Because there are fewer faults in the Eastern half of the country, for the same size earthquake the energy travels MUCH farther than in California; it’s like hitting a bar of steel at one end and feeling the vibration at the other end, instead of hitting a box of gravel at one end and feeling nothing at the other end.
So that drives a lot of the Californian smugness; they’re not aware that people are feeling the same shaking they do from the same size earthquake, but in some places upwards of ten times further away.
Didn’t know that! Thanks for the insight.