Drills were planned all over the state, including a Northridge Target store, where shoppers ducked for safety at 10:20 a.m.
It could happen anywhere at any time and that is why millions across the state are preparing themselves for the worst with this drill.
"Basically, people usually panic, so I think this is very necessary. I think something like this should be done every year," said shopper Binoy Joseph.
The drill is now in its fourth year - four relatively quiet years in terms of real earthquakes, and that makes these drills even more important.
"Immediately following an earthquake, everybody rushes out and does what they're supposed to do, but it doesn't take long before we've forgotten, so this annual event is a great time to remind people," said Jeff Primes with Ready America.
The earthquake simulator, which was situated at the Target parking lot, gives you a pretty good idea of what the ground feels like during an earthquake.
When an earthquake hits, Mark Bethien with the SoCal Earthquake Center advised to get down low to protect yourself from things that might fall.
If you can't get under a table, cover your head and neck. If you are able to get under a table, you should hold on so that if the table starts to move, you stay with it and remain covered and protected.
Also, people should have emergency supplies handy like food and water to last at least a couple of days.
"The fire department and emergency responders tell us they're not going to be there to take care of you. You need to be self sufficient for at least three days," said Primes.
Drill organizers said approximately 8.5 million people participated in Thursday's earthquake-readiness drill.