A 4.2 magnitude earthquake centered north of Oklahoma City hit Friday morning, the latest in a series of quakes that's prompted state regulators to call for more restrictions on oil and gas operators.

According the U.S. Geological Survey's website, the quake happened at 5:39 a.m. in an area 3 miles northeast of Edmond and 16 miles north-northeast of Oklahoma City.

There were no immediate reports of injury or damage.

Oklahoma has become one of the most earthquake-prone areas in the world, with the number of quakes magnitude 3.0 or greater skyrocketing from a few dozen in 2012 to more than 800 in 2015. Many of the earthquakes are occurring in swarms in areas where injection wells pump salty wastewater — a byproduct of oil and gas production — into the earth.