Bali on high alert as Mount Agung tremors signal imminent eruption

Ngurah Rai International Airport in Denpasar on Monday after the airport was closed following the eruption of Mount Agung
photo: supplied
Ngurah Rai International Airport in Denpasar on Monday after the airport was closed following the eruption of Mount Agung photo: supplied

Bali is on high alert as the imminent eruption of Mount Agung draws closer, with authorities warning the volcano could erupt within hours.

It followed reports on Tuesday evening of a 30 minute termor inside the crater which followed on from a series of small eruptions that began last week.

Holidaymakers are set to spend at least another day stranded in Indonesia, with authorities announcing the airport would remain closed a further 24 hours as volcanic ash clouds ground flights in and out of Bali.

Indonesian authorities closed Ngurah Rai International Airport in Denpasar on Monday morning and ordered people within 10 kilometres of the erupting Mount Agung to evacuate after raising the alert to level 4 - the highest level.

More than 100,000 residents within the exclusion zone were ordered to evacuate on Monday, as warnings suggested that the first major eruption in 54 years could be "imminent".

Eruptions from Mount Agung - which lies just over 72 kilometres from Kuta - have sent volcanic ash and steam up to four kilometres into the skies above the summit, and authorities have warned that larger eruptions could occur at any moment.

Qantas, Jetstar and Virgin Australia advised passengers on Tuesday that all flights were cancelled for the day.

Meanwhile, Denpasar airport has confirmed it will remain closed until at least 7am Wednesday local time.

A report from local aviation navigation authorities showed that "aircraft flight channels are covered with volcanic ash", the ministry said in a statement.

Ten alternative airports have been prepared for airlines to divert inbound flights, including in neighbouring provinces. A separate notice showed Lombok airport had been reopened, after an earlier closure overnight due to the eruption.

There are 22 villages within 10 kilometres of Mount Agung's crater, which are home to about 100,000 people, the National Disaster Mitigation Agency said.

More than 40,000 people have already fled their homes because of the volcano, according to the agency.

Plumes of smoke were billowing out of the mountain top and explosions could be heard up to 12 kilometres from the peak.

"Rays of fire are increasingly visible from night to the following day. This indicates the potential for a larger eruption is imminent," the agency said.

Agung's last eruption in 1963 killed more than 1,000 people and razed several villages by hurling out pyroclastic material, hot ash and lava.

Yet on Tuesday, life continued largely as normal in villages surrounding Agung, with residents setting up traditional markets and offering prayers as the volcano continued to spew tall columns of ash and smoke from its crater.

Many residents who evacuated in September when the alert was last raised to the highest level have returned to their homes and farms due to worries over their livelihood and livestock.

Indonesia's Volcanology and Geological Disaster Mitigation Centre (PVMBG), which is using drones, satellite imagery and other equipment, said predictions were difficult in the absence of instrumental recordings from the last eruption 54 years ago.

It warned that if a similar eruption occurred, it could send rocks bigger than fist-size up to 8 km from the summit and volcanic gas a distance of 10 km within three minutes.

The smoke has caused chaos for travellers hoping to leave the country - Denpasar airport said in a statement that 445 flights and 59,000 passengers had been affected on Monday alone.

Two Australian travellers returning to Melbourne, Hena and Joshkun, were among hundreds who amassed at the airport on Monday, after being unable to change their Jetstar flight online.

"We tried contacting the airline, that didn't work either," Hena said.

"I am a dancer - I have shows, so I am missing rehearsals."

The Indonesian Hotel and Restaurant Association said guests of affiliated hotels who were stranded by the airport's closure would be accommodated on Monday night free of charge.

According to the Australian Bureau of Meteorology's Volcanic Ash Advisory Centre (VAAC) in nearby Darwin, there is "ash confirmed on the ground at Denpasar Airport" as well as ash at "FL300" - which refers to flight level at 30,000 feet - in the vicinity of the volcano.

Airport spokesman Arie Ahsan said the airport closure was based on information from VAAC and the Indonesian Agency for Meteorology, Climatology and Geophysics.

"The ash is very light in the airport buildings but what effects flights would be the thickness in the air," he said.

Buses were being used to get a mixture of Indonesian and foreigner passengers to Padang Bai port and other destinations.

"The authorities will meet every six hours to evaluate the conditions. We can't predict the outcome," he said.

Airlines have set up customer service desks at the international terminal. A Jetstar staff member said that not many passengers had arrived because most already knew that the airport was closed and that there were no flights out. Those who had come had booked through travel agents and didn't know.

???Volcanic ash poses a potentially deadly threat to aircraft and passengers.

Mount Agung is just over 72 kilometres from Kuta, and towers over eastern Bali at a height of just over 3000 metres.

Indonesian National Board for Disaster Management spokesman Sutopo Purwo Nugroho said on Monday any further eruptions will not be as big as in 1963 because there was less magmatic energy.

Bali, famous for its surf, beaches and temples, attracted nearly 5 million visitors last year but business has slumped in areas around the volcano since September when Agung's volcanic tremors began to increase.

with AAP, Reuters

This story Bali on high alert as Mount Agung tremors signal imminent eruption first appeared on The Sydney Morning Herald.