More details on last Friday’s mini-quakes in Ohio.
Below is the latest report from the New York Times.
January 1, 2012, New York Times
Disposal Halted at Well After New Quake in Ohio
By HENRY FOUNTAIN
An official in Ohio said on Sunday that the underground disposal of wastewater from natural-gas drilling operations would remain halted in the Youngstown area until scientists could analyze data from the most recent of a string of earthquakes there.
The latest quake, the 11th since mid-March, occurred Saturday afternoon and with a magnitude of 4.0 was the strongest yet. Like the others, it was centered near a well that has been used for the disposal of millions of gallons of brine and other waste liquids produced at natural-gas wells, mostly in Pennsylvania.
The waste, from the process called hydraulic fracturing that is used to unlock the gas from shale rock, had been injected under pressure into the well, which is 9,200 feet deep. Scientists had suspected that some of the wastewater might have migrated into deeper rock formations, allowing an ancient fault to slip. Similar links between disposal wells and earthquakes have been suspected in Arkansas and Texas.
Andy Ware, deputy director of the Ohio Department of Natural Resources, which regulates gas drilling and disposal wells, said the state asked on Friday that injection at the well be halted after analysis of the 10th earthquake, a 2.7-magnitude temblor on Dec. 24, showed that it occurred less than 2,000 feet below the well. Because of a lack of data, depth estimates of earlier earthquakes had been far less precise.
The owner of the well, D&L Energy Group of Youngstown, stopped injection at 5 p.m. Friday, Mr. Ware said.
When the stronger quake occurred less than 24 hours later, Mr. Ware said, state officials decided to institute a moratorium on the injection of drilling waste within a five-mile radius of the well, “until we are able to take a closer look at the earthquake data that is available.” There are no other disposal wells in operation in the area, Mr. Ware said, but four are under development “and would not come online until we’re able to be sure.”
With the increased production of gas from shale in the United States, the process of hydraulic fracturing, or fracking, has come under fire for its potential to pollute the air and contaminate drinking water. But the events in Youngstown — and a string of mostly small tremors in Arkansas, Oklahoma, Texas, British Columbia and other shale-gas-producing areas — suggest that the technique may lead, directly or indirectly, to a dangerous earthquake.
There have been no reports of significant damage from any of the Youngstown earthquakes, which until Saturday were about 2.1 to 2.7 in magnitude.
According to the United States Geological Survey, the more powerful earthquake on Saturday was felt throughout northeastern Ohio and northwestern Pennsylvania, and as far as Morgantown, W.Va., and even Toronto. One resident in the Youngstown area said that from the way his house shook, he had thought a tree had fallen on it.
The more precise data from the Dec. 24 quake came from instruments installed by scientists from Lamont-Doherty Earth Observatory, a part of Columbia University. John Armbruster, a seismologist with Lamont, said that the data from the Saturday quake should be available within a few days, and that analysis should help pinpoint the location of the fault that slipped.
“In our minds, we were already pretty convinced that these events were connected to the well,” Mr. Armbruster said. “Having that many earthquakes fairly close to a well in Ohio, where there aren’t a lot of earthquakes, was suspicious.”