Mount Semeru Erupts Again Tonight (Wednesday, September 17, 2025)

Mount Semeru in East Java erupted again on Wednesday (September 17, 2025) at 23:28 WIB. In the last week, Mount Semeru has erupted 10 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 observed 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 22 millimeters and a duration of 167 seconds.

(Read: Countries with the Most Active Volcanoes in the World, Indonesia Ranks First)

According to the MAGMA Indonesia volcano activity report, Mount Semeru''s activity level is at Level II (Alert). Seismic observations on September 17, 2025, from 00:00-23:59 WIB showed 54 eruption/emission earthquakes with amplitudes of 10-22 millimeters and durations of 50-225 seconds.

Then, 9 rockfall earthquakes with amplitudes of 2-8 mm and durations of 48-114 seconds, and 8 emission earthquakes with amplitudes of 4-8 millimeters and durations of 35-71 seconds occurred.

PVMBG urges against any activity in the southeast sector along Besuk Kobokan, as far as 8 kilometers from the peak (eruption center). Beyond that distance, people should not conduct activities within 500 meters from the riverbanks (river borders) along Besuk Kobokan due to the potential for expansion of hot clouds and lahar flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,137 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,457 occurrences.

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