Warning! Mount Semeru Erupts Again This Afternoon (Thursday, September 11, 2025)

Mount Semeru in East Java erupted again on Thursday (9/11/2025) at 15:59 WIB. In the last week, Mount Semeru has erupted 21 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 approximately None meters above the peak or None meters above sea level.

No visual eruption was observed. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 184 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 11, 2025, from 00:00-23:59 WIB showed 46 eruption tremors with amplitudes of 10-22 millimeters and durations of 54-183 seconds.

Additionally, there were 6 rockfall tremors with amplitudes of 3-10 mm and durations of 45-172 seconds, and 10 emission tremors with amplitudes of 3-8 millimeters and durations of 37-66 seconds.

PVMBG advises 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 engage in activities within 500 meters from the riverbanks (river boundaries) along Besuk Kobokan due to the potential for expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,047 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,423 occurrences.

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