Survey detour discovers underwater mountain

31 May 2006

An underwater mountain rising 300m from the sea floor, and 5km in length has been discovered using a swath mapper onboard the National Facility Research Vessel, the Southern Surveyor. The discovery came about unexpectedly during a voyage to investigate continental shelf processes between Cape Leeuwin and the Great Australian Bight.

The underwater mountain, named Mt Gabi by the Chief Scientist of the expedition, Professor Charitha Pattiaratchi from the University of Western Australia, is located 50kms south of Augusta on the Western Australian coast.

Sonar image of recently discovered Mount Gabi, offshore WA.

The unexpected find came about in April when Cameron Buchanan, a Multibeam Sonar Specialist from Geoscience Australia, took advantage of a last minute detour to the planned schedule when the vessel had to increase its fresh water supply.

"I was asked to design a 24 hour swath survey as we had to cruise around for a period to generate more fresh water, so the find was fortuitous," said Cameron.

"Some mapping had been conducted in the area by French researchers, but I knew that we were very close to an area where some data had not been collected. So I was able to design a survey that covered the head of the Leeuwin Canyon, an unknown area."

Although Mt Gabi is not an unusual feature on the seabed in this region, exercises like this demonstrate that there are large areas of the sea floor that remain uncharted and scientists like Cameron Buchanan will play a valuable role completing this enormous task.

Geoscience Australia provides technical support to operate the specialised swath mapping equipment onboard the Southern Surveyor.

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