BAKER, NOTABLE
Mysterious booms in Pennsylvania.
Article is phrased interestingly. Mentions 'tunnels or space junk' as the posssible cause within the first few lines. Mentions that they aren't earthquakes and has a named ex-military source confirm they're not gunshots - and carefully avoid saying they're not explosions.
This feels like comms to me.
Isn't PA coal mining country? Lots of potential for underground fuckery.