This was my final paper for HIST1790: North American Environmental History.  I decided to examine the historical accounts of the infamous New Madrid Earthquakes in Missouri in 1811-1812, largely because it complemented my interest in geology.

Convulsions of the Earth: The 1811-1812 New Madrid Earthquakes

Eliza Bryan awoke to the sound of thunder.  As she sat up, her house began to shake violently, knocking the thirty-one year old from her bed and toppling furniture as she crawled out of her room.  Clambering outside into the pitch blackness, distant booms from deep within the earth, reminiscent of heavy artillery, drowned out the cacophonous din of screaming neighbors, squawking birds, braying horses and mooing livestock.  Still unable to stand amidst the overwhelming shaking, Eliza heard nearby trees snap like twigs and the usually calm river roar angrily while a sulphurous vapor invaded her nostrils.  To the four hundred residents of New Madrid, Missouri, in the morning hours of December 16th, 1811, God’s wrath had come.

Numerous aftershocks followed the initial predawn earthquake.  The residents of New Madrid quickly fled to higher ground fearing the rising tide of the adjacent Mississippi would flood their riverside frontier town.  As the sun rose, the frazzled refugees noticed massive fissures, yards across and miles long, scarring the previously undisturbed farmland.  In some fields, geysers of sand and water erupted high into the air, leaving volcano-like cones of ejecta at their bases.  As darkness fell, flashes of light emanating from the earth preceded each new shock, confusing the already anxious populace.  The convulsions of the earth went on.  Over the next five months, two more powerful earthquakes—equal or greater in magnitude to the first—rocked the region, amidst thousands of smaller but still nerve-racking aftershocks.  Uplifted terrain during the last large event even managed to temporarily redirect the flow of the mighty Mississippi River, sending a huge wall of water backwards upstream.  Then, as suddenly as the quakes began, they stopped.

It comes as a surprise to most Americans that the largest earthquake to hit the lower forty-eight states in recorded history occurred in Missouri.  Based on eyewitness accounts and other evidence, seismologists estimate the three most powerful events during the 1811-1812 sequence measured above magnitude 8.0—beating out the 1994 Northridge (6.7), the 1989 Loma Prieta (6.9) and even the 1906 San Francisco (7.8) earthquakes.  Although scientists have thoroughly catalogued the ancient fault line underneath the Mississippi valley responsible, the hazard it poses and the moving eyewitness testimonies of frontier settlers like Eliza Bryan have receded from the public eye.  Neat parcels of tractable farmland, home to millions of Americans, now cover the once untamed wilderness in which pioneers founded New Madrid.  Dikes and dams control the flow of the Mississippi with hydraulic precision, farmers spread synthetic nitrogen fertilizers on genetically enhanced crops, and air conditioning provides relief even on the hottest summer days.  Humankind has domesticated the visible layers of nature, subduing them to prevent undesirable interruptions in derivable productivity.  Nevertheless, the invisible, subterranean nature of the land, manifest in the faults responsible for the devastating New Madrid earthquakes, has not changed.  This has been forgotten, resulting in a pervasive lack of preparedness for the inevitable future earthquakes beneath the Mississippi.  Thus, the anthropocentric concept of an entirely controlled, subjugated nature is a fallacy, for human beings live inevitably at the mercy of the earth.

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Nearly a billion years ago, the land today located in North America’s midwestern region belonged to a much larger continent known as Rodinia—appropriately derived from the Russian word for “motherland.”  Plumes of heat rising from the earth’s core created circulating convection cells, driving the imperceptibly slow but steady drift of the continental plates.  As millions of years passed, these forces pulled Rodinia apart, creating valley-like rifts where the supercontinent tore into smaller pieces.  In the piece now known as North America, a secondary rift developed extending from today’s Gulf of Mexico to the Missouri boot heel.  For reasons unknown to geologists, this rift stopped separating a few million years later, leaving the proto-North American continent with a geologic scar, called an aulacogen, where it would have torn.  Even after hundreds of millions of years when all the earth’s continents rejoined as Pangaea and again broke apart, North America still bore this scar.  It is no coincidence that the modern Mississippi River follows the path of this zone of weakness as it travels from north to south.  As a consequence, a three-mile thick layer of riverbed sediment now rests on top of the rift’s original faults, hiding the instability deep underground.

Most earthquakes occur as two wholly separate continental plates slide against, across, or under one another.  The San Andreas fault in California, for example, exists at the junction of the North American and Pacific plates.  As tectonic pressure builds, the traction between plates at the fault restrains movement, accumulating stress.  After time passes, this stress eventually exceeds the restraining power of friction, causing the plates to suddenly reposition themselves in a jolt—an earthquake.  In the case of the aulacogen underneath the Mississippi valley, no nearby plate boundary exists to build stress.  However, the New Madrid seismic zone feels tectonic pressure from the faraway mid-Atlantic ridge, where it pushes the entire North American continent away from Africa and Europe and into the Pacific.  The New Madrid fault exists between the point where this pressure is applied in the Atlantic and where it is released in the Pacific.  As a result, this zone of weakness periodically fails like the buckling of a car’s supple crumple zone when it hits a stationary object.

For these reasons, the essence of the cause of the New Madrid earthquakes is rooted in geologic happenstance a billion years before present.  Cold as though it may seem, the damage and destruction wrought by the 1811-1812 events essentially occurred as a result of chance.  A comparable coincidence is the fortuitous discovery by early humans of a peculiarly mutated teosinte plant in prehistoric Mexico, the ancestor of modern maize.  Without such a discovery, Zea mays, the staple on which the American diet is based, would not have been cultivated.  On a more geologic timescale, another equally fluky event is the deposition of fertile soil in the midwestern United States during the retreat of glaciers at the start of the Pleistocene era.  Without these twenty-foot layers of soil, the productivity of American farms would be severely diminished.  These chance events entail consequences that range from bounteous to destructive, but have all profoundly affected the course of environmental history.

The fact that the New Madrid seismic zone exists far from an active tectonic plate boundary has another consequence.  The edges of tectonic plates, called orogens, are younger, warmer and more geologically active than land in the center of tectonic plates, called cratons.  In an earthquake, the softer, warmer rock and faulting in orogens helps attenuate the strength of seismic waves, reducing the area affected.  In the cooler, older and less faulted rock of cratons, seismic waves travel farther without attenuation, affecting a much larger area.  An analogy for this variation is the difference between hitting a hammer on wood versus metal.  The fibrous and soft nature of wood absorbs much of the impact, while the uniform molecular structure of metal absorbs little.  As a result of this reduced attenuation rate, witnesses felt vibration from the New Madrid earthquakes thousands of miles away.  Church bells rang spontaneously in Boston, books fell off library shelves in New York City, and chimneys in Washington D.C. toppled over.  By contrast, earthquakes in California are rarely felt more than a few hundred miles away at most.  Today, the New Madrid seismic zone poses a greater hazard to life and property, compared to a quake of similar magnitude in California, as a result of this larger area of effect.

In addition to affecting a greater area, the soils on which major midwestern cities like Memphis, Nashville and St. Louis rest constitute a significant hazard to the stability of structures.  Compared to Californian soils, very thick sediments underlie the Mississippi river valley.  This layer of topsoil effectively amplifies the shaking of an earthquake.  As seismic waves cross the boundary between from bedrock to soil, their propagation speed decreases.  This compresses the entire energy of the waveform into a shorter wavelength, though the period of time between crests and troughs remains the same.  The combined effect of these processes dramatically increases the amplitude of the wave, in turn increasing the degree of shaking felt at the surface.  This phenomenon, called local sediment amplification, also occurs to a greater extent in thick midwestern soils than in California.

The New Madrid fault system also has the potential to incur especially severe damage as a result of subsidence due to the saturation of soil.  Although California’s Central Valley represents a broad, flat watershed, it pales in comparison to the size and water content of the Mississippi River valley.  This larger area of more saturated soils increases the hazard of a phenomenon called soil liquefaction.  During an earthquake, ground shaking compacts soils, increasing the pressure on water particles interspersed between the mineral grains in sands, silts and clays.  In fully saturated soils, water under pressure has nowhere to flow.  In some cases, the pressure can be so great that the weight of overlying material is  effectively transferred from the skeleton of sand grains to the matrix of water particles.  Once this occurs, the soil undergoes liquefaction, where it behaves like a liquid instead of a solid.  Even a slight gradient causes the land to flow.  This resulted in many square miles of Mississippi riverbank washing away in 1811-1812.  Today, most subsidence-related damage in cities during earthquakes occurs as a result of liquefaction, especially due to the proximity of most cities to rivers where the necessary beds of sand and silt exist.  Liquefaction exacerbates the earthquake hazard in the modern New Madrid area, where thick sedimentary layers underlie nearly all buildings, highways and bridges.

During the 1811-1812 earthquakes, the combination of liquefaction and powerful seismic waves caused the earth to undulate like waves of water, rippling across the land’s surface with three-foot crests.  In some places, these waves burst into great geysers, blowing sand, water, and chunks of coal high into the air.  These “sand volcanoes” or”sand blows” occur when water-impermeable layers block the release of pressure, forcing a more concentrated stream up through fissures.  As the pressure is released, these eruptions deposit feet-thick cones of ejecta at their bases in a manner similar to volcanoes.  Recently, geologists have used these sand blows to investigate the possibility of other, earlier earthquakes occurring in the area.  These researchers, known as paleoseismologists, discovered multiple buried sand volcanoes in the New Madrid area.  Using radiocarbon dating and other methods, they have determined that earthquakes similar in magnitude to the 1811-1812 events occurred around 1450, 900, and 300 CE. Based on these dates, geophysicists estimate the average interval between events to be 450 years.  Clearly, the New Madrid earthquakes were not isolated events, but episodes in a recurring geologic cycle.  Scientists estimate a 90% probability of a magnitude 6.0 or greater tremor occurring before 2035.  The same study estimates a 5% chance of a magnitude 8.3 earthquake—on par with the 1811-1812 quakes—in the same time period.

On top of bizarre sand blows, some witnesses saw flashes of light emanating from the earth with each shock, similar in nature to the flash and boom of thunder and lightning.  To this day, scientists do not agree on the source of these “earthquake lights.”  However, some geophysicists theorize a phenomenon known as the piezoelectric effect may be responsible for such discharges.  Due to peculiarities in their molecular structure, certain materials generate an electric current in response to the application of physical pressure.  Examples of such substances include a number of crystalline minerals like quartz, certain ceramics, and even bone.  Today, many appliances employ the piezoelectric effect, from electric cigarette lighters to camera lenses to guitar pickups, though the amount of current generated in these circumstances is miniscule.  When a huge section of land rich in quartz undergoes compressive stress in an earthquake, a massive piezoelectric current could be generated, ionizing particles of air in a process similar to lightning.  However, few scientists have conducted research regarding earthquake lights, and its attribution to piezoelectricity remains speculative at best.

Perhaps the most astonishing event of the 1811-1812 earthquakes took place during the third and final major seismic event: the Mississippi flowing backwards.  The length of fault that ruptured during the February 11th earthquake lies in an east-west orientation, crossing the river perpendicularly.  The manner in which it broke instantly forced a long section of land upwards by several yards.  This uplifted riverbed displaced a large enough volume of water, creating a gradient opposite the normal direction of flow.  A massive wave resulted, spreading northwards thirty feet above the river’s normal level.  In one account, the wave carried a fleet of three small flatboats upriver for over a mile.  As the steepness of the gradient diminished, the river returned to its normal direction of flow, though a new length of rapids and waterfalls now existed at the edge fault.

In the aftermath of the New Madrid earthquakes, many residents returned to their homes to find that their land had literally washed away—the Mississippi now flowed where their houses once stood.  Many appealed to the government of Missouri territory for aid.  Governor William Clark, later famous for his exploration of the American West with Meriwether Lewis, wrote to the fledging United States Congress seeking aid:

Whereas the Catalogue of miseries and afflictions, with which it has pleased the Supreme Being of the Universe to visit the inhabitants of the earth there are none more truly awful and destructive than Earthquakes. . . The inhabitants of the late District now County of New Madrid, in this Territory, have lately been visited with several calamities of this kind, which have deluged large portions of their country and involved in the greatest distress many families, whilst others have been entirely ruined. . .In the opinion of the said General Assembly provisions ought to be made by law for or cashiered to the said inhabitants relief, either out of the public fund or in some other way as may can meet to the cost demand availability of the General Government.

This entreaty marks the one of the earliest known requests for disaster relief from the federal government.  However, Clark’s letter differs from modern please for disaster relief through the Federal Emergency Management Agency.  Instead of seeking humanitarian aid, the inhabitants merely desired a reapportionment of lost land.  In response, the Committee on Public Lands granted 160 acre lots to any who “had been materially injured by earthquakes.”  If similar seismic activity took place today where millions of people (instead of thousands) now live, the governor would surely make more exigent requests amidst the greater destruction.

The New Madrid earthquakes entailed a number of unusual geologic features and phenomena, many of which occurred purely by chance.  From ancient fault lines to low seismic attenuation, local sediment amplification, soil liquefaction, sand volcanoes, piezoelectric lights and retrograde currents, the 1811-1812 events ran the gamut from strange to ludicrous.  It is unsurprising that, in the year following the apocalyptic quakes, regional membership in the Methodist Church jumped from thirty to forty-five thousand.  Even today, such a symphony of terrors would boggle the mind of believers and non-believers alike.

Through another twist of fate, these events coincided with a turning point in the area’s environmental history.  Had the earthquakes occurred a few decades earlier, their study might fall strictly under the discipline of paleoseismology with far fewer details documented to enrich the geologic and historic record.  On the other hand, had the earthquakes occurred a few decades later, people would have sustained much greater damage to life and property.  This coincidence is a blessing and a curse.  Geologists are blessed for the insight into the nature of the deep earth and the associated hazards without paying as steep a human price.  They are simultaneously cursed in that the relatively low death toll diminishes the notability of New Madrid seismic zone, ironically hampering the earthquake preparedness effort in the area.

Since the early 1800s, the town of New Madrid has grown into a city of over four thousand residents.  Millions of acres of corn, soybeans, and grazing land now cover the landscape where dense wilderness forests once stood.  A system of dikes and levies now control the flow and flooding of the Mississippi River.  Eleven million Americans now reside on the land where only a few thousand inhabitants lived in 1811.  Despite this domestication of the land and water, the New Madrid faults have not changed.  The New Madrid seismic zone lies within 150 miles of the St. Louis, Memphis and Nashville metropolitan areas, threatening these cities with the same degree of devastation which eyewitnesses had once attributed to the wrath of God.  Unfortunately, the populace has taken few precautions to protect themselves.  Entire cities rest on sediments susceptible to liquefaction.  Buildings consist of brick and mortar frames that easily crumble under the stress of seismic waves.  Highways and bridges, already deteriorating from disrepair, would fracture and collapse from such violent shaking.  Much of the country’s natural gas and electricity infrastructure, on which the Eastern seaboard depends, passes through the area in vulnerable housings.  Although the United States Geologic Survey has undertaken an effort to inform residents and government officials of the harm, only a few paltry safeguards exist.  Actuarial studies estimate the damage from an event equal to the 1811-1812 quakes exceeding $200 billion dollars.

This lack of preparedness can be attributed to two main factors.  The more obvious factor is the attitude of government officials and the prolonged interval of time between earthquakes at New Madrid.  In the United States, safety-related public policy tends to develop reactively to undesired events, not preventatively.  Laws concerning pesticides exemplify this paradigm, as no legislation concerning the health hazards of these chemicals existed before Rachel Carson’s Silent Spring raised public awareness.  In the case of New Madrid, the dearth of recent damaging seismic events has stymied earthquake preparedness efforts that appear unnecessary and wasteful to lawmakers, who understandably perceive earthquakes as a far-off threat.

On a less tangible level, a deluded perception of nature also impedes efforts to prepare for future earthquakes.  From the perspective of the average American, humans have fully domesticated the nature of the New Madrid region to the point of total control.  This perspective fails to take into account the underlying processes which govern the nature of the earth manifest in the ancient fault system beneath the Mississippi.  This ignorance does not, however, deserve blame.  The convulsions of the earth have not returned to the area, and no unnecessary loss of life or property has occurred.  Nevertheless, all scientific expertise suggests that in the future, the earth beneath Mississippi Valley will violently tremble again.  Thus, the increased hazards of the New Madrid area merit a more concerted preparatory effort, such that when the earthquakes return, we will be ready.

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Bibliography

• John Bradbury, Travels in the interior of America, in the years 1809, 1810, and 1811 (London: Sherwood, Neely and Jones, 1817), 196-209.
• Letter by Eliza Bryan to Lorenzo Dow, “New Madrid, Territory of Missouri, March 22, 1816,” in Lorenzo Dow, History of Cosmopolite; or the Four Volumes of the Rev. Lorenzo Dow’s Journal (Wheeling, VA: Joshua Martin, 1849), 344-346.
• Rachel Carson, Silent Spring (New York: Houghton Mifflin, 1962).
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• Ted Steinberg, Down to Earth: Nature’s Role in American History (New York: Oxford University Press, 2009).
• “Appliction of Missouri for Further Relief to the Sufferers by Earthquakes in New Madrid County in that state,” American State Papers: Public Lands, Vol. 4, 881-882.