USGS Volcano Notice - DOI-USGS-HVO-2026-05-31T16:35:22+00:00

Overview:

There have been 29 precursory eruptions of sluggish lava from the south vent within Halemaʻumaʻu since they began at 5:41 p.m. HST on May 30. Spattering continues from the north vent, but no overflows at this time. The forecast for the onset of episode 48 fountaining is between today and tomorrow (May 31-June 1), with today more likely. There is potential for ashfall into surrounding communities from this episode; see below.

No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.

NOTE: The National Weather Service (NWS) has issued a Special Weather Statement regarding the potential for ash fall to the SW and NE of the summit of Kīlauea volcano.  The statement can be found here: WWA Summary by Location for 19.69N 155.5W with HIZ027/HIC001/HIZ342 emphasis Special Weather Statem…

NOTE: Hawaii County Civil Defense Agency (HCCDA) has issued a message about the potential for ashfall alerting residents to prepare by closing windows and protecting catchment water supplies: https://evb.gg/n#lyhnndpyubk/0kFQoa2q

NOTE: Significant changes in activity between Daily Updates are posted here: https://www.usgs.gov/observatories/hvo/observatory-messages

Summit Observations:

Precursory overflows of degassed lava began from the south vent at 5:41 p.m. HST yesterday May 30. The overflows are generally small and stay within a few hundred meters of the vent. There have been 29 overflows so far that typically last 5-10 minutes and are spaced 15-30 minutes apart. Low dome fountains (5-10 ft or 1-3 m high) feed the passive overflows. The end of events is marked by vigorous drainback of lava and a drop in lava level within the vents. Spattering continued throughout the night building the small cone within the north vent. The vigor of spattering within the north vent greatly increased around 7:51 a.m. HST this morning (May 31) and lava appears to be coming out of the back wall vent and draining into the main vent. No precursory overflows have occurred from the north vent.

Seismic tremor continues but changed to well -efined gas pistoning with the first overflow. Low tremor characterizes the overflow followed by a sharp increase associated with drainback of lava. Earthquake activity beneath Kīlauea summit remains low with 6 earthquakes located around Halemaʻumaʻu in the last 24 hours. The largest was a magnitude 1.83 at 6:53 a.m. HST today (May 31) in the center of Halemaʻumaʻu.

Kīlauea summit inflation continues very slowly this morning, after flattening out with the onset of the first overflow. Since the end of lava fountaining episode 47 on May 15, the Uēkahuna tiltmeter (UWD) has tracked about 17 microradians of inflationary tilt (a small tilt offset was due to the M6 earthquake on the west side of the island on Friday evening). This instrument recorded 15.6 microradians of deflationary tilt during episode 47.

With the eruption now paused, the sulfur dioxide (SO₂) emission rate from the summit is likely now varying within a typical range of 1,000 to 5,000 tonnes per day. Measurements on Friday, May 22, indicated emission rates of about 2,000 tonnes per day. Surface winds are out of the northeast at the summit this morning with higher level winds forecast out of the west southwest. See the NWS Special Weather Service message linked at the top of this message.

Rift Zone Observations:

Rates of seismicity and ground deformation remain low in the East Rift Zone and Southwest Rift Zone. SO₂ emissions from the East Rift Zone remain below the detection limit.

Analysis:

The rapid return of inflationary tilt and glow from both Halemaʻumaʻu eruptive vents indicates that another lava fountaining episode is likely. Lava spattering and overflows from one or both of the eruptive vents are expected to precede the next lava fountaining episode. Forecast models based on summit tilt are no longer valid. Seismic velocity models indicate that episode 48 fountains are most likely between this afternoon and Monday (May 31-June 1). The forecast window may change as more data are incorporated into the models or additional events occur.

Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. Lava fountaining episodes, which generally last for less than 12 hours, are separated by pauses that can be longer than three weeks.

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

Recap of episode 47:

Episode 47 ended abruptly at 12:27 a.m. HST on May 15 after 9 hours of continuous lava fountaining from the north vent. The eruptive plume sent light tephra into public areas of Hawai'i Volcanoes National Park and surrounding communities to the northeast. UWD tiltmeter recorded 15.6 microradians of deflation during the episode.

A full summary of episode 47 can be found in a Status Report here: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-05-15T10:42:06+00:00

Resources:

NOTE: HVO’s monitoring network is mostly recovered from recent power- and storm-related outages. Several summit stations, including the SDH tiltmeter, will remain offline until we are able to re-establish access across the deep tephra field southwest of the caldera.

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
• Short messages tracking the evolution of the lava fountains and eruptive activity can be found here: https://www.usgs.gov/observatories/hvo/observatory-messages
• Three Kīlauea summit livestream cameras 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

Hazards:

This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park.

• Volcanic Gas: high levels of volcanic gas—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—are continually released during an eruption. Emissions can remain locally hazardous in the areas immediately downwind of the vents, even when the vents are not actively erupting. SO₂ reacts in the atmosphere to create vog (volcanic air pollution) downwind. SO₂ and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/
• Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
• Lava flows: lava on the floor of Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera, remains hot and may slowly move in the days immediately following an eruptive episode.

Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the eruptive vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. 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.