Six Volcanoes Erupt Consecutively in Late August, PVMBG: No Evidence of Mutual Triggering

Six volcanoes in Indonesia erupted simultaneously on 31 August 2026. The Centre for Volcanology and Geological Hazard Mitigation (PVMBG) of the Geological Agency, under the Ministry of Energy and Mineral Resources, has confirmed that this phenomenon did not trigger one another.

According to news agency Antara on Thursday (3/9/2026), the six volcanoes that erupted concurrently include Mount Ibu in North Maluku, Mount Semeru in East Java, Mount Lewotobi Laki-laki and Mount Ili Lewotolok in East Nusa Tenggara, Mount Anak Krakatau in the Sunda Strait, and Mount Sinabung in North Sumatra.

The Head of PVMBG, Rita Susilani, emphasised Indonesia’s position within the Pacific Ring of Fire, which contains 127 active volcanoes. She stated that this positioning allows for eruptions to occur on the same day without any systemic connection.

“To put it simply, each volcano has its own ‘kitchen’; they are independent, and the processes leading to eruption differ from one volcano to another. We have found no evidence of a single geological process triggering all these eruptions simultaneously on 31 August,” said Rita.

Rita also clarified public perceptions regarding earthquakes often being linked to volcanic eruptions. According to her, tectonic earthquakes do not automatically trigger eruptions unless proven by surges in internal volcanic monitoring data.

The dynamics of these simultaneous eruptions have increased the activity level of Mount Sinabung in North Sumatra from Level II (Alert) to Level III (Siaga) since 31 August 2026 at 12:00 WIB, after it ejected a volcanic ash column 3,500 metres above the peak.

Meanwhile, Mount Anak Krakatau in the Sunda Strait remains at Level III (Siaga), a status in effect since 2 July 2026. Its ash column eruption on 31 August 2026 reached a height of 200 metres.

Responding to the concerns of coastal residents in Banten and Lampung regarding the potential for a tsunami caused by Anak Krakatau’s explosion, PVMBG has urged the public not to panic, as such eruptions do not necessarily result in a tsunami.

PVMBG has requested that residents adhere to danger recommendations, specifically evacuating the danger zone within a 3-kilometre radius of Mount Sinabung’s peak (and a 6-kilometre radius in the south-eastern sector) and remaining vigilant against the threat of rain-induced lahars along riverbeds originating from the peak.