Warning! Mount Semeru Erupts Again Tonight (Sunday, December 28, 2025)

Mount Semeru in East Java erupted again on Sunday (28/12/2025) at 23:34 WIB. In the last week, Mount Semeru has erupted 43 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 500 meters above the peak or 4,176 meters above sea level.

The ash column was observed to be white to grey with thick intensity towards the north. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 122 seconds.

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

According to MAGMA Indonesia's volcano activity report, the activity level of Mount Semeru is at Level III (Siaga/Alert). Seismicity observations on December 28, 2025, at 12:00-18:00 WIB showed 37 eruptive/explosion earthquakes with amplitudes of 10-22 millimeters and durations of 60-133 seconds.

Furthermore, there were 5 avalanche earthquakes with amplitudes of 2-4 mm and durations of 41-45 seconds, and 8 puff/exhalation earthquakes with amplitudes of 2-6 millimeters and durations of 35-56 seconds.

PVMBG advises against any activity in the southeast sector along Besuk Kobokan, as far as 13 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, as there is a potential for expansion of pyroclastic flows and lava flows up to 17 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 7,541 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,141 occurrences.

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