Title: Influence of magma composition on the eruptive activity of Mount St. Helens, Washington
Abstract: Research Article| June 01, 1995 Influence of magma composition on the eruptive activity of Mount St. Helens, Washington James E. Gardner; James E. Gardner 1Institut de Physique du Globe, 4 place Jussieu, 75252 Paris cédex 05, France Search for other works by this author on: GSW Google Scholar Steve Carey; Steve Carey 2Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 02881 Search for other works by this author on: GSW Google Scholar Haraldur Sigurdsson; Haraldur Sigurdsson 2Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 02881 Search for other works by this author on: GSW Google Scholar Malcolm J. Rutherford Malcolm J. Rutherford 3Department of Geological Sciences, Brown University, Providence, Rhode Island 02912 Search for other works by this author on: GSW Google Scholar Geology (1995) 23 (6): 523–526. https://doi.org/10.1130/0091-7613(1995)023<0523:IOMCOT>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation James E. Gardner, Steve Carey, Haraldur Sigurdsson, Malcolm J. Rutherford; Influence of magma composition on the eruptive activity of Mount St. Helens, Washington. Geology 1995;; 23 (6): 523–526. doi: https://doi.org/10.1130/0091-7613(1995)023<0523:IOMCOT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The relation of eruptive intensity with magma composition and viscosity has been investigated for Mount St. Helens, Washington, where eruptive activity has ranged from basaltic lava flows to dacitic Plinian eruptions. The Plinian eruptions have varied in eruptive intensity from 106 to 108 kg/s, yet all erupted dacitic magma. These dacites, however, differ greatly in temperature, water content, and crystallinity, and thus magma viscosity varies by two orders of magnitude. The variation in viscosity is correlated inversely with intensity, demonstrating the control of composition on intensity. In addition, more mafic magmas erupted at lower intensities, showing that the wide range in eruptive behavior is linked to magma composition. Changes in composition result mainly from mixing of basaltic and dacitic magmas and occur in cycles. The rate of change during a cycle depends upon the length of the preceding repose period and the flux of basalt to the reservoir, because the supply of dacite has been relatively constant. When the flux of basalt is low, cycles progress from dacite to andesite over extended periods, whereas a higher flux leads to more rapid changes. Because composition controls eruptive intensity, the eruptive behavior of the volcano also varies through a cycle. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Publication Year: 1995
Publication Date: 1995-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 28
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