By Bob Weaver|
A 5.6 magnitude earthquake struck Saturday morning near Pawnee, Oklahoma, and rattled through at least six surrounding states in the US heartland, according to the US Geological Survey.
The earthquake was also felt in Kansas, Arkansas, Missouri, Texas, Nebraska, and Iowa, according to the USGS.
The Oklahoma Corporation Commission, a regulatory agency that examines the state's fuel, oil, gas, public utilities and transportation industries, is "reviewing disposal wells in the vicinity of the earthquake near Pawnee," Oklahoma Gov. Mary Fallin said.
The Oklahoma Department of Transportation is checking bridges for damage and structural engineers are assessing building safety.
There was a total of 11 earthquakes in the same area Saturday, the USGS said. The largest was at 7:02 a.m. (8:02 a.m. ET), with the preliminary 5.6 magnitude. The other quake magnitudes ranged from 2.7 to 3.6.
A recent report released by the USGS showed that people in parts of Texas and Oklahoma now face similar ground-shaking risks from human induced activity, such as high pressure fluid injection into disposal wells, related to gas and oil production.
Ongoing small earthquakes have been shaking Oklahoma and southern Kansas daily, linked to drilling and fracking,
according to geophysicist William Ellsworth of the U.S. Geological Survey.
Ellsworth said the hundreds of quakes are mostly in areas with energy drilling, often hydraulic fracturing, a process known as fracking. Many studies have linked the increase in small quakes to the process of injecting wastewater deep underground because it changes pressure and triggers dormant faults.
In West Virginia, a number of small earthquakes in Braxton and Gilmer counties have been declared unrelated to Marcellus drilling operations or the injection of millions of gallons of waste water used in fracking back into the earth, sites known as injection wells.
Ellsworth said his once stable region in the study is now just as likely to see serious damaging and potentially harmful earthquakes as the highest risk places east of the Rockies such as New Madrid (including Ohio Valley), Missouri, and Charleston, South Carolina, which had major quakes in the past two centuries.
"The more small earthquakes we have it just simply increases the odds we're going to have a more damaging event," Ellsworth said.
A 2011 earthquake in Prague, Oklahoma, was a 5.7 magnitude, causing some damage and hurting two people.
While some states have linked Marcellus-Utica operations to earthquakes, in West Virginia, Ronald McDowell, PhD, Senior Research Geologist and Head of Geoscience Section of the West Virginia Geological and Economic Survey said, "I do not suspect there is a connection to human activity."
"I believe it is highly unlikely there is any connection to drilling activities. That conclusion applies equally for vertical and horizontal drilling and any subsequent stimulation activity such as "fracking," McDowell said responding to inquiries from the Hur Herald.
Referring to the recorded quakes in Gilmer and Braxton counties, McDowell said, "This is, as far as I am concerned, a reaction of the old deep crust underneath the state of West Virginia, the stresses that have been built up for billions of years. Every once in a while those rocks let loose to relieve some of the stress."
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