Correct... The ground is harder here in the northeast, compared to the west coast. The harder the ground, the further spread out the tremors will be felt.
In the west, the ground is soft. That is why people would not shake a stick at a 4.8 Richter scale earthquake, because they don't feel it as much or as far spread out from the epicenter... That and, earthquakes that are noticable are rare here in the northeast. The last noticeable one here in the northeast was in 2011.

