Hydraulic fracturing - commonly known as fracking - has been
responsible for just two earthquakes ever around the world,
according to the National Research Council.
Acting on a request from Congress and the Department of Energy, the
NRC released a special report titled, "
Induced Seismicity Potential in Energy
", which sought to uncover the connection between energy extraction
techniques (like fracking and
well drilling) and earthquakes.
While the report did reveal that fracking and other similar
activities can cause earthquakes, the number of such seismic events
was relatively small.
Over the past 90 years, human activity has been proven to be the
cause of only 154 earthquakes, which were all classified as either
small or moderate. Of those, 60 were in the United States and only
two were the result of fracking.
This is compared to the annual average of about 14,450 global
earthquakes registering a magnitude of 4.0 or higher each year.
One of the key findings of the report was that the injection or
extraction of fluid into or from the earth could affect subsurface
pore pressure and thus cause a seismic event. Operations that try
to maintain a balance between the amount of fluid
in and taken out of the earth might induce fewer seismic events,
according to the report.
This finding might help to explain why fracking has been behind the
two tiny earthquakes, which were in Oklahoma (2.8 magnitude) and
England (2.3). The
extraction process sees millions of gallons of chemical- and
sand-laced water injected into the ground to crack shale rock,
releasing the hydrocarbon. Once this water is removed from the
well, it needs to be disposed of and drilling wells for this
purpose is a common technique in the industry.
Thus, there are a number of opportunities for fracking operations
to potentially alter subsurface pore pressure and cause seismic
Despite these risks, the very low number of earthquakes connected
to fracking likely means that there isn't much seismic
posed by such activities.
"There's a whole bunch of wells that have been drilled, let's say
for wastewater and the number of events have been pretty small,"
professor of economic geology at the Colorado School of Mines and
report chairman Murray Hitzman said. "Is it a huge problem? The
report says basically no. Is it something we should look at and
think about? Yes."
Geological Survey seismologist William Ellsworth told
The Associated Press
that he agreed with the NRC's findings, stating, "hydraulic
fracturing does not seem to pose much risk for earthquake
While the report does show that humans are responsible for some
seismic activity, the amount is very, very small. Still, it is
unlikely that the findings of the report will quell some of the
protests that have been rising up around the country (and in other
parts of the world) over fracking.
Its opponents maintain that fracking can contaminate groundwater,
despite the findings of several major studies to the contrary.
These critics have helped to shape public opinion about the natural
gas extraction technique, putting operators behind the proverbial
eight-ball when it comes to convincing landowners and
municipalities to let them drill.
Fixing this public opinion issue will be essential for not only the
natural gas industry but the U.S. as a whole, as fracking has
allowed America to become the top producer of the hydrocarbon
worldwide. Further, it appears that natural gas will be a major
part of the solution to the world's energy needs over the coming
decades as many countries seek to move away from nuclear power.
to combat this, the International Energy Administration released a
special World Energy Outlook, titled Golden Rules for a Golden Age
, which sought to build a consensus between the industry and its