A federal report says earthquakes caused by humans are on the increase.
For the first time, the U.S. Geological Survey has unveiled a map of earthquakes thought to be triggered by human activity in the Eastern and Central United States.
Oklahoma is by far the worst-hit state recently, according to the USGS study released Thursday. The state last year had more earthquakes magnitude 3 or higher than California, part of a huge increase recorded in recent years.
Seismic activity in Texas near the Dallas-Fort Worth area has also increased substantially recently. Kansas, Colorado, New Mexico and Ohio have all experienced more frequent quakes in the last year.
All of the areas highlighted on the map “are located near deep fluid injection wells or other industrial activities capable of inducing earthquakes,” the study said.
Mark Petersen, chief of the USGS’ National Seismic Hazard Project, said the pattern of increased quakes is troubling.
“These earthquakes are occurring at a higher rate than ever before, and pose a much greater risk and threat to people living nearby,” Petersen said.
The American Petroleum Institute said the industry is working with scientists and regulators “to better understand the issue and work toward collaborative solutions.”
The release of the map comes as officials are coming to terms with the idea that wastewater disposal following oil and gas extraction is causing more earthquakes.
Hydraulic fracturing, or fracking, involves shooting a high-pressure mix of water, sand and chemicals deep underground to extract oil and natural gas.
The resulting wastewater is often forced underground as well, but can trigger earthquakes on faults that haven’t moved in a very long time.
The Oklahoma Geological Survey said Tuesday that the sharp rise in quakes in that state is “very unlikely to represent a naturally occurring process,” since they are occurring over the same area that saw a huge jump in wastewater disposal in the last several years.
The seismicity rate in 2013 was 70 times greater than the background seismicity rate observed in Oklahoma prior to 2008, state officials said.
Human-induced earthquakes have troubled scientists because they pose a risk to public safety — and because they have become larger.
A magnitude 5.6 earthquake believed to have been caused by wastewater injection hit near Prague, Okla., in 2011, injuring two people and destroying 14 homes.
That same year, a 5.3 earthquake struck a remote part of Colorado, near the town of Trinidad close to the New Mexico border, which the USGS said was also triggered by wastewater injection.
History suggests that even larger earthquakes could be in store.