USGS/Cascades Volcano Observatory, Vancouver, Washington
REPORT:
Volcanic Event Notification at Mount St. Helens
-- Myers, Bobbie, and Theisen, George J., 1994,
Volcanic Event Notification at Mount St. Helens:
IN: Casadevall, Thomas J., (ed.), 1994,
Volcanic Ash and Aviation Safety:
Proceedings of the First International Symposium on Volcanic Ash and Aviation
Safety:
U.S. Geological Survey Bulletin 2047, 450p., p.207-212.
Abstract
During the 1980-86 eruptions of Mount St. Helens, hazards information was
quickly disseminated through a U.S. Geological Survey Cascades Volcano
Observatory - U.S. Forest Service notification system. Written and verbal
statements issued jointly by the Cascades Volcano Observatory (CVO) and
University of Washington were released to the Forest Service for telephone
call-down to governmental agencies and private interests. Once the call-down
was underway, public and media information tapes were updated and press
releases were issued. Because most of these eruptions had recognizable
precursors, a series of information statements and eruption forecasts was issued
during the weeks to hours before and eruption, thus providing advance warning of
volcanic activity and associated hazards.
Hundreds of small gas and ash emissions also occurred during 1980-86, most
without recognizable precursors. The lack of precursors made advance warning of
these events impossible; instead, information statements were issued after the
larger, more visible events. The occurrence of occasional small, unpredictable,
ash-producing explosions at Mount St. Helens during 1989-91, coupled with
increased concern about the hazards of volcanic ash to aviation, prompted CVO to
develop a seismic-alarm system that triggers on small volcanic events. This
alarm system activates CVO's 24-hour telephone beeper. In addition, the Federal
Aviation Administration (FAA) can also activate the CVO beeper to report
possible volcanic activity. These two modifications improve CVO's response time
for non-predictable, sudden-onset events and help the FAA quickly verify pilot
reports of possible volcanic plumes.
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06/20/02, Lyn Topinka