The Weekly Volcanic Activity Report: September 3–9, 2025
New activity/unrest was reported for 5 volcanoes from September 3 to 9, 2025. During the same period, ongoing activity was reported for 21 volcanoes.
Rainfall keeps lahar hazard active at Fuego volcano after initial flows, Guatemala
Weak to moderate lahars descended from Fuego volcano, Guatemala, at 19:17 LT on September 10, 2025, moving through Barranca Ceniza and into the Zarco and Mazate rivers, tributaries of the Achíguate River. The National Institute of Seismology, Volcanology, Meteorology and Hydrology (INSIVUMEH) reported that conditions remain favorable for additional lahars on the southwestern flanks.
Fumarole temperatures and gas fluxes rise at Vulcano volcano, Italy
Carbon dioxide fluxes at Vulcano volcano, Aeolian Islands, Italy, sharply increased in August 2025, reaching more than 40 000 g/m²/day on August 18, before stabilizing around 30 000 g/m²/day.
Lewotobi Laki-laki volcano alert raised to highest level, Indonesia
Indonesia’s Geological Agency raised the alert status of Mount Lewotobi Laki-laki in East Flores to Level IV (Awas) at 10:00 WITA on September 6, 2025, due to increased seismicity, continuous tremor, and deformation indicating shallow magma ascent.
The Weekly Volcanic Activity Report: August 27–September 2, 2025
New activity/unrest was reported for 6 volcanoes from August 27 to September 2, 2025. During the same period, ongoing activity was reported for 23 volcanoes.
Magma accumulation under Svartsengi nears eruption threshold, Iceland
Around 6 to 7 million m3 (212 to 247 million ft3) of magma have accumulated beneath Svartsengi, Iceland since the eruption on July 16, 2025. At the current rate of accumulation, the estimated threshold of 12 million m3 (424 million ft3) could be reached in the latter half of September, increasing the likelihood of a new eruption.
Lava fountains reach 150 m (500 feet) as Kīlauea eruption episode 32 starts
Episode 32 of the Halemaʻumaʻu eruption at Kīlauea volcano, Hawaii, began at 16:35 UTC (06:35 HST) on September 2, 2025, producing lava fountains up to 150 m (500 feet) high. The eruption remains confined to the summit crater within Hawai‘i Volcanoes National Park.
Earthquake swarm with 90 events detected at Teide volcano, Tenerife, Canary Islands
A new seismic swarm with 90 tremors was recorded beneath Mount Teide on the island of Tenerife, Canary Islands, Spain, on August 30, 2025.
Explosive eruption at Santa Maria volcano, Guatemala
An explosive eruption occurred at Santa María volcano, Guatemala, at around 06:40 UTC on August 29, 2025, producing an ash plume that reached 4.2 km (14 000 feet) above sea level — approximately 500 m (1 640 feet) above the summit.
Shinmoedake eruption sends ash plume to 7 km above sea level, Japan
Shinmoedake volcano, part of the Kirishimayama complex in Japan, erupted on August 27, 2025, producing an ash plume rising to 7 km (23 000 feet) a.s.l., which drifted south at 19 km/h (12 mph).
