Small Earthquakes Shake Virginia Over the Weekend

Two mild earthquakes registered in Virginia over the weekend, about 12 miles southeast of Louisa, Va., the same area that was the epicenter of the "big" earthquake that struck five years ago, according to the U.S. Geological Survey. The first of this weekend's small quakes in Louisa, located between Richmond and Charlottesville, registered late Saturday at 11:34 p.m. at 1.6 magnitude; the other one shook the ground about an hour later, registering at 1.9 magnitude.

The small quakes rattled near the epicenter of the rare "big" quake that struck the entire region five years ago, Aug. 23, 2011. That quake, also centered at about 12 miles southeast of Louisa, registered 5.8 magnitude and was reported as far north as Canada. The U.S. Geological Survey (USGS) estimated that one-third of the U.S. population felt the quake that day. One year after the quake, more than 450 aftershocks were recorded, the USGS said.

Some speculated the big earthquake was a result of fracking natural gas production. Geologist James Coleman, who works for the U.S. Geological Survey, told NPR that while fracking can cause earthquakes, it didn't create the 2011 quake in Virginia.

“It’s pretty clear that in some areas, underground injection of wastewater causes relatively small earthquakes, smaller than what we had here in Virginia, but disturbing to some people,” Coleman said.

A spokeswoman for the USGS said Monday that the government has a team of earthquake experts who have been working in the Louisa area since the quake in 2011.

PHOTO: Map shows location of 1.9 and 1.6 earthquakes this weekend in Virginia, about 12 miles southeast of Louisa; U.S. Geological Survey map