Earthquake or ?

We just had an explosion near our house. Sirens and fire trucks in the distance.
 
Would you believe that I can hear and feel the thumps of the exploding shells here in Trenton? The overcast sky and temperatures are perfect for long range acoustics. At first, I thought it was the the power plant at Duck Island venting steam or blowing out the stacks, but soon came to realize what I was hearing was activity at Fort Dix. The base is about twenty miles away from where I live!
 
Just heard two more of these 'booms' and now there is a continuing low frequency rumble rattling the windows slightly. Started at about 4:07. Inside now but headed out for a walk, maybe the source will be more clear there. I'm thinking they must be some kind of sonic booms.
 
Heard it again about 4:58 while I was outside, it was coming from the Southwest. This time I think there may be a simple explanation... thunder. :D Some dark clouds have appeared and we had a light sprinkle.

thunder.jpg
 
Back in February I checked with friends at the Delaware Geological Survey. Nothing seismic was recorded. There was no ordnance testing at Aberdeen or Wallops Island, the direction that I heard the rumble come from.

That boom was heard in Mays Landing, Vineland, Elmer, Tabernacle, and Mt. Laurel, which is a 26- by 10-mile swath running N/S or S/N. An airplane would have to pass along that trajectory to be heard in each area, yet there was no jet engine sound heard or contrails seen – at least by me. I spent a good amount of time in the outdoors but this sound was a first.

The snow peas (Oregon Giant) planted that day are now a foot tall.
 
March 19........Cape May County Emergency Management says it’s received numerous phone calls regarding “building shaking and trembling” around the Wildwood/Mays Landing area.
North Wildwood Mayor Bill Henfey also says he received two calls, and several calls have been reported in Lower Township as well.
The shaking apparently happened around 3 p.m. on Tuesday and was felt throughout Cape May County all the way up to Egg Harbor Township in Atlantic County.
The USGS says they have a “zero” reading for any seismic activity, and they’ve ruled out an earthquake.
http://philadelphia.cbslocal.com/20...rted-in-cape-may-county-earthquake-ruled-out/