Could A New Madrid Quake Shake Iowa’s Foundations?

Earthquakes aren't something we think a lot about here in the state of Iowa. We tend to be more worried about tornados and droughts. The 2020 derecho proved the kind of damage a severe storm can do. But perhaps we should also be paying a bit more attention to something that sits just to our southeast. The New Madrid fault line.

The New Madrid fault line is a major seismic zone that starts near New Madrid, Missouri and stretches to the southwest for nearly 150 miles. It is capable of producing large earthquakes that would affect a number of states here in the Midwest. The strongest earthquake ever produced by this fault line happened in 1811 and 1812. The New Madrid earthquakes started on December 16, 1811, with a magnitude 8.2 earthquake. A 7.4 magnitude aftershock hit the same day with two more earthquakes occurring in January and February of 1812. They remain the largest earthquakes to hit the U.S. east of the Rockies.

Could it happen again? Yes, but predicting when is nearly impossible. A report in 2008 warned that a major earthquake of 7.7 or higher at the New Madrid fault would produce "the highest economic losses due to a natural disaster in the United States." Would those of us living here in Iowa be safe?

According to estimates, it appears that we would see at least moderate damage from an earthquake at the New Madrid fault line. The good news is that we don't appear to be overdue for a large seismic event in the Midwest.

According to the Missouri Department of Natural Resources, the recurrence interval for large earthquakes is between 500 and 600 years. Since the last one at the New Madrid fault line happened in 1811, we wouldn't be 'due' for another big one until the year 2311. While it doesn't appear we're in any immediate danger, don't forget the sleeping giant that will come alive again someday.

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