Earthquakes from fracking and drilling for oil have made Oklahoma, Kansas, Texas, Colorado, New Mexico and Arkansas nearly as quake-prone as naturally high-hazard areas of California, a report from the U.S. Geological Survey found.
The first-ever federal report to include an assessment of human-induced seismic shaking found 7 million people in the central and eastern U.S. live in the manmade earthquake zone, said Mark Petersen, head of the U.S.G.S. National Seismic Hazard Mapping Project.
Human activities, such as wastewater disposal from drilling for oil, can trigger earthquakes, the report, made public Monday, said. Fracking, or hydraulic fracturing, has spurred a boom in oil and natural-gas production. The fracking process blasts millions of gallons of water — mixed with sand and chemicals — deep underground to break apart shale deposits and release natural gas.
The central U.S. has seen the most dramatic increase in seismic activity over the past six years, the report found. From 1973 to 2008, before fracking became widespread, the USGS recorded more than 20 earthquakes of magnitude 3.0 and larger per year. Such events increased tenfold from 2009 to 2015 — to an average of 318 a year. In 2015, the USGS recorded 1,010 earthquakes.