Cascadia's Fault (44 page)

Another reason to study steel was that the Northridge jolt of 1994 had shown scientists that brittle welds in older steel-frame buildings had failed more often than anyone had expected. Amendments to the building code made in the wake of Northridge have changed the way structural joints are welded, presumably giving newer buildings extra strength. And Yang's model did seem to confirm that newer towers would be stronger—but only up to a point.

If the rupture of Cascadia's fault happens to extend down below the west coast beaches to some point underneath the Olympic Mountains—closer to Seattle—the shaking would be much worse. And when that scenario was run in the Caltech simulation,
all
the high-rise buildings in Yang and Heaton's experimental model
collapsed.
Even those with “perfect welds.”

Some of the science writers saw parallels to Mexico City and wanted to know more. “All the crummy little buildings that existed in Mexico City were completely undamaged,” Heaton explained, offhandedly, to one reporter, “but the high-rise buildings, which were the pride of their construction industry, many of them collapsed. It wasn't just a matter of poor construction. It was a case of the wrong buildings being in the wrong place at the wrong time.”

Low-rise, low-tech buildings simply did not vibrate or resonate at the same frequency as the big shockwaves generated by a subduction zone. High-rise buildings, on the other hand—even relatively new ones—constructed on thick sedimentary soils, vibrated
more
than any engineer or any building code had anticipated. They shook to the point of collapse. And what happened in Mexico would presumably happen in Seattle, Vancouver, Victoria, and Portland as well, according to Heaton and Yang's research.

“In general, high-rise buildings behave very differently from low-rise buildings,” Heaton said. “They're primarily designed to be flexible. And in sharp, rapid shaking—during a
moderate
-size earthquake—high-rise buildings perform extremely well.” But a magnitude 9 was quite
obviously a different story. Yang told another reporter that there were approximately nine hundred high-rise towers within striking distance of Cascadia and half of those were built prior to 1994, when the new building code imposed tougher standards.

Reading between the lines, it was obvious to me that the number of tall buildings in danger would depend on how far “down-dip” Cascadia's fault slips when the Big One hits. If the locked part of the subduction zone—the part that will generate the shockwaves—extends farther inland than initially estimated, the impact on high-rise structures in big cities will be even more severe.

CHAPTER 24

Cascadia's Fault: Day of Reckoning

On a foggy spring morning just before sunrise, twenty-seven miles (43 km) northwest of Cape Mendocino, California, a pimple of rock roughly a dozen miles (19 km) below the ocean floor finally reaches its breaking point. On the same thrust fracture that rattled the towns of Petrolia, Ferndale, Eureka, and Arcata, two slabs of the earth's crust begin to slip and shudder and snap apart as Cascadia's fault finishes what it started back in 1992. That day could be only ten years away. Or two hundred years from now. Or it could happen tonight. And this is how I've imagined it will unfold.

The first jolt of stress coming out of the rocks sends a shockwave hurtling into northern California and southern Oregon like a thunderbolt—same as last time, only bigger. Ten times the magnitude and thirty-two times more energy. For a few stunned drivers on the back roads in the predawn gloom, the pulse of energy that tears through the ground looks dimly like a twenty-mile (30 km) wrinkle moving through a carpet of pastures and into thick stands of redwoods.

Telephone poles whip back and forth as if caught in a hurricane. Powerlines rip loose in a shower of blue and yellow sparks, falling to
the ground where they writhe like snakes, snapping and biting. Lights go out and the telephone system goes down.

Cornices fall, brick walls crack, plate glass shatters. Pavement buckles, cars and trucks veer into the ditch and into each other. A bridge across the Eel River is jerked off its foundations, collapsing into turbulent eddies below, taking a busload of farm workers with it. A gasoline tank truck swerves to miss a car that's made a panic stop in the middle of Main Street. The tanker bounces over a curb, taking down a lamppost, crashing sideways into a corner store. Seconds later the wreckage explodes. The fire will be difficult to fight because water pipes under the street are broken. People are awake now and screaming, running dazed and wounded into the streets.

Seeing fragments of this happen through drifting shrouds of fog makes it hard for survivors to know how much is real, how much is their worst nightmare. With computers crashing and cell towers dropping offline, all of Humboldt and Del Norte Counties in California are instantly cut off from the outside world, so nobody beyond the immediate area knows how bad it is here or how widespread the damage. Same for southern Oregon. Despite the rising sun everything suddenly seems dark again. People living in the necklace of towns and villages along the coast are now officially on their own. No help will be coming any time soon.

On a spit of sand running down the western edge of Humboldt Bay, an air raid siren wails as residents in the former sawmill town of Samoa, barely a dozen feet (3.6 m) above sea level, bang through their doors—those that will still open, that are not twisted out of true by the violent shaking of their homes—and run, walk, or stumble as best they can toward slightly higher ground near the water tower. They know from past drills that the first wave could hit the beach as quickly as eight minutes from the moment of rupture.

At the USGS lab in Menlo Park seismometers peg the quake at magnitude 8.1 and the tsunami detection centers in Alaska and Hawaii
begin waking up the alarm system with stand-by alerts all around the Pacific Rim. High-rise towers in Sacramento begin to sway. Early morning commuters emerging from a BART station in San Francisco feel the ground sway beneath their feet and immediately hit the sidewalk in a variety of awkward crouches, a familiar fear chilling their guts. Then another little rough spot on the bottom of the continent snaps off. The fault unzips some more.

Back in Petrolia, where the ground has been shaking for more than a minute already, the street now heaves like a trawler's greasy deck in a North Pacific gale. The entire Gorda plate has come unstuck. The outer edge of California snaps free like a steel spring in a juddering lurch—nine feet (2.7 m) to the west. The continental shelf heaves upward, lifting a mountain of seawater.

The new shockwave, from the latest broken rough spot, slams from the Gorda into the Juan de Fuca plate farther north—like gigantic train cars banging together—and thus the fault continues to rip all the way to Newport, Oregon, halfway up the state. The magnitude suddenly jumps to 8.6. A power surge blows a breaker somewhere east of town and feeds back through the system, throwing other breakers in a cascade of dominoes that quickly crashes the entire grid in Oregon, Washington, and parts of California, Idaho, and Nevada. A brownout begins in six more western states. The wireline phone systems crash in lockstep.

Then the asperity beneath Newport shears away. The fault unzips the rest of the way to Vancouver Island. The quake now pins seismic needles at magnitude 9.2. A pineapple express has delivered a long string of storms that are pelting rain from Cannon Beach all the way to the Queen Charlotte Islands. High-rise towers in Portland, Seattle, Vancouver, and Victoria begin to undulate. Cascadia's shockwave hammers through sandy soil, soft rock, and landfill like the deepest notes on a big string bass. The mushy ground sings harmony and tall buildings hum like so many tuning forks. The earth rings like a bell as three plates of crust find a new equilibrium.

On I-5, the main north–south interstate highway, thirty-seven bridges between Sacramento and Bellingham, Washington, collapse or are knocked off their pins. Five more go down between the Canada–U.S. border and downtown Vancouver. The most vital overland lifeline from California to British Columbia is severed and bleeding badly. The Trans-Canada Highway has been cut in three places east of Vancouver. All the big bridges spanning the Fraser River in metropolitan Vancouver, around Puget Sound in Seattle, and across the Columbia in Portland have been damaged. None has collapsed outright, but they are considered unsafe until inspection teams can check them out. All major highways leading out of the big cities are plugged with debris from toppled buildings, rockslides, and traffic jams.

Nineteen railway bridges along the north–south coastal mainline of the Burlington Northern Santa Fe railway are wrecked as well. Boulders block the east–west mainline tracks of both the Canadian Pacific and Canadian National railway systems. Three engines and twenty-nine chemical tank cars, at least half of them full of chlorine, derail and spill their deadly cargoes just outside Tacoma. Deep-sea shipping docks in Portland, Seattle, and Vancouver slump and crack, their pilings undermined by liquefaction. As miles and miles of dikes around the city of Richmond, British Columbia, turn to mush, the incoming tide sweeps inland, swamping much of the city.

The runways of every major coastal airport from northern California to Vancouver are buckled, cracked, and no longer flyable. An Airbus on short-final at Sea-Tac touches down just as the concrete breaks. The impact shears off the forward landing gear, causing the jet to belly skid for 120 yards (110 m) before bursting into flames. Dozens of other inbound flights now must find someplace else to land.

Sixteen emergency care hospitals in Vancouver, Victoria, Seattle, and Portland—many of them built before the latest earthquake codes came into effect—suffer full or partial failure of load-bearing walls. The oldest wing of St. Paul's Hospital in Vancouver collapses in a shower
of red bricks and dust. The wings that remain standing are only partly functional because the emergency power generators either don't kick in or are running at less than full capacity. More than 580 public school buildings that would have been used as triage and refugee evacuation centers have been badly damaged and are unsafe to enter. There was never enough money to reinforce them all in time.

After fifty cycles of harmonic vibration, dozens of tall buildings have shed most of their glass. In some downtown intersections the cascade of broken shards has piled up three feet deep. Whirling sheets and splinters of broken windowpanes sail down windy canyons, slicing and maiming and killing as they go. The tops of high-rise towers bang together like bull goats in rut.

Shockwaves have been pummeling the Pacific Northwest for four minutes and thirty-five seconds now and it still isn't over. After sixty-four cycles—skyscrapers swaying rhythmically from side to side in giddy wobbles—enough welds have cracked, enough concrete has spalled, enough shear walls have come unstuck that some towers begin to pancake. The same death spiral everyone saw in New York on 9/11 happens all over again. Smaller buildings, but more of them. Dozens go down in the four northern cities. Even as far south as Sacramento, damage to tall buildings is moderate to severe. Glass is falling and people are screaming down stairwells.

In all five major cities tens of thousands of people have been seriously injured. Hundreds, perhaps thousands, more are dead and all the coroners are quickly overwhelmed. But it's too soon to count bodies. More than a third of the oncoming shift of police, firefighters, paramedics, nurses, and doctors do not show up for work. They are either stranded by collapsed buildings, bridges, and roadways, injured or dead themselves, or sticking close to home to make sure their own families are okay before going to work. People who survive the collapses must do their own search and rescue for family members, friends, and neighbors still trapped in the rubble. Help will come eventually, but who knows when?

Tens of thousands of people gather in streets, schoolyards, and city parks, searching for safe ground, in dire need of relocation. Fright, confusion, and panic ripples through the huddled masses. Pets are running loose, barking mad, and there are reports of wild animals escaping from zoos. Looting has already begun and local authorities are quickly overwhelmed. The governors of Washington, Oregon, and California declare states of emergency and call the White House for federal backup. The National Guard is mobilized in all three states.

Canada has no national guard. A handful of coast guard and navy vessels from the Esquimalt base on Vancouver Island are getting mobilized, but most of the active army units are stationed back east or deployed overseas on peacekeeping or combat missions. The engineering battalion and all its equipment has been moved east of the Rockies in a budget-cutting exercise, so it will take many hours or perhaps days for heavy rescue teams to get past the landslides, wrecked bridges, and buckled runways.

When Canada's prime minister calls his good friend, the American president, the news is not encouraging. The United States is committed to several foreign war zones, so there are no heavy-lift transport planes or helicopters readily available to help in British Columbia. Every troop and every spare piece of equipment in operational condition has already been dispatched to Washington, Oregon, and California. All twenty-eight of America's urban rescue teams specially trained to save the lives of people buried under tons of twisted steel and concrete are fully engaged and too busy to help the Canadians. There are five such specialty teams in Canada, but with so many transport lifelines severed, it's going to be damned difficult to get them to the disaster zone in time.

The mountain of water lifted by more than eight hundred miles (1,300 km) of continental shelf suddenly heaving up has now collapsed under the force of gravity into a series of nine tsunami waves traveling east from the subduction zone toward North American shores and west across the Pacific at the speed of a jetliner. As predicted, the first swell
of angry seawater hits the beach at Samoa, California, only eight minutes after the earthquake began. Those who survived the devastating temblor but forgot the tsunami drill—or those who simply didn't hear the siren or couldn't move fast enough—are killed almost instantly, battered and drowned as their wood-frame homes now disintegrate and are swept off their foundations.