USGS Volcano Notice - DOI-USGS-HVO-2025-11-05T17:21:35+00:00

During the lapse in appropriations, the USGS Hawaiian Volcano Observatory (HVO) continues to maintain monitoring networks and issue updates and notifications of volcanic activity via the Hazard Notification Service. Volcano monitoring data will continue to be available on the HVO website. Static website content will not be updated until further notice and information may become outdated over time. For more information on the shutdown, please visit the Department of the Interior website at www.doi.gov.

Activity Summary:

Overflows of degassed lava continued from the south vent last night and grew in size and duration. While the north vent glowed intermittently overnight, all of the overflows have come from the south vent since just before 3 a.m. HST on October 4. Slow inflation of Kīlauea summit continued over the last 24 hours; however, repeated overflows from the north and south vents indicate the start of episode 36 is close. Models suggest a likely forecast window of November 5–8 for episode 36 with November 5-7 most probable.

Summit Observations:

The early morning hours were dominated by large overflows from the south vent that lasted up to 1 hour and 20 minutes.  During these events lava overflowed from all sides of the south vent cone and greatly enlarged the small channelized pāhoehoe flow field growing around the cone.  The last 3 events were the largest and longest lasting of the 14 overflows that have occurred since yesterday morningʻs update. These large overflows differed from the passive pond overflows of the previous events and instead had well developed hemispherical dome fountains 15-30 feet (5-10 meters) in diameter.  Both the passive pond overflows and the dome fountains had very little spattering until drainback, indicating that mostly degassed magma is being erupted at this time. The north vent glowed intermittently last night, but there were no standing lava or overflows since early yesterday morning, October 4.

The summit continues to inflate. The Uēkahuna tiltmeter (UWD) has recorded approximately 0.5 microradian of inflationary tilt over the past 24 hours and 25.7 microradians of inflationary tilt since the end of episode 35. Tremor patterns were consistent through most of the last 24 hours with periods of low tremor correlating with pond filling and/or overflows followed by short 5-10 minute tremor spikes related to drainback. That pattern changed just after 3 a.m. HST with much longer overflows (up to 1 hour 22 minutes) followed by long periods of higher tremor that decreased slowly over the next hour.

Plumes of gas continue from both vents this morning and sulfur dioxide (SO₂) gas emissions remain at background levels, typically between 1,200 and 1,500 tonnes per day. Yesterday wind conditions were favorable and the SO2 array southwest of the vent detected "puffs" of gas related to drainback events as is expected during gas pistoning events.

Episode 35 lava fountains began at approximately 8:05 p.m. HST on October 17 and ended at 3:32 a.m. HST on October 18. South vent fountains reached heights of nearly 1,500 feet (460 meters) and north vent fountains reached heights of about 1,100 feet (330 meters). These were the highest single fountain and highest pair of fountains seen during this eruption so far. Episode 35 fountains produced an estimated 13 million cubic yards (10 million cubic meters) of lava. The combined average eruption rate was over 500 cubic yards per second (400 cubic meters per second) from the dual fountains. Lava flows from the fountains covered about two thirds of the floor of Halemaʻumaʻu crater.

The following notices provide more information about episode 35:

• USGS Volcano Notice - DOI-USGS-HVO-2025-10-18T20:28:54+00:00
• USGS Volcano Notice - DOI-USGS-HVO-2025-10-18T10:16:28+00:00
• USGS Volcano Notice - DOI-USGS-HVO-2025-10-18T07:33:48+00:00
• USGS Volcano Notice - DOI-USGS-HVO-2025-10-17T05:15:25+00:00
• USGS Volcano Notice - DOI-USGS-HVO-2025-10-16T21:59:37+00:00

The following links provide more information about the current eruption that began on December 23, 2024:

• Eruption resources, including the most recent map and a timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
• Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://www.youtube.com/@usgs/streams
• Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams
• Volcano Watch article on gas pistons: https://www.usgs.gov/observatories/hvo/news/volcano-watch-so-what-earth-or-least-kilauea-a-gas-piston

Rift Zone Observations:

Rates of seismicity and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone, with no significant earthquake activity in the past 24 hours outside of the summit. SO₂ emissions from the East Rift Zone remain below the detection limit.

Analysis:

The immediate onset and continuation of inflationary tilt following the end of episode 35 coupled with persistent vent glow, spattering, and lava overflows indicate that the start of episode 36 fountains is close. Spattering is only associated with drainback events indicating the rising magma is still gas poor. Much larger volumes of lava have been erupted from the south vent yesterday as the gas-poor plug is pushed out of the vent, indicating the start of episode 36 is close.  The summit inflation rate remains slow and rose at a rate of about 0.5 microradians per day compared to 1 microradian per day yesterday. Models indicate episode 36 is currently likely to occur sometime between November 5 and November 8 with November 5-7 the most probable window.  

The current eruption has been characterized by episodic lava fountaining not seen in any eruptions since the 1983–86 episodic fountains at the beginning of the Puʻuʻōʻō eruption. Lava fountains and flows have erupted from two vents within Halemaʻumaʻu crater that we refer to as the north vent and south vent. Each of the previous fountaining episodes lasted from a few hours to over a week and was accompanied by strong deflation of the summit region. Pauses between the lava fountaining episodes have been marked by an immediate switch from deflation to inflation as the magma chamber recharges and repressurizes. Lava fountaining episodes have occurred approximately once per week since the start of the current eruption on December 23, 2024.

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:

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.