A university study analyzing a sequence of North Texas earthquakes has found that seismic activity can continue for years even after wastewater injection wells are closed in order to prevent them.
Researchers at Southern Methodist University said this week that high-volume injection near a critically stressed fault can "induce long-lasting seismicity."
The findings indicate that shutting down injection wells in reaction to earthquakes may not have the desired effect of immediately stopping them.
The researchers recently reported their findings in the peer-reviewed Journal of Geophysical Research.
They studied a series of quakes near Dallas-Fort Worth International Airport that began in 2008. Nearby wastewater injection was halted in 2009, but earthquakes continued for at least seven more years.
Researchers say the phenomenon isn't unprecedented: A similar outcome occurred near Denver in the 1960s.