@article{oai:nagoya.repo.nii.ac.jp:00028755,
 author = {Takahashi, Koji U. and Tsunogai, Urumu and Nakagawa, Fumiko and Sukigara, Chiho},
 journal = {Journal of Volcanology and Geothermal Research},
 month = {Oct},
 note = {The isotopic compositions (δ^2H and δ^18O) of fumarolic H2O emitted during volcanic eruptions can distinguish the type of eruption (magmatic or phreatic), but direct sampling of fumarolic H2O in eruptive volcanoes is often neither practical nor safe. In this study, we developed a new analytical system to safely determine the isotopic compositions of fumarolic H2O from the volcanic plume samples taken in glass bottles. The system consisted of stainless steel gas introduction line and a cavity ring-down spectroscopic unit. In the 1 L glass sample bottles, analytical precision (1σ) was estimated to be better than 2‰ and 0.3‰, respectively, when >3400 ppmv of H2O was introduced, and better than 3‰ (δ^2H) and 0.4‰ (δ^18O) when >1800 ppmv of H2O was introduced. The H2O concentration accuracy was better than 5%. Using this in-situ collection method and the analytical system, we determined the isotopic compositions of H2O in volcanic plume samples taken at Iwo-yama in the Kirishima volcano group (Japan), and deduced the isotopic composition of fumarolic H2O from the volcanic plume. The reciprocal of the H2O concentration in the plume samples showed a good linear relationship with the isotopic composition. The isotopic composition of fumarolic H2O from Iwo-yama estimated from the plume samples directly corresponded to the determined fumarolic H2O. This method improves upon previous analyses to obtain the isotopic compositions of fumarolic H2O, particularly by reducing tedious, time consuming, and dangerous sampling of water vapor at volcanic fumaroles.},
 pages = {232--240},
 title = {Stable hydrogen and oxygen isotopic compositions of water vapor in volcanic plumes sampled in glass bottles using cavity ring-down spectroscopy},
 volume = {384},
 year = {2019}
}