Although the cause is under debate, the fact is Oklahoma ranks second in seismic activity in the continental United States according to analysis done by EnergyWire.
Joe Wertz for StateImpact Oklahoma reported ten percent of the earthquakes in the continental U.S. have occurred in Oklahoma.
240 earthquakes of a 3.0 magnitude or greater have been reported in Oklahoma since 2009. That level is the threshold at which people generally notice them.
Some link the increase in earthquakes to drilling and related activity, while others are skeptical.
The rest of the story can be found here.