Activity Summary: The summit eruption at Kīlauea volcano that began on December 23 entered its fourth eruptive episode yesterday morning at about 9:15 a.m. H.S.T., and continues this morning. All eruptive activity remains confined 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 entered its fourth eruptive episode (Episode 4) yesterday morning at about 9:15 a.m. H.S.T. with a small sluggish lava flow exiting the north vent. Lava flow activity increase in rigor around 9:50 a.m., and lava fountaining began at north vent around 9:55 a.m. South vent became active around 11:40 a.m., also with lava fountaining and associated lava flows. Yesterday afternoon, field crews reported lava fountain heights of 90 to 100 meters (295 to 330 feet) from the north vent and 40 to 50 meters (130 to 160 feet) from the south vent. Both fountains were active overnight, with the north vent fountain consistently higher than the south vent. This morning, field crews reported lava fountain heights of 50 meters (160 feet) and 40 m (140 feet) from north and south vents, respectively. At about 8:25 a.m. this morning, field crews reported that parts of the south vent collapsed, with an associated reduction of about half in south vent lava fountain height. Lava flow activity has remained confined to the southwest crater floor area near the active vents. There are reports of Pele's hair falling on nearby communities, specifically the Volcano Golf Course subdivision, this morning (see Hazards section below).

Summit Instrumental Observations: Seismic tremor in the summit region increased rapidly yesterday around 9:40 a.m. H.S.T., and has remained high since, reflective of ongoing eruptive activity. Seismicity in the summit region remains low, with no earthquakes detected in the past 24 hours. Summit tiltmeters have recorded deflation starting around 10:15 a.m. yesterday morning. The most recently measured sulfur dioxide (SO₂) emission rate was approximately 560 tonnes per day Monday, January 14, before the start of Episode 4. It is estimated that the SO₂ emission rate was approximately 10,000 tonnes per day yesterday after the start of Episode 4; 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 been recorded neither sustained inflation nor deflation since January 3, 2025. 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. Vog information can be found at https://vog.ivhhn.org/.

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.