Mount Semeru Eruption: 1,000-Metre Plume, Alert Level III

Mount Semeru, situated on the border of Lumajang and Malang districts in East Java, erupted on Friday morning with a plume reaching 1,000 metres above the summit. The eruption was first observed at 06:44 WIB by Liswanto of the Mount Semeru Observation Post. The ash plume was seen white to gray with moderate intensity, directed toward the northeast. ‘The eruption column reached about 1,000 metres above the summit or around 4,676 metres above sea level (masl),’ Liswanto stated in a written report. Not long after, a second eruption occurred at 07:55 WIB. In this second eruption, the summit could not be clearly observed due to thick fog, and eruptive activity was reported to be ongoing at the time of this report. Currently, Mount Semeru remains at Level III (Siaga) for volcanic activity. In response, the Center for Volcanology and Geological Disaster Mitigation (PVMBG) issued stringent recommendations to ensure safety for residents around the mountain’s slopes. Residents are strictly prohibited from engaging in any activity in the southeastern sector, particularly along Besuk Kobokan, up to 13 kilometres from the summit or eruption center. Outside this distance, residents are also asked not to operate within a 500-metre radius from the river edge along Besuk Kobokan, due to the potential expansion of hot ash clouds and lava flows that could reach up to 17 kilometres from the summit. Authorities continue to urge the public to remain calm but vigilant, and to always follow the directions of local disaster mitigation officers, given the high potential for secondary hazards from rain-induced lahars in the Besuk Kobokan river basins.