Some of the VLF recordings I've heard are quite soothing.
Just nature doing it's thing in the radio spectrum.
My receiver came with two tapes of recordings so I guess in
some way it's published.
http://www.triax.com/vlfradio/
And, although not natural as such, the Connet Project.
Sit down in a dark room, listen to this and my brain
starts re-writing The 3rd Man.
http://www.ibmpcug.co.uk/~irdial/coneline.htm
There is also an Australian who likes to record
the vibrations of 1/2 a mile of telephone wire.
Can't remember his name or the label.
Apparently animals scratching themselves on the poles
makes quite good bass.
Later............
Steve.
NP: People makeing noises in the kitchen.