ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Sunday, December 5, 2021, 1:32 PM AKST (Sunday, December 5, 2021, 22:32 UTC)

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

Seismicity remains above background levels. Elevated surface temperatures at the summit were observed in one partly cloudy satellite image over the past day. Other satellite and web camera views of the volcano obscured by clouds and nothing significant noted.

Lava effusion likely continues at a slow rate. It is possible that explosive activity could occur with little or no warning.

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


PAVLOF VOLCANO (VNUM #312030)
55°25'2" N 161°53'37" W, Summit Elevation 8261 ft (2518 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Unrest continues at Pavlof Volcano. Seismicity remains elevated and several explosions were detected by infrasound sensors over the past day. A diffuse ash cloud reaching as high as 10,000 feet above sea level and extending several tens of miles beyond the volcano was evident in web camera images and observed by a passing pilot. Minor ash emissions were also were observed intermittently in clear web camera images throughout the afternoon yesterday, but no ash emissions were observed in clear to partly cloudy satellite views of the volcano over the past day.

Small explosions accompanied by low-level ash emissions could happen at any time, and are typically a hazard in the immediate vicinity of the summit. The level of unrest at Pavlof can change quickly and the progression to more significant eruptive activity can occur with little or no warning.

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


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

Low-level eruptive activity continues at Semisopochnoi volcano. Seismic activity at the volcano remains elevated but at low-levels over the past day. Several explosions were recorded by infrasound sensors. Clouds have obscured the volcano and nothing was observed in satellite or web camera data over the past day.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft above sea level have characterized the recent activity. Small explosions and associated ash emissions may continue and could be difficult to detect, especially when thick cloud cover obscures the volcano.

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


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:

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

David Fee, Coordinating Scientist, UAF, 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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