Central Oklahoma from Oklahoma City to the Kansas border joins much of California as one of the areas most likely to experience an earthquake in 2016, according to a federal map that includes both natural and manmade earthquake risk zones for the first time.
The U.S. Geological Survey released the first map ever of manmade earthquake risk zones on Monday with its annual release of natural earthquake risk zones. Oklahoma is now among one of the most earthquake-prone portions of the country, with much of the central part of the state listed as an earthquake risk zone.
The portion from Oklahoma City to the Kansas line is listed as having a 5-10 percent chance of having an earthquake in 2016, which a small portion of Oklahoma given a 10-12 percent chance of feeling the ground shake, according to the study.
That’s almost entirely due to earthquakes caused by wastewater injection, or the process by which water from the oil and gas production process is injected into underground wells deep in the Earth’s crust. While many activists say hydraulic fracturing, or fracking, causes earthquakes, the study found fracking rarely causes earthquakes.
The study shows 21 spots throughout the country that have seen larger amounts of seismic activity due to human activity since 1980. In addition to Oklahoma, those areas are mainly in Kansas, Texas, Colorado, New Mexico and Arkansas. About 7.9 million people live within the affected areas.
“In the past five years, the USGS has documented high shaking and damage in areas of these six states, mostly from induced earthquakes,” said Mark Petersen, chief of the USGS National Seismic Hazard Mapping Project.
“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.”
California continues to be the state most at-risk from seismic activity, with much of the state between 1-12 percent at risk of an earthquake in the next year. That state’s seismic activity can be attributed to natural factors, such as the San Andreas Fault that runs through the state.
Justin Rubinstein, deputy chief to the USGS Induced Sesmicity Project, said the survey is still a long way off being able to distinguish between natural and human-induced earthquakes through scientific measurements.
He said currently it takes a bit of sleuthing to figure out when man causes an earthquake. Most of the time, the Geological Survey has to investigate whether wastewater injection or another activity that would influence seismic activity is taking place near the epicenter of a quake.
“There’s nothing we can do to immediately identify when we’re looking at the seismogram that this earthquake was induced,” he said, adding that is an area of scientific research.
The agency decided to come out with only a one-year projection for how humans are affecting seismic activity because the number of earthquakes can fluctuate depending on economic activity and regulations.
Rubenstein said some areas of the country saw the amount of seismic activity reduced after new regulations were put in place on wastewater injection. He said Kansas established regulations in March 2015 and has seen seismic activity drop in the intervening period.
Oklahoma has put in its own regulations, but it remains to be seen how they will affect earthquakes in the Sooner state.
“We have seen in other locations where new regulations, new restrictions on injections, have changed the locations of earthquakes,” he said.
