Oct. 19 (UPI) -- The world's largest earthquake drill will take place on Thursday, giving millions of people worldwide the chance to brush up on how to react when a temblor strikes nearby.
The Great Shakeout, which started in California in 2008, had 20.3 million people registered to participate worldwide in Thursday's event -- meant to encourage people in earthquake-prone areas to practice the 'Drop, Cover, and Hold On' method.
The method recommends people to drop to the floor, anchor themselves down to the ground, cover under a table or a desk and hold on until the quake ends.
The Southern California Earthquake Center partnered with U.S. Geological Survey to create an earthquake drill similar to what would happen if a 7.8-magnitude earthquake occurred along Southern California's San Andreas fault.
Drills will take place primarily in schools, universities and colleges, state and local government facilities, healthcare centers and businesses and will last for at least a minute.
A study by the U.S. Geological Survey in 2014 found that the probability of Southern California experiencing a magnitude-6.7 earthquake or stronger by 2043 is 72 percent.
"There's not a single part of the United States that can't have an earthquake," Lori Dengler, an emeritus professor of geology at Humboldt State University in Northern California, told NBC.
"We're all at risk," Dengler said. "The real important thing about Shakeout is developing the muscle memory to do the right thing when the ground is shaking, and the right thing is to basically not move."
Some 55 million people participated in all of the Great Shakeouts drills in 2017, compared to 55 million in 2016.