Mount Semeru Erupts on Saturday Afternoon, Status on Alert

Mount Semeru in East Java erupted again on Saturday (20/12/2025) at 16:50 WIB. In the last week, Mount Semeru has erupted 53 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 was observed to be around None meters above the peak or None meters above sea level.

The visual eruption was not observed. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 104 seconds.

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According to MAGMA Indonesia's volcano activity report, the activity level of Mount Semeru is at Level III (Alert). Seismic observations on December 20, 2025, from 06:00-12:00 WIB, showed 29 eruption earthquakes with amplitudes of 10-22 millimeters and earthquake durations of 58-154 seconds.

Additionally, there were 5 avalanche earthquakes with amplitudes of 2-4 mm and durations of 39-53 seconds, and 2 exhalation earthquakes with amplitudes of 3-8 millimeters and durations of 36-77 seconds.

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

Throughout 2025, MAGMA Indonesia has recorded 7,431 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,077 events.

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