Earthquakes Linked to Quest for Oil & Gas - U.S Maps

The United States Geological Survey released its first comprehensive assessment of the link between thousands of earthquakes and oil and gas operations, identifying and mapping 17 regions where quakes have occurred

The report was the agency's broadest statement yet on a danger that has grown along with the nation's energy production.

By far the hardest-hit state,the report said, is Oklahoma, where earthquakes arehundreds of times more commonthan they were until a few years ago because of the disposal of wastewater left over from extracting fuels and from drilling wells by injecting water into the earth. But the report also mapped parts of eight other states, from Lake Erie to the Rocky Mountains, where that practice has caused quakes, and said most of them were at risk for more significant shaking in the future.

"Oklahoma used to experience one or two earthquakes per year of magnitude 3 or greater, and now they're experiencing one or two a day," Mark Petersen, the chief author of the report, said. "Oklahoma now has more earthquakes of that magnitude than California."

The report came two days after Oklahoma's state governmentacknowledgedfor the first time the scientific consensus that wastewater disposal linked tooiland gas drilling was to blame for the huge surge in earthquakes there. The state introducedan interactive mapshowing quake locations and places where wastewater is injected into the ground, and the state-run Oklahoma Geological Survey said it "considers it very likely" that the practice is causing most of the shaking.

Hydraulic fracturing, a drilling technique that injects a high-pressure mix of water and chemicals into the ground to break rock formations and release gas, has drawn widespread attention. But injecting water to dispose of waste from drilling or production is a far greater contributor to earthquakes. The federal report excluded human activity, like mining, that can cause quakes but does not involve large-scale fluid injection.

In one of the 17 areas identified in the report, around Colorado's Rocky Mountain Arsenal, injections of chemical waste set off earthquakes starting in the 1960s. But the vast majority of the quakes since then have involved oil and gas production.

Many scientific reports, published over decades, have said that pumping fluids into the ground at high pressure can set off earthquakes. But until fairly recently, energy companies and regulators in some energy-producing states insisted that the link was still in doubt.

Most affected states have now acknowledged it, but Oklahoma had not until the recent statements by officials there. Still, state regulators around the country have not gone as far in controlling industry practices as environmental groups have asked, and there is little sign that the new federal findings will goad them to go farther.

Matt Skinner, a spokesman for the Oklahoma Corporation Commission, the state's top regulatory body for oil and gas exploration, said Oklahoma already required a "seismicity review" for proposed wells. "Any tool we can use in response to triggered seismicity," he said of the new report, "would be important to us."

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Asked about the report, Lawrence E. Bengal, director of the Arkansas Oil and Gas Commission, also pointed to what his state had already done, after a surge in earthquakes north of Little Rock in 2010 that made the state second only to Oklahoma in induced quakes.

The commission imposed a moratorium "prohibiting the drilling of any new disposal wells in the area where the earthquake activity had occurred," Mr. Bengal said, ordered the four active wells in the area plugged and ruled that seismic activity must be taken into account when allowing new disposal wells in other parts of the state.

Source: NY Times

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• Oil & Gas
• Environment
• Fracking