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. Steaming and elevated surface temperatures at the summit dome were observed in clear webcam and satellite views of the volcano.

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. Clear webcam views of the volcano showed the typical gas plume emanating from the summit of the volcano. The SO2 gas plume was also 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. 

Seismic activity at Kupreanof Volcano over the past day was very low. Weak steaming from fumaroles on the flank of the volcano was seen in clear webcam views. Because of the sharp drop in seismicity to very low levels over the past month, and the decrease in SO2 gas emissions, the volcano's Aviation Color Code and Volcano Alert Level were lowered to UNASSIGNED yesterday afternoon. The volcano was not lowered to GREEN and NORMAL because of insufficient coverage by ground-based monitoring data.

A new temporary monitoring station was installed recently near Mount Kupreanof and is providing seismic data, infrasound data, gas measurements, and web camera images on an intermittent basis. This is by design to conserve battery power, but the frequency of data acquisition can be increased if activity warrants. The closest functioning seismometers that provide continuous data are approximately 10 miles (16 km) to the northeast of the volcano as part of the Mount Veniaminof network. Mount Kupreanof is also monitored by satellite data, remote infrasound and lightning networks, and visual observations from pilots and mariners passing by the volcano.

[CORRECTED] The number of earthquakes, intensity of steam emissions, and measured sulfur dioxide emissions beneath Mount Kupreanof have declined. Due to these changes, the Alaska Volcano Observatory is lowering the Aviation Color Code and the Volcano Alert Level to UNASSIGNED. 

Summary of activity and hazards 

• Seismicity was first detected in February 2026 and increased over the following months, with earthquakes as large as magnitude 3.1 recorded. However, seismicity has declined over the past month.
• Sulfur dioxide (SO₂) emissions were detected beginning on April 4 with emission rates of ~100 to 1,000 tons per day, which are well above the background rate of <100 tons per day. These have dropped to background levels since late August.
• Collectively, these data likely indicate the magmatic intrusion beneath Mount Kupreanof has stalled.

Additional information: 

• The Aviation Color Code and the Volcano Alert Level are being changed to UNASSIGNED, rather than GREEN and NORMAL, due to insufficient coverage by ground-based monitoring data.
• An AVO Information Statement from May 8, 2026, gives further details about this activity and interpretations: https://avo.alaska.edu/news/hans/DOI-USGS-AVO-2026-05-08T19:12:14+00:00 
• Learn more about Mount Kupreanof and its current monitoring data on the AVO website: https://avo.alaska.edu/volcano/kupreanof 

The number of earthquakes, intensity of steam emissions, and measured sulfur dioxide emissions beneath Mount Kupreanof have declined. Due to these changes, the Alaska Volcano Observatory is lowering the Aviation Color Code and the Volcano Alert Level to UNASSIGNED. 

Summary of activity and hazards 

• Seismicity was first detected in February 2026 and increased over the following months, with earthquakes as large as magnitude 3.1 recorded. However, seismicity has declined over the past month.
• Sulfur dioxide (SO₂) emissions were detected beginning on April 4 with emission rates of ~100 to 1,000 tons per day, which are well above the background rate of <100 tons per day. These have dropped to background levels since late August.
• Collectively, these data likely indicate the magmatic intrusion beneath Mount Kupreanof has stalled.

Additional information: 

• The Aviation Color Code and the Volcano Alert Level are being changed to UNASSIGNED, rather than GREEN and NORMAL, due to insufficient coverage by ground-based monitoring data.
• An AVO Information Statement from May 8, 2026, gives further details about this activity and interpretations: https://avo.alaska.edu/news/hans/DOI-USGS-AVO-2026-05-08T19:12:14+00:00 
• Learn more about Mount Kupreanof and its current monitoring data on the AVO website: https://avo.alaska.edu/volcano/kupreanof 

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu has restarted. Episode 55 precursory overflows started from the north vent at 12:45 p.m. HST on September 7, which prompted the alert level to be raised to ORANGE and WATCH. A total of 29 overflows have occurred since then, with the most recent starting at 7:27 a.m. HST this morning. Overnight, moderate glow was often visible from the vents between overflows.  Summit reinflation has been very irregular since lava fountaining episode 54 on August 25 and over the past 24 hours has shown little change. Currently, summit tilt is about 0.5 microradians below the episode 54 starting level. A forecast window of September 9-10 is likely for the onset of episode 55 fountaining.

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

PRECURSORY ALERT LEVEL NOTICE: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-09-07T20:09:10+00:00

Summit Observations:

Webcam views over the past several days have been mostly obscured by heavy rain, clouds, and steam from Hurricane Lowell passing west of the Hawaiian Islands but the summit is clearing this morning. Weak spattering from the north vent was first reported at 6:54 p.m. HST on September 6, with the first sluggish precursory overflow from the north vent starting at around 12:45 p.m. HST on September 7. Overflows from the north vent have continued intermittently since then, with a total of 29 so far, lasting from 15 minutes to about 2 hours long and separated by interludes of about 15 minutes to 8 hours. The most recent north vent overflow started at 7:27 a.m. HST this morning. Overflows have become progressively more vigorous and been fed by a dome fountain that reached 15-30 ft (5-10 m) tall. Two main lava flows have 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. Between overflows, glow was observed from the north vent in webcam imagery when it was not obscured by rain and steam. No overflows occurred from the south or west vents, but occasional glow and flames were noted from these vents overnight in webcam imagery

Tremor continues across the summit with regular intervals (about 5 minutes) of gas piston activity. In the absence of views from webcams into the vents during overflow activity, changes in tremor signal were used to time the duration of many of the overflows from the north vent. Two 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 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 activity. Since then, there has been little change with slow inflation totaling 0.5 microradians. As of this morning, UWD remains at a similar amount of ground tilt it showed yesterday: approximately 12.3 out of 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. Trade winds have returned but continue to be weak this morning. The degassing plume is being pushed to the southwest of Kīlauea's summit caldera. Continued trade winds today could blow volcanic gases as well as fine ash and Peleʻs hair to the southwest of Kaluapele if episode 55 begins.

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, 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. The start of fountaining episode 55 could be preceded by a return to inflation or intermittent precursory north vent overflows could transition to a lava fountain later today or tomorrow. If tilt stalls for a longer period or if a prolonged deflation occurs, then the start of episode 55 could be delayed for several days.

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.