ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, October 21, 2017, 10:11 AM AKDT (Saturday, October 21, 2017, 18:11 UTC)
52°49'20" N 169°56'42" W,
Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
Unrest at Cleveland volcano continues. No unusual activity was observed in partly cloudy views of the volcano by satellite and web camera today. No significant activity related to lava effusion observed in seismic data and no explosive activity detected in infrasound data over the past day.
Lava domes that have been erupted since 2001 have all been destroyed by explosive activity within weeks to months after lava effusion. These explosions typically produce relatively small volcanic ash clouds that dissipate within hours, however more significant ash emissions are possible. There is no way to predict how long this lava dome will grow, or when it might be destroyed by an explosion.
Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
53°55'38" N 168°2'4" W,
Summit Elevation 492 ft (150 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Low-level unrest at Bogoslof volcano continues. No activity was observed in mostly cloudy satellite views over the past day. No significant activity was detected in seismic or infrasound data from sensors located on neighboring islands over the past day.
Bogoslof volcano remains at a heightened state of unrest and in an unpredictable condition. Activity can escalate quickly with explosions producing high-altitude (>15,000 ft) volcanic clouds with little to no detectable precursory activity. Some previous explosions have been preceded by an increase in earthquake activity that allowed for short-term forecasts of imminent significant explosive activity. Although we are able to detect energetic explosive activity in real-time, there can be a lag of tens of minutes until we can characterize the magnitude of the event and the altitude of the volcanic cloud. With existing data sources, AVO may not detect low-level unrest, including explosive activity. Such low-level periods of unrest and possible explosions could pose hazards near the volcano.
AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor volcanic activity with satellite images, seismic and infrasound instruments on nearby islands, and lightning data from the Worldwide Lightning Location Network.
OTHER ALASKA VOLCANOES
Information on all Alaska volcanoes is available at : http://www.avo.alaska.edu.
For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php
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Michelle Coombs, Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Jessica Larsen, Acting Coordinating Scientist, UAF
email@example.com (907) 322-4085
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.