Mount Semeru Erupts on Sunday Afternoon, Activity Level at Alert

Mount Semeru in East Java erupted again on Sunday (9/28/2025) at 17:07 WIB. In the last week, Mount Semeru has erupted 55 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 observed reached None meters above the peak (None meters above sea level).

Visual eruption was not observed. The eruption was recorded on a seismograph with a maximum amplitude of 20 millimeters and a duration of 107 seconds.

(Read: Floods, the Most Prevalent Natural Disaster in Indonesia as of September 2025)

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismic observations on September 28, 2025, from 00:00-23:59 WIB showed 70 eruption earthquakes with amplitudes of 11-22 millimeters and durations of 45-186 seconds.

Subsequently, there were 17 emission earthquakes with amplitudes of 3-8 millimeters and durations of 29-70 seconds, and 1 harmonic earthquake with an amplitude of 14 millimeters and a duration of 54 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, the public should not engage in activities within 500 meters from the riverbanks 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 6,416 volcano eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,521 occurrences.

(Read: Global Economic Losses Due to Flooding Decreased in 2023)