Editor's Note: The story below was published in 2014. For the current version, check out our updated 2018 story.

Think of Oregon geology as a clock, measuring time in earthquakes—40 major coastal quakes over the last 10,000 years. Tick: a magnitude 8 on the Richter scale. (Bigger than the quake that killed 63 people in the Bay Area in 1989.) Tock: a magnitude 9. (Same as the 2011 quake that killed almost 16,000 in Japan.) On average, a major quake uncorks in this area every 243 years, the last one on January 26, 1700—314 years ago.

Right. We’re overdue.

When the next Big One does happen, a 700-mile chunk of tectonic plate known as the Juan de Fuca, stretching from British Columbia to Northern California, will slide beneath the North American plate, causing the entire Northwest coastline to sink by up to 6.6 feet. The resulting quake won’t be a California-style short blast of energy along a fault line in the earth’s upper crustal zone. It will be bigger, deeper, and longer: 3–4 minutes, with potentially dozens of aftershocks, some very powerful, for days, even months, later.

Hillsides will slide. Buildings will collapse. Roads will buckle. High-rises will sway. Bridges will crack. Some will fall. Pipes will snap. Within 20 minutes, the first of several 40-foot tsunami waves will wash the Oregon Coast’s low-lying towns away.

If our next “subduction zone” quake unleashes its full potential, it will be the worst natural disaster in US history. But there are crucial steps we can take, as individuals, families, and a community. Preparation may mean the difference between finding your loved ones or not; between sleeping inside your mildly damaged house or on a cot in a refugee center; between going hungry and thirsty for days or managing until supplies arrive. And, yes: between living and dying. For the Northwest, preparedness could mean the difference between bouncing back in years or not bouncing back for decades.

Officials are working hard on the problem. More than 160 scientists, engineers, and infrastructure managers volunteered thousands of hours of time to develop the Oregon Resiliency Plan, a blueprint for averting the worst scenarios and a quicker recovery. “[B]usiness as usual,” the panel concluded, “implies a post-earthquake future that could consist of decades of economic and population decline—in effect, a ‘lost generation’ that will devastate our state and ripple beyond Oregon to affect the regional and national economy.”

With their recommendations in mind, here’s a guide to what’s being done and what all of us should do. The Big One is inevitable—right now, or 50 years from now. What happens before and after is up to us.

1. What buildings will fall down?

We like old buildings and have a perennially weak economy. Result: Portland has about 1,800 “unreinforced masonry” (i.e., old brick) buildings, more than 40 of them schools or day cares. If not retrofitted, they are all likely to collapse. More modern steel and concrete buildings will stand, but that doesn’t mean they’ll be safe to enter or use postquake. What’s more, building codes assume short, quick, California-style quakes. How Portland’s modern buildings will fare in a subduction event’s longer shake isn’t well understood. The best seismic building system is called “base isolation,” in which buildings slide atop pads within a kind of tub. Japan has 6,400 base-isolated buildings that remained functional after the 2011 quake. Portland has one: Pioneer Courthouse, retrofitted in 2005.

What we’ve done: In 2012, Portland voters passed a $482 million bond to improve schools, much of it planned for seismic retrofitting. A 1998 bond allowed the Portland Fire Bureau to retrofit or rebuild all 30 of its facilities for the strongest earthquakes. The bureau also now has “urban search and rescue” squads on both sides of the river trained to find people in rubble. Multnomah County is in the process of planning how to choose shelter locations in the aftermath. “One of the biggest challenges in disaster planning is making a plan based on what people will do, not what you want them to do,” says Alice Busch, emergency manager for the Department of County Human Services.

What we should do: Steve Novick, the city council’s most aggressive preparedness proponent, wants urban renewal funds to retrofit the Pearl District and Old Town. Portland lets developers build bigger if they install eco-roofs, locker rooms, family-size apartments, and 15 other “bonus” options. Resiliency planners recommend adding similar incentives to encourage earthquake-ready buildings.

2. What about my house?

Wood-frame houses generally fare well in earthquakes. But of Portland’s estimated 152,000 single-family homes, 70 percent were built before the first seismic code in 1978. That means they probably are not bolted to their foundations—and will thus rattle off and be largely uninhabitable.

What we’ve done: With $100,000 in FEMA funds, Novick started a pilot program for 22 homeowners to bolt their houses down. He also did his own. Cost: $4,000. So did Carmen Merlo, director of the city’s emergency bureau, whose complicated foundation necessitated lifting her house. Cost: $25,000.

What we should do: Just do it. Anchoring most homes costs no more than $5,000. “If Phil Knight decided he cared more about earthquakes than curing cancer,” Novick quips, “he could pay for almost everybody to bolt their houses to their foundations.” Novick wants to require earthquake readiness disclosure for any home sale. (Astoria requires disclosures in known landslide areas.) He also is exploring requiring automatic gas shutoff valves in new construction. (LA already does.)

The Family Plan: When the big shake comes, you’re going to want to connect with your brood as quickly as possible. Sit down with your family and/or friends to discuss what to do. Imagine different times of day and scenarios—particularly who will be on what side of the river. Set up at least two places to meet: one outside of your home, the other outside of your neighborhood. Designate a contact—outside of Portland. Phone lines within and into the city will be jammed. Outbound calls, however, should be easier to make, particularly to other regions of the country. Aunt Myrtle in Kansas, or your college roommate who lives in Manhattan, can become a central information hub. Know your evacuation routes! Portland’s emergency planners have developed hazard maps for every neighborhood that include evacuation routes, hospital locations, and other emergency services. Have family documents organized and ready to grab and go. That means Social Security cards, insurance information, passports, and birth certificates. Get some bikes. Fuel might be tight for days, even months. You’ll need to get around. And what’s more fun than family bike rides? We won’t have Netflix for a while.

3. How will we get around?

By foot, bike, and boat, mostly. The region’s quake planners agree: people will be stuck where they are for quite some time. Prepare to bond with the people you’re with—whoever they are—or get walking.

BRIDGES: Top-heavy, counterweighted lift spans like the Hawthorne, Steel, and Interstate will likely collapse. So will ramps leading to just about all the bridges.

ROADS: Vast swaths of the city’s roadways, built on fill and alluvial deposits, will crack and sink.

THE TUNNEL: Highway 26’s West Hills Tunnel was built before seismic codes. It may prove impassable.

THE GEAR: All of the city’s road-clearing equipment is stored beneath the certain-to-collapse Fremont Bridge ramps. Seemed like a good idea at the time!

THE FUEL: Most of Oregon’s fuel supply arrives to the “Critical Energy Infrastructure Hub,” a six-mile stretch of fuel storage tanks and refineries next to the Willamette River between the St. Johns and Fremont Bridges—all built atop vulnerable fill and alluvial deposits. Several multinational energy companies are involved; some have seismically upgraded some of these facilities, others have not. Most fuel gets here by way of a single, vintage 1960s pipe from Washington—owned and operated by BP—beneath the Columbia and Willamette Rivers. The movement of the rivers could cause the pipe to snap. In other words, peak oil (and natural gas) may come a little early.

STANDING SPANS: The soon-to-be finished Tilikum Crossing and Sellwood Bridge are both built to withstand major earthquakes, as is the aerial tram.

THE BOATS: The Portland Spirit, tugs, and other rivercraft will become ferries.

THE HQ: Novick is pushing for $2.2 million to seismically update the city’s vehicle and equipment fuel storage tanks and open a new west-side emergency management center and equipment storage facility, possibly in the decommissioned SFC Jerome F. Sears Army Reserve Center.

4. What will we eat?

“Portland’s DIY mentality will help,” says Merlo. “The people who preserve their own food, ride bikes, catch rain water, raise chickens, and garden will thrive after an earthquake.”

Yes, it’s that bad. Consider:

1. The quake will shake the whole Northwest, from British Columbia to California.

2. Grocery and “big-box” stores built before the 1995 seismic-code upgrade are likely to suffer severe damage, according to Oregon planners.

3. I-5 bridges, highways, and railroad lines may not be passable.

4. Only one Port of Portland terminal (6) has been seismically retrofitted.

5. Anyway, the post-quake tsunami is likely to devastate the jetties at the Columbia River’s mouth, making the famously tricky bar crossing even more treacherous. Dikes and pilings protecting the river’s shipping lanes could collapse, making the lanes impassable.

6. Portland International Airport sits on the kind of loose fill that turns to jelly—a phenomenon known as liquefaction—in an earthquake.

7. FEMA’s primary emergency response airport is in Redmond, 145 miles away.

What we've done: Multnomah County has developed a task force—governments, restaurants, homeless organizations, churches, and others—to respond. “We’re on the cutting edge,” says Alice Busch of the county’s human services department. “We’re encouraging people to be self-reliant.”

What we should do: Retrofit critical routes. Create an inventory of World War II–style temporary bridges. Stock up.

Befriend a neighbor who makes kimchi. Could come in handy.

5. What will we drink?

Before Bull Run, booze was safer to drink than water. Turn the clock back. Your faucets (and toilets) will be dry for weeks, maybe months. The Bull Run dams are expected to survive, but 65 percent of the city’s water mains are brittle cast iron. Reservoirs will crack; treatment facilities and pump stations will fail. The result: a total loss of water pressure—both for drinking and for putting out fires. For the first couple of weeks, water will have to be pumped, purified, and trucked. Firefighters will pump the Willamette into 10,000-gallon tank trucks, or directly to fires with Portland’s three fireboats. Sewers will fail. Bucket-flushing toilets at home will only clog the system. Going au naturel, over time, will pollute the ground supply and river. Figure on a year to flush.

What we’ve done: The Portland Water Bureau has strengthened one conduit from Bull Run, with plans to update the other two in the five-year budget. New tanks completed at Powell Butte and Kelly Butte by next year and at Washington Park by 2020 (replacing the beloved open-air reservoirs) will be quake-proof, and the new Tilikum Crossing and Sellwood Bridge both carry water lines.

What we should do: Upgrading the entire system would be like rebuilding the city. Planners recommend a “backbone” of new pipes to critical care facilities, firefighting nodes, and distribution points. Next step: within five years, the Water Bureau will begin a $56.6 million seismically “hardened” water line across the Willamette. At home, invest in a storage tank or water purifier (see sidebar, left). The Portland group Public Hygiene Lets Us Stay Human outlines an emergency “two bucket” toilet system to maintain hygiene.

6. How will we communicate?

Smoke signals! Kidding. Well, maybe.

Phoning within the city, checking Facebook, and doing business may be difficult for weeks. Vulnerabilities range from major fiber lines running underground and over those damned bridges to wireless antennas sitting on liquefaction soils or on buildings that will collapse or be unusable. According to the Oregon Resiliency Plan’s analysis, restoring full communications will take up to three months.

What we’ve done: The city has established a network of 48 Basic Earthquake Emergency Communication Nodes that will be deployed in red-and-white tents in parks and open spaces throughout the city to receive shortwave radio transmissions.

What we should do: Get to know your neighbors, so when the shaking stops you have the beginnings of a cohesive community. Figure out the planned site of the nearest emergency node—find maps here. Designate a family contact outside the western states.

And join the safety net!

Portland’s population: 600,000. Professional emergency responders: 1,700. Do the math.

“You shouldn’t expect the knight in shining armor to come in and rescue you,” says Marcel Rodriguez. “If you’re going to be rescued, it’s going to be by your neighbors.” Rodriguez, a 47-year-old mergers and acquisitions specialist, joined the Riverdale–Tryon Creek Neighborhood Emergency Team (NET) a decade ago. Trained by the city-run program in basic first aid, fire suppression, rescue, and other handy skills, he and the 663 other local NET members covering 95 neighborhoods plan to offer cohesion amid chaos. Yet according to city emergency director Carmen Merlo, we still need more—way more. San Francisco, she points out, has 16,000 trained volunteers.

Anyone 14 or older can join a NET by completing an online training course of 17 introductory videos and undergoing a mandatory background check. Then comes a seven-session course, culminating in a four-hour exercise in the field. There is also an intensive version, given in three, all-day Saturday sessions.

“We don’t need everyone to be a ‘doomsday prepper,’” says Rodriguez. “Just tackle the small scale: make sure your family is safe, then your neighbors, then your neighbors’ neighbors, and go from there. Having a basic plan and some basic skills gets you a foothold.”

7. And, er, this tsunami?

The Japanese earthquake in 2011 generated tsunami waves up to 132 feet high, washing over areas in which nearly 300,000 people lived. The Northwest’s wave will be comparatively shallow at up to 30–40 feet. But the 22,000 full-time residents who live in the areas the tsunami will flood—plus tourists—will have just 15–20 minutes to get themselves to higher ground. Consider Seaside, where 83 percent of the population and almost 100 percent of the city’s critical facilities are in the tsunami zone. (The state geology department offers a trove of maps and other information.) For people in the inundation zone, any possessions not on their backs (or in storage outside the flooded zone) will be gone. And, thanks to crumbling bridges and landslides, they will be cut off from the east side of the Coast Range for weeks—maybe months.

In other words, if you’re on the coast when the Big One hits, your stay may prove longer than you planned.

What we've done: Waldport, Lincoln County, Cannon Beach, and Seaside are laying plans to move schools. Between 2000 and 2010, more than 50 percent of growth in coastal communities has been outside of the tsunami zone.

What we should do: Relocate all of the coast’s critical facilities outside the tsunami zone and make at least some of them tsunami-resistant. Use hotel room–tax funding to bankroll education campaigns and evacuation plans for tourists. And for you weekenders: pack a lightweight survival kit for your next coastal vacation.