Seismologists studying earthquake activity off the US coast recorded fin whale songs, which they found can be used to tell the thickness and makeup of Earth’s crust
Source:
https://www.newscientist.com/article/2267630-sound-waves-from-fin-whale-songs-could-help-us-study-earths-crust/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home