Within minutes Kerry Sieh realized that what he had was far from a disappointment—it was a triumph. If the layers he had sampled ran thirty feet vertically through two thousand years of geologic history clearly interbedded with enough peat to carbon-date the entire array, it would be infinitely more valuable than just a place to measure the offset and get a slip rate.
As he stood there and looked at the lab report on the carbon dates, he began to understand what he had found. Pallett Creek was the very place he had searched so hard to find—the key to the third and most difficult phase of his thesis project—the key to dating historic earthquakes along the San Andreas.
“Kerry, I want you to know something.” Dr. Richard Jahns was looking at the final copy of the finished doctoral thesis that Kerry Sieh had placed in front of him. Jahns knew what it contained, of course, having served as Kerry’s adviser throughout, but as with any ceremonious milestone, the quiet impact of those several hundred pages on the desktop was in stark contrast with the weight of the effort, research, and determination behind it—and a mere whisper of the immense impact that the research contained in those pages would have on the seismological community.
“When you first walked in here with this idea, Kerry, I thought you were crazy. I didn’t think there was any way you could work this out. All of us thought you’d hang yourself.”
Kerry Sieh—soon to be Dr. Kerry Sieh—was surprised. He knew the other professors had had no faith in his idea, but Dr. Jahns had always been supportive.
Jahns patted the thesis, obviously proud of the fact that despite his misgivings, he had seen something in Kerry Sieh that he thought deserved a chance. The idea that one motivated, bright student who believed fervently in his project could overcome the odds with hard work and ingenuity had proved right.
It was July 1977, the month Kerry was to begin as a new geology instructor at Caltech in Pasadena, some four hundred miles down the San Andreas Fault to the south. Most of the previous eight months had been spent refining data, finalizing conclusions, and drawing the last sketches of the strata which had yielded so much (not to mention the late hours typing and revising the manuscript). While the thesis marked the end of the project, it really marked the beginning. Kerry knew he would have to continue digging at Pallett Creek. There were many more secrets to be found—not that he hadn’t unearthed a staggering number already.
There had been a cornucopia of datable material and clearly visible breaks in the various layers representing specific earthquakes, interlaced with sandblows and gopher holes and complex “horizons” of peat and sand and sediment. Kerry had mapped with meticulous precision more than eleven different views of the strata across the fault (which he had exposed through digging long trenches), and had documented Fort Tejon magnitude quakes (within plus or minus forty years) in 1745 (during the American colonial period), 1470 (before Christopher Columbus’s voyage), 1245 (when only Indians occupied North America), 1190 (a century after the Battle of Hastings), and the years 965, 860, 665, and 545. Through his work at Wallace Creek, he had postulated an annual slip rate of 3.4 centimeters along the length of the fault and had constructed a profile of the average offsets—sudden slippage—of the fault from Parkfield to San Bernardino during the 1857 quake. In short, he had asked and answered all three of the major questions.
The significance of what he had found, and what he had validated with such careful precision, was profound. The list of prehistoric earthquakes alone meant that no longer could residents or government officials of Southern California treat the prospect of great earthquakes on the southern San Andreas as the mere armchair postulations of theorizing scientists. This was hard-and-fast proof. Great quakes hit the Fort Tejon area of the fault on the average every century and a half, Kerry had discovered, and had done so at least nine times in the prior fifteen hundred years.
But the fault had not stopped slipping, and therefore, the research meant that with virtual certainty, the fault would break again at some point in the future.
Many people had accepted that fact before, but seismologists always were in such disagreement about when it would happen that there was no sense of urgency. However, simple math—subtracting 1857 from 1977—yielded the figure 120. It had been 120 years since the last quake, and since the record at Pallett Creek indicated clearly that some quakes had been separated by less time than that, the possibility of a repeat performance of Fort Tejon at any time had to be faced.
Now there would be powerful ammunition for scientists and government leaders who wanted to adopt some of the hazard mitigation proposals that Dr. Steinbrugge’s task force (among others) had recommended in 1970. Suddenly the ethereal nature of the concern was about to evaporate under the hot lights of reality which had been turned on by what one solitary young scientist had believed he could find—and did find—in yesterday’s dirt.
But there was more. From his office at Menlo Park Dr. Robert Wallace had followed Kerry’s progress with great interest and enthusiasm. While he knew that the inevitable flurry of interest in the hard facts and implications of Kerry’s thesis would have quite an impact, the project’s success carried a higher magnitude of benefit for geology, and, in fact, for geophysics and seismology as well. The idea that seismologists and geologists needed each other—the concept that such cooperation across interdisciplinary lines could develop a synergistic momentum—had been validated in an exceptional way. This was another quantum leap in the usefulness of the sort of research that Gilbert had pioneered, Plafker had practiced, and Wallace had advocated for decades. This was a field in search of a new title, and Wallace was prepared to name it. The term “paleoseismology” would be exactly right, though it would take some time to gain acceptance.8
But the greatest benefit of all would be in the jolt of enthusiasm that Kerry Sieh’s triumph would give to a growing hope—a yearning—that had fueled papers and studies and endless discussions of what seismology could do for society in the future: the hope of earthquake prediction. In effect, Kerry Sieh’s thesis was an inherent long-term prediction, thoroughly supported and neatly encapsulated. What happened before on the San Andreas at Pallett Creek would obviously happen again. The challenge would be in determining when, for Pallett Creek, Los Angeles, and for all other areas seismologically in harm’s way.
And while the dirt had been flying at Pallett Creek, on opposite sides of the planet new hope had broken out that perhaps there were ways to do it.
Chapter 16
Beijing (Peking), People’s Republic of China—July 28, 1976
The offices of the State Seismological Bureau were quiet and nearly empty in the predawn darkness of summertime Beijing, where only a few personnel remained on duty to monitor the twenty-four-hour-a-day seismographic network and receive incoming calls and teletypes. With more than ten thousand Chinese citizens engaged in watching for early indications of earthquakes throughout the far-flung nation, messages arrived at all hours.
With the vast majority of the one billion men, women, and children in China still living in mud-brick, tile-roofed, unreinforced masonry houses, the fact that much of the nation was riddled with major faults and tectonically active seismic zones was very well understood. Millions of Chinese had died in previous centuries when large or great earthquakes collapsed their brittle homes, and the building materials had changed little over the years in the confines of the ancient civilization that was China.1
In 1966, for instance, a couple of massive shocks fragmented houses and buildings in a region two hundred miles south of Beijing, killing thousands. As Mao Zedong and Premier Zhou Enlai were beginning the disastrous (and murderous) Cultural Revolution (which was to rage for ten years and set Chinese modernization back twenty), Zhou also began a “People’s War on Earthquakes.” He had been shocked by the destruction and the suffering in the Hsing’tai region.
Within the framework of massive social upheaval, and despite the rout of the nation’s scientists and intellectuals (sent into the countryside by th
e thousands to be retrained by the Red Book—waving peasants), the Chinese somehow managed significant advances in seismic research and seismic knowledge. By 1974 they had set up a nationwide army of 10,000 full-time seismic observers, thousands of local monitoring stations and seismographs, 250 regional seismic stations, and 17 major observatories. The amazing network of people and instruments set about monitoring tremors, well water levels, animal behavior, radon gas emissions in wells, strain gauges, and numerous other possible precursors (many such monitoring efforts helped quietly by the displaced expertise of banished scientific minds).2
And by 1975 it had paid off.
Nearly 300 miles to the northeast of Beijing in southern Liaoning Province, Manchuria (about 320 miles north-northwest of Seoul, South Korea), something was happening. The seismologists and the observers alike knew that the continuous reports of everything from weird animal behavior to small swarms of earth tremors marked more than just an active seismic zone; they were the chatterings of a tectonic warning. Since the Hsing’tai disaster, the epicenters of a number of intermediate-magnitude quakes seemed to be “walking” toward the southern Manchurian region, and Liaoning Province in particular. The port of Luda (Dairen) had been rocked by a massive quake in 1856 (a year before the Fort Tejon quake in California), but there had been little industrialization and fewer people at the time. Now, as the menacing northwest march of epicenters continued, the fact that no quakes had occurred in the province for fully 119 years was worrisome in itself. In addition, after much surveying and monitoring, the seismologists had discovered that something was lifting the area around Haicheng and Yingkou, and tilting it slightly to the northwest.
From January through May 1974 the nearby tremors increased to a rate fully five times that of normal years, and the Beijing seismologists decided to put their reputations on the line: They issued a tentative forecast for a major quake within two years.
On December 22, 1974, another swarm of quakes began, the largest measuring just under 5.0 (ML Richter magnitude). In response, the Seismological Bureau tightened its forecast: Expect the quake, they said, in the first six months of 1976. By the first of February the Beijing office was knee-deep in reports from the area. Wells were bubbling, animals were doing exceedingly odd things at unpredictable times, and most of the measured and observed parameters were registering in one direction or another.
Then, on the morning of February 4, a swarm of more than five hundred minor tremors shuddered and rattled through the region, reaching a crescendo with an ominous ML 4.8 jolt, followed by abrupt, absolute seismic quiet.
Suddenly it all had stopped. There were no tremors, no microquakes, and no jolts. No seismic waves of any sort wiggled the seismograph needles. The ominous threat contained in those now-straight lines on the seismograph drums was not lost on the scientists in Beijing. The minutes of seismic quiescence built like the image of a swollen reservoir filling to the breaking point behind a temporary dam.
The seismologists of the State Seismological Bureau, being Chinese, were all very well trained both as scientists and as political realists. They were acutely aware that most difficulties in Chinese life must be considered a political problem, and by that measure, this one was a granddaddy.
They knew they had the power to order the population of several million people out of their homes, and that in their society the people (for the most part) would obey. They also knew that the temperatures in Haicheng and Ying kou were below freezing. And, they remembered only too well how embarrassed they had been over the issuance of a false alarm a few months before—a well-meaning evacuation order that had sent thousands of people fleeing their homes into the Manchurian winter at Panshan (several hundred miles to the northeast), only to be followed by continuous seismic calm.
But the sudden quiet in this case—and after years of activity—was unnerving. While the remaining minutes of the morning of February 4 ticked by with flat seismogram tracings, a worried consensus began to develop as the seismologists slowly resolved their political and sociological worries. Obviously, the consequences if they were right and did nothing would be far worse than the consequences of issuing another false alarm. The total absence of seismic waves could mean only one thing: A great quake was imminent. By 2:00 P.M. they could stand it no longer, and the order went out to evacuate.
Tens of thousand of Chinese began extinguishing cooking fires, shutting down machinery in scores of factories throughout the heavily industrialized area, collecting food and blankets, and setting up camp on lawns and in parks. Three million people were affected, all of them told to expect a cataclysmic earthquake sometime in the next few hours. As the seismologists knew only too well, the audacity of their prediction in naming place, time, and magnitude was unprecedented.
It was also dead right.
At 7:36 P.M. the last snag holding back the dam of seismic strain below the region fragmented, and the rock faces below jerked past each other along one of the major fault planes, pulsing a torrent of P and S waves from the focus of the break. First the compression or primary waves (push-pull waves; P waves), roared beneath them, followed within seconds by the side-to-side ruinous undulations of the secondary waves (S waves). The monstrous waves of pulsed S wave energy had roared a short distance to the surface of the Chinese mainland, and were now yanking the foundations of the cities to one side while throwing them upward in violent and sickening waves of movement, and doing what all great Chinese earthquakes traditionally have done in a nation that has limited lumber resources and great need of masonry for building their homes: destroying 90 percent of the structures within seconds.
As the roofs fell and the walls crumbled, great sheets of strange lights flashed across the sky in all directions, clearly witnessed by millions of frightened people.3 Rail lines twisted like spaghetti, bridges and highways collapsed, sandblows spouted all throughout the area, sending jets of sandy water fifteen feet in the air, and factories fragmented as if hit by a nuclear burst. In 120 seconds southern Liaoning Province lay mortally wounded, and the towns of Haicheng and Yingkou lay utterly destroyed.
However, of the three million Chinese citizens who had fled their deathtrap homes and businesses, only three hundred had died.
As the shell-shocked but living residents began to pick up the pieces, and the Seismological Bureau in Beijing realized that it had averted an unspeakable human catastrophe, the word of the Chinese scientific triumph began to spread to the rest of the planet almost as rapidly as the powerful P and S waves that announced the great quake to a thousand seismographs worldwide.
The successful prediction was a stunning orchestration of manpower, scientific prowess, insight, information, government support, popular cooperation, and bureaucratic intestinal fortitude in the face of dangerous odds. Few outside the People’s Republic of China really appreciated how dangerous (politically, professionally, and personally) had been the actions of the seismologists in Beijing. The fact that mattered to the world—especially the world of seismology—was the profound and undeniable realization that the growing expertise of the science of seismology had directly contributed to the saving of perhaps millions of fellow human beings.
It did not mean that suddenly all earthquakes, there or elsewhere, had become predictable as to place, time, and magnitude, but, to any rational scientist who had ever considered the question—to every governmental official or municipal leader who had ever faced the dilemma of what to do—the Haicheng forecast meant that the possibility of successful earthquake prediction as a tool of the overall process of earthquake hazard mitigation held greater credibility than the day before.
That realization alone would be of great force and influence in the following seventeen months, especially in the United States.
Even within the quiet halls of the crowded Seismological Bureau offices, the relative quiet of the early-morning hours of July 28, 1976, was in marked contrast with the din of daytime Beijing. The sound of passing vehicles could be heard periodically outside t
he windows—the muffled sounds of engine and tires rising above the chatter and buzz of nighttime insects, then diminishing again, as the capital slept. In a few hours the cadre of scientists and assistants would arrive once more in a wave of bicycle-borne humanity as the constant roar of the great city rose to full cry in the background.
And today, one of the areas waiting for more study would be the intensely conflicting data coming from an area just a hundred miles east of Beijing, a city of one million known as Tangshan.
There had been a number of medium-size tremors in the area of the industrial city the year before (just after the successfully predicted Yingkou-Haicheng quake), but there was a growing concern that perhaps those tremors were something other than aftershocks of the Haicheng quake. Maybe, in fact, they were precursors of a larger quake coming in the Tangshan area. The scientists knew that a major fault ran exactly beneath Tangshan; but there was no record of its having caused an earthquake in recorded history, and in China recorded history encompasses several thousand years.
Nevertheless, the bureau had decided to lace the area with a web of sensors and surveillance, which documented a few puzzling magnetic changes and gravitational anomalies, but which in the end justified no more than a carefully vague forecast that there might be a large earthquake in the area sometime in the future.
By late July there were scattered reports of strange animal behavior and fluctuating well water levels, but no clear pattern had emerged. During the dog days of July in the mainland heat of Beijing, the seismologists had pored over the conflicting reports and agreed merely to keep watching. The Haicheng prediction had been a resounding success, but in that case the indications that something was going to happen had become overwhelming to the practiced scientific mind. The situation in Tangshan, on the other hand, was indeterminate.
On Shaky Ground Page 23