As concerns mount in several states that fracking may be linked to earthquakes, UNC-Chapel Hill geologists plan to conduct seismic tests in Lee and Chatham counties to document naturally occurring earth movements in the region.
The geologists are looking for a dozen property owners to donate about 100 square feet of land to host a seismo meter for at least a year, during which the area would be fenced off and inaccessible.
With the state legislature likely to debate legalizing natural gas drilling this summer, university and government scientists are quickly lining up private land owners as participants in scientific research on the region's natural resources. In addition to seismology measures, scientists will also measure water quality in about 75 local wells.
UNC geologist Lara Wagner said about 15 property owners to date have expressed interest in participating in the seismology tests, but the properties must be assessed for suitability. Some could be too close together, while others could be in areas that are too shady to accommodate the solar panel needed to power the seismometer.
Fracking, or hydraulic fracturing, is a technique used in conjunction with horizontal drilling to access natural gas trapped in prehistoric shale formations. Fracking involves pumping several million gallons of water, sand and chemicals at extremely high pressure to fracture the rock and release the gas.
Geologists estimate North Carolina could hold a 40-year supply of natural gas in shale rock beneath Lee, Chatham, Moore, Durham and other counties. Some state legislators are eager to tap the clean-burning domestic energy resource to offset burning dirty coal and importing foreign oil.
In states where the drilling and fracking are legal, residents have complained of water contamination and other ills. Several states have experienced ground tremors, including Ohio, where 11 quakes were recorded last year, culminating with a 4.0 magnitude jolt on New Year's Eve.
It's not clear what causes the quakes, but one possible cause is the injection of briny wastewater that can act as a lubricant to loosen underground faults, causing them to slip.
Wagner, the UNC-CH geologist, said fracking could also be a contributor.
"You're breaking up rock, and that additional weakness is allowing things to fail that were close to failing before," she said.
Industry representatives say the link is not proven and that the drilling technology is safe.
The outdoor study here would be modeled on more than 100 similar sites in Georgia and in South America, where university scientists are tracking earth movements over an extended period. Those studies are not related to fracking.
The seismology testing uses ultra-sensitive seismic detection units buried in a plastic tub. The seismometer takes 40 readings per second.
The optimum site will be away from railroad tracks, major roads and trees, whose roots can distort ground movements, Wagner said.
"If you walk past them, your dog walks past them, a truck rolls down the road, we'll pick that up," Wagner said.