Does Fracking Cause Earthquakes?

Fracking, or hydraulic fracturing, to give it its full name, is the process of extracting natural gas from shale deposits through the injection of hydraulic liquid into the rock. This fractures the rock and releases the gas, and it has been hailed by its champions as a much cleaner and safer alternative to coal mining. It is believed by many that the employment of fracking can buy us valuable time, limiting the effects of climate change, while we endeavour to put more sustainable systems in place.

However, opponents of the process claim that – among other concerns – fracking causes earthquakes. Induced seismicity – or increased earthquake activity brought about by human activities – has been linked to fracking in several sites around the world, most noticeably in the UK, the USA and Canada. How serious a problem is this?

How is Fracking Responsible for Induced Seismicity?

Induced seismicity is linked to two possibilities: the removal of material from the earth, as occurs in mining and other activities, and the injection of liquid into the earth, effectively acting as a lubricant for the fault zone, which is the concern linked to fracking. It is thought that perhaps the fluids may leak into a fault zone, thus increasing the likelihood of earthquake activity.

How many Instances of Earthquakes have been linked to Fracking?

A recent study by Durham University into the causes of earthquakes over the last 85 years unearthed revealing results about induced seismicity. The study uncovered 79 incidents of induced seismicity linked to fracking which were confined to just three shale gas fields. One of these was in the UK, and the largest earthquake it produced was a mere 2.3 on the Richter scale – barely noticeable.

The largest earthquake worldwide linked to fracking was in Canada and reached 3.8. Although higher, the effects felt by such an earthquake would be akin to a large vehicle driving past your home – enough to shake the windows, but not enough to do any structural damage. Indeed, only four examples of a fracking-induced earthquake have been felt and recorded across the globe: the two listed above, as well as another in the UK and one in the USA.

How do Fracking-Induced Earthquakes Compare to other Induced Seismicity?

The number of examples of induced seismicity linked to mining is far greater than those associated with fracking. Moreover, mining has also produced far larger quakes than fracking. The same study shows that the largest earthquake on record in the last 85 years linked to mining was 5.6 on the Richter Scale, considerably more than those linked to fracking. Even more alarmingly, a 7.3 earthquake was linked to fossil fuel depletion in Azerbaijan and a whopping 7.9 earthquake in China was linked to reservoir creation.

Viewed in this light, the seismic activity brought about by fracking seems a great deal less frequent and less troubling than that incurred through mining, fossil fuel collection and other energy harvesting processes.

The Bottom Line

Though it appears that fracking most certainly does cause earthquakes, the vast majority of these will go unfelt by humans, and those that are felt are incredibly unlikely to cause any damage. If there are criticisms to be levelled at fracking, earthquake inducement is probably not one of the more serious. More pressing concerns, like methane leaks and groundwater contamination, are more deserving of debate, and have been dealt with by many fracking propagators, including Chris Faulkner of the Breitling Energy Corporation.