Mount Semeru Erupts, Ash Column Reaches 1,000 Metres Above Summit

Mount Semeru, located on the border of Lumajang and Malang regencies in East Java, erupted on Thursday evening, with the eruption height reaching 1,000 metres above the summit. “An eruption of Mount Semeru occurred at 17:15 WIB, with the observed eruption column height approximately 1,000 metres above the peak or 4,676 metres above sea level,” said Mount Semeru Observation Post officer Mukdas Sofian in a written report received in Lumajang. According to him, the ash column was observed to be white to grey with thick intensity heading southwest. The eruption was recorded on a seismograph with a maximum amplitude of 22 mm and a duration of 165 seconds. Based on officer records, Mount Semeru, the highest mountain on Java Island, has erupted 12 times since 05:00 WIB until 17:30 WIB, with eruption heights ranging from 500 metres to 1,200 metres above the summit. He explained that the volcanic activity of Mount Semeru is currently at Status Level III (Alert), with a recommendation that the public not conduct any activities in the southeastern sector along Besuk Kobokan as far as 13 kilometres from the summit (eruption centre). Beyond that distance, he continued, the public should not conduct activities within 500 metres of the riverbank (river border) along Besuk Kobokan, as there is potential for expansion of pyroclastic flows and lava flows up to a distance of 17 kilometres from the summit. “The public is prohibited from conducting activities within a five-kilometre radius of the crater/peak of Mount Semeru because it is prone to the danger of ejected incandescent rocks,” he said. He urged the public to be aware of the potential for pyroclastic flows, lava avalanches, and lahars along the river/valley flows originating at the summit of Mount Semeru. “Especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lahars in small rivers that are tributaries of Besuk Kobokan,” said Mukdas.