HARRISBURG, Pa. (KDKA/AP) – Pennsylvania environmental regulators released the findings of their investigation into a series of minor earthquakes that took place near fracking operations by an oil and gas company.

The temblors, all too weak to be felt by humans, were recorded last April in Lawrence County, about 50 miles north of Pittsburgh and three-quarters of a mile from a natural gas well owned by Houston-based Hilcorp Energy Co. No damage was reported.

READ MORE: State Senate Approves Bill Making It A Crime To Run Away From An Arresting Officer

The state Department of Environmental Protection has concluded that the series of seismic events that occurred on April 25, 2016, in Lawrence County can be related to operating activities.

Hydraulic fracking by the Hilcorp Energy Company caused four low magnitude earthquakes.

According to the DEP, the seismic events “showed a ‘marked temporal/spatial relationship’ to hydraulic fracturing activities at Hilcorp’s North Beaver NC Development well pad.”

The magnitude of the earthquakes ranged from 1.8 to 2.3. They were not felt on the surface, but were captured by seismometers. While they were considered micro-seismic, recommendations were made by the DEP during a Friday morning webinar.

“If any event of a two or greater is detected within a three-mile distance surrounding the wellbore path or well being stimulated, it is recommended the operator notify DEP in accordance with the previous established schedule and also discontinue hydraulic fracturing,” Seth Pelepko, of the DEP, said.

READ MORE: 'Run-Hide-Fight Really Does Work': Tree Of Life Survivor Audrey Glickman Wants Others To Remember 'It Can Happen Again'

The Hillcorp pad has four wells which is within a five-mile radius of the epicenters of the earthquakes.

Hilcorp has been given recommendations going forward.

“The recommendations were part of an ongoing development process and they were handed out in the September-October timeframe and so far, Hilcorp is complying with the recommendations,” Pelepko said.

Fracking has been tied to earthquakes in other states including neighboring Ohio, but never in Pennsylvania – until now.

Stay With KDKA.com For More Details

Join The Conversation On The KDKA Facebook Page
Stay Up To Date, Follow KDKA On Twitter

MORE NEWS: Community Garden In Pittsburgh Holds Volunteer Events To Help Community Heal After Tree Of Life Shooting

(TM and © Copyright 2017 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2017 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)