Earthquake sensors deep in the ocean are capable of picking up the vibrations that fin whales create when they sing, allowing scientists to be able to track them easier.

The devices are called seafloor seismometers, and they are considered an inexpensive way of finding out more about fin whales without displacing them too harshly.

Three papers published in the Journal of the Acoustical Society of America are the first to piece together the sounds that the whales make with fine-scale swimming behaviors. This means that scientists will be able to study the animal’s movements and communications in a much easier, non-invasive manner.

The research was partly inspired by the danger ships pose to fin whales, nicknamed the “greyhounds of the sea”. The idea is that if scientists understand the whales’ migration patterns better, they can provide information so ships avoid them.

But fin whales are also one of the least understood animals in general on the planet.

University of Washington doctoral student Dax Soul discovered some contradicting migration patterns for fin whales in 2003. During his study, he found that three groups of whales were traveling south for the winter, but that one group of males would head north in the fall.

“One idea is that these are juvenile males that don’t have any reason to head south for the breeding season,” Soule said. “We can’t say for sure because so little is known about fin whales. To give you an idea, people don’t even know how or why they make their sound.”

Unlike other whales, fin whales sort of chirp, rather than sing. This made it easier for the research.

Another doctoral student at the University of Washington, Michelle Weirathmueller, continued the study, finding that the whales’ calls consistently hit around 190 decibels. When converted to air, it is 130, which is roughly the volume of a jet engine.

“We’d like to know where the fin whales are at any given time and how their presence might be linked to food availability, ocean conditions and seafloor geology,” Weirathmueller said.

“This is an incredibly rich dataset that can start to pull together the information we need to link the fin whales with their deep-ocean environments.”

Fin whales are the second largest living animal on the planet, second only to blue whales.