Interesting but I wouldn't be surprised if there turn out to be simple, natural (or man-made) explanations behind it such as with the China Ghost City.

Especially this year, I'm highly reluctant to immediately jump to supernatural/alien explanations. With all the 2012 hysteria that is going to be building up this year, I suspect even the slightest unusual event will be over-hyped for the sake of generating some media attention or internet traffic.

And I'm sure the hoaxing community (with access to increasingly sophisticated video and audio manipulating technology) will also be having a great time this year :)

Having said all that, I'll probably be walking down the street today, have an alien craft land in front me and some six-fingered green ET occupant will come out and slap me around the face for being such a skeptic :)

Here is a link on the Hum sound. This sound has been heard all around the world for years. I remember when the Taos Hum was on Unsolved Mysteries on the television years ago.

I think it is Black Ops if you ask me our government are probably doing a bunch of underground stuff we'll never know about. Maybe testing some kind of energy weapon underground in some giant underground building no one knows of. Those are just speculations of course because Black Ops are top secret we can imagine anything and they are probably doing it with billions and billions of our tax dollars to spend unaccounted for who knows what they have been up to?

Here is a video with one explanation. I realize this video is about NASA in Mississippi, but there are earonautic facilities in other countries.