And when it does happen, the hardest hit areas will lean heaviest on places like hospitals and medical centers.
[Ads /]
"Hospitals have unique building standards that are much more rigid and more complex than any other building," said Liz Cochran, who is the chief operating officer for Adventist Health in Glendale.
Cochran showed Eyewitness News around the hospital's campus, to see how the buildings there and the staff are prepared to handle a major earthquake.
"The operations: electric, water, heating and air -- everything that you need to sustain and keep your operations going -- would not be impacted," she said.
The key to earthquake safety: seismic reinforcements, which are structural add-ons to make sure buildings don't collapse and utilities don't fail.
"In the event of a major catastrophe," Cochran said, "this is the place that you'd want to be."
But that isn't necessarily the case for other local hospitals.
[Ads /]
There are nearly 1,100 hospital buildings scattered throughout Southern California, and they are not all built to the same standards.
Click on the blue dots to check out the rating for each hospital, then click the arrows to flip through the ratings for each building.
CLICK HERE IF VIEWING IN APP
The California Office of Statewide Health Planning and Development rates these medical buildings for seismic safety risk on a scale from 1 to 5.
One is deemed to have the highest risk of collapse and 5 - the least risk of collapse.
Of those 1,100 Southern California hospital buildings, 376 were rated as a 1 or a 2, which is more than a third.
"Our hospital is built to meet strong, rigid standards for earthquake safety codes," Cochran said.
According to the state, Adventist Health Glendale has 15 buildings on its campus. Together they rate an average of 3.5 on the state scale.
[Ads /]
Cochran said the hospital has enough stored food, water and fuel to run at full capacity for five days. It also has a designated command center, and staff are trained to follow an established earthquake protocol.
Keep in mind, one place you don't want to be during an earthquake is an elevator. The ones in Adventist Health come with a built-in seismic safeguard.
When it's triggered, it brings the elevator to the next closest floor, opens the doors and locks down.
It's important to note hospitals receiving lower ratings on the seismic safety risk assessment are not breaking any laws, but the clock is ticking.
Most of the buildings with a rating of 3, 4 or 5 won't need to make any changes to meet requirements.
But, those buildings with a 1 rating have only until next year to make changes. Those with a 2 rating have until 2030.