1811-1812 New Madrid Earthquakes 一 When The Mississippi River Ran Backwards

The Mississippi River is one of the largest and most powerful rivers in the world. It flows more than 3,800 kilometers from Lake Itasca to the Gulf of Mexico and extends at one point to as many as 17 kilometers wide. And more than once in its history, as a result of natural disasters, it has actually flowed backward.

The first time the Mississippi reversed its flow was in 1811 and 1812, when a series of earthquakes originated in New Madrid, Missouri, and were felt as far away as Ohio and South Carolina. The soil beneath the Mississippi River rose, temporarily changing its to run backward for several hours.

The strange tectonic activity began at 2 a.m. on December 16, 1811; a strong tremor rocked the New Madrid region. No other earthquake has lasted long or produced as much evidence of the damage as the New Madrid earthquake. 

Three of the earthquakes are on the list of America's top earthquakes: the first major earthquake occurred in northeast Arkansas on December 16, 1811, at least three major aftershocks followed in the next 48 hours. The magnitude of this event is believed to be in the range of 6.7–8.1.

The second major earthquake in this series occurred in Missouri Bootheel on January 23, 1812, with an estimated magnitude of 6.8–7.8, and the third major earthquake occurred in New Madrid, Missouri, on 7 February 1812, with a magnitude of approximately 7.0–8.8 on the Richter scale. This tremor literally struck people off their feet, and many people experienced nausea from the vast rolling of the earth.

The third quake, which matched or even exceeded the first in strength, caused the Mississippi River to flow backward for several hours.

The series of disruptions that history has uniquely dubbed the New Madrid Earthquake has left its mark on more than two dozen states and territories. Several towns were destroyed, large trees snapped in two. Sulfur leaked out of the underground pockets, and the river banks vanished, flooding thousands of acres of forest.

In fact, since 2005, the Mississippi has reversed the flow twice. The first time was during Hurricane Katrina when the flow was reversed and was astounding 4 meters higher than usual. However, the reverse flow of the river lasted only a relatively short time, only a few hours.

In 2012, the Mississippi ran backward again for an incredible 24 hours in the aftermath of Hurricane Isaac. The hurricane-force was so strong that the river started moving water at a rate of 5,200 cubic meters per second in the wrong direction.

Minor earthquakes have continued in recent decades. The United States Geological Survey (USGS) projections estimate a 7–10 percent chance of a New Madrid earthquake of magnitude comparable to one of the 1811–12 quakes over the next 50 years and a 25–40 percent chance of a magnitude 6.0 quake at the same time.