Rex Buchanan, interim director of the Kansas Geological Survey, told members of the House Energy and Environment Committee Tuesday that no evidence currently exists that the fracturing of rocks deep beneath the earth’s surface was producing earthquakes that can be felt.

Kansas has seen an increase in oil and gas exploration in southern counties as new technology allows extraction in difficult geological formations.

Hydraulic fracturing involves high-pressure injections of liquid into underground rock to release trapped fossil fuels.

Fracking has been suspected as a cause of increased seismic activity in parts of the U.S. that typically aren’t prone to earthquakes.