​"San Andreas": Fact or fiction?

Widespread destruction in the new disaster film, "San Andreas."

Warner Brothers

The film "San Andreas" is shaking things up at the box office. But would a REAL earthquake actually flatten California just like in the movies? John Blackstone talked to the experts:

In the movie "San Andreas," Hollywood envisions the destruction of Hollywood (along with much of the rest of California).

"This whole chunk of land will be decimated," says Paul Giamatti, playing a Cal Tech seismologist.

In this disaster movie, the disasters themselves are blockbusters, as one powerful 9.1 earthquake triggers and even bigger one.

Since the movie came out, U.S. Geological Survey seismologist Lucy Jones has been reassuring Californians much of what they see on the screen - like the San Andreas fault splitting open, or Hoover Dam collapsing -- can't happen here.

"There are pieces" of the film that could be real, said Jones. "The idea that we could trigger an earthquake -- have a big earthquake in L.A. that triggers a big earthquake in San Francisco -- that is real. Magnitude 9s are not real."

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The San Andreas fault literally rips California apart at the seams in the new disaster movie, "San Andreas." Warner Brothers

When real earthquakes hit California, reporters call on Jones for the facts. That has made her a bit of a celebrity in Los Angeles, and explains why she was on the red carpet for the premiere of "San Andreas."

"A seismologist on the red carpet, that is groundbreaking!" said Blackstone.

"It is very Los Angeles, isn't it?" laughed Jones.

As she watched the movie, she tweeted to her followers what could happen -- and what couldn't happen.

Fact or fiction: the earth divides? "That one is absolute fiction. If the earth could open up, there would be no friction, and then there'd be no earthquake," Jones said.

Fact or fiction: most of the high rises in L A coming down? "Most coming down, fiction. A few, potentially fact."

Huge tsunami hits San Francisco? "Here's where we start entering fantasy territory. Tsunamis are not cresting waves. They can't be bigger than the ocean is deep."

Feel a California earthquake on the East Coast? "Sorry, ain't going to happen. The Great 1906 Earthquake that devastated San Francisco was felt into Nevada, and that is as far East as it got."