Enlarge / The incredible flurry of (mostly small) earthquakes in Oklahoma has been clustered around areas of wastewater injection in deep disposal wells (shown in warm colors). (credit: Langenbruch and Zoback (2016), Science Advances)
The onset of Oklahoma’s earthquakes several years ago suddenly changed life in the north-central part of the state. But since they are self-inflicted, this seismic shift need not be a permanent one.
The earthquakes have been triggered by the injection of large volumes of wastewater in deep disposal wells, which is able to raise fluid pressure and loosen long-locked faults in the crystalline “basement” rock below. The wastewater comes from oil and gas wells in the area, which cough up a lot of dirty, salty water along with the hydrocarbons.
Just a few weeks ago, a magnitude 5.0 earthquake caused a fair amount of damage to buildings in Cushing—buildings that were never designed to withstand seismic activity. And in September, a magnitude 5.8 quake in Pawnee set a historical record for the state.
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Source: Ars Technica – Oklahoma earthquakes should be on the decline