New Madrid has had: (M1.5 or greater) 0 earthquakes in the past 24 hours 1 earthquake in the past 7 days; 8 earthquakes in the past 30 days; 193 earthquakes in the past 365 days Earthquakes in the New Madrid Fault Zone. The New Madrid fault appears to have a big rupture every 300 years or so; the Wabash Valley has one perhaps every 500 years.
An earthquake prompted by the New Madrid Seismic Fault Line occurs at 3 and 15 miles depth. The New Madrid seismic zone is located in the northern part of what has been called the Mississippi embayment.
And there is worse news yet, the fault line offers up extremely shallow earthquakes. The Mississippi embayment is a broad trough filled with marine sedimentary rocks about 50-100 millions years old and river sediments less than 5 millions years old. But when quakes do hit the central United States, geology means they are felt much farther away, because the Earth’s crust in the region does not absorb the shock waves in the way it does in the Western United States.
The New Madrid fault zone (NMFZ) is a long-established weakness in the Earth’s crust in the central and eastern US where earthquakes have occurred for hundreds of millions of years.
From Cairo, Illinois down through New Madrid, Missouri and then on into Arkansas. It also extends into parts of Tennessee. The New Madrid fault system was responsible for the 1811–12 New Madrid earthquakes, an intense intraplate earthquake series that began with an initial earthquake of moment magnitude 7.5–7.9 on December 16, 1811, and was followed by a moment magnitude 7.4 aftershock on the same day.