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

Volcanic ash from Semeru volcano in Indonesia was observed at 4 300 m (14 100 feet) above sea level at 09:10 UTC on October 30, 2025. The advisory was issued by the Darwin VAAC at 09:30 UTC.

The ash cloud height was identified as reaching flight level 140 (approximately 4 300 m or 14 100 feet). The current Aviation Color Code is Orange. Although the volcanic ash could not be seen in the latest satellite imagery due to meteorological cloud cover, ground reports indicated intermittent, discrete eruptions remain ongoing. Ash movement was reported toward the west at 9 km/h (6 mph), with forecast locations for similar ash cloud heights at 6, 12, and 18 hours after the observation.

According to the Smithsonian/USGS Weekly Volcanic Activity Report for September 24–30, 2025, Semeru maintained daily eruptive activity, generating ash plumes rising 400–900 m (1 300–3 000 feet) above the summit and drifting in multiple directions. The public was advised to keep at least 3 km (1.9 miles) from the summit in all directions and 8 km (5 miles) to the southeast due to the risk of pyroclastic flows and lahars.

Semeru is a stratovolcano located in East Java, Indonesia. It is known for frequent explosive eruptions, ashfall, pyroclastic flows, and lava flows. The nearby village of Sumberwuluh and other settlements within 20 km (12 miles) may be at risk from ashfall or more hazardous phenomena during larger eruptive events.