“Oklahoma has had nearly double the number of earthquakes as California, local news reported after five earthquakes on Thursday morning rattled an area of the state where oil and gas drilling is prevalent.
While California recorded 88 earthquakes of a magnitude 3.0 or greater this year, 174 of the same intensity have shaken Oklahoma. On Thursday, the region was hit by five quakes with magnitudes higher than 3.0 — the magnitude at which tremors can easily be felt, Oklahoma City’s KOCO news reported.
Whereas California’s quakes are spread throughout the state, seismic activity in Oklahoma is concentrated in the central and northern part of the state — areas where oil and gas drilling, otherwise known as hydraulic fracturing or fracking, has increased in recent years. In Oklahoma as a whole, drilling doubled between 2009 and 2012.
The rise in oil and gas drilling in the state has paralleled increasing earthquake activity. Previously, the state averaged about one quake per year, but that has increased to at least one a day, KOCO reported.
Seismologists have concluded that fracking — a process where water, sand and chemicals are shot underground at high pressure to release trapped oil and gas deposits — can cause small earthquakes.
At the Seismological Society of America’s annual meeting in May, scientists said that underground disposal of vast amounts of wastewater generated by fracking likely induce earthquakes by changing the state of stress on existing faults.”
Read more: Aljazeera America