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AVO VOLCANO ACTIVITY NOTIFICATION

ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Tuesday, September 18, 2018, 11:55 AM AKDT (Tuesday, September 18, 2018, 19:55 UTC)


SEMISOPOCHNOI VOLCANO (VNUM #311060)
51°55'44" N 179°35'52" E, Summit Elevation 2625 ft (800 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Unrest continues at Semisopochnoi volcano. Seismicity remains elevated with nearly constant tremor being recorded by local sensors. No volcanic activity was observed in cloudy satellite data over the past day, and no activity has been detected in regional infrasound data.

Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.


VENIAMINOF VOLCANO (VNUM #312070)
56°11'52" N 159°23'35" W, Summit Elevation 8225 ft (2507 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Eruption of a lava flow from Veniaminof volcano's summit cone likely continues, as suggested by continued observations of elevated seismic activity and elevated surface temperatures in thermal satellite data. Incandescence was not observed in nighttime webcam images, but views were likely obscured by clouds. No significant ash emissions have been observed.

Veniaminof Volcano is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.


GREAT SITKIN VOLCANO (VNUM #311120)
52°4'35" N 176°6'39" W, Summit Elevation 5709 ft (1740 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Low-level unrest continues at Great Sitkin Volcano. Earthquake activity remains elevated. Tremor activity was recorded in seismic data at 03:05 AKDT September 18 (11:05 UTC). The event is similar to previous tremor bursts that have occurred over the past few months at Great Sitkin, one of which resulted from a phreatic explosion that produced a small ash deposit near the summit on June 10. Nothing significant was observed in regional infrasound data or cloudy satellite images during the last 24 hours.

Great Sitkin Volcano is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.


CLEVELAND VOLCANO (VNUM #311240)
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Low-level unrest continues at Cleveland Volcano. Elevated surface temperatures were observed in satellite images, and clear webcam views also show a small steam plume over the past day. No significant activity has been detected in seismic or infrasound data.

Cleveland volcano is monitored by only two seismic stations, which restricts 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.

For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php

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CONTACT INFORMATION:

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

David Fee, Coordinating Scientist, UAFGI
dfee1@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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