As we watched the news of today's earthquake develop, we marveled at how far and wide the reports were coming of people having felt the motion. Boston? Really? Detroit? Chicago? Really?
This animation doesn't explain why the quake could be felt so far away, but it does show the far reaching wave effect across the country. The video comes from this page from the Incorporated Research Institutions for Seismology. Each little circle represents a seismic station location. The color is showing the station moving up (blue) or down (red). They offer this brief explanation of the visualization here, but it behooves you to take the time with this longer tutorial. It'll give you that good "I'm smarter than I used to be" feeling.
I just finished watching the videos here about how earthquake waves behave differently depending on the type of bedrock they're passing through. I wonder if this explains the lingering motion in the Gulf in the video above.
Anyway, just remember to come back to your TV by 9 pm.