Newest Volcano Notice Including Kilauea

Activity Summary:

The ongoing Halemaʻumaʻu eruption is paused. Eruptive episode 31 ended abruptly at 2:52 a.m. HST on August 23 after over 12 hours of continuous lava fountaining. Last night, glow was consistently visible at the northern eruptive vent. Summit reinflation is underway at this time, and forecasting models suggest the likely window for episode 32 is later this week, between Wednesday, September 3 and Saturday, September 6. Episode 32 may occur even later if there are unexpected slowdowns in the summit inflation rate.

Summit Observations:

Glow was consistently visible in webcam views of the Halemaʻumaʻu north vent last night and somewhat brighter than previous nights. Brightening glow is an indication that active lava is slowly nearing the surface again.

The Uēkahuna tiltmeter (UWD) recorded about 22 microradians of deflationary tilt during episode 31, and the end of the episode on Saturday, August 23 coincided with a rapid change from deflation to inflation at the summit. Since then, UWD has recorded approximately 17.1 microradians of inflationary tilt in total. The end of the episode also saw a decrease in seismic tremor intensity; last night, the gas pistoning tremor cycles that has been ongoing for several days transitioned into persistent low-level tremor, which continues at this time.

Elevated degassing continues from the eruptive vents. Average sulfur dioxide (SO₂) emission rates during inter-episode pauses are typically 1,200 to 1,500 tonnes/day, though emission rates vary on short timescales in association with gas pistoning.  

Strands of volcanic glass known as Pele’s hair are present throughout the summit area of Hawaiʻi Volcanoes National Park and surrounding communities, and can be remobilized by wind even after lava fountaining has ceased.

• 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
• Three Kīlauea summit livestreams that show the eruptive vents are available here: https://www.youtube.com/@usgs/streams 
• Other summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams
• Volcano Watch article on gas pistoning: https://www.usgs.gov/observatories/hvo/news/volcano-watch-so-what-earth-or-least-kilauea-a-gas-piston

Rift Zone Observations:

Rates of earthquakes and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone, with no notable seismicity in the past 24 hours. Sulfur dioxide (SO₂) emissions from the East Rift Zone remain below the detection limits of nearby monitoring instruments.

Analysis: 

The return of summit inflation and gas pistoning after the end of episode 31 indicates that another eruptive episode in Halemaʻumaʻu is probable. Based on the present level of reinflation and the prevailing inflationary tilt rate, forecasting models suggest the likely window for episode 32 is later this week, between Wednesday, September 3 and Saturday, September 6. However, the inflationary tilt rate may unexpectedly slow for hours to days at a time; similar events have occurred during previous inter-episode pauses and they have delayed the onsets of the subsequent eruptive episodes.

The current eruption has been characterized by episodic lava fountaining not seen in any eruptions since the 1983–86 episodic fountains at the beginning of the Puʻuʻōʻō eruption. Lava fountains and flows have erupted from two vents within Halemaʻumaʻu crater that we refer to as the north vent and south vent. Each of the previous fountaining episodes lasted from a few hours to over a week and was accompanied by strong deflation of the summit region. Pauses between the fountaining episodes have been marked by an immediate switch from deflation to inflation as the magma chamber recharges and repressurizes. Fountaining episodes have occurred approximately once per week since the start of the current eruption on December 23, 2024.

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.

Hazards: 

This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—are one major hazard of concern, as this hazard can have far-reaching effects downwind. As SO₂ is continuously released from the summit during an eruption, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) downwind of Kīlauea. SO₂ and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/.

Another major hazard is fallout of Pele's hair and other volcanic fragments from lava fountains. Pele's hair is strands of volcanic glass often produced by lava fountaining activity that can be carried well over 10 miles (15 kilometers) from the vent. Other hot glassy volcanic fragments (tephra) including volcanic ash, pumice, scoria, and reticulite can fall on the ground within 1-3 miles (1-5 kilometers) of the eruptive vent(s), with the highest concentrations immediately downwind of the vent(s). Various volcanic fragments have fallen on Highway 11 west of Hawai'i Volcanoes National Park at times, depending on wind and eruption conditions. Strong winds may waft light particles, including Pele's hair, to greater distances downwind. Once on the ground, Pele's hair can sometimes cluster and tangle together, giving it the appearance of a tumbleweed. The extent of Pele's hair deposition is dependent on lava fountaining activity and wind conditions. Residents and visitors should minimize exposure to Pele's hair and other glassy volcanic fragments, which can cause skin and eye irritation and can also contaminate catchment water supplies. More information about how Pele's hair, its hazards, and what to do is available here: https://www.usgs.gov/observatories/hvo/news/volcano-watch-recent-lava-fountains-highlight-peles-hair-hazards. A recently updated Frequently Asked Questions document that includes information about potential health effects of Pele's hair is available here: https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.pdf.

Hawaiian lava flows generally advance slowly downslope, and during this eruption flows have been confined to Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera.

Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. 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.