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Title
  • en Hydrogen isotopes in volcanic plumes: Tracers for remote temperature sensing of fumaroles
Creator
    • en Kamimura, Kanae
    • en Anzai, Saya
    • en Nakagawa, Fumiko
    • en Komatsu, Daisuke D.
Accessrights open access
Subject
  • Other en volcanic plume
  • Other en molecular hydrogen
  • Other en isotope exchange equilibrium
  • Other en remote temperature sensing
  • NDC 453
Description
  • Abstract en In high-temperature volcanic fumaroles (>400℃), the isotopic composition of molecular hydrogen (H2) reaches equilibrium with that of the fumarolic H2O. In this study, we used this hydrogen isotope exchange equilibrium of fumarolic H2 as a tracer for the remote temperature at volcanic fumaroles. In this remote sensing, we deduced the hydrogen isotopic composition (δD value) of fumarolic H2 from those in the volcanic plume. To ascertain that we can estimate the δD value of fumarolic H2 from those in a volcanic plume, we estimated the values in three fumaroles with outlet temperatures of 630℃ (Tarumae), 203℃ (Kuju), and 107℃ (E-san). For this we measured the concentration and δD value of H2 in each volcanic plume, along with those determined directly at each fumarole. The average and maximum mixing ratios of fumarolic H2 within a plume's total H2 were 97% and 99% (at Tarumae), 89% and 96% (at Kuju), and 97% and 99% (at E-san). We found a linear relationship between the depletion in the δD values of H2, with the reciprocal of H2 concentration. Furthermore, the estimated end-member δD value for each H2-enriched component (-260±3‰ vs. VSMOW in Tarumae, -509±23‰ in Kuju, and -437±14‰ in E-san) coincided well with those observed at each fumarole (-247.0±0.6‰ in Tarumae, -527.7±10.1‰ in Kuju, and -432.1±2.5‰ in E-san). Moreover, the calculated isotopic temperatures at the fumaroles agreed to within 20℃ with the observed outlet temperature at Tarumae and Kuju. We deduced that the δD value of the fumarolic H2 was quenched within the volcanic plume. This enabled us to remotely estimate these in the fumarole, and thus the outlet temperature of fumaroles, at least for those having the outlet temperatures more than 400℃. By applying this methodology to the volcanic plume emitted from the Crater 1 of Mt. Naka-dake (the volcano Aso) where direct measurement on fumaroles was impractical, we estimated that the δD value of the fumarolic H2 to be -172±16‰ and the outlet temperature to be 868±97℃. The remote temperature sensing using hydrogen isotopes developed in this study is widely applicable to many volcanic systems.
Publisher en Elsevier
Date
    Issued2011-08-15
Language
  • eng
Resource Type journal article
Version Type AM
Identifier HDL http://hdl.handle.net/2115/48356
Relation
  • isVersionOf DOI https://doi.org/10.1016/j.gca.2011.05.023
Journal
    • PISSN 0016-7037
      • en Geochimica et Cosmochimica Acta
      • Volume Number75 Issue Number16 Page Start4531 Page End4546
File
Oaidate 2023-07-26