The Oxford Dictionary defines it as: the process of injecting liquid at high pressure into subterranean rocks, boreholes, etc. so as to force open existing fissures and extract oil or gas.
In order to liberate gases trapped in rock, oil and gas companies inject water, sand and some chemicals into the ground through high pressure. The pressure increases fractures in the rock, and the gas emerges and is piped out.
The process has been blamed for contaminating drinking water and in some cases causing earthquakes.
Experts believe the tremors are caused by hydraulic fracturing, or fracking.
Since the 1950s, there have been 120,000 wells that have been hydraulically fractured in Alberta. Four-thousand of them are around Fox Creek. There have been about 200 quakes in the Fox Creek area since December 2013. Each year, Alberta averages 30 earthquakes.
The Alberta Energy Regulator announced new requirements in February 2015, after several seismic events in the Fox Creek area. If a seismic event measuring 4.0 in magnitude or greater occurs within five kilometres of an operator, it must cease operations and inform the AER. If a seismic event between 2.0 and 4.0 occurs, operators must inform AER and invoke their response plan.
WATCH: The link between fracking and Fox Creek
Other provinces have looked at banning fracking. In 2014, Nova Scotia decided to ban fracking for onshore shale gas.
New Brunswick put a moratorium on fracking.
READ MORE: Commission on fracking seeking public input
There have also been protests across the country against the industry practice.
Opponents say fracking can cause other environmental problems, including increased greenhouse gas emissions.
Here’s an easy-to-understand explanation posted by SciShow on YouTube:
“It’s a myth to consider that hydraulic fracturing is responsible for all induced earthquakes, or even all injection-induced earthquakes,” said David Eaton, professor of Geophysics at the University of Calgary.
However, disposal of wastewater — be it left over from the fracking process or as a result of oil extraction — can also cause induced earthquakes.
“In either case, withdrawing or injecting fluids into the subsurface, there’s a known linkage for the potential of induced seismicity,” Eaton explained.
With files from