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Geochemical variations of air‐free crater fumaroles at Mt Etna: New inferences for forecasting shallow volcanic activity
Author(s) -
Martelli M.,
Caracausi A.,
Paonita A.,
Rizzo A.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl035118
Subject(s) - fumarole , impact crater , volcano , geology , magma , geochemistry , volcanic gases , volatiles , earth science , astrobiology , physics
We investigated the gas geochemistry of fumaroles close to the Voragine crater of Mt Etna that have a temperature of 90–95°C, are CO 2 ‐dominated, and have an air content as low as <1%. This is the first report of the monitoring of such air‐free fumaroles at the Etnean crater area—previous studies indicated an air contribution of 70% or more. The helium and carbon isotopes (Rc/Ra = 6.5 ± 0.4, δ 13 C CO2 = −1.7 ± 0.5‰) suggest that the released gas is directly related to the magmatic degassing. The fumaroles were sampled 12 times between June 2007 and June 2008, which revealed an increase in Rc/Ra from 6.1 to 6.9 that can be related to the increasing volcanic activity at the summit area of Mt Etna. These fumaroles offer a new tool for detecting magmatic processes (magma ascent, refilling, degassing, etc.), and will be useful for volcano surveillance.