 Although earthquakes in the central and eastern U.S. are tens of times less frequent than in the western U.S. , they are typically felt over a much broader region . East of the Rocky Mountains , an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast . Western rock is relatively young , therefore it absorbs much of the shaking caused by earthquakes . Hence , western earthquakes result in intense shaking close to the epicenter , but fade more quickly the further the earthquakes travel . In the eastern United States , the rock is much older , and earthquake energy can therefore spread further and have a greater impact . A magnitude 5 @.@ 5 eastern U.S. earthquake can usually be felt as far as 300 mi ( 483 km ) from its origin , and sometimes causes damage as far away as 25 mi ( 40 km ) . The relatively shallow depth of this earthquake also contributed to its widespread effects . 
