Australia's unexpected secret weapon against tsunamis
Saturday, November 28, 2015, 12:40 PM - Some countries have to shell out billions of dollars in tsunami defense and mitigation. Australia apparently just has to look to its most famous natural feature.
The Great Barrier Reef, off the coast of the Australian state of Queensland, plays a critical role against undersea landslides and tsunamis, according to researchers at Sydney University and the University of York.
The researchers found that a seven-kilometre-long undersea landslide occurred in the area at least 20,000 years ago, triggering a tsunami up to three metres high that would have had a major impact on Aboriginal communities.
"There is a relatively low chance that a similar submarine landslide with the potential to cause a tsunami of up to three metres or more would happen today," Sydney University professor Jody Webster said. "However, if one did occur, our findings suggest that the Great Barrier Reef is doing us a great service because of its ability to absorb some of that potential wave energy."
Back then, the reef was less of a barrier and more of a fringing reef, and sea levels were lower, meaning the coastline was much closer to the source of tsunamis.
With knowledge of that prehistoric tsunami, the researchers could extrapolate how the Great Barrier Reef could mitigate the effects of future tsunamis, running simulations based on historical data and current sea and reef levels.
However, the 2,300-kilometre-long reef is threatened by ocean acidification, pollution and global warming, raising questions about its ability to serve as a tsunami barrier.
"Our future work will try to answer these questions," Webster told the Sydney Morning Herald said. "In particular, we'd like to know how much energy would be absorbed and how much damage could be done by rising sea levels and tsunamis or king tides."
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