Study finds earthquakes continue for years after gas field wastewater injection stops | Margaret Allen

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Study area for the DFW Airport earthquake sequence. Yellow triangles are the 2008-2009 SMU operated stations. Blue asterisks are the earthquakes reported by the 2013-2016 SMU earthquake catalog, indicating continued seismicity at the DFW Airport -- its boundaries indicated by the dotted blue-green line. Solid black line is the DFW Airport fault. Credit: SMUStudy area for the DFW Airport earthquake sequence. Yellow triangles are the 2008-2009 SMU operated stations. Blue asterisks are the earthquakes reported by the 2013-2016 SMU earthquake catalog, indicating continued seismicity at the DFW Airport -- its boundaries indicated by the dotted blue-green line. Solid black line is the DFW Airport fault. Credit: SMUStudy area for the DFW Airport earthquake sequence. Yellow triangles are the 2008-2009 SMU operated stations. Blue asterisks are the earthquakes reported by the 2013-2016 SMU earthquake catalog, indicating continued seismicity at the DFW Airport -- its boundaries indicated by the dotted blue-green line. Solid black line is the DFW Airport fault. Credit: SMUStudy area for the DFW Airport earthquake sequence. Yellow triangles are the 2008-2009 SMU operated stations. Blue asterisks are the earthquakes reported by the 2013-2016 SMU earthquake catalog, indicating continued seismicity at the DFW Airport -- its boundaries indicated by the dotted blue-green line. Solid black line is the DFW Airport fault. Credit: SMU

Feb. 13, 2018 (Phys.org) -- Efforts to stop human-caused earthquakes by shutting down wastewater injection wells that serve adjacent oil and gas fields may oversimplify the challenge, according to a new study from seismologists at Southern Methodist University, Dallas.

The seismologists analyzed a sequence of earthquakes at Dallas Fort Worth International Airport and found that even though wastewater  was halted after a year, the earthquakes continued.

The sequence of quakes began in 2008, and wastewater injection was halted in 2009. But earthquakes continued for at least seven more years.

"This tells us that high-volume injection, even if it's just for a short time, when it's near a critically stressed fault, can induce long-lasting seismicity," said SMU seismologist Paul O. Ogwari, who developed a unique method of data analysis that yielded the study results.

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