USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly within the summit crater of Great Sitkin Volcano. Earthquake and rockfalls signals consistent with the growth of the lava dome were observed in seismic data. Clouds obscured satellite and webcam images over the past day.

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.

Slightly elevated seismic and infrasound activity continues. Minor degassing was visible in clear webcam images, and sulfur dioxide 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. 

Lava continues to erupt slowly within the summit crater of Great Sitkin Volcano. Earthquake activity consistent with the growth of the lava dome was observed. Clouds obscured satellite and webcam images over the past day.

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.

Slightly elevated seismic and infrasound activity continues. Minor degassing was visible in a few clear webcam images. Nothing of note was seen in partly clear satellite images. 

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:

Precursory overflows from the north vent resumed overnight. Glow and flames continued from the north-south-west vent complex throughout the night, with intermittent spatter bursts from the north and south vents. There are currently no signs of activity at the recent vents 1-6. Summit tilt has been relatively flat over the past 24 hours, with slight deflation starting early this morning. Over the past 24 hours continuous tremor remains the dominant seismic signal across the summit. No anomalous seismic activity or deformation has occurred outside of the summit region. 

HVO is maintaining the Alert Level for Kīlauea at WATCH and the Aviation Color Code at ORANGE, and posted a Volcanic Activity Notice last night to highlight the resumption in precursory activity: USGS Volcano Notice - DOI-USGS-HVO-2026-09-23T08:36:47+00:00

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

STATUS REPORT on changes in activity and implications for this eruption: USGS Volcano Notice - DOI-USGS-HVO-2026-09-15T03:18:09+00:00

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

Summit Observations:

Precursory overflows from the north vent resumed last night, September 22, beginning at 10:10 p.m. HST. Additional overflows began at 11:44 p.m. HST on September 22, and 2:46 a.m., 6:10 a.m., and 7:04 a.m. HST on September 23. Each overflow lasted about 30 minutes and produced lava flows that traveled a few hundred meters (yards) from the vent. The were all fed by vigorous fountains from the small 30-50 foot (10-15 meter)The north, south, and west vents continued to glow and emit flames. Intermittent spatter bursts were also observed from the north and south vents last night. No other areas of incandescence were observed across the summit region last night.

Strong continuous tremor is the dominant seismic signal across the summit. There were nine small earthquakes located across the summit region in the past day, but they did not form clusters in time or location. 

Summit tilt has been relatively flat over the past day, with about 0.3 microradians of deflation recorded since about 3:00 a.m. HST this morning. The current total inflation since the end of episode 54 is about 15.7 microradians, slightly less than the maximum of 16 microradians reached on September 16 and more than two microradians greater than was lost during episode 54 fountaining.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 and 5,000 tonnes 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. No significant ground deformation was recorded in either rift zone.

Analysis:

The north vent resumed precursory overflow activity last night. In addition, the north, south, and west vents continued to glow and emit flames, with intermittent spatter from the north and south vents last night. Strong continuous tremor dominates the seismic signal within the summit. Forecast windows for this episode can no longer be modeled due to the irregular changes in inflation and deflation. Since reaching a peak inflation of 16 microradians (UWD tilt post episode 54) on Wednesday September 16, the summit deflated about 2.3 microradians as the new lava flows from vents 1-6 ceased. Slow inflation (recorded on the UWD tiltmeter) started Thursday September 17 and had since recovered about 2.1 of the 2.3 microradians lost to the deflation event. Deflation resumed early this morning, recording a loss of 0.3 microradians after the onset of overflows. Current eruptive activity is focused on the north vent, which has produced the last 11 high fountain events (episodes 44-54). However, it is not possible to say with certainty that this activity will lead to the onset of another fountain event at this time.

Because the summit system remains active, the three most likely possibilities are that activity continues at the north-south-west vent complex, or reactivates the vent 1-6 system, or intrudes another existing weak crack system in the summit region. None of these events are likely to produce a strong seismic precursor, so the alert levels have been left at ORANGE/WATCH as the volcano continues to "exhibit heightened unrest with an increased potential for eruption". For further details about potential scenarios see the September 15 Status Report.

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.

Precursory low-level activity for episode 55 of the ongoing Halemaʻumaʻu eruption at the summit of Kīlauea restarted around 10:10 p.m. HST on September 22 with a vigorous lava flow from the north vent that lasted for 24 minutes. The initial overflow was followed by a second that started at 23:44 p.m. HST. The previous overflows from the north-south-west vent complex ended just before noon on September 12 after 5 days of eruptions. These were followed by the opening of vents 1 though 6 on September 14 along the northwest wall of Halemaʻumaʻu crater that last for two days.d It is presently unclear if this activity will lead to the onset of a lava fountaining episode at this time.  

Accordingly, HVO is maintaining the Alert Level for Kīlauea at WATCH and the Aviation Color Code at ORANGE. Alert level and aviation color code definitions: https://www.usgs.gov/programs/VHP/alert-level-system. This low-level precursory activity can continue for hours to days before the lava fountaining episode beings. Another VAN will be published when lava fountaining episode 55 begins.

• All eruptive vents and lava flows are confined to Halemaʻumaʻu crater within Hawaiʻi Volcanoes National Park. Tephra fall from volcanic ash clouds is greatest within 3 miles (5 km) of the vents, lighter ash and Pele's Hair may stay suspended for large distances from the vents.
• Support science and community awareness by reporting tephra fall: https://hawaiiash.science/report_form 
• Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://youtube.com/@usgs/streams 
• KPcam and MKcam provide views of the plume height for aviation purposes
• Additional short updates as the episode progresses will be posted here: https://www.usgs.gov/observatories/hvo/observatory-messages 
• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information 

Most lava fountaining episodes since December 23, 2024, have continued for a day or less.

Overview:

Glow and flames continued from the north-south-west vent complex throughout the night, with minor intermittent spatter from the north and south vents. Slow inflation continues at the summit, gaining approximately 0.2 microradians over the past day. Over the past 24 hours strong, continuous tremor remains the dominant seismic signal across the summit. No anomalous seismic activity or deformation has occurred outside of the summit region.

The system is within about a day, at the current slow rate of inflation, of reaching the maximum inflation of 16 microradians of tilt recovered since episode 54 fountaining ended. When this peak pressurization is reached, it is possible that activity will resume at the north-south-west vent complex, or reactivate the vent 1-6 system, or intrude another weak area in the summit region. None of these events are likely to produce a strong seismic precursor, so the alert levels remain at ORANGE/WATCH as the volcano continues to "exhibit heightened unrest with an increased potential for eruption".

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

STATUS REPORT on changes in activity and implications for this eruption: USGS Volcano Notice - DOI-USGS-HVO-2026-09-15T03:18:09+00:00

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

Summit Observations:

The north, south, and west vents continued to glow and emit flames. Intermittent spatter was also observed from the north and south vents last night. Flames from the north vent could be seen burning almost continuously in the early morning darkness. A very small, spatter-fed flow traveled about 15-35 feet (5-10 meters) from the north vent cone between 7:23-7:24 p.m. HST last night. No other significant spatter was deposited outside of the vents. No other areas of incandescence were observed across the summit region last night.

Strong continuous tremor is the dominant seismic signal across the summit. There were six small earthquakes located across the summit region in the past day, but they did not form clusters in time or location. 

Summit inflation continues this morning, recording an increase of about 0.2 microradians over the past day. The current total inflation since the end of episode 54 is currently about 15.8 microradians, slightly less than the maximum of 16 microradians reached on September 16 and more than two microradians greater than was lost during episode 54 fountaining.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 and 5,000 tonnes 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. No significant ground deformation was recorded in either rift zone.

Analysis:

The north, south, and west vents continued to glow and emit flames, with minor intermittent spatter from the north and south vents last night. Strong continuous tremor dominates the seismic signal within the summit. Forecast windows for this episode can no longer be modeled due to the irregular changes in inflation and deflation. Since reaching a peak inflation of 16 microradians (UWD tilt post episode 54) on Wednesday September 16, the summit deflated about 2.3 microradians as the new lava flows from vents 1-6 ceased. Slow inflation (recorded on the UWD tiltmeter) started Thursday September 17 and has since recovered about 2.1 of the 2.3 microradians lost to the deflation event.

The system is within about a day, at current very slow inflation rates, of returning to the peak pressurization that resulted in the opening of vents 1-6 with no seismic precursors. If inflation rates change or deflation occurs, this could change. Because the summit system remains active, the three most likely possibilities are that activity resumes at the north-south-west vent complex, or reactivates the vent 1-6 system, or intrudes another existing weak crack system in the summit region. None of these events are likely to produce a strong seismic precursor, so the alert levels have been left at ORANGE/WATCH as the volcano continues to "exhibit heightened unrest with an increased potential for eruption". For further details about potential scenarios see the September 15 Status Report.

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.