But are the fears justified?

First Sign of Trouble

Youngstown resident and geology professor Susie Beiersdorfer spends much of her free time organizing rallies against natural gas drilling. When a 4.0 trembler shook Youngstown last New Year’s Eve, she was in the middle of putting together a brochure describing the risks of fracking – the process of fracturing rock formations deep underground to release and extract the gas. It was a coincidence she wouldn’t let go to waste.

“Had one panel left, looking into the jobs and the economy and those statistics and myths and the earthquake hit, so we used that last panel to say the creation of this flyer has been interrupted by an earthquake with the 4.0 and some of that information.”

Although there had been a handful of smaller tremors earlier that year, Beiersdorfer says the shaking from this one caught people off guard.

The glass of the downtown deli we were at just sort of moved back and forth, it didn’t break. And the people walking in front just kind of stopped! It was definitely felt by everyone around there.

Concerns Turn to Disposal Well

It turns out, investigators attributed the quake not to a fracked natural gas well, but to a well used to store wastewater from the fracking process, called an injection well.

David Zeng is chair of the civil engineering department at Case Western Reserve University. He says the fault lines that cause earthquakes are usually located more than twenty miles below ground. Oil and gas wells where fracking occurs are much shallower – only one or two miles deep – and typically won’t trigger an earthquake.

“Of course during the hydro-fracking process, you may feel a ground vibration, but the ground vibration is relatively small, it’s not going to cause any noticeable damage to structures,” Zeng says.

But, Zeng says the injection wells used to store the used waste water from fracking are a different story.

“When you use injection wells, typically you are injecting waste water into the ground, so you want it really to go deep so that it won’t by any chance come back to affect your aquifer, your ground water. So typically it goes pretty deep – several miles.”

When you go several miles deep, then you can touch the fault that can cause an earthquake.

A Statewide Issue

The nearby well blamed for the New Year’s Eve quake and several smaller ones was immediately shut down, and the Ohio Department of Natural Resources placed a moratorium on using similar wells within a seven mile radius.

But, statewide the use of more than 170 injection wells continues. This summer, Governor John Kasich issued new regulations to better monitor wells and test their likelihood of triggering earthquakes.

While the regulations may help, it’s the unknowns that still concern environmentalists and activists like Susie Beiersdorfer. She says scientists haven’t studied the geology underneath Ohio well enough.

And if there is a fault, a non-documented, undiscovered fault, it could trigger an earthquake.

Drilling Continues

More injection wells are on the drawing board in Ohio to accommodate the needs of and drillers from out-of-state – mainly Pennsylvania and West Virginia – who ship their wastewater here for disposal. Currently that’s where most of Ohio’s buried wastewater comes from.

Julie Shemeta, a geophysicist who consults with drilling companies about triggering earthquakes, says it’s hard to predict just what that impact will be.

“We know that seismic activity has been pretty rare, and that it should continue to be rare. But the long term effects of significant increases in the number of waste water disposal wells, for induced seismicity, we really don’t know,” Shemeta says.

One thing that is for certain—the fracking activity isn’t going to let up any time soon. Over one hundred fifty horizontal gas wells have been drilled in the Utica Shale since 2009, and the state is on track to review permits for 33 new injection wells later this year.

The injection well, located in the Youngstown area, is used to dispose of brine that’s a byproduct of oil and gas drilling. Thousands of gallons of brine are injected into the well daily.

Ten earthquakes have occurred this year within two miles of the well. Each registered at 2.7 magnitude or lower.

The department told The Associated Press more detailed data from Columbia University about a Christmas Eve quake prompted the agreement. And injections were halted as a precaution, so potential links with earthquakes can be assessed.

Ohioans generally don’t have to worry too much about earthquakes. But recently, earthquakes have become almost commonplace in northeastern Ohio. Of the 10 earthquakes in Ohio this year, nine of them happened around the same general region around Lake Erie. The most recent quake occurred Tuesday about 40 miles east of Cleveland. It was centered in Lake Erie, just three miles from the village of North Perry. It was a minor quake that did not result in any reported damage.

The earth shook at around four o’clock.

“There definitely was a rumbling that scared me,” said Perry, OH florist Sharon Redlin. She was napping in her home.

“I was laying on the couch almost snoozing, and I actually felt movement, and it was kind of a loud rumbling sound was what I heard.”

At first, Redlin thought it might’ve been the noise of nearby construction work.

It’s still unknown what this recent increase in seismic activity may mean. The Ohio Seismic Network monitors seismic activity throughout the state. Network Coordinator Michael Hansen says there’s a sense of complacency in Ohio about earthquakes because they are relatively rare. Big, damaging quakes in the Midwest may be separated by decades, centuries, or even thousands of years. But Hansen also notes there have been about 200 earthquakes in Ohio since 1776, when people first began recording them.

Only within the past few years have scientists begun to really learn about Ohio’s subterranean rumblings.

“This is the first time we’ve had state-wide monitoring of earthquakes and we’re not only recording more earthquakes, but we’re really beginning to learn a great deal about what is beneath us,” Hansen says.

The first seismic monitor was installed in 1999, when funding first became available to monitor state-wide activity. With each earthquake, scientists can map fault lines that run through the state. They cannot predict when an earthquake might occur. But Hansen says once they collect more data about fault lines, they might be able to predict how big an earthquake could be.

Still, Ohioans won’t have to worry as much as people who live in places like the west coast, where there are frequent and severe earthquakes.

Places with a lot of seismic activity are where separate tectonic plates meet. Tectonic plates make up the Earth’s surface, and when they move and rub against each other, they cause earthquakes. The boundary of the tectonic plates forms a deep cut into the Earth’s surface. Hansen says these sorts of deep geological cuts once existed in Ohio about a billion years ago. Now, all that remains are scars. And it’s these ancient scars that are the current cause of seismic activity in Ohio.

“These are ancient features that are buried deep beneath us. Limestone and shale and so on cover these things over. But these are zones of weakness, and as the Atlantic ocean gets wider along the mid-Atlantic ridge, it’s pushing the North American continent westward so those stresses are accumulating in the continent and they’re relieved along these ancient zones of weakness,” Hansen says.

He says the accumulating stress can cause slippage of the rocks, leading to earthquakes. Although we probably don’t need to worry about a massive earthquake in the near future, we don’t know anything for sure. “There probably is a low probability of a damaging earthquake in the state, but it certainly isn’t a zero probability,” says Hansen.

The largest earthquake recorded in Ohio occurred in 1937 near the western Ohio town of Anna. It had a magnitude of 5.4, damaging chimneys, and cracking walls and foundations.