Well, I'd say the class would be good for getting back in shape in general. Especially a beginners class, where you can get stuff wrong and take all the breaks you need. But, yeah, the lovely laziness has to be given up first.

Seriously! I mean, everywhere gets microquakes, but not stuff you feel! And DC is actually in the middle of a plate, so yeah, they are extremely rare. I've heard stand in a doorframe, or get under a heavy piece of furniture so stuff doesn't fall on you (though if the floor falls, you're pretty much screwed anyway).