Warning! Mount Semeru Erupts Again Tonight (Friday, September 12, 2025)

Mount Semeru in East Java erupted again on Friday (9/12/2025) at 00:29 AM Western Indonesian Time. In the last week, Mount Semeru has erupted 29 times.

Based on 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).

Visual eruption was not observed. The eruption of Mount Semeru was still ongoing when this report was made.

(Read: Volcanic Eruption Trends in Recent Years)

According to MAGMA Indonesia''s volcanic activity report, Mount Semeru''s activity level is at Level II (Alert). Seismicity observations on September 12, 2025, from 00:00-23:59 Western Indonesian Time showed 60 eruption tremors/earthquakes with amplitudes of 10-22 millimeters and durations of 64-225 seconds.

Additionally, 4 rockfall earthquakes with amplitudes of 3-10 mm and durations of 58-109 seconds, and 3 emission earthquakes with amplitudes of 3-8 millimeters and durations of 32-60 seconds occurred.

PVMBG advises against any activities in the southeast sector along Besuk Kobokan, as far as 8 kilometers from the peak (eruption center). Beyond this distance, the public should not engage in activities within 500 meters from the riverbanks (river boundaries) 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 6,061 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most, with 2,431 occurrences.

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