The increasing frequency of earthquakes in the shale fracking regions of America is spurring fears that this is due to the drilling of oil in rocks.
So far this year, Oklahoma has had more than twice the number of earthquakes as California, making it the most seismically active state in the continental US. As recently as 2003, Oklahoma was ranked 17th for earthquakes.
That shift has given rise to concern among communities and environmentalists that injecting vast amounts of wastewater back into the ground is contributing to the rise in Oklahoma’s quakes. The state pumps about 350,000 barrels of oil a day, making it the fifth largest producer in the US.
The rise in earthquakes isn’t just happening in Oklahoma, challenging scientists and regulators across the country. The growth of seismic activity alongside oil production in fracking states from Colorado to Ohio has sparked a series of studies tying the temblors to drilling activity. Most seismologists around the country are convinced that wastewater injected back into the ground is jolting fault lines and triggering earthquakes. Between 2006 and 2012, the amount of wastewater disposed in Oklahoma wells jumped 24 percent, to more than 1 billion barrels annually, according to the Oklahoma Corporation Commission, which regulates the industry.
“There’s a couple of good examples where I think it’s pretty clear that if you turn off the well the earthquakes stop,” said Justin Rubinstein, deputy chief of the US Geological Survey’s induced seismicity project “It’s a pretty strong correlation.”
Oil companies say the science isn’t far enough along and that correlation in activity does not amount to proof that their wastewater wells are causing the earthquakes.
“We’ve been doing injection in the state for a long time,” said Chad Warmington, president of the Mid-Continent Oil and Gas Association of Oklahoma. “It deserves a lot more investigation before making a determination.”
The development is important for the global oil industry as the US will remain the world’s biggest oil producer this year after overtaking Saudi Arabia and Russia as extraction of energy from shale rock formations surge.
The International Energy Agency (IEA) said in June that the US was the biggest producer of oil and natural gas liquids.
US production of crude oil, along with liquids separated from natural gas, surpassed all other countries this year with daily output exceeding 11 million barrels in the first quarter.
The rise in US oil production has had an impact on Nigeria.
Oil exports to the US from Nigeria fell 66 percent to 400,000 barrels a day at the end of 2013, from 1.2 million in 2005, according to the US government’s Energy Information Administration (EIA).
The oil and gas industry accounts for 75 percent of the Nigerian government’s revenue and up to 95 percent of dollar earnings.