The Big One: the Earthquake that Rocked Early America and Helped Create a Science

Natural History, Sept, 2004 by Laurence A. Marschall

The Big One: The Earthquake that Rocked Early America and Helped Create a Science by Jake Page and Charles Officer Houghton Mifflin, 2004; $24.00

Which of the lower forty-eight states has survived the most powerful earthquake ever recorded in the United States? Strange to relate, the answer is not California, but Missouri. In the middle of the night, on December 16, 1811, the residents of the town of New Madrid awoke to a churning in their stomachs and a rumbling in their ears. Stumbling into the darkness, they saw the ground flapping like a wind tossed sheet, buildings crumbling all around, and, some claimed, the Mississippi reversing itself, flowing toward the north.

Radiating tremors tumbled homesteaders from their beds in neighboring Kentucky and shook church bells in Charleston, South Carolina. Aftershocks continued for months, and two more major temblors shook the Earth again on January 23 and February 7, 1812, finishing off what the December quake had not destroyed and rattling windows in Montreal, a thousand miles away. By the time the entire episode was over, the course of the Mississippi had been changed in many places, and a new landscape of lakes and ridges had been sculpted. Entire towns had disappeared.

At the beginning of the nineteenth century all this was a puzzlement; when and where earthquakes might occur was anybody's guess. According to Jake Page, a science writer, and Charles Officer, a geologist, the scientists of the day had only the faintest idea that earthquakes might be associated with volcanoes or tectonic forces. They had no way of making quantitative records of geologic disturbances, and they knew nothing of the Earth's interior. To those who relied on guesswork and quasi-scientific analogy, earthquakes were traceable to such factors as unfavorable wind conditions, electrical disturbances, and the natural wrinkling of the Earth's cooling crust. To the pious, earthquakes were acts of divine retribution--though why Missouri deserved God's wrath any more than Washington, D.C., or New York City was, then as now, a theological enigma.

Page and Officer take the New Madrid quake as a point of departure for their genial history of modern earthquake science. Seismographs were a key development: a host of clever recording devices were introduced by British, Japanese, and Italian inventors in the mid 1800s. The infant science of seismology made it possible to listen to the "sound" of Earth's interior in response to temblors, just as you call tell whether a tree is hollow by the sound it makes when you tap on its trunk. In time, seismograph recordings enabled geologists to determine that Earth has a dense core surrounded by a slowly flowing mantle and a thin outer crust.

Seismology also led to the mapping of earthquakes all over the planet, and thus to the realization that some regions--the edges of the Pacific Ocean, for instance--are more prone to quakes than others. By the middle of the twentieth century such earthquake-prone zones were recognized as the intersections of tectonic plates, huge rafts of crustal material that float on the mantle and jostle each other ponderously, like giant floes in packs of sea ice. Most earthquakes came to be understood as a natural consequence of the sticking and sudden slippage of crustal plates in contact with each other, the fitful adjustments of continents in motion.

The New Madrid earthquakes, however, remained strange and puzzling, because they were centered far from the margins of tectonic plates: half a continent away from the San Andreas fault to the west, half a continent and half all ocean away from the Mid-Atlantic Ridge to the cast. Page and Officer explain how investigators working in the New Madrid area during the past decade have located a fault, known as the Reelfoot Rift, inside the crust, buried several kilometers deep beneath the sediment of an ancient inland sea and, overlying that, the deposits of the Mississippi River and its tributaries. It was the sides of this deep crack that slipped in 1811. Aftershocks continued for several years, and small earthquakes still waggle seismographs in the region.

So when, exactly, is the next "big one" due to hit the nation's midsection? On this point Page and Officer judiciously demur. In spite of two centuries' worth of increasing seismic savvy, earthquake prediction remains almost as much a magic art as it was in 1811. Still, if I were planning a move to Missouri, I wouldn't buy a penthouse condo, no way, no matter how attractive the price.

LAURENCE A. MARSCHALL, author of The Supernova Story, is the W.K.T. Sahm professor of physics at Gettysburg College in Pennsylvania, and director of Project CLEA, which produces widely used simulation software for education in astronomy.