Tree-ring evidence for a two-year interval between recent prehistoric explosive eruptions of Mount St. Helens

Abstract

Research Article| August 01, 1985 Tree-ring evidence for a two-year interval between recent prehistoric explosive eruptions of Mount St. Helens David K. Yamaguchi David K. Yamaguchi 1College of Forest Resources, University of Washington, Seattle, Washington 98195 Search for other works by this author on: GSW Google Scholar Geology (1985) 13 (8): 554–557. https://doi.org/10.1130/0091-7613(1985)13<554:TEFATI>2.0.CO;2 Article history first online: 01 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 David K. Yamaguchi; Tree-ring evidence for a two-year interval between recent prehistoric explosive eruptions of Mount St. Helens. Geology 1985;; 13 (8): 554–557. doi: https://doi.org/10.1130/0091-7613(1985)13<554:TEFATI>2.0.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 Distinctive annual-ring patterns in trees in a forest stand 10 km east of Mount St. Helens indicate that the volcano's voluminous layer We tephra was erupted after the A.D. 1481 growth season, late in 1481, or early during 1482. Combined with earlier research that established A.D. 1480 as the date of eruption of the underlying, similar layer Wn tephra, the new tree-ring data provide evidence that these two major explosive tephra eruptions about 500 yr ago were separated by about 2 yr. During that eruptive sequence, a voluminous explosive eruption was therefore followed by more than 1 yr of minor explosive activity before another voluminous eruption occurred. This record suggests that Mount St. Helens might produce a second large explosive eruption during its current period of activity.Examinations of the tephra deposits that correlate with narrowring patterns in trees at Mount St. Helens also demonstrate that distinctive ring patterns can form in trees across a large range of tephra-layer thicknesses. The examinations also suggest that tephra coarseness interacts with tephra-layer thickness in determining the effects that tephra fallout will have upon forest trees. 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.