USGS Volcano Notice - DOI-USGS-HVO-2026-04-10T06:25:16+00:00

Activity Summary: 

• Episode 44 of the ongoing Halemaʻumaʻu eruption ended abruptly at 7:41 p.m. HST on April 9, 2026, after 8.5 hours of continuous lava fountaining. The eruption is currently paused.

• Tephra fell outside of the closed area of Hawaiʻi Volcanoes National Park along the north rim of Kaluapele (Kīlauea caldera) and in adjacent communities. Tephra as large as 10 inches (25 centimeters) was reported in the Volcano Golf Course subdivision, and fine ash and Peleʻs hair was reported as far away as Hilo. 

   

Episode 44 Chronology:

Episode 44 lava fountaining stopped at 7:41 p.m. HST on April 9, 2026, after 8 hours and 31 minutes of continuous lava fountaining from the north vent. The south vent never fountained during this episode, but it displayed periodic gas jetting and flames. The highest peak or instantaneous effusion rate of just over 500 cubic yards (390 cubic meters) per second occurred around 12:30 p.m. HST on April 9. Episode 44 saw an average effusion rate of 260 cubic yards (200 cubic meters) per second, with an estimated 7.5 million cubic yards (5.8 million cubic meters) of lava erupted and covering about 50% of the Halemaʻumaʻu crater floor. The Uēkahuna tiltmeter (UWD) recorded about 17.6 microradians of deflationary tilt during episode 44.

Episode 44 lava fountaining began at 11:10 a.m. HST on April 9, 2026, almost a week after the onset of precursory lava overflows on April 3. There were approximately 75 precursory overflows from April 3 to the start of episode 44 lava fountaining on April 9. Only 4 precursory overflows originated from the north vent, all on the morning of April 9. The last of these began at 10:08 a.m. HST and erupted continuously until transitioning into the onset of episode 44 at 11:10 a.m. HST. The start of episode 44 was marked by a sharp increase in seismic tremor and deflationary tilt recorded at the Uēkahuna tiltmeter (UWD). At first, the north vent grew slowly to about 330 feet (100 meters) in height by 12:00 p.m, then it reached a maximum of about 800 feet (240 meters) by 12:45 p.m. HST. Afterwards it gradually dropped, and by 4:00 p.m. it was 500 feet (150 meters) in height, then it further diminished until the end of the episode at 7:41 p.m. HST.

The single lava fountain produced significant heat and ash, feeding a plume that reached a maximum height of about 15,000 feet (4,500 meters) above sea level by 1:30 p.m. HST. Southerly winds directed the plume and tephra fall to the north of Halemaʻumaʻu.

This eruption was much smaller in size than episodes 41–43, but due to steady winds it produced a tephra fallout pattern similar to but not as thick as episode 43. The plume deposited tephra within Hawaiʻi Volcanoes National Park near Kīlauea Military Camp and into the adjacent Volcano Golf Course subdivision.

Alert levels were raised from ORANGE / WATCH to RED / WARNING by the USGS Hawaiian Volcano Observatory at 12:36 p.m. HST reflecting potential hazards to surrounding communities and aviation. Highway 11 through Volcano and the Kīlauea section of Hawaiʻi Volcanoes National Park were closed due to the hazards. The National Weather Service issued an ashfall WARNING at 12:40 p.m. HST following an earlier ashfall advisory. Ash and Pele’s hair was reported as far away as Kaumana, just west of Hilo.

Resources:

• Additional short messages during episodes: https://www.usgs.gov/observatories/hvo/observatory-messages   
• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information 
• Three Kīlauea summit livestream videos: https://www.youtube.com/@usgs/streams 
• Report tephra fall: https://hawaiiash.science/report_form 
• Hawaiʻi Volcanoes National Park Information https://www.nps.gov/havo/planyourvisit/conditions.htm
• County of Hawaii Hazard Impact Map: https://www.arcgis.com/apps/dashboards/5865229bcba74020992b372ef18b6f17

Hazard Analysis: 

• Volcanic Gas: Water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂) are continuously released during an eruption. SO₂ reacts in the atmosphere to create the visible haze known as vog (volcanic smog) downwind, which may cause respiratory and other problems. 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 the links below:
  • https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/  
  • https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.pdf

• 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 exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the 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.