Concerns over natural gas development and its potential to cause earthquakes continue to linger in Johnson County, TX, after the area has experienced about 10 modest quakes during the last month.

The last quake was Friday and measured 2.7 on the Richter Scale. There were no reports of damage or injuries. Residents of the area have become used to the occasional trembling.

“We talked about it at the coffee shop this morning, but nobody felt it,” Johnson County Judge Roger Harmon told the Fort Worth Star-Telegram. “I think they’ve become so prevalent that everyone is like, ‘Well there goes another one.'”

As in other parts of the country where minor quakes seem to have accompanied an uptick in shale gas development, some residents in North Texas wonder if injection wells used to dispose of drilling waste are the cause of the earthquakes.

Earlier this year the Railroad Commission of Texas said two earthquakes that recently shook the area around the East Texas town of Timpson were unlikely to have been caused by natural gas drilling or drilling waste disposal activities (see Shale Daily, May 22).

However, researchers at the U.S. Geological Survey (USGS) cited drilling-related injection wells as the reason for a “remarkable” uptick in seismic activity (see Shale Daily, April 2). Scientists from the USGS earthquake research center in Menlo Park, CA, said there has been a six-fold increase in the number of earthquakes of 3.0 magnitude or greater since 2001, over 20th century levels. However, state geologists in Colorado and Oklahoma disputed this finding, at least in its application to the Midcontinent (see Shale Daily, April 17).

In March the Ohio Department of Natural Resources (ODNR) said a dozen small earthquakes in northeastern Ohio over the last year may have been triggered by a wastewater disposal well in Youngstown (see Shale Daily, March 12). Last week, Gov. John Kasich issued an executive order calling for tougher regulation of injection wells (see Shale Daily, July 13).

Last year regulators in Arkansas established a moratorium on wastewater disposal wells in an area of the Fayetteville Shale after similar quake activity was reported there (see Shale Daily, July 29, 2011; March 4, 2011).