Mount Semeru Erupts Early Sunday, Status is Alert

Mount Semeru in East Java erupted again on Sunday (28/12/2025) at 04:59 AM WIB. In the last week, Mount Semeru has erupted 38 times.

Based on 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 500 meters above the peak or 4,176 meters above sea level.

The ash column was observed to be gray with moderate to thick intensity towards the northeast. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 129 seconds.

(Read: Volcanic Eruption Trends in Recent Years)

According to MAGMA Indonesia's volcanic activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 28, 2025, from 18:00-23:59 WIB showed 41 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and earthquake durations of 75-143 seconds.

Subsequently, 4 rockfall earthquakes with an amplitude of 2 mm and durations of 35-45 seconds, and 3 harmonic earthquakes with amplitudes of 2-10 millimeters and durations of 187-2909 seconds occurred.

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

Throughout 2025, MAGMA Indonesia has recorded 7,530 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,136 events.

(Read: Indonesia Has the Most Active Volcanoes in the World)