How big is the earthquake that filmmakers will unleash in their summer thriller “San Andreas”?

So big it will be felt from California to the East Coast. So big it will rock the Richter Scale at numbers never seen. So big it will turn Hoover Dam into a soggy rock pile and threaten to immerse the Golden Gate Bridge under a wave of biblical proportions.

The Warner Bros. release, starring Dwayne Johnson and directed by Brad Peyton, is so devastating that scientists note there are multiple instances in which the make-believe quake rocks the truth.

That’s not to say seismologists don’t want to see the movie. They do. They even hope “San Andreas,” due in theaters Friday, will become a “teachable moment,” compelling inattentive denizens of the quake-prone West to learn survival techniques and prepare themselves for the “Big One.” The experts worry, though, that the cinematic shaker will so overwhelm audiences that some people might decide that making preparations would be useless.

“I am looking forward to seeing this, and I am expecting to have a good time,” said Tom Jordan, a USC professor and director of the Southern California Earthquake Center. “As long as people don’t think of it as realistic portrayal of what happens in a quake, we are OK. And why would they? It’s Hollywood.”

Producer Beau Flynn talked to Jordan and other experts early in the making of “San Andreas.” “There are things they are going to say are embellished,” Flynn acknowledged. “But it’s not a documentary, and I have always been very upfront about that.”

Flynn said, importantly, that his film will show how people should “drop, cover and hold on” in the midst of a quake. And he believes it will inspire many to prepare their homes and offices and to become more supportive of seismic research.

“I hope people have fun at the movie and an intense thrill ride,” Flynn said, “and then look up what they should be doing and what could really happen in a quake.” To enhance the chance of the latter, the film’s hero, Johnson, has filmed public service announcements in which he delivers the “drop, cover and hold on” safety mantra.

While there is plenty of room for concern about real quake-related threats, the experts said their look at the “San Andreas” trailers suggests that the film and science will diverge in several places (Warning: SPOILERS):


“San Andreas”: Two quakes, one magnitude 9.1 and one a 9.6 on the Richter Scale, devastate the West. The second cinematic shaker would be bigger than the 9.5 Chilean quake of 1960 that is the biggest in the history of such measurements.

Science: Estimates suggest that a temblor on the San Andreas Fault in California would top out at a maximum of about 8.3, said USC’s Jordan. Even that magnitude is unlikely, unless there is movement along the vast majority of the fault, which runs much of the length of the state.


“San Andreas”: A yawning fissure that appears to be about 30 feet wide rips apart the California countryside.

Science: Quakes are caused by tectonic plate moving against each other, not pulling apart, says seismologist Lucy Jones of the U.S. Geological Survey. While there will be secondary cracks in the earth, images of gaping openings are the stuff of imagination, not fact, Jones said. “People love this idea of earth opening up and swallowing something up. It attaches to primal fears,” said the seismologist, who attended Tuesday’s “San Andreas” premiere in L.A. “But you can’t have an earthquake in that situation.”


“San Andreas”: The Golden Gate appears in danger of being washed away under a massive wave.

Science: Tsunamis don’t look like traditional waves pumped up on steroids. They appear more like a sudden and massive increase in sea level. “It’s both absurdly too large and it’s a wave rather than an increase in the level of the ocean,” Jones said of “San Andreas’s” wall of water.  Not to mention that the San Andreas is not positioned to cause a tsunami. “Now we are in fantasy territory,” Jones tweeted from the premiere.


“San Andreas”: The vast majority of large buildings across the center of Los Angeles appear to crash to the ground.

Science: Even in a Great Quake, most seismically reinforced structures will remain standing, though some buildings are likely to collapse, while others probably would suffer extensive damage. “We expect serious damage to 1 in every 16 buildings in a real San Andreas EQ,” Jones tweeted Tuesday. “The movie damage is over the top.”

Other “San Andreas” images, such as widespread fires following the big shake, are more realistic, the experts said. A 2008 quake simulation in the L.A. area envisioned a big temblor touching off more than 1,000 fires. The simulation suggested emergency crews would struggle to respond because of disrupted water service. “Fire is probably one of the biggest dangers we face,” Jordan said.

Both Jones and Jordan were consulted early on by the “San Andreas” filmmakers, though neither was an official adviser on the film. Both experts said their impressions of the final product were limited because they had seen only an early script and the film’s trailers.

Jordan said he’s worried that the fictional earthquakes may look so overwhelming to some people that they decide it’s pointless to prepare. “We don’t want people to think earthquakes are so bad that there is nothing they can do and that they should just submit, in effect, to the hand of God,” he said. “There are things they can do.”

Producer Flynn said he takes quakes seriously, having arrived in California just months before the 1994 Northridge shaker. He was so unnerved by the tumbling objects and feeling of helplessness back then that he almost moved back East. Instead, he keeps earthquake kits in both his car and home and maintains a telephone land line, largely out of concern that mobile service will go down.

“But it’s surprising how few people in California prepare,” said Flynn, adding that he hopes “San Andreas” prods people to get ready. The public can get more information at websites like shakeout.org. “We look forward to this movie perhaps being a teachable moment,” said USC’s Jordan. “If the movie excites people’s interest, then we can provide people with some, perhaps, more realistic information.”

Hollywood and the halls of academe seem more in sync on another of the film’s themes: asking audiences where they will be, who they will be with and what will be most important when the Big One hits. “I think there is a good emotional message in there,” said Jones. “We never know what is going to happen and how it is going to change lives. So be ready.”