| Abstract: | Small-magnitude earthquakes began beneath Mount St. Helens 40 days before the eruption of 20 March 1982. Unlike earlier preeruption seismicity for this volcano, which had been limited to shallow events (less than 3 kilometers), many of these earthquakes were deep (between 5 and 11 kilometers). The location of these preeruptive events at such depth indicates that a larger volume of the volcanic system was affected prior to the 20 March eruption than prior to any of the earlier dome-building eruptions. The depth-time relation between the deep earthquakes and the explosive onset of the eruption is compatible with the upward migration of magmatic gas released from a separate deep reservoir. |
| Genre: | Article |
| ProdID: | 70011396 |
| Citation Author: | Weaver, C. S.; Zollweg, J. E.; Malone, S. D. |
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| Citation End Page: | 1394 |
| Citation Issue: | 4618 |
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| Citation Language: | English |
| Citation Larger Work Title: | Science |
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| Citation Number Of Pages: | 4 |
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| Citation Search Results Text: | Deep earthquakes beneath Mount St. Helens: Evidence for magmatic gas transport?; 1983; Article; Journal; Science; Weaver, C. S.; Zollweg, J. E.; Malone, S. D. |
| Citation Start Page: | 1391 |
| Citation Volume: | 221 |
| Citation Year: | 1983 |
| Type: | citation/reference |
| Text: | Deep earthquakes beneath Mount St. Helens: Evidence for magmatic gas transport?; 1983; Article; Journal; Science; Weaver, C. S.; Zollweg, J. E.; Malone, S. D. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sat, 1 Jan 1983 00:00 -0600 |
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