Decade-long study of degassing at Kudriavy volcano, Iturup, Kurile Islands (1990-1999): Gas temperature and composition variations, and occurrence of 1999 phreatic eruption

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概要

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• A high-temperature (up to 940°C) fumarolic activity at Kudriavy volcano had been studied during 1990-1999. The maximum gas temperatures of the fumaroles were measured in 1992 as 940°C, then gradually decreased with time and reached to 907°C in 1999. Gas composition of the high-temperature fumarole became enriched in H<SUB>2</SUB>O and depleted in other gas components, in particular in CO<SUB>2</SUB>. Hydrogen isotopic compositions of the high-temperature fumarolic gases were gradually depleted in deuterium. The gradual and continuous decrease in temperature and changes in gas composition observed during the last 10-year suggest that a magmatic melt have been degassing in a relatively steady-state manner from a single magma chamber. The detail investigations in 1998 and 1999 revealed short-term changes in gas composition characterized by sporadic increases in H<SUB>2</SUB>, CO<SUB>2</SUB>, and S<SUB>total</SUB> after intense precipitations. Small-scale eruptions occurred on October 7, 1999 at the summit. The ratios of major gas components (C/S, C/Cl, S/Cl, C/F, S/F, and Cl/F) significantly increased just prior to the eruption. The eruption at the Kudriavy volcano in 1999 was likely a phreatic eruption as a result of the intense precipitations after unusually long dry period. Meteoric water penetrated into the hot zone of volcano edifice and rapidly boiled causing the eruption.

• 公益社団法人 日本地震学会、地球電磁気・地球惑星圏学会 、特定非営利活動法人 日本火山学会、日本測地学会、日本惑星科学会の論文

著者

• Steinberg Genrikh

  Institute Of Volcanology And Geodynamics Russian Academy Of Natural Sciences

• Tkachenko Sergey

  Institute Of Experimental Mineralogy Russian Academy Of Sciences

• Korzhinsky Mikhail

  Institute Of Experimental Mineralogy Russian Academy Of Sciences

• Botcharnikov Roman

  Institute Of Experimental Mineralogy Russian Academy Of Sciences

関連論文

• Tyatya Volcano, southwestern Kuril arc : Recent eruptive activity inferred from widespread tephra
• Decade-long study of degassing at Kudriavy volcano, Iturup, Kurile Islands (1990-1999) : Gas temperature and composition variations, and occurrence of 1999 phreatic eruption
• Decade-long study of degassing at Kudriavy volcano, Iturup, Kurile Islands (1990-1999): Gas temperature and composition variations, and occurrence of 1999 phreatic eruption

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