Potential hazards from future eruptions of Mount St. Helens volanco, Washington

Technical Report · Sun Jan 01 04:00:00 EST 1978

OSTI ID:5983013

Crandell, D R; Mullineaux, D R

Mount St. Helens has been more active and more explosive during the last 4500 years than any other volcano in the conterminous United States. Eruptions of that period repeatedly formed domes, large volumes of pumice, hot pyroclastic flows, and during the last 2500 years, lava flows. Some of this activity resulted in mudflows that extended tens of kilometers down the floors of valleys that head at the volcano. This report describes the nature of these phenomena and their threat to people and property; the accompaning maps show areas likely to be affected by future eruptions of Mount St. Helens. Explosive eruptions that produce large volumes of pumice affect large areas because winds can carry the lightweight material hundreds of kilometers from the volcano. Because of prevailing winds, the 180/sup 0/ sector east of the volcano will be affected most often and most severely by future eruptions of this kind. However, the pumice from any one eruption probably will fall in only a small part of that sector. Pyroclastic flows and mudflows also can affect areas far from the volcano, but the areas they affect are smaller because they follow valleys. Mudflows and possibly pyroclastic flows moving rapidly down Swift and Pine Creeks could displace water in Swift Reservoir, which could cause disastrous floods farther downvalley.

• Research Organization: Geological Survey, Washington, DC (USA)
• OSTI ID: 5983013
• Report Number(s): USGS-BULL-1383-C; ON: DE83902184
• Country of Publication: United States
• Language: English

Related Subjects

570000* -- Health & Safety
58 GEOSCIENCES
580202 -- Geophysics-- Volcanology-- (1980-1989)
99 GENERAL AND MISCELLANEOUS
CASCADE MOUNTAINS
ERUPTION
FEDERAL REGION X
FORECASTING
HAZARDS
MOUNTAINS
MT ST HELENS
NORTH AMERICA
USA
VOLCANISM
VOLCANOES
WASHINGTON