ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, August 19, 2020, 11:48 AM AKDT (Wednesday, August 19, 2020, 19:48 UTC)

MAKUSHIN VOLCANO (VNUM #311310)
53°53'24" N 166°55'30" W, Summit Elevation 5906 ft (1800 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Small local earthquakes were detected over the past day. No surface activity was observed in satellite and web camera images.

The earthquake sequence may be associated with volcanic unrest, but there have been no signs of deformation or surface activity noted in other monitoring data. It is likely that we would see additional signs of unrest prior to an eruption, should it occur. The volcano is monitored with a network of seismic and GPS instruments, a web camera, satellite data, and regional infrasound and lightning detection instruments.

If an eruption were to occur, the main hazard would likely be from airborne ash and ash fall. Wind trajectory plots and hypothetical ash fall model information is available at https://www.avo.alaska.edu/activity/Makushin.php These models are updated twice per day in a hypothetical mode and will be updated immediately if there is an eruption. Seismic data, web camera images, and information products are also available at this site.

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

Small local earthquakes detected over the past day. No activity was observed in satellite and web camera images.

Great Sitkin volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.

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

No notable seismicity was noted in the past 24 hours, and no activity was observed in clear satellite and web camera imagery.

Veniaminof volcano is monitored with a local real-time seismic network, which will typically allows AVO to detect changes in unrest that may lead to a more significant explosive eruption. AVO combines seismic, infrasound, lightning, and satellite data for rapid detection of such events.

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

No notable seismicity was noted in the past 24 hours, and no activity was observed in cloudy satellite imagery.

Semisopochnoi is monitored by local seismic sensors, satellite data, and regional infrasound and lightning detection instruments. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.

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

No activity was observed in satellite images over the past 24 hours. The local seismic, infrasound and web camera network on the flanks of the volcano stopped transmitting data on 10 August. AVO network engineers continue to investigate the outage and there is no estimate of when the data flow will be restored.

Episodes of lava effusion and explosions can occur without advance warning. Explosions from Cleveland are normally short duration and only present a hazard to aviation in the immediate vicinity of the volcano. Larger explosions that present a more widespread hazard to aviation are possible, but are less likely and occur less frequently.

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

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

Taryn Lopez, Acting Coordinating Scientist, UAFGI
tmlopez@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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