| Abstract: | On May 25-26, May 30-June 2, and June 12-13, 1980, strong, high-altitude winds from the north occurred during periods of volcanic-ash eruption at Mount St. Helens in southwestern Washington. As a result, ash fell in the Bull Run watershed, Oregon, some 50 miles to the south, the principal water-supply source for the Portland area. Samples from precipitation collectors and from stream sites in the Bull Run watershed were collected on several dates during May and June 1980. Analyses were made and are tabulated for pH, conductivity, acidity, sulfate, and nitrate plus nitrite. Field pH values of the precipitation ranged from 4.0 to 5.6 pH units and the stream samples from 6.7 to 7.5 units. Particle-size analyses for ash samples collected in the Bull Run watershed and Portland, Oregon , are also shown. Volcanic events, precipitation and high-altitude speeds for northerly winds are given for May 18-June 15, 1980. (USGS) |
| Genre: | USGS Numbered Series |
| ProdID: | 15971 |
| Citation Author: | Shulters, Michael V.; Clifton, Daphne G. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | 11 p. :ill., map ;27 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 80-593 |
| Citation Search Results Text: | Mount St. Helens ash fall in the Bull Run watershed, Oregon, May-June 1980; 1980; OFR; 80-593; Shulters, Michael V.; Clifton, Daphne G. |
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| Citation Year: | 1980 |
| Type: | citation/reference |
| Text: | Mount St. Helens ash fall in the Bull Run watershed, Oregon, May-June 1980; 1980; OFR; 80-593; Shulters, Michael V.; Clifton, Daphne G. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
| Superseded by: |
http://pubs.er.usgs.gov/publication/cir850A
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