The Earthquake Observers

Disaster Science from Lisbon to RichterBy DEBORAH R. COEN

The University of Chicago Press

Copyright © 2013 The University of Chicago
All right reserved.
ISBN: 978-0-226-11181-0

Contents

Introduction……………………………………………………………….1ONE / The human Seismograph………………………………………………….15TWO / The Planet in the Village: Comrie, Scotland, 1788-1897…………………….25THREE / news of the apocalypse……………………………………………….45FOUR / The Tongues of Seismology: Switzerland, 1855-1912………………………..69FIVE / Geographies of hazard…………………………………………………103SIX / The Moment of Danger…………………………………………………..125SEVEN / Fault Lines and borderlands: Imperial Austria, 1880-1914…………………141EIGHT / What Is the earth?…………………………………………………..163NINE / The Youngest Land: California, 1853-1906………………………………..187TEN / a True Measure of Violence: California, 1906-1935…………………………215Conclusion…………………………………………………………………267Acknowledgments…………………………………………………………….279Notes……………………………………………………………………..281Bibliography……………………………………………………………….315Index……………………………………………………………………..345

Chapter One

The Human Seismograph

The word “seismology” was coined in the 1850s, not long after the word “scientist”—both harbingers of a new age of technical expertise. Earthquakes, however, did not fit easily into the emerging rubric of professional science, not least because they forced scholars to rely on the testimony of common folk. Already in the sixteenth century, when stories of the new World were first circulating in Europe, Michel de Montaigne remarked that earthquakes compelled Europeans to trust the word of “barbarians.” In a crucial twist, however, Montaigne suggested that the barbarian might prove the more able witness: “a simple, crude fellow—a character fit to bear true witness; for clever people observe more things and more curiously, but they interpret them; and to lend weight and conviction to their interpretation, they cannot help altering history a little.” Echoes of Montaigne’s charitable perspective could be found in subsequent European studies of earthquakes, in the virtues sometimes attributed to untutored observers. Well after Montaigne’s death, earthquakes were still widely discussed across divides of birth and education. Eighteenth-century sermons and news articles engaged the public in scientific and theological debates about earthquakes. Accounts of the new Madrid earthquakes of 1811–12 became “a form of conversation,” in which settlers modeled their descriptions of tremors on narratives of sickness and health. In the early nineteenth century, however, this inclusive conversation was breaking down. Earthquakes figured counterintuitively in new geophysical theories as the effects of elusive electrical forces. Seismology seemed ready to become the esoteric subject of expert knowledge.

The history of seismology since 1755 is traditionally seen as a progressive liberation of natural knowledge from the subjective impressions of earthquake victims. After the Staffordshire quake of 1777, for instance, Samuel Johnson warned that the event would “be much exaggerated in popular talk: for, in the first place, the common people do not accurately adapt their thoughts to the objects; nor, secondly, do they accurately adapt their words to their thoughts: they do not mean to lie; but, taking no pains to be exact, they give you very false accounts. A great part of their language is proverbial. If any thing rocks at all, they say it rocks like a cradle; and in this way they go on.” In this vein, the Calabrian earthquakes of 1783–84 typically figure as the first to have been described scientifically. Their importance—according to the most illustrious of nineteenth-century geologists, Charles Lyell—”arises from the circumstance, that Calabria is the only spot hitherto visited, both during and after the convulsions, by men possessing sufficient leisure, zeal, and scientific information, to enable them to collect and describe with accuracy the physical facts which throw light on geological questions.” Lyell made it seem self-evident that scientific descriptions of earthquakes could come only from men of science.

What Girls Will Tell

Others hoped to dispense with human witnesses entirely. Robert Mallet’s study of the Neapolitan temblor of 1857, subtitled First Principles of Observational Seismology, is often cited as the founding work of empirical macro-seismology. Mallet, a British civil engineer, showed how cracks in masonry and overturned objects could be used to infer the direction from which seismic waves had propagated. He based his research almost exclusively on architectural damage, and found little use for eyewitness testimony. Indeed, Mallet complained to Lyell of the lazy Neapolitan savants; he saw no reason to believe their reports of nightly aftershocks, since he himself had slept just fine. In Mallet’s judgment, lay observers lacked the “observational tact and largeness [sic] of a disciplined imagination and eye that are amongst the accomplishments of the physical field-geologist.” He repeatedly insisted that the untrained eye simply failed to see. In the past, earthquakes had been studied in the absence of “any guiding hypothesis, of any distinct idea of what an earthquake really is, of any notion of what facts might have been of scientific importance to observe, and what were merely highly striking or alarming …—in the want of all these, as well as of any calmness or unexaggerative [sic] observation during such alarming visitations, few facts of the character and precision requisite to render them of value to science can be collected with certainty. The true observation of earthquake phenomena is yet to be commenced…. The staple of earthquake stories, in fact, consists of gossip made up of the most unusual, violent or odd accidents that befell men, animals, or structures, rather than of the phenomenon itself.”

Mallet’s disdain for the “gossip” of human observers was echoed by many British, Italian, and Japanese contributors to seismology in the second half of the nineteenth century. When the Italian Earthquake Commission was established in 1883, it focused on constructing seismographic observatories, not a permanent network of observers. This was in keeping with the move to exclude amateur observers from Italian astronomy in the aftermath of national unification. The private network developed by Count Michele Stefano de Rossi in the 1870s consisted entirely of fellow gentlemen-naturalists, nearly half of whom owned seismoscopes or seismographs. In Japan, where John Milne and Fusakichi Omori pioneered instrumental seismology in the 1880s and 1890s, lay observers played little role in earthquake investigations. Milne seems to have given up on the collection of felt reports after his investigation of the Yokohama earthquake of 1880, for which he sent out five hundred questionnaires and received only twenty-six responses. A leading British seismologist speculated that such outreach efforts failed in Japan in part because Japanese earthquakes were so frequent. “The detailed inquiries which are possible in Great Britain can hardly be made in a country in which the recollection of one shock is soon after dimmed or erased by the occurrence of another or many more in rapid succession.” As Milne put it, the Japanese chatted about earthquakes the way the English chatted about the weather. In any case, he had little patience for the analysis of felt reports: “Attempts to find out what sensations were experienced by the people at the time of the shock are unsatisfactory. People questioned will tell trivial circumstances—how they tumbled from the top to the bottom of the stairs whilst hurrying to get out of doors—girls tell how they began to cry, etc.” Likewise, many of Japan’s historical sources on earthquakes were judged by Westerners to be “of a trivial character”—illustrated, for instance, by a 1707 account of a young man drinking with friends in a teahouse when an earthquake knocked him down a ladder into a barrel of pickled radishes.

It was, therefore, against his better judgment that Mallet began to collect witnesses’ descriptions of the sounds accompanying the Italian tremors. He warned his reader that reports of sounds, unlike the hard evidence of architectural damage, were compromised by numerous distortions: “Echoes, the disturbance of local noises at the moment, the uncertainty with which the ear judges of direction and sound, the evanescence of the phenomenon, and the difficulties inseparable from trusting to merely collected information of often incompetent observers, or unfaithful narrators, who observed under alarm, must ever deprive sound phenomena (except when heard by the physicist himself) of the unerring certainty of deduction, that belongs to the mechanical problems, presented by the phenomena left after the shock.” With his insistence on the “unerring certainty of deduction” and the superior observational skill of “the physicist himself,” Mallet verged on a caricature of the Victorian expert—the Sherlock Holmes of earthquakes.

And yet, to his own surprise, Mallet found that reports of sounds, despite their ambiguities, “are not without their seismic significance.” Suddenly the voices of the earthquake victims themselves intruded into his treatise. On the periphery of the area in which sounds were audible, observers described a “low, grating, heavy, sighing rush,” while those in the center reported a rumbling or (here Mallet felt compelled to quote the original Italian), “rombo, rumore di carozzo … fischio, sospiramente…. These descriptions, aided by the expressive gesticulation and imitative powers of the narrators, conveyed a far more exact notion of the sounds heard, and of the relative times in which they were heard, than I can hope to transmit in writing. … They were collected in my progress … without much idea of their leading to any very distinct or valuable conclusion. The result however now appears to support the conclusions arrived at, from the rigid methods of tracing the origin out from the wave-paths.” These rushes and rumblings, then, only found a place in Mallet’s treatise because they corroborated his theory. Despite his “physicist’s” instincts, Mallet reluctantly acknowledged the force of the testimony of earthquake witnesses, full of meanings that escaped translation.

A “Damned” Science

Despite the confidence of these new experts, the barriers to establishing seismology as a professional science remained steep throughout the nineteenth century. One problem was that there were no limits to the kinds of observations that might be relevant to earthquake research. According to theories widely accepted in the nineteenth century, earthquakes might be triggered by volcanoes, barometric fluctuations, atmospheric electricity, geomagnetism, humidity, or the positions of celestial bodies. Analysis of the course and impact of earthquakes required an even wider variety of data, from the geological to the zoological and psychological. Geographically as well, earthquakes presented no clear limits. Speculation was rife over the apparent coincidence of earthquakes across vast distances, and the subterranean channels that might account for such teleconnections. This uncertainty about what constituted seismology’s evidence brought the field into precarious contact with such “pseudosciences” as astrology and spiritualism.

Earthquakes figured prominently, for example, in the manifestos of Charles Fort, one of the most celebrated skeptics of twentieth-century science. His followers in the International Fortean organization continue to this day to hold annual conferences devoted to “anomalous phenomena.” Fort’s first major publication, The Book of the Damned (1919), was “a procession of data that Science has excluded.” “Damned,” in Fort’s vocabulary, meant rejected by “Dogmatic Science.” Fort wrote in an absurdist style that lurched between bombastic pronouncements and nuggets of humble common sense. Among the “damned” were correlations he uncovered between earthquakes and astronomical phenomena. To collect these “lost souls,” he mined the reams of earthquake catalogs and observational reports published in scientific journals since the late eighteenth century. He was also a zealous collector of newspaper clippings—but then, so was any self-respecting seismologist circa 1900. The research process he described would have been familiar to any of them: “I have gone into the outer darkness of scientific transactions and proceedings, ultra-respectable, but covered with the dust of disregard. I have descended into journalism. I have come back with the quasi-souls of lost data.” earthquakes suited Fort’s hunt for “the damned” precisely because of the minor explosion of seismological observations in the nineteenth century.

The First Seismographs

Seismology’s credibility hinged on the design of instruments to measure physical phenomena independently of their human impacts—to complement, not replace, the observations of human witnesses. While seismoscopes had been used since ancient times in China, modern European efforts to build them began in earnest in Italy in the late eighteenth century. An eighteenth-century seismoscope consisted of a hanging pendulum attached to a stylus that made a mark when set in oscillation. Not until the 1840s were seismoscopes capable, in principle, of measuring the displacement of the ground during a tremor. In practice, they often did not work. The inverted-pendulum seismoscopes installed during an earthquake swarm in Comrie, Scotland, in the 1840s were state of the art. Yet residents of Comrie counted sixty shocks in one year, while the seismoscopes only recorded three. More useful instruments were developed by British engineers in Japan in the 1880s. These “seismographs” were able to trace the development of earthquake waves over time. They recorded pendulum movements on a revolving drum attached to a clockwork mechanism, producing a curve from which the waves’ period and amplitude could be measured. Such traces became all the more interesting in 1889, when a German astronomer discovered by accident that his instruments in Potsdam had inadvertently recorded a strong earthquake near Tokyo: they had detected waves from a spot 5,500 miles away on the earth’s surface. The realization that earthquakes could be mechanically recorded at such a distance inspired many new seismographic inventions at the end of the nineteenth century.

But were these ingenious mechanisms any more reliable than human witnesses? The first generation of seismographs was subject to small “self-oscillations” due to lack of damping, making it hard to record long-period motions. Few were able to record vertical motion. With further improvements, seismographs became more trustworthy; but humans did not necessarily become less so. At the turn of the twentieth century, scientists studying seismographic curves discovered two kinds of seismic wave traveling through the earth’s core: a shorter period “primary” (compression) wave and a longer period “secondary” (transverse) wave. Later research also found several varieties of surface wave, which pass only through the crust. It soon became clear that many apparent contradictions in the felt reports of years past—conflicting accounts of jolts and rolling motion, “horizontal” and “vertical” shocks—were resolved if one admitted that people, too, could feel the differences between these types of wave. Moreover, recent evidence has suggested that humans may be more acute observers than even the latest computerized seismographs. A 2008 study concludes that “events with a magnitude smaller than 1, and even negative magnitudes [meaning, on the logarithmic scale, fractions of a unit shock], can be felt, thus making the human being an instrument eventually much more sensitive than monitoring networks.”

Nonetheless, by the early twentieth century, the availability of seismographs allowed many earth scientists to dream of turning their discipline into a quantitative, objective science, modeled on physics. They transformed what counted as evidence of the earth’s history. Out went data filtered by human bodies; in came the “hard” evidence of seismographs and accelerometers. This was the moment when scientists began to distinguish the “new seismology” from the “old.” Among the achievements of the new seismology was the ability to use instrumental traces of the passage of seismic waves as clues to the internal structure of the earth. The seismograph became a telescope trained on the earth’s hidden depths, where it revealed a core of iron buried under a mantle of rock. The next “revolution” came with the acceptance of plate tectonic theory, the “new geology,” in the 1960s. Plate tectonics overthrew the belief that the positions of the continents and oceans were permanently fixed. Earthquakes took on new significance as evidence that the movement of the continental plates was still in progress. In principle, macroseismic observations should also have acquired new value as clues to the detailed distribution of faults and thus the contours of the plates. On the global scale of the new plate tectonics, however, details of local seismicity tended to fade from scientists’ attention. They took little interest in intraplate earthquakes, which remain poorly understood—though potentially destructive. At the same time, the globalization of news in the early twentieth century made reports of local tremors ever less likely to find their way into print. Working knowledge of the geography of seismic hazard was fast disappearing.

(Continues…)

Excerpted from The Earthquake Observersby DEBORAH R. COEN Copyright © 2013 by The University of Chicago. Excerpted by permission of The University of Chicago Press. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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