Chemical composition of volcanic gases in Japan

Temporal variation in the chemical composition (HCl/SO2) of volcanic gas associated with the volcanic activity of Aso Volcano, Japan

“…High HCl/SO 2 ratios of the volcanic gas up to 0.6 were reported after the intense volcanic activities in 1958 (Iwasaki et al, 1962) and 1977 (Ossaka et al, 1978). Subsequent monitoring during six months after the eruption in 1977 gave HCl/SO 2 ratios of 0.1-0.2 (Ossaka et al, 1978).…”

“…However, the variation of these ratios with volcanic activity differs among volcanoes: increases (e.g., Hirabayashi et al, 1982;Aiuppa et al, 2004) and decreases (e.g., Noguchi and Kamiya, 1963;Taran et al, 2002;Duffel et al, 2003) of these ratios are reported to be associated with increasing volcanic activity. In the case of Aso volcano, high HCl/SO 2 ratios were observed soon after intense eruptive activities, and subsequently decreased after the activities ceased (Iwasaki et al, 1962;Ossaka et al, 1978Ossaka et al, , 1984. Although these observations described sporadically the relation between the HCl/SO 2 ratio and volcanic activity, continuous and longer observation is needed to further understand this relation.…”

High SiF4/HF ratio detected in Satsuma-Iwojima volcano’s plume by remote FT-IR observation

“…Iwodake is the high temperature over 880 • C (Shinohara et al, 1993). The chemical and isotopic compositions and fluxes of Satsuma-Iwojima's fumarolic gases and hot spring waters have been studied by many researchers (Iwasaki et al, 1962;Kamada, 1964;Matsuo et al, 1974;Shinohara et al, 1993;Hedenquist et al, 1994). The measurements at Satsuma-Iwojima were carried out on October 16, 1996.…”

Volcanogenic Sulfur on Earth and Io: Composition and Spectroscopy

“…Some volcanic exhalations and hot springs contain either H 2 S or SO 2 , but in other cases large amounts of both gases are present (Sicardi 1956, Iwasaki et al 1962, Oana 1962, Symonds et al 1992.…”