The Hum of the Earth
Even on days without earthquakes, the whole planet rings very faintly, like a bell. Japanese scientists found it in 1998.
What was reported
After a large earthquake, the whole Earth vibrates for days, ringing at very low frequencies like a struck bell. Scientists long assumed that between earthquakes, the planet fell silent.
In 1998, Japanese research groups analysing sensitive seismometer records found that the Earth never stops ringing: a constant, faint vibration, far too low for humans to hear, continues even on the quietest days.
Explanations offered
Scientists now think the 'hum' is driven mainly by ocean waves, especially long waves pressing on the sea floor along coasts and continental shelves, with some contribution from the atmosphere. Its seasonal changes follow the stormy seasons in each hemisphere.
- When
- Discovered in 1998
- Where
- Japan, where it was first detected
- Witnesses
- Seismometers worldwide
- Status
- Mostly explained
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