Inp.polri.go.id - Lumajang.  Mount Semeru emitted a white volcanic plume rising 1,000 meters above its summit, according to the Geological Agency under the Ministry of Energy and Mineral Resources early Saturday (22/11/2025). 

The eruption occurred while the volcano remains under Alert Level IV status, the country’s highest threat status.

“The visual activity recorded a continuous plume with moderate to strong intensity reaching 1,000 meters at 00.10 am local time,” the Geological Agency said in a written statement released, as quoted by antaranews.com. 

Seismic monitoring detected 157 eruption quakes, along with rockfall and tremor events.

Hours earlier, residents in nearby Lumajang Regency panicked when a secondary eruption occurred along the Besuk Kobokan river channel, triggered by cold lava flooding over hot volcanic deposits. Authorities shut down access to the Gladak Perak Bridge due to ash clouds and low visibility as response teams ordered people away from high-risk zones.

Current restrictions ban activity within 20 km of the southeast sector and 8 km from the crater, due to risks of pyroclastic flows, lava, and volcanic mudflow floods.

(mg/inp/pr/rs)