naturalplastic wrote:
Yeah. I was wondering if you werent hearing rocks under stress in the crust beneath you. If I am not mistaken I think that you said that you live in western Pennsylvania (were the mountains are). Maybe you all are about to get a local earthquake there. Keep us posted. We don't have as much seismic activity as they have in California, but we here in the east, near the Appalachians, do get some seismic activity. There was a major-minor quake in Virginia a few years ago that we all felt here in the Washington suburbs- enough to scare me and all of my neighbors out on to the street.
When I hear/feel the low-pitched vibrations, I also suspect the source may be some underground micro-collapses.
My city is on quicksands, they really move - not like in the movies but new buildings cracking a few years after construction happen all the time, both my past workplaces did.
And they are currently building a tunnel just a few km from here.
The hum is really hard to bear sometimes, my husband hears it too - his hearing is extremely sensitive - but I don't expect any extraordinary source of it with so many possible ordinary sources available.