Professor Ray Cas says a new volcano could erupt in western Victoria any time soon and he should know.
Professor Cas, of Monash University, is a world-renowned volcanologist and says the western Victoria volcanic province is still active.
This month he gave a public talk in Hamilton about the lively past of western Victoria’s volcanoes.
His talk might not have sent the audience rushing to safer ground, but it did give it a deeper respect for the region’s former hot spots.
Professor Cas said volcanic activity began six to eight million years ago in the “Newer Volcanic Province” that extends from Melbourne across western Victoria and into south-eastern South Australia.
There are more than 400 small individual volcanoes throughout the province with the last one occurring at Mount Gambier about 5000 years ago.
On average, a volcano has erupted in the province every 15,000-20,000 years, he said.
With the last volcano occurring 5000 years ago, it was likely there would be another within the next 15,000 years.
“It could be in two weeks, it could be in 100 years or it could be in 5000 years,” Professor Cas said.
He studied the “Newer Volcanics Province” for a paper that was published in the Journal of the Geological Society of London.
He believes that since the most recent eruption in the province was in the west at Mount Gambier, it was likely the next eruption would also be in the west of the province.
If the next volcano was like the one that formed Tower Hill, it was likely to send ash east across a vast area that extended not only to Melbourne, but also to Canberra, Sydney and New Zealand, disrupting air traffic and business.
But his analysis of the eruption styles of volcanoes in the province found there were no particular trends in the manner in which they erupted.
Professor Cas is particularly impressed with the lava flow from the volcano that is now Mount Napier, south of Hamilton.
Mount Napier is the highest volcano in the province and lava from it flowed through Harman’s Valley near Byaduk.
Professor Cas said the Harman’s Valley lava flow was about 46,000 years old and had retained many of its original features despite eons of weathering.
Those features were similar to the volcanic ones found in Hawaii that has three active volcanoes.
He said the Harman’s Valley lava flow was an important natural laboratory for scientific work on volcanoes in Australia and he was disappointed a local farmer crushed some of it in 2016.
Professor Cas this month spoke to a Planning Panels Victoria hearing in Hamilton in favour of imposing a permanent Significant Landscape Overlay (SLO) on the Harman’s Valley lava flow and surrounding volcanic areas to protect them from development such as rock crushing.
He believes volcano geo-tourism could replace some of the economic benefits that might be lost by limiting farming activities in the proposed SLO area.
He said better signage at other south-west volcanic sites such as Mount Rouse and Mount Elephant could awake a lot of interest, not only from tourists but also from locals, in the region’s volcanic nature.