Forget High-Tech Equipment: Whale Songs Provide Crustal Imaging!

By Jim Brace-Thompson

Geoscientists have spent fortunes sailing about in ships equipped with sonar and air guns, laying out underwater grids of seismic detectors, and deploying fleets of buoys and drone submersibles. These fortunes have all been spent in the effort to understand interfaces at the bottom of the Earth’s oceans. These include interfaces between oceanic sediments, basaltic “basement rocks,” and the gabbroic lower crust beneath the basalt.

Now, it turns out, whales have been monitoring this just fine all along, thank you very much!

Specifically, fin whales. Václav M. Kuna (College of Earth, Ocean, and Atmospheric Sciences, Oregon State University) and John L. Náb?lek (Institute of Geophysics, Czech Republic) published an article in a recent issue of the journal Science in which they note how fin whale calls are detectable over great distances of open ocean and how such calls have been recorded by ocean-bottom seismic stations. Not only have the songs been captured and recorded, they apparently “contain signals reflected and refracted from crustal interfaces beneath the stations.”

Kuna and Náb?lek are hopeful that such powerful but decidedly low-tech fin whale vocalizations might be usefully employed by geoscientists to complement their expensive high-tech gizmos. Who says you need to spend a fortune? That is, until whale lawyers and whale accountants get wind of all this!