USGS Volcano Notice - DOI-USGS-HVO-2025-06-05T15:46:23+00:00

Activity Summary:

Episode 24 of the ongoing Halema'uma'u eruption ended this morning at 4:28 a.m. after about 7.5 hours of sustained fountaining. The end of the eruption was coincident with a rapid change from deflation to inflation at the summit and a decrease in seismic tremor intensity. Summit inflation has resumed, along with persistent, low level seismic tremor. 

Fountaining episodes have occurred approximately once per week since the start of the eruption on December 23, 2024. All eruptive activity remains within Hawaiʻi Volcanoes National Park. No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone. Current hazards include volcanic gas emissions and windblown volcanic glass (Pele’s hair) and tephra that have impacted Hawaiʻi Volcanoes National Park and nearby communities.

Announcement: 

Starting with episode 24, the Hawaiian Volcano Observatory began issuing a paired “Volcano Activity Notice (VAN)” and “Volcano Observatory Notice for Aviation (VONA)” (VAN/VONA) to announce the beginning and end of fountaining episodes. Our use of VAN/VONA replaced the Status Report notifications we had been issuing to announce the beginning and end of eruptive episodes. For more information see the Information Statement announcing this change in notification type: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2025-05-29T01:56:00+00:00. 

Summit Observations:

Episode 24 was preceded by sporadic spatter, gas pistoning, and hydrogen flames that began on the morning of June 3. At approximately 8:55 PM HST on June 4, episode 24 began with low dome fountaining accompanied by lava flows onto the crater floor. Small sustained lava fountains, less than about 100 feet (30 meters) high, began erupting from the north vent around 9:15 PM. Activity increased again around 10:10 PM, when fountain heights increased to 325 feet (100 meters) and by 10:40 reached over 1,000 feet (305 meters). Large lava flows erupted from both vents and covered about half of Halema'uma'u crater floor. 

The north vent stopped erupting at approximately 4:08 a.m. HST on June 5. The south vent stopped erupting at approximately 4:28 a.m. HST, marking the end of the episode. Lava flows from this episode on the floor of Halemaʻumaʻu within the southern part of Kaluapele (Kīlauea caldera) may continue to exhibit slow movement or incandescence as the cool and solidify over the coming days. 

Sulfur dioxide (SO₂) emissions were estimated at more than 50,000-75,000 tonnes per day (t/d). The eruptive plume reached at least 16,500 feet (5,000 meters) above ground level by 10:50 PM.

Episode 24 was accompanied by about 13 microradians of deflationary tilt at a tiltmeter near Uēkahuna (UWD), similar to the amount seen during episode 23. The end of the episode was coincident with a rapid change from deflation to inflation at the summit and a decrease in seismic tremor intensity. 

Summit tiltmeters recorded began recording inflationary tilt immediately following the end of episode 24. UWD has recovered less than one microradian of inflationary tilt in the 5 hours since the end of episode 24. Seismic tremor has returned to slightly elevated levels beneath Halemaʻumaʻu crater.

The average sulfur dioxide (SO₂) emission rate during inter-episode pauses is typically around 1,200 tonnes per day (t/d).

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.

• 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 are available here: Kīlauea Volcano, Hawaii (West Halemaʻumaʻu crater) v1cam, Kīlauea Volcano, Hawaii (East Halemaʻumaʻu crater) v2cam, and Kīlauea volcano, Hawaii (South Halemaʻumaʻu crater) v3 cam
• Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams 

The B2, KW, and F1 summit webcams are currently offline due to eruption impacts. Other HVO summit webcams are functioning and online.

Rift Zone Observations:

Rates of seismicity and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone with no significant earthquake activity in the past 24 hours. Sulfur dioxide (SO₂) emissions from the East Rift Zone remain below the detection limit.

Analysis: 

Additional time is needed to accumulate tiltmeter data before a forecast window can be made for episode 25. However, given that the deflationary tilt during episodes 24 and 23 was similar, we expect a roughly similar pause following episode 24. The pause between episodes 23 and 24 was 10 days. 

The current eruption has been characterized by episodic fountaining not seen in any eruptions since the 1983–86 episodic fountains at the beginning of the Puʻuʻōʻō eruption. Fountains and lava flows have erupted from two vents within Halema'um'a'u 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 have been accompanied by strong deflation of the summit region. Pauses between the fountaining episodes have been marked by an immediate change from deflation to inflation as the magma chamber recharges and repressurizes. Lava fountaining episodes have occurred approximately once per week since the start of the eruption. 

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 Hawaiʻi Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—are the primary 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/

Additional hazards include Pele's hair and other volcanic fragments from lava fountains. Pele's hair is strands of volcanic glass often produced by lava fountaining activity. Volcanic fragments can fall on the ground within a few hundred yards (meters) of the eruptive vent(s), or downwind of the vent(s). Strong winds may waft light particles, including Pele's hair, to greater distances downwind. Once they are 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 current wind conditions. Residents and visitors should minimize exposure to Pele's hair and other volcanic fragments, which can cause skin and eye irritation. More information about how Pele's hair forms, 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.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.

For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.