Mount Semeru, located in East Java, showed volcanic activity once again on Monday (6/7/2026). The eruption occurred at exactly 08:13 WIB, spewing a column of volcanic ash up to 1,000 meters above the peak, or approximately 4,676 meters above sea level.
According to a report from the Volcano Observation Post officer, Sigit Rian Alfian, the observed ash column was thick, ranging from white to gray, and moving towards the northeast and east. This eruptive activity was recorded on a seismograph with a maximum amplitude of 22 millimeters, lasting for 134 seconds.
As a precautionary measure, authorities have issued a strict warning to the public to refrain from any activities in the southeastern sector along Besuk Kobokan, within a 13-kilometer radius from the eruption center. This restriction is enforced due to the potential expansion of pyroclastic flows and lahar flows that could reach up to 17 kilometers from the peak.
Furthermore, residents are prohibited from conducting activities within a 5-kilometer radius of the crater peak due to the risk of dangerous incandescent rock projection. The public is urged to remain highly vigilant against the threats of pyroclastic flows, lava avalanches, and cold lahar floods, especially for those living or active near the banks of rivers originating directly from the peak of Mount Semeru, such as Besuk Bang, Besuk Kembar, Besuk Sat, and Besuk Kobokan.
