Activity Summary: The summit eruption at Kīlauea volcano that began on December 23 entered its fourth eruptive episode on January 15 and continues this morning. All eruptive activity remains confined within Kaluapele (the summit caldera), although persistent fountaining coupled with Kona winds has resulted in Pele's hair reported in some public areas within the National Park and in nearby communities. 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 entered its fourth eruptive episode (Episode 4) the morning of January 15, and continues. Activity is concentrated at two lava fountains in southwest Kaluapele that have each built up a cone and have associated lava flows. As of this morning, both cones are 30 to 35 meters tall (100 to 115 feet), and field crews report that the current fountaining is generally the height of the cones, with occasional fountaining to 40 to 45 meters (130 to 150 feet). There have been lava ooze-outs overnight on the crater floor in areas that covered by lava during earlier episodes of the current eruption. Over the past 24 hours, persistent lava fountaining, coupled with Kona wind conditions, has resulted in Pele's hair falling on nearby communities, along with tephra fall at Uekahuna Overlook and within the closed area of the National Park. There have been reports of Pele's hair near Uekahuna Overlook, the Kīlauea Visitor's Center, the Volcano Golf Course subdivision, Volcano Village, and Ohia Estates; other areas and communities may also be affected (see Hazards section below).

Summit Instrumental Observations: Seismic tremor remains elevated during this period of lava fountaining but has remained constant over the past 24 hours. Seismicity in the summit region remains low, with only 1 small earthquake (below M2.0) detected in the past 24 hours. Summit tiltmeters continue to record deflation, which started soon after the start of Episode 4. The most recently measured sulfur dioxide (SO₂) emission rate was approximately 560 tonnes per day Monday, January 14, before the start of Episode 4. Current Kona wind conditions are not favorable for obtaining accurate SO₂ emission rate measurements. Emissions during the current fountaining are likely to be on the order 10,000 tonnes per day or more; 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 within Kaluapele since 2020. These eruptions in the summit region have lasted from one week to more than a year in duration. Like most of the other eruptions, this event began with vigorous lava effusion and volcanic gas emissions, but it has paused three times and is now in Episode 4. Episodes 2, 3, and 4 of this eruption were preceded by re-inflation of the summit. Summit eruptions observed over the past 60 years have exhibited vigorous activity in the opening days which can episodically wax and wane, or drop over time to more sustainable low effusion rates, or slowly diminish and end.

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. Kona winds, the current wind condition preventing gas emissions measurements, also tend to cause vog around Hawaii Island, including in Hilo and the Hamakua coast. A return to weak trade winds is forecast for this weekend. 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.