Fracking could be behind recent spike in Oklahoma earthquakes
Monday, May 12, 2014, 6:05 - Since October 2013, seismologists have documented a nearly 50 percent spike in earthquake activity in Oklahoma, significantly increasing the chance for a damaging tremor to occur.
A recent U.S. Geological Survey and Oklahoma Geological Survey analysis has revealed that 145 earthquakes of magnitude 3.0 or greater occurred in Oklahoma between January and May 2, 2014, replacing the previous annual record of 109 earthquakes set back in 2013.
The spike in activity is especially alarming when compared to the 1978-2008 average earthquake rate of only two magnitude 3.0 or larger earthquakes per year.
“While it’s been known for decades that Oklahoma is 'earthquake country' we hope that this new advisory of increased hazard will become a crucial consideration in earthquake preparedness for residents, schools and businesses in the area,” said Dr. Bill Leith, Senior Science Advisor for Earthquakes and Geologic Hazards at USGS, in a statement.
“Building owners and government officials should have a special concern for older, unreinforced brick structures, which are vulnerable to serious damage during sufficient shaking.”
WHAT IS CAUSING THE SPIKE IN ACTIVITY?
Experts appear to be pointing the at fracking, or hydraulic fracturing.
This process involves injecting a mix of water, chemicals and sand deep into the ground to extract natural gas from shale rock.
"This phenomenon is known as injection-induced seismicity, which has been documented for nearly half a century, with new cases identified recently in Arkansas, Ohio, Texas and Colorado," The USGS writes.
"A recent publication by the USGS suggests that a magnitude 5.0 foreshock to the 2011 Prague, Okla., earthquake was human-induced by fluid injection; that earthquake may have then triggered the mainshock and its aftershocks ... studies also indicate that some of the earthquakes in Oklahoma are due to fluid injection.."
The 2011, magnitude 5.6 Prague earthquake was the largest in Oklahoma’s history, damaging a number of homes and buildings.
In response to the increased seismicity, the Oklahoma Geological Survey and the USGS have increased the number of monitoring stations and are actively working to quantify the increased hazard potential in central Oklahoma.