Warning! Mount Semeru Erupts Again Tonight (Tuesday, September 2, 2025)

Mount Semeru in East Java erupted again on Tuesday (September 2, 2025) at 00:42 WIB. In the last week, Mount Semeru has erupted 3 times.

According to 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 200 meters above the peak (3,876 meters above sea level).

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

(Read: There were 1,300 Natural Disasters in Indonesia until September 2024, Here are the Details)

According to MAGMA Indonesia''s volcanic activity report, Mount Semeru''s activity level is at Level II (Alert). Seismic observations on September 2, 2025, from 00:00-23:59 WIB showed 45 eruption tremors with amplitudes of 10-22 millimeters and a duration of 54-185 seconds.

Subsequently, there were 3 rockfall tremors with amplitudes of 2-8 mm and a duration of 54-71 seconds, and 9 exhalation tremors with amplitudes of 3-8 millimeters and a duration of 43-115 seconds.

PVMBG advises against any activity in the southeast sector along Besuk Kobokan, as far as 8 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, as there is a potential for hot cloud expansion and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 5,924 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,371 times.

(Read: These are the Damages Caused by Natural Disasters from January-March 2023)