Australian team readies for Bali’s Mt Agung eruption

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The likely eruption of Bali’s Mount Agung has “potential for major impacts” depending on the scale of the explosion, according to a member of a team at Australia’s Bureau of Meteorology that is preparing to assess the impacts of whatever ash cloud is thrown up by the volcano.

Emile Jansons, an aviation services manager at the Volcanic Ash Advisory Centre (VAAC), said the latest advice is that an eruption is likely given evidence that molten rock, or magma, is rising within the mountain, causing deep volcanic earthquakes.


Bali’s volcano ready to erupt

Thousands are evacuated as tremors and smoke billow from the mouth of the Mount Agung volcano, which is 71km from tourist hot spot Kuta.

“It might be a very explosive one, it could be a weak eruption that lasts for a long time, and it’s also entirely possible that it just stops,” Mr Jansons said. 

Mr Jansons is part of a team that works within the bureau, monitoring the potential for ash clouds that may disrupt air travel in the region.

While the group’s mandate is specifically to advise airlines, the team also works with agencies on the ground given the damage ash – a mix of pulverised rock, minerals and even glass – can cause to areas unlucky enough to be under it.

Falling ash, for instance, can crush buildings, affect lava flows and trigger mudslides and other hazards, he said.

While typically in the public eye only during big volcanic activity in the region, the VAAC team is active 24 hours a day, around the year. The group is responsible for monitoring about 160 volcanoes known to be active or have blown in the past 10,000 years.

Its coverage is part of nine such centres around the world, set up after a Boeing 747 aircraft operated by British Airways lost power from all four of its engines after flying through a volcanic ash cloud en route to Perth from Kuala Lumpur in 1982. 

The aircraft glided from a height of about 11,000 metres to about 4,100 before the crew managed to get the first of eventually all four engines restarted, but the scare was enough to prompt the civil aviation industry to set up a global watch.

For the Australian team, formerly based in Darwin before a transfer to Melbourne in 2014, the monitoring extends from southern India, across all of Indonesia – home to more active volcanoes than another other nation – to parts of the Philippines and the south-west Pacific. (See chart below.) 

Mr Jansons said improved satellite technology combined with advancing meteorology and other sciences means advice for airlines is much more precise than in the past. 

Of course, such information is only available once a volcano blows.

“If you are in airspace directly above the volcano when it erupts, you can have very serious impacts on the engines,” he said.

That ash can soften, accumulate and stick on the turbine components. Cooling can be affected, as can the combustion process, altering or even stopping thrust and causing “a flame out” when the engine stops working.

Windshields of aircraft can also be abraded by the ash, while airframe coatings can also be eroded, Mr Jansons said. Planes can also have their auto-pilot functions affected, with devices tracking air speed thrown off kilter.

The Australian group issues about 3000 advisory notes a year about volcanoes. Apart from Mount Agung, there are several other volcanoes being closely monitored now, such as one erupting in Papua New Guinea.

The area to Australia’s north and east include sections of the so-called Ring of Fire of active volcanoes. (See US Geological Survey chart below.)

The impacts of volcanic ash can depend in part on the time of year.

An eruption during the middle of the dry season can see the ash travel much further, while one during the wet season can see it deposited much faster, Mr Jansons said. Bali is now coming to the end of its dry season.

Big eruptions, such as Mount Tambora on Indonesia’s Sumbawa Island, can also have an impact on the global climate.

An explosion of that mountain in 1815 ejected an estimated 160 cubic kilometres of material that would later be blamed from ruining crops across the northern hemisphere.

Volcanic eruptions usually include sulphur dioxide and other particles that can reflect sunlight back to space, cooling the climate, Mr Jansons said.

graphic

Mount Pinatubo’s eruption in 1991, for instance, sent material as high as 35 kilometres.

It’s up to airlines to weigh the risks of flying near ash clouds, with carriers at times responding differently to the same advice, Mr Jansons said.

“Sometimes it makes more sense to fly through a small amount of ash, knowing that it won’t cause any safety problems at all for your engine,” he said.

While the day-to-day monitoring can be fairly regular for his team, interest from the media and the public tends to spike when a volcano threatens to blow near heavily travelled routes.

“Everyone wants to call up to know if they can get to a wedding, but we just can’t help them,” Mr Jansons said. “We have to say sorry” but check with your airline.



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