Dogs in particular can smell the changes in the earth before they happen, their noses actually pick up the changed scent caused by the movement of the plates beneath the earth, and they also hear the lower pitched noises from the ground movement long before we hear the freight train noise common to large quakes. Cats will become completely crazy right before a big quake, sometimes doing strange things like climbing the drapes or trying to go up a chimminey in a fireplace!
Watch the dog for signs that he scents something!8o