ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Monday, August 28, 2017, 1:09 PM AKDT (Monday, August 28, 2017, 21:09 UTC)

BOGOSLOF VOLCANO (VNUM #311300)
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. Three short-duration eruptive events occurred at Bogoslof over the past day. On August 27, at 23:08 UTC (15:08 AKDT) a brief explosive event lasting about 2 minutes occurred and produced a volcanic cloud that reached about 26,000 ft above sea level and drifted southeast. Another explosive eruption occurred at 11:23 UTC (03:23 AKDT) August 28 and lasted about 25 minutes. Satellite imagery showed only a very small eruption cloud drifting east-southeast. This volcanic cloud dissipated quickly. The third event of the past day occurred this morning at 19:17 UTC (11:17 AKDT) and produced a small volcanic cloud that reached as high as 25,000-30,000 feet above sea level before dissipating over the North Pacific Ocean. Since this event, seismicity and infrasound as detected on neighboring islands has been quiet and no lightning has been detected.

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 http://tfr.faa.gov/tfr2/list.html 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.

CLEVELAND VOLCANO (VNUM #311240)
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. Elevated surface temperatures have been observed in satellite data over the past day. A few clear web camera views of the summit this morning showed only a small vapor plume at the crater rim. Elevated surface temperatures may indicate that new lava is being emplaced within summit crater following the brief explosion last week (August 22) that removed the previous lava accumulation. 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.

PAVLOF VOLCANO (VNUM #312030)
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.

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

SUBSCRIBE TO VOLCANO ALERT MESSAGES by email: http://volcanoes.usgs.gov/vns/

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CONTACT INFORMATION:

Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (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.

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