I heard them yesterday while working in my office in SE Norman a little after 11am. I'd hear the boom first like a cannon from afar, then maybe just a second or two later a large framed picture that I have on one of my walls would slightly rattle. It kept repeating like this almost like clockwork for several minutes. It didn't feel like any earthquake we've ever had. I did however check the message board to see if anyone updated the earthquake thread. I then went to the USGS site to see if there was any updated activity but saw nothing. I eventually went outside to see if I could find out where it was coming from. It sounded like someone was setting off an explosive blast somewhere off in the distance towards the south. After a few minutes, they stopped altogether.

While I don't know what it was, I certainly don't buy the "frostquake" theory. If you Google it, it appears this phenomenon has been recently happening all across the country at various times and no one seems to have any explanation.