Oklahoma’s risk of earthquakes is as great as that of California, according to a new report released on Wednesday by the U.S. Geological Survey (USGS) forecast. In Oklahoma, much of the risk stems from man-made earthquakes, largely blamed on the oil industry’s practice of fracking. The report suggests that 3 million people in Oklahoma and southern Kansas could be threatened by earthquakes in 2017.
The Los Angeles Times reported that, according to USGS scientists writing in the journal Seismological Research Letters, the risk of earthquakes is so high in Oklahoma and southern Kansas that the chance of damage there is likely to be similar to quake damage in California. The largest earthquake ever recorded in Oklahoma, a 5.8 magnitude earthquake that struck near Pawnee happened in 2016.
Last year, one of the other moderate earthquakes that occurred in Oklahoma was a 5.0 temblor in November, which had an epicenter near Cushing, the self-proclaimed “Pipeline Crossroads of the World.” That earthquake was felt as far away as Fort Smith, Arkansas, and loose bricks were dislodged in chimneys and storefronts in Cushing, causing them to fall onto the sidewalks.
Fracking, or disposing of wastewater deep underground that is a byproduct of oil extraction by injecting it underground, is widely believed by scientists to cause earthquakes in Oklahoma. Fracking is not thought, though, to cause earthquakes everywhere it is practiced, like in North Dakota.
From 1980 to 2000, the average number of earthquakes in Oklahoma at a magnitude of 2.7 or stronger was about two. In 2014, with the increase of the practice of fracking in the state, the number of quakes jumped to 2,500 in 2014 and in 2015 hit 4,000 quakes.
There was a decrease in earthquakes in Oklahoma in 2016, down to 2,500. Coincidently, at the same time the amount of wastewater being injected underground decreased. That might be due to regulatory actions or because gas and oil extraction and demand has fallen with the falling prices of petroleum.
In 2016, Mark Petersen of the USGS stated that in some areas of Oklahoma, the amount of injected wastewater has been reduced by nearly 40 percent. Jeremy Boak, the director of the Oklahoma Geological Survey, said in a statement that low oil prices and wastewater injection rates and a curtail due to state directives help reduce the rate of seismic events and future widespread seismic activity.
Fox News reported that Petersen said, in the first months of 2017, the rates of earthquakes in Oklahoma decreased. He stated at a press conference on Wednesday, “This is exactly what we wanted.” Petersen added it might not ever come down to the levels of earthquakes Oklahoma had prior to 2008, which were much less than one a day. According to USA Today, Petersen said that this year’s forecast of natural and human-induced earthquakes is hundreds of times higher than in 2008 when rates rapidly increased due to induced seismic events.
Petersen said that the risk of earthquakes in Oklahoma in 2017 might be somewhat decreased from last year. However, he cautioned that there is still a significant chance for damaging quakes in the U.S.
In comparison with the seismic risk before 2009, the USGS report states the forecast earthquake hazard for 2017 is well elevated. This year, oil companies in Oklahoma are tapping deeper oil fields. Besides petroleum, the wells also bring up a large amount of salt water. This results in the oil companies dealing with more wastewater than previously.
With oil companies in Oklahoma dealing with wastewater by injecting it deeper into the earth, the number of quakes have risen in the state. Scientists believe that when oil companies practice fracking, injecting this wastewater deep underground, it changes the pressures on fault lines, which, in a way lubricates the faults, making them more likely cause an earthquake.
According to the USGS, the wastewater from fracking, when injected back into the ground, fills gaps in and around dormant faults, causing them to slip, causing quakes.
Federal scientists feel that Oklahoma will continue to see the biggest man-made earthquakes this year. The USGS report indicated that overall probability for an earthquake anywhere in either California or Oklahoma is relatively small, even with the increase in earthquakes due to fracking, stating that central California and portions of Oklahoma are looking at higher risks for a damaging quake in 2017.
Other regions and states in the United States that will have an elevated risk of earthquakes in 2017 include throughout much of the rest of California, Seattle, Washington, and along the New Madrid fault, where Tennessee Kentucky, Arkansas, Illinois, and Missouri come together.
According to Petersen, the New Madrid fault is a constant concern. He stated that is because the risk of an earthquake along the New Madrid fault is less, as in the case of Seattle and southern California, they each could see large, destructive, and deadly quakes.
The environmental groups the Natural Resources Defense Council and the Sierra Club want all fracking stopped. Besides potentially increasing the risk of earthquakes, on its website, the Sierra Club says that fracking can contaminate drinking water, as well as contribute to air pollution.
While the risk of earthquakes in Oklahoma has declined since last year, the USGS report forecasting the risks areas where earthquakes might hit in the United States in 2017 suggests that Oklahoma’s risk of having them is as great as California’s. Three million people might be at risk in southern Kansas and Oklahoma, according to the USGS report. The risk might be even higher, potentially affecting 4 million people.
By John Samuels