Has anyone figured out the source of the BOOMS yet?

[Chris Martin]

Somewhat frequently, although intermittently, many of us hear a booming sound in southern Wake county and northern Johnston county. I've heard them in Sampson county as well, but there I can't tell if the noise is from the same source. 

Over the past month, I've heard them in Holly Springs, Fuquay, Willow Spring, and Lillington. To me, it seems like they are originating in Fuquay somewhere. My guess is it's construction activity (explosives) since I can't pinpoint anything else. 

Any ideas? When you hear them, you think... 'What the h#%%! was that?' as in a train wreck or something.