Whale song shakes up earthquake research
Scientists harness fin whale calls to explore the geological structure of the ocean floor.
If any animals could be described as ‘seismic’, it is surely the baleen whales. These largest of creatures are also the source of the loudest and deepest biological sounds in the oceans. It’s fitting, then, that their rumblings are now being investigated as tools for the study of submarine earthquakes.
“I stumbled across this by accident,” says Václav Kuna, a researcher at Oregon State University. “I’m a seismologist, so I don’t have a clue about whales.”
Kuna was analysing recordings of seismic activity from arrays of microphones on the seabed at the Blanco fault off the coast of Oregon in the Pacific, when he came across some mysterious signals that turned out to be the calls of fin whales, a species of baleen whale.
Painstaking analysis of the echoes of the calls allowed him to glean information about the geological structure of the seabed, in much the same way that bats use sound to map their surroundings.
“We could use these calls to help understand the first few hundred metres of the Earth’s crust, which is important for tracking earthquakes very precisely,” he says, adding that the information might also be useful to climatologists and geologists looking to measure the depth of ocean sediments to work out how much carbon they store.
Mark Jessopp, a whale biologist at University College Cork, who was not involved with the project, describes the work as “a great demonstration of some of the more unexpected results that can come from studies looking at something completely different”.
There is the tantalising possibility that using whale calls in this way could reduce reliance on the powerful and noisy air-guns used by the oil industry to map the structure of the Earth’s crust.
Jessopp is sceptical: “Air-gun noise penetrates deeper and produces higher resolution information on the structure of the seabed that industry needs, so I can’t see [them] switching soon.”
Kuna largely agrees, but says that “it is a step in the right direction towards thinking about how much noise pollution we add to the oceans”.
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Science: bit.ly/3uHiXKA