The Earth Always Hums: Infragravity waves and current-generated noise and the microseisms (acceleration x6000)

Left: The spectrogram of the infragravity waves and current-generated noise (the time-variable broad bright spots on the left) and the ocean microseisms (the continuous band at higher frequencies, on the right of the spectrogram). The spectrogram shows the signal strength—or how loud it is—over time and at different frequencies. Labels and scales appear periodically. One of the horizontal scales at bottom left shows the original period of the signal in seconds. This signal is inaudible to the human ear. The recording has been accelerated by a factor of 6000, bringing all the signals into the audible range. The frequency scale (bottom left) marks the frequency (Hz) of the transformed signal that we hear. Right: the 3D visualization of the sound.

This stereo track is a rendering of the 3 components of the motion of the seafloor at a 3.9 km depth, southwest of Ireland. The seismograms were recorded on 1-19 April, 2020, by the ocean-bottom seismic station Brian of the SEA-SEIS network.