TOPEKA — The decision by state regulators to limit injection of saltwater deep underground after drawn to the surface by oil producers coincided with diminished intensity of earthquakes in south-central Kansas, a state geologist said Tuesday.

The Kansas Corporation Commission is poised to renew for another six months the injection restraints applicable in Harper and Sumner counties that were inspired by the proliferation of earthquakes rattling the region’s residents.

Rex Buchanan, interim director of the Kansas Geological Survey, said during a forum at the Kansas Energy Conference in Topeka the decline in magnitude of earthquakes mirrored adoption of the KCC’s rule in March.

“The consensus seems to be that we’ve seen a dropoff of larger events,” he said. “You could very well correlate a drop in activity with the KCC order. There are a lot of variables in play.”

Buchanan said more extensive analysis was necessary to wade through natural and man-made possibilities. A precipitous drop in drilling in face of falling oil prices and potential lack in tension along fault lines are probable factors, he said.

There seems to be little dispute, Buchanan said, that intensification of horizontal drilling for reclusive deposits coincided with dramatic expansion in the volume of waste brine held for injection far below ground. As companies forced saltwater beneath the surface, he said, earthquakes in the region became more frequent and climbed the Richter scale. Buchanan said the state recorded approximately 125 earthquakes in 2014, which is about five times the historical average.

“The same time we’re seeing these dramatic increases in earthquake activity, we also see dramatic increases in saltwater disposal,” he said.

Buchanan said influx of quakes can’t be directly linked to hydraulic fracturing, a process whereby water, chemicals and sand are pumped at high pressure to break rock and release oil or gas trapped in shale formations.

Gov. Sam Brownback, in opening remarks at the conference, lauded the KCC for doing a “nice job” stabilizing the earthquake situation.

Brownback, who has solar panels on his Topeka house, hailed demise of the state’s renewable energy portfolio standard compelling 20 percent of energy production to be from renewable sources — wind and solar, for example — by 2020.

The governor said repeal of the standard created a more stable business environment for wind investment that will result in construction of more turbines in Kansas.

The Missouri Public Service Commission’s rejection in July of a proposal by Clean Line Energy Partners to build a high-voltage transmission line through several Missouri counties will inhibit the ability of Kansas wind farms to export power to Illinois, the governor said. Kansas already had granted permission for the new line.

“That’s one that really opens up wind production in the region,” Brownback said. “For us, transmission lines are critical. A lot of wind is going to be exported.”

Todd Foley, a senior vice president with the American Council on Renewable Energy, said at the conference he was bullish on potential of solar and wind to serve a greater portion of domestic consumer demand.

“Of course, Kansas is a good case in point,” Foley said. “Kansas is very much of a leader on renewable energy development, especially on the wind side. Wind has really scaled up.

“The key thing is this growth is driving down costs. Wind costs have come down by 58 percent since 2009. That’s going to continue on down. There is dramatic growth in the market,” he said.

Foley said the U.S. Department of Defense was among leading investors in solar technology, both in terms of backpack units for individual soldiers on patrol and for large arrays serving entire military installations. Dozens of large corporations — Walmart is No. 1 — are turning to sun-driven power to reduce electric bills, he said.

“They’re all about cost,” Foley said. “They have nothing but bottom-line pressures.”

Ed Cross, president of the Kansas Independent Oil and Gas Association, said low crude oil prices had damaged the state’s oil and gas interests. He said approximately 115 drilling rigs were operating in Kansas at this time in 2014. At the moment, he said, about 40 are drilling for deposits.

“It’s a tough time in the industry,” Cross said. “They cut everything they can to try to keep the people. They feel terrible when they have to lay off people.”

He said the often-cited world price for a barrel of crude stood at about $47, but producers of Kansas common crude received $34 per barrel.

Maneuvering by OPEC to hold market share by squeezing out marginal producers, growth in the state’s severance tax on oil and gas, and an onslaught of federal regulation with an ideological taint challenge Kansas’ energy sector, Cross said.