Center for Biological Diversity

For Immediate Release, February 4, 2016

Contact: Patrick Sullivan, (415) 517-9364,

Study: Oil Industry Injections Caused California Earthquake Swarm

Research Is First Study to Document Wastewater-induced Quakes in California

LOS ANGELES— Oil industry wastewater injections caused a series of earthquakes in Southern California, according to a new scientific study that underscores the risks of extreme oil production practices in quake-prone California.

The research, published today in the journal Geophysical Research Letters, is the first scientific study to document oil industry wastewater-induced earthquakes in California. The study links a sudden surge in wastewater injection and a 2005 series of quakes near Bakersfield, Calif, that ranged up to magnitude 4.7. The authors note that “considering the numerous active faults in California, the seismogenic consequences of even a few induced cases can be devastating.”

“This study should push state officials to act immediately to protect Californians from oil industry-induced earthquakes,” said Shaye Wolf, a scientist with the Center for Biological Diversity. “The more oil companies frack and drill, the more wastewater they inject into disposal wells near active faults. That’s an absolutely unacceptable risk in our earthquake-prone state.”

Wolf coauthored a 2014 analysis that found that a majority of the oil industry’s wastewater injection wells are near active earthquake faults in California. The report, titled On Shaky Ground, found that oil companies are injecting billions of gallons of oil and gas wastewater a year into hundreds of disposal wells near active faults around Los Angeles, Bakersfield and other major cities.

Wastewater injection volumes in California doubled between 1995 through 2014, according to a Center analysis of figures from state oil officials, and 54 percent of California’s active wastewater wells are within 10 miles of a recently active fault.

The earthquakes examined in today’s study occurred about 5 miles from the injection wells linked to this seismic activity. At least 350 of California’s disposal wells, which are regulated by the state’s scandal-plagued Division of Oil, Gas and Geothermal Resources, are within 5 miles of an active fault.

“Our results suggest that induced seismicity may remain undetected in California without detailed analysis of local geologic setting, seismicity, and fluid diffusion,” the study authors note.

Scientists have concluded that injection of oil and gas wastewater can reduce the natural friction that pins faults in place, triggering earthquakes. Oil-industry wastewater disposal appears to have induced a 2011 quake in Oklahoma that injured people and destroyed more than a dozen homes, according to the U.S. Geological Survey.

“We need to halt extreme oil-production methods that help produce these huge volumes of wastewater and prohibit oil companies from drilling new injection wells before there are tragic consequences for people living near these faults,” Wolf said.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 990,000 members and online activists dedicated to the protection of endangered species and wild places.

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