4 Lesser-Known Missouri Quake Faults Other than New Madrid

I've heard it said that you learn something new everyday. I don't feel like I live up to that standard, but I did learn something today that I did not know before and that's the fact that there are 4 lesser-known earthquake faults/regions in Missouri other than the infamous New Madrid Fault.

Since I really don't enjoy inspiring panic, I want you to know from the start that these lesser-known earthquake areas in Missouri aren't really something that the USGS is concerned about being a current threat for a major event. The New Madrid Fault is the main culprit that has the potential to mess up our lives in the near future. However, it is good to know about what other cracks in the ground in Missouri lie beneath our feet. Here are 4 non-New Madrid earthquake faults in Missouri:

1. Ste. Genevieve Fault Zone

• Runs in southeastern Missouri into southern Illinois
• Part of the broader ancient rift system beneath the region
• Can show minor seismic activity, but nothing like New Madrid

2. Commerce Geophysical Zone (or Lineament)

• Located in southeast Missouri near the Bootheel
• A buried structural feature tied to deep crustal weaknesses
• Not very active today, but it can influence where stress is released

3. St. Francois Mountains fault system

• Found in eastern Missouri (Ozarks region)
• These are some of the oldest exposed rocks in North America
• Faults here are mostly ancient Precambrian structures, now largely inactive

4. Reelfoot Rift (deep structure beneath the region)

• This is actually the larger ancient failed rift system that the New Madrid zone sits within
• Extends through parts of Missouri, Arkansas, Tennessee, and Kentucky
• The modern earthquakes in the region are related to stress reactivation inside this old rift

The best way I know to explain why it's good to know about these earthquake areas without being concerned about them is this. The St. Francois Mountains in Missouri are where ancient volcanoes used to be. Does that mean we're in for an eruption? Nope. They're dormant (or so I hope), but they are a part of the real history of Missouri. Same can be said of these earthquake faults and rifts. Are they a real part of Missouri geology? Yes, they are. Should you lose any sleep over their existence? No, you should not.