Photo & Video Chronology – August 25, 2025 – Sampling episode 31 at the summit of Kīlauea

By Hawaiian Volcano Observatory August 25, 2025

On August 25, 2025, USGS Hawaiian Volcano Observatory field crews sampled lava and tephra from episode 31 during a morning monitoring overflight of Kīlauea summit. Episode 31 of the ongoing Halemaʻumaʻu eruption began at 2:04 p.m. HST on August 22 and ended at 2:52 a.m. HST on August 23 after nearly 13 hours of continuous fountaining.

Color photograph of volcanic crater with degassing plume rising above it

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A helicopter can be seen in the upper left portion of the photo, with USGS Hawaiian Volcano Observatory geologists onboard conducting a photogrammetric survey of Halema‘uma‘u crater floor following the episode 31 lava fountaining on August 22-23, 2025. The passive outgassing plume originates from the vent complex that has been active in the current eruption. USGS photo by M. Patrick.

Color photograph of shield volcano with caldera wall in the foreground

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A helicopter carries USGS Hawaiian Volcano Observatory geologists over Wahinekapu (Steaming Bluff) as it flies over Kīlauea's summit caldera to conduct a photo survey following the episode 31 lava fountaining. Mauna Loa can be seen in the distance. USGS photo by M. Patrick.

Color photograph of degassing plume above caldera

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Clear weather provided good conditions for a helicopter overflight of Kīlauea summit the morning of August 25, 2025. The overflight allowed USGS Hawaiian Volcano Observatory geologists to conduct a photogrammetric survey of the crater floor following the episode 31 lava fountaining late last week, as well as to collect lava samples. The passive outgassing plume rises from the vent complex that has been active in the western end of the crater. USGS photo by M. Patrick.

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During a Kīlauea monitoring overflight on August 25, 2025, USGS Hawaiian Volcano Observatory field crews documented the proximal channel that fed lava flows from the north vent to the floor of Halema‘uma‘u during episode 31. This image, looking to the north (the north vent is just out of sight to the bottom of the photo), shows the proximal Pāhoehoe channel flanked by lighter brown tephra deposits to the left and right. USGS photo by K. Lynn.

Color photograph of volcanic vent degassing

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During a Kīlauea summit monitoring overflight on August 25, 2025, USGS Hawaiian Volcano Observatory field crews documented the geometry of the north vent that fountained predominantly during episode 31. The conduit is at a high angle into the southwest wall of the north vent. USGS photo by K. Lynn.

Color photograph of scientist collecting geologic samples near degassing volcanic vent

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On August 25, 2025, USGS Hawaiian Volcano Observatory field crews sampled lava and tephra from episode 31 during a morning monitoring overflight of Kīlauea summit. Samples from the episode will be later analyzed in the lab to track changes in the chemistry of erupted material and help scientists understand the processes driving the 2024-2025 episodic eruption. USGS photo by P. Dotray.

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Lava fountained for nearly 13 hours on August 22-23 during episode 31 of the ongoing eruption at the summit of Kīlauea volcano on the Island of Hawaiʻi. USGS Hawaiian Volcano Observatory scientists documented the eruptive episode, which included a lava fountain that extended 1,000 ft (300 meters) from the north vent, feeding a lava channel and depositing tephra on the floor of Halemaʻumaʻu crater. The south vent and additional intermediate vents also erupted during this episode. With the permission of Hawaiʻi Volcanoes National Park, USGS scientists conducted a monitoring overflight of the eruption site on August 25, during which they visited the floor of Halemaʻumaʻu crater to collect a sample of material erupted during episode 31. Geochemical analysis of the sample will help scientists to understand the processes driving this episodic eruption that has been occurring since December 23, 2024. USGS video.