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

by Henry Fountain

  It took a long time for science to figure out what that something was. As it turned out, events in Alaska would play a crucial role.

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  In the late 1940s, when he was a distinguished scientist looking back on four decades of accomplishments, the German geologist Hans Cloos would recall the day in 1915 when he first met Alfred Wegener. Cloos, who was twenty-nine at the time, had taken a teaching position at the University of Marburg, in central Germany, after a few years in Asia working for an American oil company. Soon after his arrival, as he later wrote, “A man came to me, whose fine features and penetrating, gray-blue eyes I was unable to forget.”

  Wegener, who was five years older than Cloos, was a lot of things—physicist, astronomer, meteorologist, teacher, explorer—but he was not a geologist. Born in 1880 and raised in Berlin, the son of a theologian, Wegener had studied at universities in Germany and Austria and earned a doctorate in astronomy in 1905. A decade later, Wegener, who by then was concentrating on climatology and meteorology, had already achieved much. He had become an expert on the use of kites and balloons to take atmospheric and celestial readings at high altitudes. He’d taken part in two expeditions to the remote Greenland ice sheet, conducting the first extensive meteorological studies in the Arctic. He had been appointed as a tutor at Marburg and had published a textbook, The Thermodynamics of the Atmosphere, that was already a must-read among meteorology students. But when he came to see Cloos, it was something that he’d started working on several years before—something far afield from any of his formal studies—that he wanted to talk about.

  “He had developed an extraordinary theory in regard to the structure of the earth,” Cloos wrote. “He asked me whether I, as a geologist, was prepared to help him, a physicist, by contributing pertinent geological facts and concepts.”

  The “extraordinary theory” concerned an age-old question: how the mountains and, by extension, the continents had come to be, or, as Wegener looked at it, how the continents had come to be where they are. For he had developed a seemingly wild idea: that the earth’s landmasses were not fixed but instead moved through the oceanic crust. His concept came to be known as the theory of continental drift.

  The first spark of the idea had occurred to Wegener in early 1911, when a colleague at Marburg had shown him a new atlas he had received for Christmas. Looking at a map of the world spread across two facing pages, Wegener noticed something about the continents of Africa and South America: their coastlines, with all their twists and turns, were parallel to each other, although they were separated by thousands of miles of ocean. If one could put the west coast of Africa and the east coast of South America together, they’d fit practically like two pieces of a puzzle.

  This was hardly a unique revelation. Scientists and others had noticed the similarities between the two coastlines since at least the sixteenth century (and it has been apparent to generations of schoolchildren in more recent times). Wegener went a little further. The map he was looking at was a new one, with depth profiles of the ocean floor off both continents, showing the contours of the continental shelf off each coast. These, too, matched quite well. The congruence of the coastlines, then, wasn’t some artifact of erosion or other effect of the oceans.

  To Wegener, what he saw could have only one meaning: the continents were somehow able to move. He could see enough evidence from other parts of the world—the way Europe and North America appeared to fit together, for example, particularly if Greenland was included as a kind of wedge—to think that similar movements had occurred everywhere. He realized, too, that this might explain how mountains arose. Perhaps, as the continents had moved, their leading edges had become distorted and pushed up.

  Wegener had quickly put all these thoughts aside, however, for he had too much else going on, scientifically and otherwise. He had to prepare for one of his Greenland expeditions, which would leave whenever he and his fellow explorers could raise the money for it. And in the middle of 1911 he had to drop everything and spend two months in reserve military training, as the clouds of war were beginning to gather over Europe.

  Wegener was a generalist with a nearly insatiable curiosity, a voracious reader often in fields outside his own. That fall, back from military training, he’d come across an academic paper that had rekindled his interest in his idea. The subject of the paper was geology, and Wegener understood it well enough to immediately draw a connection to his thoughts about continental movement. The paper detailed the strong evidence, from identical limestone formations found in Africa and South America, that the two continents had once been joined.

  With the Greenland trip looming, Wegener put his other work on hold for a few months and furiously plunged into researching his idea. He found other evidence of rock formations that seemed to have formed when the continents were joined: research linking coal deposits in Britain and America, for instance. There were also fossil studies, some of which had been around for decades, which showed that the same species of plants and animals existed on continents that were now thousands of miles apart. One was Glossopteris, actually a group of similar fern species, now extinct. Glossopteris fossils had been found almost everywhere, it seemed, including Africa, Australia, South America and the Indian subcontinent. Other fossil evidence suggested that continents had gone through sharp swings in climate—that what had once been the tropics, for example, was now at a more temperate latitude. This too could be explained if the continents were moving about the planet.

  In just a few months of hectic work, Wegener had written a long treatise, “The Geophysical Basis of the Evolution of the Large-Scale Features of the Earth’s Crust (Continents and Oceans),” outlining his idea. He’d given a lecture at the Geological Association of Frankfurt and another back at Marburg.

  But the reaction had not been particularly enthusiastic (Wegener used the word indignant to describe the reception at Frankfurt). And at any rate, Wegener’s regular academic work had intervened, as had a second expedition to Greenland. He left for Greenland (by way of Iceland) in 1912 and returned the following year. Then, in the summer of 1914, as war was about to be declared, his reserve unit was mobilized. He joined troops that were invading Belgium. The first time he saw action, in late August, he was shot in the arm. After he recovered and was sent to the front in France, he took another bullet, this time in the neck. His career as a soldier over, he was sent home to Marburg.

  In 1915, Wegener took up his theory again, working on a more complete description of it in a book that would end up being titled, more succinctly, On the Origin of Continents and Oceans. Cloos, he figured, could help him get the geology right.

  Over the next two months, the two collaborated. Cloos wrote later that he never fully subscribed to Wegener’s thesis, which “loosened the continents from the terrestrial core, and changed them into icebergs” of rock floating on oceanic crust. But the men became friends, and their constant debate and discussion helped Wegener sharpen his ideas.

  Wegener saw signs of continental drift all over the globe, including the way the Arabian Peninsula appeared to be moving to the northeast. Cloos had traveled through the Red Sea and the Suez Canal on his way to and from Asia, and in one of their discussions Wegener had appealed to his knowledge of the region’s geography. Wegener’s words, as related by Cloos, show how passionate he was about the subject.

  “ ‘Just look at Arabia!’ Wegener cried heatedly, and let his pencil fly over the map. ‘Is that not a clear example? Does the peninsula not turn on Sinai to the northeast like a door on a hinge, pushing the Persian mountain chains in front of it, attaching them on the two hooks of Syria and Oman like drapes!’ ”

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  In the nineteenth century, one of the prevailing ideas of earth science was that the planet was cooling. In this view, the earth had formed as a hot ball and had been losing heat ever since. Like many hot things—a pair of blue jeans just out of the dryer, say—as it cooled, it shrank. Eduard Suess, an Austrian geologist, was among
those who developed this theory of contraction, as it was called, and had come up with an analogy for it that made it easy to understand. The cooling earth, he said, was like a drying apple. As the flesh of the apple shrank, the skin became wrinkled. As the earth’s interior cooled and contracted, its crust folded and wrinkled, forming mountains.

  Suess thought that something else happened as the earth cooled: parts of the crust sank, forming the ocean basins. The parts that didn’t sink were the continents. But he went further, arguing that as cooling and shrinking continued, eventually the landmasses, in turn, would sink below the level of the ocean basins. The continents would become oceans, and the oceans, continents. That would help explain why fossils of marine organisms were often found on what was now dry land, for instance.

  Contraction theory had been widely accepted, but by the turn of the twentieth century there began to be some gaping holes in it. Radioactivity had been discovered in the mid-1890s, and scientists soon realized that the decay of radioactive elements produces heat. Radioactive elements like uranium are abundant in the earth (it was uranium, in fact, that had led Henri Becquerel to discover radioactivity in the first place). So how could the planet be cooling if there was a constant source of new heat deep within it? And if the planet wasn’t cooling, how could it be shrinking?

  There were other problems with contraction, most notably what was being learned about the earth’s crust through gravity measurements like those undertaken in India in the mid-1800s. Crews working for Colonel George Everest, the surveyor general of India (and the man for whom the highest mountain in the world was later named), showed that the continents were less dense, or lighter for a given volume, than the material below them. It’s as if a continent were an ice cube: just as an ice cube floats in a glass of water (because ice is less dense than water) and if pushed to the bottom will pop right back up, it seemed that the continents were “floating” on denser material and that it was impossible for a continent to sink and become an ocean basin.

  The gravity findings supported Wegener’s ideas. He had argued that the continents didn’t move vertically anyway, but rather horizontally. (In his original treatise and book, he referred to “horizontal displacement” rather than drift, though they meant the same thing.) If the continents “floated” on oceanic crust, it was easier to envision them moving around. The movement was no doubt very slow, taking place over millions of years. It was hardly perceptible, yet Wegener was convinced by the evidence that it had happened.

  To have drifted apart, the continents had to at one time have been together. Wegener borrowed a concept that Suess had developed, that the continents at one point formed a giant landmass, a supercontinent of sorts. Suess had called it Gondwanaland. Wegener called it Pangaea.

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  Wegener’s book, a slim ninety-four-page volume, was published in 1915; he revised and expanded it several times into the 1920s.

  The gist of his theory was this: about 225 million years ago, all the land on earth had been part of Pangaea. Then landmasses began to drift apart. As they moved, the leading edges crumpled and formed mountains; that explained why many ranges are found on coasts. Some landmasses would collide and become one, which explained why some mountains were in the interiors of continents. Over time, most of the landmasses had ended up far apart. They were the continents we know of today, and the spaces between them were the oceans.

  Wegener cited the various geological and fossil findings that supported his idea. He also cited the gravitational work that showed that the continents could not sink, and he buttressed this with the fact that the continents were largely made of granite, a less dense, and therefore lighter, rock than the basalts that made up the ocean floors. So it made sense that the lighter continents could move across the heavier ocean basins.

  All of this would occur very slowly, Wegener argued. Continents moved on the order of inches a year. But with enough time, even tortoise-like movements could result in big changes. Wegener theorized that the drifting had occurred over tens of millions of years and was still occurring.

  Like his 1912 treatise, Wegener’s more complete theory of 1915 met with much skepticism. He was widely ridiculed and mocked, in part because he, as a nongeologist, was attempting to tell geologists how the world worked. But it was in 1922, when his book was finally translated into several languages, including English, that the loudest criticisms began.

  Some of the critiques of continental drift stemmed from Wegener’s proposed explanations of how the continents moved. He argued that the forces created by the rotation of the earth could make the continents move slowly across the oceanic crust. Alternatively, the gravitational pull of the sun and moon might provide the motive power. Both of those mechanisms were easily dismissed by scientists with more knowledge of physics than Wegener.

  But much of the rejection of Wegener’s theory focused more on his methods, and on the fact that he was a geological outsider. This sentiment was particularly felt in the United States, where, in 1926, the American Association of Petroleum Geologists organized a symposium in New York City to discuss continental drift. Held at the stately Pennsylvania Hotel, across the street from Pennsylvania Station on Seventh Avenue, the event allowed some of America’s leading earth scientists a chance to sound off about the theory. It was more a kangaroo court than a symposium. Edward Berry, a professor at Johns Hopkins University in Baltimore, attacked the method by which Wegener had arrived at his theory, which, he said, “is not scientific, but takes the familiar course of an initial idea, a selective search through the literature for corroborative evidence, ignoring most of the facts that are opposed to the idea, and ending in a state of auto-intoxication in which the subjective idea comes to be considered as an objective fact.” The paleontologist Charles Schuchert, who had headed Yale’s natural history museum and who knew as much about the distribution of fossils around the world as anyone, accused Wegener of being far out of his depth. “Facts are facts,” Schuchert wrote, “and it is from facts that we make our generalizations, from the little to the great, and it is wrong for a stranger to the facts he handles to generalize from them to other generalizations.”

  The world of geology was being divided into two camps in relation to what had come to be called “tectonics”—the processes that affect the earth’s crust. One, the mobilists, accepted the basic premise of Wegener’s theory, even with its flaws. The other, the stabilists (sometimes also known as fixists), stuck to the older contraction theory or some updated variant of it (Schuchert himself at one point proposed the idea of “land bridges” that connected the continents and came and went). By the mid-1920s, the stabilists were prevailing, and Wegener was suffering for it. He had been hoping for a full professorship at Marburg or another university in Germany but was continually turned down for advancement. It was not until 1924 that he received a faculty appointment—in meteorology, in Austria, at the University of Graz.

  Wegener published a new edition of On the Origin of Continents and Oceans in 1929, and in the next year he left on his third expedition to Greenland. Where the first two expeditions had been organized and led by Danes, this time Wegener was the leader. The main goal was to set up permanent weather stations on the ice sheet. But there were problems with logistics, and after journeying to the middle of the ice in late fall to resupply one of the stations, Wegener and another member of the expedition set out to return to their base camp. They never made it back. Wegener’s body was found the next year; he had apparently died of heart failure along the way. He had just turned fifty years old.

  Wegener died knowing that his theory was largely discounted within the scientific community. In the world of earth science, stabilists were to rule the day for the next three decades. But beginning in the 1940s, new evidence was uncovered from beneath the oceans that supported the idea that the continents moved—though not in the way Wegener had thought.

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  War may be good for very little, but occasionally in the world of science, a
t least, it can be helpful by spurring discoveries. That was the case during World War II, when, as a side benefit to the American military campaign to beat back the Japanese in the Pacific, a scientist named Harry Hess laid the groundwork for a fuller understanding of the subject that Wegener had explored years before.

  At the time, late in the war, Hess was the captain of the USS Cape Johnson, a navy attack transport that delivered troops for landings at Iwo Jima, Leyte and other locales in the Pacific theater. The Cape Johnson was equipped with a powerful fathometer, a sonar device that pings sound waves off the ocean floor, using the reflections to measure depth and create a profile of the bottom. Depth finders like this were useful to the military, especially for making charts of shallow waters that showed reefs or other hazards. Hess dutifully used his fathometer in that way, but he did something else—he left it on all the time, even when he was far from land.

  Hess was no ordinary naval captain. Raised in Asbury Park, New Jersey, and a 1927 graduate of Yale, he’d received a doctorate in geology from Princeton in 1932 and had taught there and at Rutgers before the war. He had also participated in a field study in the Caribbean, making gravity measurements from a navy submarine. For the submarine work he’d had to become a navy reservist, so when the Japanese attacked Pearl Harbor in 1941 Hess reported for active duty the next day. He spent a couple of years analyzing the patterns of German U-boat movements in the Atlantic, helping the Allies to all but eliminate the threat from the submarines, before shifting to the Pacific.

  Leaving the fathometer on day and night as the Cape Johnson steamed along—even diverging slightly from its assigned course at times, in the name of science—Hess obtained contour maps of a sizable portion of the North Pacific. The maps revealed that the seafloor was littered with features, including canyons and trenches and, most strangely, flat-topped mountains that rose from the seafloor yet ended hundreds or thousands of feet below the ocean surface. Hess counted more than 150 of them and named them guyots, after Princeton’s first geology professor. To Hess, these were clearly old volcanoes that had had their tops eroded by the ocean. Together with what he’d learned from the work in the Caribbean, which showed that extremely deep parts of the ocean had lower than normal gravity, the nature of the oceanic crust was beginning to be revealed. Rather than a vast boring expanse of rock, the seafloor, like the continents, showed signs of geological activity. It would take more than a decade, and more detailed mapping and other studies by a number of researchers, for Hess to propose what that activity was.