April 12 (Bloomberg) -- A spate of earthquakes across
the middle of the U.S. is "almost certainly" man-made, and may be caused
by wastewater from oil or gas drilling injected into the ground, U.S.
government scientists said in a study.
Researchers from the U.S. Geological Survey said that
for the three decades until 2000, seismic events in the nation's
midsection averaged 21 a year. They jumped to 50 in 2009, 87 in 2010 and
134 in 2011.
Those statistics, included in the abstract of a
research paper to be discussed at the Seismological Society of America
conference next week in San Diego, will add pressure on an energy
industry already confronting more regulation of the process of hydraulic
"Our scientists cite a series of examples for which an
uptick in seismic activity is observed in areas where the disposal of
wastewater through deep-well injection increased significantly," David
Hayes, the deputy secretary of the U.S. Department of Interior, said in a
blog post yesterday, describing research by scientists at the U.S.
Geological Survey. READ MORE