinations. On the basis of the outlined synthemic units, it was possible to divide Etna’s volcanic succession into 4 supersynthems, which correspond to 4 well-defined and spatially localized phases. The detailed reconstruction of the past eruptive activity allowed compiling the most accurate dataset in particular of the Holocene eruptions of Etna volcano, which will enable significantly improving the volcanic hazard assessment, together with petrological interpretation of erupted magmas and geophysical modelling of the volcano plumbing system.
    Print ISSN: 2038-1719
    Electronic ISSN: 2038-1727
    Topics: Geosciences
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  • 5
    Publication Date: 2011-10-01
    Description: An updated geological evolution model is presented for the composite basaltic stratovolcano of Mount Etna. It was developed on the basis of the stratigraphic setting proposed in the new geological map that was constrained by 40Ar/39Ar age determinations. Unconformity-bounded stratigraphy allows highlighting four main evolutionary phases of eruptive activity in the Etna region. The Basal Tholeiitic Supersynthem corresponds to a period, from about 500 to 330 ka, of scattered fissure-type eruptions occurring initially in the foredeep basin and then in a subaerial environment. From about 220 ka, an increase in the eruptive activity built a lava-shield during the Timpe Supersynthem. The central-type activity occurred at least 110 ka ago through the Valle del Bove Supersynthem. The earliest volcanic centres recognized are Tarderia, Rocche and Trifoglietto and later Monte Cerasa, Giannicola, Salifizio and Cuvigghiuni. During the Stratovolcano Supersynthem, from about 57 ka ago, the intense eruptive activity of Ellittico volcano formed a roughly 3600 m-high stratocone that expanded laterally, filling the Alcantara and Simeto paleovalleys. Finally, effusive activity of the last 15 ka built the Mongibello volcano. Its eruptive activity is mainly concentrated in three weakness zones in which the recurrent magma intrusion generates flank eruptions down to low altitude. The four main evolutionary phases may furnish constraints to future models on the origin of Etna volcano and help unravel the geodynamic puzzle of eastern Sicily.
    Print ISSN: 2038-1719
    Electronic ISSN: 2038-1727
    Topics: Geosciences
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  • 6
    Publication Date: 2012-06-01
    Description: This work deals with the dating of Mount Etna lava flows and eruptive fissure deposits to the last four millennia following field investigations and stratigraphic data (Brancaet alii, 2011a). We have studied 24 of these volcanic products, including 301 large samples, through high precision archeomagnetic dating checked by 226Ra-230Th radiochronology, thus providing additional material to the previous paper by Tanguyet alii (2007). In most cases our results allow attributing ages to the historical period, although two flows are shown to be prehistoric. For the historic lavas, archeomagnetic ages can be defined within decades, except for three of them that erupted during a time span (Greco-Roman epoch) when the geomagnetic field underwent little variation. Although 60% of these volcanics exhibit ages comprised between 700 AD and 1850, only one (1285) is mentioned by contemporary written accounts. We conclude that i) historical documents alone are insufficient to reconstruct a coherent sequence of eruptions, and ii) a multidisciplinary approach is necessary to obtain a comprehensive eruptive history of such a very active volcano, useful for both scientific and civil protection purposes, even for such a geologically recent period as that of the last 10 or 20 centuries. Thanks to these new archeomagnetic and 226Ra-230Th data coupled with stratigraphic data, a comprehensive volcanic history of the still-outcropping Mount Etna volcanics is now available for the last 2,400 years.
    Print ISSN: 2038-1719
    Electronic ISSN: 2038-1727
    Topics: Geosciences
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  • 7
    Publication Date: 2012-02-01
    Description: A new volcano-tectonic map of Etna volcano has been compiled through a morphotectonic analysis performed with detailed field mapping, high-resolution DEM and orthoimages, constrained by seismotectonic data. In this study, we present a homogeneous mapping of the volcano-tectonic and tectonic elements on the whole volcano, consistent with the updated knowledge on the geology and active tectonics observed in historical times. Details of the tectonic features occurring in the lower-middle part of the volcanic edifice, namely the more densely urbanized areas, are described; volcanic elements such as eruptive fissures, caldera and flank collapse rims affecting the upper sectors, are also reported. All the volcanic land-forms of Etna edifice have been generated by constructive and destructive volcanic processes largely during the last 15 ka activity of Mongibello volcano. DEM-derived images (e.g. slope and aspect maps) were produced and interpreted in order to identify fault-related surface features based on an explicit list of well-known elements of tectonic geomorphology. Subsequently, the morphotectonic mapping has been compared with field data on geologic marker offsets, as well as evidence of surface faulting, including coseismic displacements and creeping of historical and recent events. This combined approach has enabled classifying each element reported in the map as (i) exposed faults, (ii) buried faults and (iii) hidden faults. The analysis of slip-rates confirms the exceptional dynamics of the Pernicana fault, which is characterised by an almost constant slip-rate of 20–36 mm/a over the last 1000 years, while the Timpe fault zone and the structural system in the southern flank accommodate a relevant amount of deformation with slip-rates reported to range of ca. 2–4 mm/a. Finally, a seismotectonic model summarises the information regarding seismic hazard, with reference to the additional, potentially severe effects induced by surface faulting.
    Print ISSN: 2038-1719
    Electronic ISSN: 2038-1727
    Topics: Geosciences
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  • 8
    Publication Date: 2020-06-12
    Description: Volcanic eruptions comprise an important airborne hazard for aviation. Although significant events are rare, e.g. compared to the threat of thunderstorms, they have a very high impact. The current state of tools and abilities to mitigate aviation hazards associated with an assumed volcanic cloud was tested within an international demonstration exercise. Experts in the field assembled at the Schwarzenberg barracks in Salzburg, Austria, in order to simulate the sequence of procedures for the volcanic case scenario of an artificial eruption of the Etna volcano in Italy. The scope of the exercise ranged from the detection (based on artificial observations) of the assumed event to the issuance of early warnings. Volcanic-emission-concentration charts were generated applying modern ensemble techniques. The exercise products provided an important basis for decision-making for aviation traffic management during a volcanic-eruption crisis. By integrating the available wealth of data, observations and modelling results directly into widely used flight-planning software, it was demonstrated that route optimization measures could be implemented effectively. With timely and rather precise warnings available, the new tools and processes tested during the exercise demonstrated vividly that a vast majority of flights could be conducted despite a volcanic plume being widely dispersed within a high-traffic airspace over Europe. The resulting number of flight cancellations was minimal.
    Print ISSN: 1561-8633
    Electronic ISSN: 1684-9981
    Topics: Geography , Geosciences
    Published by Copernicus on behalf of European Geosciences Union.
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  • 9
    Publication Date: 2012-12-01
    Print ISSN: 1352-2310
    Electronic ISSN: 1873-2844
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences , Physics
    Published by Elsevier
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  • 10
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