Warning! Mount Semeru Erupts Again This Morning (Wednesday, December 17, 2025)

Mount Semeru in East Java erupted again on Wednesday (December 17, 2025) at 05:48 AM WIB. In the last week, Mount Semeru has erupted 11 times.

Based on 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 500 meters above the peak or 4,176 meters above sea level.

The ash column was observed to be white to gray with thick intensity towards the northeast. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 115 seconds.

(Read: Trends in Volcanic Eruptions in Recent Years)

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 17, 2025, from 18:00-23:59 WIB, showed 41 eruption earthquakes with amplitudes of 15-23 millimeters and durations of 89-158 seconds.

Additionally, there were 3 avalanche earthquakes with amplitudes of 2-12 mm and durations of 71-93 seconds, and 4 emission earthquakes with amplitudes of 2-4 millimeters and durations of 33-64 seconds.

PVMBG advises against any activity in the southeast sector along Besuk Kobokan, up to 13 kilometers from the peak (eruption center). Beyond that distance, people should not engage in activities within 500 meters from the riverbanks (river boundaries) 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 7,367 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,035 recorded events.

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