USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly within the summit crater. Minor earthquakes were detected in the past day. Due to cloud cover, no activity was observed in satellite or web cam images.

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 minor seismic activity detected in the past day. Clouds obscured both satellite and webcam views.

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. 

Earthquake activity over the past activity was mostly quiet. Cloudy weather obscured satellite and webcam views.

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.

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused. Weak glow was periodically visible overnight from the north vent. Summit reinflation has been very irregular since lava fountaining episode 54 on August 25, and this reinflation has continued over the past day. The current reinflation pattern is similar to what followed the last few episodes. A forecast window of September 7-12 is likely for the next episode if inflation follows the prior patterns.

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

Summit Observations:

Overnight webcam views showed weak glow periodically from the Halemaʻumaʻu north vent, at times possibly coinciding with tremor patterns indicative of gas pistoning. Release and combustion of volcanic gas (likely hydrogen) appears to be occurring deep within the vent, in association with larger tremor bursts observed in seismic data streams. The lack of consistent glow suggests that incandescent magma remains relatively deep in the vent and possibly crusted over between gas release bursts.

Low level tremor continues to be recorded on summit seismometers, tremor bursts have been sporadic over the past 24 hours. A single shallow earthquake was recorded beneath the summit region over the past 24 hours.

Summit reinflation has been very unsteady since lava fountaining episode 54 on August 25, and it began increasing again around 3:00 p.m. HST on September 1. As of this update, the Uēkahuna (UWD) tiltmeter has measured a peak of 7.8 microradians of inflation relative to the end of lava fountaining episode 54, with about 2.5 over the past 24 hours. Since approximately 6:00 a.m. HST this morning, tilt at UWD has been flat to very slightly deflationary. Deflationary tilt on UWD totaled 12.7 microradians 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. Strong trade winds are pushing the degassing plume to the southwest over the Kaʻū Desert this morning.

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 and continued seismic tremor bursts from the Halemaʻumaʻu eruptive vents indicate that another lava fountaining episode may occur in the coming weeks. Reinflation has been slow and irregular, having been interrupted by multiple deflations of varying magnitude and duration. After inflating over 4 microradians from September 1-3, weak deflation began this morning, continuing the stepwise trend. Coupled with minimal vent glow, these observations suggest that magma is relatively deep in the vent conduits at this time. The recent summit inflation appears to be following a pattern similar to the last 4 pauses allowing modeling of a broad forecast window of Monday, September 7, to Saturday, September 12, for the potential onset of episode 55 fountains.

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.

No significant activity was detected at Ofu-Olosega volcano during the past month. The USGS National Earthquake Information Center reported no earthquakes of magnitude 2.5 or greater in the vicinity of the volcano. 

No significant activity was detected at Taʻū volcano during the past month. The USGS National Earthquake Information Center reported no earthquakes of magnitude 2.5 or greater in the vicinity of the volcano. A Global Positioning System (GPS) instrument on Taʻū Island recorded no significant deformation.

The FAGA broadband seismometer located on eastern Taʻū Island is currently out of service. The TAU broadband seismometer on western Taʻū Island remains operational.

The TAU1 GPS station has experienced intermittent data outages and HVO is evaluating the quality of transmitted data.

No significant activity was detected at Tutuila volcano during the past month. The USGS National Earthquake Information Center reported no earthquakes of magnitude 2.5 or greater in the vicinity of the volcano.

Mauna Loa had an increase in seismic activity compared to the previous month; a total of 87 earthquakes were detected in Mauna Loa's summit region during the August reporting period, after 57 in July. Most earthquakes occurred deep beneath the upper Southwest Rift Zone or broadly scattered around the upper flanks. Very few earthquakes occurred directly beneath Mokuʻāweoweo.

Data from Global Positioning System (GPS) instruments on Mauna Loa showed slight inflation across the summit region in the past month. Most GPS stations at the summit recorded small upward vertical motions while shifting radially away from the caldera in the horizontal direction. Oscillations between contraction and inflation patterns during non-eruptive periods are normal, but inflation has been the dominant trend since the 2022 eruption, with magma refilling the summit reservoir system.

Gas and temperature data from a station on Mauna Loa's Southwest Rift Zone indicate these values are at background levels, with little change relative to previous months.

HVO continues to closely monitor Mauna Loa and will issue another update in one month, or earlier, should conditions change significantly.

No significant activity was detected at Hualālai volcano during the past month. Seismic activity remained low and was representative of background activity levels at the volcano. The continuously recording Global Positioning System (GPS) instrument on Hualālai has been offline since March 15, 2026; HVO field engineers will service the station within the next few months to bring it back online.

No significant activity was detected at Haleakalā volcano during the past month. The continuously recording Global Positioning System (GPS) instrument on Haleakalā lost connection on July 13th. No significant deformation was recorded leading up to the outage. The station is owned and operated by researchers at the Pacific GPS Facility (PGF), as part of the Hawaii Institute of Geophysics and Planetology (HIGP), who will service the station within the next few months to bring it back online.

No significant activity was detected at Mauna Kea volcano during the past month. Seismic activity remained low and was representative of background activity levels at the volcano. The continuously recording Global Positioning System (GPS) instrument on Mauna Kea, operated by NASA's Jet Propulsion Laboratory, recorded no significant deformation in the past month.
 

No significant activity was detected at Kamaʻehuakanaloa volcano (formerly Lōʻihi Seamount) during the past month. Seismic activity remained low and was representative of background activity levels at the volcano.

No activity was observed in occasional clear satellite images or 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.