USGS Volcano Notice - DOI-USGS-HVO-2025-12-05T22:02:06+00:00

Note: The Friday morning update for Kīlauea is being reissued to correct an editing problem in the Activity Summary section.

Activity Summary:

The rate of summit inflation increased yesterday and both vents had moderate-strong glow overnight with intermittent spattering from the north vent.  Models indicate he onset of episode 38 fountains will occur between December 6 and 8, with Saturday and Sunday, December 6-7, most likely.

Summit Observations:

The south vent had moderate glow overnight while the north vent became increasingly active with stronger glow from the vent beginning about 11:40 HST followed by increasing spattering events after about 3:30 HST.  Spattering indicates that magma is standing high in the column. Large flames continued to within the south vent and from the crack adjacent to the north vent, presumably due to burning of hydrogen gas.  Persistent low to moderate tremor was punctuated by multiple periods of tremor bursts suggestive of gas pistoning. These periods increased in frequency overnight. 

As of this morning, about 14.8 microradians of inflationary tilt have been recorded by UWD since the end of episode 37, with increased inflation recorded in the past day. 

Rift Zone Observations:

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

Analysis:

Increased inflationary tilt overnight along with stronger glow, intermittent spatter, and strong gas pistoning indicates that episode 38 fountaining is likely to start soon.  Small, precursory eruptions of degassed lava may begin erupting from the vents at anytime.  Models indicate that episode 38 fountains are likely to begin between December 6 and 8, with December 6 and 7 most likely.  The forecast may continue to change if there are more changes in the rate of summit inflation. 

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

Recap of previous episode:

Episode 37 fountaining from the north vent stopped at approximately 11:39 p.m. HST on November 25. The south vent was not active during episode 37. Fountains from the north vent reached maximum heights of 500-600 ft (150-180 m). Fountaining lasted for 9.2 hours at an average rate of rate of about 250 cubic yards per second (190 cubic meters per second). Episode 37 produced an estimated 8.2 million cubic yards (6.3 million cubic meters) of lava and covered about 75% of the floor of Halemaʻumaʻu crater. The Uēkahuna tiltmeter (UWD) recorded about 16.5 microradians of deflationary tilt during episode 37.

The following notices provide more information about episode 37::

• VAN VONA End of Episode 37
• VAN VONA Start of Episode 37

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
• Three Kīlauea summit livestream videos 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. 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.