Warning! Mount Semeru Erupts Again This Morning (Tuesday, October 21, 2025)

Mount Semeru in East Java erupted again on Tuesday (10/21/2025) at 10:28 AM Western Indonesian Time. In the last week, Mount Semeru has erupted 15 times.

Citing eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the height of the ash column was observed to be around None meters above the peak or None meters above sea level.

The visual of the eruption was not observed. The eruption was recorded on a seismograph with a maximum amplitude of 21 millimeters and a duration of 99 seconds.

(Read: BNPB Records 52 Natural Disasters in Mid-August 2023, Most of Which Were Forest and Land Fires)

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismic observations on October 21, 2025, from 00:00-23:59 WIB showed 55 eruption earthquakes with amplitudes of 10-23 millimeters and durations of 64-154 seconds.

Furthermore, there were 40 rockfall earthquakes with amplitudes of 2-10 mm and durations of 30-110 seconds, and 15 degassing earthquakes with amplitudes of 2-7 millimeters and durations of 43-97 seconds.

PVMBG urges against any activity in the southeast sector along Besuk Kobokan, as far as 8 kilometers from the peak (eruption center). Beyond this distance, the public is advised not to engage in activities within 500 meters from the riverbanks along Besuk Kobokan due to the potential for being affected by the expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,734 volcano eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,655 times.

(Read: There Are Still 381 High-Risk Forest and Land Fire Hotspots in Indonesia in Early 2023)