Warning! Mount Semeru Erupts Again Tonight (Monday, December 29, 2025)

Mount Semeru in East Java erupted again on Monday (29/12/2025) at 18:30 WIB. In the last week, Mount Semeru has erupted 69 times.

According to eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the height of the ash column observed was approximately 700 meters above the peak (4,376 meters above sea level).

The ash column was observed to be white to gray with thick intensity towards the northeast. The eruption was recorded on a seismograph with a maximum amplitude of 21 millimeters and a duration of 105 seconds.

(Read: Number of Houses Damaged by Floods and Landslides in Sumatra (December 17, 2025))

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level III (Siaga/Alert). Seismicity observations on December 29, 2025, from 12:00-18:00 WIB, showed 31 eruption earthquakes with amplitudes of 15-22 millimeters and earthquake durations of 61-144 seconds.

Additionally, there was 1 exhalation earthquake with an amplitude of 5 millimeters and a duration of 17 seconds, and 2 distant tectonic earthquakes with amplitudes of 15-22 millimeters, s-p of 17-18 seconds, and durations of 58-60 seconds.

PVMBG advises against any activity in the southeast sector along Besuk Kobokan, up to 13 kilometers from the peak (eruption center). Beyond that distance, people should not engage in activities within 500 meters of the riverbanks along Besuk Kobokan due to the potential for hot cloud expansion and lava flows up to 17 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 7,548 volcano eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,142 events.

(Read: Distribution of Fatalities Due to Floods and Landslides in Aceh (December 9, 2025))