USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly within the summit crater. Satellite data show that the lava dome is gradually expanding toward the east and slightly elevated surface temperatures were observed when cloud cover did not obscure the volcano. Seismic activity remains low, with only occasional small volcanic earthquakes and seismic signals associated with minor rockfalls.

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.

Low-level unrest continues at Mount Kupreanof. Local earthquakes have been occurring at a low rate. Robust steam emissions from the fumarole field on the southwest flank of Kupreanof were observed in web camera images, and emissions of sulfur dioxide gas were observed in satellite data this past week. 

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. 

Volcanic activity remains elevated with numerous small earthquakes, persistent tremor, and frequent infrasound signals generated by small explosions within the volcanic conduit. During periods of clear weather, a robust a steam plume was observed in web camera and satellite images and by numerous passing aircraft. Sulfur dioxide gas emissions continue to be observed in satellite data.

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. 

A large rock and ice avalanche on the eastern flank of Iliamna Volcano was detected by seismic and infrasound sensors at 07:57 AKDT (15:57 UTC) on Saturday, August 8. The source area of the avalanche was also visible in web camera data. Large avalanches are common at this volcano, and the event does not indicate volcanic unrest. Avalanches of similar size have been previously observed in 2016, 2019 and 2023.

Slow eruption of lava within the summit crater continues. Minor earthquakes were detected over the past day, likely associated with rockfall on the growing dome. 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.

Low-level earthquake activity continued over the past day. No activity was observed in cloudy satellite and webcam images. 

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.

Unrest continues with minor seismic and infrasound activity detected during the past day. No activity was observed in cloudy satellite and webcam images. Sulfur dioxide emissions were observed 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. 

Activity Update: All volcanoes in the Cascade Range of Oregon and Washington 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.

Past Week Observations: During the past week, small earthquakes were detected at Mount Rainier, Mount St. Helens, Mount Hood, and Newberry. All monitoring data are consistent with background activity levels in the Cascade Range. Field crews conducted station maintenance at Mount Rainier, and geologists are performing a field survey at Glacier Peak.

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused following 9.6 hours of lava fountaining during episode 53 on August 12-13, 2026. Data from summit tiltmeters showed re-inflation began immediately following the end of episode 53, suggesting that another episode is likely; however, mild deflationary tilt has been recorded since just after midnight last night. More data are needed to determine the forecast. 

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

A summary of episode 53 is posted below.

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

Summit Observations:

Weak, intermittent glow was seen from the north vent in Halema’uma’u overnight. No glow was visible from the south and west vents. Slow movements from cooling lava flows and gravity induced slumps on the vents are expected to continue in the coming days and nights. Strong northeasterly winds are pushing the degassing plume to the southwest over the Kaʻū Desert this morning.

Low-level seismic tremor with periodic seismic pulsing continues this morning, which is typical during inter-episode pauses. There were no earthquakes recorded in the summit area in the past 24 hours. 

Deflationary tilt measured at a summit tiltmeter at Uēkahuna (UWD) totaled 14.0 microradians during episode 53. Inflation resumed immediately upon cessation of fountains. Summit tiltmeters began recording mild deflation starting around midnight last night that continues into this morning. The UWD tiltmeter has recovered at total of 4.7 microradians of inflationary tilt since the end of episode 53.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 to 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.

Analysis:

The abrupt switch from summit deflation to inflation at the end of episode 53 along with glow from the vents indicates that episode 54 fountaining is likely. More inflationary tilt data are needed to determine the forecast window.

Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. A collapse pit in the slope behind the south vent formed a new west vent during episode 53. 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 53:

A detailed account of episode 53 is given in the HVO Status Report issued on August 13: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-08-13T11:52:10+00:00

• Episode 53 of the ongoing Halemaʻumaʻu eruption began around 3:45 p.m. HST on August 12 and ended abruptly at 1:23 a.m. HST on August 13, 2026.
• The maximum lava fountain height was approximately 500 feet (150 meters) above ground level from the north vent. The south vent never fountained during this episode but did produce overflows prior to the fountaining episode. A new west vent produced precursory overflows and emitted intermittent flames through most of the eruption. 
• The maximum plume height was approximately 18,000 (5,500 meters) above mean sea level. 

• Tephra fall was restricted mostly to the closed area of Hawaiʻi Volcanoes National Park, southwest of the active Halemaʻumaʻu vents.  

   

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 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.

NORTHERN MARIANAS VOLCANOES
No signs of significant unrest were detected at any Northern Mariana Island volcanoes 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.