A pair of moderate earthquakes shook northwest Oklahoma late Wednesday night, part of a swarm of Sooner State temblors that has produced more than two dozen quakes in less than 24 hours.
A 4.7-magnitude tremor was followed 30 seconds later by another 4.8-magnitude quake centered in a sparsely populated area about 20 miles northwest of Fairview, Oklahoma, about 97 miles northwest of Oklahoma City. The quakes struck at depths of 2.1 and 3.7 miles below the surface.
The 4.8-magnitude quake was the strongest in the Sooner State since the November 2011 swarm that included the state’s strongest on record, a 5.6-magnitude temblor in Prague on Nov. 6, 2011. It was the fourth strongest quake on record in Oklahoma, according to the Oklahoma Geological Survey (OGS).
This was one of 30 separate earthquakes of magnitude 2.5 or greater reported in Oklahoma within a 19-hour span from Wednesday evening through early Thursday afternoon. Twenty-seven of those, including the two strongest quakes mentioned above, were clustered in southern Woods County.
In 2015, 907 quakes of magnitude 3.0 or greater were reported in Oklahoma, up from 584 in 2014, according to KFOR-TV.
There were only 42 such earthquakes in the state in 2010 and 1 such tremor in 2005.
According to the USGS, there have been 30 such earthquakes already in 2016, the most recent being a preliminary magnitude-4.0 tremor near Fairview at 1:59 p.m. Thursday.
And its only the 8th January 2016.
And just if you think the onset of fracking and the increase in quakes was just a coincidence – here is a plot of the number of quakes over time.