There are Several Volcanoes Quietly Simmering Under Melbourne

Right now, a number of active volcanoes are asleep under the city of Melbourne. One of them is located beneath the metropolitan centre; a second buried in the western suburbs; while a third sits, simmering, under Tullamarine International Airport. More than 400 others are littered throughout south-eastern Australia: part of a 15,000 square kilometre volcanic field known as the Newer Volcanics Province. And they could erupt at any moment.

Like Hawaii’s Kilauea volcano—which has seen hundreds of homes destroyed and thousands of people evacuated as the result of an ongoing eruption over the past few months—the Australian volcanoes are positioned within the centre of a tectonic plate. The Melburnian volcanoes haven’t erupted in over a million years, and the most recent activity to take place within the NVP was an eruption at Mt Gambier some 5,000 years ago, according to an article published in The Conversation.

Researchers Jozua van Otterloo and Ray Cas from Monash University, alongside Heather Handley from Macquarie University, insist that the magmatic field is still very much active, however—and that no one is entirely sure when Australia’s next volcanic event might occur.

“We do not know when the next eruption will take place,” they admit. “If the NVP were to erupt, significant impacts on our lives would likely occur.”

A non-exhaustive list of those potential impacts includes lava flows on public roads, damage to electricity infrastructure, contamination of water reservoirs, and breathing complications for anyone suffering from asthma. To say nothing of the toxic ash and fumes.

"If an eruption happens in metropolitan Melbourne, it will of course be disastrous for anyone living or having a business in the immediate vicinity," Dr van Otterloo, Assistant Lecturer in Volcanology, told VICE. "Lava flows will block infrastructure and severely damage, if not demolish, buildings. If it becomes more explosive, which is possible in the areas closer to the Bay, ground-hogging ash and steam clouds will blast and cover areas up to 5 square kilometres.

"Ash clouds will cover a larger area that will produce health hazards to anyone in a downwind direction and stop air traffic."

Van Otterloo stresses that while we can't rule out the possibility of an event like this occurring in Melbourne, the likelihood of an eruption happening in the near future is "very, very small." More probable, he says, is the chance that some kind of volcanic event will take place further west. That would still pose "a major hazard from volcanic ash when the eruption becomes very explosive", however—"especially since Melbourne is in the general downwind direction from western Victoria".

The slightly more positive news is that Australia’s volcanoes aren’t as big as many others around the world, and contain a relatively small amount of magma. The highest one, according to a research paper published by the University of Melbourne's School of Earth Sciences, is Mt Elephant in Victoria's southwest, which sits at an elevation of 393 metres above sea level. Kilauea's elevation is 1,247 metres.

Furthermore, the continental crust layered on top of the NPV is about 30 kilometres thick: making it significantly harder for that magma to make its way to the surface. "There are some studies showing a hotter, or more liquid zone under Mt Elephant," says van Otterloo. "However, the crust in this area is very thick, so even if there is magma there, it can't really travel up to surface easily."

In any case, the researchers declare that the volcanic field stretching across Australia’s south-east needs to be more closely monitored in order to minimise the threat of a potential natural disaster.

"The risk is by far not high enough to increase insurance policies and preemptively evacuate the area," says van Otterloo. "But the government should at least develop a risk and hazard plan, as well as put some money in monitoring and further researching this area.

"A volcanic eruption will one day occur again in the area. Maybe not in our lifetime, but people have been around at some of these eruptions in the past, so most likely people will be around when it happens again next."