San Andreas : Separating 5 Facts From Earthquake Fiction

Sometime in the future, cafés in Kathmandu will be abuzz about a devastating magnitude-8 earthquake, except this time the temblor will have been half a world away, in California, where the San Andreas Fault will have finally ruptured after a long period of dormancy.

Although criticism of the recently released film San Andreas from scientific circles is a certainty, as a state seismologist for Nevada, with responsibility for monitoring Nevada and parts of eastern California, I welcome this movie and hope it marks the beginning of a serious conversation about the real consequences of a large earthquake in modern America. Whatever the scientific flaws of San Andreas may be -- and they are plenty -- the consequences of a large urban earthquake remain unnerving.

With a little help (OK, a lot of help), Hollywood went with the "wall-to-wall" scenario and ruptured the entire San Andreas Fault, extending from near the Mexican border almost to Oregon. This kind of rupture has never been seen and is a highly unlikely scenario given both historic and paleo-earthquake records. And in reality, the magnitude would be closer to 8.3, not 9 as depicted in the movie.

Of course, Hollywood paints a bigger-than-life picture and plays with the truth in order to entertain, so let's try to separate fact from fiction with this latest take on the disaster genre.

Here are five truths about the depictions in San Andreas:

  1. The trigger: Can a large earthquake in Nevada trigger the San Andreas Fault or knock down Hoover Dam like in the movie? Western Nevada and eastern California occupy the Walker Lane, which has some fault lines that are capable of generating quakes with magnitudes up to about 7.5 (just not near Hoover Dam). Larger Nevada earthquakes can trigger other regional earthquakes; it happened in reverse in 1992, when the magnitude-7.3 Landers quake in eastern California likely triggered the magnitude-5.7 Little Skull Mountain earthquake north of Las Vegas about a day later. But the San Andreas Fault? Not likely.

  • The tsunami: Will a towering, earthquake-generated tsunami inundate California? Most of the San Andreas Fault is landlocked, and when it heads offshore, it occupies shallow waters. In the 1906 earthquake a less-than-a-half-meter wave was generated. Strong shaking could trigger landslides offshore that could spawn a tsunami, which appears to have happened after an 1812 earthquake near Santa Barbara, which resulted in a tsunami wave several meters in height. In neither case is it a towering megatsunami that inundates coastlines and big bridges.
  • The crevasse: Most large earthquakes with ground rupture have associated tension cracks that can, at times, get large enough to place an arm into, a far cry from the chasm seen in San Andreas. The San Andreas Fault will not swallow up cars, people or buildings.
  • East Coast shakeup: Will the East Coast feel a West Coast earthquake as San Andreas portrays? Although Washington, D.C., might seem to be the epicenter of dysfunction of late, it gets to sit this event out in terms of ground shaking from a large West Coast earthquake. When both political parties see the FEMA bill from the next major San Andreas quake, with damages estimated at $200 billion or more, only then will politicians start to shake.
  • Nothing left standing: Will California's skyscrapers collapse? As two of our Nevada Seismological Laboratory graduate students can attest after recently riding out the magnitude-7.3 "aftershock" in Kathmandu, even with their poor building standards, destruction in Nepal looked nothing like that seen in San Andreas. Here's a prediction: Most damage associated with future U.S. earthquakes will be focused on unreinforced masonry (URMs) buildings and soft-story structures, not modern buildings, which will shake, rattle and sway but not necessarily collapse -- a far cry from scenes in the movie.
  • As a seismologist and the director of the Nevada Seismological Laboratory at the University of Nevada, Reno, and as a fan of really good movies, my hope is that Dwayne Johnson, the actor known as "The Rock," delivers a good blockbuster hit that does not resemble Hollywood's 2003 science-fiction flop The Core in any way, shape or form.

    With many Americans getting their science news from nontraditional sources such as The Daily Show or Vice, maybe The Rock can help start this conversation. California in particular is leading the nation in innovative approaches to preparedness and mitigation associated with "The Big One." California gave rise to the nationwide Great ShakeOut annual earthquake exercise; Nevada (the third most seismically active state in the United States) was the second state to join. San Francisco recently hired a dedicated Resilience Officer, a first, to ensure minimal downtime after the next big quake. What is your city doing?

    Nascent earthquake-warning systems, both public and private, are running in the Golden State, and we are beginning to institute systems in Nevada. The California Governor's Office of Emergency Services, along with federal (e.g., USGS and FEMA) and local partners, routinely run exercises to out-fox the next big earthquake. Other entities such as the California Integrated Seismic Network, California Earthquake Authority and California Seismic Safety Commission play their integral roles in all things earthquake.

    Nonetheless, this system is predicated on an informed public, and maybe, just maybe, San Andreas can be that catalyst in California's all-in strategy and an impetus for other states to be prepared.

    Graham Kent, Ph.D., is a seismologist and director of the Nevada Seismological Laboratory at the University of Nevada, Reno. He has conducted research on the San Andreas Fault in Southern California and around the world.