A River Runs Backwards: The 1811 Quake

Imagine a river, vast and powerful, suddenly deciding to defy gravity and flow in the opposite direction. While it sounds like something out of a tall tale, this extraordinary phenomenon actually occurred on the Mississippi River during the infamous New Madrid earthquakes of 1811-1812.

On December 16, 1811, the first in a series of devastating seismic events struck the central United States. This initial earthquake, and the subsequent powerful tremors that followed, dramatically reshaped the landscape of the Mississippi Valley.

The Earth Trembles

The New Madrid Seismic Zone, stretching through southeastern Missouri, northeastern Arkansas, and western Tennessee, is known for its seismic activity. However, the earthquakes of 1811-1812 were unlike any other recorded in North American history.

Three main shocks, all estimated to be between magnitude 7.0 and 8.0, occurred: the first on December 16, 1811; the second on January 23, 1812; and the most powerful on February 7, 1812. These quakes were felt across an enormous area, from Quebec to the Gulf of Mexico, causing widespread panic and destruction.

Mississippi's Moment of Reversal

The notion of the Mississippi River flowing backward is perhaps the most dramatic and widely recounted effect of these earthquakes. Eyewitness accounts from flatboatmen and settlers along the river confirmed this incredible event. During the most intense shaking, the river's normal southward flow was violently interrupted.

What caused this baffling reversal? The answer lies in the immense geological upheaval that accompanied the quakes. The powerful tremors caused significant land deformation, including both uplift and subsidence (sinking) of large tracts of land.

Specifically, a section of land about 15 miles south of the town of New Madrid experienced a sudden and dramatic uplift. This created a temporary damming effect on the river. Simultaneously, other areas along the riverbed subsided, forming new depressions and basins, most notably Reelfoot Lake in Tennessee.

• Uplift: A section of the riverbed rose, obstructing the natural flow.
• Subsidence: New depressions formed, creating a vacuum effect.
• Water Displacement: The massive volume of water, unable to continue its southward journey, rushed into these newly formed low-lying areas.

This rapid displacement of water caused a portion of the Mississippi River to flow northward, against its usual current, filling the sunken lands. This counter-current lasted for several hours, creating chaotic scenes of whirlpools and even temporary waterfalls in what was usually a placid stretch of river.

Lasting Impact and Legacy

The New Madrid earthquakes had a profound and lasting impact on the geography and ecology of the region. Besides the river reversal and the formation of Reelfoot Lake, new islands appeared, existing ones vanished, and vast areas of forest were submerged or toppled.

The sparsely populated nature of the area at the time meant that the death toll was relatively low. However, the psychological impact on the residents was immense. The sheer power of the earthquakes, combined with the inexplicable behavior of the mighty Mississippi, left an indelible mark on those who experienced it.

Today, the New Madrid Seismic Zone remains active. Geologists and seismologists continuously monitor the area, understanding that such powerful events, though rare, are a part of the Earth's dynamic processes. The story of the Mississippi River flowing backward serves as a vivid reminder of the incredible forces that lie beneath our feet.