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.
cr.usgs.gov/neis/eqlists/bigten.lis). 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 (http://wwwneic.cr.usgs.gov/neis/eqlists/
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.
slu.edu/Earthquake_Center/Nuttli.1973/intensity.html). 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...