Could ocean waves be making planet Earth hum?

Beneath the everyday noise of human activity, the planet Earth emits a constant, ultra-low-frequency vibration, a phenomenon known as Earth's hum. First detected in the 1960s, the origin of this subtle planetary resonance has remained a scientific mystery for decades. However, emerging evidence strongly suggests that the world's oceans, in their ceaseless motion, are the source of this global hum.

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It's a seismic signal, which is a very small vibration that gets picked up by seismometers and it seems to be very regular.

Chief scientist at the Seismology Research Centre, Adam Pascale, explains that the prevailing scientific theory attributes the hum to the immense pressure exerted by ocean swells, particularly those originating in the Southern Ocean. These swells generate tiny vibrations that travel through the entire Earth. This process involves the interaction of wave pressure with the fluid within the Earth's crust, which then amplifies these interactions into microseismic signals.

Pascale noted that this isn't the first time scientists have encountered unusual planetary vibrations. He recalled a mysterious, regular pulse detected in 2023, which was eventually identified as a massive landslide in a Greenland fjord. This event created a colossal wave that sloshed back and forth, demonstrating how geological and oceanic disturbances can create detectable seismic signals.

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In the Gulf of Guinea, just off the west coast of Africa, those swells generate tiny vibrations that travel through the entire Earth.

Scientists like Rohan Byrne from the University of Melbourne's Earthquake Research Group are using seismometers, traditionally employed to monitor tectonic plate shifts, to listen to the oceans. Byrne's work, which involved speeding up recordings from seismic stations worldwide, inadvertently captured both the Earth's hum and a distant earthquake simultaneously. This highlights the complex seismic activity constantly occurring on and within our planet, and underscores how much remains to be learned about Earth's intricate workings.

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It highlights how much we still have to learn about how the Earth works.