Mount Semeru erupts 11 times with ash columns reaching 1,200 metres

Lumajang, East Java — Mount Semeru, located on the border between Lumajang and Malang regencies in East Java, experienced 11 eruptions with ash columns reaching up to 1,200 metres above its peak on Sunday morning.

The first eruption occurred at 00:20 local time, with no visual observation reported. At the time of reporting, the eruption was still ongoing, and whilst several eruptions did not produce visible ash columns, the highest eruption occurred at 05:47 local time.

The ash column was observed to be white to grey in colour with medium intensity directed southward, and eruptions were continuing at the time of reporting. The 11th eruption occurred at 06:32 local time, with an observed ash column height of 1,000 metres above the peak (4,676 metres above sea level) and white to grey ash with thick intensity directed eastward and southeastward.

The eruption was recorded on seismographs with a maximum amplitude of 22 millimetres and a duration of 133 seconds.

Mount Semeru is currently at Alert Level III (Standby), with the Centre for Volcanology and Geological Disaster Mitigation providing several recommendations. The public is prohibited from conducting any activities in the southeastern sector along Besuk Kobokan, extending 13 kilometres from the peak (the eruption centre).

Beyond this distance, the public is prohibited from conducting activities within 500 metres of riverbanks along Besuk Kobokan, as there is a potential risk of pyroclastic flows and lahars extending up to 17 kilometres from the peak.

The public is also prohibited from conducting activities within a five-kilometre radius of the crater or peak of Mount Semeru, as there is danger from flying volcanic rocks.

Residents are urged to remain vigilant regarding the potential for pyroclastic flows, lava avalanches, and lahars along all river valleys and tributaries originating from Mount Semeru’s peak, particularly along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as lahars in smaller rivers that are tributaries of Besuk Kobokan.