Geological Agency warns of potential larger Sinabung eruption

 The Geological Agency of the Ministry of Energy and Mineral Resources (ESDM) predicted a larger eruption following the initial eruption of Mount Sinabung in Karo District, North Sumatra, on Monday.

"This is an initial eruption and does not rule out the possibility of a larger eruption," Head of the Geological Agency Lana Saria informed on Monday.

She said Mount Sinabung’s volcanic activity would remain under close monitoring, with its status reassessed regularly and whenever significant changes are detected to guide preparedness efforts.

The agency previously detected Mount Sinabung erupting on Monday with an eruption column reaching approximately 3,500 meters above the summit, or approximately 5,960 meters above sea level.

A thick, black ash column was observed leaning toward the east and southeast. The eruption was recorded on a seismogram with a maximum amplitude of 120 millimeters.

Increased volcanic activity had been detected before the eruption.

The Geological Agency recorded 85 volcanic earthquakes, one gust earthquake, and one harmonic tremor before the eruption at 10:17 a.m. local time.

Based on the results of visual and instrumental monitoring, the agency also raised Mount Sinabung's activity level from Level II to Level III (Alert) effective August 31, 2026, at 12:30 p.m. The volcano had previously been at Level II since May 17, 2023.

At Level III, residents and visitors must refrain from activities in relocated villages and within a three-kilometer radius of the summit of Mount Sinabung and a six-kilometer sectoral radius to the south-southeast.

Residents living near rivers originating from Mount Sinabung are also urged to remain alert to potential lava flows.

Monitoring from August 1-30, 2026, showed Mount Sinabung emitting white and gray smoke from its main crater, with a thin to thick intensity, at a height of approximately 50-1,000 meters from the summit.

Furthermore, vegetation on the eastern slopes was observed to be yellowing and drying.

The Geological Agency urged the public to remain calm, increase vigilance, and follow the directions of the North Sumatra Provincial Disaster Mitigation Agency (BPBD) and the Karo District Disaster Mitigation Agency (BPBD).

The local government was also urged to maintain coordination with the Sinabung Volcano Observation Post in Ndokum Siroga Village. Updates on volcanic activity are available through the Geological Agency’s official PVMBG app and channels.