Warning! Mount Semeru Erupts Again Early This Morning (Thursday, December 18, 2025)

Mount Semeru in East Java erupted again on Thursday (18/12/2025) at 04:53 AM WIB. In the last week, Mount Semeru has erupted 14 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 500 meters above the peak (4,176 meters above sea level).

The ash column was observed to be white to gray with thick intensity towards the southeast and south. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 135 seconds.

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

According to MAGMA Indonesia's volcanic activity report, Mount Semeru's activity level is at Level III (Siaga/Alert). Seismicity observations on December 18, 2025, from 18:00-23:59 WIB, showed 30 eruption earthquakes with amplitudes of 10-23 millimeters and durations of 88-158 seconds.

Then, 1 rockfall earthquake with an amplitude of 2 mm and a duration of 41 seconds, and 4 exhalation earthquakes with amplitudes of 5-7 millimeters and durations of 37-51 seconds occurred.

PVMBG advises against any activity in the southeast sector along Besuk Kobokan, as far as 13 kilometers from the peak (eruption center). Beyond this distance, the public is advised not to engage in activities within 500 meters from the riverbank (river border) 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 7,375 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,038 occurrences.

(Read: Trends in Volcanic Eruptions in Recent Years)