USGS Volcanoes: Notices released in the last day.

Lava continues to slowly erupt within the summit crater at Great Sitkin Volcano. Minor lava dome growth to the southwest and rockfalls down the south side of the dome were observed in rare clear satellite views. Elevated surface temperatures from the warm, active lava dome were also observed when conditions allowed. Seismic activity remains low, with the detection of occasional small volcanic earthquakes and seismic signals from small rockfalls within the crater.   

The current lava eruption began in July 2021 and has filled most of the summit crater and advanced into the valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic and infrasound sensors, satellite data, and web cameras, and regional infrasound and lightning networks.

Signs of volcanic unrest at Shishaldin Volcano continue. Seismic and infrasound activity remain elevated, with numerous small earthquakes, frequent infrasound signals, and volcanic tremor recorded throughout the week. Daytime web camera views and a high-resolution satellite view on March 19 showed minor steaming from the summit, and sulfur dioxide gas emissions were detected in satellite data all week.   

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, the Alaska Volcano Observatory uses nearby geophysical networks, regional infrasound and lightning data, and satellite data to monitor the volcano. 

Low-level unrest continued at Atka volcanic complex with weak-to-moderate volcanic tremor, and numerous small earthquakes detected in seismic data. Clear satellite views over the week showed weak-to-moderately elevated surface temperatures for the Korovin summit lake region. Sulfur dioxide gas emissions were also detected in satellite data all week. 

The Atka volcanic complex is monitored by local seismic and infrasound sensors and webcam, satellite data, and regional lightning detection instruments. 

Activity Update: All volcanoes in the Cascade Range of Oregon and Washington are at normal background activity levels. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State and Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake in Oregon.

Past Week Observations: During the past week, small earthquakes were detected at Mount St. Helens. All monitoring data are consistent with background activity levels in the Cascade Range.

Activity Summary:

The Halemaʻumaʻu eruption of Kīlauea is paused. The summit is currently inflating slowly, occasional glow was visible from the south vent and gas-pistoning continues. The preliminary forecast window for the onset of episode 44 lava fountaining is April 1 to April 10.

No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.

Power outages and storm effects continue to hamper our monitoring network.  Another storm is expected over the weekend and we expect issues to continue until it clears and power stabilizes on the island.

A summary of episode 43 can be found in this Status Report.

NOTE: The V2 camera went offline due to a power outage, the V1 camera remains damaged from episode 43.

Significant changes in activity between Daily Updates are posted here: https://www.usgs.gov/observatories/hvo/observatory-messages

Summit Observations:                                                                                                                       

Overnight, intermittent glow was observed at the south vent via the V3 webcam. Currently, both vents are quiet and emitting gas plumes, while abundant steam rises from cooling lava flows from episode 43 within Halemaʻumaʻu crater.

Seismic tremor has decreased overall, though tremor bursts persist at intervals of 5–10 minutes. These bursts correlate with peak temperatures recorded by the F1 thermal camera at the south vent, consistent with ongoing gas pistoning within the vent. Two earthquakes were recorded at the summit during the past day.

Summit tiltmeters UWD, SDH, and SMC continue to record slow inflation tha past few days.  UWD is currently offline but is estimated to have gained approximately 11.7 microradians of tilt since the end of episode 43 with an estimated gain of 0.1 microradians in the past 24 hours.  

During eruptive pauses, like the current conditions, the SO₂ emission rate from the summit has varied within a typical range of 1,000 to 5,000 tonnes of SO2 per day.

Rift Zone Observations:

Rates of seismicity and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone. SO₂ emissions from the East Rift Zone remain below the detection limit.

Analysis:

Rapid rebound of tilt following episode 43 fountaining, continued tremor, and visible glow from the vents suggest that another fountaining episode is likely. Summit inflation remains slow compared to other episodes of repose and is complicated by weather signals and loss of data during power outages. Preliminary models indicate that episode 44 fountains are likely to start between April 1 and April 10, but the forecast window may be pushed further back with additional data.

Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. Fountaining episodes, which generally last for less than 12 hours, are separated by pauses that can be longer than two weeks.

HVO continues to closely monitor Kīlauea and is in contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency about eruptive hazards.

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm

Recap of episode 43:

Episode 43 ended at 6:21 p.m. HST after fountaining for just over 9 hours from both vents and sending tephra into surrounding communities. A complete summary of activity can be found here. 

Resources:

The following links provide more information about the current eruption that began on December 23, 2024:

Eruption resources, including the most recent map and a timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information

Short messages tracking the evolution of the fountains and eruptive activity can be found here: https://www.usgs.gov/observatories/hvo/observatory-messages

Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://www.youtube.com/@usgs/streams

Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams

Volcano Watch article on gas pistons: https://www.usgs.gov/observatories/hvo/news/volcano-watch-so-what-earth-or-least-kilauea-a-gas-piston

Hazards:

This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park.

• Volcanic Gas: high levels of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continually released during an eruption. Emissions can remain locally hazardous in the areas immediately downwind of the vents, even when the vents are not actively erupting. SO2 reacts in the atmosphere to create vog (volcanic air pollution) downwind. SO2 and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/
• Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
• Lava flows: lava on the floor of Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera, remains hot and may slowly move in the days immediately following an eruptive episode.

Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. This underscores the extremely hazardous nature of Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.

NORTHERN MARIANAS VOLCANOES
No definitive signs of unrest were detected at any Northern Mariana Island volcanoes during the past week. 

Monitoring of Northern Mariana Islands Volcanoes

Northern Mariana Island volcanoes are monitored using seismo-acoustic sensors on Saipan, and by examining satellite imagery. We also use distant seismic stations in Guam and Chichijima, Japan, and hydroacoustic data from Wake Island, when available. 

This level of monitoring can detect significant volcanic activity in the CNMI but cannot provide advanced warning of eruptions.

Due to a lack of geophysical monitoring on any of the volcanic islands, the following volcanoes have alert levels of UNASSIGNED: Anatahan, Sarigan, Farallon de Pajaros, Supply Reef, Maug, Asuncion, Agrigan, Pagan, Almagan, and Guguan.