The very massive, and frightening series of New Madrid quakes 200 years ago can happen again. If it does, St. Louis will not be a happy place. However, I have read other reports that suggest that the really bad ones happen there more on a 400 year schedule. Don’t remember where I saw that, but have been interested in NM for years. Caracas, Venezuela had a severe quake in that period that killed 20,000.
The prob’ with quakes and eruptions is, they have no schedule. Same can be said for large impacts from space. They just happen when they happen. :’)
There’s always a lot of talk about how CMEs and low-altitude nuclear explosions could ruin our electronics-dense civilization. A really large impact from space really could do that. The EMP from that would probably do the job.