The Great Quake: How the Biggest Earthquake in North America Changed Our Understanding of the Planet

by Henry Fountain

  On the bill at the movies the coming week were Captains Courageous, with Spencer Tracy and Mickey Rooney, and The Big Knife, starring Jack Palance and Shelley Winters. Club Valdez, one of the town’s restaurants, advertised an Easter Sunday smorgasbord that included turkey and all the trimmings, as well as ham and baked beans, for three dollars. The Lions Club promoted its spring cleanup campaign. Chaperones were announced for an upcoming teen dance at the high school. The school’s chorus was to give a performance of the operetta Adventures of Tom Sawyer the following Saturday. “Don’t be surprised if you see a portable bush producing music,” the announcement read. “It is just our accompanist, Sally Huddleston.”

  And there, on page 7, was a brief announcement of the upcoming nuptials of Linda Gilbert, daughter of Kenneth Lee Gilbert of Lambertville, Michigan, to Gerald Zook, son of Mrs. William Zook of Valdez. The wedding was to take place on April 4 at 10 a.m. at St. Francis Xavier, with a reception for the young couple following the ceremony at the Switzerland Inn.

  Jerry Zook, age twenty-seven, had been born in Wrangell, Alaska. He’d served in the navy, and when he was discharged he’d moved to Valdez to be near his mother and stepfather. A good basketball player, he’d been recruited to play for the alumni that fall in Valdez High’s season opener. Somewhere along the line he’d fallen in love.

  An employee at the state highway department, he nonetheless was open to taking what extra work he could find, with the prospect of starting a family. On that Friday, eight days before his wedding, Jerry had gone down to the dock to help unload the Chena.

  Howard Ulrich maneuvered his forty-two-foot salmon troller, the Edrie, past the spit of land that marked the entrance to Lituya Bay and into the bay proper. It was about 8 p.m. on July 9, 1958, and Ulrich, who had his seven-year-old son, Howard Jr., with him, had decided to put in for the night. He had heard there was good fishing along this wild stretch of southeastern Alaskan coastline, 140 miles north of his home in Sitka. So he had bypassed more familiar trolling spots along the way. Ulrich figured he’d fish first thing in the morning; for now he and the boy, whom everyone called Sonny, would have supper and turn in early.

  Lituya Bay forms an indentation in a shoreline that features some of the highest coastal mountains anywhere in the world. The bay is about seven miles long and less than two miles across at its widest, with a small island in the middle. It is ringed by steep slopes that rise up to six thousand feet. From the air the bay looks something like a fish, with a narrow mouth formed by the spit of land and a T-shaped tail at the opposite end, where the slopes create a nearly vertical wall.

  Ulrich anchored just inside the entrance, along the south shore in thirty feet of water. There were two other fishing boats in the bay, the Badger and the Sunmore, both with two-person crews, and a team of Canadian mountaineers camped on the spit after climbing 15,525-foot Mount Fairweather, the highest peak on the coast, about ten miles to the north. As Ulrich trailed off to sleep at about 9 p.m., he heard the sound of an aircraft, a Canadian Coast Guard floatplane that landed, picked the climbers up and departed. Other than that, the night was breezy but quiet.

  An hour later, he was awakened by a violent rocking. Ulrich knew instantly that it was an earthquake, and a strong one at that. But he wasn’t prepared for what happened about two minutes later.

  From down the bay, he heard a deafening crash. The quake had shaken loose an enormous amount of rock and snow from a mountain at the back of the bay. In seconds, by later estimates, fifty million cubic yards of material fell into the water. It created the kind of splash that happens when a rock is dropped into a pond—only in this case the rock weighed some seventy-five million tons and was dropped from a height of three thousand feet.

  Ulrich saw the splash as he gazed down the bay. It was enormous, he thought—so far beyond anything he’d seen before that he couldn’t begin to gauge its size. But then he saw a wall of water emerging from the lower part of the splash. What had started as an explosion of water was now a mammoth wave. Ulrich guessed it was five hundred feet high. To his horror, it was coming his way.

  He woke Sonny, started the engine and tried to pull up the anchor, to reach deeper water and avoid being pounded into the shore. The wave seemed to be losing height as the bay widened, but it still overtopped the island, which rose to 150 feet at its highest point. Ulrich couldn’t get the anchor completely up, but he managed to turn the boat around so that it was facing the oncoming water, which would give him a better chance to ride it out.

  When it did reach him—perhaps three minutes after the initial splash, Ulrich thought—the wave was about seventy-five feet high. He gunned the engine and headed into it. His anchor chain snapped as the boat rose up. At one point he looked down on the shore and thought that if the wave broke he’d end up in the treetops. But it didn’t break, and instead he rode up and over the crest and down the backside, into the middle of the bay. The wave kept going, across the sand spit that the mountain climbers had vacated about an hour before.

  The two other boats in the bay were not so lucky. The wave swamped them both. The crew of the Badger were able to get into their skiff and were picked up later; the crew of the Sunmore were lost. Ulrich’s boat was tossed about for twenty minutes as the water rebounded from shore to shore, but ultimately the bay calmed down.

  The next day, Don Miller—the geologist who taught George Plafker so much about working in backcountry Alaska—flew over the bay. He’d studied wave-related damage there some years before, occasionally with Plafker, so when he heard about the earthquake he arranged a quick overflight. Intrigued by what he saw, he visited on the ground a month later, climbing up the hillside opposite the rockfall. The splash had acted like a giant scrub brush, scouring the vegetation off the hillside. This was not unusual; Miller and others had seen this phenomenon before, here in Lituya Bay. There was a term for the highest extent of the scouring: the trimline.

  What was astonishing this time was the trimline’s height. Miller had lugged an altimeter with him, and when he reached the highest point of the trimline, the instrument read 1,720 feet above sea level. The splash that occurred that night in July was, and still is, the highest wave ever documented anywhere on earth.

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  Of the thousands upon thousands of earthquakes that happen around the world every year—from imperceptible tremors to powerful shakers like the one that hit Lituya Bay—roughly one in sixteen occurs in Alaska. That makes the state one of the most quake-intensive places on the planet. For a long time, however, no one knew that. In part that’s because for most of history, Alaska was nearly devoid of people. But it’s also because for a long time no one knew much about earthquakes.

  In ancient times, the shaking of the earth was often attributed to the movements of a giant mythical beast. In Japan (another earthquake-intensive part of the planet) that beast was a catfish, thrashing about. In some Native American storytelling, it was a tortoise that carried the world; when it took a step, the earth shook. Once societies moved beyond myths, there were attempts at more-scientific explanations. Earthquakes often accompanied volcanic eruptions, and eruptions usually involved the release of large amounts of gas. So there was some logic to the idea, put forth by Aristotle in the fourth century BC, among others, that earthquakes were somehow related to the movement of gas underground. The concept took many forms over many centuries. Some thinkers believed that earthquakes were caused, not by gases, but by winds in caverns deep within the earth. Others thought they might be related to the collapse of caverns after volcanic gases within them had escaped. In the seventeenth century, the French philosopher-scientist René Descartes wrote that rather than simply moving, perhaps gases actually exploded underground to cause earthquakes. Even a century later, winds or steam or other gases were still the favorite earthquake-causing mechanism of many scientists.

  The idea began to fade in the nineteenth century, for a couple of reasons. Largely as a result of several major earthquakes—one that devastated th
e Portuguese capital of Lisbon in 1755 and a series of five that struck the region of Calabria in southern Italy in 1783—scientists had begun to study seismicity more closely. As they learned more about where quakes occurred, they realized that some happened in places where there was no volcanic activity. And with many quakes they began to notice evidence that the earth had broken—that one piece of the ground had moved in relation to another. The place where this movement occurred was called a fault. Sometimes the movement was horizontal, creating what appeared to be a line in the earth as one block of earth slipped past an adjoining one, and sometimes it was vertical, creating a scarp, or cliff, as one block of earth rose above the other.

  In places where faulting was visible, the question then became a chicken-and-egg one: was the fault simply the result of the shaking that happens during an earthquake, or was it the source of the shaking, the origin of the earthquake itself?

  For a long time in the nineteenth century the answer was that an earthquake occurred somewhere else and that the movement of the earth on the fault was only a consequence of the quake. Contraction theory—the idea that the earth was cooling, and shrinking as it did—proved useful here, as it did in rebutting continental drift. Earthquakes could occur when parts of the crust sank during contraction, the thinking went, leaving breaks in the surface as an indication of the movement.

  As the century progressed, though, scientists began to see the earthquake–fault connection in the opposite way. Of nineteenth-century geologists who came to this conclusion, no one stated it more clearly, and perhaps with more authority, than Grove K. Gilbert.

  Gilbert was born in upstate New York in 1843 and homeschooled until he went off to college at the University of Rochester. After graduating he got work with a company that supplied specimens to museums. It was while excavating a mastodon at a waterfall outside of Albany that Gilbert became interested in landforms and how they changed over time. It was an interest that directed and informed his entire career.

  Itching to do geological fieldwork, he soon landed a job with the Ohio Geological Survey, and two years’ work there eventually got him a recommendation to join one of the great western surveys, being led by an army lieutenant, George Wheeler. As Wheeler’s geologist in the early 1870s, Gilbert explored New Mexico, Arizona and Utah, then joined another of the great survey leaders, Major John Wesley Powell—who had led the first expedition down the Colorado River—for several more years. He later followed Powell to the fledgling US Geological Survey as its first chief geologist.

  On the basis of his explorations with Powell in the Rockies, Gilbert wrote a report on the Henry Mountains in southeastern Utah, considered a masterpiece of thinking and writing about geology, especially the role that water plays in altering the landscape. It was in a lesser-known report, however, that Gilbert set forth his ideas about faults and earthquakes. In his explorations in the West and his thinking about how mountains came to be, he had come across clear signs of faulting in the form of scarps in the Wasatch Mountains of Utah. These spectacular sheer cliffs were created during the process of mountain building, when blocks of crust moved upward. In 1884, in a short report that warned Salt Lake City of the danger of potential earthquakes, Gilbert wrote that “upthrust,” as he called it, distorted and compressed the crust, building up stresses until the force was enough to overcome the friction that keeps one block fixed to another. Then one of the blocks shot upward. “Suddenly, and almost instantaneously, there is an amount of motion sufficient to relieve the strain,” he wrote. “This is followed by a long period of quiet, during which the strain is gradually reimposed.”

  Gilbert had succinctly stated the basic mechanism of earthquakes. It took another major quake, and the investigative work that followed it, for the mechanism to be described in detail.

  That quake was the great San Francisco earthquake of 1906, which occurred along the San Andreas Fault. Unlike the vertical scarps that result from mountain building, the San Andreas moves horizontally. But the same rule applies—stresses act on the fault until they become so strong that it breaks and one side suddenly slips past the other. The fault eventually quiets down and the stresses start to build up again.

  The San Andreas Fault had been recognized for a long time—it is visible on the surface along much of its 810-mile run from Cape Mendocino in Northern California to the Salton Sea in the south. And for four decades beginning in the 1850s, measurements had been made on either side of it, showing that it was gradually deforming—the western side of it was slowly moving north relative to the eastern side. After the 1906 quake, which was centered just off the coast south of San Francisco, new measurements showed that part of the fault had suddenly moved a great distance—in some places twenty feet or more.

  Harry F. Reid, a geophysicist at Johns Hopkins University and a member of the scientific commission that investigated the earthquake, formulated a theory to connect the ground movement to earthquakes. Called the elastic rebound theory, it proposed that forces in the earth caused the rocks on either side of a fault to absorb energy and deform—just as the two sides of the San Andreas Fault had slowly deformed over the years. Once the stresses exceeded the rocks’ internal strength, the fault broke suddenly, releasing much of the stored energy. It was this release of energy that caused the ground shaking and destruction.

  Reid’s theory was gradually accepted over the next several decades, as it helped scientists answer a lot of basic questions about earthquakes. For one thing, it accounted for the varying strength of different quakes: the longer the fault that broke, the stronger the quake, because more energy had been stored and released.

  But the theory did little to answer perhaps the most fundamental question about earthquakes. What was the source of the forces that were acting on the faults, deforming them until they broke? Where was all that energy coming from? The answer to that question would come later.

  Along with a greater understanding of the mechanism of earthquakes, by the late nineteenth century scientists were gaining more knowledge of how often and where they occurred, using increasingly sophisticated seismometers, instruments that could detect the shaking of the earth, often from far away.

  By then, seismometers had been around in one form or another for more than 1,700 years. The earliest-known one was a Chinese invention from the second century. It consisted of a large bronze jar with dragon heads arrayed around it like the points of a compass, a bronze toad beneath each dragon and most likely some kind of pendulum inside. Each dragon held a ball in its mouth. Shaking from a certain direction would cause the ball from one dragon to drop into the mouth of the accompanying toad.

  In Europe, seismometers were first developed in the eighteenth century, with great improvements coming after the Calabrian earthquakes of 1783. In addition to direction, these instruments could give some idea of the power of a quake. But it wasn’t until near the end of the nineteenth century that scientists developed reliable instruments that could measure ground motion over time—what are now called seismographs. The pioneering work on these instruments was done by British scientists working and teaching in Japan.

  With a seismograph providing a time frame, it was now possible to determine, more or less accurately, the point of origin of an earthquake—its epicenter—by comparing the arrival times and directions of seismic waves. Scientists now located earthquakes in all sorts of places—in isolated mountain ranges, or deep under the sea. Throughout the first half of the twentieth century, as instruments became even more sensitive and more broadly distributed around the world, and as communications and data processing improved, seismologists were able to compile lists of thousands upon thousands of earthquakes, including data about their strengths and locations.

  By the 1940s, several things became apparent. First, scientists noticed that the frequency of earthquakes is related to their size—that is, powerful earthquakes are rare, and weak earthquakes happen all the time. We now know that on average there is about one “mega” quake per year, w
hile there are perhaps one hundred thousand quakes that are just strong enough to be felt by someone not too far away, and more than a million that are below the limits of perception of most people.

  But of more immediate interest to the scientists who were becoming convinced that the continents moved—that Alfred Wegener was right, though he may have had the details wrong—was what seismologists learned about the geographic distribution of earthquakes. When quake epicenters were plotted on a map of the earth, several earthquake belts became apparent. Some of them were in the middle of the oceans—one ran north to south in the middle of the Atlantic, and another through the eastern Pacific. This correlated perfectly with the midocean ridges that scientists at Lamont Geological Laboratory had mapped using depth-finder data, beginning in the late 1940s.

  But the largest number of earthquakes ran around the rim of the Pacific Ocean, from Alaska southward along the western coasts of North, Central and South America and then northward through Oceania, Asia and Siberia. This was the same belt that was teeming with mountains and volcanoes. It was now clear that whatever was making those geographic features was also responsible for the earthquakes. Scientists still hadn’t yet figured out what “whatever” was, but by the 1950s they were getting tantalizingly close.