Photo: New Madrid, Mo. Picture and story courtosy of USGS
Scientists have finally figured out what might have caused a series of devastating earthquakes that struck the Midwest nearly 200 years ago at a set of faults that have confused geologists for a long time.
And the results suggest the region, still seismically active today, is going to keep shaking for a long time, and another big one will hit on the same 500-year cycle that has rocked the Heartland for as far back as records, legends and memory serve.
The largest of three or four big seismic events that stretched from December 1811 to February 1812 is called the New Madrid Earthquake and had an estimated 8.0 magnitude, strong enough to cause the nearby Mississippi River to temporarily flow backward. Its epicenter was in the town of New Madrid in southeast Missouri, near the Kentucky and Tennessee state lines. Hundreds of aftershocks followed for several years.
The damage from the New Madrid quake was bad enough in the early 19th century—half of the town was destroyed, but with many more people and buildings now in the area, a similar event in the region today would be devastating, seismologists and engineers agree.
More Quakes to comeFYI: The New Madrid Earthquake of 1811
Shortly after 2 o'clock on the morning of December 16, 1811, the Mississippi River valley was convulsed by an earthquake so severe that it awakened people in cities as distant at Pittsburgh, Pennsylvania, and Norfolk, Virginia. This shock inaugurated what must have been the most frightening sequence of earthquakes ever to occur in the United States. Intermittent strong shaking continued through March 1812 and aftershocks strong enough to be felt occurred through the year 1817. The initial earthquake of December 16 was followed by two other principal shocks, one on January 23, 1812, and the other on February 7, 1812. Judging from newspaper accounts of damage to buildings, the February 7 earthquake was the biggest of the three. Photo:Trees tilted by New Madrid earthquake, Chickasaw bluffs east side of Reelfoot Lake. Note twist of trees into upright position.
[Picture courtesy of USGS]
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