USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly within the summit crater of Great Sitkin Volcano. Minor earthquakes were detected in the past day. Clouds obscured views of the volcano in both satellite and webcam views.

The current eruption began in July 2021. Since then, lava flows have 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, with minor seismic activity detected in the past day. Satellite and webcam views of the volcano were obscured by clouds, although an SO2 gas plume from the volcano was detected in satellite data.

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. 

Overview:

Intermittent eruptions of spatter bursts built a small cone around the north vent in Halemaʻumaʻu over the past day. Eruptive activity has slowed significantly since 6 a.m. HST. No precursory lava flows have erupted since September 12. Slow summit inflation stalled last night. While the level of summit inflation remains well above the fountaining episode 54 starting level, the lack of inflation will further delay the onset of episode 55 fountaining.  It is not possible to say how long the precursory activity may last.

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

Volcano Activity Notice (VAN) for the start of precursory eruptions: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-09-07T20:09:10+00:00

Summit Observations:

Intermittent spatter bursts became visible in the north vent early yesterday morning and increased in intensity throughout the day.  Around noon, the bursts began depositing spatter that built a small cone on the rim of the north vent. Initial bursts resembled splashing of fluid lava within the vent. As the afternoon progressed, eruptive activity cooled lava (making it more viscous or sticky) within the upper regions of the conduit. This change allowed gas to coalesce into larger and larger bubbles driving bigger bursts of spatter cooling the lave even more.  This produced a distinct Strombolian style of eruption throughout the night charactered by large individual spatter bursts one after another like fireworks, in contrast to the continuous eruption of lava in Hawaiian style lava fountains. Eruptions of spatter slowed this morning and there have been very few spatter bursts since 6 a.m. HST. Glow, flames and occasional spatter were also visible in the south and west vents overnight, and two small residual lava flows were visible oozing out lower on the north vent shield-structure overnight.

This is now the longest precursory period (6.8 days) since high fountains began after episode 4.  The longest period of precursory activity was 6.2 days before episode 44 and the most overflows record was 179 from the north and south vents combined prior to episode 36.

Weak spattering from the north vent was first reported at 6:54 p.m. HST on September 6. Sluggish precursory overflows from the north vent started at around 12:45 p.m. HST on September 7 with no dome fountains or spattering. Overflows from the north vent continued intermittently after that, with a total of 104 between September 7 and 12. Overflows lasted from a few minutes to about 2 hours long and were separated by interludes of about 15 minutes to 8 hours. Overflows between September 7-9 became progressively more vigorous and were fed by a dome fountain that reached 15-30 ft (5-10 m) tall. Two main lava flows formed during these overflows with one making it about a half mile (1 kilometer) to the southwest of the north vent, and the other making it less than half a mile (1 kilometer) to the northeast of the north vent. On September 10, overflows were generally sluggish, less frequent, shorter in duration (less than ten minutes), not fed by a dome fountain, and did not travel as far from the north vent. Overflows on September 11-12 showed more vigor and lasted longer than ten minutes, with dome fountains that grew from 15-30 ft (5-10 m) to 35-50 feet (10-15 m) tall and generated lava flows that traveled farther from the north vent than on September 10. Overflows from September 7-12 built a small shield around the north vent which has since been capped by a spatter cone built from strombolian activity over the past day. 

Tremor recorded at Kīlauea's summit has remained relatively uniform and continuous over the past 24 hours, possibly reflecting the stable position of magma close to the surface within all 3 vents. Tremor intensity did not vary appreciably with eruptive activity. Over the past 24 hours, 13 small earthquakes were recorded beneath the summit region mostly surrounding Halemaʻumaʻu. This includes a small swarm of earthquakes around 9:20 p.m. HST that lasted for about 10 minutes just north of the active vents. Similar numbers of earthquakes have occurred over the past  Recent earthquakes have not been closely clustered in space or time and are probably related to the general increase in pressure in the shallow Halemaʻumaʻu magma chamber.

Summit reinflation has been very unsteady since lava fountaining episode 54 on August 25. On September 7 around 3:00 p.m. HST, inflation at UWD reached a maximum that was higher than when episode 54 began, approximately 13.2 microradians. Following this inflationary high, UWD recorded around 1 microradian of deflation with the onset of precursory lava flows from the north vent. From then on, there was little net change until around 9 p.m. HST on September 10, when slow inflation returned. As of this morning, UWD is inflation remains stalled since stopping at about 9 p.m. HST. The total inflationary tilt measured on the UWD tiltmeter remains over two microradians above the 12.7 microradians lost during episode 54.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 and 5,000 tonnes per day. Ligh trade winds (less than 10 mph (5 meters per second) are pushing the degassing plume to the southwest of Kīlauea's summit caldera this morning are expected to continue.  Models indicate that gases as well as fine ash and Pele's hair would be transported to the south of Kaluapele if episode 55 fountaining were to begin today.

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, glow from the vents, overflows, inflation, and continued seismic tremor bursts at Kīlauea summit indicate that another lava fountaining episode could occur. Magma remains shallow in all of the vents, indicating that current conditions remain favorable for the onset of episode 55 fountaining. Additionally, the summit region has significantly exceeded the amount of deflation recorded during episode 54 and is several microradians over the level when that fountaining episode started. However, the stalling of inflation last night coupled with greatly reduced eruptive activity this morning indicates that the onset of episode 55 fountaining will be further delayed. There is currently no way to forecast when or if episode 55 fountains will start. It is likely that the dense, degassed magma produced by the vigorous strombolian eruptions last need will need to either be pushed out of the vent or be recycled into the underlying magma chamber before fountaining can start from the north vent.

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.