Dan Parsons uses the smart boulder to study how sediment moves in underwater avalanches.

Dan Parsons

Dan Parsons

University of Hull

Lottie Dodwell

Lottie Dodwell

Antenna

 

What are underwater avalanches?

current

Image: NOAA Photo Library/Flickr

'Underwater avalanches, or turbidity currents, are huge masses of sediment that surge down vast underwater canyons. The sediment is made up of sand and mud that mixes with water. They can be triggered by landslides, floods or earthquakes. They are the biggest transporters of sand and mud on the planet, but we know surprisingly little about them. '

 

Tell me about the smart boulder...

Larry and BEDs

Image: MBARI

'The smart boulder is an instrument we're using to better understand how sand and mud move across the ocean floor. It's the first time we've been able to track the movement of huge underwater avalanches at great depths in the ocean. '

 

How does it work?

04 – flapjack octopus cropped

Image: MBARI

'It's got a sensor inside like a Nintendo Wii which can track movement. As the smart boulder rolls around, it records data about how it's moving and in what direction so that we know exactly what's happening to it. This way we can monitor the movement of underwater avalanches. '

 

Why do we need to know about movement on the ocean floor?

internet

Image: max pixel

'We rely on underwater infrastructure. Ninety-five per cent of the world's internet cables go under water, as well as phone lines, and oil and gas pipes. If a large underwater avalanche were to hit, it could be catastrophic. We can also use sediment to learn about Earth's history. Sediment movement can tell us how different layers formed and how the shape of the canyon or contours of the sea floor changed over time. '

 

What's the biggest challenge you've faced in your research?

16 – robot arm

Image: MBARI

'Placing smart boulders on the sea floor is hard! We don't drop them from the surface; instead we take them down in a remote-controlled submarine and use robotic arms to position them. It's difficult to make them watertight too. The pressure increases a hundredfold a single kilometre below the surface because of the immense weight of the water. Even a gap the size of a piece of dust would let water in. '

 

Where are smart boulders being used now?

Monterey Bay

Image: tpsdave/Pixabay

'Currently we've got a few in Monterey Canyon, off the coast of California. It's a huge underwater canyon, deeper than the Grand Canyon. We'd like to study other places with different climates too. At the top of my list are glacial areas and offshore in New Zealand, where they experience a lot of earthquakes. '

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