Report: Fracking could raise earthquake risks in California

HOUSTON — A potential boom in hydraulic fracturing in California would increase the risk of earthquakes in the state, according to a report that environmental groups released Thursday.

Oil companies have shown great interest in California’s Monterey Shale, which could hold more than 15 billion barrels of oil. The Monterey Shale is located under the San Joaquin Valley, stretching across most of central California.

“Oil and gas production results in billions of gallons of contaminated wastewater that is often disposed of in underground injection wells,” according to the report, from Earthworks, Clean Water Action and the Center for Biological Diversity. “In many parts of the eastern and central United States where fracking and wastewater injection have boomed, earthquake activity has increased dramatically. Some regions have experienced a 10-fold increase in earthquake activity.“

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Most earthquakes linked to wastewater disposal wells have been too small to be noticeable by humans.

The report argued that “California is uniquely vulnerable to seismic events,” with many of the largest economic losses related to earthquakes stemming from the state.

The locations of faults near oil and gas developments further increases the risk. More than half of all active wastewater injection wells in California are located close to faults, the report said. However, it did not say whether any of those injection wells had resulted in earthquakes.

“No studies to date have evaluated the increased risk of induced earthquakes from California’s existing wastewater injection wells,” the report said. “There are fundamental knowledge gaps in understanding the risks of induced seismicity from these wells.”

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