Scientist says eruption long overdue

CANBERRA - So much for the Shaky Isles. Australia, already becoming increasingly aware of its vulnerability to earthquakes, has now been warned to prepare for volcanic eruptions.

A leading scientists says that the nation should be taking a leaf out of New Zealand's book of horrors and follow Auckland Regional Council's example of creating a web page dedicated to the danger.

Geologist Bernie Joyce said Auckland had an eruptive history very similar to Australia's.

He said an Australian eruption was now overdue and some potential volcanoes could spew ash on to Melbourne and pump lava into the streets of Australia's second-biggest city.

Lava - possibly lasting 20 years - and explosive ash could decimate important grassland plains, cutting off essential water supplies and destroying towns, farmland, roads, railways and bridges.

Toxic gases could also settle in depressions in the surrounding countryside and asphyxiate anyone caught there.

Joyce is an internationally-known geologist who on Thursday will receive the Victorian division of the Geological Society of Australia's Selwyn Medal, awarded for outstanding contribution to the science.

Joyce's volcano warning follows research that has shown Australia is rocked by an average 200 earthquakes of magnitude 3.0 or more every year, and by quakes of magnitude 5.5 - such as the one that killed 13 people and damaged 50,000 homes in Newcastle in 1989 - on average every two years.

Volcanoes are something else again.

There are only two active volcanoes on Australian territory: "Big Ben" on Heard Island in the depths of the Southern Ocean, and Mawson Peak on nearby McDonald Island, whose eruptions doubled the island's size in the final two decades of the last century.

But in a warning issued through the Geological Society and sciencealert.com.au, Joyce said that a volcanic eruption on the Australian mainland was an inevitability.

In the past 40,000 years there had been a cycle of increased volcanic activity that could be pointing to future events.

"We can't say with 100 per cent certainty that a significant volcano will strike tomorrow, next week, next year, or even 100 years down the track, but these geohazards are real and they must be given much more focus by emergency management authorities," he said.

Joyce said there were about 400 volcanoes stretching from Victoria's western district into the western uplands around Ballarat, and to the north of Melbourne, and in some parts of the eastern uplands, stretching into South Australia near Mt Gambier.

An eruption in the western uplands could threaten Melbourne.

Similar threats existed in far north Queensland, reaching from southwest of Townsville to near Cairns, and up to Cooktown.

Joyce said there were more than 380 volcanoes in this region.

Any eruption was unlikely to blow from an existing volcano.

Instead, they would blast from nearby sites.

"The geological records show that new volcanoes in these areas have erupted perhaps every 200 years in the past 40,000 years - and given there has not been a major eruption there for the past 5000 years, a significant eruption seems well overdue," Joyce said.

"While any future volcanoes may discharge only small amounts of lava and ash, the real possibility remains that there could be a significant eruption.

"It makes sense that the population centres potentially affected should be well prepared for that worst-case scenario."

Joyce said response plans should be developed and publicised by emergency management authorities, as had been done in New Zealand.

"It is much more likely to be a matter of when, not if, a significant volcano occurs in Australia, and emergency authorities should be better preparing themselves and the wider community for that eventuality."