The New Madrid Seismic Zone has the potential to produce very large earthquakes. There was quite a bit of activity there early in the 1800’s.
I’ve read about the 1811/1812 quakes that were, what, in the 8.0 range? I’ve been fascinated by the New Madrid since the time when I was almost stationed at the old Blytheville (is that how it’s spelled?) AFB.
I’m guessing this is the Fortville. But that’s just a guess...I haven’t even looked at the details at all.