Many years ago.
I was working as a Journeyman Electrician, Industrial, Petrochem construction. Pulled a slip for a job in California, a week after I got there we were up in structure, about 200 feet or so. Please note, not a building, an open framework with expanded metal flooring.
Things began moving, steel creaking, tools rolling around. The locals didn't even look up. And laughed, hard when I asked what the ******* happened. That was the last time I worked in CA. Ok, so it was a 3 or so on the Scale. Don't give a damn!
Look, no matter what those lunatics who live there say.
THE GROUND IS NOT SUPPOSED TO MOVE!!!!