In Oklahoma, major earthquakes—virtually unknown in the state until the fracking boom—depress property values.

A house in Moore, Oklahoma.

(Photo: Joe Raedle/Getty Images)

When people speak of the hidden costs of fracking, they're usually referring to health problems suffered by people living nearby, or long-term environmental consequences. But new research finds the practice—specifically the earthquakes it triggers—is also linked to more immediate losses.

Specifically, a decline in home prices.

It reports home values in Oklahoma—a state that has endured an exponential rise in earthquake activity since the hydraulic fracturing technology of oil and gas extraction was introduced—dip, sometimes dramatically, after the property has been rocked by a substantial earthquake.

"The recent change in seismicity rates, induced or not, has inflicted substantial costs on homeowners in Oklahoma," writes a research team led by Oberlin College economist Ron Cheung. Its study is published in the journal Regional Science and Urban Economics.

"Before 2010, Oklahoma had only a couple of earthquakes per year that were strong enough to be felt by residents," Cheung and his colleagues write. "Since 2010, seismic activity has increased, bringing potentially damaging quakes several times each year, and perceptible quakes every day."

To find whether this new reality has hurt property values, they looked at two sets of data covering the years 2006 through 2014—one featuring sale prices, and another noting the number of days a house is on the market.

Using data from the Oklahoma Geological Survey and the United States Geological Survey, "we link earthquake magnitude and the distance of a property to the earthquake epicenter" to determine the intensity of each quake for each piece of property.

"We estimate that prices decline by 3 to 4 percent after a home has experienced a moderate earthquake," they report. "Prices can decline 9 percent or more after a particularly damaging earthquake."

In addition, they found houses stayed on the market for significantly longer after earthquakes, presumably due to discomfort on the part of potential buyers.

"Wastewater injections do not necessarily lead to harmful seismic activities," the researchers write. "Careful and responsive regulatory practices may prove as effective in seismic risk mitigation as banning wastewater injection outright."

Putting such regulations in place will require political pressure. Homeowners whose property values have decreased may be particularly inspired to call their Congressional representatives and demand action.