PRAGUE — This central Oklahoma town of 2,400 claims two things as its own: Olympian Jim Thorpe and an annual kolache festival that honors its Czech heritage every May. Some locals here say the place should be known for a third: earthquakes.
“There’s been more than 10 or so,” since a magnitude 5.6 quake hit west of town in November 2011, damaging buildings and rattling nerves, said longtime resident Mark Treat, 54, sounding downright blase about them all.
Quakes with 3.4, 3.3, 3.1, 2.9 and 2.3 magnitudes have all rumbled near this town about 60 miles east of Oklahoma City in the past two years, and a new report by the U.S. Geological Survey suggests a quake “swarm” continues to plague central Oklahoma, which is far more accustomed to dealing with natural disasters that come from above than below.
Since January 2009, more than 200 magnitude 3.0 or greater earthquakes have hit central Oklahoma — marking a significant rise in the frequency of the seismic events, the survey reports. The study released Tuesday shows that one to three magnitude 3.0 earthquakes or larger occurred yearly in Oklahoma from 1975 to 2008, but the average grew to around 40 earthquakes per year from 2009-2013.
The swarm includes the 2011 quake, the largest ever recorded in Oklahoma, which damaged 200 buildings, shook a football stadium and could be felt throughout the state and in Arkansas, Kansas, Missouri, northern Texas and some parts of Illinois and Wisconsin. Until then, the biggest earthquake in the state had been a 5.5 magnitude temblor that jolted the city of El Reno, located just west of Oklahoma City, in 1952.
Scientists continue to study why the earthquake rate has changed so dramatically throughout this swath of Oklahoma — including possible links to wastewater disposal related to oil and gas production in the region.
Some researchers and environmental groups have long held that hydraulic fracturing, or “fracking,” — a process employed by energy companies that involves forcing millions of gallons of water, sand and other additives deep into the ground to free up pockets of natural gas — is a chief culprit for the rise in earthquake activity throughout Oklahoma and other states.