Yellowstone Rated 'High Threat' For Volcanic Eruption
4utah.com
LAST UPDATE: 5/6/2005 6:12:25 PM
The Yellowstone caldera has been classified a high threat for volcanic
eruption, according to a report from the U.S. Geological Survey.
Yellowstone ranks 21st most dangerous of the 169 volcano centers in the
United States, according to the Geological Survey's first-ever comprehensive
review of the nation's volcanoes.
Kilauea in Hawaii received the highest
overall threat score followed by Mount St. Helens and Mount Rainer in
Washington, Mount Hood in Oregon and Mount Shasta in California.
Kilauea
has been erupting since 1983. Mount St. Helens, which erupted catastrophically
in 1980, began venting again in 2004.
Those volcanoes fall within the
very high threat group, which includes 18 systems. Yellowstone is classified
with 36 others as high threat.
Recurring earthquake swarms, swelling and
falling ground, and changes in hydrothermal features are cited in the report as
evidence of unrest at Yellowstone.
The report calls for better
monitoring of the 55 volcanoes in the very high and high threat categories to
track seismic activity, ground bulging, gas emissions and hydrologic changes.
University of Utah geology professor Robert Smith, who monitors
earthquakes and volcanic activity in Yellowstone, said more real-time monitoring
should be helpful.
"We've really been stressing over the last couple of
years that the USGS should consider hazards as a very high priority in their
future," he said. "We need to get the public's confidence and the perception
that we're doing it right."
The university has joined the Geological
Survey and Yellowstone National Park in creating the Yellowstone Volcano
Observatory, which uses ground-based instruments throughout the region and
satellite data to monitor volcanic and earthquake unrest in the world's first
national park.
The USGS report recognizes Yellowstone as an unusual
hazard because of the millions of people who visit the park and walk amid
features created by North America's largest volcanic system, Smith said, a
status he has been advocating for years.
Smith does not paint the
devastating picture portrayed in a recent TV docudrama but said smaller threats
exist. For example, a lower-scale hydrothermal blast could scald tourists
strolling along boardwalks.
Emissions of toxic gases from the park's
geothermal features also pose a threat. Five bison dropped dead last year after
inhaling poisonous gases trapped near the ground due to cold, calm weather near
Norris Geyser Basin.
Stepped up monitoring and a new 24-hour watch
office could lead to more timely warnings and help avoid human catastrophes at
Yellowstone and nationally, according to the USGS.
Forty-five eruptions,
including 15 cases of notable volcanic unrest, have been documented at 33
volcanoes in the U.S. since 1980, according to the report, released April 29.
--
U.S. Geological Survey: http://www.usgs.gov
Volcano Threat Report: http://pubs.usgs.gov/of/2005/1164
Yellowstone Volcano Observatory:
http://volcanoes.usgs.gov/yvo/index.html
