The Richter scale can be confusing because it is logarithmic and not linear, and most people (me!) think in linear terms. So a 6.3 earthquake releases something like 43 kilotons (of TNT) of energy while the 5.8 (first report)Virgina earthquake released something like 7.6 kilotons. A big difference. Thus, the Christchurch quake released something like five and a half times more energy than the Virginia quake. I'm always confused by log scales, so I had to look it up here:
http://en.wikipedia.org/wiki/Richter_magnitude_scale

Of course, there are thousands of variables of how much damage is done in any particular place. Old saying: In real estate, location is everything. E.G. some buildings in Baltimore MD, 45 miles north of DC had their facades (Brick) fall off, in all or in part, while here in Annapolis, there are no reports of such damage.

There is one report that the Washington Monument is "leaning".