20 points answer
tell me a dependent variable of how do different foundations stand up to earthquakes?

Another way to test your question is to build your own miniature buildings. Depending on how in-depth you go, building could get a little pricey, but if you keep it basic there shouldn't be a problem. Decide on a certain number of foundations to test [maybe 3 or so] and try simulating an earthquake. 
Hope this helps!