Generation of pyroclastic flows and surges by hot-rock avalanches from the dome of Mount St. Helens volcano, USA

Bulletin of Volcanology
By: , and 

Links

Abstract

Several hot-rock avalanches have occurred during the growth of the composite dome of Mount St. Helens, Washington between 1980 and 1987. One of these occurred on 9 May 1986 and produced a fan-shaped avalanche deposit of juvenile dacite debris together with a more extensive pyroclastic-flow deposit. Laterally thinning deposits and abrasion and baking of wooden and plastic objects show that a hot ash-cloud surge swept beyond the limits of the pyroclastic flow. Plumes that rose 2-3 km above the dome and vitric ash that fell downwind of the volcano were also effects of this event, but no explosion occurred. All the facies observed originated from a single avalanche. Erosion and melting of craterfloor snow by the hot debris caused debris flows in the crater, and a small flood that carried juvenile and other clasts north of the crater. A second, broadly similar event occurred in October 1986. Larger events of this nature could present a significant volcanic hazard. ?? 1988 Springer-Verlag.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Generation of pyroclastic flows and surges by hot-rock avalanches from the dome of Mount St. Helens volcano, USA
Series title Bulletin of Volcanology
DOI 10.1007/BF01047505
Volume 50
Issue 1
Year Published 1988
Language English
Publisher Springer-Verlag
Description 12 p.
First page 14
Last page 25