The number of earthquakes in the central United States rose „spectacularly“ near where oil and gas drillers disposed of wastewater underground, a process that may have caused geologic faults to slip, U.S. government geologists report.

The average number of earthquakes of magnitude 3 or greater in the U.S. midcontinent – an area that includes Arkansas, Colorado, Oklahoma, New Mexico and Texas – increased to six times the 20th century average last year, scientists at the U.S. Geological Survey said in an abstract of their research.