Earthquake in Arizona?

As I was writing the last post, I had the sensation that I was moving. Claire was sitting on my lap, and the thought crossed my mind that I was dizzy or something. I looked up and noticed the chandelier above me swaying back and forth. I looked into the kitchen and noticed the light fixture above the kitchen table swinging back and forth. I knew it wasn't me that was dizzy... it was an earthquake. I ran to the stairs and yelled to Rob in the basement. He felt it too. We called the neighbors- they felt it too and even noticed the water sloshing out of their pool. So what was it? Arizona isn't immune to seismic activity, but we've never felt it at our home. According to the U.S. Geological Survey, Baja California, Mexico experienced a 7.2 magnitude quake at approximately 3:40pm and then a 4.5 magnitude 20 minutes later. Southern California felt it and we did too. Wild!