USGS Volcano Notice - DOI-USGS-HVO-2025-03-20T16:45:31+00:00

Activity Summary:  

Episode 14 of the ongoing Halemaʻumaʻu eruption began at 9:26 a.m. HST on March 19 with continuous lava effusion from the north vent. Both vents are currently active with large fountains reaching 400-600 ft (100-200 m). The south vent began sustained fountaining around 6:30 a.m. HST on March 20 followed by sustained fountains in the north cone at 6:50 a.m. HST. The north cone shut off at 7:46 a.m. HST, and the south cone fountains have reached heights up to 500-700 feet (150-215 m).

Episode 14 was preceded by seven small, short-lived lava flows that began at approximately midnight on March 19 and continued until 6:02-6:10 a.m. The onset of the continuous eruption with cyclic low lava fountaining (30 ft high) and drainback events of the lava pond extended from 9:26 a.m. HST March 19 through this morning with increased intensity at 2:00 a.m. HST March 20. Sustained fountaining from both cones began around 6:30 a.m. HST on March 20. 

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.

Kīlauea's current eruption in Halemaʻumaʻu crater within Kaluapele (the summit caldera) began on December 23, 2024. There have been 13 episodes of lava fountaining separated by pauses in activity. Episode 13 ended at 3:13 p.m. HST on March 11. 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.

Summit Observations:

Small, degassed lava flows began erupting continuously from both vents within Halemaʻumaʻu crater beginning at 9:26 a.m. HST from the north vent and 9:50 a.m. HST from the south vent on March 19. The occasional spatter bursts in both cones slowly waned throughout the morning after 7:00 a.m. HST, but activity in both cones picked back up around 9:20 a.m. HST just prior to the start of continuous eruption. The south vent flows became sporadic around 10:35 a.m. HST.  Cyclic low dome fountains alternated with short drainbacks in the north vent every 5-10 minutes with the interval decreasing over time.  Maximum dome fountains were 30 feet high (10 meters) and occurred within a 200 foot by 150 foot  (65 by 45 meters) lava pond that drops about 5-10 feet (2-3 meters) during each drainback event within the north cone.  The size of the dome fountains increased significantly around 2:00 a.m. HST March 20th with fountain heights reaching 50-100 feet (15-30 m).  At 6:30 a.m. the south vent started to fountain continuously and was joined by the north vent at 6:50 a.m. HST.  By 7:15 a.m. HST fountains reached heights of 400-600 feet (120-180 meters) and lava was covering more than half of Halema'uma'u crater floor.

Prior to start of continuous eruptions, episode 14 was preceded by seven small, short-lived, sluggish lava flows that began overflowing the south vent just before midnight. The first flow was active from 23:58 p.m. HST March 18 to 00:02 a.m. HST March 19 and the second from 00:56 to 1:03 a.m. HST. These were followed by a third tongue of lava from the south vent from 1:57 to 2:01 a.m. HST and a fourth from 3:36 to 3:46 a.m. HST.  The fifth and sixth sluggish lobes erupted from 4:20 a.m. to 4:28 a.m. HST and 5:04 to 5:14 a.m. HST. A seventh short-lived flow erupted from the south vent between 6:02 a.m. and 6:10 a.m. HST March 19. This flow was accompanied by large spatter bursts from the south vent that could be seen over the top of the north cone on the V1 camera. None of the seven flows lasted more than 10 minutes nor went more than about 50 feet (15 meters) from the south vent. Occasional spatter bursts could be seen in the north vent on the V1 camera throughout the night and becoming more frequent in the early morning hours.  

The rate of summit inflationary tilt slowed over past 24 hour until the onset of high fountaining after 6:30 a.m. HST. Inflationary tilt recovered 12 microradians since the end of the last episode. Seismic tremor rapidly increased at 6:30 a.m. HST and tilt at UWD switched from inflation to deflation at about 6:52 a.m. HST, when sustained fountaining of the north vent joined with the south vent. 

An SO₂ emission rate of 1,200 t/d was measured on March 18, which is a typical rate for eruption pauses. Emissions of SO₂ during the current high fountains will be in the 20,000 to 50,000 tonnes per day range based on past measurements.  The fountains are also currently producing tephra such as pumice and Pele's hair that can be transported long distances downwind from the vents.

• Summit eruption livestream: https://www.youtube.com/usgs/live
• 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 13 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.

• 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.

Hazards: 

The eruption has been 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. 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.