USGS Volcano Notice - DOI-USGS-HVO-2025-07-19T03:11:59+00:00

Activity Summary: 

Precursory low-level activity for episode 29 of the ongoing Halemaʻumaʻu eruption began around 3:55 a.m. HST on July 20 with spattering at the north vent, followed shortly thereafter by dome fountains and lava overflows starting around 4:11 a.m. HST. Sustained, high lava fountaining may begin soon. According to the National Weather Service, winds are forecast to blow from the north to northeast directions today, Sunday, July 20, 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. Due to the heightened level of pressurization reached during the most recent eruptive pause, precursory activity for episode 29 may be brief, and sustained, high lava fountaining may begin soon.

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 approximately 17.8 microradians of inflationary tilt since the end of the last episode, during which it recorded 15 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 29, 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 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 hazard closer to the vent 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 and can be carried well over 10 miles (15 kilometers) from the vent. Other hot glassy volcanic fragments including Peleʻs hair, volcanic ash, pumice, scoria, and reticulite can fall on the ground within 1-2 miles (1-3 kilometers) of the eruptive vent(s) with the highest concentrations downwind of the vent(s). Pumice and other volcanic fragments have fallen on Highway 11 west of Hawaiʻi Volcanoes National Park depending on wind and eruption conditions.  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 glassy volcanic fragments, which can cause skin and eye irritation. 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.