USGS Volcano Notice - DOI-USGS-HVO-2025-03-27T19:40:48+00:00

Activity Summary:  

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

Episode 15 of the ongoing Halemaʻumaʻu eruption ended abruptly last night after just over 31 hours, including about 9 hours of high fountaining. Fountaining associated with episode 15 reached heights over 1,000 feet (305 meters) at multiple times during the day yesterday; fountaining remained at or above 600 feet (180 meters) for most afternoon.

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:

Lava flows and fountains stopped erupting from the south vent within Halemaʻumaʻu crater at about 7:10 p.m. HST on March 26. Activity at the north vent had stopped hours earlier, around noon HST. Lava flows from episode 15 covered 80-90% of the Halemaʻumaʻu crater floor. Spots of orange glow can still be seen on the crater floor at night as the erupted lava continues to cool. The south vent continues to degas and glow at night, indicating magma remains at shallow levels in the vent. The north vent was largely infilled with tephra from the south vent, so vent glow was absent in the north vent last night aside from when minor slumping of the vent cone exposed still-hot material.

Tiltmeters at the summit recorded about 9 microradians of deflation at Uēkahuna (UWD) and 7 microradians of deflations at Sand Hill (SDH) during this episode. Initial deflation was very rapid, but slowed around noon HST when north vent activity ceased. The end of the eruption was coincident with a rapid change from deflation to inflation at the summit and a significant decrease in seismic tremor intensity to near zero. In the few hours following the end of the episode, about a dozen small seismic events occurred near the summit; following those events, variably weak seismic tremor has returned. In the past 14 hours, SDH and UWD tiltmeters have each recorded approximately 2 microradians of inflationary tilt since the end of episode 15.

Volcanic gas emissions remain elevated, though wind conditions yesterday and today have prevented acquisition of new emission rate data. Based on measurements made during earlier episodes and pauses, sulfur dioxide (SO₂) emission rates were likely around 50,000 t/d during yesterday’s high fountaining and are likely to be approximately 1,000 t/d during the current pause.

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 yesterday's daily update and 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 marked 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. The 15 fountaining episodes lasted from a few hours to over a week. Each fountaining episode 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.

Given that seismicity and tremor intensity are behaving somewhat differently after episode 15 compared to after previous episodes, and because there is less than 24 hours of tilt data since the end of the fountaining, the likely window for the start of the next episode remains uncertain at this time. 

• 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 yesterday’s high fountaining. 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 on the western caldera rim downwind of the vent(s). Strong winds may waft light particles to greater distances downwind. Once they are on the ground, they 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 these volcanic particles, which can cause skin and eye irritation. More information about how Pele's hair is formed is available here: https://www.usgs.gov/observatories/hvo/news/volcano-watch-peles-hairs-a-beautiful-hazard-island-hawaii. 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.