What is the New Madrid Seismic Zone and why are there earthquakes there?

Most earthquakes occur along the boundaries of the tectonic plates, which is why we have so many earthquakes in California, Oregon, and Washington. So why do we have earthquakes in the New Madrid seismic zone, which is in the middle of a plate? 

[ron]

I'm from New Madrid. I remember when Browning predicted an earthquake in 93. News crews everywhere, and I'm pretty sure the only person that got on tv was the only homeless guy in town. Rode his bike into town from the other side of the levee with tomatoes to sell. Where do you even get tomatoes in December?

[dennistate]

You are the outreach queen! Please consider 1) ETSZ and 2 ) potential impacts of NMSZ on areas like ETSZ both geophysically & response capacity impacts & best opps for improvements as you see it. Thank you!❤🎉

[hgbugalou]

What are your thoughts on some of the newer papers that hypothesize the source of stress on the realfoot rift comes from the mantle in the form of the remains of the Faralon plate sinking into the mantle at a sharp angle and pulling at the bottom of the lithosphere here? I tend to agree with this over the glacial rebound or accumulated internal stress from normal plate movement to the east. It also explains how so much energy was available to be released during the 1811-1812 cycle where most other intraplate Earthquakes are no where near this strong and with repeated, close events within a couple months. I wish the NMSZ got more study as I am of the opinion something geologically unique is happening here with the combination of a failed rift right on top of a mantle sink.

[gregmiller]

...the Reel Foot Rift....sounds like a dance...^^...i live in SE Missouri and we just felt a big tremor back a few months ago..i thought a jet had crashed on the hill, making my house shake and the rumbling sounded like an explosion of great force....it makes one feel quite humble ...

[thechronocal]

Man I live in the bootheel of Missouri lol, we gonna be SOL if it happens again

[dennistate]

"...when the continents were cuddling..." lol!

[DrilonUruqi]

Does this mean an East African-like rift is forming in North America?