Journal Title
Title of Journal: Bull Volcanol
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Abbravation: Bulletin of Volcanology
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Publisher
Springer-Verlag
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Authors: Carmelo Ferlito Marco Viccaro Eugenio Nicotra Renato Cristofolini
Publish Date: 2010/07/23
Volume: 72, Issue: 10, Pages: 1179-1190
Abstract
Over the last 2 years the south east crater SEC at Mt Etna Italy has been characterised by the intermittent emission of lava flows often accompanied by paroxysmal episodes with violent strombolian activity and/or lava fountains One of the most intense and intriguing episodes occurred on November 16 2006 during strombolian and effusive activity from the very top of the SEC At the eastern base of the crater a violent and shortlasting outburst generated a 300mhigh eruptive curtain of finely fragmented magma and steam which collapsed in a few seconds giving rise to a small but significant pyroclastic flow The paroxysm was preceded by progressive sliding of the eastern flank of the SEC edifice which led to the formation of a large niche Previously published models explain the outburst as due to rapid vaporisation of water contained in sediments on contact with hot lava flowing along the flank of the SEC or alternatively to gravitational collapse of a destabilised portion of the eastern flank of the crater However several lines of evidence suggest that these models do not adequately explain the paroxysm which we propose was associated with the explosive emission of magma during the rapid opening of an ESEWNWoriented fracture at the eastern base of the SEC Moreover geochemical data of the products associated with this episode show that they are the most primitive and gasrich among those erupted during the entire 2006 period We suggest that the paroxysm of November 16 2006 which occurred at base of the SEC was a magma outburst due to rapid ground fracturing related to a drop in confining pressure upon the underlying dyke consequent to the sliding of the eastern flank of the SEC cone Specifically the unloaded shallow portion of the feeding dyke did not restrain the arrival of a new batch of gasrich magma which worked its way out by fracturing the base of the niche at its weakest point This paroxysm appears significant because it reveals the potential development of syneruptive dynamics acting directly on the uppermost portion of the plumbing system which is able to generate pyroclastic flows even on basaltic volcanoes such as Mount EtnaWe would like to express our gratitude to RAI Italian Public Television for having kindly given permission to reproduce on the website http//etnalogosnet exclusively for scientific reasons the video filmed by G Tomarchio concerning the eruptive sequence of the November 16 2006 paroxysm which was vital to understanding the mechanism of the fracture opening The photo sequence of the pyroclastic flow in Fig 5 was provided by S Genovese B van Wyk de Vries is greatly acknowledged for his editorial guidance A Duncan T Druitt and A Harris contributed with their constructive suggestions to improve the quality of the earlier version of this paper This research was supported by grants from the University of Catania Research Projects 2005 and 2006 Recent Etna activity in the frame of regional volcanism Finally we wish to thank Dr M D Wilkinson for his revision of the English version of the manuscript
Keywords:
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Other Papers In This Journal:
- Mechanism of small vulcanian eruptions at Suwanosejima volcano, Japan, as inferred from precursor inflations and tremor signals
- Magma emplacement into the Lemptégy scoria cone (Chaîne Des Puys, France) explored with structural, anisotropy of magnetic susceptibility, and Paleomagnetic data
- Seismic characterisation of lahars at Volcán de Colima, Mexico
- Observations of volcanic tremor during the January–February 2005 eruption of Mt. Veniaminof, Alaska
- Evolution of the late Pleistocene Mojanda–Fuya Fuya volcanic complex (Ecuador), by progressive adakitic involvement in mantle magma sources
- Evolution of the late Pleistocene Mojanda–Fuya Fuya volcanic complex (Ecuador), by progressive adakitic involvement in mantle magma sources
- The November 2002 eruption of Piton de la Fournaise, Réunion: tracking the pre-eruptive thermal evolution of magma using melt inclusions
- The Cenozoic volcanic province of Tibesti (Sahara of Chad): major units, chronology, and structural features
- A melt viscosity scale for preeruptive magmas
- The ~AD1315 Tarawera and Waiotapu eruptions, New Zealand: contemporaneous rhyolite and hydrothermal eruptions driven by an arrested basalt dike system?
- Development of an automatic volcanic ash sampling apparatus for active volcanoes
- Geochemistry and magmatic properties of eruption episodes from Haroharo linear vent zone, Okataina Volcanic Centre, New Zealand during the last 10 kyr
- Geochemistry and magmatic properties of eruption episodes from Haroharo linear vent zone, Okataina Volcanic Centre, New Zealand during the last 10 kyr
- Finding of an historical document describing an eruption in the NW flank of Etna in July 1643 AD: timing, location and volcanic products
- Fault textures in volcanic conduits: evidence for seismic trigger mechanisms during silicic eruptions
- Role of magma mixing in the petrogenesis of tephra erupted during the 1990–98 explosive activity of Nevado Sabancaya, southern Peru
- Sheathfolds in rheomorphic ignimbrites
- Fragmentation in kimberlite: products and intensity of explosive eruption
- Geological constraints on the emplacement mechanism of the Parinacota debris avalanche, northern Chile
- Diverse mid-Miocene silicic volcanism associated with the Yellowstone–Newberry thermal anomaly
- Smithsonian Institution’s Global Volcanism Network
- Geometry and growth of sill complexes: insights using 3D seismic from the North Rockall Trough
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