Volcanic activity at Mount Semeru, located on the border of Lumajang and Malang Regencies, East Java, reportedly surged again on Friday (10/7/2026). Throughout the morning, Java's highest volcano recorded six eruptions with varying ash column heights.
Liswanto, an officer at the Mount Semeru Observation Post, revealed that the first eruption occurred at 06:29 WIB with an ash column reaching 1.1 kilometers high. The intensity of the eruption increased during the second blast at 07:39 WIB, where an ash column was observed reaching 1.3 kilometers above the summit, drifting toward the north and northeast sectors.
Heading into the afternoon, the eruption frequency remained steady, with ash column heights ranging between 500 meters and 1.2 kilometers. The ash material accompanying the eruptions was mostly white to gray, with thick intensity at several observation points.
Responding to this increased activity, the Center for Volcanology and Geological Hazard Mitigation (PVMBG) established an exclusion zone within a five-kilometer radius of the main crater. This measure was taken to mitigate the risk of incandescent rock projections that could occur at any time.
In addition, the public has been urged to remain vigilant against potential pyroclastic flows and cold lava streams, particularly residents living near river basins originating at Semeru's summit. Areas of special concern include the flows of Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat.
Local authorities emphasized that residents should refrain from any activity within a 500-meter radius of the riverbank along Besuk Kobokan, given that the area is highly vulnerable to the expansion of pyroclastic flows and lava streams up to a distance of 17 kilometers from the peak.
