Fracking Earthquake in Oklahoma?
by Buck Quigley - posted 11:40 am, November 7, 2011
Click here to read a widely-distributed Associated Press story about the 5.6 magnitude earthquake in Oklahoma over the weekend. The region has seen an increase in seismic activity in recent years.
From the article:
Scientists are puzzled by the recent seismic activity. It appeared the latest quake occurred on the Wilzetta fault, but researchers may never know for sure. Earthquakes that hit east of the Rocky Mountains are harder to pinpoint because the fault systems are not as well studied as major faults like the San Andreas in California.
Arkansas also has seen a big increase in earthquake activity, which residents have blamed on injection wells. Natural gas companies engaged in hydraulic fracturing, or fracking, use fluid to break apart shale and rock to release natural gas. Injection wells then dispose of the fluid by injecting it back into the ground.
There are 181 injection wells in the Oklahoma county where most of the weekend earthquakes happened (emphasis added) said Matt Skinner, spokesman for the Oklahoma Corporation Commission, which oversees oil and gas production in the state and intrastate transportation pipelines.
But natural gas companies claim there is no proof of a connection between injection wells and earthquakes, and a study released earlier this year by an Oklahoma Geological Survey seismologist seems to back that up. It found most of the state’s seismic activity didn’t appear to be tied to the wells, although more investigation was needed.
“It’s a real mystery,” seismologist Austin Holland of the Oklahoma Geological Survey said of the recent shaking.
“At this point, there’s no reason to think that the earthquakes would be caused by anything other than natural” shifts in the Earth’s crust, Holland said.
Earle said he couldn’t comment on the relationship between fracking, injection wells and earthquakes.
According to the USGS, earthquakes have been triggered by human activity in the past.