Volcanic activity at Mount Semeru, located on the border of Lumajang and Malang Regencies, East Java, showed a significant increase on Friday (3/7/2026). The highest mountain on Java Island, standing at 3,676 meters above sea level (masl), was recorded to have erupted seven times in just four hours.
An officer at the Mount Semeru Observation Post, Liswanto, explained that this series of eruptions began at 06:06 WIB with an eruption column reaching a height of 700 meters. The intensity of the eruptions continued to fluctuate, with ash column heights ranging from 400 to 1,300 meters above the summit.
As of now, Mount Semeru remains at Alert Level III (Siaga). Volcanic monitoring authorities emphasized that the public should not carry out any activities in the southeastern sector along Besuk Kobokan, up to 13 kilometers from the eruption center. This prohibition was enacted due to the potential threat of pyroclastic flows, lava avalanches, and lahar flows that endanger residents' safety.
In addition to the restricted zone in Besuk Kobokan, the public is also forbidden from engaging in activities within a five-kilometer radius of the main crater to avoid the risk of incandescent rock ejection. Residents are urged to remain vigilant against potential hazards from rivers originating at the peak of Mount Semeru, particularly along the Besuk Bang, Besuk Kembar, and Besuk Sat river basins, to mitigate disaster risks amidst high volcanic activity.
