LiveScience: "Building owners and government officials should have a special concern for older, unreinforced brick structures, which are vulnerable to serious damage during sufficient shaking," Bill Leith, a USGS senior science adviser for earthquakes and geologic hazards, said in the joint statement.
While scientists haven't ruled out natural causes for the increase, many researchers suspect the deep injection wells used for the disposal of fracking wastewater could be causing the earthquake activity. Fracking, short for hydraulic fracturing, is a method of extracting oil and gas by cracking open underground rock.
Ongoing studies have found a link betweenOklahoma's high-volume wastewater injection wells and regions with an uptick in earthquakes.
According to the USGS, the number of quakes magnitude-3 and stronger jumped by 50 percent in the past eight months in Oklahoma. Some 183 earthquakes of magnitude 3 or greater struck between October 2013 and April 14, 2014. The state's long-term average from 1978 to 2008 was only two earthquakes of magnitude 3.0 or larger per year.
If the earthquakes are caused by wastewater injection, then the activity could continue or decrease with future changes in well usage in the state.
