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Episode 16 of the ongoing eruption in Halemaʻumaʻu stopped just after noon today, April 2, 2025. On a USGS Hawaiian Volcano Observatory monitoring overflight within the hours following its end, the crater floor was a patchwork of active and inactive lava flows.

During a monitoring flight on April 2, 2025, USGS Hawaiian Volcano Observatory geologists captured this aerial view of Halemaʻumaʻu, within Kaluapele (Kīlauea summit caldera), just after the end of episode 16 of the ongoing eruption.

During each eruptive episode in Halemaʻumaʻu, tephra is deposited on the crater rim downwind within the closed area of Hawaiʻi Volcanoes National Park. This sign for the Southwest Rift Zone of Kīlauea, which used to stand at least 6 feet (2 meters) above the ground surface, provides a visual for how thick the tephra deposit is at this location. USGS photo by K.

On April 1, lava fountains from Kīlauea's ongoing summit eruption prevented geologists from accessing the rim of Halemaʻumaʻu crater within the closed portion of Hawaiʻi Volcanoes National Park. Instead, they hung back along the closed portion of Crater Rim Drive to collect samples of tephra that was intermittently blown in their direction.

Episode 16 lava fountains were visible from Highway 11 in Kaʻū on April 1. In this view, the top of the lava fountain is just visible above Halemaʻumaʻu crater rim, and Uēkahuna (the highest part of the caldera rim) is visible to the left. USGS photo by K. Mulliken. 

Episode 16 lava fountains deposited tephra and Pele's Hair on Highway 11 in Kaʻū on April 1. In this photo, taken around 3:30 p.m. HST, the tephra and Pele's Hair is visible along the centerline and on the shoulder of the highway. USGS photo by K. Mulliken. 

The episode 16 eruption plume was transported north-northwest on April 1, over Highway 11 in Kaʻū. USGS Hawaiian Volcano Observatory volcanic gas specialists traversed under the plume on the highway in order to get a sulfur dioxide emission rate for episode 16.

Wind conditions during episode 16 of the Kīlauea summit eruption resulted in material from the lava fountains being deposited on Highway 11 on April 1. This photo shows the amount of material, including tephra and Pele's Hair, that had accumulated by 3:30 p.m. HST. A Hawaii County Civil Defense Agency message at 12:49 p.m.

Kīlauea summit eruption episode 16 lava fountain and its lava flow on April 1, 2025. The lava fountain was reaching heights of more than 650 ft (200 m) at times and feeding a lava flow that as of noon on April 1 reached about 2,300 ft (700 m) from its vent. The lava fountain was also depositing a tephra blanket to the northwest that was reaching Highway 11.

Kīlauea summit lava fountain from the west end of Halemaʻumaʻu and the tephra blanket it has produced through its 16 episodes. In some places, the tephra blanket reaches more than 5 ft (1.5 m) thick. Most of the tephra from episode 16 lava fountain on April 1, 2025, was blowing to the northwest, with some clasts reaching Highway 11. USGS photo by D. Downs.

USGS Hawaiian Volcano Observatory geologist captured this aerial view during a monitoring helicopter overflight of episode 16 at around noon on April 1, 2025.  The lava fountain feeds a lava flow from the western end of Halemaʻumaʻu.

Lava fountaining during episode 15 of the summit eruption at Kīlauea volcano. USGS webcam image.

View of north vent from the northwest, nearly 12 hours after the end of episode 15 of the eruption at Kīlauea's summit. Tephra covers the slopes of north vent, and the area to the north, giving the appearance of a surface covered in brown sand.

Photo of a tree partially buried and damaged by the tephra deposit produced by the high fountaining on March 26, 2025, during episode 15 of Kīlauea's summit eruption in Halema‘uma‘u. Prior to episode 15, this was a healthy tree growing in a gully, about 130 meters (about 140 yards) west of the rim of Halema‘uma‘u.

This compilation shows thermal maps made shortly after three different lava fountaining episodes at the summit of Kīlauea. Each fountaining episode produced short-lived lava flows in the western portion of the crater floor, near the vent, which were inactive and solidified by the time of the thermal maps.

USGS Hawaiian Volcano Observatory geologists observed the fountain activity and monitored changing fountain heights during episode 15 of the Halema‘uma‘u eruption. This photo was taken at 1:00 p.m. HST on March 26 during the high fountain stage of the episode. Photo direction is looking south. Fountain heights reached up to about 750 feet (230 meters) at this time.

Lava fountain activity during episode 15 of the Halema‘uma‘u eruption at the summit of Kīlauea. Fountain heights reached up to about 1,000 feet (305 meters) during episode 15. Vigorous lava fountaining feeds lava flows on the floor of Halemaʻumaʻu crater.  USGS photo by C. Gansecki. 

A USGS Hawaiian Volcano Observatory geologist takes measurements of the fountain heights during episode 15 of the Kīlauea summit eruption in Halema‘uma‘u. This photo, looking south, was taken at around 10:41 a.m. HST on March 26, during the beginning stages of the high fountains. Fountains from the south vent reached over the top of the crater wall at this time.

During the cyclic low fountain to drainback phase of episode 15, both the north and south vents were active. This low-level activity began March 25 around 9:30 a.m. HST and continued for just over 24 hours before the fountaining phase began. USGS photo by H Winslow.

Lava fountain activity during episode 15 of the Halema‘uma‘u eruption at the summit of Kīlauea. Fountain heights reached up to about 1,000 feet (305 meters) during episode 15. USGS photo by C. Gansecki. 

On March 26, 2025, during the early stages of episode 15 of the Halema‘uma‘u eruption, the north vent exhibited cyclic low fountaining and drainback. Here, the lava lake is at its peak overflowing into lava flows at 8:15 a.m. HST, before draining once again. USGS photo by H Winslow.