Why are scientists nervous about a Memphis earthquake?

Hundreds of earthquakes happen every day, but often we assume they aren’t hitting home in the Mid-South.

That assumption isn’t entirely accurate. In fact, the potential for major devastation is right here in our backyard.

On Saturday, October 16, a 3.6 magnitude earthquake shook our area. The quake’s epicenter was Manilla, Arkansas.

That’s along the New Madrid Fault line, which you may have heard about. What you likely don’t know is the correct terminology is the New Madrid Seismic Zone.

The zone is a series of faults and secondary fractures that extend from Marked Tree, Arkansas into southern Illinois. One of the elements that makes the system unique is that, unlike most fault lines, it has a beginning in an end.

That fact alone has a team of more than 50 scientists from across the globe stationed in Memphis. Gary Patterson leads the team that’s studying the dangerous situation.

"Memphis is in a very unique location, and I'm not talking about 20 to 40 feet down,” Patterson told FOX13’s Joey Sulipeck. “I'm talking about miles in depth underneath Memphis. You'd have to go down over half a mile before you got to bedrock."

The soil we live on makes it even more dangerous.

Bedrock absorbs the vibrations of an earthquake differently than soft sediment, which is what Memphis and the surrounding region is built upon.

We asked Gary Patterson to simply the problem.

“This area is basically on a deep dish of sediments that shake like Jello,” he said.

The danger is a combination of several things. Among them are:

  • A unique fault zone with a constant threat of surprise energy release
  • A soil system surrounding the Mississippi River that is soft sediment-based

There is another key problem to the equation that relates to many people in the Mid-South. Our area has a large population of older home; ones that are not built to survive a strong earthquake.

"It really is a different kind of quake here. You take the same magnitude event and you put one in California and one here, the one here will be felt over a ten times larger area,” Patterson explained.

Events like last week’s Great American Shakeout are designed to help us prepare for a major quake.

However, the frightening truth is so much of the science is still not understood.

“We're an enigma. It's a puzzle and many scientists have dedicated their whole careers trying to figure this out,” Patterson told FOX13.

So that leaves a major question: When will the big one hit?

Gary Patterson helped FOX13 crunch those numbers. Best estimates indicate that over the next 50 years, the probability of a magnitude 6 or larger quake is between 25 to 40 percent.

In short, if you are 35 years old or younger, there is a good chance you will experience an earthquake in the Mid-South that measures higher than a 6.