The Earth’s ‘hum’ is driven by ocean waves over the continental shelves

The Earth is regularly emitting a low frequency 'hum' equivalent to the energy released from a magnitude 5.75 earthquake. Since its discovery the source of this 'noise' has been projected to be some combination of the interactions between the atmosphere, the oceans and solid Earth, but exactly what produces it has remained something of a mystery. Now Spahr Webb presents calculations that suggest that seismic energy generated by the interaction of ocean waves with the shallow continental shelves, rather than atmospheric turbulence, is the probable source of the hum.