Mount Semeru Erupts Again Early This Morning, Ash Column 700 Meters Above Peak

Mount Semeru in East Java erupted again on Monday (22/9/2025) at 02.43 AM WIB. In the last week, Mount Semeru has erupted 2 times.

Citing eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column reached 700 meters above the peak (4,376 meters above sea level).

The ash column was observed to be white to grey with thick intensity towards the southwest. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 164 seconds.

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

According to MAGMA Indonesia''s volcanic activity report, Mount Semeru''s activity level is at Level II (Alert). Seismicity observations on September 22, 2025, from 00.00-23.59 WIB showed 70 eruption earthquakes with amplitudes of 10-22 millimeters and durations of 50-195 seconds.

Furthermore, there were 3 rockfall earthquakes with amplitudes of 4-6 mm and durations of 57-59 seconds, and 14 exhalation earthquakes with amplitudes of 3-8 millimeters and durations of 34-77 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 of the riverbank (river boundary) along Besuk Kobokan due to the potential for hot clouds and lava flows extending up to 13 kilometers from the peak.

During 2025, MAGMA Indonesia recorded 6,238 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,468 events.

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