Warning! Mount Semeru Erupts Again This Afternoon (Thursday, December 4, 2025)

Mount Semeru in East Java erupted again on Thursday (4/12/2025) at 3:37 PM WIB. In the last week, Mount Semeru has erupted 58 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 observed reached None meters above the peak or None meters above sea level.

The eruption's visuals were not observed. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 121 seconds.

(Read: Volcanic Eruption Trends in Recent Years)

According to MAGMA Indonesia's volcanic activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 4, 2025, from 06:00-12:00 WIB, showed 32 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and durations of 50-204 seconds.

Then, 1 rockfall earthquake with an amplitude of 4 mm and a duration of 29 seconds, and 3 emission earthquakes with amplitudes of 4-8 millimeters and durations of 43-47 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, the public is advised not to conduct 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 7,194 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,937 events.

(Read: Countries with the Most Active Volcanoes in the World, Indonesia Ranks First)