Bali's Mount Agung volcano could erupt at any moment for the first time in 54 years, with the warning level upgraded to the highest possible level at 8.30pm on Friday, local time.
People have been told to evacuate from within a nine to 12 kilometre radius of the summit after smoke was seen rising 100 metres from the summit.12 kilometre radius of the summit after smoke was seen rising 100 metres from the summit.12 kilometre radius of the summit after smoke was seen rising 100 metres from the summit.12 kilometre radius of the summit after smoke was seen rising 100 metres from the summit.
The airport is still operating but a series of tremors increasing in intensity has shaken the area surrounding Mount Agung since Friday morning, with more than 10,000 residents choosing to evacuate.
The volcano, which is is located in eastern Indonesia, about 71 kilometres from the tourist destination Kuta, last erupted in 1963, killing 1100 people.is is located in eastern Indonesia, about 71 kilometres from the tourist destination Kuta, last erupted in 1963, killing 1100 people.is is located in eastern Indonesia, about 71 kilometres from the tourist destination Kuta, last erupted in 1963, killing 1100 people.
The Volcano Observatory Notice for Aviation said seismic activity showed a tremendous increase in numbers and activity.
"This number of seismicity is an unprecedented seismic observation at Agung volcano ever recorded by our seismic networks," it said in a statement.
It said its monitoring data and analysis indicated an increased probability of eruption but it could not estimate exactly when it would take place.
The Australian Department of Foreign Affairs issued an updated travel warning for Indonesia that said an eruption could impact air travel in the region.
"Contact your airline or tour operator to confirm travel plans," it said.
It also warned Australians to monitor local media and follow the instructions of local authorities.
National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho announced on Friday night the warning level had been raised from standby (level three) to danger (level four).
"With the expansion of the hazardous zone area the refugees will increase " he said.
"The development today is quite extraordinary, the intensity of it," said the head of the Centre for Volcanology and Geological Hazard Mitigation Kasbani.
He said the evacuation from the affected area should begin immediately.
However Mr Sutopo told people to "calm down" and not be provoked by misleading information. He did not specify what misleading information he was referring to.
"Until now Mount [Agung] has not erupted. Monitoring has intensified."
The exclusion zone of nine to 12 kilometres is likely to affect more than 100,000 people living in the shadow of the volcano.
About 500 tremors were recorded in the region of Mount Agung on Friday between 6am and 6pm local time alone, with the highest measuring 3.6. The tremor was 29 kilometres deep.
Evacuees, who are living in tents or sports centres, need assistance with nappies, sanitary napkins and baby food. There is also a huge demand for public toilets.
Locals were reportedly attempting to sell their cattle for half the usual price as of Friday morning before evacuating.
Emeritus Professor Richard John Arculus from the Australian National University wrote that although infrequent, eruptions of Mount Agung have been among the largest of the past 100 years of global volcanic activity.
"Mount Agung is one of many similar volcanoes in Indonesia and the ring of fire surrounding the Pacific and eastern Indian oceans," he wrote in upi.com.
"But during its sporadic eruptions, Agung has been one of the most prominent injectors of volcanic ash and sulphur dioxide into the atmosphere."
Professor Arculus said the ability to predict eruptions had improved dramatically and it was hoped the high death toll of 1963 would not occur again.
That particular eruption was also preceded by earthquakes. Lava and small explosions of volcanic ash began in February leading to a major explosion on March 17.
There was an eruption of similar intensity in 1843 and several in the 16th to 18th centuries.
