Mount Semeru Erupts Again Tonight (Monday, October 20, 2025)

Mount Semeru in East Java erupted again on Monday (10/20/2025) at 21:19 WIB. In the last week, Mount Semeru has erupted 7 times.

Reporting eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column height 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 21 millimeters and a duration of 135 seconds.

(Read: There were 1,300 Natural Disasters in Indonesia until September 2024, Here are the Details)

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismicity observations on October 20, 2025, at 00:00-23:59 WIB showed 81 eruption earthquakes with amplitudes of 10-23 millimeters and durations of 57-203 seconds.

Subsequently, there were 71 rockfall earthquakes with amplitudes of 2-9 mm and durations of 31-123 seconds, and 18 exhalation earthquakes with amplitudes of 3-9 millimeters and durations of 40-75 seconds.

PVMBG advises against any activities in the southeast sector along Besuk Kobokan, as far as 8 kilometers from the peak (eruption center). Beyond that distance, the public should not carry out activities within 500 meters from the riverbank (river boundary) along Besuk Kobokan due to the potential for expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,724 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most, with 2,647 eruptions.

(Read: There were 749 Natural Disaster Incidents in Indonesia until the End of March 2023, Floods Most Numerous)