TULSA, Okla. (AP) – Oklahoma’s former lead seismologist says he felt pressured by a University of Oklahoma official to not link the state’s surge in earthquakes to oil and gas production.

The Tulsa World reports Austin Holland’s sworn testimony came in a lawsuit filed by a local resident against two oil companies for damages sustained during an earthquake in 2011.

University President David Boren and the former dean of university’s Earth and Energy College deny Holland was pressured by the school.

Researchers have linked the increased number of earthquakes in Oklahoma, Kansas, and Texas to the underground disposal of wastewater from oil and gas production.

Holland also testified he was reprimanded for helping write a peer-reviewed article on how to cope with such earthquakes. Boren says he couldn’t respond to specific comments Holland made because he hasn’t seen the testimony.