Earthquakes in Oklahoma in the past week, including one of the strongest ever recorded in the state, have led to calls for the governor to make changes to oil and gas drilling regulations and reduce seismic activity scientists link to the energy industry.

 

Two large earthquakes were recorded in northwest Oklahoma on Wednesday, including a magnitude 4.8 quake. The quakes were part of a surge in seismic activity over the past several years.

 

Scientists have tied a sharp increase in the intensity and frequency of quakes in Oklahoma to the disposal of saltwater, a byproduct of oil and gas extraction, into deep wells. Oil fields have boomed in Oklahoma over the past decade thanks to advances in hydraulic fracturing and horizontal drilling.

 

Although the quakes last week caused no major reported damage or injuries, they left many Oklahomans shaken. Firms providing quake insurance saw a surge in calls inquiring about coverage.

 

U.S. energy companies are starting to react to rising seismicity around the world's largest crude storage hub in Cushing, Oklahoma, site of many disposal wells. The changes include new protocols for inspecting the health of crude tanks, potentially halting operations after temblors, and monitoring quake alerts.

 

The strongest quake recorded in Oklahoma was a magnitude 5.5 that struck in April 1952, the U.S. Geological Survey said.

 

 

PHOTO: Damage to a home in central Oklahoma after an earthquake.