Originally Posted by
Taylob
First off, this sound has nothing to do with your house and it is refered to as "The Hum."
I live in San Clemente Ca and my dad hears "The Hum" every night when it's really quiet... Really strange. I've looked into it and found that it actually made be caused by the earth itself. Check out this page about this phenomenon and Google "The Hum."
http://www.mydoubleglazingblog.com/double-glazing/the-hum-sounds-from-the-ground-mystery-or-mischief/
It talks about what you are experiencing exactly. People seem to feel this noise. Kinda creepy actually.
Hope this helps.