Earthquakes cause small stir in Lake County

Two small earthquakes rumbled in Lake County, Tenn., on Friday and Saturday, Jan. 13-14.

The Friday quake, registering a magnitude of 1.2, occurred at 6:46 a.m. and was located 5 miles south-southeast of Ridgely, Tenn., and 11 miles north-northwest of Dyersburg. The depth of the quake was 4.1 miles.

Saturday's quake hit at 5:45 p.m. and had a magnitude of 1.5. Its depth was 4 miles and its epicenter was 2 miles south-southwest of Tiptonville, 6 miles north of Ridgely and 8 miles west-southwest of Samburg.

Lake County is part of the New Madrid seismic zone, which includes portions of five states and is the most active seismic zone in North America east of the Rocky Mountains, according to the U.S. Geological Survey (USGS) Earthquake Hazards Program. Areas in the zone are West Tennessee, western Kentucky, southeastern Missouri, extreme southern Illinois and northeastern Arkansas.

Two hundred years ago, during the winter of 1811-1812, the region was rocked by three devastating quakes, all with a magnitude of 7.0 or larger.

The quakes occurred on Dec. 16, 1811; Jan. 23, 1812; and Feb. 7, 1812; they were among the largest to strike North America since European settlement and were felt throughout much of the nation, according to the USGS.

That series of quakes formed Reelfoot Lake in northwest Tennessee near Tiptonville.

The USGS web site also showed that hundreds of aftershocks, some of which also caused severe damage, followed the massive 1811-12 earthquakes for years.

And, since 1900, "moderately damaging earthquakes have struck the seismic zone every few decades," according to the USGS.

On Feb. 7, the anniversary of the third major quake in the 1811-12 series, more than 1 million people across nine states will participate in the Great Central U.S. ShakeOut, scheduled for 10:15 a.m. CST.

During the event, people in schools and in other groups will practice the quake safety technique of "drop, cover and hold on."

Local participants in the ShakeOut include the Weakley and Obion county school systems, the Dyersburg school system and the Bradford Special School District.

Three days later, on Feb. 10, the Weakley County Emergency Management Agency is staging one of the biggest disaster drills to be held in Tennessee.

Much of the drill will occur in Martin, and in keeping with the quake anniversary, the drill is centered on an earthquake disaster.

For more information on quakes, visit the USGS web site at www.usgs.gov. The site also includes tips for earthquake preparedness, a continuously updated list of recent quakes, and a link to sign up for a Twitter feed to find out about nearby seismic activity.