Furthermore, the study found the size and number of felt earthquakes caused by fraccing was low compared to other manmade triggers such as mining, geothermal activity or reservoir water storage.
However, the study also established beyond doubt that fraccing had the potential to reactivate dormant faults and described the ways the pumping of fraccing fluids underground could do this.
Durham Energy Institute Professor Richard Davies led the study that resulted in the report Induced Seismicity and the Hydraulic Fracturing of Low Permeability Sedimentary Rocks.
“We have examined not just fraccing-related occurrences but all induced earthquakes – that is those caused by human activity – since 1929,” Davies said.
“It is worth noting that other industrial-scale processes can trigger earthquakes including mining, filling reservoirs with water and the production of oil and gas.
“Even one of our cleanest forms of energy, geothermal, has some form in this respect.”
Davies said the seismic events caused by fraccing were low, even compared to other manmade triggers.
“Earthquakes caused by mining can range from a [Richter scale] magnitude of 1.6 to 5.6, reservoir filling from 2 to 7.9 and waste disposal from 2 to 5.7,” he said.
“By comparison, most fraccing-related events release a negligible amount of energy roughly equivalent to, or even less than, someone jumping off a ladder onto the floor.
“Of the three fraccing-related quakes that could be felt, even the largest ever in the Horn River Basin in Canada in 2011 had a magnitude of only 3.8. That is at the lower end of the range that could be felt by people.
“The widely reported quake at Preese Hall near Blackpool in 2011 had a magnitude of 2.3.
“So we concluded hydraulic fracturing is not a significant mechanism for inducing felt earthquakes.”
Not to say that it cannot happen though – it is just very unlikely.
“But there are ways to further mitigate against the possibility,” Davies said.
“The oil and gas industry can avoid faults that are critically stressed and already near breaking point.”
