Recent Midwest Quakes Called Aftershocks from 1800s

Each cross marks an earthquake recorded in the New Madrid seismic zone since 1974


The small earthquakes that sporadically rattle the central United States may actually be aftershocks from a few extremely large quakes that occurred in the region almost 200 years ago, according to a new study

The New Madrid Earthquakes, which struck between December 1811 and February 1812, are some of the strongest seismic events ever to occur in the contiguous United States in recorded history. The largest quake is estimated to have been 8.0 in magnitude and was powerful enough to temporarily make the Mississippi River flow backwards. The heart of the seismic activity was near the town of New Madrid, Missouri, close to the Kentucky and Tennessee borders.

The town has shaken with numerous earthquakes since, from tiny ones that don't cause much of a stir, to moderate sized ones, such as a 5.2 quake in 2008.

...The paper, which was a collaboration between researchers at Northwestern and the University of Missouri-Columbia, will be published in the Nov. 5 issue of the journal Nature. CONTINUE