re: #72 austin_blue

East Coast quakes (actually most quakes east of the Rockies) tend to have very large shake zones compared to California. Geologists think this has to do with the fracturing in CA compared to the rest of the US - and the fracturing manages to dissipate the energy.

But this has to be the video of the day: via Phil Plait:

Youtube Video

It shows the quake wave move across the US according to very sensitive sensor arrays.