The Texas Railroad Commission is requiring the operators of five disposal wells near a sharp earthquake to perform some tests.

In a statement Friday, the commission says Bosque (BAHS'-kee) Disposal Systems LLC, EOG Resources Inc., MetroSaltwater Disposal Inc. and Pinnergy Ltd have agreed to shut down the wells temporarily until results are in on the tests, which will be made within days. The testing will help determine the effect of wastewater injection into subsurface rock formations in the area where a 4.0 magnitude earthquake was centered Thursday about 30 miles southwest of Dallas

The quake was the sharpest ever detected in North Texas. It injured no one but caused minor damage to two mobile home foundations.