Field measurements of volcanic gases using tunable diode laser based mid-infrared and Fourier transform infrared spectrometers

• Published in: Optics and lasers in engineering Vol. 37; no. 2; pp. 171 - 186
• Main Authors: Richter, Dirk, Erdelyi, Miklos, Curl, Robert F., Tittel, Frank K., Oppenheimer, Clive, Duffell, Hayley J., Burton, Mike
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2002; Elsevier
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Geochemistry; Mid-infrared absorption spectroscopy; Optical frequency conversion; Soil and rock geochemistry; Volcanic gases; Nicaragua; Masaya; Optical frequency conversion; Mid-infrared absorption spectroscopy; Volcanic gases; Central America; carbon dioxide; sulfur dioxide; laser methods; Fourier transformation; isotope ratios; C-13/C-12; field studies; water; volcanism; instruments; isotopes; methane; gases; chemical analysis methodology; absorption spectra; infrared spectroscopy
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/S0143-8166(01)00094-X

The first field measurements of volcanic gases using mid-IR difference frequency laser spectroscopy are reported. The results were obtained at the summit crater of Masaya volcano, Nicaragua, with the gases being drawn into a multi-pass cell and measured at reduced pressure. Automated sensitive and selective detection of CO 2, SO 2, H 35,37Cl, H 2O, and CH 4 was achieved. Simultaneous measurements obtained with open-path Fourier transform spectroscopy provide a useful comparison of the two optical techniques. We also consider the potential measurement of CO 2 isotopic ratios in volcanic gases using laser-based spectroscopy.