USGS Volcano Notice - DOI-USGS-HVO-2025-04-01T18:47:47+00:00

Activity Summary:  

Episode 16 of the ongoing Halemaʻumaʻu eruption at Kīlauea's summit began at 10:57 p.m. HST yesterday, March 31, 2025, with overflows from north vent. Current activity includes low (15-25 feet, or 5-7 meters) dome fountains and spatter in the north vent, with continued lava flows. High fountaining is expected to follow this period of low-level activity, as has occurred in previous episodes.

Kīlauea's current eruption in Halemaʻumaʻu crater within Kaluapele (the summit caldera) began on December 23, 2024. There have now been 16 episodes of various degrees of 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:

Despite diminished tremor and glow during the pause following episode 15, episode 16 began at 10:57 p.m. HST yesterday, March 31, 2025. The status update from the start of the eruption can be found here.

The first signs of renewed activity were the reappearance of low spatter in the north vent and tremor, yesterday (March 31) evening at around 5:20 p.m. HST. Around 6 p.m. HST, spattering became continuous and increased to low dome fountaining (15-30 feet or 5-10 meters high). Lava level gradually rose in the vent and began flowing out of the north vent cone onto the floor of Halemaʻumaʻu at 10:57 p.m. HST to start the eruption. The south vent was glowing overnight as well and currently has a small degree of spattering within it. No gas pistoning – cyclic draining behavior that occurred in both episode 14 and episode 15 – has not been noted thus far in episode 16. Flows from this episode are still small and have covered less than 5% of the floor of Halemaʻumaʻu crater as of this update.

Each of the prior 15 episodes ultimately involved significant lava fountaining, with the fountains of episode 15 exceeding 1,000 feet (305 meters) in height. High lava fountains are likely to follow the current dome fountaining and lava flows within 24 hours or less.

Inflationary tilt on the UWD tiltmeter reached around 8 microradians since the end of the last episode, recovering about 90% of the tilt lost from episode 15. UWD tilt has been flat since about the time that lava spattering began, but it has not started deflating at this time. Seismic tremor and infrasound have been elevated and steady since the eruption began last night.

Volcanic gas emissions remain elevated. During recent episodes, SO₂ emission rates have reached 50,000 tonnes per day or more, and similar amounts of gas are expected to accompany any high fountaining activity that may occur during episode 16. Currently, winds at the summit are forecast to be weak, which may allow the plume of gas to spread around the summit region of Kīlauea. In addition, visitors to Hawaiʻi Volcanoes National Park and residents of adjacent areas may be exposed to Peleʻs hair and other small fragments of volcanic glass and tephra being carried in the plume, as they were during episode 15.

Strands of volcanic glass known as Pele’s Hair from previous episodes are still present throughout the summit area of Hawai’i Volcanoes National Park and surrounding communities. 

• 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 has been 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 previous 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.

Analysis of inflationary tilt patterns prior to the onset of each fountaining episode allows a time window of probability for the onset of new episodes to be estimated. These are calculated using both minimum inflation necessary to start a new eruption and the rate of inflation fit to data derived from past eruptive episodes. Episode 16 began yesterday slightly ahead of the expected window of time in spite of diminished glow and tremor after the previous episode. 

Based previous episodes, we expect that the low dome fountains will transition to high lava fountaining today, April 1, 2025. General eruptive behavior and timing for this episode, as well as the degree of deflation during the activity, will dictate forecasts and expectations for activity beyond the current episode.

• 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 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, 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.