Early Tuesday morning a 4.0 magnitude Midwest earthquake struck near East Prairie, Missouri at 3:58am. Nine states from Indiana to Georgia felt the tremors which come after the 200th anniversary of the most famous earthquake from the New Madrid Seismic Zone. Recorded as the most powerful quake east of the Rocky Mountains, the Earthquake of 1812 affected the entire United States at the time, even causing the Mississippi River to reverse course. Back on February 7 of this year, many states, including Illinois for the first time, held their annual Great Central Shake Out Drill, preparing for the day of another major quake along the New Madrid Fault Line. The famous event actually was spread out over several weeks from December 1811 till February 1812 with the most intense on Feb. 7, estimated to be as high as an 8.6 magnitude quake by the U.S. Geological Survey. That would make it more than 10,000 times more powerful than yesterday′s earthquake.

New Madrid Seismic Zone

Earthquakes in the Eastern United States are not uncommon. You may recall the recent event in Virginia that caused some damage to the Washington Monument in Washington, DC. The main difference between earthquakes east of the Rocky Mountains and west is the affected area. There are more fault lines west of the Rockies, which tend to contain and limit the damage to a smaller area. Imagine striking one piece of a jigsaw puzzle. But with fewer fault lines east of the Rockies, even a modest earthquake might be felt over a very wide area, as if one struck a sheet of plywood.

Nearly half of all earthquakes in the United States each year occur in Alaska. Next comes the Pacific coast, from California to Washington State. The New Madrid Seismic Zone is the most active region east of the Rocky Mountains. About one hundred earthquakes occur annually, though usually only one per year is strong enough to be noticed, usually between a magnitude of 2.5 to 3.0. The East Prairie, Missouri Earthquake of 2012 came just two weeks after the annual Great Central Shake Out Drill, which many communities in the eastern United States use to prepare for another major event. Held on February 7, it commemorates the 1812 New Madrid quake which made the Mississippi River run backwards and was felt as far away as Boston, New York City and even Charleston, South Carolina.