Earthquake Storms

by John Dvorak

  But for now, as the geologic work was ready to commence, California politicians and businessmen and other prominent citizens came around often to the Montgomery office to become acquainted with Whitney and his assistants and to find out what they were doing—and to learn what they were discovering. Newspaper editors became especially fond of “the scientific men from Massachusetts,” quoting them at every opportunity. By the end of their first month in California, the five men were already well known, though not one of them had yet sampled or studied a single rock.

  By January 1861, Whitney and his assistants had assembled enough equipment to begin serious fieldwork. They had land-surveying instruments they’d brought from the East Coast that would be used to make topographic maps, a key element to conducting a geologic survey. In California, they purchased a medium-sized wagon with heavy braces, because few roads yet existed in the state. They also purchased a team of four strong mules to pull the wagon and an additional six mules for the men to ride and to carry extra equipment. Each man was issued a revolver and a large knife. Two carbines and two double-barreled rifles were included, considered essential parts of the camp gear. And each man was instructed that, whenever he left camp or went into a town, he was to carry a gun, knowing that if unscrupulous men saw that he was well armed, they would leave him alone.

  Once they got under way, the five men soon discarded their East Coast attire, which had devolved into rags, torn apart by chaparral and jagged rocks, and adopted the rugged denim pants and rough flannel shirts of the gold miners. They also acquired cowhide boots and broad-brimmed hats. And though when he was at home Whitney insisted that clean sheets be placed on his bed every day and refused to wipe his hands twice on the same towel, when in the field he, as well as the others, learned to sleep in the open on oilcloth and to cover himself with a single blanket.

  They cooked for themselves and ate whatever was at hand. They became skilled at washing clothes in muddy creeks and in carrying delicate mapping instruments up steep slopes in all weather conditions. In reading through their journals, one learns that they also came to handle, even to admire, the cantankerous California mule.

  For four years, Whitney and his team of assistants crossed the state, descending into every major river valley and climbing to the crest of every major mountain range. Their travels and accomplishments were glorified in local newspapers. Whenever they passed close to a sizable town, community leaders sought them out, anxious to associate themselves with Whitney and his team of geologists.

  In 1864, in recognition of his leadership, his men named the highest peak in the Sierra Nevada Mountains—which is also the highest point in the contiguous 48 states—Mount Whitney. The same year, this expert on mineral ores issued his first major report. Its contents shocked the people of California when they read it because, instead of telling where additional mineral deposits might be found, this 236-page tome described something else—paleontology!

  The public’s outcry was immediate: Why had so much public money been used to uncover the bones of long-extinct reptiles, to illustrate the imprinted skeletons of long-dead fish, and to describe the shells of useless clams? In scanning through the hundreds of pages of text based on four years of intense fieldwork, one finds the word “gold” only three times and the words “wealth” and “riches” not at all.

  One outraged citizen carried the tome to the state assembly and antagonized legislators in their offices by reading sections to them. And the legislators reacted. They reduced both Whitney’s annual salary and his budget by half. He responded by leaving the state and returning to Massachusetts, where Harvard College honored him with a professorship. It was there, in the halls of the nation’s oldest and most distinguished academic institution, that Whitney prepared a second report that he entitled simply Geology.

  The people of California read the second tome with great interest. At least this time there were nearly 200 pages—the middle third of the report—that described the gold-bearing regions of the state, focusing, not unexpectedly, on the Mother Lode, the 100-mile-long stretch at the base of the western Sierra Nevada Mountains where the most productive veins of gold had been discovered in January 1848. The report told how Whitney and his men had visited almost every major gold field in the state and how they had entered almost every major mine. The report described the geologic setting of each one, though here Whitney committed an unforgivable offense: Showing either an ignorance of or a total disregard for political realities, he pronounced more than half of the mining claims in the state as either worthless or unproductive. And, more than that, there was an important element missing from the report: There was no indication where additional gold might be found.

  This lack of telling where new gold strikes might be made caused the state legislators to act again. This time, they cut Whitney’s salary and his budget to zero. Now a Harvard professor, Whitney continued to live in Massachusetts, making an occasional trip to California to continue his fieldwork, his efforts now supported by private sponsors in New England and by benefactors of Harvard’s museums.

  In 1874, still without any new prospects as to where additional mineral ores might be found, the California state assembly voted to formally end the job of state geologist.

  Today Whitney’s Geology is regarded as a masterpiece, exquisitely written and describing not only the geology of California but also its fauna and flora, much of it now gone. Whitney recounts a visit to Yosemite when the valley was still pristine. He is the first to use the term “High Sierra.” And he tells of personal adventures in confronting flash floods and assisting local lawmen who were searching for desperadoes. One of the few errors in his Geology is his assessment of the potential for an oil industry in California in which he stated that the oil-rich deposits known along the coast would never be of commercial value.

  Because the survey work was begun during winter months, he and his assistants had started in the southern part of the state, where they took time, as the governor had requested, to investigate rumors of the discovery of a major tin deposit south of the San Bernardino Mountains.

  By the time they arrived, hundreds of claims had already been made, covering all the hills and ridges for miles around. But as far as Whitney could determine, a tin-bearing mineral, cassiterite, could only be found at one spot: at the Cajalco Mine. And that mine, at the time he visited, consisted of a single shaft dug down only 36 feet and was mostly filled with water.

  Nevertheless, Whitney collected rock samples from the Cajalco Mine and sent them to Boston and to New York to be assayed. The results were as he predicted: Though one sample yielded 60% metal, the others showed only small amounts. In all, Whitney thought the discovery was interesting—the Cajalco Mine is the only known occurrence of tin ore along the Pacific coast north of Mexico—but of little commercial value, a judgment borne out by a century of repeated attempts to extract ore from the mine.

  It was fortunate—or perhaps unfortunate—that the first glimpse that Whitney had of California’s geology was in the region around the Cajalco Mine because here the geology is extremely complex. There are no simple horizontal strata, arranged in layer-cake fashion, as visible in places like the Grand Canyon, indicative of what much of the earth looks like beneath our feet, and no simple upturned rocks and a few great folds that are so prevalent in the eastern half of the United States and across Europe, areas that Whitney had already studied. Instead, what he saw south of the San Bernardino Mountains was, in his words, “a Gordian knot,” “a curious snarl.” Today we understand the cause for this geologic maelstrom: It is the San Andreas Fault.

  Whitney crossed the San Andreas Fault many times during his years of exploration, though he never recognized any of the features as indicating a geologic fault—nor would anyone for another 30 years. Today we see the same landscape and the same features with different eyes.

  At San Bernardino, north of the Cajalco Mine, one can see three long mountain ranges.
To the west are the San Gabriel Mountains. Immediately to the north and extending to the east are the San Bernardino Mountains. Separating them is a low area known as Cajon Pass, a corridor where vital lifelines pass—oil and water pipelines, electrical power lines, and the I-15 freeway that links Los Angeles and Las Vegas. Cajon Pass exists because the San Andreas Fault runs through it, forming the boundary between the San Gabriel and San Bernardino Mountains.

  South of the city of San Bernardino are the San Jacinto Mountains, and they are separated from the San Bernardino Mountains by another low area, San Gregorio Pass, also a corridor used by pipelines and power lines and a freeway—the I-10 that connects Los Angeles and Palm Springs. Again, the San Andreas Fault is responsible for this pass and for the separation between the two mountain ranges.

  But none of this was obvious to Whitney. As California’s first geologist, he was perceptive enough to realize that there was something unusual here, something interesting. He also realized there were other geologic oddities in the state.

  After completing a reconnaissance of the geology around the Cajalco Mine and San Bernardino, Whitney and his team of assistants moved west, following the southern base of the San Gabriel Mountains. They took time to pass through Los Angeles, then merely a settlement of a few thousand people, and inspect the sedimentary beds exposed by the Los Angeles River. From there, they continued to the Pacific Ocean and to Santa Barbara, where they picked up the old Spanish trail, El Camino Real, the King’s Road, built a century earlier to connect Spanish missions, and headed north.

  At Monterey, Whitney noticed that the old town was nestled against a block of white granite. He followed the granite south as far as the picturesque bay at Carmel, which he foresaw would “at some future time become a place of resort, if not for the fashionable world, at least for those who would combine, with the enjoyment of the ocean breezes, the pursuit of geological, botanical, or zoological studies.”*

  He tried to follow the granite farther south along the coast, but the cliffs were too steep, and he and his four men turned and continued north.

  Again, along the coast just before reaching San Francisco, Whitney found another huge block of granite that, by all appearances, was identical to what he had seen at Monterey and Carmel. Later, working north of the Golden Gate, he found yet again huge blocks of the same granite, this time forming the peninsula of Point Reyes and the sea head at Bodega Bay and, 30 miles from the coast, comprising the Farallon Islands. Such blocks seemed to be scattered for hundreds of miles along the California coast.

  Two summers later in 1862, he uncovered an even greater surprise. Whitney made his first trip to the gold mines of the Mother Lode. After that, he swung around the southern end of the Sierra Mountains and there, exposed in the core of California’s highest mountain range, was the same white granite—identical in mineral content with what he had seen hundreds of miles away along the coast.

  He took samples and sent them to Yale College for analysis, as he had done with samples of granite collected along the coast. The results were remarkable: By every measure the granite in the core of the Sierra Nevada Mountains is identical to that found along the California coast.

  How was this possible? He had no explanation.

  Today, after a century and a half of additional work, which includes more refined chemical and mineralogical analyses of thousands of rock samples, extensive radiometric age dating of many of the same samples, and detailed geologic mapping that, in part, reveals a host of geologic structures, we know why: The blocks of granite that lie along the coast, which are part of a large feature known as the Salinian Block (named after the Salinas Valley north of Monterey), have actually slid hundreds of miles from where they formed at the southern end of the Sierra Nevada Mountains. Moreover, the sliding took place by a seemingly countless number of earthquakes that have occurred over eons along the San Andreas and nearby faults.

  In all, this movement is a remarkable testament to the power and persistence of Earth’s internal forces. A mountain range may get pushed up a few miles, but in California, whether one stands on a rocky outcrop of white granite at the edge of Monterey Bay or midway up the steep cliffs at Point Reyes, beneath one’s feet is evidence for hundreds of miles of horizontal displacement. It is equivalent to a piece of real estate the size of Manhattan Island sliding from Pittsburgh to New York City.

  But nearly a century would pass after Whitney’s original work before this was clearly realized. During his era, what earthquakes were and what their accumulative effects could be was not understood. In fact, he and his contemporaries downplayed the role of earthquakes in geologic history. He himself did not even consider California to be especially prone to such events. In one of his annual addresses to the state assembly, he told legislators: “Luckily for us, California does not seem to be in the region of heavy shocks, so that whatever feeling of insecurity may have once existed on this account seems to have nearly died out.”

  Though he did concede, in his book Geology, that earthquakes, acting locally and in the distant past, were responsible for some of California’s spectacular features such as Yosemite Valley, where strong seismic shaking had caused the valley floor to collapse. By and large, those in academic circles agreed with him.

  But such ideas were woefully inadequate. And the fact that they were inadequate was pointed out by an unlikely source: a man of limited education who came to Yosemite Valley a few years after Geology was published. He had read the book thoroughly and proclaimed that Whitney’s ideas about earthquakes and their consequences were wrong.

  Born in Scotland in 1838, John Muir immigrated to the United States with his family at the age of ten. They settled on a small farm in Wisconsin where life was harsh, made all the more difficult for the boy due to the fact that his stern father punished him whenever he committed any perceived sin—and even when he had not.

  In the 1860s, Muir attended classes for two years at the University of Wisconsin in Madison, receiving his only formal instruction in science. Here the professor of natural history was Ezra Slocum Carr, who often led his students on hikes through nearby fields and woods, investigating, as he put it, “Nature’s basement rooms.”

  Of particular interest to Carr—and catching the attention of young Muir—was the abundance of geologic evidence for glaciers. There were rocky moraines that marked the terminal points of glacial lobes, deep grooves that recorded the scraping of rocks that had been pulled by slow-moving glaciers over a hard ground surface. There were also plenty of boulders—known as “erratics”—that had been transported great distances by flowing glaciers, then dropped as the surrounding ice melted away.

  Muir, too poor to continue a formal education, found work at a factory that made parts for horse carriages. One day, as a result of his own admitted carelessness, he had a terrible accident. He was replacing a machine belt when, while holding a sharp file, the belt slipped, causing his hand to snap back and push the file into his right eye. Months of blindness followed. When his eyesight did recover, he vowed to forgo a life of pursuing comfort and security and instead see the beautiful parts of the world.

  After a year of traveling, first by foot from Wisconsin to Florida then by ship to Panama and California, he found himself in San Francisco waiting for a ship to the Hawaiian Islands, when he decided to postpone that trip and remain in California a little longer. During his convalescence, a friend had brought him a stack of books and papers to read. Among them was a pamphlet complete with photographs that showed a beautiful place called Yosemite Valley. He decided he needed to see it before heading out into the Pacific.

  He crossed San Francisco Bay on the Oakland ferry, then, armed with only a pocket map, he set out on foot for Yosemite, 200 miles away. He arrived at the entrance to the valley on July 11, 1868. He noticed there were boulders in a broad field, not piled up like debris but strewn around as if they had been dropped. Inside the valley, he recognized grooves s
craped across bedrock, as he described them, “striated in a rigidly parallel way.” He also found mounds that could only be glacial moraines. The grooves and the mounds of the boulders—erratics, similar to the ones in Wisconsin—were clear evidence that Yosemite Valley had once been “overswept by a glacier.” Perhaps, Muir speculated, a huge glacier carved its way through during the Ice Age and dug out the valley itself. He decided to consult the only recognized authority: the first guidebook of Yosemite Valley, written by Josiah Whitney and much of it taken from his Geology. Muir was surprised by what Whitney had written.

  Whitney acknowledged that glaciers had once capped the Sierra Nevada Mountains but, he reasoned, they could not have formed Yosemite Valley like Muir had speculated. His main argument against large-scale glacial action was this: Where is the material that glaciers supposedly removed from the valley? The erratics were just one sign of a possible glacier but there were no others, including a lack of huge moraines on the plain near the valley entrance.

  Furthermore, Whitney discounted the idea that Yosemite Valley was a fissure in the Earth’s crust: The valley was much too broad and flat-floored to support such an explanation. And it could not have formed by water erosion because mountain streams, like the Merced River, which flows through Yosemite, form narrow valleys, not broad ones with steep sides and flat floors. And besides, where was the material that river erosion would have removed?

  So Whitney was left with only one geologic agent that could explain the existence of Yosemite Valley—an earthquake.

  In Whitney’s view, a single local and rare cataclysm—a powerful earthquake—had caused the floor of Yosemite Valley to drop suddenly, forming the spectacular vertical walls of Half Dome and El Capitan. It was such a cataclysm that explained why Yosemite Valley was unique in the Sierra Nevada Mountains.