Mount Semeru Erupts Five Times, Spewing Ash up to 700 Metres
Mount Semeru, located on the border of Lumajang and Malang regencies in East Java, erupted five times on Monday morning, with eruption column heights ranging from 300 to 700 metres above the peak.
The first eruption occurred at 00:18 Western Indonesia Time, with an observed column height of approximately 500 metres above the summit. The ash column was observed to be white to grey with moderate intensity, moving northwards.
“Then it erupted again at 00:31 Western Indonesia Time with an observed column height of around 700 metres above the peak,” said Mount Semeru Observation Post officer Liswanto in a written report received in Lumajang.
He explained that the third eruption took place at 01:46 Western Indonesia Time, with an observed column height of about 600 metres above the summit. The ash column was white to grey with moderate intensity, heading north.
The highest mountain on Java island erupted again at 05:50 Western Indonesia Time, with an observed column height of around 300 metres above the peak and ash drifting southwest.
At 07:56 Western Indonesia Time, Mount Semeru erupted once more, with an observed ash column reaching 700 metres above the summit. The ash was white to grey with thick intensity, moving southeast. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimetres and a duration of 120 seconds.
Liswanto explained that the volcano’s activity status remains at Level III (Siaga). He recommended that the public refrain from any activities in the southeastern sector along Besuk Kobokan, as far as 13 kilometres from the summit, which is the eruption centre.
Beyond that distance, residents are advised not to carry out activities within 500 metres of the riverbank along Besuk Kobokan, due to the potential for expansion of hot clouds and lava flows up to 17 kilometres from the peak.
“The public is prohibited from conducting activities within a five-kilometre radius of the crater or peak of Mount Semeru, due to the danger of incandescent rock projectiles,” he said.
He urged the public to remain vigilant against the potential for hot clouds, lava avalanches, and lahars along river channels and valleys originating from the peak of Mount Semeru, particularly along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lahars in small streams that are tributaries of Besuk Kobokan.