Publikationsdatum:
2017-04-04
Beschreibung:
Two distinct eruptive events characterize the volcanic activity at Mount Etna during the 2002 to 2005
period.We identified signals of magma ascent preceding these eruptions by geochemical monitoring of both
chemical composition and He-isotope ratio of gas emissions from five locations in the peripheral area of the
volcano. The geochemical signals are interpreted using the models proposed by Caracausi et al. (2003a,
2003b) and allow identification of episodes of magma ascent and estimation of the pressures of degassing
magma. As observed for the 2001 eruption (Caracausi et al., 2003b), magma ascent probably triggered the
onset of the 2002–2003 eruption, and minor events of magma ascent were observed between May and
December 2003. In contrast to the previous two eruptions, the 2004–2005 eruption was not preceded by
significant geochemical signals of volcanic unrest, suggesting that this eruption was mainly triggered by the
failure of the upper portion of the volcanic edifice under the magmatic hydrostatic pressure in the conduits.
High 3He/4He ratio revealed new volatile-rich magma accumulation. The 2002–2003 eruption was preceded
by a much shorter period of new magma accumulation from deep levels of the feeding system. Few minor
signals of magma migration were detected at some of the sites during the months preceding the 2004–2005
eruption, suggesting that the degassed 3He-depleted magma resident in the volcanic conduits was not
replaced by new volatile-rich magma. This is in agreement with the lack of explosive activity during the
2004–2005 eruption and with petrologic observations that the parent magma probably erupted in 2000 and
2001. New geochemical signals of magma ascent from the deep reservoir have been identified since June
2005, indicating that the volcanic activity of Mount Etna is evolving toward new pre-eruptive conditions.
Beschreibung:
Published
Beschreibung:
Q06008
Beschreibung:
JCR Journal
Beschreibung:
reserved
Schlagwort(e):
chemical composition
;
geochemical monitoring
;
He isotope
;
magma migration.
;
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
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