Scientists: Origin of Madison quakes unknown

In less than two months, two earthquakes have hit Madison County and scientists don't know why.

Monday morning, a 3.2 earthquake hit 10 miles south southwest of Canton, according to the U.S. Geological Survey. The quake hit at 8:23 a.m. No aftershocks were reported, according to Paul Caruso, a geophysicist with the USGS.

No injuries or property damage has been reported, according to Heath Hall with the Madison County Sheriff's Department.

Caruso said the cause of the quake has not yet been determined.

"To determine why is going to take some time," Caruso said. "They're not going to know in 24 hours."

He added, "There's no way to know, especially if it's just been two earthquakes."

Another 3.2 quake occurred in Madison County on May 2. The quake hit four miles southwest of Canton. A 3.0 aftershock occurred shortly after.

Michael Bograd, state geologist with the Mississippi Department of Environmental Equality, said earthquakes have been recorded in Mississippi for the last 300 years. However, he said, earthquakes in central Mississippi are rare.

Bograd said while he and his colleagues are aware of fault lines, many Mississippi scientists do not have access to a seismograph to measure an earthquake's seismic waves. Without one, tracking the quake's origin is no small feat.

"There have been faults mapped in the subsurface, deeply buried, and a lot of faults have been mapped," Bograd said. "How to tie any earthquake to a particular fault is very problematic."

The distance between the quake a seismograph can also dilute results.

"The farther away the less precise the calculation of depth," he said

Dr. Bob Herrmann, professor of geophysics at St. Louis University Earthquake Center, said Monday's quake was "a strange one."

"Small earthquakes can pop off randomly," he said. "Unfortunately, this is a rarity and we don't really know why."

Herrmann said scientists can't predict when or where a quake will occur.

Bograd said there is no way to know if the recent earthquakes are the beginning of a trend but said his office is trying to learn all they can from the acts of nature in the meantime.

"Today's earthquake could have been just the third in the series or the last one," he said. "There's no way to even speculate if there will be more following these three. Science can't predict earthquakes. We're just trying to observe what is happening and learn what we can through these events."

Bograd said while there is CO2 drilling occurring in southwest Mississippi, the waste water injection wells are not the cause of the recent quakes.

"Oil and gas activities are not related to this event," Bograd said. "As far as I know, there is no connection. Something miles and miles away in southwestern Mississippi could not conceivably have had an effect this far away."

Contact Sarah Fowler at sfowler@gannett.com or (601) 961-7303. Follow @FowlerSarah on Twitter.