ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, November 7, 2018, 12:03 PM AKST (Wednesday, November 7, 2018, 21:03 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. No eruptive activity was observed in partly cloudy satellite imagery. The satellite link that transmits seismic data from Semisopochnoi failed on November 1, but an infrasound array on Adak Island should still detect significant explosive emissions from Semisopochnoi (with a 13-minute delay) if atmospheric conditions permit. No such infrasound detections were recorded over the past day. Additional explosions are possible and will likely occur without warning.

Semisopochnoi is monitored with an on-island seismic network, though this is currently off-line, and remotely by satellite and lightning sensors. As noted above, 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

Veniaminof volcano continues to erupt, with minor lava spattering, effusion of a lava flow from the cone in the ice-filled summit caldera, and continuous, low-amplitude seismic tremor. Satellite views of the volcano over the past day showed elevated surface temperatures from the active lava effusion. Eruptive plume observations were obscured by clouds throughout most of the day, but webcam images in the afternoon (AKST) showed a low diffuse ash plume drifting toward the west. Trace ashfall is possible in nearby communities under favorable wind conditions.

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 a more significant explosive eruption. Rapid detection of such an event 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. Nothing significant has been detected in seismic or regional infrasound data over the past day. No activity was observed in cloudy to partly cloudy satellite images.

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. The web camera, one seismic station, and the local infrasound array are offline due to a equipment failure on September 23rd. This hampers efforts to rapidly detect explosive activity; however, Cleveland remains monitored with a single seismic station and regional instruments.

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. Seismicity remains above background levels with several small earthquakes detected over the past day. No activity was observed in satellite images or in regional infrasound data.

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.

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/

FOLLOW AVO ON FACEBOOK: https://facebook.com/alaska.avo

FOLLOW AVO ON TWITTER: https://twitter.com/alaska_avo

CONTACT INFORMATION:

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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavelizbekov@gmail.com (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.

---