Quote Originally Posted by Slow Worm View Post
Another writer suggests VLF from TACAMO airbourne tranmitters could be the cause: http://www.scientificexploration.org...8_4_deming.pdf However there is little evidence that people can directly perceive VLF or any other radio frequencies.

Assuming the phenomenon really is external and accoustic, my pet theory is that it originates in the oceans, where there is a mass of millions of tons of water in motion, with the resulting energy transmitted to the ground (sea bed and/or shore) possibly causing vibrations which due to geological conditions may be amplified and detectable at the surface at considerable distances inland

SW

"The new study combines both of these ideas into one model that accounts for these microseismic signals. 'I think our result is an important step in the transformation of mysterious noise into an understood signal,' lead study author Fabrice Ardhuin, an oceanographer at the French Research Institute for Exploitation of the Sea, told Live Science.

Using computer models of the ocean, winds and seafloor, the scientists found that colliding ocean waves could generate seismic waves that take 13 seconds or less to complete one ripple. When it came to slower waves, they found that ocean waves moving over the seafloor could generate seismic waves with a frequency of 13 to 300 seconds. Most of the mystery hum comes from these longer waves."

https://www.livescience.com/50473-ea...explained.html