Scientists are anticipating an eruption at Mount Agung in Bali, Indonesia for the first time in more than 50 years.

Disruptions under the volcano’s surface have put the island on high alert, and hundreds of thousands of people have been told to evacuate. Residents are being shepherded to temporary shelters, and signs reading, "You're entering active volcanic hazard zone" have been erected.

But what does this mean for the island, and the rest of the world? Here’s everything you need to know.

Where is Mount Agung?

Mount Agung, the tallest mountain in Bali, is located on the island’s western edge. It is located 612 miles (984km) from Indonesia's capital of Jakarta, and 11 miles (18km) from Bali’s other volcano, Mount Batur.

Bali's Mount Agung volcano spews plume of ash 6,000 metres into the sky

When did it last erupt?

The last eruption occurred in February of 1963, and lasted almost a year.

What happened?

The 1963 eruption was one of the largest and most destructive in the country’s history. It destroyed countless villages and killed an estimated 1,600 people. Minor eruptions and pyroclastic flows continued on the island for months. About 280 million m3 of magma was ejected from the mountain over that time period, and lava travelled as far as 14km to the south.

The deadliest effects of the eruption, however, were the pyroclastic flows. The waves of superheated gas can travel hundreds of kilometres per hour, and carry ash and rock with them. The flows caused most of the deaths resulting from the 1963 event.

Mount Agung volcano – in pictures Show all 8 1 /8 Mount Agung volcano – in pictures Mount Agung volcano – in pictures The Mount Agung volcano spews hot volcanic ash, as seen from Datah, Karangasem, Bali, Indonesia. According to media reports, the Indonesian national board for disaster management raised the alert for the Mount Agung volcano to the highest status and closed the Ngurah Rai International Airport in Bali due to the ash cloud rising from the volcano EPA Mount Agung volcano – in pictures A long exposure photograph shows the Mount Agung volcano spewing hot volcanic ash as seen from Amed, Karangasem regency, Bali, Indonesia. EPA Mount Agung volcano – in pictures A villager walks as Mount Agung volcano erupts in the background in Kubu, Karangasem, Bali, Indonesia Reuters Mount Agung volcano – in pictures Women wait for customers at a market as smoke rises from the Mount Agung volcano AP Mount Agung volcano – in pictures Vegetable sellers wait for customers at a market with Mount Agung erupting in the background AP Mount Agung volcano – in pictures Balinese people ride on an open car past Mount Agung erupting seen from Kubu sub-district in Karangasem Regency AFP/Getty Mount Agung volcano – in pictures Villagers rest at a makeshift tent at an evacuated area in Karangasem AP Mount Agung volcano – in pictures Evacuees stay at an emergency shelter in Klungkung, Bali EPA

What has happened so far?

Experts raised the alarm about Mount Agung this September, when they detected an increasing number of earthquakes happening under the volcano’s surface. Not long after, the volcano began emitting smoke and ash.

The volcano alert status on the island has now been raised to its highest level. Mudflows have been seen running down the mountain, and villagers have reported hearing booming sounds.

Approximately 100,000 people have been told to evacuate the area nearby. The airports on the island have also been closed, leaving thousands of travellers stranded. In other countries, governments have warned travellers to steer clear of the popular tourist destination.

What could happen?

The jury is still out on exactly how big the eruption will be – or if it will even happen. Diana Roman, a geologist at the Carnegie Institution of Washington, told the Washington Post that scientists “do not have any basis for knowing whether this eruption will intensify, continue at its current level, or stop”.

If the eruption is large, it would be a major problem for the island’s inhabitants, who depend largely on tourism and agriculture to survive. Already, some airlines are allowing customers to change or refund their tickets to the island.

On the bright side, volcanic eruptions can actually cool the Earth’s temperature. Teresa Ubide, a lecturer in volcanology from the University of Queensland, told the Guardian that this is due to sulphuric emissions from the volcano. The sulphur-based aerosols block radiation from the sun, thereby lowering global temperatures.