No doubt you’ve heard about the giant earthquake known as the “Big One” that is supposed to hit California at some point in the future. Geologists are convinced that someday the San Andreas Fault, which runs through the middle of most of California, will someday move so much that it will cause a massive earthquake that could send much of Los Angeles, or San Francisco, or both, into the ocean. Since the 1970s, there have been numerous big budget films made about this scenario, but as of today, all of these movies remain science fiction.

Thankfully!

But if you think that the San Andreas Fault zone presents the only major serious earthquake threat to the United States, you’re wrong. Located in the southeastern Missouri bootheel is a small town named New Madrid. The town itself is quaint and unassuming, an architectural and cultural blend of the Midwest and Southeast. But what lies beneath the ground could potentially kill millions.

Second only to the San Andreas Fault in size, the New Madrid Seismic Zone runs through the boot-heel north into the southern tip of Illinois and south into northeastern Arkansas for about 150 miles, which includes parts of the states of Missouri, Kentucky, Illinois, and Tennessee. In modern times, the rumblings of the New Madrid zone haven’t been nearly as remarkable compared to what has taken place in California, but it has quite a destructive history.

In December of 1811 and January of 1812, the New Madrid Fault Line erupted in a series of powerful earthquakes that changed the course of the Mississippi River. Although there were no instruments to gauge the strength of the earthquakes, geologists believe that the first quake measured 8.0 “moment magnitude,” which would put it into the “Big One” category.

The quakes were felt hundreds of miles away and created the large northwest Tennessee lake, Reelfoot Lake.

The quakes even had a major impact on the history of the early American republic.

Many of the American Indian tribes of the region (now recognized as the states of Illinois and Indiana) took the quakes as a sign that they should align with the British against the Americans in the War of 1812. If you don’t know how that one turned out, the Americans won. So maybe it was actually a sign for them to stay out of the war.

Fortunately, since that part of America was still the frontier, the quakes caused relatively few deaths. But that wouldn’t be the case today.

Seismologists and geologists are conflicted over whether or not a “Big One” will happen in the New Madrid zone. However, all agree that if one were to happen it would be devastating for the region. Since the New Madrid zone is under the Mississippi River, it would cause major flooding, disrupt barge traffic, and destroy the handful of bridges between St. Louis and Memphis. The quake would also damage those two cities, potentially causing immense destruction and loss of life in Memphis.

So if you’re living in the New Madrid zone or planning to move there, just take a cue from lifelong Californians—always be ready for an earthquake, but don’t live in fear of the “Big One.”