USGS Volcanoes: Notices released in the last day.

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 or 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 activity detected during the past day. Sulfur dioxide emissions were observed in satellite data in 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. 

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused. Data from summit tiltmeters inflation continuing. Glow was observed on webcams from the north and west vents overnight.  Inflation data suggest that another episode is likely between Saturday August 22 and Wednesday August 26.

WARNING: NWS forecasts the possible arrival of another tropical storm system this weekend with potential torrential rains.  Overlap with an eruption may create extreme conditions not suitable for viewing.  Watch for closures.  All of Hawaiʻi Volcanoes National Park, including USGS HVO facilities, remain without power since Hurricane Lala.

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

USGS HVO continues to experience sporadic outages due to power and possible storm damage related to Hurricane Lala. 

A summary of episode 53 that ended August 13 is posted below.

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

Summit Observations:

Continuous moderate to strong glow from the north vent was present overnight. Weak glow, intermittent glow from the west vent strengthened overnight to nearly continuous moderate glow visible on the V1 and V3 cameras.  The south vent remained dark.

Continuous low-level seismic tremor with occasional ragged tremor spikes occurred over most of the last 24 hours.  There were three earthquakes recorded in the summit area in the past 24 hours. 

The Summer Camp (SMC) tiltmeter has recorded a total of 15.1 microradians of inflationary tilt since the end of episode 53 and increased by 1.8 microradians in the last 24 hours. Deflationary tilt measured at the summit tiltmeter at SMC totaled 19.1 microradians during episode 53. UWD continues to have intermittent data outages due to lingering effects of Hurricane Lala.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 to 5,000 tonnes per day. Winds are currently from the northeast blowing the gas plume to the southwest.

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. There has already been one deflationary step beginning early on Friday August 14, before the arrival of Hurricane Lala, suggesting the stepwise reinflation that preceded episodes 52 and 53 may continue as we approach episode 54. The deflationary steps are not possible to forecast and interfere with the normal episode forecasts. Inflation data suggest that another episode is likely between Saturday August 22 and Wednesday August 26.

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.