Friday, Dec. 16, marks the 200th anniversary of the first of the New Madrid earthquakes, a series of large tremors centered in northeastern Arkansas and southeastern Missouri.
The earthquakes of 1811 and 1812 were so big, legend has it, they made the Mississippi River run backwards.
Seismologist Susan Hough of the U.S. Geological Survey in Pasadena, Calif., says that’s actually true – at least where the fault crosses underneath the river channel.