USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly within the summit crater of Great Sitkin Volcano. Seismic activity was elevated with small earthquakes and numerous rockfalls detected over the past day. A high resolution satellite image shows active dome growth to the south side of the summit crater.

The current lava eruption began in July 2021 and, since then, has filled most of the summit crater and advanced into 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, webcams, and regional infrasound and lightning networks.

Unrest continues at Shishaldin Volcano. Seismic and infrasound activity remains elevated, with numerous small earthquakes, seismic tremor, and infrasound detections observed over the past day.  A small steam plume was seen in clear webcam imagery. Satellite images detected sulfur dioxide with this plume drifting to the south.

Local seismic and infrasound sensors, web cameras, and a geodetic network are used to monitor Shishaldin Volcano. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lightning data, and satellite images to detect eruptions. 

Low-level unrest continues at the Atka volcanic complex with weak tremor and numerous small earthquakes observed in seismic data. Elevated water temperatures can be seen from the Korovin Volcano crater lake in clear satellite images. A plume of sulfur dioxide (SO2) gas was seen in satellite data drifting west and north from the volcano. 

The Atka volcanic complex includes several vents, including Korovin Volcano, Mount Kliuchef and Sarichef Volcano. Korovin has been the site of most historical eruptions that typically produce minor amounts of ash and occasional but small lava flows. The Atka volcanic complex is monitored by local seismic and infrasound sensors and webcam, satellite data, and regional lightning detection instruments.

Activity Summary:

The Halemaʻumaʻu eruption of Kīlauea is paused. The summit is currently inflating slowly; overnight, occasional glow was visible from the south and north vents and gas-pistoning continues. Rare spatter was visible at the south vent last night from the V3cam. The forecast window is now April 5-15 based upon modeling of the continued slow re-inflation of the summit.

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

HVO’s monitoring network is gradually recovering from power and storm related outages.  The Uēkahuna (UWD) tiltmeter is back online, however, no data was recovered from during the outage, so an offset was applied using data from other summit tiltmeters.  Several summit stations, including the SDH tiltmeter, will remain offline until we are able to re-establish access across the deep tephra field south of the caldera.

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

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 and north vents, along with rare spatter at the south vent. Spattering was seen within the south vent during an overflight yesterday as well. Currently, both vents are emitting gas plumes.

Seismic tremor continues and is punctuated by tremor bursts at intervals of 5–10 minutes. These bursts correlate with glow on the V3 camera and peak temperatures recorded by the F1 thermal camera at the south vent, consistent with ongoing gas-pistoning within the vents. One earthquake was recorded at the summit during the past day.

Summit tiltmeters IKI and SMC continue to record slow inflation since the end of episode 43. UWD tiltmeter is back online and is also recording slow inflation at the summit. The UWD tiltmeter has recorded an estimated 15.3 microradians of tilt since the end of episode 43, an increase of 0.7 microradians in the last 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 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. The continued slow inflation has pushed the forecast window back slightly with models indicating that episode 44 fountains are likely to start between April 5 and April 15. As the summit monitoring network continues to recover and data becomes more consistent, the forecast window should become better defined.

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 on March 10 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.