Thursday, December 16, 2010

Shaky Story

One hundred and ninety-nine years ago today, two terrible temblors rocked the Middle Mississippi River Valley. Those two approximately 7.5 to 8.0 Richter Scale jolts, and the two similarly-scaled subsequent quakes over the next two months, were the largest and widest-felt seismic events in recorded history on the North American continent. Whereas the 1909 San Francisco Earthquake--on which the sure-to-come repeat of which popular culture focuses dreadful anticipation--was felt over a roughly 6000 square mile area, the 1811/1812 New Madrid quakes were felt, owing to much different geography, over an area encompassing an incredible one million square miles.

The effects, and the distance to which effects extended, of those four earthquakes and the hundreds of attendant aftershocks were, quite frankly, unbelievable. Epicentered along a line extending from extreme northeastern Arkansas into the Missouri boot heel, the major jolts were felt as far away as the Eastern Seaboard. Straining credulity, some accounts maintain that the shocks were strong enough not only to be felt as far away as Boston and Toronto, but that they were strong enough at that extreme range to even ring church bells in those towns! Damage to dwellings was reported as far away as South Carolina and Ohio. In the region of the epicenters, population was very sparse. Yet, what few eyewitness accounts that survive recount scenes of unimaginable destruction. One such eyewitness, Eliza Bryan, a resident of the tiny village of New Madrid, wrote:

"On the 16th of December, 1811, about two o'clock, a.m., we were visited by a violent shock of an earthquake, accompanied by a very awful noise resembling loud but distant thunder, but more hoarse and vibrating, which was followed in a few minutes by the complete saturation of the atmosphere, with sulphurious vapor, causing total darkness. The screams of the affrighted inhabitants running to and fro, not knowing where to go, or what to do — the cries of the fowls and beasts of every species — the cracking of trees falling, and the roaring of the Mississippi — the current of which was retrograde for a few minutes, owing as is supposed, to an irruption in its bed — formed a scene truly horrible."

The quakes significantly altered the very geography of the region. Soil liquefaction and land subsidence created vast swamps and lakes where once stood virgin forests. Not only were there reports of the Mississippi River flowing backwards, but eyewitness accounts tell us that an upheaval under the bed of the river actually created a waterfall at one point that persisted for several days before the mighty current carved away the disruption in the riverbed. Whole islands in the Mississippi River subsided and disappeared. Huge tracts of timber up and down the river were uprooted and washed away from the shoreline, forming giant log jams that impeded boat traffic on the primary trade artery for months.

From their study of the New Madrid Seismic Zone (NMSZ), geologists tell us that earthquakes of the magnitude of those in 1811/12 strike the zone every 200 to 500 years. Current forecasts, as inexact as the science of earthquake prediction is, are that there is a roughly 1 in 15 chance of a 7.5 quake in the zone in the next 20 years. Of course, the chances of a repeat of such a quake increase with time. The chances of a lesser, but significantly damaging nonetheless, 6.0 in the very near future are much higher.

How destructive would a major magnitude quake in the region be today? In 2008, the U.S. Federal Emergency Management Agency (FEMA) reported that a large earthquake in the NMSZ might cause "the highest economic losses due to a natural disaster in the United States," with "widespread and catastrophic" damage across a zone encompassing all or parts of the states of Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri and Tennessee. The major metropolitan area adjacent to the NMSZ is Memphis, TN, a city which did not exist in 1811 and is today the home of 1.5 million people. Memphis is a major redistribution center--the home of FedEx and a transportation hub for dozens of retail, supermarket, and construction supply chains. The FEMA report warned that a 7.7 magnitude quake or greater would cause damage to tens of thousands of structures affecting water distribution, transportation systems, and other vital infrastructure.

A major earthquake in the NMSZ would devastate Memphis, destroy the rail and road bridges across the Mississippi River there and probably seriously damage bridges as far south as Greenville, Mississippi and as far north as St. Louis. Highway and road bridges of every type would fall--the rubble of highway and rail overpasses and bridges over water courses would create obstacles to all but foot traffic. Pavement throughout the region would buckle, split, crack, and subside to make almost all vehicular traffic impossible. Nearly every building in Memphis and for 100 miles in every direction would be severely damaged if not destroyed. Buildings not flattened by shaking would burn in uncontrollable fires fed by thousands of gas pipeline breaks and other flammable releases. Those firefighting resources not themselves incapacitated by the quake's effects would be overwhelmed immediately, unable to respond to but a tiny fraction of the fires that could easily unite in an all consuming firestorm.

Casualties in the hundreds of thousands would overwhelm medical facilities, except that no medical facilities would have withstood the quake. And even if any had survived, their staffs would be limited by their own casualties and hampered by a lack of electricity and water.

If New Orleans' Katrina experience is any indication, police protection would break down completely as most law enforcement personnel would either themselves be casualties or decide to look after themselves and their own rather than attempt to maintain order in an increasingly desperate and violent situation.

The two-day wait for outside aid Katrina survivors experienced would pale in comparison to the weeks it would take for help to work its way into the destruction zone of a major NMSZ quake. Long before any appreciable help could arrive, survivors would have stripped and looted any surviving food stocks and begun to flee the destruction zone. Thousands would die fighting for food and water and in obstacle-filled flight to reach unaffected areas. Diseases, deadly and highly contagious cholera for example, would follow in rampant rapidity on the heels of the total collapse of sanitation and potable water infrastructure. Communities outside of the destruction zone, whose access to resources will be significantly affected by the quake's disruption of transportation and communications infrastructure across much of the middle of the nation, will face unprecedented challenges and choices as they first struggle to help the initial survivors to arrive on their doorsteps, and then find themselves in danger of violence from desperate throngs of hungry and homeless.

Excerpts of the Colonel's novel in progress, which deals with Southern society in the aftermath of a future New Madrid quake, can be found at http://www.scribd.com/doc/44946106/Tallahatchie-Excerpt

The Colonel hopes he can complete it before the next quake hits.
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