General view of the Mount Agung in Bali, which threatens to explode on Friday 22 September 2017.
Indonesia, an archipelago of thousands of islands, is prone to seismic upheaval due to its location on the Pacific "Ring of Fire", an arc of volcanoes and fault lines encircling the Pacific Basin. Many of these show high levels of activity but it can be weeks or even months before an actual eruption.
More than 122,000 people on the Indonesian resort island of Bali have sought refuge in temporary shelters amid fears that the Mount Agung volcano will erupt soon.
The transportation minister said on Wednesday that Bali-bound flights could be diverted to 10 airports across the country in case of an eruption. On the surface, a low emission of white smoke above the volcano is visible.
Another volcano, Mount Sinabung, has been erupting sporadically since 2010, sometimes blasting volcanic ash several kilometres into the air and forcing more than 30,000 to evacuate their villages.
Disaster officials are now working with the police, the military, and aid organizations like the Red Cross to dispatch vehicles filled with food, water, blankets and other necessities to evacuation centers.
Australia was also funding surveillance flights over the volcanoes on Ambae and nearby Ambrym island, it added. The exclusion zone around the volcano extends in some parts as far as 12 kilometers (7.5 miles), but officials said people farther from the mountain are leaving too. He evacuated with this elderly mother, wife, children and young grandchild to the Swecapura sports arena. But officials now said people are fleeing even farther areas.
Bali's Ngurah Rai International Airport is the second-busiest in the country, after Jakarta's main international airport.
Agung last erupted in 1963, killing about 1,100 people.
"I don't know where my kids will sleep and all I can do now is pray", said Gusti Gege Astana, 40.
Balinese man watches Mount Agung volcano nearly covered with clouds as he stands at a temple in Karangasem, Bali, Indonesia, Tuesday, Sept. 26, 2017.