INDOPOSCO.ID – Mount Semeru, located on the border of Lumajang and Malang in East Java, was observed emitting white smoke rising between 500 meters and 1 kilometer from its summit on Monday morning (Nov. 24, 2025).
“Visually, the volcano was clearly visible until obscured by level 0–II mist. The main crater emitted white smoke with moderate intensity, rising approximately 500–1,000 meters above the peak,” said Mukdas Sofian, officer at the Semeru Observation Post, in a written report received in Lumajang on Monday (Nov. 24, 2025).
The weather around the 3,676-meter-high volcano was mostly cloudy to overcast, with light easterly winds and temperatures ranging between 21–22 degrees Celsius.
During the six-hour observation period from 00:00–06:00 WIB, 44 eruption-related tremors were recorded, with amplitudes ranging from 10–22 mm and durations of 64–147 seconds.
“In addition, one puffing tremor with an amplitude of 8 mm and duration of 52 seconds was recorded, along with three distant tectonic tremors ranging 3–30 mm, S-P 39 seconds, and durations between 51–284 seconds,” he added.
Semeru is currently at Level IV (AWAS – Danger). The Center for Volcanology and Geological Disaster Mitigation (PVMBG) has advised residents not to engage in any activities in the southeastern sector along Besuk Kobokan up to 20 kilometers from the summit.
Outside this zone, people are urged to keep at least 500 meters from riverbanks due to potential hot clouds and lahars.
“Residents are also prohibited from entering an eight-kilometer radius from the crater due to the risk of incandescent rock ejection,” Mukdas said.
Heightened vigilance is recommended for possible pyroclastic flows, lava streams, and lahars along rivers originating from Semeru’s summit, particularly Besuk Kobokan, Besuk Bang, Besuk Kembar, Besuk Sat, and smaller tributaries, according to Antara.
Observation post records indicate that Semeru erupted again on Monday, Nov. 24, 2025, at 03:04 WIB. While the eruption was not visually observed, it was clearly recorded by seismographs, with a maximum amplitude of 22 mm and a duration of 142 seconds. (aro)
