A 5.1 magnitude earthquake shook northwestern Oklahoma Saturday afternoon, an event the U.S. Geological Survey said could relate to wastewater injection in the area.
The U.S. Geological Survey said the earthquake could have been caused by wastewater injection, which can involve taking the water used in fracking and injecting it into underground wells to not contaminate drinking water. If the quake is confirmed to be related to fracking, it would be one of the largest earthquakes caused by hydraulic fracturing.
The earthquake started at 12:07 p.m. EST Saturday with the epicenter about 20 miles northwest of Fairview, Okla. The epicenter was relatively shallow, just 4 1/2 miles below the surface.
Earthquakes typically take place between the surface and about 500 miles beneath the surface. There is a small fault line that runs through Oklahoma.
On Twitter, the USGS said the specific cause of the earthquake was unknown. “But, many quakes in area have been triggered by wastewater fluid injection,” the agency noted.
Hydraulic fracking involves shooting water or other chemicals into the Earth’s crust to release oil or natural gas trapped between layers of rock.
The earthquake is the largest in Oklahoma in five years. A 5.6 magnitude quake shook the state in 2011. Scientists determined that quake may have resulted from a human-caused 5.0 magnitude earthquake days before.
Seismic activity in Oklahoma has increased in recent years. While many speculate that increase in activity is due to fracking, it has yet to be confirmed by scientists.
