USGS Volcano Notice - DOI-USGS-HVO-2026-08-12T16:32:18+00:00

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu remains paused. Glow strengthened overnight at the north vent and new collapse. Strong gas pistoning began at 4 a.m. HST with large flames from the new collapse accompanying tremor peaks. Weak glow also returned to the south vent around 4:30 a.m. HST. Rapid inflation began yesterday morning, and 3.9 microradians of inflationary tilt were recorded by the Uēkahuna (UWD) tiltmeter in the past 20 hours. However, inflation rates have slowed this morning beginning around 6:00 a.m. HST. Inflation-based models forecast the start of episode 53 fountains sometime later today, August 12, through Friday, August 13, depending on inflation rates.

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

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:

In the early evening, continuous weak to moderate glow was observed from the north vent, while the south vent remained dark. Around 8:45 p.m. HST, weak glow began to be visible from the new collapse (formerly called the new crack or fissure until overflight photos yesterday showed it to be a collapse). Glow strengthened to moderate from both north vent and the new collapse just before 10 p.m. HST, but the south vent remained dark. In the early morning hours, glow gradually brightened, becoming brightest with the return of tremor bursts associated with gas pistoning at 4:00 a.m. HST. In addition to bright glow, large flames were observed every 5-10 minutes from the collapse, correlating with tremor bursts. Moderate glow also returned to the south vent during these events.  

Low-moderate tremor continued overnight with the addition of periodic tremor bursts beginning at 4:00 a.m. HST. The tremor bursts were associated with strong glow and flames from the new collapse and the return of glow to the south vent, all of which suggest a return to gas pistoning behavior. One very small (less than M1.0) earthquake was detected near the center of Halemaʻumaʻu crater over the past 24 hours. 

The Uēkahuna (UWD) tiltmeter recorded the onset of rapid inflation beginning at 10:30 a.m. HST yesterday, gaining 3.9 microradians of tilt overnight before slowing down around 6 a.m. HST this morning. The UWD tilt meter has regained 13.9 microradians of the 14.4 microradians of deflationary tilt lost during episode 52. An offset in tiltmeter data at 5:48 pm yesterday is due to a M5.2 earthquake occurred near Kamaʻehuakanaloa. 

During inter-episode pauses, sulfur dioxide (SO₂) emission rates typically vary between 1,000–5,000 tonnes per day. Winds are currently from the northeast and are expected to remain that way until sometime Friday when weather may be influenced by the approaching tropical disturbance. 

Rift Zone Observations:

Rates of seismicity and ground deformation remain low in the East Rift Zone. SO₂ emissions from the East Rift Zone remain below the detection limit.

Seismicity has returned to normal background in the Southwest Rift Zone after a swarm of 18 small earthquakes were recorded Monday morning between 4:00 - 6:20 a.m. HST.

Analysis:

The abrupt switch from summit deflation to inflation at the end of episode 52, along with continued 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 and continued through Tuesday at 10:30 a.m. HST when rapid inflation began. The rapid inflation gained nearly 4 microradians in the past 22 hours regaining most of what was lost during the episode 52 fountain event. However, inflation slowed at about 6 a.m. HST and is continuing at a very slow rate. Small steps of slow to no inflation preceded the onset of episodes 51 and 52 fountains. The combination of prior deflations and tilt-based models have been used to forecast the onset of episode 53 fountaining between later today, August 12 through Friday, August 14. The forecast window may be adjusted if summit tilt rates continue to change.

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.