USGS Volcano Notice - DOI-USGS-HVO-2025-12-07T17:59:55+00:00

Activity Summary:

Episode 38 ended yesterday, December 6, at 8:52 p.m. HST after 12.1 hours of sustained fountains and eruptive activity. Moderate glow from both vents overnight, rapid rebound of summit inflation, and continued tremor indicate that another fountain episode is likely.  The onset of another episode is at least 2 to 3 weeks away. 

Summit Observations:

Both vents showed moderate glow overnight after the end of fountaining last night.  Incandescent lava on the floor of Halemaʻumaʻu crater gradually cooled and went dark overnight.  However, spatter-fed flows on the slopes south of both vents remain partially incandescent and continue to creep downslope this morning. Moderate tremor with regular spikes suggests gas pistoning is occurring deep within the vents.

Inflation is showing the typical rapid rebound with over 3 microradians since the end of episode 38 last night after losing over 33 microradians during the eruption.  

Volcanic gas emissions have greatly decreased with the end of the eruption and are back in the normal range of 1200 to 1500 tonnes per day of SO₂.

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:

The rapid rebound of inflationary tilt, continued tremor, and moderate glow from both vents overnight all indicate another fountaining episode is likely. It is currently too early to make an accurate forecast. Based on current conditions and past events, the onset of another fountain episode is at least 2-3 weeks away at this time.

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 38 fountaining from the south vent stopped at approximately 8:52 p.m. HST on December 6 after 12.1 hours of sustained fountaining. The two vents within the north vent both stopped much earlier at 11:50 a.m. HST.  Sustained fountaining began at 8:45 a.m. HST from the two vents in the north cone after about 5 hours of precursory overflows.  The south vent fountain began at 8:49 a.m. HST and within 10-20 minutes all three fountains were about 500 (150 m) high creating a rare triple fountain.  By 9:40 a.m. the south vent fountain grew to about twice as high as the north vent fountains. The highest peak or instantaneous effusion rate of 1,300 cubic yards per second (1,000 cubic meters per second) occurred just before 10 a.m. when the south vent exploded. The enlarged south vent produced an inclined fountain over 1,000 feet (300 meters) tall that sprayed the south wall of Halemaʻumaʻu crater. Hot pumice and molten spatter from this fountain destroyed the HVO "V3" streaming camera site. The south fountain gradually dropped in height throughout the afternoon to about 500 feet (150 meters) high along with declining effusion rates. Episode 38 ended with an average effusion rate of 250 cubic yards per second (190 cubic meters per second). An estimated 16.5 million cubic yards (12.6 million cubic meters) of lava erupted and covered about 50-60% of the floor of Halemaʻumaʻu crater. The Uēkahuna tiltmeter (UWD) recorded about 33.1 microradians of deflationary tilt during episode 38.

The following notices from December 6 provide more information about episode 38:

• Volcano Activity Notice for End of Eruption (9:08 PM HST)
• Status Report on Fountain Height and Loss of V3 camera (10:41 AM HST)
• Volcano Activity Notice for Start of Eruption (8:48 AM HST)
• Kīlauea Update for December 6 (8:25 AM HST)

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
• Two 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.