CLEBURNE, Texas -- The ground shook, windows rattled and the North Texas town of Cleburne was dealt its sixth earthquake in less than a month.
The U.S. Geological Survey says the 10:30 p.m. Friday tremor registered a 2.2-magnitude and was centered about four miles east of the city.
Two other small tremors were felt in May, and three others hit the area in early June, according to the U.S. Geological Survey.
Cleburne officials are working with researchers from Southern Methodist University to determine if nearby gas drilling is causing the quakes.
No damage or injuries have been reported in any of the tremors.
Cleburne, a town of about 22,000 people, is about 50 miles southwest of Dallas.