What Do Scientists Say About 'San Andreas'?

Everybody born and raised in California has had a nightmare about "The Big One," the large earthquake that seismologists predicted would occur along the San Andreas Fault and bring unprecedented damage in its wake. The trailer for the movie San Andreas, starring Dwayne Johnson, makes this nightmare scenario more real than ever, depicting how an earthquake the magnitude of “The Big One” would devour the Los Angeles skyline, San Francisco’s Golden Gate Bridge, and the Hoover Dam. But how much damage could a San Andreas- style earthquake cause, according to actual scientists?

As Paul Giamatti’s character puts it in the film’s trailer, “The earth will literally crack open. You will feel it on the East Coast.” According to the Associated Press, the earthquake in San Andreas is a two-parter; an unknown fault near the Hoover Dam in Nevada causes a magnitude 9.1 earthquake in Southern California and then a magnitude 9.6 earthquake in Northern California. But according to Professor Tom Jordan, William M. Keck Foundation Chair in Geological Sciences at the University of Southern California, it’s not possible for earthquakes as big of a magnitude as the ones depicted in San Andreas to actually happen along the existing fault.

“It’s not possible to have earthquakes that big along the San Andreas fault,” Jordan explains to Bustle. Why? The fault isn’t big enough. According to the U.S. Geological Survey, the San Andreas fault is 800 miles long, running from Northern California to near San Bernardino, and 10 miles deep.

According to the USGS, a huge “mega quake” along the San Andreas just wouldn’t fit:

To generate an earthquake of 10.5 magnitude would require the rupture of a fault that is many times the length of the San Andreas Fault. No fault long enough to generate a magnitude 10.5 earthquake is known to exist. The largest earthquake ever recorded was a magnitude 9.5 on May 22, 1960 in Chile on a fault that is almost 1,000 miles long.

The largest documented earthquakes to have occurred along the San Andreas fault happened in 1857 and 1906, the latter is known as “The Great San Francisco Earthquake of 1906” and is estimated to between magnitude 7.7 and 7.9, according to U.C. Berkeley’s Seismological Laboratory. By comparison, the earthquake that hit Nepal last month was registered by the U.S. Geological Survey as a 7.8 on the Richter scale.

If you crunch the numbers on USGS's "How Much Bigger"? calculator, the extremely unlikely 9.6 earthquake that rattled San Francisco in the film San Andreas would be 63.095 times bigger and 501.187 times stronger than the Great San Francisco Earthquake of 1906. It would be more than 1.25 times bigger and roughly 1.4 times bigger than the 1960 Chile earthquake, known to be the largest earthquake ever recorded. The earthquake rattled Southern Chile’s coast and left more than 1,600 people dead and 2 million homeless, according to USGS.

Since the release of San Andreas last Friday, earthquake experts have weighed in on the film’s unlikely premise and debunked its myths. Could the impacts of a San Andreas earthquake be felt on the East Coast? Unlikely. USGS seismologist Susan Hough told the Associated Press that historical accounts of the 1906 San Francisco earthquake showed that those in western Nevada and southern Oregon could barely feel its tremors. The New York Times didn't publish its account of San Francisco earthquake until the next day at 12:15 a.m.

The film’s trailer depicts the San Andreas fault opening up the Earth, which some seismologists had issue with. USGS geophysicist Morgan Page debunked that myth to KRON; the San Andreas fault won’t open up, the fault is the boundary where two plates slide past each other.

USGS seismologist Lucy Jones took to Twitter on Thursday to live-tweet San Andreas, backing up Page that the movie's claim that the San Andreas fault opens up is false.

What else does San Andreas get wrong? According to Jordan, earthquake prediction science hasn’t yet reached the level attained by Lawrence Hayes, the film’s fictional seismologist.

“We typically know where all the faults are. We know how big the earthquakes can be and we know how frequently how they occur. But we have a very hard time pinning down when,” says Jordan.

So forecasting earthquakes days or even hours before they occur? That simply doesn’t happen.

What seismologists have been able to successfully predict is the likelihood of a certain magnitude of earthquake occurring. The magnitude 9 earthquakes in the San Andreas film may be unlikely for California, but a magnitude 8 earthquake is a real worry, according to Jordan, and could bring on considerable destruction as far loss to human life and property.

According to the Third Annual Uniform California Earthquake Rupture Forecast released in March, the likelihood of a magnitude 8 level earthquake occurring in Greater California in the next 30 years has raised to around 7 percent, from 4.7 percent since the last forecast.

One unexpected highlight in the report? Due to the 1906 earthquake, the Northern San Andreas fault actually has a lower chance of hosting another earthquake.

Despite its many flaws, seismologists seem to like the film for its ability to get the message out. Jordan, who’s seen the movie, said he enjoyed it. "It'll get people thinking about earthquakes," he says.

Other seismologists found several scenes in the movie, however unrealistic, to serve as useful reminders of how people needed to prepare in the event of an actual earthquake. For example, in the event of an earthquake, landlines, not cell phones, are your best bet.

One piece of advice you can actually heed from the film, according to Jordan? Even though they may be a departure from reality, one benefit of San Andreas and other films in the earthquake disaster genre is that they get people talking about earthquakes. Drop, cover and hold on. Second nature to anyone’s who’s participated in California’s “Great ShakeOut” disaster drills, the best method to avoid injury in an earthquake is to drop to the ground, take cover under a sturdy desk or table, and hold on until the shaking stops.

But other than that public service announcement, seismologists hope the film’s premise is unlikely to fool anyone. “I don’t think people who watch this movie are going to think this is going to actually happen in California,” says Jordan.

Image: Getty Images (2), Warner Bros