NEW research into the age of volcanoes has verified that western Victoria is overdue for an eruption with the potential to cause widespread destruction.
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Scientists from the University of Melbourne have calculated the ages of the small volcanoes in the south-west Victoria and south-east South Australia region and found the recurrence rate for eruptions to be 2000 years.
With the last volcano eruption at Mount Gambier occurring more than 5000 years ago, scientists say the areas are overdue.
The research was presented yesterday by Professor Bernie Joyce at the International Congress of Geodesy and Geophysics in Melbourne.
“Although the volcanoes in the region don’t erupt on a regular sequence, the likelihood of an eruption is high given the average gap in the past has been 2000 years,” Professor Joyce said.
“These are small eruptions and very localised, but depending on the type of eruption, they could cause devastation to thousands of people.”
The wider area demonstrates a history of activity by young monogenetic (single, short-lived activity) volcanoes.
Professor Joyce and his colleagues from the University’s School of Earth Sciences have spent years cataloguing the hundreds of small volcanic cones, lava flows and craters in the region.
The distribution of activity, including lava flows and ash deposits, has been mapped in detail.
The latest findings come after more recent studies using a range of state of the art dating techniques, which have provided more information on the ages of the individual volcanoes and the occurrence rates.
Professor Joyce said communities need to have some knowledge of what to do after an eruption.
“So far we have no action plans in place if eruptions occur,” he said.
“If they happen close to Melbourne or Geelong, it could be hugely devastating. It is more likely, however, that eruptions would occur further west, closer to areas such as Colac, Port Fairy, Portland and Mount Gambier.
“Among the hazards which may need to be prepared for in this closely-settled region are the localised effects of cone building leading to lava flows which run downhill towards the coast.
“The long lasting and often extensive lava flows can travel for tens of kilometres and so would be hazardous to modern infrastructure such as bridges, roads and railways, powerlines and pipelines, as well as being a major fire hazard on the dry grassland plains of summer in western Victoria.”
“In some cases rising magma can meet ground water and cause steam explosions. This can form wide craters and produce a lot of ash.”
sfowles@standard.fairfax.com.au
