Mount Semeru Erupts with 1km Ash Column Saturday Evening, Alert Level III

Mount Semeru, located on the border of Lumajang and Malang regencies in East Java, has again shown increased volcanic activity. On Saturday (30 May) evening, the highest peak in Java erupted with a column height reaching 1 kilometre above the summit. Mukdas Sofian, a monitoring post officer at Mount Semeru, confirmed the eruption occurred at 16:57 WIB. “The observed eruption column height was approximately 1,000 metres above the summit or 4,676 metres above sea level,” Mukdas stated in his written report. Visual observations showed a white to grey volcanic ash column with thick intensity moving westward. Seismographic data recorded a maximum amplitude of 22 mm and a duration of 171 seconds for the eruption event. Mount Semeru is currently at Level III (Alert) status. Authorities have issued strict recommendations for the public and tourists to avoid risks from volcanic material falls and pyroclastic flows. Mukdas also warned residents to be cautious of potential cold lahars, especially if rain occurs at the summit. These lahar flows could travel through rivers originating from Semeru’s peak, such as Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, including smaller tributaries nearby.