Eruptive activity continued this week at the active north crater of Mount Cerberus, now known as Mount Young. Minor ash deposits on the flanks of Mount Young were observed on fresh snow extending ~2 km (~1.2 miles) south-southwest of the active crater when web camera images were clear on January 1 and January 3. No ash plumes have been observed in web camera or satellite imagery, but a persistent steam plume rising up to 5,000 ft above sea level from the active crater may now be carrying minor volcanic ash within it. The observation of ash deposits this week was accompanied by periods of elevated seismicity and infrasound signals observed on the local geophysical network, which were likely due to weak explosive activity. Infrasound signals from the direction of Mount Young were observed at a regional array in Adak once during the last week.

The volcano has been erupting sporadically since 2018 and activity has been characterized by eruption of ash to heights usually less than 10,000 ft (3 km) above sea level. 

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

Earlier this week, the Don Young Recognition Act was signed into law. This Act renamed Mount Cerberus to Mount Young in honor of long-time Alaska Congressman Don Young. For more information, see: AVO News (alaska.edu).  

Lava continued to erupt within the summit crater of Great Sitkin Volcano this week. Weakly elevated surface temperatures were observed once in satellite data during the week, although most views of the summit were obscured by clouds. A high-resolution satellite image from Monday showed continued slow growth of the lava flow field. The active lava is currently advancing primarily to the south, over earlier 2021–2022 lava, and east into the remaining summit crater icefield. A small swarm of earthquakes occurred 6 km (4 mi) east of the summit and at depths less than 6 km (4 mi) on Monday and Tuesday, including earthquakes with magnitudes of 2.3 and 1.5. Besides this brief swarm, overall seismicity was low.

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

Seismicity remains above background levels and is characterized by weak, low-frequency earthquakes. No eruptive activity was observed over the past week and no explosions have been detected since December 7, 2022. Weakly elevated surface temperatures and minor steaming from the active vent were observed in satellite data and web camera views several times during the week and may be related to the cooling of lava around the vent.

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 regional infrasound and lightning networks. 

The ongoing earthquake swarm near Takawangha volcano continued over the past week, although seismic data from the local network experienced an outage over the past day which was resolved this morning. AVO analysts located 17 small earthquakes (less than magnitude 1.5) during the last 7 days. All of them occurred at with depths less than 6 miles (9 km) below sea level. Nothing significant was observed in satellite data this week, including some mostly clear and partly cloudy views. 

Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.

Due to a reduction of volcanic unrest at Cleveland Volcano over the past few months, on Thursday Alaska Volcano Observatory downgraded the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED.

Elevated surface temperatures and sulfur dioxide emissions had prompted AVO to raise the Aviation Color Code and Volcano Alert Level from UNASSIGNED/UNASSIGNED to YELLOW/ADVISORY on May 11, 2022. That activity continued throughout the summer, but all signs of unrest ceased or declined in recent months. Elevated surface temperatures in the summit crater are occasionally being observed but at reduced frequency and strength. Sulfur dioxide emissions have not been detected in satellite data since July 29, 2022. Minor steaming from the summit crater was observed over the past week but is considered to represent background activity for Cleveland. The last eruptive activity at Cleveland volcano was a short-lived explosion on the evening (local time) of June 1, 2020.

Despite the current pause, the eruptive period at Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These occur without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.  

When operational, Cleveland volcano is monitored by only three 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.