USGS Volcano Notice - DOI-USGS-HVO-2025-01-19T18:39:19+00:00

Activity Summary: The summit eruption at Kīlauea volcano that began on December 23 ended its fourth eruptive phase around 10:10 a.m. H.S.T. yesterday January 18. Glow from the vents and the crater floor has been persistent since as breakouts and overturning crustal plates expose molten lava. This indicates that lava remains close to the surface of Halemaʻumaʻu within Kaluapele (the summit caldera). No unusual activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.

Summit Eruption Observations: The summit eruption at Kīlauea volcano that began on December 23 ended its fourth eruptive phase around 10:10 a.m. H.S.T. yesterday January 18. Activity greatly decreased at approximately 9:45 a.m. when the north vent fountain and associated lava flow stopped erupting, and south vent activity greatly diminished at the same time. Lava continued to flow from south vent for another 20 minutes at a much reduced rate, and stopped erupting by 10:10 a.m. Since then, there has been glow from both vents, and from the crater flow as breakouts and overturning crustal plates expose molten lava. This indicates that lava remains close to the surface. Pele's hair formed in earlier stages of Episode 4 may continue to be remobilized by winds within the National Park and in nearby communities over the next few days (see Hazards section below).

Summit Instrumental Observations: Seismic tremor remains elevated during Episode 4, and abruptly ceased around 10:09 a.m. yesterday morning, returning to background levels within an hour. Seismicity in the summit region remains low, with only 2 small earthquakes (below M2.0) detected in the past 24 hours. Summit tiltmeters began recording inflation at about 9:50 a.m. yesterday, soon after fountaining activity ceased at the north vent, and have been steadily inflating since. The most recently measured sulfur dioxide (SO₂) emission rate was approximately 560 tonnes per day Monday, January 14, before the start of Episode 4, and could be analogous to current conditions. Though significantly lower than rates measured during eruptive Episodes 1, 2, and 3 (Kona winds precluded emission rate measurements during Episode 4), this value still represents above-background SO₂ emissions, and the resulting hazard will be affected by wind conditions (see Hazards section below).

View the Kīlauea summit eruption livestream: https://www.youtube.com/usgs/live.

January 15, 2025, Kīlauea summit eruption reference map: January 15, 2025—Kīlauea summit eruption reference map | U.S. Geological Survey.

Rift Zone Observations: Seismicity remains low in both the East Rift Zone and Southwest Rift Zone, with counts of shallow earthquakes at background levels. The ESC tiltmeter in the upper East Rift Zone has recorded minor inflation since the start of Episode 4 at the summit. Deformation rates remain low in the middle and lower East Rift Zone and in the Southwest Rift Zone, as recorded by GPS instruments and tiltmeters.

Analysis: The current eruption at the summit of Kīlauea is the sixth eruption since 2020 within Halema’uma’u crater, which sits inside the southern part of Kaluapele. The recent summit eruptions have lasted from one week to more than a year. Like most of the other eruptions, this event began with vigorous lava effusion and volcanic gas emissions from an initial fissure system. The current eruption is marked by episodic fountaining not seen in any of the other eruptions. There have been four fountaining episodes to date lasting from a few hours to over a week. The onset of fountaining of each episode is accompanied by strong deflation of the summit region. Pauses or periods of repose between all of the fountaining episodes are marked by an immediate change from deflation to inflation of the summit as magma recharge repressurizes the magma chamber. The prior four episodes all began after the Uēkahuna tiltmeter recorded between 6 and 12 microradians of inflationary tilt. The Uēkahuna tiltmeter has recorded about 2.5 microradians of inflationary tilt in past 24 hours and is currently inflating at a rate of 2 microradians per day. If this relatively high rate of inflationary tilt continues and magma remains high in the vent as indicated by strong glow at night, it suggests that there is a high probability that the fifth fountaining episode could begin sometime between Tuesday January 21 and Friday January 24. If the rate of inflation slows, the probable window of time for resumption of activity would be longer.

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/.

Pele's hair, which are strands of volcanic gas often produced by lava fountaining activity, can be carried by the wind. It 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. 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. Additional hazards include Pele's hair and other volcanic fragments from lava fountains that 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 lighter particles to greater distances downwind, and wind directions are variable. Residents and visitors should minimize exposure to these volcanic particles, which can cause skin and eye irritation.

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.