Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy

O'Dwyer, M., Padgett, M. , McGonigle, A.J.S., Oppenheimer, C. and Inguaggiato, S. (2003) Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy. Geophysical Research Letters, 30(12), art -1652. (doi:10.1029/2003GL017246)

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Publisher's URL: http://dx.doi.org/10.1029/2003GL017246

Abstract

Sulphur speciation in volcanic gases acts as a major redox buffer, and H<sub>2</sub>S/SO<sub>2</sub> ratios represent a valuable indicator of magmatic conditions and interactions between magmatic and hydrothermal fluids. However, measurement of H<sub>2</sub>S/SO<sub>2</sub> even by direct sampling techniques, is not straightforward. We report here on application of a small ultraviolet spectrometer for real-time field measurement of H<sub>2</sub>S and SO<sub>2</sub> concentrations, using open-path and extractive configurations. The device was tested at fumaroles on Solfatara and Vulcano, Italy, in November 2002. H<sub>2</sub>S concentrations of up to 220 ppmm (400 ppmv) were measured directly above the Bocca Grande fumarole at Solfatara, and H<sub>2</sub>S/SO<sub>2</sub> molar ratios of 2 and 2.4, respectively, were determined for the 'F11' and 'F0' fumaroles at Vulcano. In comparison with other optical techniques capable of multiple volcanic gas measurements, such as laser and FTIR spectroscopy, this approach is considerably simpler and cheaper, with the potential for autonomous, sustained high-time resolution operation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Padgett, Professor Miles
Authors: O'Dwyer, M., Padgett, M., McGonigle, A.J.S., Oppenheimer, C., and Inguaggiato, S.
Subjects:Q Science > QE Geology
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Geophysical Research Letters
ISSN:0094-8276

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