West Coast Residents Seriously Underestimate the Threat of a Catastrophic Earthquake, Survey Finds

A crack left on a highway in the wake of last week’s major earthquakes near Ridgecrest, California.
Photo: AP

As last week’s major earthquakes in Southern California reminded us, we humans are still at the mercy of the geologically-active planet we live on. But despite the ever-present seismic threat, there’s a lot more West Coast cities could be doing to prepare their infrastructure and citizens for disaster, like implementing stricter building codes and restrictions and better early warning systems.

A new survey suggests a possible reason they aren’t doing more faster: many Americans living in quake-prone places seem relatively unaware of the threat they face. And that lack of knowledge or concern could help explain why greater earthquake preparedness isn’t at the top of most voters’ priority lists.


“For decades, social scientists have asked why is it the case that people who live in areas like San Francisco... don’t they demand stricter policies aimed at preventing the effects of major quakes,” Matt Motta, a political scientist at Oklahoma State University, told Earther.

Indeed, while the state of California does have building codes to protect its people and infrastructure from seismic hazards, many experts consider them woefully inadequate. As a New York Times report pointed out last year, San Francisco’s downtown has become dramatically more vertical in recent decades, but fifty-story skyscrapers have the same strength requirements as five-story buildings, and nobody knows how well they’ll hold up to the geologic inevitability of a major earthquake. LA, meanwhile, is home to thousands of “soft-story” buildings potentially at risk of collapse during a big quake.

Motta and his collaborator Andrew Rohrman, a civil engineer at the University of Massachusetts Amherst, suspected the reason the seismically-vulnerable public doesn’t demand its elected officials do more to prepare for earthquakes might stem from a simple lack of awareness.


To test that hypothesis, they surveyed 855 West Coast residents in the fall of 2018, asking them to judge the probability that an earthquake could cause catastrophic damage in their area on a scale of 1 to 100, and compared the responses to a metric showing the actual probability of ground shaking at their zip code. And they found that, well, people were not the best judges of the earthquake threat they face. Overall, those living in areas most susceptible to catastrophic earthquake damage only seemed “modestly more concerned” about the hazard than folks living in much safer areas, according to the paper published this week in the journal Behavioural Public Policy.


“To put it in correlational terms, we found a moderately positive relationship between increased actual and increased perceive risk,” Motta said. But, that relationship tailed off at the high end, with respondents living the most at-risk zip codes feeling no more threatened than those in comparatively safe locales.

Not only are people in the most quake-prone areas low-balling their own risk, they aren’t clamoring for policy solutions like building code requirements and development restrictions, which the survey also asked them about. Overall, the authors found “no discernible relationship” between actual quake hazard and policy attitudes. With one key wrinkle: Those Americans who live in the most quake-prone areas and accurately judge their risk of a seismic catastrophe were significantly more likely to support preventative policies.


Motta said a key area for future research will be to determine why the disjuncture between actual and perceived hazard exists; whether it’s sheer ignorance or what he described as “motivated cognition,” which is to say, people being aware of their risk and choosing not to act on it, a dynamic we’ve seen play out with vaccines and public health. But if it turns out that people are simply unaware, public education campaigns could go a long way toward generating public support for hardening West Coast against quakes.

And pushing politicians to do more before another magnitude 7 quake strikes seems like a pretty good idea.


“People like it when politicians respond to disasters,” Motta said. “But we don’t care nearly as much about the preventative side. I think what we observed last week in Southern California should be a wake-up call.”

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Maddie Stone

Maddie Stone is a freelancer based in Philadelphia.