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| Titel |
Magma supply and eruptive styles at Mt. Etna during the 2001-2009 period |
| VerfasserIn |
Renato Cristofolini, Carmelo Ferlito, Paolo Giacomoni Pier, Eugenio Nicotra, Marco Viccaro |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042857
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| Zusammenfassung |
| Starting from the summer 2001 and during the last 9 years, the eruptive activity occurred at several vents, located along fissures on the southern, northeastern and eastern flanks of the volcano. The articulated eruptive behavior in the considered period has been related to the uprise of geochemically distinct and volatile-rich magmas into the upper levels of the edifice through regional and local tectonic structures. On the basis of an extended geochemical database on whole rocks and mineral phases, we suggest that the composite eruptive behavior shown in this period by the volcano, that alternated strongly explosive to quietly effusive episodes, was chiefly due to the ingress of volatile-rich, fresh magma at shallow levels through fractures independent from the main feeding system. Due to its high volatile contents, when this magma exsolved a gas phase at depth and interacted with magmas residing in closed reservoirs, the mixed magma gave rise to intensely strombolian eruptions (e.g., 2001 and 2002-03 events). On the other hand, when the same magma ascended through extensional tectonic structures and made its way into the open-conduit, here it released its volatiles from summit craters through steady-state degassing, leading to effusive eruptions (e.g., 2004-05 event). However, the eruptive activity of the 2006-09 period does not fully match this scenario, since magmas with compositions and volatile contents similar to those of the previous events gave origin to episodes with extremely variegated eruptive behaviors, from wholly effusive to highly explosive, even through structures linked with the open-conduit system. In this period, the activity was generally persistent and was accompanied by short-lasting high-energy eruptive episodes. Such an eruptive behavior, characterized by a scarcity of relevant seismic phenomena, can be consistent with: (1) pulsating recharges and fast magma ascent occurring within the open-conduit system and/or (2) an intermittent tectonic control acting on the shallow feeding structures. This underlines the significant role of regional and volcano-depending tectonics and supports the idea that, at present, the open-conduit could not occasionally buffer sudden pulses of ascending volatile-rich magmas, giving then rise to violent phenomena even from the summit craters. |
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