Massive ancient landslides found under sea off Coast
A GROUP of dedicated researchers is working to better understand the historically volatile nature of our coastline.
On board the Southern Surveyor, which has taken the team from New South Wales up the Queensland coastline, including working offshore from Noosa and Fraser Island, researchers have identified massive, ancient landslides, which may have caused tsunamis.
Lead researcher, Sydney University Associate Professor in Environmental and Engineering Geology Tom Hubble, said huge undersea landslips, some of which may have created tsunamis dating as far back as five, 10 or even 15 million years ago, had been found.
"It's hard to understand how these slopes ever fail yet the evidence is they can, because there are enormous scars, or scoops, along the continental margin from Bateman's Bay to Fraser Island," Prof Hubble said.
"The big questions for us are how many, how big and how often? And we're making some progress on this.
"We have actually identified 400 landslides over the last four million years that are big enough to have generated a tsunami, most of which would have generated a tsunami with a one to two metre wave height.
"Around 50 to 100 of these could have generated something around five to 10 metres in wave height, which is the size of the tsunamis that came through Indonesia and Japan."
The findings could help Prof Hubble and his crew identify the frequency of events, and potentially help to guide future coastal populations.
"We want to look further now at how the slide went off, the way they move and how they could actually generate a tsunami," he said.
Using techniques such as carbon dating and deep, undersea sonar, Prof Hubble said they hoped to be able to map a timeline of the slides.
"You might get one event every 10,000 years that could throw a wave of more than five metres in height. A wave of more than 20 metres would only occur every 100,000 or even every million years," he said.