Whats That Sound?

So I was just looking back at all my blogs I have written so far and they kind of suck.
Anyway I got to thinking about the town that keeps hearing booms underground. I dont know alot about it just what my husband has told me and that is that the town keeps hearing these terrible booms coming from underground and they do not know what it was. At first, they said it was tiny earthquakes and now they are saying it is not. Anyhow that is all I know about it. Now what I want to blog about is what could it be if it is not an earthquake. I have a couple theories.

1. The government is preparing for the apocalypse by making an underground city just for the military and government officials ( the citizens of America get screwed out of this deal ).
2. Transformers are real....that would be pretty cool. They were aliens that were buried underground thousands of years ago.
3. There are giant worms that are running out of food and are getting closer to the earths crust in search for food. Imagine the worms from Beetle Juice or Tremors.
4. The everlasting search for oil is messing with the earth and some kind of diabolical movement is going on under there.

O.K. the last one was grasping at straws, but the other three just might could happen. Hopefully, the town lives to see another day and none of the above is the cause for the unexplained booms going on.