USGS Volcanoes: Notices released in the last day.

Slow eruption of lava within the summit crater continues with associated low level seismicity. Overnight satellite views showed elevated surface temperatures at the summit, consistent with the slowly growing lava dome. Web camera images were cloudy over the past day.  

The current eruption began in July 2021 and, 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. Web camera and satellite views were blocked by clouds. Sulfur dioxide emissions were detected in satellite data yesterday.

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 and infrasound detected during the past day. Sulfur dioxide emissions continue to be observed in satellite data. Web camera and satellite views were blocked by clouds.    

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 remains paused. Overnight, continuous weak glow was only observed from the north vent, the south vent and crack remained dark. Approximately 2.2 microradians of deflationary tilt has been recorded since early Friday morning. Current inflation models indicate that the forecast window for episode 53 has shifted to Tuesday-Thursday, August 11–14.

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

A summary of episode 52 is posted below.

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

Summit Observations:

Overnight, continuous weak glow was observed from the north vent, while no glow was observed from the south vent. A few small spots of incandescence were observed from the northern end of the new crack, where they have been a persistent feature. No flames or spatter were observed overnight, although glow from the north vent and incandescence from the fissure occasionally intensified coincident with gas piston spikes.

Irregular periods of gas pistoning continued overnight into this morning but occurred less frequently. Larger tremor spikes were spaced approximately 30 minutes to 2 hours apart. Three small, (<M1.0), earthquakes were detected across the broader Kīlauea summit region over the past 24 hours, one of which occurred within the northern wall of Halema'uma'u crater at approximately 5:45 a.m. HST.

Since the end of episode 52, the Uēkahuna (UWD) tiltmeter has recorded a net 10.1 microradians of inflationary tilt, after reaching a maximum of 12.3 microradians early Friday. Since 6:00 a.m. HST Friday, UWD has recorded approximately 2.2 microradians of deflation. Deflation slowed and leveled out from about 1 p.m. HST yesterday to 4 a.m. HST this morning, with no net gain or loss in tilt. A slow deflationary trend resumed on the UWD tiltmeter around 4:00 a.m. HST and continues this morning. Similar periods of deflationary tilt occurred just prior to episodes 51 and 52. Episode 52 produced 14.4 microradians of deflationary tilt at UWD. Summit tiltmeter SDH was offset a little over 1 microradian by a deep Pahala earthquake just after 4:30 a.m. HST.

Summit sulfur dioxide (SO₂) emission rates are likely varying within the typical range of 1,000–5,000 tonnes per day. Winds are currently light from the east-northeast at 6–10 mph, with gusts potentially reaching 18 mph. Degassing plumes from the north vent and new crack are being carried west-southwest, while degassing from the south vent remains minimal.

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 52 along with glow from the vents indicates that episode 53 fountaining is likely. Inflationary tilt since the end of episode 52 was interrupted by deflation from August 2 to 3. A second deflationary step began at 6:00 a.m. HST Friday morning and is continuing at this time. Deflations preceding the start of episodes 51 and 52 lasted for roughly 2-3 days. If the current trend follows a similar pattern, deflation may continue through today or tomorrow, (Sunday or Monday), before inflation resumes for another 1-2 days ahead of episode 53. This is consistent with current tilt-based models, which forecast the onset of episode 53 fountaining between August 11 and 14. The forecast window may be adjusted if summit tilt patterns change significantly.

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 that can be longer than three 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 52:

A detailed account of episode 52 is given in the HVO Status Report issued on July 29: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-29T13:10:51+00:00

• Episode 52 of the ongoing Halemaʻumaʻu eruption began around 7:10 p.m. HST on July 28 and ended abruptly at 2:36 a.m. HST on July 29, 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 emit flames at the end of the eruption. 
• The maximum plume height was approximately 19,000 (5,800 meters) above mean sea level. 

• Tephra fall was restricted mostly to the closed area of Hawaiʻi Volcanoes National Park to the 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, including the SDH tiltmeter, will remain offline until we are able to re-establish access across the deep tephra field southwest of the caldera.

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.