ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Tuesday, November 21, 2017, 12:19 PM AKST (Tuesday, November 21, 2017, 21:19 UTC)
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 is likely continuing. Nothing significant was observed in cloudy to partly cloudy satellite images over the past day. Nothing noteworthy was detected in seismic or infrasound data from sensors located on neighboring islands.
Volcanic explosions producing high-altitude (>15,000 ft asl) volcanic clouds remain possible with little or no warning. 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 minor 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 World Wide Lightning Location Network.
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 is continuing at a low level. Nothing significant was observed in cloudy to partly cloudy satellite images over the past day. No activity was detected by seismic or infrasound sensors during the past 24 hours.
Lava effusion is typically confined to the summit crater at Cleveland, with the last significant lava flow (that extended to the ocean) occurring in 2001. The 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 have occurred.
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.
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
email@example.com (907) 786-7497
Jeff Freymueller, Coordinating Scientist, UAFGI
firstname.lastname@example.org (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.