Renewed interest in fracking in the UK will bring more attention to bear on microseisms, the faint earth tremors which make up the planet’s background noise. This all-pervasive vibration is sometimes figuratively called the ‘Earth Hum’, but unlike the many mystery hums around the world, the Earth Hum is much too low-pitched for human ears. While some microseisms are caused by human activity, the vast majority are the result of natural phenomena – though exactly which phenomena is not always known, and some regular signals remain enigmatic.
The most famous of these regular microseism sources was first recorded
