Debunking Science: San Andreas

Raul Monraz | November 4, 2015

Debunking Science: San Andreas

Last spring, an M9.6 earthquake wreaked havoc in California. The long overdue, gargantuan quake leveled the metropolises along the infamous San Andreas Fault line. Los Angeles, San Francisco, and their surroundings sunk into chaos. Unleashing violent tremors from deep beneath the earth, the disaster triggered fires, power cuts, and the mother of all tsunamis.

Rather than being petrified in fear, our Californian peers can assure us that they witnessed this catastrophe over popcorn and soda from the safe vantage points of darkened movie theaters, confident that Dwayne “The Rock” Johnson’s protagonist would save the day. San Andreas, Hollywood’s latest natural disaster blockbuster, played on the anxieties of many West Coast denizens by offering a glimpse of what is to come when The Big One — the anticipated mega-earthquake — actually hits.

Not counting Johnson’s unlikely stunts, the film got most of the generalities of emergency protocol right. As disasters strike throughout the film, characters know to drop immediately to the ground and hide below sturdy objects. Characters recognize the sea’s drawing in as a predictor of an incoming tsunami. Early warning systems cry loud across the coast, saving many lives by goading people up to higher ground. Fans watching San Andreas get a rudimentary course in emergency management: “What to do when Seismic Hazards, Inundations, and Tsunami hit you.”

Nevertheless, this film would probably not be a box office hit without some well-done but greatly exaggerated CGI. The dramatic implications of unrealistic events are enough to cause moviegoers to gawk in awe. With the aid of movie magic, the film perpetuates three big scientific inaccuracies: the magnitude of the earthquake and its consequences, the size and very occurrence of the tsunami, and the existence of a high-tech magnetic pulse model for predicting earthquakes.

In the movie, even the first earthquakes — between 7.0 and 8.0 on the Richter scale — produce much more damage than they would in reality. Additionally, seismic waves in the film violently shake and collapse a majority of city buildings; with gross inaccuracy, an M7.1 quake obliterates the Hoover Dam. In 2008, a panel of U.S. Geological Service experts modeled the impact of a big earthquake in the southern California area. The project predicted major structural damage, but mostly on buildings that fail to comply with building codes or that have not been adapted to withstand earthquakes. In all, few buildings would come to the point of total collapse, and most would be within 15 miles of the San Andreas Fault rather than spread far and wide.

Still, viewers who have not experienced a major earthquake themselves may take the destruction simulated in San Andreas at face value, since real-world media outlets similarly dramatize disaster damage. In their coverage, the buildings shown are typically those that have sustained the most damage during earthquakes, rather than those that have been left mostly unscathed. Even the most devastating earthquakes, such as an M7.9 one that afflicted Nepal last April, would not cause the majority of buildings to collapse: A survey by the Nepali Engineers Association found that only 20 percent of buildings sustained major damages from the quake. About 60 percent of the buildings struck down in the area were masonry-built and lacked steel structures, construction methods outlawed in California since 1933.

The film especially starts to wander into fiction when Paul Giamatti’s geologist character goes on national television to announce the onset of a “swarm event,” a string of unfolding earthquakes rippling from Nevada to San Francisco. According to his “magnetic earthquake prediction model,” the geologist warns Americans that The Big One will ultimately strike San Francisco with magnitude 9.6, and that its impact will be felt on the East Coast. Its force, he says, will be such that “the earth will literally crack open.”

Earthquake swarms are real: several earthquakes may in fact happen within a relatively short period of time. However, swarm event earthquakes typically fall within a given magnitude and do not have a distinguishable, main earthquake. While a swarm could account for the multiple quakes in the movie, the San Andreas quakes have magnitudes far higher than those of usual swarm earthquakes. For comparison: a swarm of 101 earthquakes took place from July to November in Nevada last year, with a maximum magnitude of 4.6 — far milder than the M9.6 quake predicted in San Andreas.

When it comes to tsunamis, even a small one is extremely unlikely to happen. The San Andreas Fault is located inland, far away from the coast. An earthquake must occur in the ocean floor or at least close to the sea for a tsunami to occur. Finally, the magnetic pulse predicting model is so far — unfortunately — only science fiction. If such a model existed, it would have been implemented already, as predicting these natural disasters would surely save many lives.

While we can appreciate San Andreas’ wake up call for preparedness, its science is implausible. The movie crosses into science fiction by greatly exaggerating the destructive power of a natural phenomenon and blatantly conjuring up impossible scenarios. Californians, you need not be Hollywood superstars to weather The Big One — just educate yourselves on earthquake safety and be ready.

Cover Image: Image courtesy of New Line Cinema.