Oklahoma City suffered about a dozen earthquakes in less than a week and this prompted the state's oil and natural gas regulator to reduce targets on wastewater disposal volume. The Oklahoma State Commission has directed injection well operators to reduce wastewater disposal. The regulator has prepared an action plan for injection wells located in the area that was hit by earthquake.

Within a span of week, a series of earthquakes hit Edmond area in north of Oklahoma City.  Oil and Gas Conservation Division Director Tim Baker said: "We are working with researchers on the entire area of the state involved in the latest seismic activity to plot out where we should go from here."

The latest occurrence of earthquake on eve of New Year, 1 January 2016 was recorded at magnitude of 4.2 on Richter scale. The Oklahoma Corporation Commission is implementing the action plan on five waste water injection wells located in 10 miles of the centre of earthquake activity. However, the earthquakes caused minor loss in the northern part of Oklahoma City and no injuries were reported, according to US News. 

Oklahoma is one of the major earthquake-prone areas in the world. Oklahoma witnessed about a dozen earthquakes of magnitude of 3.0 or above it in 2012. The number was staggering at over 800 in 2015. Baker further added that "responding to the swarm of earthquakes in the region was an ongoing process."

According to a report by News9.com, Oklahoma regulator is aiming at reduction in wastewater disposal volume by 50 percent and other waste by 25 percent. The regulator has also directed other wells within the 15 miles radius of activity to conduct reservoir pressure testing also. The regulator said there was no objection from operators.

The areas where injection wells are located are prone to earthquakes. The injection wells pump salty wastewater, which is a byproduct of oil and gas production process. The salty wastewater runs deep into the earth. 

The Huffington Post reports that a latest study by the US Geological Survey indicated that the rise in number of earthquakes was due to the increased industrial activity. The study traced back to 1920s analyzing wastewater injection methods in Oklahoma. It's estimated that about 1.5 billion barrels of wastewater was disposed underground in Oklahoma in 2015, as per the data by the Oklahoma state government.

The studies further indicate that wastewater disposal induce earthquakes in certain areas. It's estimated that about 200 million barrels were disposed in the Oklahoma state every month in 2015, according to George Choy, a U.S. Geological Survey seismologist in Denver.