Activity Summary: 

Episode 15 of the ongoing Halemaʻumaʻu eruption began at 12:04 p.m. HST on March 25 with the onset of vigorous overflows from the north vent and is continuing cycles of lava rise, fountaining and vigorous overflows, and drainback events.  No high fountaining has occurred during this episode as of the time of this update.

Episode 15 was preceded by eight cyclic, small spatter fountains in the north vent that began at approximately 9:27, 9:55, 10:11, 10:29, 10:48, 11:07, 11:27, and 11:45 a.m. HST on March 25 and lasted for 5-10 minutes each.  The ninth cycle lasted from 12:04-12:19 p.m. HST and produced vigorous overflows that extended 150 to 300 feet (50-100 meters) into Halemauʻamaʻu crater.  Activity increased in activity with subsequent events from at 12:25-12:39, 12:47-13:02,13:08-13:23, 3:29-13:39, and 13:46- 13:58 p.m. HST. These continued to increase in intensity with fountains up to 30-50 feet high (10-15 meters) from the north vent.  Around noon, the south vent also became active and is feeding a lava flow out onto the crater floor.  Flows from both vents have covered about 5% of the floor of Halemaʻumaʻu crater at this time.  High fountaining has not yet begun, but is expected to follow the cyclic fountains and drainbacks as it did during episode 14.

Inflationary tilt reached just over 5 microradians since the end of the last episode recovering more than 100% of the tilt lost from episode 14. Seismic tremor began increasing with cyclic fountains and drainbacks, and tilt at SDH switched from inflation to deflation at about 1 p.m. HST, about the same time lava flows began erupting onto the crater floor. 

Emissions of SO2 gas during episodes 13 and 14 have exceeded 40,000 tonnes per day and similar amounts of gas are expected to accompany fountain eruptions during episode 15.  Currently winds at the summit are predicted 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 towns may be exposed to Peleʻs hair and other small fragments of volcanic glass being carried in the plume.

Each episode of Halemaʻumaʻu lava fountaining since December 23, 2024, has continued for 13 hours to 8 days, and episodes have been separated by pauses in eruptive activity lasting less than 24 hours to 12 days. 

• 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

No changes have been detected in the East Rift Zone or Southwest Rift Zone. HVO continues to closely monitor Kīlauea and will issue an eruption update tomorrow morning unless there are significant changes before then. 

Kīlauea Volcano Alert Level/Aviation Color Code remain at WATCH/ORANGE. All current and recent activity is within Hawaiʻi Volcanoes National Park.

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. Vog information can be found at https://vog.ivhhn.org/.

Additional hazards include Pele's hair and other volcanic fragments from lava fountains that can fall on the ground downwind of the eruptive vent(s). Pele's hair are strands of volcanic glass produced by lava fountaining activity. Strong winds may waft these light particles to greater distances downwind. Pele's hair can sometimes cluster and tangle together on the ground, 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 and the southwest side of Kaluapele, Kīlauea's summit caldera. 

Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu 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, an area that has been closed to the public since late 2007.