Mount Semeru Erupts Again This Afternoon, Ash Plume Around 1,000 Meters High

Mount Semeru in East Java erupted again on Friday (December 5, 2025) at 4:13 PM WIB. In the last week, Mount Semeru has erupted 71 times.

Reporting eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the ash plume observed reached 1,000 meters above the peak or 4,676 meters above sea level.

The ash plume was observed to be white to gray with thick intensity towards the east. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 108 seconds.

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According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 5, 2025, from 06:00-12:00 WIB, showed 31 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and durations of 77-160 seconds.

Furthermore, there were 3 puffing earthquakes with amplitudes of 5-8 millimeters and durations of 30-67 seconds, and 1 harmonic earthquake with an amplitude of 20 millimeters and a duration of 149 seconds.

PVMBG advises against any activities in the southeast sector along Besuk Kobokan, 13 kilometers from the peak (eruption center). Beyond that distance, people should not engage in activities within 500 meters from the riverbanks (river borders) 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 7,214 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,950 incidents.

(Read: Number of Victims Suffering-Displaced Due to Natural Disasters in Indonesia 2015-2024)