Warning! Mount Semeru Erupts Again This Afternoon (Monday, December 22, 2025)

Mount Semeru in East Java erupted again on Monday (December 22, 2025) at 11:05 AM WIB. In the last week, Mount Semeru has erupted 9 times.

Citing eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the height of the observed ash column reached None meters above the peak (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 148 seconds.

(Read: Jakarta's Air Quality This Morning is the Third Worst in the World (Tuesday, June 6, 2023))

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 22, 2025, from 00:00-06:00 WIB showed 42 eruption tremors with amplitudes of 12-22 millimeters and durations of 62-147 seconds.

Furthermore, there were 18 avalanche tremors with amplitudes of 4-7 mm and durations of 35-105 seconds, and 1 harmonic tremor with an amplitude of 12 millimeters and a duration of 100 seconds.

PVMBG advises against any activity 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 river bank (river border) 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 7,474 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 3,107 times.

(Read: Jakarta and Medan are Among the World's Worst Polluted Cities, Here's the Trend in Their Air Quality)