concrete theory

[terracore]

1) I've never heard of crushed rock having anything to do with earthquakes. I thought it was for leveling, and to keep the soil from eroding under the concrete, or to facilitate drainage.

2) I've heard of using 3" for backyard sheds, but never anything as small as 2" except for pavers etc.

Also, I have very little experience with concrete so can only regurgitate pedantic knowledge.