Warning! Mount Semeru Erupts Again This Morning (Tuesday, October 7, 2025)

Mount Semeru in East Java erupted again on Tuesday (7/10/2025) at 05:21 AM Western Indonesia Time (WIB). In the last week, Mount Semeru has erupted 10 times.

Citing eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column height reached 300 meters above the peak or 3,976 meters above sea level.

The ash column was observed to be white to grey with moderate intensity towards the southwest. Mount Semeru's eruption was still ongoing when this report was made.

(Read: Not Jakarta, These Are the Areas with the Worst Air Quality in Indonesia (Wednesday, June 7, 2023))

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismic observations on October 7, 2025, from 00:00-23:59 WIB showed 83 eruption tremors with amplitudes of 12-23 millimeters and a duration of 50-167 seconds.

Followed by 5 emission tremors with amplitudes of 3-8 millimeters and durations of 39-105 seconds, and 1 local tectonic tremor with an amplitude of 20 millimeters s-p 5 seconds and a duration of 29 seconds.

PVMBG advises against any activities in the southeast sector along Besuk Kobokan, up to 8 kilometers from the peak (eruption center). Beyond that distance, the public is advised not to engage in activities within 500 meters of the riverbanks (river borders) along Besuk Kobokan, as there is a potential for hot cloud expansion and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,563 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions with 2,571 occurrences.

(Read: Air Quality in Major Indonesian Cities is Poor, Far from WHO Standards)