Cascadia's Fault (41 page)

Vasily Titov extended the thought. “We cannot say when the next big earthquake is going to happen, but from the moment a tsunami is generated our models can actually tell you pretty well what happens next. How high the tsunami wave is going to be at the coastline, how
big the impact is going to be at a particular location. The only thing we have to know for that is the actual measurement of the tsunami wave.”

The success of the tsunami models, even though they're “never going to be perfect,” he said, “makes you feel that—gosh, all this mathematics that you learned in high school and the math at university can actually pay off and save lives. That's a pretty amazing feeling. Dry mathematics applied correctly—it can save lives.”

 

Chris Goldfinger, the marine geologist from Oregon State University, agreed with Titov. While still at sea off the coast of Sumatra, collecting mud-core samples in order to study how this earthquake happened, he couldn't avoid thinking of home. With a mud core sliced open on his laboratory workbench and the sea gently heaving beneath the hull of the
Roger Revelle,
Goldfinger drew the connection.

“I have to admit mud is not very exciting to look at. It just looks like some sand and some mud. But now every time I look at these cores, I see that giant breaking wave . . . It sort of brings home what these things really are,” he said. “Even though we work in the theory of all this, to actually
see
that for real was just stunning, and horrifying ... I think everyone's pretty mindful of the reason we're here,” he continued, with members of the Sumatra science team looking on, “and that maybe some of this research might help in some way.”

He paused for a moment and then tied the two stories together. “The same thing applies to Cascadia. I live there. And every time I drive to the coast, I see towns that are not long from now going to be under water from the next tsunami . . . The Cascadia Subduction Zone earthquake and the tsunami that'll come with it will be virtually identical to the one in 2004 in Sumatra. It'll dwarf 1906 [in San Francisco]. And Katrina. It'll be many
dozens
of Katrinas all at once. Coastal towns from northern California to Canada will be virtually wiped out. And there'll be significant damage in all the coastal
cities
along there as well—all at the same time.”

Goldfinger agreed that knowing what Cascadia's fault is capable of had utterly changed his perspective about living on the edge of a continent. “It's a little hard to go to the beach and just hang out there and enjoy it.”

Garry Rogers at the Geological Survey of Canada told me that what happened in Sumatra should have come as no surprise—and yet it did. “To all the scientists it was obvious that that's the kind of thing that happens,” Rogers said, matter-of-factly. “It was perhaps more severe in terms of death toll than most of us would have thought. But what it did, I think, to the general public—and what we tried to translate to the general public—is that
Sumatra is Cascadia.
Those zones are the same size; what happened in Sumatra is what happened in Cascadia in 1700, and many times before that.”

Now Rogers' voice was rising. “That's what we're talking about,
big
shaking. It damages a
lot
of buildings. And then a tsunami comes in on the shore. And we need to be able as a society to deal with that situation.”

CHAPTER 22

The Next Wave: Thinking the Unthinkable

To me the good news is that people living on the edge of North America are finally beginning to respond. Outport communities on the west coast are taking advantage of new flood maps that show how high up the beach Cascadia's wave is likely to reach, what parts of town will be inundated, and where the safe zones on high ground should be located. Tsunami evacuation routes have been mapped and signs posted. People are going to night classes to learn what they need to know in order to survive. Evacuation drills are being held. And in some cases schools, hospitals, and other vital public buildings are being reinforced or relocated.

Scientists from at least half a dozen universities in the United States and Canada are creating or updating numerical models that use detailed bathymetric maps of the local harbors and offshore terrain to predict much more precisely how far uphill and inland the turbulent muck is likely to travel. They're doing on a local level what Vasily Titov's model did on a global scale. Computer simulations of Cascadia's tsunami have been generated for the city of Victoria and for the fishing village of Ucluelet on the west coast of Vancouver Island, for Cannon Beach and Seaside on the Oregon coast, and dozens of others are in development.

Not every community in harm's way has a computer model to map the inundation zone. At least not yet. Some towns such as Port Alberni, which was hammered by the Alaska tsunami of 1964, don't have detailed bathymetric grids to work with because hydrographic survey ships are expensive to operate and government research budgets have been slashed. Rather than wait for public funding to catch up with grim reality, Port Alberni's emergency planning team took matters into their own hands—literally.

Knowing from experience how waves coming in from the coast can get amplified by the narrow canyon walls of a fjord like the Alberni Inlet, local planners asked the experts at the Pacific Geoscience Centre for their best guess about the height of a seawater pulse coming from Cascadia's fault. Then they took out a standard topographic map of the downtown core along with a red marking pen.

Bob Harper, the head of emergency planning for the city of Port Alberni at the time, walked me through the exercise. “The best advice that we've received so far from the scientists is—because of the funneling effect in the Alberni Inlet—that we can expect somewhere in the twenty-meter range of inundation,” said Harper. “So that's twenty meters high . . . Not twenty meters in, but twenty meters up.”

“That means a sixty-foot wall of water?” I asked, trying to imagine the downtown waterfront.

“Yes,” he said quietly. A technician working with Harper began tracing the contour in bright red ink across the heart of downtown. “There's a band of residences along the riverside here,” his hand swept across the map following the contour around the harbor. It was clear that most of the central business district, all of the industrial waterfront, the pulp, paper, and lumber mills, would be inundated.

Cascadia's wave would be larger by far than anything seen in 1964, mainly because this subduction zone—birthplace of the tsunami—is so much closer to home. From the moment the ground begins to shake, places like Ucluelet and Tofino on the west side of Vancouver Island,
along with Cannon Beach and Seaside on the Oregon shore and the beaches of Pacific County, Washington, may have as little as fifteen minutes before the first wave makes landfall, with as many as eight or ten more en route behind it. And so the obvious question arises: what could or should a person standing on the beach do to survive? The logical answer is to head for higher ground. And do it right away.

 

I gave my stopwatch to Patrick Corcoran, who strapped it on his wrist and got ready to run. He stood only a few steps away from the wide, sandy beach at the base of the Lewis and Clark statue in the traffic circle at the western terminus of Broadway, the main drag in Seaside, Oregon. Young and fit, probably in his late thirties, Corcoran is a surfer by choice and an employee of Oregon State University by profession. As a “hazards outreach” specialist, he helps people along the coast plan for and come to terms with some of the realities of life on the edge—things like major winter storms, and getting ready for “the Big One” from Cascadia's fault.

Corcoran is demonstrating the official evacuation route, which begins at the beach promenade and follows Broadway, the main east–west business corridor, all the way across the downtown core to higher ground on the east side of town. As I give Corcoran the nod, he clicks the stopwatch and starts running.

In a real emergency, running or walking would probably be the only way to get out of town fast. Previous experience with tsunami false alarms in Seaside had already taught local residents that vehicle traffic hits gridlock almost immediately. It was a busy summer day so the sidewalk was crowded with shoppers and tourists out for a stroll. Corcoran jogged at a brisk pace, zigzagging through the throng.

The Pacific coastline here runs almost exactly north–south, so to get away from the ocean on the west side you have to move toward the first rank of low hills in the Coast Range mountains on the east. The city of Seaside is built on the wide, flat delta of the Necanicum River, so
anyone trying to outrun a tsunami would have to hustle to get across the two bridges that span branches of the river, hoping the earthquake and the incoming tsunami had not already knocked the concrete decks off their pilings.

By the time Corcoran got past the river and started uphill on a winding switchback road, he was breaking a sweat and breathing hard. He had covered more than twenty city blocks without gaining any altitude. Now the road started to climb steeply. He already knew from studying the map contours exactly which house he had to reach in order to get himself at least fifty feet (15 m) above sea level and presumably beyond the reach of the biggest waves likely to come from Cascadia's subduction zone.

When he crossed the imaginary finish line, he stopped and clicked the watch again. “So, seven minutes and thirty-three seconds,” he huffed. “Not too bad, but it was a hard run.” On a nice sunny day under ideal conditions, he certainly would have made it to high ground in plenty of time. But what if the earthquake happened on a stormy winter's night? Powerlines and trees would be down and all kinds of obstacles would be in the way.

And what about those not as young or physically fit as Patrick Corcoran? The likelihood that the vast majority of people could make that run before the first tsunami surge hit the beach seemed pretty slim to me. For those who hung around to
watch
the incoming waves, mesmerized by the spectacle as so many were on the beaches of Sumatra and Thailand, the chances of survival would be even less.

Corcoran has a set of simple guidelines he explains to anyone who will listen. Rule number one: if you're anywhere near the coast in a subduction zone and you feel the earth begin to shake, start moving to higher ground as soon as the shaking stops, or sooner if you can. Rule number two: if you're living in or visiting a coastal earthquake zone you should already know where the high, safe ground is and how to get there. Grab a map, study the evacuation routes, and always have a sense
of where you are. Rule number three: don't wait for a warning siren because there probably won't be one. Your only warning will be the violent shaking of the ground, so don't wait for someone in authority to tell you to run. Rule number four: if you stand there long enough to
see
the incoming tsunami, there's almost no chance you'll outrun it.

These are the kinds of things Corcoran recites when he does his outreach sessions. “When I came here in 2003 for the Coastal Storms Program,” he begins, “it was all about severe winter storms and flooding and those kind of more chronic or constantly occurring events. Then the 2004 Sumatran earthquake and tsunamis occurred, and while my
focus
was on storms, I had to ask myself as a coastal hazards agent, is this [tsunami threat] something that I should be paying attention to? And so I asked myself three questions: One, is it likely? Two, would it be bad? And three, can education do anything to improve the situation?”

In a heartbeat he answers his own questions: “Yes, yes, and Lord, I hope so. Yes it
is
likely. Yes it
would be
very bad. And education
will,
hopefully, go a long way towards improving the odds for most people.”

The first thing to know, according to Patrick Corcoran, is that if you hear a warning siren you shouldn't panic. It probably means there has been a distant temblor in Japan, Alaska, or Chile. “So if you heard a siren, or understood a tsunami was coming, and you didn't feel the earthquake, Alaska is the closest place it's going to be and that's three and a half to four hours away,” says Corcoran. “So the good news is—you have time before a small and not so bad tsunami comes.”

If it's a seismic jolt closer to home, the Big One from Cascadia's fault, the sirens won't have time to go off before the first wave gets here. That's because NOAA's warning buoys are anchored farther out in the Pacific—beyond the Cascadia Subduction Zone—in order to provide plenty of warning time for those long-distance waves from Japan, Alaska, and elsewhere. Cascadia's fault, being much closer to the shoreline of North America, will send out waves both east- and westbound. And the eastbound waves will hit the beaches of California, Oregon,
Washington, and British Columbia
at the same time as
or even before the westbound waves hit the warning buoys and trip the alarm. Until this chink in the armor of the tsunami warning system is dealt with by some newer generation of detectors closer to shore, the only real warning anyone in Cascadia will have is the violent shaking of the earth.

Corcoran begins to distil the to-do list. The first thing to figure out is whether the quake and tsunami are from far away or closer to home. Did you feel the earth move? Or was it a siren you heard? The implications are obvious and the necessary responses completely different.

“The second thing you need to know,” says Corcoran, “is where are the safer and less safe places. And not just where you live, but where you live, work, and play.” In other words, plan an evacuation route to safe ground from any place where you spend a considerable amount of time.

“Develop an eye for the landscape,” Corcoran suggests. “So, when the Big One occurs and we're out driving around conducting our lives, we'll have some sense of, ‘Wow, I'm in a bad spot. I need to get over there.' Or, ‘Wow, I'm in a good spot—relative to tsunamis—I'm gonna stay put.'