With real-time monitors, scientists have linked a swarm of small earthquakes west of Fort Worth, Texas, to nearby natural gas wells and wastewater injection.
"It's what we figured all along, it's not really new news to us," said Azle Mayor Alan Brundrett, "It's just confirming our suspicious that we've had."
In 84 days from November 2013 to January 2014, the area around Azle, Texas, shook with 27 magnitude 2 or greater earthquakes, while scientists at Southern Methodist University and the U.S. Geological Survey monitored the shaking. It's an area that had no recorded quakes for 150 years on faults that "have been inactive for hundreds of millions of years," said SMU geophysicist Matthew Hornbach.