April 20, 2015
Hutchinson Earthquakes appear to be striking Kansas less frequently but officials say it's too early to say whether new rules are the reason.
The Hutchinson News reports the Kansas Corporation Commission issued an order on March 20 that set a new maximum daily amount of waste saltwater injection amounts in Harper and Sumner counties. The order also further limited disposal levels in five specific areas of "seismic concern."
The Kansas Geological Survey has recorded more than 200 earthquakes since Jan. 1, 2013, after detecting just five over the previous 10 years, according to its website. Since September, the region has had an average on 17 earthquakes of magnitude 2.0 or higher each month. A 4.9-magnitude quake near Milan in Sumner County, struck in November.
A vast majority of those earthquakes have been recorded in south-central Kansas, where much of the recent hydraulic fracturing activity has occurred.
State scientists and regulators have suggested the injections, which dispose of the saltwater byproduct of oil and gas production from hydraulic fracturing, are likely triggering the tremors along existing but previously unknown fault lines in the region.
The order, which went into effect March 30, will cut injection in some wells by up to 60 percent when fully implemented by late June. The order only affects 20 wells.
The Kansas Corporation Commission decided to reduce injection amounts instead of stopping them altogether because there was concern that a large change in disposal volumes would actually trigger bigger earthquakes.
According to the commission's documents, more than 110 million gallons of wastewater were injected beneath Harper and Sumner counties in 2014. Only 51.8 million gallons were injected under Harper County in 2013, according to the commission's order.
The commission, along with the Kansas Geological Survey, identified elongated areas of seismic concern based on clusters of earthquakes.
"We did not look at specific wells, but looked at how earthquakes were clustered and at subsurface linear features that might indicate where faults might be," said KGS Director Rex Buchanan.
Originally published at: http://www.tonganoxiemirror.com/news/2015/apr/20/officials-early-say-fewer-quakes-due-fracking-limi/