Oklahoma’s Geology Survey recorded an unprecedented 20 small earthquakes across the state on Tuesday, highlighting the dramatic increase of seismic activity that has occurred there as the controversial process of hydraulic fracturing — otherwise known as fracking — has spread across the state.
Though 18 out of the 20 earthquakes that occurred Tuesday were below Magnitude 3, rendering them mostly imperceptible, the largest one registered as a 4.3 near Guthrie, a city of more than 10,000 residents. And while U.S. Geological Survey scientists have said that Oklahoma is historically known as “earthquake country,” they also warn that quakes have been steadily on the rise; from 1978 until 2008, the average rate of earthquakes registering a magnitude of 3.0 or more was only two per year.
“No documented cases of induced seismicity
have ever come close to the current earthquake rates or the area over
which the earthquakes are occurring,” the Oklahoma Geology Survey said
in a recent presentation addressing
the alarming increase in quakes. By “induced seismicity,” the OGS is
referring to minor earthquakes that are caused by human activity,
whether that be fracking, mass removal mining, reservoir impoundment, or
geothermal production — anything that could disrupt existing fault
lines.
One of the most researched human activities that could be causing the dramatic increase in earthquakes is fracking. The process that could be causing the quakes is not the fuel extraction itself, but a process called “wastewater injection,” in which companies take the leftover water used to frack natural gas wells and inject it deep into the ground. Scientists increasingly believe that the large amount of water that is injected into the ground after a well is fracked can change the state of stress on existing fault lines to the point of failure, causing earthquakes.
