I was at the location indicated with the red pointer yesterday. We were outside in the parking lot configuring a new GPS when there was this incredibly loud and deep-feeling explosion. It was like nothing I ever felt or heard before. I must have looked a little concerned, but the guy I was with just waved it off and said something like "Oh, we hear that three or four times a day. There is a quarry just around the corner."

How cool! I have always wanted to hear and feel what a big explosion is like, and now I know. The quarry is to the southeast of the red pointer about half a mile.