While these kinds of earthquakes don’t factor into building-code maps, they are a definite hazard to buildings, bridges, pipelines and other crucial structures, the USGS reports, according to CNN Money. This survey is the first time, in fact, that the government has designed maps that illustrate the risk of man-made earthquakes, also known as “induced” earthquakes. The agency defined this as tremors occurring in a region with increased earthquake rates that are attributed to “human activities, such as fluid injection or extraction.”
Considered highly controversial, fluid injection is a process used in hydraulic fracturing, or “fracking,” which has caused a huge uptick in U.S. oil and gas production. As oil and gas are pumped out of the ground, salty water often comes out as well. The water is usually injected back using high pressure in disposal wells, and it’s this practice that can induce earthquakes, according to the USGS.
In the fracking process, millions of gallons of water, mixed with sand and chemicals are blasted underground to break up shale deposits and release natural gas, USA Today reports.
As if to confirm the government’s findings, a 4.2 magnitude earthquake struck central Oklahoma near the Logan County town of Crescent just before midnight Monday, CBS News reports. An earlier 2.9 magnitude quake struck about nine miles east-northeast of Enid about 10:30 p.m.
There were no initial damages or injuries reported.
The temblors occurred on the same day as the release of the USGS survey, which found that Oklahoma has a one-in-eight chance of damaging quakes in 2016, which beats out California as the state with the highest likelihood.
Mark Petersen, Chief of the USGS National Seismic Hazard Mapping Project said high shaking and damage in the areas of the six states, mostly from induced earthquakes have been documented.
“Furthermore, the USGS Did You Feel It? website has archived tens of thousands of reports from the public who experienced shaking in those states, including about 1,500 reports of strong shaking or damage,” he said.
There’s been a surge of earthquake activity this year, averaging 2.5 shakers per day. Prior to 2008, Oklahoma averaged about one and a half per year.
And the majority of geologists say the spike in earthquakes is due to the state’s oil and gas industry, especially its disposal of enormous amounts of water into underground caverns.
But according to CBS, the industry refutes this. Even so, the Oklahoma Corporation Commission has requested a reduction of more than 500,000 barrels of wastewater each day, which is about 40 percent less than earlier levels.
Regulators say the either the volume should be reduced, or some of the disposal wells should be shut down, and last month, Governor Mary Fallin approved the use of nearly $1.4 million in state emergency funds for state agencies that are trying to reduce the number of earthquakes resulting from wastewater disposal, CBS News reports.
However, the oil and gas industry is an influential economic and political force, and operators have resisted cutting back on the injections of wastewater.
And one industry group says there are only a tiny percentage of injection wells causing the quakes, USA Today reports.
Katie Brown, a spokesperson for Energy In Depth, a program of the Independent Petroleum Associate of America, noted that “the vast majority of injection wells aren’t associated with earthquakes, a fact that’s confirmed by the U.S.Geological Survey’s report.”
“Data from the USGS and peer-reviewed studies show that fewer than one percent of injection well nationwide have been even potentially linked to small earthquakes,” she added.
“This is a complex issue, and most earthquakes are not induced. But this is also an issue that scientists say — with near uniformity — can be effectively managed,” she said.
However, according to CNN Money, the USGS says that a number of damaging earthquakes have recently occurred near injection wells. One magnitude 5.6 earthquake caused minor injuries and damaged homes in 2011 near Prague, Oklahoma. Other temblors in these fracking regions included a 5.3 magnitude quake outside Trinidad, Colorado in 2011. Another 4.8 quake struck near Timpson, Texas in 2012.
In Oklahoma City and the surrounding regions, there’s a 5 percent to 12 percent chance of damage from an earthquake this year, the USGS report said. That rate is higher than anywhere else in the U.S. mainland, except for parts of California that are estimated to face the same risks — but in California’s case, the risks are natural, not man-made.
And, of course, like all earthquakes, man-made ones are a challenge to predict. The USGS noted high levels of “uncertainties” in its forecast, and said that man-made quakes “can vary rapidly in time and space” due to changes in “industrial activity.”
The agency said its study didn’t explore the causes of increases in seismic activity and added that more research is necessary in that area. Also noted was the fact that some natural quakes may occur throughout its list of suspected man-made ones.
One research group, funded by the energy industry, pointed out that the geological agency didn’t directly reference fracking in its report.
