According to various earthquake experts the largest earthquake ever recorded was the 1811-1812 New Madrid quake. This one quote I found:
In December of 1811, a the largest earthquake ever recorded in American History started. This earthquake, called the New Madrid Earthquake because of its primary location on the New Madrid Fault, near New Madrid, Missouri. From the effects of the 1811-1812 earthquakes, it can be estimated that they had a magnitude of 8.0 or higher on the not yet invented Richter scale. Large areas sank into the earth, new lakes were formed (Reelfoot Lake), and the Mississippi River changed its course due to the earthquakes. (Some say it appeared to flow backwards-as it filled the void.) There were a series of 5 quakes. This would make a total of five earthquakes of magnitude MSn 8.0 or higher occurring in the period December 16, 1811 through February 7, 1812.
As if that was not bad enough, quote:
Some scientists claim that the so-called “Big One” will not happen on the West Coast at all. Rather, a surprising number of them argue that the next sizable shake might occur along the New Madrid Fault, probably by the year 2010. Other authorities, like The Central United States Earthquake Consortium, say there is a 90 percent chance of a magnitude six or seven earthquake hitting the Mississippi Valley within the next 50 years. The National Earthquake Center of the U.S. Geological Survey (USGS) is more general in its prediction. It suggests that the possibility of such an earthquake “might occur as soon as next year or as late as several thousand years hence.” But all have come to the same conclusion. Disaster will strike the Mississippi again.
Gee Thanks for the good news!!!!!!!!!!!!!
Jeff