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ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Thursday, April 15, 2021, 9:53 AM AKDT (Thursday, April 15, 2021, 17:53 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

No new explosions were detected in regional infrasound sensors and cloudy satellite images had no signs of significant volcanic emissions. Recent small ash plumes detected in satellite images did not have any associated infrasound detections, so it is possible that low-level activity may occur undetected during cloudy conditions. Sulfur dioxide emissions continue to be detected which is consistent with low-level eruptive activity.

Semisopochnoi is monitored by satellite data, 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.


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

No significant activity was observed in seismic, satellite or web camera data over the past day.

Eruptive activity at Veniaminof usually consists of minor ash emissions, lava fountaining and lava flows from the small cone in the summit caldera. Ash emissions are typically confined to the summit crater, but larger events can result in ash fall in nearby communities and drifting airborne ash.

The partial restoration of local seismic data will help the Alaska Volcano Observatory to detect changes in unrest that may lead to a more significant explosive eruption. AVO combines seismic, infrasound, lightning, web camera, and satellite data for rapid detection of such events.


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 significant activity was observed in partly cloudy satellite and web camera data over the past day. The local geophysical network is down so no seismic or infrasound data are available for the past day. AVO is working to recover the network.

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.

When operational, Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to precisely locate earthquakes and 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:

Aaron Wech, Acting Scientist-in-Charge, USGS
awech@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@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.