USGS/Cascades Volcano Observatory, Vancouver, Washington
REPORT:
Potential Hazards from Future Eruptions of Mount St. Helens Volcano, Washington
--
Dwight R. Crandell and Donal R. Mullineaux, 1978,
Potential Hazards from Future Eruptions of Mount St. Helens Volcano, Washington:
U.S. Geological Survey Bulletin 1383-C, 26p.
Abstract
Mount St. Helens has been more active and more explosive during the last 4,500
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 2,500 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 the phenomena and
their threat to people and property; the accompanying 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-degree 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 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.
Return to:
[Report Menu] ...
URL for CVO HomePage is:
<http://vulcan.wr.usgs.gov/home.html>
URL for this page is:
<http://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/Bulletin1383-C/abstract.html>
If you have questions or comments please contact:
<GS-CVO-WEB@usgs.gov>
02/27/01, Lyn Topinka