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Environment

Turns Out the Great Barrier Reef Is Protecting Australia From Tsunamis

Over the last half-century, Australia has been pretty garbage to the Reef. But it turns out it's been a better pal to us, than we've been to it.
November 26, 2015, 1:35am

Over the last half-century, Australia has been pretty garbage to the Great Barrier Reef. If we're not dumping dredge waste on it, we're poisoning the thing with pesticide run-off. But while we've failed to protect one of our most celebrated natural features, it turns out the reef's had our back this whole time. Aside from providing a setting for the 2006 Jojo vehicle Aquamarine, the 2,300 kilometres long reef has also been protecting Australia's coast from tsunamis. Barrier by name, barrier by nature.

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This week research from the University of Sydney's Geocoastal Research Group revealed that the Great Barrier Reef serves as a sort of fortification to landslide-induced tsunamis along Australia's northeast coast. Called "submarine landslides", these disturbances are caused by collapsing areas of sea floor that can produce destructive waves. The reef currently buffers us from absorbing all that energy. The Group's research showed that between 20,000 and 14,000 years ago, a seven kilometre wide landslide occurred creating waves up to three meters high. Although small compared to the 30 to 40 meter waves seen during the 2004 Indian Ocean and 2011 Japan tsunamis, this disturbance would have impacted indigenous communities along the coastline between what is now Airlie Beach and Townsville. During this time, the world's largest reef was just a baby fringing reef, more similar to Ningaloo Reef on Western Australia's mid north coast. These days, thanks to the reef and the layout of our modern coastline, our risk of large waves caused by landslide is low, but not impossible. In 2012 researchers mapping the sea floor in the area discovered a large slab of collapsing sea floor called the Noggin Block that they theorised could trigger a tsunami in the future. If the block did giveaway, it's possible it would cause a tsunami 70 kilometres offshore that would impact North Queensland. In relation to the possibility of a repeat performance of the waves that occurred 20 thousand years ago, the Geocoastal Research Group is investigating whether or not current reef degradation could impact its ability to act as a tsunami barrier. While the news is pretty unsettling, it's not like we need another reason to lose sleep over the reef. Remember the reef is roughly the size of Germany, so damaging it does more than threaten the multi billion tourist industry it supports. This massive stretch of national park also homes 1,500 species of fish, 134 species of sharks and rays, six out of seven of the planet's threatened marine turtles, and 30 species of threatened marine mammals—including dugongs, the ocean's awkward best friend. But hey, if that's not enough to pay attention, maybe the knowledge the reef is keeping our shoes from getting wet will do it.

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Note the considerable lack of massive waves. Image via