USGS Volcano Notice - DOI-USGS-HVO-2026-04-15T17:02:37+00:00

Overview:

The Halemaʻumaʻu eruption of Kīlauea is paused. Summit inflation is underway at this time, while glow and flames have been visible at south vent over the past day. Forecast models suggest that lava fountaining episode 45 will occur sometime between Sunday, April 19 and Saturday, April 25. Most Kīlauea monitoring data streams are operational again after HVO's radio telemetry network was restored yesterday afternoon.

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

For more information on the partial monitoring network outage that lasted from Saturday, April 11 until Tuesday, April 14, see the Information Statement here: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-04-12T15:47:48+00:00

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

Summit Observations:

Overnight, glow was consistently visible at the Halemaʻumaʻu south vent, along with several periods of intense flaming—likely caused by the ignition of volcanic gases escaping the vent. No such activity was apparent at the north vent, but it has continued to emit volcanic gases.

Low-level seismic tremor continues during the ongoing eruptive pause, with bursts approximately every 10 minutes likely associated with gas pistoning cycles in the north and south vents.

Since the end of lava fountaining episode 44 on April 9, the Uēkahuna tiltmeter (UWD) has tracked approximately 10.1 microradians of inflationary tilt. This instrument recorded 17.6 microradians of deflationary tilt in total during the episode.

With the eruption paused, the sulfur dioxide (SO₂) emission rate from Halemaʻumaʻu is likely now varying within a typical range of 1,000 to 5,000 tonnes per day. Winds near the eruptive vents have been directionally variable over the past day.

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 the 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 inflation indicate that episode 45 lava fountains are likely to occur sometime between Sunday, April 19 and Saturday, April 25.

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 44:

Episode 44 ended at 7:41 p.m. HST on April 9 after 8.5 hours of continuous lava fountaining from the north vent, sending tephra to the north into public areas of Hawai'i Volcanoes National Park and into surrounding communities. UWD tiltmeter recorded 17.6 microradians of deflationary tilt during the episode.

A full summary of episode 44 can be found in a Status Report here: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-04-10T06:25:16+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 south 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.