Oklahoma had a fivefold surge in earthquakes last year, making it by far the most seismically active state in the Lower 48.
The Sooner State was shaken by 585 quakes of magnitude 3 and larger, compared with only 100 in 2013, according to an EnergyWire analysis of federal earthquake data. California, which is twice the size of Oklahoma, had fewer than one-third that number.
Researchers and many people in the state believe the quakes are
linked to oil and gas activity, namely deep-underground disposal of
drilling waste fluid.