The aviation alert for Bali’s rumbling Mt Agung volcano has been upgraded to orange as the island was Tuesday hit by an earthquake felt in holiday resorts.
The Volcano Observatory Notice for Aviation (VONA) was upgraded from yellow as a low-pressure white plume “likely dominated by water vapour” was observed emitting continuously from the main crater.
The notice said an ash cloud was not visible.
“Plume is observed emitting continuously from the main crater and reached an altitude of approximately 500 m and moving Northeast,’’ the notice posted by Agung Volcano Observatory said.
“Based on our visual and instrumental observation, Agung volcano is exhibiting heightened unrest with increased likelihood of eruption.”
An orange alert is the second highest and means the volcano is exhibiting heightened unrest with increased likelihood of eruption or that an eruption is underway with no or minor ash emission.
It will be upgraded to red if volcano starts spewing ash or experts believe that it will start doing so.
Ash can significantly damage jet engines and, if it is dense enough, force them to shut down.
A British Airways Boeing 747 flying from London Heathrow to Auckland lost all four engines when it flew into a volcanic ash cloud near Jakarta in 1982. The aircraft glided out of the cloud and the crew managed to restart the engines and land in Jakarta.
Tuesday’s earthquake measured 4.2 on the Richter scale and was felt as far away as the tourist hotspot of Kuta. It was estimated to be about 5km deep and comes after volcanic tremors have been increasing in frequency as magma pushes towards the surface.
“This further cements our belief that an eruption is about to happen,” Indonesia’s Centre for Volcanology and Geological Disaster Mitigation chief Kasbani told The Australian.
Flights to Bali are still operating but more than 75,000 people have now been evacuated from the area around Mt Agung .
Airlines had yet to upgrade their travel alerts early Wednesday although Virgin Australia has re-routed some Bali-Bound flights via Darwin to pick up extra fuel. It says this will allow aircraft to turn back to Australia if the volcano erupts while they are en-route to Denpasar.
Both of Australia’s major airline groups say they are monitoring the situation closely and travellers have been urged to make sure their contact details are up to date. School holidays are currently underway in Australia and this is a peak travel period for holidaymakers heading to the island.
The Australian Government has also warned air travel to Bali could be affected by an eruption and Bali’s international airport has set up an emergency operations centre.
Travel insurance companies began imposing restrictions on policies after warnings about the potential eruption became public. This means people who bought travel insurance after a certain date will not be covered for losses relating to the volcano.
The dates vary according to insurance company but a list on finder.com.au has cut-off dates ranging from September 16 to September 22.
Mt Agung’s last major eruption was in 1963 and killed more than 1100 people. That eruption lasted for more than a year.