Swarm of 8 Missouri Quakes this Week in New Madrid ‘Strike Zone’

I thought it had been a rather quiet week along the New Madrid Fault Zone in Missouri this week, but I learned that below the surface there has been a lot of activity. I found a swarm of 8 quakes in Missouri inside of the 'strike zone' of the New Madrid area.

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If you look at activity along Missouri's New Madrid Fault over the past 6 days, here's what you'll find. 8 rather small quakes were recorded by the USGS, but many were felt even though they were relatively small. This map looks insignificant.

It's when you enable the USGS "Hazard Zone" overlay that it gets interesting. You'll notice that almost all of these quakes happened within the most volatile part of the New Madrid Fault.

Let's not jump to conclusions or try to read too much into this. I've been fortunate to interview USGS scientists several time over the years and they helped me understand that small quakes like the ones in Missouri this week are to be expected. It could even be seen as good news as it shows the fault giving off non-damaging energy.

These small quakes only become an indication of bigger trouble to come if they are foreshocks according to the USGS. Here's how the USGS defines that:

Foreshocks are earthquakes that precede larger earthquakes in the same location. An earthquake cannot be identified as a foreshock until after a larger earthquake in the same area occurs.

Notice they emphasize that there's no way to say a swarm like this contains a "foreshock" unless it really is followed by a larger quake. So, when you see a collection or swarm of quakes like this mentioned, it does not necessarily mean it's a foreshadowing of something bigger to follow. But, it doesn't mean that something bigger won't follow either.