USGS Volcanoes: Notices released in the last day.

Minor growth of the active lava dome within the summit crater was observed in satellite imagery over the past week. The southeast lava lobe is not advancing but lava continues to flow into it. The south flank of the dome is moving slowly southward and generating occasional small rockfalls. Steaming and elevated surface temperatures were observed in satellite and webcam views when weather was clear. Seismic activity remains low with occasional small volcanic earthquakes and signals from minor rockfalls caused by lava‑flow growth. 

The current lava eruption began in July 2021 and has filled most of the summit crater and advanced into the valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic, geodetic, and infrasound sensors, satellite data, and web cameras, and regional infrasound and lightning networks. 

Volcanic activity remains slightly elevated. Small earthquakes, ongoing tremor, and possible infrasound signals have continued over the past week. During periods of clear weather, webcam views showed steaming from the summit area, and satellite data indicated minor sulfur dioxide emissions through much of the week. Overall, the frequency and magnitude of earthquakes, infrasound signals, and gas emissions have declined over recent months, indicating a gradual decrease in activity. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, the Alaska Volcano Observatory uses nearby geophysical networks, regional infrasound and lightning data, and satellite data to monitor the volcano. 

Activity Update: All volcanoes in the Cascade Range of Washington and Oregon are at normal background activity levels. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State and Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake in Oregon.

During the past week, small earthquakes were detected at Mount Hood, Mount Rainier, and Mount St. Helens. All monitoring data remain consistent with background activity levels throughout the Cascade Range. This week, field crews performed maintenance on monitoring stations at Three Sisters and Mount Rainier.  

On Thursday 15 Oct 2026, strong southeasterly winds resuspended volcanic ash in the vicinity of Mount St. Helens. The National Weather Service estimated that that the resulting ash cloud reached a maximum altitude of 12,000 ft (3,658 m) above sea level. This phenomenon is not the result of recent volcanic activity and occurs during times of high winds and dry, snow-free conditions in the Mount St. Helens region. 

Summit Observations:

Multiple overflows from the south vent were observed through the night starting at 10:16 PM HST. There were 15 overflows that lasted less than 5 minutes and were small, advancing less than 100 feet (30 m) from the vent. Then at 5:10 a.m. HST, a high-volume overflow coated the entire area within 300 feet (100 m) of the vent with pahoehoe in 10 minutes. This was followed by the current south vent overflows which began and 5:56 a.m. HST and continue at this time. A small dome fountain within the vent has been feeding multiple channels of pahoehoe that cover the near vent area and extend near a half a mile (about a kilometer) from the vent. The volume of lava and the size of the dome fountain appear to wax and wane over time, but continues to feed vigorous overflow channels. Spatter from all three vents (north, south, and west) was also observed overnight, as well consistent glow and occasional flames. 

Irregular tremor bursts gave way to more continuous tremor around 6 a.m. HST, about the same time the south vent became continuously active and drainback events stopped. Twenty-one earthquakes were recorded over the past day, mostly in the southern and eastern regions of the summit region of Kīlauea.

Summit tiltmeters have shown minor changes in tilt, with an overall slight inflationary trend since Wednesday. GPS stations on opposite sides of Halemaʻumaʻu (CRIM and UWEV) show a small increase in length since the end of September suggesting longer-term inflation of the summit magma reservoir.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 and 5,000 tonnes per day. Plumes of volcanic gas are visible from the vents in day-time webcam views. Winds are currently forecast from the north-northeast through 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. No significant ground deformation was recorded in either rift zone.

Analysis:

Kīlauea had been erupting episodically between December 23, 2024, and August 25, 2026, from two vents (north and south) in Halema‘uma‘u at the summit. Lava fountaining episodes generally lasted for less than 12 hours and were separated by pauses of two or more weeks. Irregular patterns of ground deformation at Kīlauea summit since the most recent lava fountaining episode, number 54 on August 25, 2026, prevent forecast modeling for when the next fountaining episode can occur. Ground deformation patterns indicate the magma chamber beneath Halemaʻumaʻu is pressurized beyond the level typically seen before recent fountaining events. This pattern was disrupted by the dike intrusion on September 30-October 1 and since then summit tilt has increased slowly with interspersed periods of decreased or flat tilt. The vigorous overflows from the south vent this morning indicate that magma remains very near the surface in the established vent complex and continues to be able to generate smaller dome fountains. It is possible that another fountaining episode from the north-south vent complex could occur; however, intrusive activity underneath Kaluapele is also possible, or magma could exploit existing weak crack systems in the summit region to erupt passively (with little or no seismicity or deformation). 

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. Kīlauea volcano alert level and aviation color code remain at WATCH/ORANGE and conditions could change rapidly. For further details, see the recent official notices listed below. 

• October 7 Status Report summarizing recent intrusive activity and implications: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-10-08T01:00:28+00:00 
• October 7 Hawaiʻi Volcanoes National Park News Release announcing closures related to recent activity: https://www.nps.gov/havo/learn/news/20261007-nr-trail-closures.htm 
• October 1 Volcano Watch summarizing recent intrusive activity: https://www.usgs.gov/observatories/hvo/news/volcano-watch-intrusion-during-eruption-summit-kilauea 
• October 1 Status Report published during recent intrusive activity: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-10-01T08:14:21+00:00
• September 15 Status Report on changes in activity and implications for this eruption: https://volcanoes.usgs.gov/hans-public/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

Hazards:

Eruptive activity since December 2024 has been occurring within a closed area of Hawai'i Volcanoes National Park. However, recent intrusions highlight that the location of eruptive activity could change. Intrusions can also be hazardous with potential to cause earthquakes, ground cracks, and small landslides. The primary hazards at Kīlauea due to eruptive activity and/or intrusions are:

• 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/ and https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.pdf 
• Lava flows: Hawaiian lava flows generally advance slowly downslope but destroy everything in their paths. Lava flows that erupt within Halemaʻumaʻu remain confined to the crater, including those during the eruption that started in December 2024. However, intrusive activity could result in lava flows outside of Halemaʻumaʻu. Hazards associated with active or recent lava flows include hot and glassy (sharp) surfaces that can cause serious burns, abrasions, and lacerations upon contact with unprotected or exposed skin; uneven and rough terrain can lead to falls and other injuries; hot temperatures that can cause heat exhaustion or dehydration, or in heavy rain can produce steamy ground-fog that can be acidic, severely limiting visibility and sometimes causing difficulty breathing.
• Earthquakes and ground cracks: Shallow magma movement and eruptions can produce minor to severe ground fractures and subsidence features. These ground cracks can continue to widen and offset as magma migration continues, may have unstable overhanging edges, and should be avoided. Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes.

Additionally, 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.

Summit Observations:

Overflows from the north vent resumed yesterday at 11:08 AM HST and continued intermittently throughout the day with 12 recorded by sundown, as well as one overflow from the south vent. Numerous instances of spatter from all three vents (north, south, and west) were also observed. Conditions overnight led to difficult viewing, nonetheless spatter was visible from all vents, as well as an additional overflow accompanied by gas jetting from the north vent at 4:46 AM. Glow and flames from the vents also continued consistently through the night.

Summit tremor continued throughout the day, with a return to irregular tremor bursts around 12:15 PM. In the past 24 hours, there were 20 shallow earthquakes located across the summit region of Kīlauea, predominantly in the south caldera region. 

Summit tiltmeters have shown minor changes in tilt, with an overall slight inflationary trend over the past day. GPS stations on opposite sides of Halemaʻumaʻu (CRIM and UWEV) show a small increase in length since the end of September suggesting longer-term inflation of the summit magma reservoir.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 and 5,000 tonnes per day. Plumes of volcanic gas are visible from the vents in day-time webcam views. Winds are currently forecast from the north-northeast through 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. No significant ground deformation was recorded in either rift zone.

Analysis:

Kīlauea had been erupting episodically between December 23, 2024, and August 25, 2026, from two vents (north and south) in Halema‘uma‘u at the summit. Lava fountaining episodes generally lasted for less than 12 hours and were separated by pauses of two or more weeks. Irregular patterns of ground deformation at Kīlauea summit since the most recent lava fountaining episode, number 54 on August 25, 2026, prevent forecast modeling for when the next fountaining episode can occur. Ground deformation patterns indicate the magma chamber beneath Halemaʻumaʻu is pressurized beyond the level typically seen before recent fountaining events. This pattern was disrupted by the dike intrusion on September 30-October 1 and since then summit tilt has increased slowly with interspersed periods of decreased or flat tilt. The vigorous overflows yesterday indicate that magma remains very near the surface in the established vent complex and continues to be able to generate smaller fountains. It is possible that another fountaining episode from the north-south vent complex could occur; however, intrusive activity underneath Kaluapele is also possible, or magma could exploit existing weak crack systems in the summit region to erupt passively (with little or no seismicity or deformation). 

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. Kīlauea volcano alert level and aviation color code remain at WATCH/ORANGE and conditions could change rapidly. For further details, see the recent official notices listed below. 

• October 7 Status Report summarizing recent intrusive activity and implications: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-10-08T01:00:28+00:00 
• October 7 Hawaiʻi Volcanoes National Park News Release announcing closures related to recent activity: https://www.nps.gov/havo/learn/news/20261007-nr-trail-closures.htm 
• October 1 Volcano Watch summarizing recent intrusive activity: https://www.usgs.gov/observatories/hvo/news/volcano-watch-intrusion-during-eruption-summit-kilauea 
• October 1 Status Report published during recent intrusive activity: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-10-01T08:14:21+00:00
• September 15 Status Report on changes in activity and implications for this eruption: https://volcanoes.usgs.gov/hans-public/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

Hazards:

Eruptive activity since December 2024 has been occurring within a closed area of Hawai'i Volcanoes National Park. However, recent intrusions highlight that the location of eruptive activity could change. Intrusions can also be hazardous with potential to cause earthquakes, ground cracks, and small landslides. The primary hazards at Kīlauea due to eruptive activity and/or intrusions are:

• 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/ and https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.pdf 
• Lava flows: Hawaiian lava flows generally advance slowly downslope but destroy everything in their paths. Lava flows that erupt within Halemaʻumaʻu remain confined to the crater, including those during the eruption that started in December 2024. However, intrusive activity could result in lava flows outside of Halemaʻumaʻu. Hazards associated with active or recent lava flows include hot and glassy (sharp) surfaces that can cause serious burns, abrasions, and lacerations upon contact with unprotected or exposed skin; uneven and rough terrain can lead to falls and other injuries; hot temperatures that can cause heat exhaustion or dehydration, or in heavy rain can produce steamy ground-fog that can be acidic, severely limiting visibility and sometimes causing difficulty breathing.
• Earthquakes and ground cracks: Shallow magma movement and eruptions can produce minor to severe ground fractures and subsidence features. These ground cracks can continue to widen and offset as magma migration continues, may have unstable overhanging edges, and should be avoided. Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes.

Additionally, 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.

Plumes of discolored water were seen in the ocean above Ahyi on October 9 and 11 this past week. Discolored greenish water was visible drifting more than 7 km from the summit of Ahyi. These plumes are likely associated with degassing and hydrothermal activity at the summit of the underwater volcano. No notable activity was detected in distal geophysical monitoring data over the past week. 

Eruptive activity at Ahyi seamount may present a hazard to mariners in the water above and near the volcano. The summit has shallowed over the course of previous eruptions to 180 feet (55 m) below sea level, but the lack of local real-time data means we are unable to forecast or warn of impending eruptions. We will continue to monitor satellite and distal hydroacoustic data for additional evidence for, or escalation of, volcanic activity.

NORTHERN MARIANAS VOLCANOES
No signs of unrest were detected at any Northern Mariana Island volcanoes besides Ahyi Seamount during the past week. 

Monitoring of Northern Mariana Islands Volcanoes

Northern Mariana Island volcanoes are monitored using seismo-acoustic sensors on Saipan, and by examining satellite imagery. We also use distant seismic stations in Guam and Chichijima, Japan, and hydroacoustic data from Wake Island, when available.

This level of monitoring can detect significant volcanic activity in the CNMI but cannot provide advanced warning of eruptions.

Due to a lack of geophysical monitoring on any of the volcanic islands, the following volcanoes have alert levels of UNASSIGNED: Anatahan, Sarigan, Farallon de Pajaros, Supply Reef, Maug, Asuncion, Agrigan, Pagan, Almagan, and Guguan.