The worst series of earthquakes in US history occurred in New Madrid, MO in 1811.
They’re projected to have been in the 9.o-9.1 range. The flow of the Mississippi River was reversed for a time and the channel was changed. Geysers of sand shot hundreds of feet into the air from huge holes that opened up in the ground.
Churchbells rang and windows cracked in Cleveland, Pittsburgh, and Buffalo from the shock.
If one were to hit the Midwest region there today of such a magnitude, St Louis, Memphis, and Louisville would be destroyed. And you know Midwestern cities do not have the architectural and structural engineering earthquake resistance that West Coast buildings must have.
San Francisco in 1906 and Anchorage in 1964 would pale in comparison.
That part of Indiana is on the northern edge of the New Madrid fault system.
If this was ever believed, it was a long, long time ago.
The latest scholarship puts the biggest of the New Madrid 1811-1812 earthquakes no larger than magnitude 7.5.