A SMALL EARTHQUAKE TOOK PLACE in western Tennessee Friday that registered 2.8 on the Richter scale, not enough to do any damage. But the folks who live in the area over the New Madrid Fault are used to it, even though most people in other parts of the U. S. are not aware of this geological fault.
The New Madrid (mad’-rid) Fault is the most active earthquake zone outside of California and is found in the area that roughly follows Interstate Hwy. 55 from Charleston, Missouri, through New Madrid and Caruthersville, then on to Blytheville, Arkansas.

The New Madrid seismic zone
While damaging tremors are not as frequent as in California, when they occur, the destruction covers over more than 20 times the area because of underlying geology. The fault averages more than 200 measured events per year (1.0 or more on the Richter scale), about 20 per month. Tremors large enough to be felt (2.5 – 3.0 on the Richter scale) are noted annually. Every 18 months the fault releases a shock of 4.0 or more, capable of local minor damage. The most recent registering 4.3 along the New Madrid Fault on Thanksgiving evening, 1996, which was felt by citizens in the states of Missouri, Arkansas, Tennessee and Kentucky, Illinois and Mississippi. Magnitudes of 5.0 or greater occurring about once per decade, can do significant damage, and be felt in several states.
A “damaging” earthquake (6.0 or greater) occurs about every 80 years (the last one in 1895). The results would cause serious damage to schools and masonry buildings from Memphis to St Louis. A “major” category quake of 7.5 or greater happens every 200- 300 years (the last one in 1812). There is a 25% chance for one of those to occur by 2040. A New Madrid Fault rupture this size would be felt throughout half the United States and damage 20 states or more. Most likely though, there is a 90% chance for a 6.0 quake by 2040.
Truly, that last major quake that occurred in 1812 was the worst in North America in recorded history. Several times larger than the San Francisco earthquake of 1906, it was actually a series of 2,000 quakes over a 5-month period with ten of them registering 8.0 or higher. Eighteen of them were felt throughout the entire eastern half of the U. S. and literally rang church bells as far away as Boston. The Mississippi River ran backwards, frighening the daylights out of steamboat passengers, and geysers sprouted sending jets 80 feet in the air. Some buildings were damaged in Charleston, South Carolina, and Washington, D. C.
The heaviest tremor took place on February 7, completely destroying the town of New Madrid and draining several lakes, as well as altering the course of the Mississippi River in several locations resulting in some settlements ending up in a different state entirely.
Friday’s tremor is being taken seriously by seismologists because it follows five similar quakes two months ago in Arkansas which is an area where seismic activity is practically nil.
Just one more thing for fire and rescue planners in the mid-west to worry about.
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