Mystery: Alabama earthquake swarm stuns residents and geologists alike

June 2015– ALABAMA – Early one morning last November, Jim Sterling was frightened when the ground began shaking outside his 156-year-old antebellum home in Alabama. He grabbed his gun and ran outdoors, where he found horses galloping, cows mooing and dogs barking. It was an earthquake. “I heard a boom and felt the shaking,” Sterling said. “It really upset me.” Since that day, more than a dozen weak earthquakes have shaken western Alabama’s Greene County. Geologists are now working to find out what has caused this swarm over the last seven months, in an area of the South that’s used to large tornadoes but not light tremors. “It is interesting that recently there has been more activity there than in the last four decades,” said Sandy Ebersole, an earthquake expert with the Geological Survey of Alabama.

Records from the U.S. Geological Survey show the first of 14 earthquakes occurred…