Mount Semeru Erupts Again Tonight (Thursday, December 18, 2025)

Mount Semeru in East Java erupted again on Thursday (18/12/2025) at 7:10 PM WIB. In the last week, Mount Semeru has erupted 23 times.

Citing 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 117 seconds.

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According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level III (Alert). Seismic observations on December 18, 2025, from 12:00-18:00 WIB showed 37 eruption quakes with amplitudes of 10-22 millimeters and durations of 63-134 seconds.

Additionally, there was 1 rockfall earthquake with an amplitude of 10 mm and a duration of 75 seconds, and 1 exhalation earthquake with an amplitude of 8 millimeters and a duration of 30 seconds.

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, people should not engage in activities within 500 meters from the riverbanks (river borders) along Besuk Kobokan, as there is a potential for hot cloud expansion and lava flows up to 17 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 7,389 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,047 recorded.

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