USGS Volcanoes: Notices released in the last day.

No additional signs of unrest have been detected following the short‑duration explosion on October 1. 

Gareloi volcano persistently emits magmatic gases from a fumarole field on the south crater and commonly exhibits low-level seismic activity. These observations suggest the presence of shallow magma and potential interaction with a hydrothermal system. This October 1 explosion likely reflects a change to the magmatic-hydrothermal system, but it is not clear that the likelihood of a volcanic eruption has increased. AVO will continue to monitor activity to determine if the recent changes are related to influx of new magma or other changes to the magma system.

Mount Gareloi is monitored by a local seismic and infrasound network, satellite data, and regional infrasound and lightning-detection networks.

Lava continues to erupt slowly within the summit crater of Great Sitkin Volcano. Minor earthquakes were detected in the past day. No activity was observed in cloudy 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.

Unrest continues with elevated seismic and infrasound activity. No activity was observed in cloudy satellite and webcam images over the past day.

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. 

Monitored CALIFORNIA VOLCANOES
Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN

Activity Update: All volcanoes monitored by CalVO show normal background earthquake activity and deformation. Monitored volcanoes include Mount Shasta, Medicine Lake Volcano, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.

Past Week Observations for September 28 (0000h PDT) to October 04 (2359h PDT):

One earthquake greater than M1 was recorded within the Clear Lake Volcanic Field, with a magnitude of M1.8.

Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 92 earthquakes greater than M1 were recorded, with the largest having a magnitude of M2.6.

Six earthquakes greater than M1 were recorded in the Sierra Nevada Block, south of Mammoth Mountain and Long Valley, with the largest having a magnitude of M1.9.

Two earthquakes greater than M1 were recorded in the Coso Volcanic Field, with the largest having a magnitude of M1.6.

One earthquake greater than M1 were recorded near the Salton Buttes, with the largest having a magnitude of M1.6.

Overview:

There was strong glow and flames from north and south vents overnight, and south vent spattered at 1:19 a.m. H.S.T. this morning. The summit intrusion that happened the night of September 30 to October 1 has not reactivated. Summit tiltmeters recorded minor inflation.

Episode 55 fountaining remains a possibility during the ongoing Kīlauea summit eruption. It is also possible that intrusive activity below Kīlauea summit caldera could resume and potentially lead to the eruption of lava in a new location within the caldera.

No anomalous seismic activity or deformation has occurred outside of the summit region, and no significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.

STATUS REPORT published during intrusive activity: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-10-01T08:14:21+00:00

VOLCANO WATCH summarizing recent intrusive activity: https://www.usgs.gov/observatories/hvo/news/volcano-watch-intrusion-during-eruption-summit-kilauea 

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

Summit Observations:

There was strong glow and flames from north and south vents overnight, and south vent spattered at 1:19 a.m. H.S.T. this morning. It is possible that there were other instances of spattering. An intrusion underneath Kaluapele, the Kīlauea summit caldera, started the afternoon of September 30 and ended on October 1 at around 4 a.m. H.S.T. South vent only had one overflow after the intrusion, ending just before 6 a.m. on October 1, and north vent's last overflow was also on October 1, just after 6 a.m. H.S.T. 

Earthquakes activity below Kaluapele has decreased following the intrusion. In the past 24 hours, there was 1 shallow earthquake located across the summit region. The Uēkahuna tiltmeter (UWD) recorded approximately 0.6 microradians of inflation.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 and 5,000 tonnes per day. Winds are currently forecast from the north northeast.

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:

Monitoring data indicate that a shallow intrusion occurred the afternoon of September 30 through to the morning of October 1 underneath Halemaʻumaʻu. The intrusion did not reactive in the past 24 hours, although conditions can change rapidly, including eruption from a new vent with little or no seismicity or deformation.

In the past 24 hours, there was no spattering or overflows at north or south vents. Forecast windows for a potential episode 55 can no longer be modeled due to the irregular changes in inflation and deflation. The north vent has produced the last 11 high fountain events (episodes 44–54). It is not possible to say with certainty that this activity will lead to the onset of another fountain event at this time, although conditions remain favorable.

Because the summit system remains active and highly pressurized, the two most likely possibilities are that activity continues at the north-south-west vent complex, or it activates another existing weak crack system in the summit region. Neither 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:

Eruptive activity since December 2024 has been occurring within a closed area of Hawai'i Volcanoes National Park. However, this week's intrusion highlights 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 Kilauea 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 crater remain confined to Halemaʻumaʻu and Kaluapele. Lava flows from the eruption that started in December 2024 have been confined to Halemaʻumaʻu, an area closed to the public. 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.