New federal research says small earthquakes shaking Oklahoma and southern Kansas daily are dramatically increasing the chance of bigger and dangerous quakes.
Scientists link many of these quakes to the deep underground injections of wastewater after drilling for energy in a process known as hydraulic fracturing, or fracking.
Federal records show Oklahoma has had nearly 200 quakes that people have felt since Jan. 1.
U.S. Geological Survey geophysicist William Ellsworth says the jump in these nuisance quakes increases the risk of future ones that can do serious damage.
But Ellsworth said not all states with fracking and wastewater injections are seeing increased quakes and not all those with increased quakes are at a higher risk for major quakes. Arkansas for example is now seeing fewer man-made quakes.
The number of small quakes started rising in 2008, then soared in 2013 and 2014.
Meanwhile, Saturday, several earthquakes were recorded in northern Oklahoma.
The U.S. Geological Survey reports five quakes ranging in magnitude from 2.6 to 3.7 were recorded Saturday in an area between Medford and Cherokee. The epicenters were located from about 20 to about 35 miles north of Enid.
Sheriff's offices in Grant and Alfalfa counties say there are no reports of damage or injury.
Geologists say earthquakes of magnitude 2.5 to 3.0 are general the smallest that are felt by humans and that damage isn't likely in earthquakes below magnitude 4.0
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