Tennessee Valley – The Time Bomb?

7 04 2009

You watch it all the time at the movies. Perhaps, you watch it on the news too. You hear about the disasters and the after-effects of them. They are earthquakes. If you are reading this blog and you are a resident of the Southeastern United States, then you are definately in the right region for a risk of a major quake. Given, we haven’t had a major earthquake in the Southeastern United States since 1812. Back then, they did not record the intensities of earthquakes on what is now the Richter Scale – instead, geologists take into account the damage that was left behind, the changes in the topography of the land, eye-witness accounts and other like factors. They estimated that the quake would have been classified as a “Mega-Quake” with an intensity of over 8.0.

Image displays the location of the New Madrid Fault Line.

The effects of the quake were so intense that the massive Mississippi River completely shifted course and Lakes (such as Lake Reelfoot, TN) were formed from massive sinkholes. Citizens several hundred miles from the massive quake’s epicenter felt the vibrations of the disaster, as far away as Illinois, Missouri, Alabama, Tennessee, Georgia, Mississippi, Arkansas, Texas, Louisiana, Kentucky and Indiana. The intensity was so startling, that church bells in Boston, MA rang with the shockwaves from the massive quake. So is the quake a “once-in-a-lifetime” event? Perhaps. The average lifetime is 72 years and it happened 197 years ago – so we could be due for another giant quake.

Image displays both earthquakes of 1995 in CA and in 1895 in Missouri along the New Madrid Fault – the colors displayed are the damage spreads of each.

Not only do we have to worry about the New Madrid Fault – we also have, in our area, the Appalacian Fault and the Bermuda Fault. Areas in Northern Alabama (Huntsville, Anniston, Cullman, Florence, Athens, Scottsboro, Decatur) are particularly in the danger zone of the Appalacian Fault stretching southwest from the feet of the Appalacian Mountains. Although no “Massive” quakes have been recorded from the zone, hunderds of smaller quakes have happened. Usually 3-4 times a year, the zone in the northeastern 75 miles of the state recieve a weak earthquake, usually in the 2.0 – 3.5 range on the Richter Scale. This is not a large number, barely noticable to most and usually only causes minimal damage to perhaps windows, loose or unstable chimneys to name a couple. Just because a significant earthquake has not happened in northeast Alabama from the Appalacian Fault does not mean that it can’t — or won’t.

Image displays the number of confirmed earthquakes in the New Madrid Region only since 1974.

Slightly more prone to a larger quake are those persons whom dwell and reside in the southern extent of Alabama (Dothan, Greenville, Montgomery, Selma, Mobile) from a large grouping of fault lines known as the Bermuda Fault Zone. The area stretches from slightly south of Birmingham, AL southward into the Florida Panhandle. Several quakes are recorded each year – ranging from 2.0 all the way up to 4.5 (as in the case of the earthquake just to the east of Birmingham not too long ago).

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Image displays the spread of damage extending far from the epicenter.

Although the worst case scenario would likely be a quake much like the one of 1812, quakes of that intensity are rare and infrequent. Residents of the Tennessee Valley shouldn’t move out of the southeast just because of the earthquake “potential”, you’ll find that anywhere. Remember, if you get woke up at night because your house is vibrating, it’s likely just a small and common quake (or your spouse is REALLY putting too much time into mechanical engineering). I hope you have enjoyed this article and if you like it, please pass it on and comment on it. I would greatly appreciate it.

Derrick Wales