Also, earthquakes on the east coast travel further, and are more likely to damage structures than earthquakes of the same magnitude on the west coast[0]. That's due to underlying geological differences.

The magnitude is one immediately-available measure of the strength of an earthquake, but it's not the only measurement that's relevant to determining the size or impact of an earthquake. Depth, duration, location - there are many other measurable (and also immeasurable) factors which parameterize a seismic event.

[0] https://www.usgs.gov/news/featured-story/east-vs-west-coast-...