4.3-magnitude earthquake rattles central Oklahoma

EDMOND, Okla. (AP) – A strong, 4.3-magnitude earthquake awoke many people in the Oklahoma City area early Tuesday, the latest in a series of temblors that’s prompted state regulators to call for more restrictions on oil and gas operators in the state.

The quake struck at 5:39 a.m. near the city of Edmond, which is a suburb north of Oklahoma City, according to preliminary data from the U.S. Geological Survey. There are no immediate reports of major damage, but the quake is blamed for power outages affecting thousands of people.

A smaller earthquake with a preliminary magnitude of 3.4 hit the same area about 10 minutes later, the USGS said. Edmond city officials said about 4,400 homes and businesses lost power because of the quake but electricity was restored quickly.

Oklahoma has become one of the most earthquake-prone areas in the world, with the number of quakes magnitude 3.0 skyrocketing from a few dozen in 2012 to more than 720 so far this year. Many of the earthquakes are occurring in swarms in areas where injection wells pump salty wastewater – a byproduct of oil and gas production – deep into the earth.

In response, the Oklahoma Corporation Commission has begun reducing the volume or shutting down some disposal wells in hopes of curtailing the quakes.

The strongest earthquake on record in Oklahoma is a magnitude 5.6 centered in Prague in November 2011 that damaged 200 buildings and shook a college football stadium.