Seismographs react hundreds of miles away, and are a lot more sensitive than the human ear at 40 miles.
Forty miles for a blast to be audible is amazing.
Did everyone leave the thread?? I'm refreshing and it seems to be stalled.
My dad was living in Houston when the explosion happened in Texas City. His house was roughly 35-40 miles from the Texas City docks and he still remembers hearing the explosion and feeling the ground shake.
As a side note, the Texas City explosion had a yield in the low kiloton range and was comparable with some tactic nuclear weapons.
I've seen and heard Dragonfly's in Guatemala (El Quiche 1982??) dropping ordnance on indig guerrillas from at least that far away between mountain valleys...and A-37s are not exactly rolling thunder like a B-52 ...not meaning to quibble...maybe it's the terrain