Scientists have solved a long-standing mystery surrounding Australia’s only active volcanic area around Mt Gambier in South Australia and east toward Melbourne.
The 500 kilometre long region stretches from Melbourne to Mount Gambier and surrounds a dormant volcano which last erupted 5,000 years ago.
“Volcanoes in this region of Australia are generated by a very different process to most of Earth’s volcanoes, which occur on the edges of tectonic plates, such as the Pacific Rim of Fire,” says lead researcher Dr Rhodri Davies of the ANU.
“We have determined that the volcanism arises from a unique interaction between local variations in the continent’s thickness, which we were able to map for the first time, and its movement, at seven centimetres a year northwards towards New Guinea and Indonesia.”
The volcanic area is comparatively shallow, less than 200 kilometres deep, in an area where a 2.5 billion-year-old part of the continent meets a thinner, younger section, formed in the past 500 million years or so.
These variations in thickness drive currents within the mantle, which draw heat from deeper up to the surface.
The researchers used state-of-the-art techniques to model these currents on the NCI Supercomputer, Raijin, using more than one million CPU hours.
It is difficult to predict where or when future eruptions might occur, Dr Davies said.
“There hasn’t been an eruption in 5,000 years, so there is no need to panic,” he said. “However, the region is still active and we can’t rule out any eruptions in the future.”
The research is published in the journal Geology.
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