USGS Volcano Notice - DOI-USGS-HVO-2025-03-28T18:57:56+00:00

Activity Summary:  

The summit eruption of Kīlauea, within Halemaʻumaʻu, is paused as of March 26, at 7:10 p.m. HST.

Kīlauea's current eruption in Halemaʻumaʻu crater within Kaluapele (the summit caldera) began on December 23, 2024. There have been 15 episodes of lava fountaining separated by pauses in activity. All eruptive activity remains within Hawai'i 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 Hawai’i Volcanoes National Park and nearby communities.

Summit Observations:

Episode 15 ended on March 26, 2025. Spots of orange glow can still be seen on the crater floor at night as the erupted lava continues to cool. 

The condition of the vents after episode 15 appears substantially different than after the previous eruptive episodes. A small opening in the south vent continues to degas and glow weakly at night. The north vent was inactive for much of the high fountaining of episode 15 and was largely infilled with tephra and spatter from the south vent, so vent glow is essentially absent at the north vent. It may be that the north vent, and to a lesser extent the south vent as well, has become somewhat blocked or sealed by erupted material from episode 15. Overall, vent glow is substantially less than following previous episodes.

Tiltmeters at the summit recorded about 9 microradians of deflation at Uēkahuna (UWD) and 7 microradians of deflations at Sand Hill (SDH) during episode 15. Since the current pause began, SDH and UWD tiltmeters have each recorded approximately 3.5 microradians of inflationary tilt.

Immediately following the end of fountaining on March 26, seismic tremor decreased to near zero. Intermittent tremor returned yesterday (March 27), though at lower levels than during earlier pauses. Tremor has since weakened further, though it is still present.

Volcanic gas emissions likely remain elevated above background, though possibly at lower levels than during other pauses. SO₂ emission rates during previous pauses were approximately 1,000 t/d. Wind conditions and widespread vog continue to prevent updated emission rate measurements. Note that today's voggy conditions are the result of weak winds allowing the very high levels of gas emissions from episode 15 to linger over the area, rather than because of current levels of gas emissions.

Strands of volcanic glass known as Pele’s Hair, as well as small chunks of tephra, have been reported on surfaces throughout the summit area of Hawai’i Volcanoes National Park and surrounding communities. 

• Additional information about episode 15 can be found in daily updates from March 26 and March 27, as well as in status reports from the onset of fountaining and the end of the episode
• Timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information 
• Two Kīlauea summit livestream videos are available here: Kīlauea Volcano, Hawaii (West Halemaʻumaʻu crater) v1cam and Kīlauea Volcano, Hawaii (East Halemaʻumaʻu crater)v2cam
• Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams 

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 detection limit.

Analysis: 

The current eruption is characterized by episodic fountaining not seen in any of the other Halemaʻumaʻu eruptions since 2020. Fountains and lava flows have erupted from two vents that we refer to as the north vent and south vent. Each of the 15 fountaining episodes lasted from a few hours to over a week and has 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.

The current pause has followed the same pattern of reinflation as other pauses. However, other observations have indicated some differences with this pause. The short increase in small earthquakes immediately following episode 15, the significant drop in tremor, and the diminished glow at the vents may indicate that the vents are blocked or partially blocked. A blocking, or sealing, of the vents could partially suppress degassing and thus limit degassing-induced tremor. 

The continued inflation of the summit recorded on both the UWD and SDH tiltmeters indicates that magma is being replenished at a rate similar to that seen during prior pauses. Another episode is likely to take place if magma can overcome any blockage of the conduit. Current rates of inflation indicate that a new episode could begin between Monday, March 31, and Wednesday, April 2, if the conduit is re-opened. If additional pressure is required to re-open the conduit, the eruption re-start window could be delayed, or the eruption could end. 

• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
• Summit eruption reference map: January 15, 2025—Kīlauea summit eruption reference map | U.S. Geological Survey
• Volcano Watch article about Pele's Hair from this eruption: https://www.usgs.gov/observatories/hvo/news/volcano-watch-recent-lava-fountains-highlight-peles-hair-hazards

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.

General Updates: 

The power system that supplies power to the KWcam webcamera, the F1cam thermal camera, and the laser rangefinder sustained damage during the high fountaining on March 26, 2025. Both cameras and the rangefinder are currently offline. Other HVO webcameras are still functioning and online.

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 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 are 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 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, 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 Frequently Asked Questions document developed for the 2022 Mauna Loa eruption includes information about potential health effects of Pele's hair and is available here: https://vog.ivhhn.org/sites/default/files/FAQ_on_air_quality_and_health_during_Mauna_Loa_eruption_v1.6.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.