Mount Semeru has once again shown a significant increase in volcanic activity on Thursday (6/25/2026). The volcano, which stands at 3,676 meters above sea level (masl), was recorded experiencing five eruptions since early morning, with the strongest eruption reaching a height of 1.2 kilometers above the peak.
Mount Semeru Observation Post officer, Liswanto, confirmed that the largest eruption occurred at 09:24 WIB, spewing a column of white-to-gray ash of moderate intensity toward the south. This phenomenon was recorded as the peak of a series of eruptions that began at 05:44 WIB with a column height reaching 700 meters.
To date, the volcanic activity status of Mount Semeru remains at Level III (Alert). Authorities strongly advise the public against conducting any activities in the southeastern sector along Besuk Kobokan, within a 13-kilometer radius from the eruption center. This prohibition is enforced given the high potential threat of pyroclastic flows and lahar flows.
Additionally, the public is asked to stay outside a five-kilometer radius from the main crater to avoid the risk of hazardous incandescent rock falls. Residents active around river basins originating from the volcano's peak, such as Besuk Bang, Besuk Kembar, and Besuk Sat, are urged to remain vigilant against secondary threats of lava avalanches and cold lahar flows, especially during periods of heavy rainfall.
