Earlier this year, a report by the National Research Council in the United States found the controversial practice of hydraulic fracturing to extract natural gas was not a huge source of man-made earthquakes. However, the related practice of shooting large amounts of wastewater from "fracking" or other drilling activities into deep underground storage wells has been linked with some small earthquakes.
In an editorial accompanying the Lorca study, geologist Jean-Philippe Avouac of the California Institute of Technology said it was unclear whether human activity merely induces quakes that would have happened anyway at a later date. He noted that the strength of the quake appeared to have been greater than the stress caused by removing the groundwater.
"The earthquake therefore cannot have been caused entirely by water extraction," wrote Avouac. "Instead, it must have built up over several centuries."
Still, pumping out the water may have affected how the stress was released, and similar processes such as fracking or injecting carbon dioxide into the ground — an idea that has been suggested to reduce the greenhouse effect — could theoretically do the same, he said.
Once the process is fully understood, "we might dream of one day being able to tame natural faults with geo-engineering," Avouac said.
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Jordans reported from Istanbul. Ciaran Giles in Madrid and AP Science Writer Alicia Chang in Los Angeles contributed to this report.
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