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ALASKA VOLCANO OBSERVATORY
Information Release
Thursday, September 28, 2006 4:00 PM AKDT (0000 UTC)
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AVO ANNOUNCES A NEW ALERT-LEVEL SYSTEM FOR VOLCANIC ACTIVITY
As part of a national effort to adopt common terminology when describing
the state of unrest at U.S. volcanoes, AVO is implementing a new volcanic
alert-level system.
VOLCANIC-ALERT LEVELS
AVO will now rank the level of activity at Alaskan volcanoes using the
terms NORMAL, ADVISORY, WATCH, and WARNING.
These terms, defined below, are assigned based on observations,
instrumental monitoring data, and the known history and potential hazards
of each volcano.
Alert levels address the overall activity at the volcano, not just the
hazard to aviation. There may be situations where a volcano is producing
lava flows that are dangerous on the ground and merit a WATCH or WARNING,
however, the hazard to aviation is minimal.
Alert levels announcements will always contain additional explanation of
volcanic activity and expected hazards.
NORMAL
Typical background activity of a volcano in a non-eruptive state.
Or, after a change from a higher level:
Volcanic activity considered to have ceased, and volcano reverted to its
normal, non-eruptive state.
ADVISORY
Elevated unrest above known background activity.
Or, after a change from a higher level:
Volcanic activity has decreased significantly but continues to be closely
monitored for possible renewed increase.
WATCH
Volcano is exhibiting heightened or escalating unrest with increased
potential for eruptive activity.
Or:
A minor eruption is underway that poses limited hazards.
WARNING
Highly hazardous eruption underway or imminent.
LEVEL OF CONCERN COLOR CODES FOR AVIATION
AVO will continue to use the color-coded level of concern designation that
has been in place since 1990.
Colors will now reflect only the hazards posed to the aviation community.
Typically, this means that color codes indicate the likelihood or presence
of airborne ash and ash clouds that threaten aircraft. Definitions of each
color are below.
GREEN
Volcano is in a normal, non-eruptive state.
Or, after a change from a higher level:
Volcanic activity considered to have ceased and volcano reverted to its
normal, non-eruptive state.
YELLOW
Volcano is exhibiting signs of elevated unrest above known background
levels.
Or, after a change from a higher level:
Volcanic activity has decreased significantly but continues to be closely
monitored for possible renewed increase.
ORANGE
Volcano is exhibiting heightened unrest with increased likelihood of
eruption.
Or:
Volcanic eruption underway with no or minor ash emission.
RED
Eruption is forecast to be imminent with significant emission of ash into
the atmosphere likely
Or:
Eruption is underway with significant emission of ash into the atmosphere.
For more information and background on this new system, please see:
http://volcanoes.usgs.gov/2006/vhpalertlevel.pdf
VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478
CONTACT INFORMATION:
Tom Murray, Scientist-in-Charge, USGS
tlmurray@xxxxxxxx (907) 786-7497
Steve McNutt, Acting Coordinating Scientist, UAF
steve@xxxxxxxxxxxxxxxxx (907) 474-7131
The Alaska Volcano Observatory is a cooperative program of the U.S.
Geological Survey, the University of Alaska Fairbanks Geophysical
Institute, and the Alaska Division of Geological and Geophysical Surveys.
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