USGS Volcano Notice - DOI-USGS-HVO-2025-04-17T07:39:00+00:00

Activity Summary: 

Episode 18 of the ongoing Halemaʻumaʻu eruption began at 10:01 p.m. HST on April 16, 2025 when lava started overflowing from the north vent.

Episode 18 was preceded by glow from the south vent that increased at about 9:10 p.m. HST on April 16 and began regular spattering at 10-20 seconds apart. Spatter bursts continued to increase in size and frequency until about 9:30 p.m. HST when 10-15 foot high (3-5 meters high) dome fountains began. Lava level within the vent continued to rise until the lava pond became visible at 9:45 p.m. HST. Currently the eruption is feeding lava flows that extend down the north vent spillway and a short distance onto the Halemaʻumaʻu crater floor.

UWD tilt is relatively flat at this time but an increase in seismic tremor that began at 9:30 p.m. HST continues.

Emissions of SO₂ gas are elevated, and during recent episodes have reached 20,000 to 50,000 tonnes per day or more. Similar amounts of gas are expected to accompany any high fountaining activity that may occur during episode 17. 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 16.

Each episode of Halemaʻumaʻu lava fountaining since December 23, 2024, has continued for between 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 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, 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.