Big Bang Theory: scientists size up the volcano that rocked Mount Gambier
Volcanic ash plumes rising up to 10 kilometres high, health risks to humans and an impact zone of up to 100 kilometres radius.
It sounds like the plot for the latest Hollywood disaster blockbuster, but it's actually the results of findings from scientists studying the historic Mount Gambier volcanic eruption and what we could expect, should it happen again.
In spite of being over 5000 years old, the crater that holds the Blue Lake, currently holds the title of Australia's most recently active volcano.
Researchers from Monash University's Volcanology Research Group have used 3D geometrical computer modelling and thermodynamics to determine the size and magnitude of the eruption that shook the foundations of Mount Gambier.
Dr Jozua van Otterloo and Professor Ray Cas, from the School of Geosciences, estimated the volcano would have registered as a size 4 eruption on the Volcanic Explosivity Index, a similar size to the Eyjafjallajull eruption in 2010.
The eruption in Iceland caused significant global impact as ash plumes closed down international airspace, caused earthquake activity and saw flooding as far as Northern Scotland.
Eyjafjallajull last erupted in 1821, a mere 190 years before its most recent activity.
Leading author of the study, Dr van Otterloo said the Mount Gambier eruption was particularly violent because magma buried up to 80 kilometres, rose to the surface and forcibly joined with shallow groundwater, causing a volatile reaction.
Dr van Otterloo said it was unlikely the Blue Lake crater could erupt into volcanic activity again because it was known as a monogenetic volcano, or one that only erupts once in its lifetime.
But he said the volcano is part of a larger province known as the 'Newer Volcanics', a band that stretches between Melbourne and Mount Gambier, which was still considered an active province.
Using the example of the Mt Schank volcano just 14kms from Mount Gambier, Dr van Otterloo said volcanos were known for erupting close to previous sites.
"The province has over 400 eruption centres and has been active for at least 4 to 5 million years," he said.
"We don't have to worry that it will erupt anytime soon like tomorrow or the day after but we should be aware that there could be another one to come."
"But when and where is unknown."
Dr van Otterloo said an eruption of similar size in the region would cause a major impact across the east of Australia and possibly further afield.
'Livestock and crops would be covered in ash, air travel would be impacted and the ash could rise up and spread all over Melbourne, Canberra and Sydney, possibly even New Zealand."
Dr van Otterloo said his team would continue their studies around the region to further provide insight into the elusive phenomena but said people should be aware that it could happen.
"Although statistics tell us it could be a long time before the next eruption, the main hazard is that when it does, we will only have a few days warning."
The study has been published in the Bulletin of Volcanology.
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