USGS Volcano Notice - DOI-USGS-HVO-2025-12-06T17:48:37+00:00

Activity Summary:

Precursory eruptions began yesterday and episode 38 is about to begin. The rate of summit inflation increased significantly in the past day and overflows began from the north vent just after noon. Continuous overflows began at 3:37 a.m. HST with fountains 20-30 feet (5-10 meters) high. The south vent had strong glow with intermittent spattering overnight.  Data indicate episode 38 is about to begin.

Summit Observations:

Precursory eruptions of degassed lava began from the north vent yesterday at 12:50 p.m. HST.  The first lasted for less than 2 minutes, but was followed by 3 longer overflows of 10-20 minutes between 5 and 8 p.m. HST last night.  The next overflow was another very short one at 2:35 a.m. HST followed by the onset of continuous overflows at 3:37 a.m. HST.  There have been two vents clearly separated by a septum of rock since the end of episode 37.  The right vent (looking from the V1 camera) is the original vent and the left vent is what remains of the backwall vent prior to episode 37.  Initially most of the continuous overflows were originating from the left vent and with a small amount draining back into the right vent and fountaining vigorously.  At about 7 a.m. HST the right vent began adding to the overflow and the effusion rate and fountain heights have increased steadily since then.  Fountains are currently 20-30 feet (5-10 meters) high and sustained.  The north vent is feeding a narrow ribbon-like flow into the center of Halema'uma'u crater.  The south vent has continued to glow and spatter intermittently but produced no overflows.  

Tremor has been increasing steadily all morning.

As of this morning, about 16.6 microradians of inflationary tilt have been recorded by UWD equaling the deflation during episode 37.  The summit is currently deflating.

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:

Tilt has equaled deflation during episode 37 and currently rapidly rising tremor and deflationary tilt indicate episode 38 is about to begin. 

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.