Texas is rocked by a series of earthquakes, the greatest of which is almost a magnitude 4.

In the rate of earthquakes and to the strongest earthquakes that have occurred in recent years.” But it wasn’t until 2015 that scientists realized fracking was the cause of the state’s earthquakes.

Researchers from Southern Methodist University examined 84 days between November 2013 and January 2014 and discovered that 27 earthquakes of magnitude 2 or higher occurred.

In the Azle region, which is where fracking is practiced. According to geophysicist Matthew Hornbach of Southern Methodist University,

The drilling and injection had a stronger correlation with the quakes’ time and position than any other potential cause.

USGS seismologist Susan Hough, who was not on the research team, said that there seems to be little question over the conclusion that the earthquakes were really generated.