Rates of carbon dioxide plume degassing from Mount Etna volcano

We report here on the real-time measurement of CO2 and SO2 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 CO2/SO2 ratio ranged
from 1.9 to 10.8, with contrasting composition for Northeast and Voragine crater plumes.
Scaling the above CO2/SO2 ratios by UV spectroscopy determined SO2 emission
rates, we estimate CO2 emission rates from the volcano in the range 0.9–67.5 kt d 1
(average, 9 kt d 1). About 2 kt of CO2 were emitted daily on average during quiescent
passive degassing, whereas CO2 emission rates from Etna’s summit were 10–40 times
larger during the 2004–2005 effusive event (with a cumulative CO2 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 CO2-rich (0.25 wt %)
more primitive magmas, supports the potential of CO2 output rates as key parameters for
volcanic hazard assessment.

Aiuppa, A., C. Federico, G. Giudice, S. Gurrieri, A. Paonita, and M. Valenza
(2004), Plume chemistry provides insights into the mechanisms of sulfur
and halogen degassing at basaltic volcanoes, Earth Planet. Sci. Lett., 222,
469–483.
Aiuppa, A., C. Federico, G. Giudice, and S. Gurrieri (2005a), Chemical
mapping of a fumarolic field: La Fossa Crater, Vulcano Island (Aeolian
Islands, Italy), Geophys. Res. Lett., 32, L13309, doi:10.1029/
2005GL023207.
Aiuppa, A., C. Federico, A. Franco, G. Giudice, S. Gurrieri, S. Inguaggiato,
M. Liuzzo, A. J. S. McGonigle, and M. Valenza (2005b), Emission of
bromine and iodine from Mount Etna volcano, Geochem. Geophys. Geosyst.,
6, Q08008, doi:10.1029/2005GC000965.
Allard, P. (1997), Endogenous magma degassing and storage at Mount
Etna, Geophys. Res. Lett., 24, 2219– 2222.
Allard, P., et al. (1991), Eruptive and diffuse emissions of CO2 from Mount
Etna, Nature, 351, 387– 391.
Allard, P., M. Burton, and F. Mure` (2005), Spectroscopic evidence for a
lava fountain driven by previously accumulated magmatic gases, Nature,
433, 407–410.
Armienti, P., R. Clocchiatti, M. D’Orazio, F. Innocenti, R. Petrini,
M. Pompilio, S. Tonarini, and L. Villari (1994), The long-standing
1991– 93 Mt. Etna eruption: Petrography and geochemistry of lavas, Acta
Volcanol., 4, 15–28.
Behncke, B., M. Neri, and A. Nagay (2005), Lava flow hazard at Mount
Etna (Italy): New data from a GIS-based study, in Kinematics and Dynamics
of Lava Flows, edited by M. Manga and G. Ventura, Spec. Pap.
Geol. Soc. Am., 396, 187– 205, doi:710.1130/2005.2396(13).
Berner, R. A., and A. C. Lasaga (1989), Modeling the geochemical carbon
cycle, Am. J. Sci., 260, 74– 81.
Brantley, S. L., and K. W. Koepenick (1995), Measured carbon dioxide
emissions from Oldoinyo Lengai and the skewed distribution of passive
volcanic fluxes, Geology, 23, 933–936.
Burton, M. R., C. Oppenheimer, L. A. Horrocks, and P. W. Francis (2000),
Remote sensing of CO2 and H2O emission rates from Masaya volcano,
Nicaragua, Geology, 28, 915– 918.
Burton, M. R., et al. (2005), Etna 2004–2005: An archetype for geodynamically-
controlled effusive eruptions, Geophys. Res. Lett., 32, L09303,
doi:10.1029/2005GL022527.
Caltabiano, T., M. Burton, S. Giammanco, P. Allard, N. Bruno, F. Mure`,
and R. Romano (2004), Volcanic gas emissions from the summit craters
and flanks of Mt. Etna, 1987– 2000, in Mt. Etna: Volcano Laboratory,
Geophys. Monogr. Ser., vol. 143, edited by A. Bonaccorso et al., pp. 111–
128, AGU, Washington, D. C.
Caracausi, A., F. Italiano, A. Paonita, A. Rizzo, and P. M. Nuccio (2003),
Evidence of deep magma degassing and ascent by geochemistry of
peripheral gas emissions at Mount Etna (Italy): Assessment of the magmatic
reservoir pressure, J. Geophys. Res., 108(B10), 2463,
doi:10.1029/2002JB002095.
Carroll, M. R., and J. R. Halloway (Eds.) (1994), Volatiles in Magmas, Rev.
Mineral., vol. 30, Mineral. Soc. of Am., Washington, D. C.
Carroll, M. R., and J. D. Webster (1994), Solubilities of sulfur, noble gases,
nitrogen, chlorine and fluorine in magmas, in Volatiles in Magmas, Rev.
Mineral., vol. 30, edited by M. R. Carroll and J. R. Halloway, pp. 231–
279, Mineral. Soc. of Am., Washington, D. C.
Casadevall, T., W. Rose, T. Gerlach, L. P. Greenland, J. Ewert,
R. Wunderman, and R. Symonds (1983), Gas emissions and the eruptions
of Mount St. Helens through 1982, Science, 221, 1383– 1385.
Chiarabba, C., A. Amato, E. Boschi, and F. Barberi (2000), Recent seismicity
and tomographic modeling of Mount Etna plumbing system, J. Geophys.
Res., 105, 10,923–10,938.
Chiodini, G., F. Frondini, C. Cardellini, D. Granieri, L. Marini, and
G. Ventura (2001), CO2 degassing and energy release at Solfatara volcano,
Campi Flegrei, Italy, J. Geophys. Res., 106, 16,213–16,221.
Clocchiatti, R., J. Weisz, M. Mosbah, and J. C. Tanguy (1992), Coexistence
de ‘‘verres’’ alcalins et thoe`liitiques sature`s en CO2 dans les olivines des
hyaloclastites d’Aci Castello (Etna, Sicilie, Italie). Arguments en faveur
d’un manteau anormal et d’un re`servoir profond, Acta Vulcanol., 2, 161–
173.
De Gori, P., C. Chiarabba, and D. Patane` (2005), Qp structure of Mount
Etna: Constraints for the physics of the plumbing system, J. Geophys.
Res., 110, B05303, doi:10.1029/2003JB002875.
Frondini, F. G. Chiodini, S. Caliro, C. Cardellini, D. Granieri, and
G. Ventura (2004), Diffuse CO2 degassing at Vesuvio, Italy, Bull. Volcanol.,
66, 642– 651, doi:10.1007/s00445-004-0346-x.
Gerlach, T. M. (1980), Investigation of volcanic gas analyses and magma
outgassing from Erta Ale lava lake, Afar, Ethiopia, J. Volcanol.
Geotherm. Res., 7, 415– 441.
Gerlach, T. M. (1991), Present-day CO2 emissions from volcanos, Eos
Trans. AGU, 72, 249, 254–255.
Gerlach, T. M., and E. J. Graeber (1985), Volatile budget of Kilauea Volcano,
Nature, 313, 273– 277.
Gerlach, T. M., H. Delgado, K. McGee, M. Doukas, J. Venegas, and
L. Cardenas (1997), Application of the Li-COR CO2 analyzer to volcanic
plumes: A case study, volcano Popocatepetl, Mexico, June 7 and 10, 1995,
J. Geophys. Res., 102, 8005– 8019.
Gerlach, T. M., K. A. McGee, A. J. Sutton, and T. Elias (1998), Rate of
volcanic CO2 degassing from airborne determinations of SO2 emission
rates and plume CO2/SO2: Test study at Pu’u ‘O’o cone, Kilauea volcano,
Hawaii, Geophys. Res. Lett., 25, 2675– 2678.
Gerlach, T. M., K. A. McGee, T. Elias, A. J. Sutton, and M. P. Doukas
(2002), Carbon dioxide emission rate of Kıcirc;lauea Volcano: Implications
for primary magma and the summit reservoir, J. Geophys. Res.,
107(B9), 2189, doi:10.1029/2001JB000407.
Giggenbach, W. F. (1996), Chemical composition of volcanic gases, in
Monitoring and Mitigation of Volcanic Hazards, edited by R. Scarpa
and R. I. Tilling, pp. 221– 256, Springer, New York.
Harris, D. M., andW. I. Rose (1996), Dynamics of carbon dioxide emissions,
crystallization, and magma ascent: Hypotheses, theory, and applications to
volcano monitoring at Mount St. Helens, Bull. Volcanol., 58, 163–174.
Holloway, J. R., and J. G. Blank (1994), Application of experimental results
to C-O-H species in natural melts, in Volatiles in Magmas, Rev. Mineral., vol. 30, edited by M. R. Carroll and J. R. Halloway, pp. 187 – 230,
Mineral. Soc. of Am., Washington, D. C.
Kamenetsky, V., and R. Clocchiatti (1996), Primitive magmatism of Mt.
Etna: Insights from mineralogy and melt inclusions, Earth Planet. Sci.
Lett., 142, 553– 572.
Koepenick, K. W., S. L. Brantley, J. M. Thompson, G. L. Rowe, A. A.
Nyblade, and C. Moshy (1996), Volatile emissions from the crater and
flank of Oldoinyo Lengai volcano, Tanzania, J. Geophys. Res., 101,
13,819–13,830.
McGonigle, A. J. S. (2005), Volcano remote sensing with ground-based
spectroscopy, Philos. Trans. R. Soc. London, Ser. A, 363, 2915–2929,
doi:10.1098/rsta.2005.1668.
Metrich, N., P. Allard, N. Spillardet, D. Andronico, and M. Burton (2004),
2001 flank eruption of the alkali- and volatile-rich primitive basalt responsible
for Mount Etna’s evolution in the last three decades, Earth
Planet. Sci. Lett., 228, 1– 17.
Moretti, R., P. Papale, and G. Ottonello (2003), A model for the saturation
of C-O-H-S fluids in silicate melts, in Volcanic Degassing, edited by
C. Oppenheimer, D. Pyle, and J. Barclay, Geol. Soc. Spec. Publ., 213, 81–
101.
Murru, M., C. Montuori, M. Wyss, and E. Privitera (1999), The locations of
magma chambers at Mt. Etna, Italy, mapped by b-values, Geophys. Res.
Lett., 26, 2553– 2556.
Neri, M., and V. Acocella (2006), The 2004– 05 Etna eruption: Implications
for flank deformation and structural behaviour of the volcano, J. Volcanol.
Geotherm. Res., in press.
Papale, P. (1999), Modeling of the solubility of a two-component H2O +
CO2 fluid in silicate liquids, Am. Mineral., 84, 477– 492.
Rymer, H., J. Cassidy, C. A. Locke, and J. B. Murray (1995), Magma
movements in Etna volcano associated with major 1991– 93 lava eruption:
Evidence from gravity and deformation, Bull. Volcanol., 57, 451–
461.
Shinohara, H. (2005), A new technique to estimate volcanic gas composition:
Plume measurements with a portable multi-sensor system, J. Volcanol.
Geotherm. Res., 143, 319– 333.
Shinohara, H., and J. Witter (2005), Volcanic gases emitted during mild
Strombolian activity of Villarrica volcano, Chile, Geophys. Res. Lett., 32,
L20308, doi:10.1029/2005GL024131.
Shinohara, H., K. Kazahaya, G. Saito, K. Fukui, and M. Odai (2003a),
Variation of CO2/SO2 ratio in volcanic plumes of Miyakejima: Stable
degassing deduced from heliborne measurements, Geophys. Res. Lett.,
30(5), 1208, doi:10.1029/2002GL016105.
Shinohara, H., K. Fukui, K. Kazahaya, and G. Saito (2003b), Degassing
process of Miyakejima volcano: Implications of gas emission rate and
melt inclusion data, in Melt Inclusions in Volcanic Systems, Adv. Volcanol.,
vol. 4, edited by B. De Vivo and B. Bodnar, pp. 147–161, Elsevier,
New York.
Sorey, M. L., W. C. Evans, B. M. Kennedy, C. D. Farrar, L. J. Hainsworth,
and B. Hausback (1998), Carbon dioxide and helium emissions from a
reservoir of magmatic gas beneath Mammoth Mountain, California,
J. Geophys. Res., 103, 15,303– 15,323.
Symonds, R. B., W. I. Rose, G. J. S. Bluth, and T. M. Gerlach (1994),
Volcanic-gas studies: Methods, results and applications, in Volatiles in
Magmas, Rev. Mineral., vol. 30, edited by M. R. Carroll and J. R.
Holloway, 1– 66, Mineral. Soc. of Am., Washington, D. C.
Wardell, L. J., P. R. Kyle, and C. Chaffin (2004), Carbon dioxide and
carbon monoxide emission rates from an alkaline intra-plate volcano:
Mt. Erebus, Antarctica, J. Volcanol. Geotherm. Res., 131, 109–121.
Werner, C., and S. L. Brantley (2000), CO2 emissions from the Yellowstone
volcanic system, J. Geophys. Res., 105, 10,831–10,846.
Williams, S. N., S. J. Schaefer, V. Calvache, and D. Lopez (1992), Global
carbon dioxide emission to the atmosphere by volcanoes, Geochim. Cosmochim.
Acta, 56, 1765– 1770.