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

Mount Semeru in East Java erupted again on Thursday (4/12/2025) at 17:26 WIB. In the last week, Mount Semeru has erupted 59 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 21 millimeters and a duration of 128 seconds.

(Read: Indonesia Has the Most Active Volcanoes in the World)

According to the MAGMA Indonesia volcano 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 earthquakes with amplitudes of 10-22 millimeters and durations of 50-204 seconds.

Subsequently, 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 occurred.

PVMBG urges against any activities in the southeast sector along Besuk Kobokan, as far as 13 kilometers from the peak (eruption center). Beyond this distance, people should not engage in activities within 500 meters from the riverbanks (river border) along Besuk Kobokan, as there is a potential for expansion of hot clouds and lava flows up to 17 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 7,196 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,938 times.

(Read: Volcanic Eruption Trends in Recent Years)