When Arkansas Shakes & Quakes

“…we were visited by a violent shock of an earthquake, accompanied by a very awful noise resembling loud but distant thunder.” – Eliza Bryan, New Madrid, MO

“Many acres of land in a body sunk to a level with the surface of the river, and some much lower leaving only the tops of the trees above water.” – David Bedinger, Mississippi River barge passenger

“Of about a dozen houses and cabins which I saw, not one was standing, all was either entirely prostrated or nearly over-turned, and wrecked in a miserable manner, the surface of the ground cracked and fractured in every direction.” – James McBride, merchant transporting goods on the Mississippi River

[After the earthquake] it was proposed that all should kneel, and engage in supplicating God’s mercy, and all simultaneously, Catholics and Protestants, knelt and offered solemn prayer to their Creator.” – John Shaw, Tywappety Hill (30 miles north of New Madrid)

These are a few of the many accounts of a series of earthquakes that shook the New Madrid Seismic Zone (NMSZ) from December 1811 to February 1812.  With a magnitude of 7.0 or higher, these quakes were some of the largest in American history and actually made the Mississippi River run backward.

The New Madrid Seismic Zone, sometimes called the New Madrid Fault, encompasses five states including Illinois, Missouri, Kentucky, Tennessee and Arkansas. As Arkansans, earthquake awareness is probably not foremost in our minds, but maybe it should be.

The first known written account of an earthquake experienced in the NMSZ was on Christmas Day, 1699, by a French missionary travelling with explorers. The next series of quakes was the 1811-1812 event. Modern seismic activity includes a November 9, 1968 event that registered at 5.4 magnitude and was felt in 23 states, and over the last 15 years many quakes ranging from 2.0 to 4.7 magnitude have been felt in the zone.

A considerable amount of time and money have been spent to predict future fault activity. Studies conducted in 2008 and 2009 by the United States Emergency Management Agency reported that a serious earthquake in the New Madrid Seismic Zone could result in “the highest economic losses due to a natural disaster in the United States,” further predicting “widespread and catastrophic” damage across many states, including Arkansas.

According to the studies, a 7.7 magnitude earthquake would affect vital infrastructures including water distribution, and transportation systems. It’s estimated that the NMSZ would sustain damage to roughly 700,000 buildings, 7.2 million people would be displaced and over 3,000 lives lost.

What are the chances of this disastrous scenario? The United States Geological Survey believes there is a 7-10% chance of an earthquake the size of the 1811 quake within the next 50 years, and a 25-40% chance of a 6.0 magnitude within the same time period.

So now that we’ve talked about the history of the zone, potential destruction of a repeat of the 1811-1812 event and the chances of it happening, in the next issue of Saline County Lifestyles, we’ll share information from the Arkansas Department of Emergency Management about what to do in the event of a sizeable earthquake and what we can do to prepare. ν