Oklahoma is now as earthquake-prone as California thanks to oil and gas drilling
Homeowners in Oklahoma and parts of Kansas now stand as great a chance of suffering earthquake damage in the coming year as do residents of more well-known earthquake states like California, according to a new federal assessment.
The assessment — a first of its kind effort to include human-caused earthquakes — comes in response to an alarming spike in the number and intensity of earthquakes in the central and eastern U.S. Scientific studies have tied the spike to the common practice of injecting wastewater into the ground during oil and gas drilling.
You May Also Like
The report shows how the oil and gas boom — which has vaulted the U.S. to the top of the global list of oil and gas producers — has come with a shaky side effect, altering the seismicity of the country and causing the number of damaging earthquakes to skyrocket.
According to the report, 7 million people now live in areas with induced earthquake activity, otherwise known as human-caused earthquakes. These hot spots are most heavily concentrated in Arkansas, Colorado, Kansas, New Mexico, Oklahoma and Texas.
Areas in the New Madrid fault zone — including parts of Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri and Tennessee — where a series of magnitude 7 to 8 earthquakes struck during 1811 and 1812, also saw an increase in earthquake risk, though this is thought to be naturally-driven, the USGS said.
Mark Petersen, the chief of the national seismic hazard modeling project in Golden, Colorado, said the uptick in seismic risk in parts of the central and eastern U.S. is likely "primarily related to the disposal of wastewater.”
Wastewater injection, he said in a March 28 press conference call, causes fluid to course through underground rocks, increasing pressure under the surface. Such activity can "unclamp" faults and release energy through earthquakes, he said.
According to the USGS report, during the past six years, the central U.S. has gone from an average of 24 magnitude 3 or greater earthquakes per year, based on the 1973 to 2008 average, to 688 such quakes in 2014 alone.
In Oklahoma, the poster state for human-caused tremors, the Oklahoma Geological Survey has found that the frequency of magnitude 3 or stronger earthquakes vaulted from one-and-a-half per year before 2008 to an astonishing two-and-a-half per day in 2015.
The 2015 rate was "approximately 600 times the historical background," the agency said in a report released on April 21, 2015, before concluding that the increase was "very unlikely to represent a naturally-occurring rate change and process."
These earthquakes aren't just small tremors, either.
In February, for example, Oklahoma recorded a 5.1 magnitude earthquake near Fairview that is thought to have been triggered by wastewater injection activity, demonstrating the potential for large earthquakes to be set off by industrial activities.
Petersen said that since a 50-year damage hazard map was released in 2014, the risk of damage in the wastewater injection areas have probably increased tenfold.
“This is because of the higher rates of the earthquakes we’re observing now versus how much we’ve observed previously,” he said.
In north-central Oklahoma and southern Kansas, for example, the new report shows there is as high as a 12% chance of damage from ground motion associated with an earthquake during 2016. This is comparable to high-hazard sites in California, including in the Los Angeles and San Francisco areas, where the risk is from naturally-occurring tremors.
The higher hazard levels in areas with active wastewater injection sites include locations within Oklahoma, Kansas, Colorado, New Mexico, Texas and Arkansas, the USGS found.
Arkansas, Kansas and Ohio saw dramatic reductions in man-made quakes when those states tightened restrictions on wastewater injections, according to Justin Rubinstein, the deputy chief of the USGS' earthquake hazards mapping program
Oklahoma Gov. Mary Fallin said the research justifies action taken by Oklahoma earlier this year to cut back on injections.
"Recent declines in produced wastewater disposal in Oklahoma are not reflected in the USGS map," Fallin said.
Petersen said new data is still coming in from the Oklahoma Geological Survey, and this may alter the level of risk.
"This gives us even a stronger base in going forward and gives state regulators further justification for what they are doing," Fallin said, according to the Associated Press.
Concern in Oklahoma is especially large considering the world's largest oil storage facility is located in Cushing, Oklahoma, and was not built to withstand strong earthquakes.
That facility has been nearly at capacity for much of the past year due to the low price of oil and glut in U.S. and global production.
Andrew Freedman is Mashable's Senior Editor for Science and Special Projects. Prior to working at Mashable, Freedman was a Senior Science writer for Climate Central. He has also worked as a reporter for Congressional Quarterly and Greenwire/E&E Daily. His writing has also appeared in the Washington Post, online at The Weather Channel, and washingtonpost.com, where he wrote a weekly climate science column for the "Capital Weather Gang" blog. He has provided commentary on climate science and policy for Sky News, CBC Radio, NPR, Al Jazeera, Sirius XM Radio, PBS NewsHour, and other national and international outlets. He holds a Masters in Climate and Society from Columbia University, and a Masters in Law and Diplomacy from The Fletcher School at Tufts University.
