‘For every little red dot on the map, someone has reported hearing a low-frequency hum whose source they’ve been absolutely unable to identify.It’s not a new phenomenon, either. When Britain’s Sunday Mirror tabloid published an article about it called “Have You Heard the Hum?” in 1977, 800 people contacted the paper to say they had. There are accounts of what could be the hum dating as far back as 1828 when travelers to the Pyrenees heard a ”dull, low, moaning, aeolian sound” they couldn’t identify. And as recently as early April 2016, residents of Plymouth near the south shore of England were experiencing the return of an unexplained hum they’d first heard a year earlier…
The man behind the World Hum Map is Dr. Glen MacPherson, a former lecturer at the University of British Columbia. His map is a crowd-sourced effort to start figuring out, in some scientific way, what on earth—or above it?—causes the Hum. McPherson himself suspects the Hum may be a product of VLF (Very Low-Frequency) radio transmissions.
- Patrick Kempf
Now Fabrice Ardhuin, a senior researcher at Centre National de la Recherche Scientifique in France announced in Geophysical Research Letters, a journal of the American Geophysical Union, that he’s figured out what produces the Hum: Pressure from waves on the seafloor are causing the Earth to oscillate and produce low-frequency sounds for 13 to 300 seconds. These microseismic waves can be picked up by seismic instruments and by the small number of people sensitive to these low frequencies…’
Source: Big Think