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Rates of carbon dioxide plume degassing from Mount Etna volcano

2006; American Geophysical Union; Volume: 111; Issue: B9 Linguagem: Inglês

10.1029/2006jb004307

2156-2202

Alessandro Aiuppa, Cinzia Federico, Gaetano Giudice, Sergio Gurrieri, Marco Liuzzo, Hiroshi Shinohara, Rocco Favara, M. Valenza,

CO2 Sequestration and Geologic Interactions

We report here on the real‐time measurement of CO 2 and SO 2 concentrations in the near‐vent volcanic gas plume of Mount Etna, acquired by the use of a field portable gas analyzer during a series of periodic field surveys on the volcano's summit. During the investigated period (September 2004 to September 2005), the plume CO 2 /SO 2 ratio ranged from 1.9 to 10.8, with contrasting composition for Northeast and Voragine crater plumes. Scaling the above CO 2 /SO 2 ratios by UV spectroscopy determined SO 2 emission rates, we estimate CO 2 emission rates from the volcano in the range 0.9–67.5 kt d −1 (average, 9 kt d −1 ) . About 2 kt of CO 2 were emitted daily on average during quiescent passive degassing, whereas CO 2 emission rates from Etna's summit were 10–40 times larger during the 2004–2005 effusive event (with a cumulative CO 2 release of ∼3800 kt during the 6 months of the eruption). Such a syneruptive increase, ascribed to the replenishment of the shallow (<6 km) volcanic plumbing system by CO 2 ‐rich (0.25 wt %) more primitive magmas, supports the potential of CO 2 output rates as key parameters for volcanic hazard assessment.