What if this happened to the Mississippi River?

 

I was interested to read that an ancient course of the Ganges River in India, some 2,500 years old, has been discovered.

Earthquakes, caused by the shifting of Earth’s tectonic plates, have the potential to transform the face of the world. Now, for the first time, scientists have evidence that earthquakes can reroute rivers: It happened to the Ganges River 2,500 years ago.

. . .

In a July 2016 study, Dr. Michael Steckler ... had previously reconstructed the tectonic plate movements — gigantic slowly moving pieces of Earth’s crust and uppermost mantle — that account for earthquakes experienced in the Ganges Delta.

His models showed that the likely source of earthquakes in the region is more than 100 miles (160 kilometers) away from the sand volcanoes that Chamberlain and her colleagues found. Based on the large size of the sand volcanoes, the quake must have been at least a 7 or an 8 magnitude — approaching the size of the Great 1906 San Francisco earthquake.

. . .

About 50 miles (85 kilometers) away from the sand volcanoes, the scientists also found a large river channel that filled with mud at roughly the same time. This finding indicates that 2,500 years ago, the course of the river dramatically changed. The proximity of these events in both time and space suggests that a massive earthquake 2,500 years ago is the cause of this rerouting of the Ganges.

There's more at the link.

The now-demonstrated fact that a major earthquake can change the course of even a huge river like the Ganges, moving it 50 to 100 miles away from its previous course, made me think hard.  I don't know that we've ever seen the like in North America;  most of our rivers have changed course through a combination of erosion and silting (as far as I know, anyway).  However, what might happen if something like the New Madrid Fault let go in a big way?

Earthquakes that occur in the New Madrid Seismic Zone potentially threaten parts of seven American states: Illinois, Missouri, Arkansas, Kentucky, Tennessee, and to a lesser extent Mississippi and Indiana.

The 150-mile (240 km)-long seismic zone, which extends into five states, stretches southward from Cairo, Illinois; through Hayti, Caruthersville, and New Madrid in Missouri; through Blytheville into Marked Tree in Arkansas. It also covers a part of West Tennessee near Reelfoot Lake, extending southeast into Dyersburg. It is southwest of the Wabash Valley Seismic Zone.

Again, more at the link.

What's more, the New Madrid Fault runs slap bang underneath the Mississippi River.  If it really let go, it could easily produce an earthquake with a magnitude of 7 to 8 - it already has in the not too distant past.  If it were big enough, and lasted for long enough, what might that do to the biggest river on our continent?  If a waterway that big were to be displaced by 50 to 100 miles east or west, how much of our economy, our cities and our population would it take with it?  And what would happen to anything in the way?

It's a fascinating subject for speculation.  I wonder if it might make an interesting novel - perhaps set in older times, around the Civil War or Wild West period, as alternate history?  There were powerful earthquakes along the Fault in 1811-12.  What if they were repeated, say, 60 or 70 years later, at even greater intensity?

Hmmm . . .

Peter