Chances of so many in such a short time are `` `` Powerball kind of odds , '' scientist says . One since two years ago were centered near Morrilton , Morrilton . More than two dozen suspect is natural gas exploration using hydraulic fracturing , known as fracking . `` We ca n't rule out the possibility that there may be a relationship , '' official says .
Chances of so many in such a short time are `` Powerball kind of odds , '' scientist says . More than two dozen since Wednesday were centered near Morrilton , Arkansas . One suspect is natural gas exploration using hydraulic fracturing , known as fracking . `` We ca n't rule out the possibility that there may be a relationship , '' official says .