The Vagabond: The Gadsden Fault - an earthquake waiting to hit Gadsden?

October 12, 2018 chris
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By Danny Crownover

This week, The Vagabond will discuss the Gadsden Fault, which follows part of the High Town Path around Gadsden.

Over the years, The Vagabond often has admired the local stone formations that tell an exciting geological story. There are strange examples of wind and water erosion that have been carved during the past twenty million years. Geologists say that an ocean covered the area until some 200 million years ago, when the Appalachian Mountains were born after a tremendous upheaval.

Eventually, wind and rain began beating this mountain, and almost succeeded. Twenty million years ago, the rise of the Cumberlands caused the present Lookout Mountain to be uplifted and formed.

When the mountain rose, a syncline creating Black Creek was formed. The syncline is “U” shaped with the creek on the bottom and an eastern and western ridge on the east and west sides on Lookout Mountain. 

At the very southern terminus of the mountain is the east-west fault known as the “Gadsden Fault.” The fault is located north and parallel to the present Tuscaloosa Avenue and runs from Attalla to Ewing Avenue near the Coosa River. For the most part, the High Town Path follows the fault.

Geologists have stated that the displacement along this fault may be as much as 7,000 feet or more. Translated, that means Lookout Mountain was once higher than the Rockies and the Alps. It also means that the birth of Noccalula Falls was located about a mile down the gorge, about where the Etowah County Rescue Squad building is now located. And get this –  Noccalula Falls was once several thousand feet high!

However, this uprising was 20 million years ago. Today, the fault is not as active as California’s San Andreas Fault. But don’t think it is impossible for the local fault line to ever slip again.

Just a couple hundred years ago, a catastrophic earthquake unheard of today hit along a fault line near Paducah, Kent. It changed hundreds of miles of landscape forever and created a huge lake. Most folks living in that area today do not realize the immediate and dramatic land change that took place in a matter of seconds. That time period is considered “recent” on the geologic time scale.

Believe it or not, we still have tremors and earthquakes in this area. The Vagabond remembers an earthquake several years ago hitting the Etowah County area strong enough to rattle folks awake. There also was a recent earthquake at a fault line under Lookout Mountain in the Mentone/Cloudland, Ga., area that many will recall.

The largest earthquake recorded in Alabama occurred on Oct. 18, 1916. A magnitude 5.10 earthquake occurred around 4 p.m. in an unnamed fault south of Gadsden, with the epicenter located near Easonville in St. Clair County. The earthquake caused buildings to sway in downtown Birmingham and tied up all phone lines in the city, with 25,000 calls recorded at the main exchange in the hour following the quake.

Two additional weaker tremors were reported that evening. In Irondale, 14 chimneys in a two-block area were partly destroyed and six chimneys on a brick store were leveled almost to the roof. Many other chimneys either were leveled to the roofs or cracked so badly that they had to be rebuilt. There also were reports in the quake area of windows broken and frame buildings “badly sha-ken.” The earthquake was noted by residents in seven states and covered 100,000 square miles.

In 1946, drillings made by the U.S. Bureau of Mines in Owls Hollow brought out a vertical cross section of the different formations found under southern Lookout Mountain and Noccalula Falls. It was found that rocks were deposited in five major geological periods – the Carboniferous, Devonian, Silurian, Ordovician and Cambrian eras. Many significant fossils have been found from the Cambrian Period, dating back 570,000,000 years ago.

For those who wish to view these layers up close, observation of the Interstate 59 cut through the mountain approximately three miles north of the Noccalula Falls exit shows a superb picture of these different strata as they slope downward toward the center of Lookout Mountain. The cut through Shinbone Ridge in Owls Hollow is a good start.

If one will look at the route the High Town Path takes, he or she will notice that the route never crosses Lookout Mountain. Rather, the trail avoids the mountain by taking the southern route around it, which crosses directly over the Gadsden Fault.

So the next time you start to go up Noccalula Road or travel around the Tuscaloosa Avenue area, be sure to hold on – there could someday very well be an earthquake to hit!