Skip to main content


We’d like to understand how you use our websites in order to improve them. Register your interest.

Formation process of recent fumarolic gases at the Mt. Mihara summit peak of the Izu-Oshima volcano, Japan


We have investigated the chemical and isotopic composition of recently formed gases emitted by three fumaroles on the Mt. Mihara summit peak of the Izu-Oshima volcano in order to assess the formation process of these gases. The CO2/H2O ratio of these gases varied greatly, with the σD and σ18O of the H2O being as low as a vapor phase equilibrated with the local meteoric water. These features are explained by a mixing of the vapor equilibrated with local meteoric groundwater and primary steam, which is a vapor phase generated by the mixing of magmatic gas and a cold meteoric groundwater. We concluded that there was no direct mixing between the magmatic vapor and a vapor phase of meteoric origin in the processes involved in fumarolic gas formation.


  1. Coleman, M. L., T. J. Shepherd, J. J. Durham, J. E. Rouse, and G. R. Moore, Reduction of water with zinc for hydrogen isotope analysis, Anal. Chem., 54, 993–995, 1982.

  2. Conway, E. J., Microdiffusion analysis and volumetric error, 3rd edn., Crosby-Lockwood, London, 1950.

  3. Epstein, S. and T. K. Mayeda, Variation of 18O content of waters from natural sources, Geochim. Cosmochim. Acta, 4, 213–224, 1953.

  4. Fujii, T., S. Aramaki, T. Kaneko, K. Ozawa, Y. Kawanabe, and T. Fukuoka, Petrology of the lava and ejecta of the November, 1986 eruption of Izu-Oshima volcano, Bull. Volcanol. Soc. Jpn., 33, S234–S254, 1988 (in Japanese with English abstract).

  5. Giggenbach, W. F., A simple method for the collection and analysis of volcanic samples, Bull. Volcanol., 39, 132–145, 1975.

  6. Giggenbach, W. F., Geothermal gas equilibria, Geochim. Cosmochim. Acta, 44, 2021–2032, 1980.

  7. Giggenbach, W. F., Isotopic shifts in waters from geothermal and volcanic systems along convergent plate boundaries and their origin, Earth Planet. Sci. Lett., 113, 495–510, 1992.

  8. Giggenbach, W. F and M. K. Stewart, Processes controlling the isotopic composition of steam and water discharges from steam vents and steam-heated pools in geothermal areas, Geothermics, 11, 71–80, 1982.

  9. Henley, R. W. and A. J. Ellis, Geothermal systems ancient and modern: A geochemical review, Earth Sci. Rev., 19, 1–50, 1983.

  10. Horita, J. and D. J. Wesolowski, Liquid-vapor fractionation of oxygen and hydrogen isotopes of water from the freezing to the critical temperature, Geochim. Cosmochim. Acta, 58, 3425–3437, 1994.

  11. Kawanabe, Y., Geological map of Izu-Oshima volcano. Geological map of volcanoes, Geological Survey of Japan, 1998.

  12. Kazahaya, K., M. Takahashi, and A. Ueda, Discharge model of fumarolic gases during post-eruptive degassing of Izu-Oshima volcano, Japan, Geochem. J., 27, 261–270, 1993.

  13. Korzhinsky, M. A., R. E. Botcharnikov, S. I. Tkachenko, and G. S. Steinberg, Decade-long study of degassing at Kudriavy volcano, Iturup, Kurile Islands (1990–1999): Gas temperature and composition variations, and occurrence of 1999 phreatic eruption, Earth Planets Space, 54, 337–347, 2002.

  14. Menyailov, I. A., L. P. Nikitina, V. N. Shapar, and V. P. Pilipenko, Temperature increase and chemical change of fumarolic gases at Momotombo volcano, Nicaragua, in 1982–1985: Are these indicators of a possible eruption?, J. Geophys.Res., 91, 12199–12214, 1986.

  15. Notsu, K., T. Mori, S. C. DoVale, H. Kagi, and T. Ito, Monitoring quiescent volcanoes by diffuse CO2 degassing: Case study of Mt. Fuji, Japan, Pure Appl. Geophys., 163, 825–835, 2006.

  16. Ohba, T., J. Hirabayashi, and M. Yoshida, Equilibrium temperature and redox state of volcanic gas at Unzen volcano, Japan, J. Volcanol. Geotherm. Res., 60, 263–272, 1994.

  17. Ossaka, J., J. Hirabayashi, and T. Ozawa, Chemical compositions of volcanic gases collected after the 1977 eruption of Usu volcano. Joint geophysical and geochemical observations: Usu volcano (September-December, 1982) and Tarumai volcano (September-October, 1983), 117–126, 1984 (in Japanese).

  18. Ozawa, T., Chemical analysis of volcanic gases: I. Chemical analysis of volcanic gases containing water vapor, hydrogen chloride, sulfur dioxide, hydrogen sulfide, carbon dioxide, etc., Geochem. Int., 5, 939–947, 1968.

  19. Sano, Y. and B. Marty, Origin of carbon in fumarolic gas from island arcs, Chem. Geol., 119, 265–274, 1995.

  20. Sano, Y., T. Gamo, K. Notsu, and H. Wakita, Secular variations of carbon and helium isotopes at Izu-Oshima volcano, Japan, J. Volcanol. Geotherm. Res., 64, 83–94, 1995.

  21. Sawa, T., T. Ohba, and J. Hirabayashi, The hydrothermal system beneath Ohwakudani on Hakone volcano, Japan: Traced by stable isotope ratio of H2O, J. Nucl. Sci. Technol., 43, 468–473, 2006.

  22. Shimoike, Y and K. Notsu, Continuous chemical monitoring of volcanic gas in Izu-Oshima volcano, Japan, J. Volcanol. Geotherm. Res., 101, 211–221, 2000.

  23. Shinohara, H., W. F. Giggenbach, K. Kazahaya, and J. W. Hedenquist, Geochemistry of volcanic gases and hot springs of Satsuma-Iwojima, Japan: Following Matsuo, Geochem. J., 27, 271–285, 1993.

  24. Suwa, A. and Y. Tanaka, The changes in the temperautres of the fumaroles in the crater of Miharayama, Oshima, in connection with the activities of the volcano, Bull. Volcanol. Soc. Japan, 13, 107–118, 1959.

  25. Takahashi, M., K. Abe, T. Noda, K. Kazahaya, N. Ando, and T. Soya, Koshimizu thermal spring formed in the 1986 eruption of Izu Oshima volcano, J. Balneological Soc. Jpn., 49, 176–185, 2000 (in Japanese with English abstract).

  26. Taran, Y. A., B. G. Pokrovskiy, and Y. M. Dubik, Isotope composition and origin of water in andesite magma, Trans. USSR Acad. Sci., 304, 199–202, 1990.

  27. Taran, Y., C. B. Connor, V. N. Shapar, A. A. Ovsyannikov, and A. A. Bilichenko, Fumarolic activity of Avachinsky and Koryaksky volcanoes, Kamchatka, from 1993 to 1994, Bull. Volcanol., 58, 441–448, 1997.

  28. Taran, Y., A. Bernard, J. C. Gavilanes, E. Lunezheva, A. Cortes, and M. A. Armienta, Chemistry and mineralogy of high-temperature gas discharges from Colima volcano, Mexico. Implications for magmatic gas? atmosphere interaction, J. Volcanol. Geotherm. Res., 108, 245–264, 2001.

  29. Taran, Y., J. C. Gavilanes, and A. Cortes, Chemical and isotopic composition of fumarolic gases and the SO2 flux from Volcan de Colima, Mexico, between the 1994 and 1998 eruptions, J. Volcanol. Geotherm. Res., 117, 105–119, 2002.

Download references

Author information



Corresponding author

Correspondence to Takeshi Ohba.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ohba, T. Formation process of recent fumarolic gases at the Mt. Mihara summit peak of the Izu-Oshima volcano, Japan. Earth Planet Sp 59, 1127–1133 (2007).

Download citation

Key words

  • Fumarolic gases
  • formation process
  • Izu-Oshima volcano
  • CO2/H2O ratio
  • σD and σ18O values