Ash plume from Semeru volcano reaches 4 300 m (14 100 feet) a.s.l., Indonesia

Volcanic ash from Semeru in Indonesia was observed at 4 300 m (14 100 feet) above sea level at 03:40 UTC on October 12, 2025. The advisory was issued by the Darwin VAAC at 04:00 UTC.

The ash cloud was reported at surface to flight level 140, corresponding to an altitude of approximately 4 300 m (14 100 feet). The ash was moving toward the southwest at an estimated 37 km/h (23 mph). Due to meteorological cloud cover, volcanic ash was not identifiable on recent satellite imagery; observations were based on ground reports and model guidance. The current Aviation Color Code is Orange.

According to the Smithsonian / USGS Weekly Volcanic Activity Report for September 24-30, 2025, Semeru continued to produce daily eruptive events, with white-and-gray or gray ash plumes rising 400-900 m above the summit and drifting in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and public advisories remained in place for exclusion zones around the summit and specific drainages.

Semeru is a stratovolcano located in East Java, Indonesia and is the highest volcano on the island. It is known for frequent explosive eruptions and pyroclastic flows. Ashfall, lava flows, and lahars are common hazards, posing risks to nearby towns such as Lumajang and Malang, which are located within 40 km (25 miles) of the volcano.