The New Madrid Earthquakes – A Warning From History
By MARK DUNPHY
Sat Oct 15,2011
Earthquakes – and large ones at that – threaten to shake residents and buildings of the central and eastern United States, a reality that scientists, emergency responders and others hope to drive home during the bicentennial of the 1811 and 1812 New Madrid earthquakes.
Scientific presentations and discussions about these historic events and recent major earthquakes conclude today at the annual Seismological Society of America Meeting in Memphis, Tennessee.
During 1811-12, the central Mississippi River Valley was violently shaken by a series of three earthquakes above a magnitude 7, and up to 200 aftershocks between magnitude 4 and 7.
A similar risk exists today in the New Madrid seismic zone, which threatens Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri and Tennessee. Recent projections by the U.S. Geological Survey place the likelihood of a magnitude 6 or higher earthquake at about 25-50 percent over the next few decades, whereas a magnitude 7 or higher has a 10 percent chance of occurring.
With large cities like Memphis, St. Louis, and Nashville well within range of a large-scale New Madrid earthquake, understanding the science of earthquakes and the area’s geologic history helps communities prepare for earthquake hazards and prevent them from becoming catastrophes.