Warning! Mount Semeru Erupts Again Tonight (Thursday, September 4, 2025)

Mount Semeru in East Java erupted again on Thursday (4/9/2025) at 09:09 PM Western Indonesia Time. In the last week, Mount Semeru has erupted 18 times.

Reporting 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 None meters above the peak or None meters above sea level.

Visual observation of the eruption was not observed. The eruption of Mount Semeru was still ongoing when this report was made.

(Read: Hundreds of Natural Disasters Until Early April 2024, Floods Most Frequent)

According to MAGMA Indonesia''s volcanic activity report, Mount Semeru''s activity level is at Level II (Alert). Seismicity observations on September 4, 2025, from 00:00-23:59 WIB, showed 45 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and durations of 50-179 seconds.

Furthermore, there were 2 rockfall earthquakes with amplitudes of 6-10 mm and durations of 63-80 seconds, and 2 exhalation earthquakes with an amplitude of 8 millimeters and durations of 53-55 seconds.

PVMBG advises against any activities in the southeast sector along Besuk Kobokan, as far as 8 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 hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 5,961 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,386 occurrences.

(Read: Recipients of Apartment Units 2022, Most are Victims of Natural Disasters)