What would happen if a major earthquake hit the Midwest? It turns out one did – three, actually – exactly 200 years ago this month, with their epicenter in New Madrid, a frontier trading post in southeastern Missouri about 150 miles downriver from St. Louis.
A new report from AIR Worldwide risk modeling used the bicentennial of this rare "correlated triplet" event to explore what might happen if it were to reoccur today.
The first quake, magnitude 7.7, occurred Dec. 16, 1811. The second, a 7.5 jolt, hit Dec. 23. The third, again a 7.7, struck on Feb. 7, 1812.
The quakes wiped out New Madrid, caused significant damage to homes and structures in St. Louis and were felt as far away as Washington, D.C. They even caused church bells to ring in Charleston, S.C.
If the New Madrid quake were to hit today, the results would be far more calamitous. St. Louis, a jumping-off point for westward expansion with just 5,000 people back then, has a metro-area population of 2.9 million today. The surrounding regions, including Memphis, Tenn., Louisville, Ky., and Nashville, Tenn., would bring the number of those affected to 7.2 million.
According to the Mid-America Earthquake Center, a recurrence could result in 3,500 fatalities, 86,000 injuries and 2 million people in need of immediate shelter. Electric power, water, sewage and home fuel systems could be out for weeks and even months because roads, rail lines, bridges and river traffic up and down the Mississippi would be extensively disrupted.
AIR estimates that the total insured losses of such an event would be $110 billion. Add on another $4 billion in workers' compensation losses if such a quake were to occur during working hours.
Fortunately, the U.S. Geological Survey estimates that there is a 7 to 10 percent chance of a 7.0 magnitude quake hitting the Midwest within the next 50 years.
This year's 4.6 and 5.7 earthquakes in Oklahoma and the 5.8 quake in Mineral, Va., served as a reminder for many that most homeowners insurance policies do not cover earthquake damage. Data from those quakes is being included with the New Madrid studies in the new seismic hazard maps being prepared by USGS for 2013.
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