USGS Volcano Notice - DOI-USGS-HVO-2026-09-07T18:10:59+00:00

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused. Moderate to strong glow along with flames and weak, low spatter was visible from the north vent throughout the night, when not obscured by heavy rain and steam. Weak to strong glow was also observed from the west and south vents that occasionally disappeared during gas piston activity. Summit reinflation has been very irregular since lava fountaining episode 54 on August 25. The inflation that began on Saturday, September 5, continued until this morning but has stalled and leveled off starting around 6:30 am HST. A forecast window of September 7-10 is likely for the next episode if inflation resumes and follows the prior patterns.

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

A detailed summary of lava fountaining episode 54 on August 25, 2026 can be found below.

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

Summit Observations:

Overnight webcam views showed moderate to strong glow continuously from the Halemaʻumaʻu north vent, along with occasional flames and low-level spatter that got just above the rim of the north vent. Both the west vent and south vent showed weak to strong, periodic glow overnight that would come and go in association with gas piston activity. Last night was the first time that glow has been observed from the south vent since the end of episode 54.

Low level tremor continues across the summit with regular intervals (about 5 minutes) of gas pistoning returning at about 7:30 pm HST on Sunday night and continuing into this morning. Three small earthquakes were recorded beneath the summit region over the past 24 hours.

Summit reinflation has been very unsteady since lava fountaining episode 54 on August 25. On Saturday morning, tilt recorded on UWD began to increase and as of this morning had gained over 9 microradians on the UWD tiltmeter. Summit inflation recorded on UWD is now at the level prior to the 12.7 microradian deflation during lava fountaining episode 54. As of approximately 6:30 am HST this morning, summit tilt has leveled off and is nearly flat.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 and 5,000 tonnes per day. Trade winds are weak this morning and the degassing plume is being pushed towards public overlooks along the north and northeast rims of Kīlauea's summit caldera. South winds are expected to pick up later this morning and could blow volcanic gases as well as fine ash and Peleʻs hair if episode 55 starts, toward the north side of Kaluapele.

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:

The abrupt switch from summit deflation to inflation at the end of lava fountaining episode 54 and continued seismic tremor bursts from the Halemaʻumaʻu eruptive vents indicate that another lava fountaining episode may occur in the coming days. Reinflation has been slow and irregular, having been interrupted by multiple deflations of varying magnitude and duration. After inflating over 4 microradians from September 1-3, the summit deflated from Thursday to Friday (September 3-4) morning, after which it stalled for another day. Rapid summit inflation began around 10 a.m. HST on Saturday, September 5 and gained about 9 microradians in the past 2 days. Summit reinflation has now matched the 12.7 microradians lost during episode 54. Currently, summit tilt at UWD leveled off at around 6:30 am HST this morning and remains stalled. Should summit inflation resume soon, precursory eruptive activity would be expected later today or tomorrow. If tilt remains stalled for a longer period or if a prolonged deflation occurs, then the start of episode 54 could be delayed for several days.

The north vent continues to glow, and flames and low-level spatter were observed overnight. Additionally, the west vent and south vent were also observed glowing overnight. This indicates that magma is high within the vent conduits, however, no overflows have been observed from any of the vents yet. Episode 55 activity is likely to start today (Monday, September 7) if inflation resumes. If the inflation rate slows or if there are minor periods of stalling or deflation, the onset would be more likely on Tuesday or Wednesday, September 8 to 9. Should another significant deflation occur, it could push the forecast for the potential onset of episode 55 fountains back to Thursday to Sunday, September 10 to 13.

Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. Lava fountaining episodes, which generally last for less than 12 hours, are separated by pauses of two or more 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

Summary of episode 54:

A detailed account of episode 54 is given in the HVO Status Report issued on August 25: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-08-26T05:56:38+00:00

• Episode 54 of the ongoing Halemaʻumaʻu eruption began around 10:30 a.m. HST and ended at 7:33 p.m. HST on August 25, 2026, after 9 hours of continuous lava fountaining. 
• The maximum lava fountain height from the north vent was approximately 500 feet (150 meters) above ground level, reached between 12:15 p.m. and 1:00 p.m. HST. Neither the south vent nor the new west vent (formerly the collapse pit) fountained during this episode.
• The maximum plume height was approximately 17,000 feet (5,200 meters) above sea level.
• Most tephra fall was restricted to the closed area of Hawaiʻi Volcanoes National Park, southwest of the active eruptive vents in Halemaʻumaʻu. However, HVO did also receive a report of trace Pele’s hair falling in the Ka‘ū district of the Island of Hawaiʻi.

Resources:

NOTE: HVO’s monitoring network is mostly recovered from recent power- and storm-related outages. Several summit stations will remain offline as we continue working to repair instruments and re-establish connections in our monitoring network.

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 lava fountains and eruptive activity can be found here: https://www.usgs.gov/observatories/hvo/observatory-messages
• Three Kīlauea summit livestream cameras 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 eruptive 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.