Differentation of magmatic emanation

Iwasaki, Iwaji; Ozawa, T.; Yoshida, Minoru; Katsura, Takashi; Iwasaki, Bunji; Kamada, M.

doi:10.1007/bf02597512

Cited by 14 publications

(18 citation statements)

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“…They can provide crucial information in understanding such subsurface processes, and therefore, they are considered useful tools for volcano monitoring. According to volcanic gas surveys of pioneering researchers, volcanic and/or fumarolic gas composition varies with outlet temperature, and there is a general trend that SO 2 is a dominant S-bearing gas for high outlet temperature, whereas H 2 S becomes dominant for low outlet temperature (e.g., Iwasaki et al 1966). For example, major degassing Japanese volcanoes that emit high-temperature magmatic gases usually have SO 2 /H 2 S molar ratio >6 (Shinohara 2013).…”

Section: Introductionmentioning

confidence: 99%

Volcanic plume measurements using a UAV for the 2014 Mt. Ontake eruption

et al. 2016

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A phreatic eruption of Mt. Ontake, Japan, started abruptly on September 27, 2014, and caused the worst volcanic calamity in recent 70 years in Japan. We conducted volcanic plume surveys using an electric multirotor unmanned aerial vehicle to elucidate the conditions of Mt. Ontake's plume, which is flowing over 3000 m altitude. A plume gas composition, sulfur dioxide flux and thermal image measurements and a particle sampling were carried out using the unmanned aerial vehicle for three field campaigns on November 20 and 21, 2014, and June 2, 2015. Together with the results of manned helicopter and aircraft observations, we revealed that the plume of Mt. Ontake was not directly emitted from the magma but was influenced by hydrothermal system, and observed SO 2 /H 2 S molar ratios were decreasing after the eruption. High SO 2 flux of >2000 t/d observed at least until 20 h after the onset of the eruption implies significant input of magmatic gas and the flux quickly decreased to about 130 t/d in 2 months. In contrast, H 2 S fluxes retrieved using SO 2 /H 2 S ratio and SO 2 flux showed significantly high level of 700-800 t/d, which continued at least between 2 weeks and 2 months after the eruption. This is a peculiar feature of the 2014 Mt. Ontake eruption. Considering the trends of the flux changes of SO 2 and H 2 S, we presume that majority of SO 2 and H 2 S are supplied, respectively, from high-temperature magmatic fluid of a deep origin and from hydrothermal system. From the point of view of SO 2 /H 2 S ratios and fumarolic temperatures, the plume degassing trend after the 2014 eruption is following the similar course as that after the 1979 eruptions, and we speculate the 2014 eruptive activity will cease slowly similar to the 1979 eruption.

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Section: Introductionmentioning

confidence: 99%

Volcanic plume measurements using a UAV for the 2014 Mt. Ontake eruption

et al. 2016

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“…FAIVRE-PIERRET et al (1980) also (1962, 1966 have concluded on the basis of the have described, in their study of. volcanic gases data observed in Japanese volcanic gases that at Etna Volcano, that SO2/HCl could be one of the composition of volcanic gases is much the parameters for estimating volcanic activity.…”

Section: Introductionmentioning

confidence: 89%

Relationship between volcanic activity and chemical composition of volcanic gases - A case study on the Sakurajima Volcano.

1982

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“…In some solfatara, SO 2 gas is predominant, and often accompanied by HCl gas (Iwasaki et al, 1966). The genetical problem on the relation of H 2 S and SO 2 gases in solfatara is unkown.…”

Section: Some Problems Related To Acid-sulfate Depositsmentioning

confidence: 99%

Mineralizations of Base Metal Deposits of Acid‐Sulfate Type Coexisting with Adularia‐Sericite Type

Imai¹

1999

Resource Geology

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: Two types of ores are recognized in the Huanzala mine, Peru. Zinc and lead ore of adularia‐sericite type, is accompanied by pyrite body and skarn. Orthoclase (adularia), sericite and calcite are found in the skarn and altered country rocks. On the other hand, copper and silver (tin) ore of acid‐sulfate type, is characterized by enargite, luzonite and bornite, accompanied by tin, silver and tellurium minerals. Although sericite and calcite are found only at the earlier stage in the mineralization of acid‐sulfate type, kaolinite appears in the country rocks at a subsequent stage. It is interpreted that the ore‐forming fluid of the acid‐sulfate type separated from the adularia‐sericite type by boiling in the early stage of mineralization. The separated fluid was nearly neutral just after boiling and changed into acidic by the oxidation of H2S into HSO4‐. Both types of mineralizations are studied in terms of fo2‐fs2‐pH‐temperature diagrams. The adularia‐sericite type might correspond to the hot‐water system of a geothermal area, and the acid‐sulfate type to the vapor‐dominated system. The copper ores from the Teine mine, Hokkaido, Japan and the Chinkuashih mine, Taiwan are acid‐sulfate type, characterized by the occurrence of enargite and luzonite. However, zinc and lead ores of the adularia‐sericite type are also present in these deposits. Both types in the Teine and Chinkuashih deposits are supposed to have formed in the similar relation as in the Huanzala deposits. The enargite and luzonite ores in the Hokuetsu mine, Japan are closely associated with native sulfur of solfataric origin.

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Differentation of magmatic emanation

Cited by 14 publications

References 0 publications

Volcanic plume measurements using a UAV for the 2014 Mt. Ontake eruption

Volcanic plume measurements using a UAV for the 2014 Mt. Ontake eruption

Relationship between volcanic activity and chemical composition of volcanic gases - A case study on the Sakurajima Volcano.

Mineralizations of Base Metal Deposits of Acid‐Sulfate Type Coexisting with Adularia‐Sericite Type

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