A team of researchers from the US Geologic Survey is publishing this month a paper that shows a sharp increase since 2001 in the number of 3.0 and higher earthquakes in a region that runs from the west of Ohio to East of Utah. The paper finds that from 1970 to 2000 the average annual number of earthquakes greater than 3.0 in the area studied were 21, with the rate increasing to an average of 29 from 2001 to 2008, and to 50 in 2009, 87 in 2010, and 134 in 2011. See the abstract of the paper at: http://www2.seismosoc.org/FMPro?-db=Abstract_Submission_12&-sortfield=PresDay&-sortorder=ascending&-sortfield=Special+Session+Name+Calc&-sortorder=ascending&-sortfield=PresTimeSort&-sortorder=ascending&-op=gt&PresStatus=0&-lop=and&-token.1=ShowSession&-token.2=ShowHeading&-recid=224&-format=%2Fmeetings%2F2012%2Fabstracts%2Fsessionabstractdetail.html&-lay=MtgList&-find
The lead researcher in the paper, Mr. Ellsworth, told MSNBC that he believes the increased number of earthquakes is not associated with hydraulic fracturing, but instead with the disposal of drilling waste fluids in deep well injection sites, of which there are 144,000 in the USA.
www.msnbc.msn.com/id/46980665#.T4IkGpmZ3To. Going back 50 years, the scientific record includes a number of small earthquakes that have been linked to the disposal of liquids from various sources, including the Defense Department, under pressure in deep underground caverns.
No matter the source of the fluids, this issue requires responsible discussion and action to minimize the occurrence. Regulators in Ohio strengthened siting and operational rules for injecting underground drilling wastewater, for example, following the Youngstown earthquake.
Additionally, with an operating plant in Williamsport, Pennsylvania, Eureka can fully treat drilling wastewater so that it becomes fresh water and does not need to be injected deep underground. Eureka is seeking to expand its operations in Pennsylvania and Ohio.
The combination of treatment alternatives that reduces the volume of liquids that are injected and the stronger siting and operational rules adopted by Ohio are approaches that will likely spread to limit risks associated with injecting liquids underground.