Mount Semeru Erupts Again This Morning (Monday, December 22, 2025)

Mount Semeru in East Java erupted again on Monday (22/12/2025) at 05:29 AM Western Indonesian Time. In the last week, Mount Semeru has erupted 7 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 700 meters above the peak (4,376 meters above sea level).

The ash column was observed to be white to gray with moderate intensity towards the north. Mount Semeru's eruption was still ongoing when this report was made.

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According to MAGMA Indonesia's volcanic activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 22, 2025, at 18:00-23:59 WIB showed 46 eruption tremors with amplitudes of 11-22 millimeters and durations of 67-168 seconds.

Subsequently, there were 17 avalanche tremors with amplitudes of 2-7 mm and durations of 31-85 seconds, and 8 exhalation tremors with amplitudes of 3-8 millimeters and durations of 28-69 seconds.

PVMBG urges 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 due to the potential for expansion of hot clouds and lava flows up to 17 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 7,471 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,105 events.

(Read: Floods Dominate Natural Disasters in Indonesia End of February 2024)