MEDFORD, Okla., Oct. 10 (UPI) — Residents of northern Oklahoma and southern Kansas woke to rumbles early Saturday morning, the reverberations of a slipping fault.
The earthquake, which struck at 4:20 a.m. local time, registered 4.4 on the Richter Scale. Its epicenter was located 11 miles from Medford, Okla., a small town not far from the Kansas border.
The quake could be felt as far south as Stillwater, Okla., and as far north as Wichita, Kan. Vibrations emanated from faulting in bedrock four miles beneath the surface.
No cause has been officially determined, but it is possible the quake was encouraged by human activity. Research suggests the frequency of small to medium quakes throughout the Midwest and Plains States has risen along with the growing presence of hydraulic fracturing, or fracking, operations.
Oklahoma has experience nearly 3,000 small earthquakes since 2008.
“There is evidence that some central and eastern North America earthquakes have been triggered or caused by human activities that have altered the stress conditions in earth’s crust sufficiently to induce faulting,” officials at the U.S. Geological Survey wrote.
In addition to fracking, dam construction, mining and quarrying operations can also induce faulting deep in the Earth.
