Whales are famous for their deep, loud calls that travel for miles in the ocean. In fact, the bellows of fin whales can be heard from 600 miles away. Researchers are now looking to those whale calls to help them map out elusive sections of the deep seafloor.
Seafloor imaging is used to study seismology and seafloor carbon storage capacity, but getting a clear picture of the deep sea is not always easy. Traditionally, researchers have used large air guns to send powerful soundwaves down into the sea and measure echo timing to map out the underwater world. These guns are not only costly, but they also disrupt marine species’ communication signals. This is why seismologists have turned to the sea’s natural signalers to garner the same data with less invasive techniques.
Researchers from Oregon State University were studying the Blanco transform fault off the Oregon Coast when they started noticing unusual readings in their data. These turned out to be fin whale calls, which is how they got the idea to pinpoint the location of the whales and measure the time it took for their calls to reach their sensors. Each whale creates two sets of calls: the one coming from the whale itself and the one that is in fact an echo emanating off the seafloor 2.5 kilometers below.
Fin whales are especially good for seismology because they call out in loud, one-second pulses which are easy to track. They are also a species found virtually everywhere in the world, with the exception of portions of the Arctic, so their calls could be used for research around the globe.
The whale calls do have some limitations. They don’t quite have the frequency range of machine-generated calls, so they are only highly effective on flat sections of the seafloor, but they do offer great supporting data and can substitute at least some of the disruptive artificial sounds.