A newspaper analysis finds that the average number of 2.0 magnitude and higher earthquakes occurring in Ohio each year has risen.
The rise reported by The Columbus Dispatch coincides with an average increase in tremors nationally and to an increase in oil-and-gas drilling and deep injection activity in eastern Ohio.
Ohio Department of Natural Resources data reviewed by the newspaper showed Ohio averaged two earthquakes annually of 2.0 magnitude or greater between 1950 and 2009. Between 2010 and 2014, that average rose to nine.
Five minor earthquakes recorded southeast of Youngstown last Monday and Tuesday are being investigated.