ST. LOUIS, Mo. – What are the chances of an earthquake occurring near St. Louis? There is an active area nearby called the New Madrid Seismic Zone. It is the most active zone east of the Rockies, with a dark history.
There was a series of quakes from 1811-1812 with magnitudes of 7.5 on the Richter scale. They were triggered by a fault line in Missouri’s bootheel.
When the tectonic plates in the earth shift they cause energy to be released underground. That sends vibrations, shaking the earth.
Earthquakes are measured in terms of magnitude from the energy released on a 1-10 scale. Anything over six shakes local buildings with damage possible. Anything over seven is considered a real whopper with lots of damage and can be felt for hundreds of miles.
“We know that the fact it’s active. The big ones are going to be coming one of these days,” said Missouri Earthquake Program Manager Jeff Briggs. “We don’t know if it’s going to be tomorrow or 100 years from now, but we know that the risk is there.”
The 21st century could see much more of an impact from a large earthquake.
“Unlike 200 years ago there are now millions of people living in this vicinity,” said Briggs. “If a big one happens now like what happened in 1811 and 1812, the shaking and damage are going to be felt completely across the region. There are going to be likely millions of people without power, without water for days or even weeks.”
There is a 25 to 40 percent chance of a magnitude six or greater earthquake from the New Madrid Zone in the next 50 years. The chances for a magnitude seven or greater is between 7-10 percent.
The Missouri National Guard routinely runs drills and is trying to inform the public.
“If you can take steps now to minimize the chance of things falling on you that’s really the most important thing you can do to prepare yourself,” said Briggs.