North Huntingdon approves additional seismic testing
North Huntingdon commissioners last week approved a second application to allow seismic testing in the township to determine areas that might contain natural gas in Marcellus shale.
Cougar Land Services plans to conduct three-dimensional underground seismic testing on 322 acres near the soccer field complex off of Turner Valley Road, according Michael Turley, the township's assistant manager.
“The area where they want to do the testing is at the fringe of a many-square-mile area to the south and west of the township,” Turley said.
Seismic testing typically involves drilling a series of several-inch-wide “shot holes” about 20 to 30 feet into the ground in which small, explosive charges are lowered and ignited. The vibrations from the charges travels through the earth and “echoes back” when they encounter rock formations that could contain deposits of natural gas, Turley said. Engineers use the sound waves to make a geological map.
Representatives of Cougar, which is based in Sugar Land, Texas, also informed the township that they might use trucks with Vibroseis equipment, Turley said.
“The charges need to be placed a certain distance apart for accurate testing,” Turley said. “But they are not permitted within 75 feet of a home, so that's where they would use the Vibroseis trucks.”
The “thumper” trucks are equipped with a plate that is lowered to the ground to emit vibrations that mimic the vibrations emitted by an explosive, said Turley, adding that Vibroseis equipment also can be used to test the area below a paved road without damaging the surface.
Turley, who has attended seminars at which the device was demonstrated, said the trucks will have minimal impact on the area.
“The vibration is fairly minor and dissipates within about 75 feet. It's about the same as a garbage truck driving by,” he said.
In February, commissioners approved the first round of seismic testing in the township, which was performed by McDonald Land Services of Washington, Okla.
Testing, which was completed in May, was conducted in Braddock's Trail and Turner Valley parks using the explosive charges.
Tony LaRussa is a Trib Total Media staff writer. Reach him at 412-871-2360, or at firstname.lastname@example.org.