Must have been the one. My poor little house feels like its just going to be shaken apart by all these earthquakes. My first thoughts while it was going on (seemed to last for about 15 seconds or more which is quite a bit when you freeze and hold on listening to everything rattle lol) was thinking about the parking garage my shop is in. Looking at how it's built I don't think it could handle much shaking. All that hard work, and possibly me or my employees, squished flat under tons of cement. Not a reassuring thought. Remembering back on those larger quakes in California seemed that the parking garages were one of the structures most likely to collapse.
Just from the look and feel of your shop, I think I would have an emergency plan for each of our catastrophes (tornado, fire, and earthquake). All pretty simple for your place, I would think. Maybe a drill or two...?
Fire - go out the front door, and across the street (west). Then call fire department....
Earthquake - go out the front door, turn left to clear the building, then diagonally southeast across the parking to avoid the falling Equity bldg and the tall one next to it. This one is tough because of all the tall and semi-tall buildings around.
Tornado - easiest of all....just bend over and kiss your donkey goodbye.... Not really - inside room - might be able to build a "safe" wall fairly easily - Texas Tech shows how. Takes some extra anchoring to floor, some 2 x 4 additions (minor). 3/4" plywood and some 12 ga sheet metal. If you remodeled coming in to the place, this is probably something you could do.