Mount Semeru Erupts Again This Morning, Volcanic Ash Column 300 Meters Above Peak

Mount Semeru in East Java erupted again on Tuesday (9/23/2025) at 05:25 AM Western Indonesia Time. 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 observed ash column height reached 300 meters above the peak (3,976 meters above sea level).

The ash column was observed to be white to grey with thick intensity towards the west and northwest. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 130 seconds.

(Read: Majority of Villages in IKN Area at Risk of Floods)

According to MAGMA Indonesia''s volcano activity report, Mount Semeru''s activity level is at Level II (Alert). Seismicity observations on September 23, 2025, from 00:00-23:59 WIB showed 65 eruption/explosion earthquakes with amplitudes of 11-22 millimeters and durations of 61-226 seconds.

Subsequently, there were 4 rockfall earthquakes with amplitudes of 2-3 mm and durations of 53-78 seconds, and 15 emission earthquakes with amplitudes of 3-8 millimeters and durations of 39-80 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 conduct activities within 500 meters from the riverbanks (river borders) along Besuk Kobokan due to the potential for being affected by the expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,285 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,476 occurrences.

(Read: Bekasi Among 10 Highest Flood-Risk Areas in West Java)