Number Of 3.0 Or Stronger Earthquakes In Oklahoma Up 50% YOY In 2015
The number of earthquakes in Oklahoma rose 50 percent last year, easily surpassing the record number that hit the state in 2014. Oklahoma Geological Survey (OGS) data show that the state was shaken by 881 earthquakes of magnitude 3 or greater, or an average of 2.4 per day. That's up from 585 in 2014. U.S. Geological Survey data show that California had 128 such quakes in 2015.
Scientists and state officials say the increase in earthquakes in Oklahoma likely has been caused by wastewater disposal from oil and gas operations. Oil production methods that yield unusually large volumes of water have combined with favorably aligned faults under the state to cause the unprecedented shaking.
The data are subject to revision. USGS records appear to show at least one late-December quake not reflected in OGS records. The number of quakes per month hit a high of 105 in June. The lowest number occurred in September and December, which both saw 55 quakes magnitude 3 or greater.
Among the 29 quakes of magnitude 4 or higher was a magnitude-4.3 quake on Dec. 28. It made front-page news in Oklahoma City because it was centered just north of the city in Edmond. It was followed by a magnitude-4.2 quake on New Year's Day and numerous smaller shocks.
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