Indonesia’s Mount Semeru erupts 10 times in 13 hours, triggering warnings over deadly flows

Indonesia’s Mount Semeru erupts 10 times in 13 hours, triggering warnings over deadly flows



Mount Semeru in East Java, Indonesia erupted at least 10 times on October 13, 2026, sending volcanic ash 900 metres above its summit. — File picture from X/@saddamovic


Summary

• Indonesia's Mount Semeru in East Java experienced a series of eruptions on Tuesday, propelling volcanic ash up to 900 meters above its summit.
• The Volcanology and Geological Hazard Mitigation Centre (PVMBG) reported that eruptions occurred primarily between 12:09 am and 1:11 pm, with ash drifting towards the southwest and west.
• Mount Semeru remains at Level III on Indonesia's volcanic alert system, prompting advisories to avoid areas within 13 kilometers of the summit, particularly near the Besuk Kobokan River, due to potential pyroclastic and volcanic mudflows.
• The public is also cautioned against activities within a five-kilometer radius of the crater due to the risk of ejected rocks.

First Published: Tuesday, 13 Oct 2026 4:01 PM MYT


JAKARTA, Oct 13 — Indonesia’s Mount Semeru in East Java erupted at least 10 times on Tuesday, sending volcanic ash up to 900 metres above its summit.

According to the Volcanology and Geological Hazard Mitigation Centre (PVMBG), the eruptions occurred between 12.09am and 1.11pm local time, with ash clouds drifting southwest and west.


Based on a report on its official website, the highest ash columns, reaching 900 metres above the summit or 4,576 metres above sea level, were recorded during eruptions at 5.20am and 6.47am.


With Mount Semeru remaining at Level III, the second-highest level on Indonesia’s four-tier volcanic alert system, PVMBG advised the public to avoid all activities within 13 kilometres of the summit along the Besuk Kobokan River in the volcano’s southeastern sector due to the risk of pyroclastic flows and volcanic mudflows.


“People must also avoid all activities within a five-kilometre radius of Mount Semeru’s crater or summit due to the danger of ejected incandescent rocks,” it said.



The report noted that the volcano, located on the border of Lumajang and Malang regencies in East Java, also erupted five times between 12.09am and 5.13am, producing ash columns ranging from 300 to 800 metres, followed by two eruptions at 8.10am and 10.37am that sent ash 800 metres above the summit.

It said the latest reported eruption at 1.11pm produced a 600-metre ash column drifting southwest, with seismic instruments recording a maximum amplitude of 15 millimetres and a duration of 88 seconds. — Bernama