TOPEKA, Kan. (AP) — A state geologist says a limit on the injection of saltwater into the ground by oil producers coincided with less intense earthquakes in south-central Kansas.

Interim director of the Kansas Geological Survey Rex Buchanan says the reduction in earthquakes’ magnitudes mirrored the adoption of the Kansas Corporation Commission’s injection restraints in March. But he says a drop in drilling due to falling oil process and a potential lack of tension along fault lines are other probable factors.

The Topeka Capital-Journal reports that the Kansas Corporation Commission is expected to renew another six months of injection restraints in Harper and Sumner counties.

The injection restraints were inspired by the proliferation of earthquakes in the area. About 125 earthquakes shook Kansas in 2014.