USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly within the summit crater of Great Sitkin Volcano. Seismic activity remains very low, with only a few small rockfalls detected over the past day. No unusual activity was observed in mostly cloudy satellite views.

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 activity remains elevated, with numerous small earthquakes and intermittent episodes of volcanic tremor detected beneath the volcano. Minor steaming from the summit vent was observed in web camera images over the past day. 

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. 

Activity Summary:

The Halemaʻumaʻu eruption of Kīlauea is paused. Episode 42 ended February 15 at 11:38 p.m. HST. In the last 24 hours, continuous inflation of the summit has been observed. The modeled forecast window for the onset of episode 43 lava fountaining is March 10-14.

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

A recap of episode 42 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:

Continuous strong glow was observed at the north vent while more intermittent, weak glow was visible at the south vent in webcams overnight. Both the north and south vents also exhibited periods of minor spatter with glow at the south vent increasing in the early morning. Both vents are emitting steady gas plumes. Continuous low level seismic tremor was observed over the last 24 hours. There were six small earthquakes located in the summit region in the last 24 hours with the largest being a magnitude 1.1 this morning.

Inflation resumed yesterday around noon and has continued through this morning. As of this morning, the UWD tiltmeter has recorded 29.2 microradians of inflationary tilt since the end of episode 42, with about 1.3 microradians of net inflation over the past 24 hours.

Sulfur dioxide (SO₂) emission rates from the summit have typically averaged 1000-1500 t/d during eruptive pauses. Webcams show the plume blowing southwest this morning in moderate trade winds.
 

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:

The initial rapid rebound of tilt and glow from both vents indicate that another fountaining episode is likely. The overall inflationary trend has been interrupted by periods of no inflation or slight deflation recorded across all four summit tiltmeters that may impact the onset of episode 43 fountaining. Periods of weak deflation or no inflation have not been common in the early stages of repose between fountaining episodes. These changes in tilt rate are not predictable and create uncertainty in modeling the onset of episode 43 fountaining. Models indicate the forecast window for the start of episode 43 fountaining is likely between March 10 and March 14. The forecast window may change if inflation is interrupted by additional periods of deflation.

Kīlauea has been erupting episodically since December 23, 2024, primarily from two vents (north and south) in Halema‘uma‘u. Eruptive episodes, which generally last for less than 12 hours, are separated by pauses that can be as long as over 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 41:

A recap of episode 42 can be found in this Status Report.

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
• Note: The V3 camera is experiencing data issues and we have ordered a new camera to replace it following episode 42.
• 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.