Up until late last month, the earthquake threat for North Alabama seemed relatively small.

However, two Tennessee Valley towns — Elkmont and New Market — experienced minor earthquakes within just five days of each other, though neither measured above 2.5 and no damage was reported.

“There is some sporadic (activity) around that part of the state, but mostly toward the mountains in the northeast,” said John Bellini, a geophysicist with the U.S. Geological Survey’s National Earthquake Center. “It’s normally a very low activity area; it’s not a seismically active state.”

Despite a seemingly small earthquake threat, the Alabama Emergency Management Agency is encouraging residents, schools and businesses to take part in The Great Central U.S. Shake Out preparedness drill, to be held Thursday.

The exercise, organized by the Central United States Earthquake Consortium, and featuring participation from Alabama, Arkansas, Georgia, Kentucky, Illinois, Indiana, Mississippi, Missouri, Oklahoma, South Carolina and Tennessee, will start at 10:15 a.m. The overall purpose of the drill is to have participants simultaneously practice the recommended action during an earthquake — drop to the ground, take cover and hold on until the shaking stops.

According to a press release from the Alabama EMA, scientists estimate a 25 to 40 percent probability of a damaging earthquake occurring in the central U.S. within the next 50 years.

Art Faulkner, director of the Alabama Emergency Management Agency, said the drill has two primary goals — to put the danger of earthquakes on the radar screen of Alabamians and ensure residents know what to do in case of an earthquake.

“We prepare for hurricanes, tornadoes and things of that nature, but we want them to be just as prepared for earthquakes,” he said. “Unlike the severe weather that moved through the state last Friday and Saturday, there is no advanced warning for an earthquake, so it makes it that much more important that you know what you’re going to do.”

More than 1 million people are expected to take part in the Shake Out, though only two Limestone County residents had registered as of Thursday. And despite having a locally recorded earthquake, no schools or businesses in Athens or Limestone County had registered to participate, even though six schools in Madison County and one in Morgan County had registered.

Given the close proximity of Browns Ferry Nuclear Plant and the recent recorded earthquakes, Faulkner said “some areas of the state should be more aware” of the drill than others.

“If nothing else, this drill is going to show us where we may need to focus more concentration of preparedness efforts and public information to first responders,” he said.

Daphne Ellison with the Limestone County EMA said the information had been sent to local schools, but schools leaders may not have known they had to register to participate. She said the local EMA would be participating in the drill, though she didn’t have specifics on activities.

“At this point in our plan, we may pretend that we’re going to send out a press release to let everyone know what happened,” she said. “We’ll just practice what we would do in that situation.”

For more information on the Great Central U.S. Shake Out, visit www.shakeout.org.