Posted by Michael Heitman
on April 29, 2003

The magnitude 4.9 earthquake ocurred at 3:59 a.m. in northeast Alabama.

A light earthquake centered in Northeast Alabama woke up local residents throughout the region early Tuesday morning. The magnitude 4.9 earthquake ocurred at 3:59 a.m. (Central Time) and was centered 4 miles SSE of Valley Head, Alabama or about 42 miles SSW of Chattanooga. There have been no reports of damage or injuries, but the earthquake was felt as far away as Fort Wayne, Indiana. Tennessee Emergency Management Agency officials recieved numerous calls and notified Governor Bredeson of the earthquake.

Many residents woke up because of the shaking and wondered exactly what was going on. Randolpho St. John of Cookeville, gave his account of the early morning event, "At around 4 this morning, I was awakened by my house shuddering, as if in a strong thunderstorm or windstorm. In fact, that's what I thought it was, at first. My second thought was 'Oh my God, I left the windows down on the car!' So I jumped up and ran to the window to see if I left the windows down. It was then that I noticed that not only was it not raining, but it wasn't windy either. 'Must be an earthquake,' I thought, and went back to bed."

Earthquakes are pretty rare in this region of the country. However, in northwest Tennessee along the Mississippi river there is frequent activity along the New Madrid fault. This fault is most notable for the eartquakes that hit the region back in 1811-12 which caused many areas to sink and rise which included the formation of Reelfoot Lake. There are also earthquakes in eastern Tennessee near the North Carlonia border. One earthquake in 1973 near Knoxville caused some damage which includes cracks in the University of Tennessee hospital building.

Dr. Hugh H. Mills, Professor of Earth Sciences at Tennessee Tech University, who has performed basic research concerning earthquakes in this area, says that no place in the nation is completely safe from the possibility of having a significant tremor.

"The New Madrid fault running through West Tennessee is the most active earthquake area in the eastern United States, but an area doesn't necessarily have to be on or near a major fault line for an earthquake to happen," he said.

When a significant earthquake does happen in such an area, though, it generally originates from deep within the earth, and it is therefore more difficult to determine its actual cause.

Tuesday morning's quake was a 4.9 on the Richter Scale, he said, and it was strong enough to knock mobile homes from their foundations near the epicenter. One that ranks at six or higher on the scale could cause serious structural damage.

"But the higher on the scale you go, the more rare it is for such a serious earthquake to happen," Mills said. "The likelihood of having an earthquake like that in this area is probably once in a hundred years."

The Official U.S.G.S., National Earthquake Center Report

== PRELIMINARY EARTHQUAKE REPORT == U.S. Geological Survey, National Earthquake Information Center

Version #7: This report supersedes any earlier reports of this event. This event has been reviewed by a seismologist.

A light earthquake occurred at 8:59:37 (UTC) - Coordinated Universal Time on Tuesday, April 29, 2003. The magnitude 4.9 event occurred 7 km (4 miles) SSE of Valley Head, AL. The hypocentral depth was 5 km ( 3 miles).

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Magnitude 4.9 - "Nuttli" surface wave magnitude (MbLg)
Time Tuesday, April 29, 2003 at 8:59:37 (UTC) - Coordinated Universal Time
Tuesday, April 29, 2003 at 5:59:37 AM (ADT) - Atlantic
Tuesday, April 29, 2003 at 4:59:37 AM (EDT) - Eastern
Tuesday, April 29, 2003 at 3:59:37 AM (CDT) - Central
Tuesday, April 29, 2003 at 2:59:37 AM (MDT) - Mountain
Tuesday, April 29, 2003 at 1:59:37 AM (PDT) - Pacific
Tuesday, April 29, 2003 at 12:59:37 AM (AKDT) - Alaska
Monday, April 28, 2003 at 10:59:37 PM (HST) - Hawaii
Distance from Valley Head, AL - 7 km (4 miles) SSE (168 degrees)
Mentone, AL - 7 km (5 miles) SSW (195 degrees) Hammondville, AL - 8 km (5 miles) SSE (154 degrees) Rome, GA - 47 km (29 miles) NW (306 degrees) Chattanooga, TN - 67 km (42 miles) SSW (207 degrees)

Coordinates 34 deg. 30.5 min. N (34.508N) 85 deg. 36.1 min. W ( 85.602W)
Depth 5 km (3.1 miles)
Location Uncertainty horizontal +/- 7.7 km (4.8 miles); depth fixed by location program
Location Quality Parameters Nst= 25, Nph= 25, Dmin=84.2 km, Rmss=0.98 sec, Erho=7.7 km, Erzz=0 km, Gp=97.2 degrees
Event ID# usteak