Mount Sinabung Activity Increases, Deep Volcanic Earthquakes Detected

Mount Sinabung (2,451 metres above sea level) in Karo Regency, North Sumatra, has shown an increase in activity.

The Mount Sinabung Monitoring Post stated that the volcano’s seismic activity is dominated by tectonic and volcanic earthquakes, although not in significant numbers.

The head of the Mount Sinabung Monitoring Post, Armen Putra, said that seismic monitoring over the weekend, on 1 August 2026, showed an increase in deep volcanic earthquakes.

“In addition, blowing earthquakes, low-frequency earthquakes and hybrid earthquakes, which were previously rarely recorded, have also been detected,” said Armen Putra on Monday (3/8).

According to Armen, crater smoke emissions were observed as thin to moderate white plumes, rising to heights of between 50 and 600 metres above the lava dome.

“This increase in seismic activity needs to be anticipated, given the potential hazards of Mount Sinabung in the form of phreatic or magmatic eruptions,” he explained.

Armen added that the potential collapse of the lava dome could also occur if pressure within the magmatic system increases significantly.

“The current activity level of Mount Sinabung is Level II (Alert/Waspada) as of 17 May 2023,” he outlined.

Since March 2024, the Centre for Volcanology and Geological Hazard Mitigation (PVMBG) has recommended that residents, tourists and climbers refrain from any activity within a 2-kilometre radius of the summit of Mount Sinabung, as well as a sectoral radius of 3.5 kilometres for the south-east sector of the volcano.

Beyond the direct threats of incandescent rock ejections and ashfall, the public is also reminded of the potential secondary hazard of lava flows, particularly during the rainy season. Lava flows could travel through rivers in the south-west sector that originate at the summit of Mount Sinabung.