Mount Semeru Erupts Again Tonight, Ash Plume Reaches Approximately 1,000 Meters

Mount Semeru in East Java erupted again on Friday (December 19, 2025) at 8:02 PM WIB. In the last week, Mount Semeru has erupted 39 times.

Based on 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 gray with thick intensity moving eastward. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 141 seconds.

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According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level III (Siaga/Alert). Seismicity observations on December 19, 2025, from 12:00 PM to 6:00 PM WIB showed 4 eruption tremors with amplitudes of 10-22 millimeters and durations of 55-99 seconds.

Subsequently, there were 3 exhalation tremors with amplitudes of 4-7 millimeters and durations of 37-53 seconds, and 1 distant tectonic earthquake with an amplitude of 11 millimeters s-p 17 seconds and a duration of 52 seconds.

PVMBG urges 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 conduct activities within 500 meters from the riverbanks (river borders) along Besuk Kobokan due to the potential for expansion of hot clouds and lava flows up to 17 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 7,412 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,063 occurrences.

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