Science Links Japan | 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.

Accession number;02A0337837

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

Author; KORZHINSKY M A (Inst. Experimental Mineralogy, Russian Acad. Sci., Chernogolovka, Rus) BOTCHARNIKOV R E (Inst. Experimental Mineralogy, Russian Acad. Sci., Chernogolovka, Rus) TKACHENKO S I (Inst. Experimental Mineralogy, Russian Acad. Sci., Chernogolovka, Rus) STEINBERG G S (Russian Acad. Natural Sci., Yuzhno-sakhalinsk, Rus)

Journal Title;Earth, Planets Space

Journal Code:G0106B

ISSN:1343-8832

VOL.54;NO.3;PAGE.337-347(2002)

Figure&Table&Reference;FIG.7, TBL.1, REF.30

Pub. Country;Japan

Language;English

Abstract;A high-temperature (up to 940.DEG.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.DEG.C., then gradually decreased with time and reached to 907.DEG.C. in 1999. Gas composition of the high-temperature fumarole became enriched in H2O and depleted in other gas components, in particular in CO2. 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 H2, CO2, and Stotal 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. (author abst.)

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