It could be just a “matter of hours” before Mount Agung in Bali erupts, as the area is experiencing unprecedented levels of seismic activity, Indonesia’s volcanology centre said, according to The Guardian.

More than 75,000 people were evacuated over the past few days as Agung has experienced hundreds of internal volcanic earthquakes. Data showed that Mount Agung had 844 volcanic earthquakes on Monday and around 400 by midday on Tuesday, Devy Kamil Syahbana, a seismologist from Indonesia’s centre for volcanology and geological hazard mitigation, said.

“We need to pay attention because these kinds of earthquakes indicate the movement of magma and increase the probability of an eruption,” he warned. According to the seismologist, the centre has never recorded such high energy from Mount Agung.

There have been tremors around the mountain since August, as the volcano on the tourist island threatens to erupt for the first time in 50 years. The last time it erupted in 1963, more than 1,000 people were killed.

Evacuation on, travel advisories issued

Indonesian authorities arranged makeshift shelters in town halls and school gymnasiums and set up tents in villages around the volcano to house thousands of evacuees. Vehicles loaded with noodles, mineral water and blankets have been sent to the evacuation centres, and residents around the island have been collecting donations, AFP reported.

Several countries, including Australia, Singapore and the United States, issued travel advisories alerting holidaymakers to the risk, Reuters reported.

Indonesia has nearly 130 active volcanoes along the Pacific Ring of Fire – more than any other country in the world.