A study performed by scientists from the University of Texas and Southern Methodist University and released on Wednesday says earthquakes which shook the Mid Cities area in the fall of 2008 may be linked to the disposal of saltwater generated by companies drilling for gas in the Barnett Shale. Dr. Brian Stump says drillers re-injected thousands of barrels of waste saltwater into disposal wells, and suggests that one disposal well near the Dallas Fort Worth Airport may have put stress on a fault line, causing the quakes.