Indonesia’s Semeru Volcano Erupts Again, Triggering Pyroclastic Flows and Highest Alert Level

Indonesia’s Semeru volcano, the tallest peak on Java and one of the country’s most dangerous, has roared back to life, unleashing towering ash clouds and fast-moving pyroclastic flows as authorities raised its alert status to the maximum level.

The volcanology agency said Semeru blasted ash up to 5.6km (3.48 miles) into the sky on Wednesday and warned residents to remain at least 2.5km (1.55 miles) away from the crater. The eruption began around 4pm local time, according to monitoring officer Mukdas Sofian.

“Pyroclastic flows are still occurring, with the runout distance reaching seven kilometres from the summit, and the eruption was ongoing at the time this report was prepared,” Sofian said.

Semeru, or Mahameru, sits in one of Java’s most densely populated regions. Standing at 3,676 metres (12,060 feet), it forms part of the Pacific Ring of Fire — a vast arc of tectonic volatility where major quakes and eruptions are routine.

The volcano has a long, violent history. In 2021, an explosive eruption killed 62 people and buried entire villages under thick volcanic debris. With nearly 130 active volcanoes across the country, Indonesia monitors Semeru closely due to its frequent activity and the risk it poses to nearby communities, transport routes and aviation.

Authorities have warned that additional eruptions remain possible as volcanic tremors continue.