ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Monday, July 10, 2017, 2:08 PM AKDT (Monday, July 10, 2017, 22:08 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

Two periods of eruptive activity have occurred over the past day at Bogoslof. The first consisted of a series of explosions that began on Sunday, 9 July at 23:47 AKDT (07:47 UTC July 10) and ended about 02:35 AKDT (10:35 UTC) July 10. AVO raised the Aviation Color Code/Volcano Alert Level to RED/WARNING in response to the activity. A small eruption cloud associated with the early portion of this eruption was evident in satellite data. The cloud may have reached as high as 20,000 ft. above sea level and was carried to the southeast but dissipated rapidly. Based on a decline in seismicity after about 03:00 AKDT (11:00 UTC) July 10, AVO lowered the Aviation Color Code/Volcano Alert Level to ORANGE/WATCH this morning. The second period of eruptive activity began later in the morning at 10:00 AKDT (18:00 UTC) and consisted of 8 minutes of elevated seismicity and infrasound from Bogoslof. In spite of the activity, no significant emissions from the volcano were detected in satellite images. As a result, the Aviation Color Code/Volcano Alert Level remained at ORANGE/WATCH.

Bogoslof volcano remains at a heightened state of unrest and in an unpredictable condition. Activity can escalate quickly with additional 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 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. A Temporary Flight Restriction (TFR) is in effect over the volcano at the present time. 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 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.

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

Nothing significant observed in mostly cloudy satellite images over the past day. Minor degassing seen in web camera views. No seismicity or infrasound detected.

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 unusual activity has been detected in seismic or infrasound data over the past 24 hours. Satellite images and web camera views were cloudy.

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:

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

Pavel Izbekov, Acting Coordinating Scientist, UAF
GIpavel@gi.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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