Since we live in an oilfield they have to so all kinds of testing to make sure the ground is stable. So they set little machines all over out in different fields and by our house. Then later they brought out these big machines that put vibrations in the ground. I was outside when they were shaking the ground, it felt so weird! I can't imagine being in an earthquake where the ground is really moving under you. I know this doesn't compare, but it was strange feeling.