ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, April 29, 2017, 11:55 AM AKDT (Saturday, April 29, 2017, 19:55 UTC)

BOGOSLOF VOLCANO (VNUM #311300)
53°55'38" N 168°2'4" W, Summit Elevation 492 ft (150 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

No significant volcanic activity was observed at Bogoslof volcano in seismic, infrasound data or satellite data over the past day.

Bogoslof volcano remains at a heightened state of unrest and in an unpredictable condition. Activity may ramp back up with additional explosions producing high-altitude (>15,000 ft) volcanic clouds with little 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 is typically a lag of tens of minutes until we can characterize the magnitude of the event and the altitude of the volcanic cloud. It is possible for low-level unrest, including explosive activity, to occur that we are unable to detect with existing data sources. Such low-level periods of unrest and possible explosions could pose a hazard in the immediate vicinity of the volcano.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, information from the Worldwide Lightning Location Network pertaining to volcanic-cloud lightning, and data from seismic and infrasound instruments on nearby islands for indications of volcanic activity.

Given the lack of a local monitoring network and the unpredictability of the volcano, activity at Bogoslof could increase again at any time. Thus, a Temporary Flight Restriction (TFR) remains in effect over the volcano for the time being. Please see http://tfr.faa.gov/tfr2/list.html for the status of the TFR.

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

The summit lava dome of Cleveland continues to slowly grow. Satellite data from yesterday indicates the dome has widened and grown vertically. Dome extrusion has occurred with little to no detectable seismicity. Slow dome growth with little to no seismicity is typical behavior at Cleveland as observed over the last several years of activity. No significant seismicity or infrasound data was observed 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.

OTHER ALASKA VOLCANOES

Information on all Alaska volcanoes is available at : http://www.avo.alaska.edu.

AVO scientists conduct daily checks of earthquake activity at all seismically-monitored volcanoes, examine web camera and satellite images for evidence of airborne ash and elevated surface temperatures, and consult other monitoring data as needed.

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:

Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085

aThe 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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