The Big One: How They Know It’s Coming, and How We Can Prepare for It

I wrote this article for a science writing course I took in winter 2018, while I was still working for Oregon Sea Grant. 

The Big One: How They Know It’s Coming, and How We Can Prepare for It

A popular bumper sticker says, “If you’re not angry, you’re not paying attention.” There should be one that says, “If you’re not scared, you’re not paying attention.”

Because an earthquake is coming.

And it’s going to be big—maybe the biggest ever to strike the U.S.

And the earthquake and accompanying tsunami are going to devastate coastal and inland towns and cities and injure or kill a lot of people.

And it’s going to happen right here, in Oregon.

“Yeah, yeah,” you say. “People have been predicting for years that California will fall into the ocean, and that’s never happened. Why should we believe this is gonna happen? Because some scientist says so?”

Well, actually, yes. In fact, several dozen scientists say so, including one who predicted the massive quake that devastated Tohoku, Japan, in March 2011. His name is Yasutaka Ikeda, and in 2005 he told his fellow geologists at a conference in Hokudan, Japan, that the nation should expect a magnitude 9 earthquake in the near future. Ikeda’s presentation was “met with polite applause and thereafter largely ignored,” wrote Kathryn Schulz in her 2016 Pulitzer Prize-winning New Yorker article, “The Really Big One.”

Six years later, a magnitude 9 quake hit Tohoku, killing more than 18,000 people, devastating northeastern Japan, precipitating the meltdown of the Fukushima nuclear plant and causing an estimate $220 billion in damage, says Shulz.

How did Ikeda know such a big quake would strike Japan? And how do he and other scientists know another big one—perhaps an even bigger one—will eventually hit the Pacific Northwest?

An upended house is among the debris in Ofunato, Japan, following the magnitude 9.0 earthquake and subsequent tsunami on March 11, 2011. (U.S. Navy photo by Mass Communication Specialist 1st Class Matthew M. Bradley [Public domain], via Wikimedia Commons)

The answer lies in recent findings about something called the Cascadia Subduction Zone (CSZ), a fault line several hundred miles long off the Pacific Northwest coast. The term “subduction zone” describes a phenomenon where one tectonic plate—a slab of mantle and crust—is sliding underneath, or subducting, another. At a slow enough pace, the movement of the plates is virtually undetectable—and harmless. At a fast-enough pace, in just the right place, the movement can result in a “full-margin rupture,” triggering an earthquake of magnitude 8 to 9.2. In combination with the resulting tsunami, a magnitude 9.2 quake would result in an estimated death toll of 13,000, says the Federal Emergency Management Agency (FEMA). Another 27,000 would be injured.

OK, so what are the chances of such a large quake happening? And when can we expect it? According to Chris Goldfinger, a professor of geology and geophysics at Oregon State University (OSU), the odds of such a large quake happening in the next 50 years are one in three. How does he know? Stories. Geological stories. Indigenous peoples’ stories. And Japanese stories. All of which point to a magnitude 9 earthquake and tsunami happening 318 years ago—9 p.m. on January 26, 1700, to be precise.

“Pffft,” you say. “Just because there was a big earthquake 318 years ago doesn’t mean there’s going to be another one.” True. But…there wasn’t just one earthquake. In fact, says, Goldfinger, core samples of the seafloor indicate that over the past 10,000 years there have been 41 CSZ earthquakes—a recurrence interval of 243 years. Based on that interval, there should’ve been an earthquake somewhere around the year 1943 (the sum of 1700 + 243). But there wasn’t. So, we’re about 75 years overdue.

Or are we? As Shulz writes, “Recurrence intervals are averages, and averages are tricky: 10 is the average of 9 and 11, but also of 18 and 2.” Thus, that 243-year figure could be way off; the interval could be, say, 500 years. Or it could be 100 years. No matter how one fudges the numbers, however, statistically speaking, with the current interval at 318 years (versus the average of 243 years), one could rationally assert that we’re already pushing our luck.

Having myself experienced only moderate tremors from a distant earthquake (which were scary enough, thank you very much), I am not qualified to describe what to expect of a big, local earthquake. My wife Jules, however, experienced a magnitude 6.7 quake in 1971 in greater Los Angeles, and she said the ground around her house became “fluid…like riding on a flying carpet,” accompanied by “an extremely loud noise, inside your body, not just in your ears.” Goldfinger, who was in Kashiwa, Japan—about 200 miles from Tohoku—when the 2011 earthquake struck, likened the feeling to “driving through rocky terrain in a vehicle with no shocks, if both the vehicle and the terrain were also on a raft in high seas.”

What might we expect from a magnitude 9 or greater CSZ quake in Oregon? Shulz’s article lays out perhaps the most graphic—and terrifying—scenario imaginable, including the failure of the power grid; the rupturing of gas and water lines; the demolition of homes; the collapse of buildings, schools, bridges, railways, airports, fire stations, and hospitals; landslides; fires; flooding; dam breaches; hazardous material spills; and so on.

Not a pleasant picture. But it’s just such graphic descriptions that get people’s attention and motivate them to take action. Over the past few years, articles such as Shulz’s, along with subsequent pieces in The Oregonian and Willamette Week and videos such as Oregon Public Broadcasting’s Unprepared, have provoked perhaps the greatest surge in earthquake preparedness efforts ever seen in Oregon. Homeowners are hiring contractors to bolt their houses to their foundations. Building owners are enlisting engineers to retrofit their buildings for an earthquake. Developers are incorporating earthquake resistance into their building designs, at no small cost. Extension agents are teaching residents of coastal towns where to run in the event of a tsunami. Coastal and rural communities are securing funding from county and federal agencies for emergency caches stocked with survival supplies and communication devices. Individuals and families are assembling or purchasing their own emergency supply kits, to help them survive for days or weeks. A Washington newspaper, The Bellingham Herald, published a fictionalized, novella-length account (serialized in 27 installments) of what life might be like following a magnitude 9 CSZ quake.

This emergency supply cache, located in the Coast Range community of Kings Valley (where I live), is stocked with food, water, water purifiers, sanitation supplies, tents, blankets, first-aid kits and even “ham” (amateur) radios, to help local residents survive and communicate with the outside world, says Jamon Ellingson, who helped secure funding for and coordinate placement of the cache (next to the Kings Valley Charter School). (Photo by Rick Cooper)

Sea Grant Extension Coastal Hazards Specialist Pat Corcoran (front left) joins colleagues for a tsunami evacuation walk up to Safe Haven Hill in Newport, Oregon. Planning and practicing on-foot evacuation is an important part of earthquake and tsunami preparedness. (Photo by Mark Farley, Oregon Sea Grant)

In short, people are starting to take the warnings seriously.

But is that enough? Shouldn’t somebody be working on, say, finding a way to accurately predict “The Big One”—or at least a way to predict how and where it’s likely to happen? Coastal residents, in particular, would benefit from the latter, since they’ll have to deal with both an earthquake and a tsunami.

Unfortunately, predicting with any accuracy when a quake will strike is virtually impossible at present, due to geology’s fickle nature. However, researchers think they may be able to predict not just where and how the quake will strike, but how an accompanying tsunami will impact the surrounding area. One project, funded by Oregon Sea Grant (full disclosure: my employer), is looking at historical evidence of tsunami inundation along the Oregon coast to help determine how inundation in various CSZ rupture scenarios might affect low-lying coastal areas. Principal investigator Andrew Meigs, a professor of geology and geophysics at OSU, says the resulting information could help inform next-generation tsunami inundation models and increase coastal community resilience.

Resilience will come in especially handy for coastal residents, since they’ll be on the front lines when a tsunami strikes, about 15 minutes after the quake begins. As Shulz points out, as natural disasters go, a tsunami may be the closest to being unsurvivable. Perhaps the only way to survive the tsunami resulting from a magnitude 9 quake is to outrun it.

A sign directs people to seek higher ground on Safe Haven Hill in Newport in the event of a tsunami. Notably, the logo and design for this and similar signs, which are used in inundation zones around the world, are the product of a collaboration between former Oregon Sea Grant Extension Specialist Jim Good and former OSU Extension Graphic Designer Tom Weeks. (Photo by Tiffany Woods, Oregon Sea Grant)

Another possible way to survive a tsunami is to take shelter in a so-called “vertical evacuation building,” which at this point is purely theoretical. We may get a chance to find out if it works, however, when OSU’s planned Marine Studies building is completed. The $58 million, 72,000 square-foot building, designed to survive a magnitude 9 quake and serve as a 48-foot high vertical evacuation shelter, will be built next to OSU’s Hatfield Marine Science Center in Newport—smack dab in the middle of a tsunami inundation (or flooding) zone. Despite objections from the state geologist and more than a dozen OSU faculty members, including Goldfinger and Sea Grant Extension Coastal Hazards Specialist Pat Corcoran, university leaders determined not only that the site was the best option for several practical reasons, but that the building could help save up to 900 lives in the event of a tsunami.

In response to an Oregon Sea Grant tweet I posted about the March 15, 2018 “construction launch” of the new building, Goldfinger tweeted, “Unfortunate that the corrupt politics of a donation and state funding led to building a school in a tsunami zone when better, cheaper and much safer alternatives were at hand. This was opposed by OSU Marine and Geoscience faculty, the State Geologist, OSSPAC [Oregon Seismic Safety Policy Advisory Commission] and many others.”

A decidedly more affirmative response to the same tweet came from OSU Distinguished Professor of Zoology and former NOAA Administrator Jane Lubchenco, who tweeted, “A wonderful change [sic] to celebrate the amazing ocean studies available @OregonState new building; new energy; new opportunities!”

Back on the circumspect side, Corcoran told me the building might, indeed, survive a magnitude 9 quake and tsunami, but what then? All the surrounding buildings and infrastructure will likely be demolished and the roads and bridges rendered impassable, leaving those who took shelter on the roof of the Marine Studies building essentially trapped. It might’ve been better, Corcoran suggested, to have retrofitted the existing buildings and infrastructure for an earthquake and tsunami first, so the entire complex might serve as an evacuation shelter—and as a model for other vulnerable coastal areas.

This is an architectural illustration of OSU’s planned Marine Studies building, which will be built in the tsunami inundation zone near OSU’s Hatfield Marine Science Center in Newport, Oregon. The building is expected to serve as both a lab and classroom space and a “vertical evacuation” shelter. OSU held a well-attended “construction launch” ceremony at the site on March 15, 2018. (Graphic courtesy of OSU)

Since most buildings are not vertical evacuation shelters, your best bet for surviving a big earthquake and tsunami—and the resulting collapse of essential services and infrastructure—is to prepare in every way you possibly can. But what does that mean, exactly?

First of all, says Corcoran, we should expect that a big quake will happen in our lifetime, but try not to be fatalistic. He suggests that instead of preparing for a magnitude 9 quake, we prepare for a smaller one, which is more likely. “Preparing for a 9 doesn’t ensure that the next one will be that extreme,” he says. “The odds are that the next one will be average sized. That is far less impactful. Prepare for a manageable 8 [which is ten times less powerful than a 9].”

For coastal residents, who could be isolated and without services for weeks following an earthquake and tsunami, Meigs says there are two immediate actions they can take to enhance their resilience. “First, prepare a two-week (or longer) cache of food, water and other supplies—sleeping bags, tents, propane for stoves, etc.—for use in the period immediately following the event. Second, identify where the tsunami inundation zone is with respect to places of employment, recreation and living.” Meigs adds that it’s a good idea to know your evacuation routes and congregation points, develop an action plan, and practice that plan enough so that, when the event occurs, you can act without having to think. For more ideas on how to prepare for the before, during and after of a big earthquake, check out the helpful tips provided in this article from The Oregonian.

Feeling overwhelmed? Me, too. It’s a lot to think about, preparing for something so big and so abstract, especially for those of us who’ve never experienced a large quake. Hoping to get it distilled down to something easier to grasp, I asked Corcoran what’s the one thing he recommends we do right now to prepare for The Big One. His response: “Assume that you will eventually emerge okay. What will you wish you had done, that you haven’t done yet? Do that now.”

References

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