Listen

Everything this station listens for happens between 1 and 15 Hz, one to three octaves below human hearing. So this is not a matter of turning the volume up — the sound has to be moved, and how you move it decides what you actually perceive.

Thirteen band-pass filters run across the live signal, and each one’s loudness drives a single tone. What you hear is a chord whose balance is the shape of the ground’s motion right now — mostly the neighbourhood: traffic on Route 12, wind and thermal drift, the house’s own machinery, and, a few times a week, the sharp arrival of an earthquake.

What you will not hear is the ocean. The microseism — the ceaseless hum of distant surf that larger instruments record hundreds of kilometres inland — lives at 0.07–0.15 Hz. That is not merely quieter than the lowest tone here; it is below the bottom of this whole range, and measured against a Bodega Bay wave buoy it also sits about 100× under this geophone’s noise floor. A 4.5 Hz element is simply deaf to it.

This is a sonification, not a recording, and it is worth knowing exactly how — because the two modes do different things to the pitch, and only one of them compresses.

Compressed squeezes the 3.91 octaves of 1–15 Hz into 2 octaves centred on A3, an octave below concert A. Intervals are therefore warped: a signal at twice the frequency does not arrive an octave higher. That is the price of landing the whole band where an ordinary speaker can reproduce it.

True pitch does not compress at all. Every frequency is multiplied by 16, so 1 Hz becomes 16, 10 becomes 160, and 15 becomes 240. Because ×16 is exactly four octaves, the 3.91 octaves in the ground stay 3.91 octaves in the ear: it is a transposition, the same shape played higher, with nothing warped. The catch is the bottom of it — 16 Hz is below what most speakers can produce, so this mode wants a subwoofer or good headphones.

What survives faithfully in both modes is timing and relative loudness — nothing is sped up, so every swell and onset happens when it happens.

It buffers for a few seconds before starting, then plays for up to a minute. Because playback runs at real speed, that head start is also the whole tolerance for a network hiccup: it never catches back up.