The Weekly Volcanic Activity Report: December 17-23, 2025
New activity/unrest was reported for 4 volcanoes from December 17 to 23, 2025. During the same period, ongoing activity was reported for 19 volcanoes.
Kīlauea enters eruptive episode 39 exactly one year into ongoing summit eruption, with lava fountains rising over 420 m (1 400 feet)
Kīlauea entered eruptive episode 39 at 20:10 HST on December 23, 2025 (06:10 UTC on December 24) as lava fountains rose from twin vents on the floor of Halemaʻumaʻu crater. Within about 95 minutes, fountain heights increased from 10 m (30 feet) to more than 420 m (1 400 feet), with lava flows covering 10–20% of the crater floor by 21:14 HST and a plume reaching 6 000 m (20 000 feet).
Sand miner trapped by large lahar on Mount Semeru, Indonesia
A large lahar triggered by heavy rains on Mount Semeru trapped a man in the Regoyo River in East Java, on Sunday, December 21, 2025.
The Weekly Volcanic Activity Report: December 10-16, 2025
New activity/unrest was reported for 5 volcanoes from December 10 to 16, 2025. During the same period, ongoing activity was reported for 17 volcanoes.
The Weekly Volcanic Activity Report: December 3-9, 2025
New activity/unrest was reported for 7 volcanoes from December 3 to 9, 2025. During the same period, ongoing activity was reported for 21 volcanoes.
Glacial outburst flood in Skaftá River confirmed to originate from Vestari-Skaftár caldera, Iceland
A glacial outburst flood in Iceland’s Skaftá River, first detected on December 8, 2025, has been confirmed to originate from the Vestari-Skaftár caldera beneath Vatnajökull ice cap. Flow at the Sveinstind station has decreased to just over 120 m³/s, down from 200 m³/s earlier in the week. Conductivity remains high and hydrogen sulfide continues to be detected along the river, but no impacts on major roads have been reported.
USGS V3 camera destroyed by lava fountain during Kīlauea’s Episode 38, Hawaiʻi
A powerful lava fountain from Kīlauea’s Halemaʻumaʻu crater, Hawaiʻi, destroyed the USGS Hawaiian Volcano Observatory’s V3 streaming camera at around 10:00 HST (20:00 UTC) on December 6, 2025. The camera was recording live when an inclined fountain from the south vent buried it in hot pumice and tephra during Episode 38 of the ongoing summit eruption.
Episode 38 at Kīlauea produces extremely rare triple-fountain event and destroys USGS camera, Hawaiʻi
Kīlauea’s Halemaʻumaʻu crater, Hawaiʻi, began erupting at 08:45 HST (18:45 UTC) on December 6, 2025, when fountains emerged from the north vent, marking the start of Episode 38 of the ongoing summit eruption. Within minutes, a south vent opened, and by 09:15 HST a rare triple-vent lava fountain was active, producing jets up to 370 m (1 200 ft) high and a 6 km (20 000 feet) plume above the summit. The eruption lasted 12.1 hours, covered more than half of Halemaʻumaʻu crater with new lava, destroyed the USGS V3 streaming camera, and ended abruptly at 20:52 HST on the same day (06:52 UTC on December 7).
Ambae volcano erupting after months of quiet, Vanuatu
Low-level eruptive activity resumed at Ambae volcano (Manaro Voui) in Vanuatu, with intermittent ash emissions observed since December 1, 2025. Satellite imagery from Himawari-9 confirmed continuous low-level ash and gas plumes reaching up to 1.8 km (6 000 feet) above sea level, drifting northwest. The Wellington Volcanic Ash Advisory Centre (VAAC) issued its latest advisory on December 4, describing the eruption as continuous but confined within the volcano’s summit area.
The Weekly Volcanic Activity Report: November 26-December 2, 2025
New activity/unrest was reported for 9 volcanoes from November 26 to December 2, 2025. During the same period, ongoing activity was reported for 20 volcanoes.
