Drilling Is Making Oklahoma as Quake Prone as California
Californians have lived with the risk of a damaging earthquake for centuries. Now Oklahomans, and some Kansans, face the same threat, federal seismologists said on Monday.In an assessment released by the United States Geological Survey, experts said the chance of a destructive temblor in the next year is as great in parts of north-central Oklahoma and southern Kansas — where oil-and-gas operations have set off man-made quakes for about five years — as it is in the shakiest parts of quake-prone California.
The warning came in the agency’s map of earthquake risks, a document that for the first time included the prospects for human-caused quakes.
“By including human-induced events, our assessment of earthquake hazards has significantly increased in parts of the U.S.,” Mark Petersen, the chief of the agency’s Natural Seismic Hazard Mapping Project, said in a news release.
Four other states where waste disposal has led to human-induced quakes — Texas, Colorado, New Mexico and Arkansas — face considerably smaller risks of damaging tremors, the agency said. About seven million people live in the areas at risk of a human-induced earthquake, most of them in Oklahoma and Texas.
Over the last 15 years, those states have experienced an explosion in oil and gas production, which releases huge amounts of toxic wastewater. That wastewater is disposed of by re-injecting it into the ground, into rock formations thousands of feet below the surface, increasing the pressure on existing subterranean faults, and causing them to slip and produce tremors.