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 15:10 UTC on October 25, 2025. The advisory was issued by the Darwin VAAC at 15:30 UTC.

Ash was reported at altitudes from the surface up to 4 300 m (14 100 feet) based on ground observations and model guidance. Satellite imagery did not show the ash cloud due to meteorological cloud cover, but intermittent discrete eruptions were reported from ground sources. The ash cloud was reported to be moving west at 18 km/h (11 mph). The current Aviation Color Code is Orange.

According to the Global Volcanism Program, Semeru continued to be active during the recent reporting period, with daily eruptive events and ash plumes rising 400–900 m above the summit and drifting in several directions. The Alert Level remained at 2 (on a scale of 1-4). Authorities advised the public to avoid areas within 3 km of the summit and areas up to 8 km southeast due to hazards from lahars, avalanches, and pyroclastic flows.

Semeru is a large stratovolcano located in East Java, Indonesia. Known hazards include ashfall, pyroclastic flows, lava flows, and lahars. Populated areas near Semeru include the towns of Lumajang and Malang, both of which are at risk during significant eruptive episodes. The volcano poses a threat to communities within a radius of several kilometers due to its frequent activity and potential for large explosive eruptions.