Mount Semeru Erupts Again Tonight, Ash Column Height Around 900 Meters

Mount Semeru in East Java erupted again on Wednesday (September 24, 2025) at 21:40 WIB (Western Indonesian Time). In the last week, Mount Semeru has erupted 16 times.

Based on eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the ash column height was observed to be around 900 meters above the peak (4,576 meters above sea level).

The ash column was observed to be gray with thick intensity towards the northwest. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 126 seconds.

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According to the MAGMA Indonesia volcano activity report, Mount Semeru''s activity level is at Level II (Alert). Seismicity observations on September 24, 2025, from 00:00-23:59 WIB, showed 71 eruption tremors with an amplitude of 10-22 millimeters and a duration of 56-189 seconds.

Furthermore, there were 6 rockfall tremors with an amplitude of 2-3 mm and a duration of 39-102 seconds, and 13 exhalation tremors with an amplitude of 3-8 millimeters and a duration of 44-71 seconds.

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 engage in activities within 500 meters from the riverbanks (river borders) along Besuk Kobokan, as there is a potential for expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,310 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most, with 2,482 eruptions.

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