Before a series of small quakes on Halloween 2008, the Dallas area had never recorded a magnitude-3 earthquake, said Cliff Frohlich, associate director and senior research scientist at the University of Texas at Austin's Institute for Geophysics. USGS data show that, since then, it has felt at least one quake at or above a magnitude 3 every year except 2010.
Frohlich said he doesn't think it's a coincidence that an intensification in seismic activity in the Dallas area came the year after a pocket of ground just south of (and thousands of feet below) the DFW airport began to be inundated with wastewater from hydraulic fracturing.
