Shutting down oil and gas wastewater injection wells may not stop human-induced earthquakes quickly, say seismologists. The scientists analyzed earthquakes at DFW Airport that began in 2008 and found that even though wastewater injection was halted after a year, earthquakes continued for at least seven more years. They concluded that high-volume injection, even for a short time, can induce long-lasting seismicity when it's near a critically stressed fault.