Mount Semeru Erupts Again This Morning (Tuesday, August 12, 2025)

Mount Semeru in East Java erupted again on Tuesday (August 12, 2025) at 05.17 WIB. In the last week, Mount Semeru has erupted 10 times.

Reporting eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the height of the ash column was observed to be around None meters above the peak (None meters above sea level).

The visual eruption was not observed. The eruption was recorded on a seismograph with a maximum amplitude of 21 millimeters and a duration of 148 seconds.

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

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismic observations on August 12, 2025, at 00.00-23.59 WIB showed 47 eruption earthquakes with amplitudes of 10-22 millimeters and earthquake durations of 50-248 seconds.

Subsequently, 14 times of exhalation earthquakes with amplitudes of 4-8 millimeters and earthquake durations of 39-105 seconds, and 4 times of harmonic earthquakes with amplitudes of 3-8 millimeters and earthquake durations of 104-234 seconds occurred.

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 from the riverbanks (river borders) along Besuk Kobokan due to the potential for being hit by expanding hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 5,568 volcano eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,227 times.

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