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SO2 gas emission rates of Mount St. Helens, 1980-1988

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Graph of sulufr dioxide emission rate of Mount St. Helens volcano, 1980-1988
View of gas plume emitted by Mount St. Helens from inside an airplane during a COSPEC flight
Strong west wind blows gas plume away from Mount St. Helens volcano in Washington.
Graph showing average daily emission rates of SO2 gas from Mount St. Helens during the period of airborne measurements from 25 May 1980 to 6 September 1988. More than 1,000 COSPEC flights were made during periods of non-explosive activity. Monthly averaging of the data above gives a total non-explosive SO2 emission after the 18 May 1980 eruption of nearly 0.5 million metric tons. Scientists interpret the steep drop in SO2 emission rates after 1980 as resulting from a decreased rate of magma supply to the surface of the volcano.

For data, see Open-File Report 94-212.

Annual emission rates, Mount St. Helens 1980-1988
Year
kilotons (metric)
1980 222
1981 105
1982 45
1983 39
1984 26
1985 13
1986 17
1987 3.5
1988 2.5
An estimated 1.5 million metric tons of sulfur dioxide gas was discharged by Mount St. Helens during the explosive eruption of 18 May 1980. Thus, approximately 2 million metric tons of sulfur dioxide was released during the whole eruption sequence.

References

McGee, K.A., 1992, The structure, dynamics, and chemical composition of noneruptive plumes from Mount St. Helens, 1980-88: Journal of Volcanology and Geothermal Research, v. 51, p. 269-282.

Gerlach, T.M., and McGee, K.A., 1994, Total sulfur dioxide emissions and pre-eruption vapor-saturated magma at Mount St. Helens, 1980-88: Geophysical Research Letters, v. 21, no. 25, p. 2833-2836.

Methods of monitoring volcanic gases

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Last modification: Tuesday, 18-Jul-2000 16:52:39 EDT (SRB)