In 2003 Australian geological researchers suggested prehistoric tsunamis over the last 10,000 years were much larger than those recorded since European settlement, including findings of surges up to 20 metres in height affecting a 2500km stretch of the West Australian coastline.

But archaeologists from The Australian National University have questioned these claims, saying that some of the key evidence for ‘mega-tsunamis’ can be explained by human activity.

“Our field work would suggest that the shell and coral deposits found high on headlands in WA or further inland are evidence of Aboriginal occupation of the area, and not deposits of mega-tsunamis or other major inundations,” argues researcher Dr Tony Barham from ANU. He and his colleagues Dr Sue O’Connor and Dr Stewart Fallon also found that archaeological deposits in the area have not been disturbed by major inundation for the last 1000 years, undermining the previous theory that giant waves had flooded the area once every 400 to 500 years.

“These earlier theories about mega-tsunamis and their frequency have been quite influential in WA for the development of emergency service plans – but our research would suggest that they are not supported by the archaeological evidence.

“This is a great example of why solid archaeological research should be taken into account in the planning processes for future emergencies. Archaeology is a vital discipline for understanding the environmental and climate-change risks we face in Australia, as it shows how the continents’ earlier inhabitants dealt with sudden and long-term changes to their environment.”

Dr Barham is presenting the findings at the Archaeological Science Conference at ANU, which will launch the University’s new Masters in Archaeological Science program. Other presenters at the conference will look at how early agriculture was sustained in drying landscapes, and how homo floresiensis or ‘hobbits’ fit into the story of human evolution.

Source: Australian National University