“An enigmatic humming sound made by the Earth may be caused by the planet’s stormy seas, suggests a new analysis.
Japanese seismologists first described the Earth’s humming signal in 1998. It is a deep, low-frequency rumble that is present in the ground even when there are no earthquakes happening. Dubbed the “Earth’s hum”, the signal had gone unnoticed in previous studies because it looked like noise in the data.”
More here from New Scientist.