New research has suggested that earlier theories about mega-tsunamis hitting the Australian coast in the past do not hold any truth to them.
Earlier, boulders atop high cliffs on the South Coast and other geological evidence had convinced some scientists that mega-tsunamis inundated the coast during the past 10,000 years, most recently 500 years ago.
But the findings of two different studies, on Aboriginal sites and sediments in coastal lakes, challenge this theory.
"The archaeological evidence we've examined doesn't support a mega-tsunami hypothesis," said Val Attenbrow of the Australian Museum.
For their study, Dr Attenbrow and a Canadian researcher, Ian Hutchinson, studied Aboriginal shell middens between the Central Coast down to the Victorian border. They checked the radiocarbon dates of the sites for any gaps in occupation when waves might have driven people inland.
"The analysis showed no evidence of abandonment of coastal camps by Aboriginal people in the 15th century," said Professor Hutchinson of Simon Fraser University.
An analysis of the seafood people ate also did not fit with the suggestion that a mega-tsunami had destroyed shellfish beds.
Though the development of line fishing has also been proposed as evidence for a mega-tsunami by the leading proponent, Ted Bryant, of the University of Wollongong, the archaeological evidence showed this occurred about 900 years ago.
Also, according to Amy Prendergast, a Geoscience Australia researcher, when she had made a preliminary study of cores taken from lagoons between Sydney and Ulladulla, she did not find any sediment associated with massive inundations.