Australian volcanoes overdue an eruption warn scientists

By Colin Ricketts - 06 Jul 2011 20:2:0 GMT
Australian volcanoes overdue an eruption warn scientists

The people of Australia have been warned that volcanoes in Western Victoria and South Australia are overdue for eruptions potentially affecting thousands of people.

A team from the University of Melbourne's School of Earth Sciences and the Melbourne School of Engineering used the latest techniques to date small volcanoes and have found that eruptions should occur once every 2,000 years.

That means, that Mount Gambier, which last erupted over 5,000 years ago, is long overdue a blow-out.

"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 2,000 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," he said.

The volcanoes in Western Victoria and adjacent south-eastern South Australia are young monogenetic (single short-lived activity) volcanoes and this type of volcano is also found in northeast Queensland.

They offer several threats to populations said Professor Joyce.

"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, power lines 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."

"Depending on where the eruption occurs, ash can cause huge damage to people who are down wind, clogging up streams, road and rail transport and perhaps affecting local air travel," he said.

The Australian tectonic plate is on the move say the scientists.

"The plate is hitting up against PNG, lifting the southern margin upwards. This allows magma to move upwards towards the surface," Professor Joyce said.

He is concerned that no plans are in place to deal with eruptions or seismic activity.

The research was presented by Professor Joyce at the XXV International Congress of Geodesy and Geophysics (IUGG) yesterday.

Top Image Credit: © Athol Abrahams