Warning! Mount Semeru Erupts Again Tonight (Wednesday, October 1, 2025)

Mount Semeru in East Java erupted again on Wednesday (1/10/2025) at 8:55 PM WIB. In the last week, Mount Semeru has erupted 20 times.

Based on 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 or 4,376 meters above sea level.

The observed ash column was gray with thick intensity towards the southwest. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 193 seconds.

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

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismicity observations on October 1, 2025, from 00:00-23:59 WIB, showed 63 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and durations of 71-180 seconds.

Additionally, there were 18 shallow volcanic earthquakes with amplitudes of 2-8 millimeters and durations of 31-89 seconds, and 1 felt earthquake, scale III MMI, with an amplitude of 30 millimeters, S-P arrival time unobserved, and a duration of 579 seconds.

PVMBG advises against any activity in the southeast sector along Besuk Kobokan, within 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 hot clouds and lava flows extending up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,490 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,542 events.

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