Warning! Mount Semeru Erupts Again Tonight (Friday, December 5, 2025)

Mount Semeru in East Java erupted again on Friday (5/12/2025) at 10:37 PM WIB. In the last week, Mount Semeru has erupted 81 times.

Based on eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column reached 22 meters above the peak or 3,698 meters above sea level.

The observed ash column was white to gray with moderate intensity towards the south. The eruption of Mount Semeru was still ongoing when this report was made.

(Read: Jakarta's Air Quality is Poor, Losing to Other ASEAN Capitals)

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 5, 2025, from 12:00-18:00 WIB, showed 22 eruption earthquakes with amplitudes of 10-22 millimeters and earthquake durations of 58-170 seconds.

Then, 6 rockfall earthquakes with amplitudes of 2-3 mm and earthquake durations of 34-67 seconds, and 13 emission earthquakes with amplitudes of 2-9 millimeters and earthquake durations of 71-91 seconds occurred.

PVMBG advises against any activities in the southeast sector along Besuk Kobokan, as far as 13 kilometers from the peak (eruption center). Beyond that distance, the public is advised not to engage in activities within 500 meters from the riverbanks (river boundaries) 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 7,225 volcano eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,960 times.

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