True to its name, the Great Barrier Reef is providing an effective barrier against landslide-induced tsunamis, a new study finds.

According to researchers at the University of Sydney, the world-famous reef does the Australian coastal communities a great service because of its ability to absorb some of potential wave energy caused by tsunamis.

Their research shows that a shallow underwater landslide reaching seven kilometre-wide occurred around 20,000 years ago off the edge of the continental shelf. It caused a tsunami two to three metres high on the paleo-coastline lying between Airlie Beach and Townsville.

The tsunami could have impacted Aborigines living at the time along estuaries and on islands off the paleo-coastline, which has since receded under the rising sea levels that followed the last ice age.

What has developed into the Great Barrier Reef was not always a barrier reef, according to the researchers. Instead, it was once a fringing reef and did not offer the same protective quality. This is because the coast at this time was much closer to the source of the tsunamis, says the study’s lead author, Associate Professor Jody Webster from the Geocoastal Research Group at the University of Sydney.

For the study, Dr Jon Hill from the University of York created visual simulations of the tsunami impact at today’s sea level, as well as at a depth of -70m, where the paleo-coastline was before it receded to its current position and was replaced at the shelf edge by the formation of the Great Barrier Reef.

The research team has named the submarine landslide the Viper Slide because of its location adjacent to Viper Reef.

“The discovery of the Viper Slide is the first solid evidence that submarine landslides existed on the Great Barrier Reef,” says Dr Robin Beaman from James Cook University and a member of the expedition that mapped the slide.

While similar landslides under the sea could occur without our knowledge, there is a relatively low chance that they would cause a tsunami of up to three metres or more, according to Webster. However, should something like it happen today, the Great Barrier Reef will serve as protection, Webster adds.

Just how much energy would be absorbed and what the extent of damage could be done by rising sea levels and tsunamis or king tides is the subject of future research.

In 2012, researchers mapping the sea floor near the Great Barrier Reef revealed that they have found a giant slab of collapsing sea floor that could trigger a tsunami in the future. In a report published by ABC, marine geologists at James Cook University said it is only a matter of time before the slab, known as the Noggin Block, collapses and cause a catastrophic tsunami. They claimed that the tsunami would be about 70 kilometres offshore, and would impact the North Queensland area.


Source: YouTube/The University of Sydney

Contact the writer at feedback@ibtimes.com.au or tell us what you think below.

RELATED STORIES