Mount Semeru Erupts Again This Afternoon (Thursday, September 25, 2025)

Mount Semeru in East Java erupted again on Thursday (25/9/2025) at 17:02 WIB. In the last week, Mount Semeru has erupted 24 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 reach None meters above the peak (None meters above sea level).

The visual eruption was not observed. Mount Semeru's eruption was still ongoing when this report was made.

(Read: Floods and Extreme Weather, The Most Frequent Natural Disasters in Indonesia until Early August 2023)

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismic observations on September 25, 2025, at 00.00-23.59 WIB showed 74 eruption tremors with amplitudes of 10-22 millimeters and durations of 56-176 seconds.

Subsequently, 5 avalanche tremors with amplitudes of 2-3 mm and durations of 34-102 seconds, and 10 exhalation tremors with amplitudes of 3-8 millimeters and durations of 19-98 seconds occurred.

PVMBG advises against any activity in the southeastern sector along Besuk Kobokan, as far as 8 kilometers from the peak (eruption center). Beyond that distance, people should not engage in activities within 500 meters from the riverbank (river boundary) along Besuk Kobokan, as there is a potential for expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,330 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most, with 2,490 eruptions.

(Read: 2 Thousand Natural Disasters in Indonesia in 2024, Floods Dominate)