Earthquakes

When Austin Holland was being considered for his job as the sole seismologist at the Oklahoma Geological Survey in 2009, his interviewer posed a wry question: "Are you going to be able to entertain yourself as a seismologist in Oklahoma?" Back then, the state had a 30-year average of only two earthquakes of magnitude 3.0 or higher per year. As it turns out, though, boredom has been the least of Holland's concerns. Over the last five years, the state has had thousands of earthquakes — an unprecedented increase that has made it the second-most seismically active state in the continental United States, behind California. The state had 109 temblors measuring 3.0 or greater in 2013 — more than 5,000% above normal. There have already been more than 200 earthquakes this year, Holland said. Scientists say the more likely cause of the recent increase is underground injection wells drilled by the oil and gas industry. About 80% of the state is within nine miles of an injection well, according to the Oklahoma Geological Survey.