Full-Rip 9.0: The Next Big Earthquake in the Pacific Northwest

by Sandi Doughton

  “I first found this place in 1987,” he said, leaning on his paddle to round the Grumman through a broad curve in the river. A spectral scene appeared in the distance. Towering trunks of long-dead cedars, bleached white as bone, stood sentinel in a meadow fringed with spruce.

  “The ghost forest of the Copalis.” Atwater said.

  Atwater beached the canoe and scrambled up the bank onto ground thick with huckleberry, salal, and sharp-bladed grass. Channels that fill with brackish water when the tide is high snaked among the spongy hassocks. The marsh had the feel of an old battlefield—hushed now, but the battered trunks testifying to great violence in the part.

  It hit suddenly, Atwater explained. During the last great earthquake, this riverfront forest shuddered and dropped. Trees that took root during the Middle Ages drowned, their roots suddenly submerged. The trunks were still upright after so long only because cedar is resistant to rot.

  When he first saw those ghosts, Atwater didn’t know what to make of them. He had seen roots of Sitka spruce in buried marshes along with silverweed and other plants. But the tree trunks had rotted away long ago. “I was confused by standing trees,” he recalled, circling a dead giant that measured six feet across. It was David Yamaguchi, the forester, who helped figure out what those silent witnesses could say about the upheaval that claimed their lives.

  The two researchers had met by chance when Atwater presented a lunchtime seminar at Mount St. Helens. In the wake of its colossal outburst, the volcano was swarming with “more scientists than flies on bear turds,” Yamaguchi recalled. He was the one who didn’t fit in, a chatty biologist surrounded by geologists who preferred the company of rocks. The USGS hired him on a temporary basis because his knack for tree rings turned out to be useful. By analyzing forests killed or damaged in previous eruptions, Yamaguchi was able to fill in some of the blanks in the volcano’s eruptive history.

  In the field he peppered the geologists with questions: What did they see when they looked at the landscape? How could they tell one type of lava flow from another? In return he taught them how to distinguish hemlock from fir and how to read the vegetation for clues about the underlying soil and rock.

  As he munched his sandwich and listened to Atwater bemoan his mushy carbon dates, Yamaguchi raised his hand.

  “I know someone who can help you,” he said.

  “Who?” Atwater asked.

  “Me.”

  Tree-ring dating works best in places like the desert Southwest, where it was developed. Wide seasonal swings in rainfall create ring-width patterns so varied and crisp they pop out to the naked eye. Dendrochronologists have a harder time of it in the Pacific Northwest, where one year is just as soggy as the next. Worst of all are the coastal rain forests, where nature delivers up to 170 inches of precipitation a year and timber grows faster than anywhere else in the world.

  “The happier trees are, the less distinctive their ring patterns,” Yamaguchi explained. Despite his confident declaration, he wasn’t sure he could use trees to figure out when the last megaquake struck.

  Yamaguchi’s first visit to the ghost forest raised his hopes. A fresh cedar aroma wafted into the air as his chain saw bit into the trunks. He sliced out pie-shaped wedges. The bark was gone and the outer rings rubbed away by time and weather. But the interior patterns were clear and varied. “That was exciting,” Yamaguchi recalled. “If the rings had been uniform, I didn’t have a chance.”

  That’s because counting rings in the ghost cedars alone couldn’t tell him when the latest earthquake hit. He had no way of knowing which ring corresponded to which year. What Yamaguchi needed were reference sequences from trees where the date of death was known. The reference cedars had to come from the same neck of the Northwest woods, because trees that experience similar weather patterns will have similar ring patterns: wide during wet years, skinny during years with less rainfall. The patterns are like bar codes. If Yamaguchi could find good reference trees, he could compare their bar codes to those in the quake-killed cedars and look for overlapping sequences. That would allow him to anchor the ghost forest in time and zero in on the trees’ final years of life.

  But in the late-1980s, old-growth cedars along the Washington coast were as rare as spotted owls. Lowland forests were the first to fall in the logging frenzy that gathered steam after World War I and continued chugging for seven decades. Museums had cross-sections of some of the grandfather trees, but getting permission to work with them and verify the dates would be tough. It was Yamaguchi’s turn for a stroke of luck.

  BAR CODE

  Scientists compared the bar code–like ring sequences from trees that survived the last Cascadia megaquake with trees killed by the quake to estimate an approximate date. (image credits 2.4)

  In the summer of 1987, he and Atwater drove the region’s back roads and paddled streams in search of more ghost forests. One day the scientists spotted a scene that looked like something from the heyday of the timber barons. On a tiny island at the south end of Willapa Bay, Weyerhaeuser was felling Western red cedars so big a single tree filled a log truck. The stand had dodged destruction for so long because of its location. “They cut every toothpick on the mainland,” Yamaguchi said, “but it was just enough of a hassle to get to the island that they left it alone.”

  The trees were coming down as part of a timber-for-land swap between the logging company and the federal government, which wanted to turn the island into a wildlife refuge. The stumps would be perfect for Yamaguchi’s purposes. Easily more than 600 years old, the trees had weathered the last earthquake—and there was no doubt about the year of their demise. He could see them being felled.

  The loggers started work at dawn, toppling the giants and loading them onto a barge for the short trip across the water. Like burglars, Yamaguchi and his assistant waited until the crew knocked off at 2:00 PM, then paddled over in his canoe. “We could have asked for permission,” he said, with a laugh, “but maybe they would have said no.” On the island, Yamaguchi fired up his chain saw and carved long, thin sections from stumps wide enough to park a car on. He piled the wood in the center of the canoe and paddled back to the mainland. Yamaguchi made surreptitious trips to the island over several days. On some of the return legs, the canoe was so loaded it barely cleared the water.

  Yamaguchi sanded the specimens to a high gloss. In November, he loaded them into the back of his old station wagon and drove to Seattle to spend Thanksgiving with his parents. The University of Washington, where he earned his doctorate, had a dendrochronology lab. For a week, he cranked tree sections through a boxy microscope, measuring the width of every ring. It was impossible to match patterns by eye, so he wrote a rudimentary program to tap the power of early microcomputers.

  “Pretty quickly, I could see it was going to work.”

  With growing excitement Yamaguchi zeroed in on dates. There was still uncertainty in the numbers because the outer rings were missing from the ghost forest cedars. But it was clear the trees had lived through the 1680s. Whatever killed them struck after that—and before white settlers arrived.

  While Yamaguchi was poring over wood slices, Atwater was pushing radiocarbon methods as hard as he could. High-precision techniques pioneered at the University of Washington narrowed the window for the last Cascadia quake to sometime between 1680 and 1720, at least five decades before European explorers laid eyes on the Washington coast. If those dates were right, the subduction zone had been building up pressure for about three hundred years. Did that mean it might be near the breaking point?

  Atwater applied the high-precision dating to all of his buried soil layers, each representing a megaquake. The average interval between them was about five hundred years. The shortest was a scant two hundred.

  Before winding up his field trip on the Copalis in May 2011, Atwater submitted to a television interview with the ghost forest as a backdrop. Japan’s recent killer quake and tsunami were a mirror image of what the Northwest can expect, and the media
had been clamoring for Atwater’s expertise. The guy who was turned away from an earthquake workshop a quarter of a century ago was now, at age sixty, a global authority.

  Atwater’s wife, Frances, said her husband never wanted to be in the public eye or play the role of expert. “He just saw what needed to be done and he did it.” Atwater will talk to journalists, community groups, park rangers, engineers—anyone who wants to be better informed and better prepared for what Cascadia has in store. That’s why he devoted a spring day to paddling a stretch of the Copalis he’s visited more than a hundred times.

  By the early 1990s, scientific skepticism had vanished under the weight of the evidence Atwater and other teams of geologists kept piling on. But the scientists still couldn’t say whether the most recent quake had been a full-rip 9. The carbon dates from buried soil layers weren’t good enough to rule out a series of smaller quakes in quick succession.

  A bout with Hodgkin’s lymphoma—a kind of cancer that attacks the lymph nodes—gave Atwater a scare but didn’t slow his drive. “He would get chemo, be sick for three hours, then go back to work,” Frances said. After the 2004 Indian Ocean quake and tsunami, Atwater shifted his attention to developing nations that face the threat of megaquakes. He traveled to Indonesia for months at a time, collaborating with scientists there to learn more about the region’s seismic history. His latest focus is Pakistan, where the combination of a subduction zone and bad buildings puts millions of people at risk.

  His television interview over, Atwater took a last look at the ghost forest. In hopes of cashing in on a tourist boom that hasn’t come, the property owner built a dock that overlooks the site. Several of the trees fell in the past few years, and others are listing. “There are a lot fewer left than when we first came here,” Atwater said, a hint of regret in his voice.

  He herded the group back into their canoes for the trip downriver. Gauzy clouds muted the sun and the tide lapped up the riverbanks. Relaxed and smiling, Atwater paddled with the ease of a frontiersman. He misses the fieldwork, he admitted, the days governed by tides and capped off by discussions around the table in the old trailer. “It was fun seeing all the new country, all those early, misty mornings.”

  He hopes to get back to it soon, when his overseas work winds down. Unanswered questions about Cascadia nag at him. “There’s still a lot left to do here in the Northwest,” he said, dipping his paddle for the final push back to the launch site. Tonight he was headed to Hoquiam for a public meeting on tsunami risks. It would be midnight before he got home.

  CHAPTER 3:

  PARENT QUAKE, ORPHAN TSUNAMI

  WHEN JAMES GILCHRIST SWAN DIED in 1900, a delegation of Makah Indians paid their respects by making the 120-mile journey from Neah Bay to Port Townsend, a mill town near the mouth of Puget Sound. Arriving just before the casket was closed, they filed past, moaning in grief. “Each affectionately patted the face of the dead man,” the local paper reported.

  Swan was Massachusetts-born but found his true home when he settled on the Washington coast in 1852. Of all the places he rambled, he loved Neah Bay best. Swan visited the remote village often and lived among the Makah for four years. When he wasn’t plumbing a whiskey bottle, he taught school or doctored the sick. His voluminous journals described whale hunts, revenge killings, courtship customs—and a vanishing way of life. The writer Ivan Doig, who spun those journals into a book called Winter Brothers, admired Swan’s “rare knack of looking at the coastal Indians as flesh and blood, rather than the frontier’s tribal rubble.”

  Swan’s Makah friends told him stories never shared with white people before; unlike most whites, Swan listened. That’s how his diaries came to hold the first written account of a tsunami on the Northwest coast. The storyteller was Billy Balch, son of a chief and a tribal leader in his own right.

  “A long time ago, but not at a very remote period,” Balch told Swan, the Pacific Ocean receded for four days, leaving Neah Bay dry. The water surged back, rising for four days without any waves or breakers until everything was submerged but the mountaintops. “Many canoes came down in the trees and were destroyed, and numerous lives were lost.”

  Swan was skeptical of many Makah legends, but not this one. “There is no doubt in my mind of the truth of this tradition,” he wrote more than one hundred years before Atwater scraped at the banks of the Waatch River. “The Waatch prairie shows conclusively that the water of the Pacific once flowed through it,” Swan wrote, an observation based on his own spade work. “On cutting through the turf at any place … the whole substratum is found to be pure beach sand.”

  Despite its improbable eight-day timeline, Balch’s story also struck Tom Heaton and his USGS colleague Parke Snavely as credible. “The description of water receding from Neah Bay and then returning in a strong current is clearly suggestive of a tsunami,” they wrote in the first scientific paper to consider what the region’s original inhabitants had to say about its seismic past.

  Science and legend don’t often intersect. But since Heaton reached across the divide, researchers and tribal leaders have compiled dozens of stories of violent ground shaking, landslides, and ocean surges at sites from the rocky bays of British Columbia to California’s redwood forests. The stories leave little doubt that native people bore witness to the repeated geologic cataclysms recorded in Atwater’s mud layers. The first Northwesterners invoked the supernatural to explain the upheavals. Lacking written language they passed the knowledge on through story and song.

  And they would have been happy to talk about it sooner, if anyone had asked.

  “Hello?” said seventy-seven-year-old Viola Riebe of the Hoh Tribe on Washington’s Olympic coast. “We’ve been telling these stories for centuries.”

  Riebe’s uncle taught her about Thunderbird, who lives in the mountains at the headwaters of the Hoh River. The flapping of his mighty wings calls forth lightning and makes the earth move. In native stories from across the region, titanic battles between Thunderbird and his adversary, Whale, roil the sea and make the Earth tremble.

  As a young girl, Riebe was playing on the beach with her cousins one morning when the water started to pull away. “We could see all the rocks and boulders on the beach,” she said. “We didn’t know what was happening.” Steeped in tribal traditions, her uncle recognized the warning signs of a tsunami. “He was waving his hat and yelling at us to get off the beach.” In retrospect Riebe suspects the cause was a distant earthquake somewhere on the Pacific Rim. At the time she was relieved when a group of fishermen raced up in a truck to rescue the children as fast-rising water pinned them against a tangle of logs.

  “We learned a lesson that day,” Riebe said. “My uncle told us how a tidal wave like that had happened here a long time ago.”

  Former University of Washington seismologist Ruth Ludwin has combed through nineteenth-century ethnographies and talked with tribal elders in search of stories that might describe megaquakes and tsunamis. She wondered whether any of the accounts would converge in time with scientists’ discoveries of a giant quake about three centuries ago.

  Ludwin found the Northwest rich in earthquake legends. The Nuu-Chah-Nulth people of Vancouver Island blamed ground shaking on mountain dwarfs who would entice humans to join their dances. A mortal who stumbled into the wooden drum that kept the beat was cursed as an “earthquake man,” whose steps caused the ground to quiver. Ceremonies mirrored similar themes, with dancers shaking scallop-shell rattles or pounding drums filled with rocks to mimic the roar of trees and vibrating ground.

  Many stories packed moral lessons. Boys who killed crows or disrespected salmon called earthquakes down on their villages. Mistreated dogs took their revenge by howling up quakes that collapsed their masters’ houses. Other stories stressed preparedness: Warriors who braided ropes ahead of time were able to tether their canoes to trees and ride out the floods. Their lazy neighbors were swept away.

  Ludwin was particularly interested in stories that spoke of floods, stran
ge tides, or changes in ground level—features that distinguish subduction zone quakes and tsunamis from the run-of-the-mill shakes that strike more frequently.

  In a story reminiscent of Atwater’s buried marshes, the Yurok people of California’s redwood coast tell of Thunder and his rowdy companion Earthquake, who boasted, “I shall tear up the Earth.” The rampaging pair caused prairies to sink, allowing the sea to rush in and shellfish to flourish.

  The most spot-on account Ludwin found came from Washington’s Quileute tribe, now famous as the wolf-men of the Twilight vampire franchise. A chill prickled the back of her neck when she first read the legend of Thunderbird plucking Whale from the sea. “ ‘There was a shaking and a jumping up of the Earth beneath and a rolling up of the great waters.’ I thought, ‘Eureka!’ ”

  But extracting dates from mythic traditions can be harder than pinning a phantom to the wall. It wasn’t until the 1860s that anthropologists and settlers like Swan started recording the experiences of Northwest tribes. More than 150 years had passed since the last Cascadia megaquake, and tribal cultures were in tatters. Many groups were forced from their ancestral lands and decimated by disease. Smallpox ravaged the Makah. At the height of the epidemic one witness reported, “The beach at Neah Bay for a distance of eight miles was literally strewn with the dead bodies of these people.”

  Given the turmoil it’s amazing how many oral histories survived and astonishing that Ludwin and her collaborators were able to find nine stories—from the length of Cascadia—with enough detail to yield rough dates. “They’re not figurative,” she said. “These are stories of somebody who saw the flood or ancestors who experienced the flood.”

  Robert Dennis, a longtime leader of the Huu-ay-aht First Nation on Vancouver Island’s Barkley Sound, learned one of those stories from his great-grandfather. Chief Louis Nookmis, born in 1881, would sit Dennis and his brother down at the kitchen table and regale the boys with tribal history and lore. Some sessions stretched on for hours, an eternity for a twelve-year-old. “You couldn’t say, ‘I’m going outside to play,’ ” Dennis recalled.