Emission of sulfur dioxide gas from Mount St. Helens, 1980-1988
Strong west wind blows gas plume away from Mount St. Helens volcano in
Washington.
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.
Average daily emission rates of SO2 gas from Mount
St. Helens volcano, 1980-1988
Graph showing average daily emission rates of SO
2 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
SO
2 emission after the 18 May 1980 eruption of nearly 0.5 million
metric tons. Scientists interpret the steep drop in SO
2
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.
Average yearly emission rates of SO2 gas from Mount St. Helens
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 |