AVO Logo
Site Map | FAQ |
Alaska Volcano Observatory
Summary | Color Code Definitions | Webcams | Webicorders | RSAM | Activity Notifications | Notification Search | Great Sitkin | Cleveland | Pavlof | Semisopochnoi | Takawangha 
You are here: Home > Current Volcanic Activity

AVO VOLCANO ACTIVITY NOTIFICATION

ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, February 4, 2022, 1:29 PM AKST (Friday, February 4, 2022, 22:29 UTC)


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

The eruption of Pavlof Volcano continues. Lava effusion from the vent on the volcano’s upper southeast flank sent flows up to 1 km (0.6 miles) down the east flank of the volcano, with a new flow branch and strongly elevated surface temperatures observed in satellite data. Elevated seismicity, consisting of periods of sustained tremor, was detected throughout the week, but no explosions were detected.

Periods of lava fountaining from the vent on the volcano’s upper southeast flank have been occurring since mid-November 2021. This activity has built a small cone and sent flows down the flank that melt the snow and ice and produce variable amounts of meltwater. The meltwater typically incorporates loose debris on the flank of the volcano and forms thin (less than 2 m thick) lahars. The lahar deposits extend down the east-southeast flank for several kilometers, not quite to the base of the volcano.

Previous eruptions of Pavlof indicate that the level of unrest 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.


Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 592 mi (953 km) southwest of Anchorage. The volcano is about 4.4 mi (7 km) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft (15 km) above sea level have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 ft (12.2 km) above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, King Cove, is located 30 mi (48 km) to the southwest of Pavlof.

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

Lava effusion from a vent within the summit crater of Great Sitkin Volcano continues at a slow rate. The overall level of seismicity is very low. Weakly to moderately elevated surface temperatures consistent with lava effusion were detected in satellite data when the volcano was not obscured by cloud cover. Expansion of the lava flow field was observed in sporadic satellite views throughout the week, including advance of the southern, western, and northern flow lobes down the flanks of the volcano by up to 100 meters (328 feet).

Erupted lava has overtopped the summit crater rim and is flowing into small valleys on the south, west, and north flanks of the volcano. The terrain is steep in these areas, and blocks of lava could detach from the terminus of the flow lobes without warning and form small rock avalanches in these valleys. Such avalanches may liberate ash and gas and could travel several hundred meters beyond the lava flows; they would be hazardous to anyone in those areas.

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


Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 26 mi (43 km) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3 km-diameter summit crater. A steep-sided lava dome, emplaced during the most recent significant eruption in 1974, occupies the center of the crater. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft (7.6 km) above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.

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

The eruption at Semisopochnoi volcano continues. Seismicity remains elevated with continued periods of tremor and small earthquakes throughout the week. Minor explosions were recorded by local seismic and infrasound sensors on most days this week. Partly cloudy web camera and satellite views throughout the week showed persistent steaming and frequent small, local ash emissions.

Small explosions that produce minor ash deposits within the vicinity of the active north crater of Mount Cerberus, and ash clouds typically under 10,000 ft (3 km) above sea level have characterized the recent activity and show no signs of abating.

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


Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The volcano is dominated by a 5-mile (8 km) diameter caldera that contains a small lake and several post-caldera cones and craters. The age of the caldera is not known with certainty but is likely early Holocene. Prior to 2018, the previous known historical eruption of Semisopochnoi occurred in 1987, probably from Sugarloaf Peak on the south coast of the island, but details are lacking. Another prominent, young post-caldera landform is Mount Cerberus, a three-peaked cone cluster in the southwest part of the caldera. The island is uninhabited and part of the Alaska Maritime National Wildlife Refuge. It is located 40 mi (65 km) northeast of Amchitka Island and 130 mi (200 km) west of Adak.

DAVIDOF VOLCANO (VNUM #311040)
51°57'15" N 178°19'34" E, Summit Elevation 1076 ft (328 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

An earthquake swarm in the vicinity of Davidof volcano that began on Monday, January 24, has continued with small earthquakes detected every day this past week. The largest earthquake this week happened on January 29 at 1:34 AM AKST (09:34 UTC) and had a magnitude of 4.0. A similar earthquake swarm occurred in December 2021. No signs of unrest have been observed in partly cloudy satellite images of the volcano this week. This earthquake activity may be associated with volcanic unrest, or could be due to regional tectonic activity.

There is no real-time seismic monitoring network at Davidof volcano. The closest seismometers are approximately 9 miles (15 km) to the east of the volcano on Little Sitkin Island. Davidof is also monitored by satellite data and remote infrasound and lightning networks.


Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 218 miles (350 km) west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 1.5 mile (2.5 km) diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof.

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

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.
Contact AVO Privacy Accessibility Information Quality FOIA
URL: www.avo.alaska.edu/activity/report.php
Page modified: December 2, 2016 10:12
Contact Information: AVO Web Team

twitter @alaska_avo
facebook alaska.avo
email Receive volcano updates by email: USGS VNS

This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G22AC00137

Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.