In less than a decade, one of the oil and gas industry’s most controversial drilling methods – wastewater injection deep into the underground – has created so many man-made earthquakes that it turned Oklahoma into a seismic hot spot.
In 2008, the Sooner State had just one earthquake severe enough to be felt by local residents. Seven years later, the number of quakes of this magnitude skyrocketed to more than 900.
Researchers believe that the staggering increase in earthquake frequency is caused by the oil industry’s activity in the area. Big oil started to inject wastewater or “saltwater” in the ground at great depths in its drilling operations.
According to a recently published study, the magnitude of the earthquakes produced by the oil industry is directly linked to the depth at which saltwater is injected. Researchers recommend lowering the depth of injections to keep seismic activity in check.
Oklahoma Sees Spike in Number of Man-Made Earthquakes
Oklahoma has over 10,000 injection sites statewide. These sites include wells that are used to get rid of wastewater and those for oil recovery purposes. Saltwater injections reach a depth of up to 1.2 miles (2 km) in an attempt to avoid the supply of fresh ground water.
From 2011 to 2017, the oil industry injected 2.3 billion barrels of wastewater every year deep into the ground. In 2013, a study revealed a link between oil wells and a spike in earthquake occurrence in those areas. The method even led to an earthquake of 5.8 magnitude.
In 2015, thanks to a series of new laws, the frequency of man-made earthquakes slipped, but the overall seismic energy is still considered above the safe level. In 2016, the largest earthquake in Oklahoma’s history hit at a 5.8 magnitude despite the new regulations.
Experts are concerned that the lower seismicity is linked to a dip in oil prices which halted the production rather than regulation.
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