No. 68: Mar-Apr 1990
In our catalog volume Earthquakes, Tides, Unidentified Sounds, we recorded many curious natural sounds, including the "desert hum," the "Yellowstone Whispers," and, pertinent to the present discussion, a throbbing, humming sound afflicting some, but not all, residents of the British Isles. Percipients describe the hum as like a "diesel truck with its engine idling." The electronic environment of Britain has been blamed for the hum: transformers, high-voltage transmission lines, and pulsed radars are all candidate hum-makers. For, it has been discovered, some people somehow convert pulses of electromagnetic energy into a perception of sound. This facet of the British "hum problem" was covered on p.000, where the infamous Soviet "Woodpecker Radar" is mentioned specifically. But are electromagnetic pulses really to blame?
The British hum has become a nuisance - to those who can hear it - during the past 20 years. This is just the period during which British Gas has been installing a nationwide gas-distribution system, which employs powerful turbines to pump natural gas through underground pipelines. H. Witherington, an unhappy hum-hearer, has for years driven around Britain at night when things are quieter, plotting places where the hum can be heard. He has found that the sound follows the gas pipelines and extends for several kilometers on each side. Houses, he finds, tend to amplify the sound, because closed rooms sometimes create resonant conditions.
(Fox, Barry; "Low-Frequency 'Hum' May Permeate the Environment," New Scientist, p. 27, December 9, 1989.)
Reference. Ordering information for our catalog (mentioned above): Earthquakes, Tides may be found here.