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U.S. Geological Survey
Sunday, August 27, 2017, 1:33 PM AKDT (Sunday, August 27, 2017, 21:33 UTC)

53°55'38" N 168°2'4" W, Summit Elevation 492 ft (150 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Unrest continues at Bogoslof volcano. A short-lived eruption began at 00:29 UTC on August 27 (16:29 AKDT on August 26) and lasted about 4 minutes producing an eruption cloud to about 27,000 feet above sea level that drifted southeast passing over southern Unalaska Island. This eruption was observed in seismic, infrasound and satellite data and one lightning stroke was detected. Elevated surface temperatures persist at the volcano since the eruption yesterday and may indicate that a lava dome is still present within the crater lake. No unusual seismicity or airwave signals in infrasound data have been detected since the eruption yesterday.

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. A Temporary Flight Restriction (TFR) remains in effect over the volcano. Please see for the status of the TFR.

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.

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 continues at Cleveland Volcano. Persistent elevated surface temperatures have been observed in cloudy satellite imagery over the past 24 hours. Clouds obscured views of the volcano by web camera. Elevated surface temperatures may indicate that a new lava dome is being emplaced within summit crater following the brief explosion last week (August 22) that destroyed the previous crater lava dome. No unusual seismicity or airwave signals in infrasound data have been detected over the past day.

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.

55°25'2" N 161°53'37" W, Summit Elevation 8261 ft (2518 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

No significant activity has been detected in seismic or infrasound data over the past 24 hours. No unusual activity has been observed in mostly cloudy satellite images over the past day and web camera images are currently not available.

The level of unrest at Pavlof can change quickly and the progression to eruptive activity can occur with little or no warning. We continue to monitor Pavlof closely and will provide any new information about the status of the volcano when or if it becomes available.


Information on all Alaska volcanoes is available at :

For definitions of Aviation Color Codes and Volcano Alert Levels, see:





Michelle Coombs, Scientist-in-Charge, USGS (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI (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.