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U.S. Geological Survey
Monday, February 20, 2017, 8:15 PM AKST (Tuesday, February 21, 2017, 05:15 UTC)

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

A storm in the Unalaska area has impacted data communications at AVO's facility in Dutch Harbor. As of about 17:50 AKST this evening (02:50 February 21 UTC), all seismic and infrasound data from the Okmok and Makushin networks ceased transmission. This limits our ability to forecast and detect eruptions from Bogoslof. It is possible that data transmission could resume again within a few hours. In addition, the area is currently covered by thick weather clouds to as high as 30,000 ft asl, further limiting our ability to observe volcanic activity.

In the meantime, AVO uses lightning data, and infrasound data from distant stations, to detect explosive eruptive activity. Some but not all of the eruptions from Bogoslof in the current sequence have produced detectable lightning strokes. Detected lightning provides near-real-time confirmation of explosive activity. Infrasound data from distant stations can also confirm explosive activity, but detection at these distant stations is delayed by tens of minutes.

The last explosive eruption from Bogoslof was yesterday at about 17:08 AKST, and the volcano remains at a heightened state of unrest and in an unpredictable condition. Additional explosions producing high-altitude volcanic clouds could occur at any time. Low-level explosive activity that is below our ability to detect in our data sources may be occurring. These low-level explosions could pose a hazard in the immediate vicinity of the volcano.

The Aviation Color Code remains at RED and the Alert Level remains at WARNING.

Status of ash-cloud forecasts can be found at the National Weather Service Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/


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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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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Page modified: December 2, 2016 10:12
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