A volcanic eruption on the island of Sumatra has thrown a colossal ash cloud into the sky above western Indonesia.

A plume of volcanic debris measuring more than four miles (7km) in length sprang from the mouth of Mount Sinabung on the northern part of the island on Monday afternoon, sparking widespread travel disruption amid an aviation ‘red notice’ and airport closures. The alert prohibits airlines from flying over parts of the country with significant amounts of ash in the atmosphere. No casualties have yet been reported.

The Australian Bureau of Meteorology’s Volcanic Ash Advisory Centre (VACC) has issued maps showing the ash cloud moving out in three separate directions from Sinabung — to the north, northwest and south-southeast. Sinabung is around 47 miles south-west of Kualanamu International Airport in Medan.

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Speaking to Reuters, a spokesman for Indonesia’s National Disaster Mitigation Agency said a four-mile exclusion zone had been set up around the crater, and that the public are being asked to watch out for weather warnings.

Mount Sinabung’s most destructive eruption occurred in 2014, killing more than a dozen people and displacing thousands of others. The volcano had been thought to be dormant, having last erupted around four hundred years ago.

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Mount Agung, on the island of Bali to the south, has also been active for a number of months. Indonesia sits on the Ring of Fire, a 40,000km horseshoe-shaped area covering the circumference of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur.

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