By Ed Runyan
A soon-to-be published study of earthquakes near two brine-injection wells on state Route 169 just north of Niles indicates that the deeper of the two wells apparently caused the quakes.
Seismologists at Miami University in Oxford, Ohio, used data they collected just after a 2.1-magnitude Aug. 30, 2014, earthquake to report to the Ohio Department of Natural Resources that the quake’s epicenter was “almost directly beneath” the injection well, said Mike Brudzinski, one of the paper’s authors.
Furthermore, the quake was part of a small sequence of earthquakes, the seismologists told ODNR.
ODNR ordered the owner of the wells — American Water Management Services, a subsidiary of Avalon Holdings of Howland — to shut down both wells soon afterward while the state further investigated.
ODNR later allowed operation at the shallower well — which pumps brine about 4,700 feet down — to resume. The deeper one — which injected brine 9,100 feet deep — remains closed.
The study Brudzinski and two others wrote says the Aug. 30 event did not have the characteristics of a naturally occurring quake — a primary quake followed by aftershocks of smaller magnitude.
Instead, the 2.1 quake was part of a “swarm” of quakes — multiple recorded quakes over time with the largest one occurring at the end of the sequence.
The seismic events associated with the deeper well were recorded starting in early July and continuing through September, Brudzinski said by telephone.
“After the injection wells were stopped, we saw the number of earthquakes kept dwindling down to a very small level,” Brudzinski said.
The study has not yet been peer-reviewed, but its findings preliminarily suggest there is a “direct relationship” between the injection at the Weathersfield well and the earthquakes.
This is not the first time for induced earthquakes in the Mahoning Valley. Other examples noted in the study include the New Year’s Eve 2011 earthquake in Youngstown that was later tied to brine injection at the D&L Energy well on Ohio Works Drive, and the April 2014 quakes at the Carbon Limestone Landfill in Poland Township associated with Hillcorp Energy Co. fracking wells.
All of those examples and one in Harrison County, 60 miles south of Youngstown, produced seismic “swarms,” Brudzinksi said.
The good news is that the review of seismic data Brudzinski and his colleagues conducted found no indication of induced earthquakes elsewhere in Trumbull County, despite the large amount of brine injection taking place in Vienna and Newton townships, Brudzinski said.
The bigger picture for scientists is to determine whether there are geological faults in the basement rock under this part of Ohio that makes it more prone to induced seismic activity, Brudzinski said.
None of the induced seismic activity in Trumbull and Mahoning counties was large enough to cause much damage, but the issue needs to be studied to determine whether the earlier seismic events are “harbingers of larger events,” he said.
Ohio does have naturally occurring earthquakes, including a 3.5-magnitude event that hit Athens in November 2013, he noted.
Weathersfield Township trustees, who became aware of the Miami University study in early February, responded to the study by writing to Stephen Kilper, vice president of AWMS, asking him to meet to develop an emergency plan to address the potential for damage from future seismic events.
“Our township is home to a dam that retains the water supply for approximately 300,000 households,” the letter says of the Mahoning Valley Sanitary District dam at Meander Reservoir.
“The three-mile radius that surrounds your facility contains residential areas, several large office buildings, schools, hospitals, apartment complexes and a senior center and housing complex,” the letter says.
Kilper on Monday said AWMS agrees with the Miami University findings but said the 2.1-magnitude event from Aug. 30 would have to increase 125 times to be large enough to be felt. Seismic activity can be felt at 3.0, and damage begins at 4.0, he said.
He said data from the four seismometers the company installed near the Weathersfield injection wells are automatically reported to ODNR. That same information will be provided to Weathersfield Township when the deeper well reopens. Any alerts that the company operating the seismometers sends out also will go to the Weathersfield Township police and fire departments, Kilper said.
ODNR issued a statement saying the agency has a copy of the Miami University report, “and our experts are in the process of reading it over.”
Eric Heis, public information officer, said there is a hearing date scheduled for March 11 in Columbus for AWMS to appeal the closing of its deeper well.