In April we talked about the awesomely primal humming that Mother Earth has been mysteriously emitting. If you remember, these hums have the loudness of 6.0 earthquakes and were said to be generated by the “interaction between the ocean, the atmosphere, and seafloor, between the Northern Pacific and the Southern ocean.”

Researchers have been trying to put their heads together and find out what the cause of this hum is for over a decade. The source of the hum has now been discovered to be sea waves crashing against one another—specifically in the Pacific Coastal region of North America.

The two waves that are creating the sound are of similar frequencies; however, they’re traveling in opposite directions, causing them to collide. As they hit, a unique pressure wave is created, which races down to the ocean floor, slams into rocks, and generates a vibration that causes the hum.

It is not unique, however, to the region; in fact, as it’s happening in places all over the planet at different times, it gives the impression of a non-stop hum. The data was collected by using a US Array EarthScope, an instrument that made scientists able to find not only the North American hum but also one in Europe. The humming comes from mostly coastal regions rather than deep sea areas.

While the mystery may be solved, it doesn’t put an end to the idea that many scientists share—that the earth itself is the largest living organism. OK, so the hum doesn’t seem to have a truly vocal source—just because something isn’t humming doesn’t mean it’s not alive, right?