Mild earthquake linked to fracking oil extraction activities:
"Ohio Department of Natural Resources Director James Zehringer had announced on Friday that one such well -- which injects "fluid deep underground into porous rock formations, such as sandstone or limestone, or into or below the shallow soil layer," the U.S. Environmental Protection Agency explains -- was closed after a series of small earthquakes in and around Youngstown. Then on Saturday, a magnitude 4.0 earthquake struck that released at least 40 times more energy than any of the previous 10 or more tremors that had rattled the region in 2011. Andy Ware, deputy director of Ohio's natural resources department, told CNN on Sunday that Zehringer and Gov. John Kasich subsequently ordered that four nearby injection well projects will not open in the coming weeks, as had previously been planned. They 'll be inoperational until a determination is made in an investigation of a possible link between the earthquakes and the fluid-injection wells
, he added."
The media is usually confusing fracking with saltwater disposal wells. Fracking is a one time process for increasing porosity of a formation immediately around the well at the time of completion. A saltwater disposal well is normally a well (oil or gas) that has played out and is used to return unwanted saltwater back where it came from. Fracking only affects an area within a few hundred feet of the well.
If small earthquakes are triggered, it means that stresses in the fault lines were already present and are being gradually relieved. Having a number of small earthquakes seems preferable to letting the stress build up until it triggers a large earthquake.
"Researchers now say that they can calculate the highest magnitude earthquake that such an operation could induce — though it won't determine the likelihood of a quake occurring. The model is crude, but it should be “good enough” to use in the field
, says Arthur McGarr, a geologist at the US Geological Survey in Menlo Park, California, who presented the work yesterday at the annual meeting of the American Geophysical Union in San Francisco, California. “The method could help engineers trying to plan for future earthquakes know what to plan for,” he adds."
The people opposing the fracking technologies are the same people opposed to all uses of crude oil and natural gas as power sources.