USGS Volcano Notice - DOI-USGS-HVO-2025-08-04T16:09:23+00:00

Activity Summary: 

Precursory eruptive activity for episode 30 of the Halemaʻumaʻu eruption began around 5:51 a.m. HST on Monday August 4 with short flows ending at 5:59 a.m. HST. Lava overflowed from the north vent at 5:51 a.m. HST and drained back with little spattering in the vent by 5:59 a.m. HST in a typical gas-pistoning cycle that produced short overflows. This had been preceded by an earlier gas-pistoning event with lava appearing at 5:14 a.m. HST and draining back with no lava flows and little spattering at 5:18 a.m. HST. It is unclear exactly when sustained eruptive activity may start, however, high lava fountaining is likely to begin today or tomorrow if summit inflation resumes.  Tilt at the summit has been weakly deflating since 4:00 a.m. HST after rising overnight.  According to the National Weather Service, winds are forecast to blow moderate trade winds from the north to northeast directions today, August 4th, which suggests that volcanic gas emissions and volcanic material may be distributed to the south and southwest. 

• All eruptive activity is confined to Halemaʻumaʻu crater within Hawaiʻi Volcanoes National Park; commercial airports in Hawaii County (KOA and ITO) will not be affected by this activity.
• Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: V1cam, V2cam, V3cam.
• KPcam and MKcam provide views of the plume height for aviation purposes.

In recent episodes of the ongoing eruption within Halemaʻumaʻu, low-level precursory activity has lasted from a few hours to a few days. This activity can include eruptive vent spattering, small dome fountains, and lava overflows.

At the start of previous episodes, precursory activity has rapidly escalated into sustained high fountaining over minutes to tens of minutes. During previous episodes, fountains reached heights of more than 1,000 feet (300 meters) and the eruptive plume reached heights of up to 20,000 feet (6,000 meters) above ground level soon after sustained high fountaining began.

The tiltmeter at Uēkahuna (UWD) has recorded just under 18 microradians of inflationary tilt since the end of the last episode, during which it recorded 19 microradians of deflationary tilt. Low level seismic tremor continues beneath Halemaʻumaʻu crater. 

Most episodes of Halemaʻumaʻu lava fountaining since December 23, 2024, have continued for around a day or less and have been separated by pauses in eruptive activity lasting generally at least several days. 

• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information.

No changes have been detected in the East Rift Zone or Southwest Rift Zone. A VAN/VONA will be issued when sustained high lava fountaining begins, marking the start of episode 30, or earlier if the situation warrants a further update.

Kīlauea Volcano Alert Level/Aviation Color Code remain at WATCH/ORANGE. All current and recent activity is within Hawaiʻi Volcanoes National Park.

Hazards: 

This episodic eruption is 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 one major 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/.

Another major hazard is fallout of Pele's hair and other volcanic fragments from lava fountains. Pele's hair is strands of volcanic glass often produced by lava fountaining activity that can be carried well over 10 miles (15 kilometers) from the vent. Other hot glassy volcanic fragments (tephra) including volcanic ash, pumice, scoria, and reticulite can fall on the ground within 1-3 miles (1-5 kilometers) of the eruptive vent(s), with the highest concentrations immediately downwind of the vent(s). Various volcanic fragments have fallen on Highway 11 west of Hawai'i Volcanoes National Park at times, depending on wind and eruption conditions. Strong winds may waft light particles, including Pele's hair, to greater distances downwind. Once 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 wind conditions. Residents and visitors should minimize exposure to Pele's hair and other glassy volcanic fragments, which can cause skin and eye irritation and can also contaminate catchment water supplies. 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 recently updated Frequently Asked Questions document that includes information about potential health effects of Pele's hair is available here: https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.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.