For the past three decades, Oklahoma averaged about 50 earthquakes a year. But that number has skyrocketed in the past few years. In 2013 — the state's most seismically active year ever — there were almost 3,000.
The quakes are small, and they're concentrated in the central part of the state, where the Erwins live.
OK. The word fracking was added to the Merriam-Webster dictionary this month. It is defined as the injection of fluid into shale beds at high pressure in order to free up petroleum resources. Despite getting this official definition, both the spelling and meaning of fracking remain controversial. Marie Cusick, from member station WITF, reports.
MARIE CUSICK, BYLINE: This is a fracking site in northeastern Pennsylvania. It's one of the most productive parts of Marcellus Shale natural gas formation.