Scientist believes drilling injections set off Youngstown earthquakes
Injecting drilling wastewater and other brine deep underground probably caused several earthquakes near Youngstown in 2011, according to a scientist who is helping Ohio study the tremors.
Eastern Ohio had 11 earthquakes since March, and their pattern and power isn't normal for the region or natural quakes, said John Armbruster, a seismologist at Columbia University. Natural quakes usually have one main shock and several aftershocks. These have been getting larger, spread out over several months, in an area where that type of regular seismic activity isn't common, Armbruster said.
"Things look different than they did before," Armbruster said on Monday. "It's not absolute proof, but it seems the doubt in my mind is small based on my 40 years' experience studying earthquakes."
A 4.0 quake on Saturday was the latest to hit the region, centered five miles northwest of Youngstown, according to the U.S. Geological Survey. The day before, the Ohio Department of Natural Resources halted operations at a deep-injection disposal well fewer than three miles away.
After Saturday's quake, the department put a moratorium on four other disposal wells that were about to open nearby.
"The way we're looking at it, there's enough correlation," said Andy Ware, the department's deputy director, noting the depth of the weekend quake was closer to the well bottom than the previous quakes had been. "Putting all that together, we think it's reasonable to halt all future injections within a five-mile radius until we have a better understanding of what may be causing the seismic activity."
Officials at the site's owner, Northstar Disposal Services LLC, and the affiliated company, D&L Energy Inc., could not be reached for comment.
Armbruster, Ohio state scientists and a researcher at Youngstown State University set up four seismographs around the injection well in early December, Armbruster said. Their data led state officials to ask for the well shutdown on Friday, Ware said.
The quake on Saturday happened within 24 hours of the shutdown, possibly from pressure still built up, Ware said. Armbruster hoped to have data from that quake by last night, but collection may have been delayed by snow, he said by phone from New York.
Fluid disposal increased in Ohio in 2011 likely because Pennsylvania gas drillers were shipping more wastewater across the border, Ohio officials said last summer. Ohio has a growing number of injection wells, now at 177, compared with six in Pennsylvania, where there isn't as much cheap, permeable and available space underground.
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