The Green Scene

Maybe you didn’t feel the earth move recently, but the animals did. On Dec. 18, seismologists recorded at least two small earthquakes in Western North Carolina and eastern Tennessee. Both quakes registered magnitudes less than 3, which means very little serious shakin’ went on (few humans even notice quakes below 2.5).

One Xpress forum contributor, however, saw a host of animals joining in an eerie chorus of chirps, howls and crowing that Thursday:

“I walked outside [at 1 p.m. on Dec. 18] and every bird in the forest was making as much noise as it could. I didn’t think too much about it until something that I think might have been a coyote started howling. Over the next few minutes, dogs and horses, squirrels and a rooster joined in, and a raccoon came out of the woods across the street and ran up the road. I decided to go inside before the larger nocturnal mammals showed up. It was rather eerie, and then it all just stopped at once. I thought we were going to have an earthquake. Now it’s 5:30 p.m., and the cacophony is starting up again.”

Another forum regular responded with detailed information from the U.S. Geological Survey’s earthquake Web site (http://earthquake.usgs.gov/eqcenter/recenteqsus). At 5:07 p.m. on Dec. 18, a 2.9-magnitude quake occurred approximately 4 miles south-southwest of New Market, Tenn., (and 20 miles east-northeast of Knoxville). That one registered at a depth of 6.3 miles. Judging by the site’s handy “Did you feel it?” summaries, residents reported very little shaking. Quakes of that magnitude and lower rarely cause damage, according to the Web site.

Less than two hours earlier, a microearthquake (magnitude less than 2) twittered monitoring devices in WNC—13 miles south-southwest of Hot Springs and 24 miles west-northwest of Asheville, at a depth of 4 miles.

Interestingly, nearly 200 small earthquakes were detected in the central and eastern U.S. in the last six months, according to Memphis State University’s Center for Earthquake Research and Information. At press time, no one from the department had returned calls seeking comment, but according to the CERI Web site, both east Tennessee and WNC are part of the New Madrid Seismic Zone—a series of faults extending 150 miles southward from Cairo, Ill., through New Madrid and Caruthersville, Mo. The zone is part of a “weak spot” in the continental crust called the Reelfoot Rift (named for Reelfoot Lake in Tennessee). The New Madrid system crosses a half-dozen states and intersects the Mississippi River in at least three places. It poses, CERI researchers say, “the greatest earthquake risk east of the Rocky Mountains.”

So what’s the possibility that an earthquake of magnitude 6 to 7 will occur along this fault system within the next 50 years? A whopping 90 percent, says CERI.

That’s something to ponder.

Consider that in the winter of 1811, several of the most powerful quakes in U.S. history (around magnitude 8) struck the Mississippi Valley. Centered in New Madrid, Mo., the temblors “caused cracks to open in the earth’s surface, the ground to roll in visible waves and large areas of land to sink or rise,” a summary on the USGS Web site notes. “The crew of the New Orleans (the first steamboat on the Mississippi, which was on her maiden voyage) reported mooring to an island only to awake in the morning and find that the island had disappeared below the waters of the Mississippi River. Damage was reported as far away as Charleston, South Carolina, and Washington, D.C.”

Maybe we ought to pay a little more attention when the animals all start going nuts.

For more information about earthquakes in our area, visit CERI’s Web site at www.ceri.memphis.edu.

Send your environmental news to mvwilliams@mountainx.com, or leave a message at 251-1333, ext. 152.