The Earthquakes of 1811 and 1812 in the Mississippi River Valley

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When one thinks of earthquakes, the Mississippi river valley (MRV), does not

frequently come to mind. One usually thinks of one of California's numerous faults or

somewhere in Alaska. However, little known to the general public, there were two

massive earthquakes in the MRV, which rank among the top three in the contiguous

United States and in the top ten for the entire United States (http://wwwneic. Starting in the early morning hours of December 16,

1811 a violent shaking of the earth began, which continued on for three months,

producing two of the three largest quakes in the contiguous US, this particular quake

registered an 8.0 in magnitude on the Richter scale. There was a second quake on

February 7, 1812 which registered 8.2 (


The plate which is responsible for this activity is named the New Madrid Seismic

zone, it is named for the only populated city that was in existence in the time and the area

of these earthquakes, New Madrid, Missouri.

The New Madrid Seismic zone lies in the

central MRV, starting in southern Illinois and ending in southeast Missouri, western


Usually an earthquake consists of a principal shock and then the aftershocks, the

1811-1812 earthquakes didn't follow the usual pattern. There was the first primary shock,

at and then it's aftershocks, however the aftershocks from the first quake hadn't subsided

before the second principal shock hit. Following suite, the aftershocks from the second

quake had not terminated when the third and largest principal shock hit (http://www.eas. It is difficult to gage the actual

intensity of the earthquakes due to the lack of technology, however, the strength can be

estimated by the damage caused by the quakes and also by the journals of the people

settling this part of the country. Fortunately, a...