CC: G Thomasen
Should you worry that fracking will cause earthquakes?
The short answer is: probably not.
But as more studies are conducted, researchers are
developing their understanding of how the fracking process
interacts with seismic activity.
Last year, a widely-cited study concluded that
compared to other kinds of mining, fracking usually only causes
minor tremors. But two papers in the past twelve months suggest the
processes associated with fracking could increase the likelihood of
We take a look at the evidence.
Fracking and earthquakes
Hydraulic fracturing - known as fracking - involves
pumping a fluid made of water mixed with chemicals at high pressure
into a drilled well. The fluid creates fractures in the rock,
making it possible to extract oil or gas trapped there. So fracking
essentially causes minor earthquakes by design, as cracking the
rock causes tremors.
But research shows fracking very rarely causes
earthquakes people can actually feel. The US Geological Survey
found the number of small earthquakes in the USA increased
significantly as the fracking industry was developed there. But the
vast majority of those earthquakes were "micro" earthquakes
registering less than 1 on the
moment magnitude scale - a modern version of the better
known Richter scale.
Shale gas exploration is simply not
in the "premier league" of serious earthquake causes, says
Professor Richard Davies, director of Durham University's Energy
Research Institute. Its study of
198 locations showed fracking caused much smaller tremors than
other mining processes. Davies has said most fracking induced
earthquakes release less energy than someone
jumping off a ladder onto the floor.
The Durham study caught the media's attention, with
swathe of headlines
declaring fracking was not a significant cause of
earthquakes. But it is worth pointing out that fracking has been
linked to some earthquakes that have been felt, if only in three
places: one each in Lancashire, the USA, and Canada.