July 20, 2015 Issue
The Really Big One
An earthquake will destroy a sizable portion of the coastal Northwest. The question is when.
By Kathryn Schulz
When the 2011 earthquake and tsunami struck Tohoku, Japan, Chris Goldfinger was two hundred miles away, in the city of Kashiwa, at an international meeting on seismology. As the shaking started, everyone in the room began to laugh. Earthquakes are common in Japan—that one was the third of the week—and the participants were, after all, at a seismology conference. Then everyone in the room checked the time.
Seismologists
know that how long an earthquake lasts is a decent proxy for its
magnitude. The 1989 earthquake in Loma Prieta, California, which killed
sixty-three people and caused six billion dollars’ worth of damage,
lasted about fifteen seconds and had a magnitude of 6.9. A thirty-second
earthquake generally has a magnitude in the mid-sevens. A minute-long
quake is in the high sevens, a two-minute quake has entered the eights,
and a three-minute quake is in the high eights. By four minutes, an
earthquake has hit magnitude 9.0.
It
was March. There was a chill in the air, and snow flurries, but no snow
on the ground. Nor, from the feel of it, was there ground on the
ground. The earth snapped and popped and rippled. It was, Goldfinger
thought, like 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.
The quake passed the two-minute mark. The trees, still hung with the
previous autumn’s dead leaves, were making a strange rattling sound. The
flagpole atop the building he and his colleagues had just vacated was
whipping through an arc of forty degrees. The building itself was
base-isolated, a seismic-safety technology in which the body of a
structure rests on movable bearings rather than directly on its
foundation. Goldfinger lurched over to take a look. The base was
lurching, too, back and forth a foot at a time, digging a trench in the
yard. He thought better of it, and lurched away. His watch swept past
the three-minute mark and kept going.
Oh,
shit, Goldfinger thought, although not in dread, at first: in
amazement. For decades, seismologists had believed that Japan could not
experience an earthquake stronger than magnitude 8.4. In 2005, however,
at a conference in Hokudan, a Japanese geologist named Yasutaka Ikeda
had argued that the nation should expect a magnitude 9.0 in the near
future—with catastrophic consequences, because Japan’s famous
earthquake-and-tsunami preparedness, including the height of its sea
walls, was based on incorrect science. The presentation was met with
polite applause and thereafter largely ignored. Now, Goldfinger realized
as the shaking hit the four-minute mark, the planet was proving the
Japanese Cassandra right.
For
a moment, that was pretty cool: a real-time revolution in earthquake
science. Almost immediately, though, it became extremely uncool, because
Goldfinger and every other seismologist standing outside in Kashiwa
knew what was coming. One of them pulled out a cell phone and started
streaming videos from the Japanese broadcasting station NHK, shot by
helicopters that had flown out to sea soon after the shaking started.
Thirty minutes after Goldfinger first stepped outside, he watched the
tsunami roll in, in real time, on a two-inch screen.
In
the end, the magnitude-9.0 Tohoku earthquake and subsequent tsunami
killed more than eighteen thousand people, devastated northeast Japan,
triggered the meltdown at the Fukushima power plant, and cost an
estimated two hundred and twenty billion dollars. The shaking earlier in
the week turned out to be the foreshocks of the largest earthquake in
the nation’s recorded history. But for Chris Goldfinger, a
paleoseismologist at Oregon State University and one of the world’s
leading experts on a little-known fault line, the main quake was itself a
kind of foreshock: a preview of another earthquake still to come.
Most
people in the United States know just one fault line by name: the San
Andreas, which runs nearly the length of California and is perpetually
rumored to be on the verge of unleashing “the big one.” That rumor is
misleading, no matter what the San Andreas ever does. Every fault line
has an upper limit to its potency, determined by its length and width,
and by how far it can slip. For the San Andreas, one of the most
extensively studied and best understood fault lines in the world, that
upper limit is roughly an 8.2—a powerful earthquake, but, because the
Richter scale is logarithmic, only six per cent as strong as the 2011
event in Japan.
Take your
hands and hold them palms down, middle fingertips touching. Your right
hand represents the North American tectonic plate, which bears on its
back, among other things, our entire continent, from One World Trade
Center to the Space Needle, in Seattle. Your left hand represents an
oceanic plate called Juan de Fuca, ninety thousand square miles in size.
The place where they meet is the Cascadia subduction zone. Now slide
your left hand under your right one. That is what the Juan de Fuca plate
is doing: slipping steadily beneath North America. When you try it,
your right hand will slide up your left arm, as if you were pushing up
your sleeve. That is what North America is not doing. It is stuck,
wedged tight against the surface of the other plate.
Flick your right fingers
outward, forcefully, so that your hand flattens back down again. When
the next very big earthquake hits, the northwest edge of the continent,
from California to Canada and the continental shelf to the Cascades,
will drop by as much as six feet and rebound thirty to a hundred feet to
the west—losing, within minutes, all the elevation and compression it
has gained over centuries. Some of that shift will take place beneath
the ocean, displacing a colossal quantity of seawater. (Watch what your
fingertips do when you flatten your hand.) The water will surge upward
into a huge hill, then promptly collapse. One side will rush west,
toward Japan. The other side will rush east, in a seven-hundred-mile
liquid wall that will reach the Northwest coast, on average, fifteen
minutes after the earthquake begins. By the time the shaking has ceased
and the tsunami has receded, the region will be unrecognizable. Kenneth
Murphy, who directs FEMA’s Region X, the division
responsible for Oregon, Washington, Idaho, and Alaska, says, “Our
operating assumption is that everything west of Interstate 5 will be
toast.”
In the Pacific Northwest, the area of impact will cover*
some hundred and forty thousand square miles, including Seattle,
Tacoma, Portland, Eugene, Salem (the capital city of Oregon), Olympia
(the capital of Washington), and some seven million people. When the
next full-margin rupture happens, that region will suffer the worst
natural disaster in the history of North America. Roughly three thousand
people died in San Francisco’s 1906 earthquake. Almost two thousand
died in Hurricane Katrina. Almost three hundred died in Hurricane Sandy.
FEMA projects that nearly thirteen thousand people will
die in the Cascadia earthquake and tsunami. Another twenty-seven
thousand will be injured, and the agency expects that it will need to
provide shelter for a million displaced people, and food and water for
another two and a half million. “This is one time that I’m hoping all
the science is wrong, and it won’t happen for another thousand years,”
Murphy says.
In
May of 1804, Meriwether Lewis and William Clark, together with their
Corps of Discovery, set off from St. Louis on America’s first official
cross-country expedition. Eighteen months later, they reached the
Pacific Ocean and made camp near the present-day town of Astoria,
Oregon. The United States was, at the time, twenty-nine years old.
Canada was not yet a country. The continent’s far expanses were so
unknown to its white explorers that Thomas Jefferson, who commissioned
the journey, thought that the men would come across woolly mammoths.
Native Americans had lived in the Northwest for millennia, but they had
no written language, and the many things to which the arriving Europeans
subjected them did not include seismological inquiries. The newcomers
took the land they encountered at face value, and at face value it was a
find: vast, cheap, temperate, fertile, and, to all appearances,
remarkably benign.
A
century and a half elapsed before anyone had any inkling that the
Pacific Northwest was not a quiet place but a place in a long period of
quiet. It took another fifty years to uncover and interpret the region’s
seismic history. Geology, as even geologists will tell you, is not
normally the sexiest of disciplines; it hunkers down with earthly stuff
while the glory accrues to the human and the cosmic—to genetics,
neuroscience, physics. But, sooner or later, every field has its field
day, and the discovery of the Cascadia subduction zone stands as one of
the greatest scientific detective stories of our time.
The Pacific
Northwest sits squarely within the Ring of Fire. Off its coast, an
oceanic plate is slipping beneath a continental one. Inland, the Cascade
volcanoes mark the line where, far below, the Juan de Fuca plate is
heating up and melting everything above it. In other words, the Cascadia
subduction zone has, as Goldfinger put it, “all the right anatomical
parts.” Yet not once in recorded history has it caused a major
earthquake—or, for that matter, any quake to speak of. By contrast,
other subduction zones produce major earthquakes occasionally and minor
ones all the time: magnitude 5.0, magnitude 4.0, magnitude why are the
neighbors moving their sofa at midnight. You can scarcely spend a week
in Japan without feeling this sort of earthquake. You can spend a
lifetime in many parts of the Northwest—several, in fact, if you had
them to spend—and not feel so much as a quiver. The question facing
geologists in the nineteen-seventies was whether the Cascadia subduction
zone had ever broken its eerie silence.
In
the late nineteen-eighties, Brian Atwater, a geologist with the United
States Geological Survey, and a graduate student named David Yamaguchi
found the answer, and another major clue in the Cascadia puzzle. Their
discovery is best illustrated in a place called the ghost forest, a
grove of western red cedars on the banks of the Copalis River, near the
Washington coast. When I paddled out to it last summer, with Atwater and
Yamaguchi, it was easy to see how it got its name. The cedars are
spread out across a low salt marsh on a wide northern bend in the river,
long dead but still standing. Leafless, branchless, barkless, they are
reduced to their trunks and worn to a smooth silver-gray, as if they had
always carried their own tombstones inside them.
What
killed the trees in the ghost forest was saltwater. It had long been
assumed that they died slowly, as the sea level around them gradually
rose and submerged their roots. But, by 1987, Atwater, who had found in
soil layers evidence of sudden land subsidence along the Washington
coast, suspected that that was backward—that the trees had died quickly
when the ground beneath them plummeted. To find out, he teamed up with
Yamaguchi, a specialist in dendrochronology, the study of growth-ring
patterns in trees. Yamaguchi took samples of the cedars and found that
they had died simultaneously: in tree after tree, the final rings dated
to the summer of 1699. Since trees do not grow in the winter, he and
Atwater concluded that sometime between August of 1699 and May of 1700
an earthquake had caused the land to drop and killed the cedars. That
time frame predated by more than a hundred years the written history of
the Pacific Northwest—and so, by rights, the detective story should have
ended there.
But
it did not. If you travel five thousand miles due west from the ghost
forest, you reach the northeast coast of Japan. As the events of 2011
made clear, that coast is vulnerable to tsunamis, and the Japanese have
kept track of them since at least 599 A.D. In that fourteen-hundred-year
history, one incident has long stood out for its strangeness. On the
eighth day of the twelfth month of the twelfth year of the Genroku era, a
six-hundred-mile-long wave struck the coast, levelling homes, breaching
a castle moat, and causing an accident at sea. The Japanese understood
that tsunamis were the result of earthquakes, yet no one felt the ground
shake before the Genroku event. The wave had no discernible origin.
When scientists began studying it, they called it an orphan tsunami.
Finally, in a 1996 article in Nature,
a seismologist named Kenji Satake and three colleagues, drawing on the
work of Atwater and Yamaguchi, matched that orphan to its parent—and
thereby filled in the blanks in the Cascadia story with uncanny
specificity. At approximately nine o’ clock at night on January 26,
1700, a magnitude-9.0 earthquake struck the Pacific Northwest, causing
sudden land subsidence, drowning coastal forests, and, out in the ocean,
lifting up a wave half the length of a continent. It took roughly
fifteen minutes for the Eastern half of that wave to strike the
Northwest coast. It took ten hours for the other half to cross the
ocean. It reached Japan on January 27, 1700: by the local calendar, the
eighth day of the twelfth month of the twelfth year of Genroku.
Once
scientists had reconstructed the 1700 earthquake, certain previously
overlooked accounts also came to seem like clues. In 1964, Chief Louis
Nookmis, of the Huu-ay-aht First Nation, in British Columbia, told a
story, passed down through seven generations, about the eradication of
Vancouver Island’s Pachena Bay people. “I think it was at nighttime that
the land shook,” Nookmis recalled. According to another tribal history,
“They sank at once, were all drowned; not one survived.” A hundred
years earlier, Billy Balch, a leader of the Makah tribe, recounted a
similar story. Before his own time, he said, all the water had receded
from Washington State’s Neah Bay, then suddenly poured back in,
inundating the entire region. Those who survived later found canoes
hanging from the trees. In a 2005 study, Ruth Ludwin, then a
seismologist at the University of Washington, together with nine
colleagues, collected and analyzed Native American reports of
earthquakes and saltwater floods. Some of those reports contained enough
information to estimate a date range for the events they described. On
average, the midpoint of that range was 1701.
Goldfinger
told me this in his lab at Oregon State, a low prefab building that a
passing English major might reasonably mistake for the maintenance
department. Inside the lab is a walk-in freezer. Inside the freezer are
floor-to-ceiling racks filled with cryptically labelled tubes, four
inches in diameter and five feet long. Each tube contains a core sample
of the seafloor. Each sample contains the history, written in
seafloorese, of the past ten thousand years. During subduction-zone
earthquakes, torrents of land rush off the continental slope, leaving a
permanent deposit on the bottom of the ocean. By counting the number and
the size of deposits in each sample, then comparing their extent and
consistency along the length of the Cascadia subduction zone, Goldfinger
and his colleagues were able to determine how much of the zone has
ruptured, how often, and how drastically.
Thanks
to that work, we now know that the Pacific Northwest has experienced
forty-one subduction-zone earthquakes in the past ten thousand years. If
you divide ten thousand by forty-one, you get two hundred and
forty-three, which is Cascadia’s recurrence interval: the average amount
of time that elapses between earthquakes. That timespan is dangerous
both because it is too long—long enough for us to unwittingly build an
entire civilization on top of our continent’s worst fault line—and
because it is not long enough. Counting from the earthquake of 1700, we
are now three hundred and fifteen years into a
two-hundred-and-forty-three-year cycle.
It
is possible to quibble with that number. Recurrence intervals are
averages, and averages are tricky: ten is the average of nine and
eleven, but also of eighteen and two. It is not possible, however, to
dispute the scale of the problem. The devastation in Japan in 2011 was
the result of a discrepancy between what the best science predicted and
what the region was prepared to withstand. The same will hold true in
the Pacific Northwest—but here the discrepancy is enormous. “The science
part is fun,” Goldfinger says. “And I love doing it. But the gap
between what we know and what we should do about it is getting bigger
and bigger, and the action really needs to turn to responding.
Otherwise, we’re going to be hammered. I’ve been through one of these
massive earthquakes in the most seismically prepared nation on earth. If
that was Portland”—Goldfinger finished the sentence with a shake of his
head before he finished it with words. “Let’s just say I would rather
not be here.”
The
first sign that the Cascadia earthquake has begun will be a
compressional wave, radiating outward from the fault line. Compressional
waves are fast-moving, high-frequency waves, audible to dogs and
certain other animals but experienced by humans only as a sudden jolt.
They are not very harmful, but they are potentially very useful, since
they travel fast enough to be detected by sensors thirty to ninety
seconds ahead of other seismic waves. That is enough time for earthquake
early-warning systems, such as those in use throughout Japan, to
automatically perform a variety of lifesaving functions: shutting down
railways and power plants, opening elevators and firehouse doors,
alerting hospitals to halt surgeries, and triggering alarms so that the
general public can take cover. The Pacific Northwest has no
early-warning system. When the Cascadia earthquake begins, there will
be, instead, a cacophony of barking dogs and a long, suspended,
what-was-that moment before the surface waves arrive. Surface waves are
slower, lower-frequency waves that move the ground both up and down and
side to side: the shaking, starting in earnest.
Soon
after that shaking begins, the electrical grid will fail, likely
everywhere west of the Cascades and possibly well beyond. If it happens
at night, the ensuing catastrophe will unfold in darkness. In theory,
those who are at home when it hits should be safest; it is easy and
relatively inexpensive to seismically safeguard a private dwelling. But,
lulled into nonchalance by their seemingly benign environment, most
people in the Pacific Northwest have not done so. That nonchalance will
shatter instantly. So will everything made of glass. Anything indoors
and unsecured will lurch across the floor or come crashing down:
bookshelves, lamps, computers, cannisters of flour in the pantry.
Refrigerators will walk out of kitchens, unplugging themselves and
toppling over. Water heaters will fall and smash interior gas lines.
Houses that are not bolted to their foundations will slide off—or,
rather, they will stay put, obeying inertia, while the foundations,
together with the rest of the Northwest, jolt westward. Unmoored on the
undulating ground, the homes will begin to collapse.
Across
the region, other, larger structures will also start to fail. Until
1974, the state of Oregon had no seismic code, and few places in the
Pacific Northwest had one appropriate to a magnitude-9.0 earthquake
until 1994. The vast majority of buildings in the region were
constructed before then. Ian Madin, who directs the Oregon Department of
Geology and Mineral Industries (DOGAMI), estimates that seventy-five per cent of all structures in the state are not designed to withstand a major Cascadia quake. FEMA
calculates that, across the region, something on the order of a million
buildings—more than three thousand of them schools—will collapse or be
compromised in the earthquake. So will half of all highway bridges,
fifteen of the seventeen bridges spanning Portland’s two rivers, and
two-thirds of railways and airports; also, one-third of all fire
stations, half of all police stations, and two-thirds of all hospitals.
Among
natural disasters, tsunamis may be the closest to being completely
unsurvivable. The only likely way to outlive one is not to be there when
it happens: to steer clear of the vulnerable area in the first place,
or get yourself to high ground as fast as possible. For the seventy-one
thousand people who live in Cascadia’s inundation zone, that will mean
evacuating in the narrow window after one disaster ends and before
another begins. They will be notified to do so only by the earthquake
itself—“a vibrate-alert system,” Kevin Cupples, the city planner for the
town of Seaside, Oregon, jokes—and they are urged to leave on foot,
since the earthquake will render roads impassable. Depending on
location, they will have between ten and thirty minutes to get out. That
time line does not allow for finding a flashlight, tending to an
earthquake injury, hesitating amid the ruins of a home, searching for
loved ones, or being a Good Samaritan. “When that tsunami is coming, you
run,” Jay Wilson, the chair of the Oregon Seismic Safety Policy
Advisory Commission (OSSPAC), says. “You protect yourself, you don’t turn around, you don’t go back to save anybody. You run for your life.”
These lax safety
policies guarantee that many people inside the inundation zone will not
get out. Twenty-two per cent of Oregon’s coastal population is
sixty-five or older. Twenty-nine per cent of the state’s population is
disabled, and that figure rises in many coastal counties. “We can’t save
them,” Kevin Cupples says. “I’m not going to sugarcoat it and say, ‘Oh,
yeah, we’ll go around and check on the elderly.’ No. We won’t.” Nor
will anyone save the tourists. Washington State Park properties within
the inundation zone see an average of seventeen thousand and twenty-nine
guests a day. Madin estimates that up to a hundred and fifty thousand
people visit Oregon’s beaches on summer weekends. “Most of them won’t
have a clue as to how to evacuate,” he says. “And the beaches are the
hardest place to evacuate from.”
Those
who cannot get out of the inundation zone under their own power will
quickly be overtaken by a greater one. A grown man is knocked over by
ankle-deep water moving at 6.7 miles an hour. The tsunami will be moving
more than twice that fast when it arrives. Its height will vary with
the contours of the coast, from twenty feet to more than a hundred feet.
It will not look like a Hokusai-style wave, rising up from the surface
of the sea and breaking from above. It will look like the whole ocean,
elevated, overtaking land. Nor will it be made only of water—not once it
reaches the shore. It will be a five-story deluge of pickup trucks and
doorframes and cinder blocks and fishing boats and utility poles and
everything else that once constituted the coastal towns of the Pacific
Northwest.
To
see the full scale of the devastation when that tsunami recedes, you
would need to be in the international space station. The inundation zone
will be scoured of structures from California to Canada. The earthquake
will have wrought its worst havoc west of the Cascades but caused
damage as far away as Sacramento, California—as distant from the
worst-hit areas as Fort Wayne, Indiana, is from New York. FEMA expects
to coördinate search-and-rescue operations across a hundred thousand
square miles and in the waters off four hundred and fifty-three miles of
coastline. As for casualties: the figures I cited earlier—twenty-seven
thousand injured, almost thirteen thousand dead—are based on the
agency’s official planning scenario, which has the earthquake striking
at 9:41 A.M. on February 6th. If, instead, it strikes in
the summer, when the beaches are full, those numbers could be off by a
horrifying margin.
How much all this will cost is anyone’s guess; FEMA
puts every number on its relief-and-recovery plan except a price. But
whatever the ultimate figure—and even though U.S. taxpayers will cover
seventy-five to a hundred per cent of the damage, as happens in declared
disasters—the economy of the Pacific Northwest will collapse. Crippled
by a lack of basic services, businesses will fail or move away. Many
residents will flee as well. OSSPAC predicts a
mass-displacement event and a long-term population downturn. Chris
Goldfinger didn’t want to be there when it happened. But, by many
metrics, it will be as bad or worse to be there afterward.
On
the face of it, earthquakes seem to present us with problems of space:
the way we live along fault lines, in brick buildings, in homes made
valuable by their proximity to the sea. But, covertly, they also present
us with problems of time. The earth is 4.5 billion years old, but we
are a young species, relatively speaking, with an average individual
allotment of three score years and ten. The brevity of our lives breeds a
kind of temporal parochialism—an ignorance of or an indifference to
those planetary gears which turn more slowly than our own.
This
problem is bidirectional. The Cascadia subduction zone remained hidden
from us for so long because we could not see deep enough into the past.
It poses a danger to us today because we have not thought deeply enough
about the future. That is no longer a problem of information; we now
understand very well what the Cascadia fault line will someday do. Nor
is it a problem of imagination. If you are so inclined, you can watch an
earthquake destroy much of the West Coast this summer in Brad Peyton’s
“San Andreas,” while, in neighboring theatres, the world threatens to
succumb to Armageddon by other means: viruses, robots, resource
scarcity, zombies, aliens, plague. As those movies attest, we excel at
imagining future scenarios, including awful ones. But such apocalyptic
visions are a form of escapism, not a moral summons, and still less a
plan of action. Where we stumble is in conjuring up grim futures in a
way that helps to avert them.
The
last person I met with in the Pacific Northwest was Doug Dougherty, the
superintendent of schools for Seaside, which lies almost entirely
within the tsunami-inundation zone. Of the four schools that Dougherty
oversees, with a total student population of sixteen hundred, one is
relatively safe. The others sit five to fifteen feet above sea level.
When the tsunami comes, they will be as much as forty-five feet below
it.
In 2009, Dougherty told me, he
found some land for sale outside the inundation zone, and proposed
building a new K-12 campus there. Four years later, to foot the
hundred-and-twenty-eight-million-dollar bill, the district put up a bond
measure. The tax increase for residents amounted to two dollars and
sixteen cents per thousand dollars of property value. The measure failed
by sixty-two per cent. Dougherty tried seeking help from Oregon’s
congressional delegation but came up empty. The state makes money
available for seismic upgrades, but buildings within the inundation zone
cannot apply. At present, all Dougherty can do is make sure that his
students know how to evacuate.
Some
of them, however, will not be able to do so. At an elementary school in
the community of Gearhart, the children will be trapped. “They can’t
make it out from that school,” Dougherty said. “They have no place to
go.” On one side lies the ocean; on the other, a wide, roadless bog.
When the tsunami comes, the only place to go in Gearhart is a small
ridge just behind the school. At its tallest, it is forty-five feet
high—lower than the expected wave in a full-margin earthquake. For now,
the route to the ridge is marked by signs that say “Temporary Tsunami
Assembly Area.” I asked Dougherty about the state’s long-range plan.
“There is no long-range plan,” he said.
Dougherty’s
office is deep inside the inundation zone, a few blocks from the beach.
All day long, just out of sight, the ocean rises up and collapses,
spilling foamy overlapping ovals onto the shore. Eighty miles farther
out, ten thousand feet below the surface of the sea, the hand of a
geological clock is somewhere in its slow sweep. All across the region,
seismologists are looking at their watches, wondering how long we have,
and what we will do, before geological time catches up to our own. ♦
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