vinton county oh
An earthquake around 12:24 p.m. on Wednesday near Elk Township of Vinton County had worried individuals calling 911.

"People were just wondering what was going on," said William Faught, the director of the Vinton County Emergency Management Agency, who also felt a tremor from the earthquake.

"It's the first indication that we have in our catalog of any earthquake occurring in Vinton County," said Jeff Fox, a seismologist at the Ohio Department of Natural Resources (ODNR).

He classified yesterday's earthquake at a 3.8 magnitude instead of the 3.4 magnitude that was reported through the U.S. Geological Survey (USGS). John Bellini, a geophysicist at the USGS, didn't think much of yesterday's event other than it being another sporadic earthquake. Bellini says yesterday's earthquake did not reach the level of intensity to do any real damage.

"The lower-end of what is capable of causing damage is in the mid-four (magnitude) range. So, around four and four-and-a-half you will start to see items knocked from shelves and stuff like that," said Bellini.

Fox stressed that the earthquake was one of these sporadic, natural occurrences.

"Researchers at Miami University ran some sophisticated algorithms on yesterday's event, and they've seen no clustering before this event happened - no pre-shocks or anything like that happened," said Fox. "[The earthquake is] kind of obeying the normal tectonic earthquake rules where it's the main shock followed by very small aftershocks".

But environmentalists aren't so sure, arguing the earthquake could be linked to injection wells in the area.

"We looked and saw how close the earthquake's epicenter was located to injection wells for fracking. In an eight to ten mile range, there were seven different injection wells," said Melanie Houston, Director of Oil and Gas at Ohio Environmental Council.

"We have put in an inquiry to the Ohio Department of Natural Resources and their Public Interest office, and we haven't received a response from them yet," she said.

There isn't clear, solid evidence injection wells cause seismic activity in Ohio, but environmentalists point to findings by state investigators suggesting a connection between wastewater injection wells and a series of earthquakes in the Youngstown area that happened in 2011.

A 3.0 magnitude earthquake in the Wayne National Forest last month also added to environmental concerns in the region because of shale well sites within five miles of the epicenter of that quake.

Bellini said wastewater produced from fracking is usually injected back into the earth through injection wells and can, in some cases, cause seismic activity.

Not only was this the first-recorded earthquake in the area, but it was also one of the deepest earthquakes to be recorded in the state.

"We've come to the conclusion that this earthquake was a pretty deep event, as it was close to 20 km in depth below the earth's surface," said Fox.

He said earthquakes of this type of depth were harder to analyze compared to more average earthquakes that typically have a depth of five to six kilometers.

"We've seen other indications of deep-focused earthquakes in that part of the state, and we're not really sure why earthquakes in that part of the state happen so deep; we don't have any images or seismic reflections or profiling being done down there."

Whether or not injecting fracking wastewater into the earth has caused earthquakes, Fox is certain that earthquakes will keep happening.

"We will experience more earthquakes; we have anywhere between a half-dozen to ten earthquakes a year in the state - around 2 magnitude and above. Whether we can predict if they will increase, that's impossible to tell," said Fox.

There were no reports of injuries or serious damages to properties.