Should Australia Expect A Volcanic Eruption?

Australia has the longest chain of continental volcanoes in the world.

When you think of Australia, words like eruption, lava and magma aren’t usually what you think of.

However, not only does Australia have a large chain of volcanoes, that stretch from Melbourne to Mount Gambier, but they could still be considered active.

The Blue Lake in Mount Gambier and Mount Schank are Australia’s most active volcanoes, erupting over 5,000 years ago. Having said this, volcanoes have an eruption frequency of an estimated once every 10,000 years, so any volcanic activity is fairly unlikely.

However, Jozua van Otterloo, an assistant lecturer in volcanology, at Monash University,  predicts another eruption will occur in the next 5,000 years.

"It's very hard to estimate when a volcanic eruption is going to be in south--east Australia, because it's such a large area," Dr. van Otterloo explains to the ABC.

"But the last eruptions were Mount Gambier and Mount Schank, so we could expect another volcanic eruption in that area."

He believes that if a volcano erupts, there will be no warning signs, as the magma will need to rise to the surface quickly, with perhaps only two days’ notice.

Mount Gambier’s Blue Lake, a maar volcano, formed from magma rising through Earth’s crust.

Image: The Blue Lake, Mount Gambier. Photo taken in March 2004, 

"As it rose through the crust, it somehow hit groundwater," Dr. van Otterloo told the ABC.

"The groundwater just sits there, and as it mixes with that groundwater it becomes very, very explosive, and it just excavates a big hole in the ground, which gives us that big crater, which we call a maar."

These volcanoes are different from those found in the chain on Australia’s east coast.

“Some volcanoes that we deal with in eastern Victoria, there's a bit of an alignment of some of the volcanoes, and the ones in the north are older than the ones in the south. That's because Australia's plate moved northward over a very hot area in the mantle (the part of the Earth underneath the crust).”

Essentially, when Australia moves northward, there is a line of volcanoes running north to south on the east coast, but when it shifts from the hot area, the heat disappears, leaving the volcano dormant.

"Australia and Antarctica were once connected as one continent," Dr. van Otterloo said to the ABC.

"Then, as that was broken apart, the crust in south-eastern Australia has thinned, so it's become thinner to the north of it on the mainland. That causes hot material from the mantle to just bulge up very shallowly, and that causes volcanism to occur. So Australia deals with two different types of causes for volcanism over time."

Lead Image: National Geographic

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