The U.S. Geological Survey reports a 2.0 magnitude earthquake struck Friday morning near Cleburne, the latest in a series of low-intensity tremors in that area.

Friday's quake was registered at 6:58 a.m. and was centered four miles east of Cleburne. At least six other earthquakes have been recorded since June 2 in the city about 30 miles south of Fort Worth.

Geological researchers from Southern Methodist University are working with city officials to determine whether citywide gas drilling, which began about six years ago, is causing the quakes.

The quakes, unusual for this part of Texas, have originated about three miles beneath the ground, while most of the drilling occurs about a mile deep.

The Dallas Morning News contributed to this report.