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

Mount Semeru in East Java erupted again on Thursday (9/11/2025) at 00:32 WIB. In the last week, Mount Semeru has erupted 19 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 600 meters above the peak (4,276 meters above sea level).

The observed ash column was grey with thick intensity towards the west. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 172 seconds.

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According to MAGMA Indonesia''s 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 exhalation tremors with amplitudes of 3-8 millimeters and durations of 37-66 seconds.

PVMBG advises against any activities 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 along Besuk Kobokan, as there is potential for expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,040 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,421 times.

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