People around the United States and in dozens of other countries took part last week in an earthquake drill called the Great ShakeOut, an event that teaches them what to do when a real earthquake strikes.
Drop, cover, and hold on. Those are the instructions for an earthquake.
In Southern California, the simulated quake had its epicenter at Biola University.
The drill's goal is education, said Los Angeles County Fire Captain Tom Richards.
“We're training today to prepare for a major earthquake, and our goal is to stress to the citizens of the county of Los Angeles, and everywhere for that matter, to prepare," Richards said.
Students played the injured and the dead in the emergency drill, which has been conducted for seven years. Nursing students helped first-responders manage the casualties.
It was a realistic scenario for students who entered an earthquake simulator, a truck with hydraulic lifts that create violent shaking.
Student Jenna Golden said it was scarier than she expected.
“It was really surprising. I didn't think it was going to be that scary or that violent at all, or last for that long," Golden said.
The simulated 6.7-magnitude earthquake was the same strength as the deadly quake that shook the Los Angeles suburb of Northridge 20 years ago.
But most of these students are too young to remember it.
Desiree Sanchez, 17, got a close-up look at a frightening scenario that she more often sees on newscasts.
“We always hear about it everywhere else, but we never hear about it here," Sanchez said.
What causes earthquake
Geologist Dale Schneeberger of Biola University explained that earthquakes are caused by a region's setting on the boundary of two plates of the earth's crust, which press against each other.
“And as a result, that energy builds up into the crust. And eventually, the strength of the rock will fail because it can't take any more energy put into it. It breaks, and we call that an earthquake," Schneeberger said.
Greg Renick of the California Governor's Office of Emergency Services said the dramatic re-enactment is a reminder of the many hazards of nature.
“We also have a high fire risk. When winter does come, we have the risk of flooding," Renick said.
The emergency drill shows that rescue efforts are never easy, but the Great ShakeOut is helping students know what to expect in a real earthquake.