Volcanic ash from Semeru volcano observed at 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 03:10 UTC on October 15, 2025. The advisory was issued by the Darwin VAAC at 03:30 UTC.

The ash cloud was detected between the surface and flight level 140 (approximately 4 300 m or 14 100 feet). The plume was moving west at 9 km/h (5 mph). Satellite imagery from Himawari-8 confirmed a weak ash signal extending to the west-northwest. The current Aviation Color Code is Orange. Intermittent discrete eruptions were expected to continue according to the advisory. No other specific hazard information was provided.

According to a recent summary by the Global Volcanism Program, daily eruptive events at Semeru were recorded during late September 2025. Daily white-and-gray or gray ash plumes rose 400–900 m above the summit and drifted in various directions. The public was advised to maintain a safe distance from the volcano due to continued hazards.

Semeru is a large stratovolcano located in East Java, Indonesia. Known hazards include ashfall, pyroclastic flows, and lahars that can threaten nearby communities, particularly in regions downwind and along river drainages such as the Kobokan. The nearest significant population center is the city of Lumajang, which lies approximately 35 km (22 miles) to the southeast. Persistent activity at Semeru presents ongoing threats to local settlements and agriculture.