Mount Semeru Erupts Again Tonight (Friday, December 5, 2025)

Mount Semeru in East Java erupted again on Friday (December 5, 2025) at 00:43 WIB. In the last week, Mount Semeru has erupted 62 times.

Citing 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 1,000 meters above the peak (4,676 meters above sea level).

The ash column was observed to be white to grey with moderate intensity towards the north. The eruption of Mount Semeru was still ongoing when this report was made.

(Read: Volcanic Eruption Trends in Recent Years)

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level III (Alert). Seismicity observations on December 5, 2025, from 18:00-23:59 WIB, showed 27 eruption tremors/earthquakes with amplitudes of 10-22 millimeters and durations of 92-176 seconds.

Furthermore, 7 avalanche tremors with amplitudes of 2-13 mm and durations of 41-234 seconds, and 9 emission tremors with amplitudes of 2-7 millimeters and durations of 44-95 seconds occurred.

PVMBG urges people not to carry out any activities in the southeast sector along Besuk Kobokan, as far as 13 kilometers from the peak (eruption center). Beyond this distance, the public should not engage in activities within 500 meters of the riverbank (river border) along Besuk Kobokan, as there is a potential for expansion of hot clouds and lava flows up to 17 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 7,202 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,941 occurrences.

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