Although Mississippi residents are unaccustomed to earthquakes, such as the 3.2 magnitude earthquake that shook Madison County the morning of June 29, the state is no stranger to earthquakes, said Charles Swann, associate director for state programs at the Mississippi Mineral Resources Institute.
Swann’s research on earthquakes at the MMRI shows that the state has a number of epicenters running throughout it.
“There [are] quite a few earthquakes that have occurred throughout the state,” Swann said. “People don’t often associate Mississippi with earthquakes, but if you go back and record all the earthquakes [in which] we can find epicenters, they plot all over the state. There have even been earthquakes on the (Gulf) Coast.”
Swann noted while many may question if the earthquakes from June 29 and at least one other earthquake on May 2 were oil and gas related, he does not think so.
“There are no oil wells or injection wells near the epicenter of this earthquake. So probably it has nothing to do with it. It’s just a fault that’s moving,” Swann said.
Swann also said Mississippians feel earthquakes differently from residents of California, where earthquakes happen more frequently. This phenomenon happens because the plate structure and geological makeup of the central U.S. differs from that of the West Coast.
“This sort of geology is interesting because it transmits seismic waves very well,” he said. “So an earthquake of, let’s say, a magnitude 5 in California will be felt over a certain area. You take that same earthquake and move it to the central United States, and you have a 5 here, and it may be felt over that particular area times two or times three because of the geology.”
The Madison County earthquake epicenter is located on a fault that could be a southernmost part of the New Madrid fault. Swann said little research has been done on that particular area.