I just put my horse into her turnout from the pasture as I was going into town. She's high-strung anyway and all of a sudden for no reason I could see, she started bucking and kicking just in a panic. All I could do was stand there and go "What the heck is wrong with her now!"
She was going crazy. I'm in southern Oregon. I didn't want to leave her, but had to go. I didn't feel anything but my MIL in the back house felt it shaking
In '94 our dog starting barking wildly and shaking uncontrollably in the early morning. A full 10 minutes later the earthquake struck and nearly toppled the entire house.
One of the structural engineers who examined our house days later said that dogs' sense of smell is so acute they actually smell the gases being released from the earth before the quake hits and they're spooked by the sudden change.
Although our dog also reacts like that to pizza.