COLUMBUS, Ohio - The Ohio Department of Natural Resources has ordered the shutdown of two brine injection wells in Weathersfield Township while it investigates an earthquake at the well site.

The United States Geological Survey recorded the 2.1 magnitude tremor Sunday afternoon. The epicenter was determined to be at the site of the two class II brine injection wells along State Route 169 that have been operated by American Water Management since earlier this year.

According to the USGS, earthquakes of magnitudes between 1 and 3 are rarely felt by most humans.

ODNR spokesperson Bethany McCorkle issued the following statement on Friday:

“Due to the seismic array proactively placed in the area, ODNR was able to determine that possible evidence exists linking the American Water Management Services' injection well operation to a recent 2.1 seismic event. This is a relatively minor event, but out of an abundance of caution, ODNR issued chiefs orders to the company to suspend injection operations while a full investigation takes place.

The company has cooperated with our request and the two injection wells on site remain closed. We will continue to evaluate all the data to determine what exactly happened and will share more information as it is available.”

The Weathersfield wells are capable of disposing between 6,000 and 8,000 barrels of gas and oil field brine per day according to the American Water Management Services website. The company says the location also has room for two more wells if needed.

The ODNR regulates class II wells, which are used to inject fluids, primarily oil-field brine, into deep, underground geological formations for disposal or for secondary oil recovery. Oil-field brine is a saline by-product generated during oil and gas well operations.

On December 31, 2011, a 4.0 magnitude earthquake was reported in Youngstown. Some research linked that tremor to a class II brine injection well which was closed as a result.

Before last Sunday, the last earthquakes in the valley were reported in early March, when several tremors were recorded in the area of gas wells near the Carbon Limestone Landfill in Poland. Five earthquakes were measured over the course of two days at that time.

As a result, the Ohio Department of Natural Resources initiated a moratorium on permits for hydraulic fracturing wells. In addition, existing wells in that area are not permitted to do any new drilling or fracturing.

Dr. Raymond Beiersdorfer is a Geology Professor at Youngstown State University and questions some of the practices of the oil and gas industry.

"One of the things we've learned with these injection earthquakes is that's where they start. They're 2's and then they'll build up. The Youngstown earthquakes 3 years ago started with a two and we wound up with a 4. The Poland earthquake started with a 2 and wound up with 3's until they stopped it. So I think it's prudent we need to stop it at that." said Beiersdorfer.

Dr. Beiersdorfer points out that the ODNR recently gave operators of the Weathersfield wells permission to increase pressure at the site.

The statement from the ODNR did not disclose how long it would take to complete the investigation of the quake near the Weathersfield wells.