By Anastasia Pantsios
A study by seven researchers from California, Colorado, Massachusetts, New Mexico, North Carolina, Ohio and the UK, The Environmental Costs and Benefits of Fracking, said “Unconventional oil and natural gas extraction enabled by horizontal drilling and hydraulic fracturing [fracking] is driving an economic boom with consequences described from ‘revolutionary’ to ‘disastrous.’ The reality lies somewhere in between.”
The studies findings were many, including that fracking “generates income and, done well, can reduce air pollution and even water use compared with other fossil fuels.” But it also found it can reduce investment in renewables and when done carelessly, can release toxic chemicals into the environment. It also agreed: fracking causes earthquakes.
In a section headed “Induced Seismicity,” the study said, “The reactivation of faults from hydraulic fracturing, wastewater disposal and other processes such as CO2 sequestration occurs by increasing the pore pressure and therefore reducing the effective stress within a fault zone. The increased pressure allows elastic energy stored in rock to be released more easily, much like removing weight from a box to make it easier to slide along the floor. Injecting fracturing fluids or wastewater underground can intersect a fault zone directly or transmit a pulse in fluid pressure that reduces the effective stress on a fault.”
Although it says there are only a ‘handful” of documented cases of earthquakes caused directly by fracking itself, none with a magnitude of more than 4.0, and that the number is small compared to those induced by mining and dams, many more earthquakes were caused by wastewater injection, an offshoot of fracking. Those earthquakes are not only more numerous but of greater magnitude.
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