USGS Volcano Notice - DOI-USGS-HVO-2025-05-06T17:34:37+00:00

Activity Summary:

Episode 20 low-level precursory activity began on May 5 at 10:48 a.m. HST. Episode 20 sustained lava fountaining is likely to start between now and tomorrow. 

Kīlauea's current eruption in Halemaʻumaʻu crater within Kaluapele (the summit caldera) began on December 23, 2024. There have been 19 episodes of sustained lava fountaining separated by pauses in activity. All eruptive activity remains within Hawaiʻi 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 Hawaiʻi Volcanoes National Park and nearby communities.

Summit Observations:

Episode 20 low-level precursory activity began yesterday morning, May 5, at 10:48 a.m. HST, with the onset of cyclic gas-pistoning events in the north vent. These cycles included lava dome fountaining followed immediately by lava draining back into the vent. About 30 gas-pistoning cycles occurred sequentially between 10:49 a.m. and 6:00 p.m. yesterday. This period of continuous cycling diminished after 6:00 p.m. and was followed by a period of intermittent gas-pistoning that is ongoing at the time of this report. Lava has overflowed the north vent during many of these events, producing short lava flows. A short lava flow also erupted from the south vent onto the crater floor yesterday, starting at about 11:23 a.m. Strong glow was visible from both vents overnight.

Episode 20 low-level precursory activity has been less consistent than episode 19 precursory activity. The main fountaining phase of episode 19 was preceded by 26 gas-pistoning cycles that occurred sequentially over a period of 9 hours. In comparison, episode 20 precursory activity has lasted approximately 22 hours so far, and has included cyclic as well as intermittent gas-pistoning events. Based on current levels of activity, the main fountaining phase of episode 20 is likely to start between now and tomorrow.

The UWD tiltmeter has recorded about 6.5 microradians of inflation since the end of episode 19. A sulfur dioxide (SO₂) emission rate measured on May 2 was approximately 1,750 tonnes per day, which is typical during the eruption pauses. Strands of volcanic glass known as Pele’s hair from previous episodes are still present throughout the summit area of Hawaiʻi Volcanoes National Park and surrounding communities, and can be remobilized by wind.

• 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 

The B2cam, KWcam, and F1cam summit webcams are currently offline. Other HVO summit webcams are functioning and online.

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 the detection limit.

Analysis: 

The current eruption has been characterized by episodic fountaining not seen in any eruptions since the 1983-86 episodic fountains at the beginning of the Puʻuʻōʻō eruption. Fountains and lava flows have erupted from two vents that we refer to as the north vent and south vent. Each of the previous 19 fountaining episodes lasted from a few hours to over a week and have 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.

The rapid rebound of recorded UWD and SDH tilt from deflation to inflation at the end of episode 19, along with ongoing cycles of low-level fountaining, indicate that another episode of sustained fountaining is likely. Data indicate that episode 20 is likely to start between now and tomorrow, Tuesday to Wednesday this week.  As more data becomes available, the window may be adjusted.

• 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: 

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 forms, 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.