I live in a fault zone in BC and we actually picked out the location of our housing on the basis of the earthquake charts. I stayed in the same area in my rental house. Hard pan on bedrock here....

I was in an earthquake upgraded building at the top of a mountain during the Nisqually quake and it felt like an elephant on a pogo stick went by behind my desk; hubs and a visiting girlfriend didn't even notice, less than 5 miles away, and they were sitting under a chandelier, so they likely would have. Tremors are weird.

The idea that it was directly under your house is rather charming, in a mildly scary way.