Memphis would be devastated by a quake of this magnitude...
No doubt. Have you read his book? I’m reading it, hence my ping to him.
Any place that has old buildings or building codes that are not geared to withstanding earthquakes, would be devastated.
It has been 200 years since the great New Madrid quake series. While I have notice an every 200 years pattern to some earthquake and volcano events, I recently read that New Madrid research indicates a 500 year period for the really big ones. On the other hand, even a more modest one could cause serious damage with all the population/buildings now in the New Madrid/St. Louis area, especially given that there has been an upsurge in modest quakes in surrounding areas like Arkansas.
If I lived in that area. I would store lots of water in used milk jugs and other containers somewhere that nothing would fall on them. I would also have emergency bag(s) near the front or back door ready for a quick exit. Also boxes of canned and plastic bottled foodstuffs where it could easily be reached if there was damage to my home and I had to camp out or go live with friends and couldn’t go back inside safely. Better safe than sorry. Think of the poor folks after Hurricane Andrew.